This article is jointly authored by Raymond McDougall, David K. Joyce and Ian Nicklin. Except as otherwise credited, all photographs are R. McDougall photos.
Just north of Lake Superior, the Thunder Bay District of Ontario is world famous for its distinctive, ancient amethyst crystals. Thunder Bay amethyst has been known since the 19th century, and is remarkable for its variety – it occurs in all shades of purple from pale to deep, from warm to cool hues, it is often further coloured by inclusions (most often red, due to included hematite) and once in a while phantoms are also found. It is a long journey to the amethyst mines of the Thunder Bay District, and hopefully this article will bring this beautiful region, its history, geology, mines and collecting experience a bit closer!
Location
The Thunder Bay District is located along the northern shore of Lake Superior. The Thunder Bay District is a formal subdivision of the Province of Ontario comprising over 103,000 square km. The amethyst-producing region, within the Thunder Bay District, is located in an area approximately 60 km northeast of the city of Thunder Bay. Just to give you a sense of how long a drive it is to reach the amethyst area from major international centres, it is over 1200 km from Toronto and over 1000 km from Chicago. (Closer large cities are still a surprisingly long way from Thunder Bay: Milwaukee over 900 km, Winnipeg over 700 km and Minneapolis-St.Paul approx. 550 km). Flights from Toronto are frequent, but commercial air travel is not the most convenient when transporting major collecting gear or any decent amount of specimen material.
North of Superior
The land north of Lake Superior is rugged – it is stunning, wild country. It is one of the most beautiful regions in Canada, but because it is relatively remote from major population centres, it is not as well-known or as frequented as some of our more famous scenic locations. It is a land of the Canadian Shield, with exposed Precambrian rock, lakes and evergreen forests.
The distant hills are often quite rounded thanks to the glaciers, and in many places, the shoreline rock has been shaped into smooth forms, first by the glaciers, and since the end of the last Ice Age, by the unrelenting waves, ice rafts and deep frost
Inland from the shoreline, signs of the last glaciation are still readily apparent, with rock faces worn smooth, and interesting features like the deep, dark, round pools known as kettles, created by powerful glacial runoff, carrying rocks as abrasive agents. The most recent glaciers receded from the area approximately 10,000 years ago.
Even beyond the glaciers and away from the shoreline of Lake Superior, this region is constantly being visibly reshaped – by heavy storms, and often just by water as it makes its way from higher land down to Lake Superior.
Speaking of storms, Thunder Bay is named for the sound of the thunderstorms as they roll through. Severe thunderstorms are common throughout Ontario in the summer months, but they are just awesome in Thunder Bay, where the thunder booms around the bay and echoes off the surrounding landforms. (It is an amazing experience. Ideally not experienced in a tent.)
The Thunder Bay District is home to lots of wildlife, including large mammals such as moose, timberwolves and black bears.
From Early People to Modern Times
After the glaciers retreated, the first people moved in to inhabit the lands along the north shore of Lake Superior, approximately 10,000 years ago. Several peoples have lived in this region since that time, the Plano, the Shield Archaic, the Laurel and the Terminal Woodland peoples, and the Anishinaabe (including the Ojibwe, or Chippewa). They have hunted, fished, gathered berries and even mined native copper – and they have been active traders. Early inhabitants used canoes for water transportation – first, canoes were carved out of large tree trunks, and later canoes were made using lighter wooden frames covered by birch bark and assembled using a glue made largely from tree resins (combined with animal fat and soot).
Today, there are few tangible signs of most of these early peoples. In some places, small stone pits and piles of stone are evident, and artifacts have assisted researchers to better understand the past of the area. Painted red ochre pictographs are seen on the Lake Superior shoreline cliffs – these are comparatively recent, estimated to be 200-400 years old.
With the arrival of the first French explorers in the mid-17th century and the opening up of trade by the British and the Hudson’s Bay Company, life around Lake Superior began to change. Through trade, the French and the British engaged with the Ojibwe people. As the British continued to explore and develop these interior regions during the nineteenth century, prospecting and mining followed.
In the beginning, what is now the city of Thunder Bay was comprised of two separate settlements/towns (it was not until 1970 that they amalgamated as Thunder Bay). The first was Fort William, which was established in 1803 by the North West Company as a trading post for furs and other goods. After the merger of North West Company and the Hudson’s Bay Company in 1821, the importance of Fort William as a trading post diminished, although the settlement continued on and became a town.
In the latter half of the 19th-century, a second settlement, initially named Prince Arthur’s Landing, was founded nearby in connection with the Government of Canada’s post-confederation efforts to extend the railway from the Atlantic Ocean to the Pacific. Soon renamed Port Arthur, it was was initially supported by local silver mining. As the silver mining declined, the era of railway development was on the rise, and both Port Arthur and Fort William were to become important Canadian railway towns. Port Arthur was the key rail terminal for Western Canadian wheat, which was then loaded onto ships and transported through the Great Lakes.
Once the first railway across the north of Lake Superior was completed in 1885, trains were the major means of land transportation across the region for the next 75 years.
These same Northern Ontario railways are still fundamental Canadian transportation corridors today, linking Central and Western Canada. The echo of trains in the distance day and night is an evocative sound of this part of the country.
Because the land is so rugged, with steep hills and river gorges, the last section of the Trans-Canada Highway linking Thunder Bay with Sault Ste. Marie (at the eastern end of Lake Superior) took decades to complete and was only finally opened in 1960. Today the Trans-Canada Highway in this region runs like a ribbon through hundreds of kilometers of rocky forest, sometimes relatively close to the lakeshore, and sometimes much further north, where construction was more feasible.
Ancient Geology
The land north of Lake Superior is part of the Canadian Shield, and includes ancient rock types dating back to 2.7 billion years old. The landforms and rocks evidence mountains and volcanoes that have come and gone, and massive geological events including regional structural metamorphism, folding and major faulting.
The amethyst deposits of the Thunder Bay District are associated with the rocks of the Osler Group, formed during a late Precambrian stage of volcanism and faulting, from 1.2 to 0.9 billion years ago. In general, the amethyst deposits are in or near the granitic rocks, in proximity to the contacts between the rocks of the Osler and Sibley Groups. The faulting and related fracturing of these rocks during the late precambrian allowed for the intrusion of the fluids which ultimately led to the deposition of the amethyst crystals. These fluids precipitated the amethyst (and also silver, lead and zinc-bearing minerals at the localities where they occur) onto the walls of the fractures, creating crystal-lined veins and cavities. The faulting and fracturing – and therefore the nature and occurrence of ameythst-bearing veins – differs somewhat from locality to locality within the Thunder Bay District. Some brecciated zones are characterized by large numbers of relatively parallel small veinlets, while in other places much larger fractures are hosted by much more competent rock. The size of individual amethyst crystal-bearing vugs and cavities can vary significantly – they can be as small as 2 cm and a cavity 15 x 3 x 2.4 metres has been excavated. The vugs and cavities within a vein or berated zone are often interconnected with one another.
History of Thunder Bay District Amethyst Discoveries
Silver was discovered in the Thunder Bay District in the mid-19th century and soon silver mines were operating. Amethyst was found in these mines, and was described by W.E. Logan (founder of the Geological Survey of Canada, and namesake of weloganite) in a report in 1846. By 1887, G.F. Kunz was reporting a thriving trade and exports of amethyst from the Thunder Bay District for tourists and for building materials. However, by the early 20th century, two factors led to the decline of the Thunder Bay District amethyst trade: the silver mines began to close and large amounts of high-grade Brazilian amethyst began to appear on the market.
For mineral collectors, the most important amethyst discoveries were yet to come. In 1955, amethyst crystals were discovered northeast of Port Arthur in McTavish Township, but it was the discovery by Rudy Hartviksen in 1967 at Loon Lake (also in McTavish Twp.) that began the modern era of fine amethyst production from the Thunder Bay District. The deposit found in 1967 was to become the Thunder Bay Amethyst Mine, the largest commercial amethyst mine in the region. It has operated continuously since that time and is now named the Amethyst Mine Panorama. Many other localities in the Thunder Bay District have been operated since 1967, and perhaps the most prolific for producing fine, top-quality collector specimens has been the Diamond Willow Mine.
The Diamond Willow Mine
The Diamond Willow Mine works a vein in McTavish Township, in the Thunder Bay District, located on a claim block at the northern end of Pearl Lake. It was named by its owner, Gunnard Noyes, after the type of willow tree that grows at the site of the mine and is highly prized by wood carvers. From the late 1970s and for over 30 years, a section of the vein was leased and worked in the summers by the father-son team of David and Ian Nicklin. They collected with great care and produced some of the finest quality amethyst to have ever come from the Thunder Bay District. The Diamond Willow vein was also regularly worked by Gunnard Noyes, his sons Doug and Clark, and later his daughter Francis.
To give a small insight into what really lies behind the excellent amethysts mined during that time at the Diamond Willow Mine, the following account is written by Ian, together with a few photographs from mining in those days.
Amethyst Mining at the Diamond Willow Mine
My father, Dave Nicklin, and I first met Gunnar on the suggestion of the Ontario Geological Survey regional geologist in Thunder Bay 42 years ago, while on a summer rock collecting trip. Gunnar had worked in the mines at Sudbury for many years and had retired to the small railway stop town of Pearl, approximately 60 km northeast of Thunder Bay. He was a great source of stories and a remarkably generous man. Knowing of the amethyst riches in the region, he staked his several claims just north of the hamlet of Pearl but when we first met him they were not developed to any extent. The claims were only accessible by a narrow twisting trail or by canoe, up Pearl Lake.
On our first visit, my father and I canoed Gunnar’s ancient but still functional Atlas Copco Cobra plugger drill up the length of the lake and met him at the trailhead. I was 16 at the time. Although I was quite strong for my age, I clearly recall complaining about the weight of the drill as I struggled through the bush with it. Gunnar, a man well into 60s at this point, laughed at my complaints, grabbed the drill from me and hoisted it onto his shoulder with no fuss. (Anyone with any familiarity with Cobras knows what that takes and just how uncomfortable it is.) I think he was enjoying showing up the young pup.
We eventually reached a small clearing on an outcrop where there was evident signs of blasting and some amethystine rubble. This was the beginning of the Diamond Willow Mine. Gunnar drilled some holes with the plugger and prepared to put off some shots. He had stuffed some sticks of Forcite 40 into his pockets before heading up the trail. This was the first time we had seen blasting up close and as with most things associated with Gunnar it was memorable. He had some pre-cut fuse and a few blasting caps which had to be crimped onto the fuse with special plyers. In later years, we would use electric caps but these were still early days. He set the charges, lit the fuse (it would burn for about 30 seconds) and told us to find cover … which we did.
As we walked away – never run from an impending blast – to find shelter (with Gunnar yelling “Fire!”, the signal for anyone who might be nearby that an explosion was imminent) I became aware just how long 30 seconds can be. The anticipation of the bang made the seconds interminable. But off they went and I can still see the smoke slowly wafting through the trees and the smell of cordite in the air as we made our way back. And there lay our first amethyst specimens, which I still have to this day. We collected about 100 pounds or so of specimens and packed them into the canoe for the trip back. This was the beginning of a 42-year-long relationship, first with Gunnar and later with his sons.
My father was a teacher and so he had the summers off. While I was in school, we would return to the Diamond Willow every year, collecting for several weeks. Later my father and mother bought a trailer in a nearby camp and spent the summers there – I would join them as time allowed.
We learned how to quarry, drill and blast. Although we used feather-and-wedge method of rock removal as much as possible (to minimize chances of damage), blasting was normally mandatory.
We typically used Forcite 40, which we found to be a good general purpose explosive and usually loaded the holes lightly so as to crack the rock but not throw it to minimize damage to the pockets. It might take a full day of drilling to lay out a blast and I clearly remember not being able to open my hands fully without pain after a day on the plugger.
The amethyst at the Diamond Willow Mine had a complex history of formation, with the crystals first forming tight to the walls of the pockets and then later, probably due to more geologic activity along the fractured fault systems the plates of crystals collapsed into a jumbled mass. At some later time these pockets became filled with a stiff red clay. This history of formation is something of a mixed blessing. If the pockets had not collapsed the crystalline plates would have to be cut or otherwise chiselled off the walls making recovery much more difficult. But of course, because they are collapsed, the plates suffered nearly ubiquitous damage. (Another “fun” aspect of working in the clay filled pockets is that the clay is typically riddled with tiny, razor-sharp quartz shards… after a few weeks of that, your hands are in rough shape…)
Although we have not been back to the Diamond Willow for many years now, today it is still in production.
- Ian Nicklin
Thunder Bay Amethyst
Crystallized quartz in the Thunder Bay District is found in vugs and cavities of varying sizes, from 2 cm across to a cavity large enough that you can crawl in. Donald Elliott (1982) describes one pocket that was 15 x 3 x 2.4 metres in size (references are listed at the end of this post). Amethyst crystals from the Thunder Bay District are most commonly 1-2 cm in size, but larger crystals are also occasionally found. Rarely, very large crystals have been found – a crystal 61 cm across is reported in Elliott (1982).
Thunder Bay quartz crystals occur in many colours and shades, from colourless to smoky quartz, and the variety amethyst occurs in crystals from delicate pale lilac to a deep purple that can approach black. The lustre of Thunder Bay amethyst ranges significantly from the best of the brilliant, lustrous crystals at the Diamond Willow Mine (some of which look perpetually wet (!)) to crystals that are not bright and can even be fairly dull in lustre.
One of the most beautiful and distinctive characteristics of many Thunder Bay amethysts is the inclusion of red hematite (microscopic disks/spherules within the amethyst). The inclusion of red highlights, red zones, and even completely red amethyst crystals are all a classic look for Thunder Bay specimens.
The crystal morphology of Thunder Bay amethyst is basic, as most crystals exhibit only well-developed pyramidal faces. Prism faces are uncommon, and doubly-terminated crystals are rare.
Some specimens are entirely red, and some show distinct zoning – the crystal surfaces are red and amethyst is evident as an earlier phase growth.
One of the authors has always thought the completely red ones look like clusters of jasper crystals, if only jasper crystals existed. (Neither Ray nor Ian has ever contemplated the existence of jasper crystals – both agree that’s a great description of the intense tone of red.) Certain of the completely red crystals have been found to be comprised internally of zoned ametrine, underneath the red outer layer.
The best of the amethyst specimens mined by David and Ian Nicklin at the Diamond Willow Mine are remarkable, in part for their brilliant lustre and exceptional condition.
Labelling Thunder Bay Amethyst
The history of the amethyst discoveries and production of the past is helpful in understanding locality information, particularly for older specimens. it is also instructive for all specimens where the labelling has been vague. It is so common to see mineral specimen labels with “Thunder Bay, Ontario”, and no further information. Although “Thunder Bay amethyst” has actually occasionally been found right inside the city limits, the city of Thunder Bay is not the source of the Thunder Bay amethyst specimens on the contemporary mineral market. Similarly, it would be a feat today to obtain an amethyst specimen excavated in the silver mines of the area before the early 20th century. Unless a specimen is actually known to date to the early 20th century or earlier, specimens labelled “Thunder Bay, Ontario” (or, one sometimes sees “Port Arthur, Ontario” on pre-1970 specimens) are most likely from any of a handful of producing mines and properties – or possibly even any of a rather large number of prospects and additional known deposits – most of which are in McTavish Township, in an area beginning about 50 km northeast of the city of Thunder Bay. Absent specific locality information, the use of only “Thunder Bay” on a label should be considered to refer to the Thunder Bay District.
Thunder Bay Amethyst – Today and Future
Thunder Bay amethyst is among North America’s finest and is known by collectors around the world. These amethysts are contemporary classics for mineral collectors. Because the amethyst-lined vugs of any size naturally have collapsed during their history before anyone has found or collected their contents, excellent quality specimens will always be uncommon, hard to obtain and highly prized.
Amethyst has been found at many localities over a considerable area within the Thunder Bay District (localities up to 200 km apart) and mining continues today at a few properties. As Frank Melanson (2012) points out, thanks to our winters it is a short mining season, and thanks to the rugged terrain, access and access cost is always an issue, so it is difficult to mine Ontario amethyst profitably. And yet, the lure of the amethyst continues to inspire ongoing efforts, despite the economic hardships (and not to mention the black flies!). In Frank’s words, “for many, keeping the mines open was a labour of love.”
It is possible to personally collect amethyst in the Thunder Bay District, primarily on a fee-collecting basis, and also at other prospects and exposures. All of the authors have collected amethyst crystals in the Thunder Bay District. Most individual collecting is typically on the dumps, notably at the Amethyst Mine Panorama, but it is difficult to find collector-quality fine mineral specimens on the dumps. Other collecting is just a bit more involved, as Ian’s description conveys!
When amethyst was first encountered in the early silver mines of the nineteenth century, no-one would have foreseen the story of Thunder Bay amethyst as it has unfolded. Thanks to the later vision and pioneering efforts of Gunnar Noyes, Rudy Hartviksen and others, those first finds of amethyst would lead to the discovery of significant amethyst deposits and the preservation of spectacular amethyst specimens that now reside in museums and collections all over the world. It is unclear how many Thunder Bay amethyst mining ventures will be able to continue in the future, but it is likely that fine specimens will continue to be found, in very small numbers, relative to the amount mined. It is also likely that the best amethysts mined by David and Ian Nicklin will, for a very long time, be considered among the finest quality amethysts ever collected in the Thunder Bay District.
Many, different, beautiful amethyst specimens from this locality are available on both McDougall Minerals and David K. Joyce’s websites; click, here, on David K. Joyce or McDougall Minerals links to go directly to them.
Acknowledgements
Thank you to the Noyes family for their kindness and generosity, and for enabling the development of their deposit such that Diamond Willow Mine amethyst crystals will be enjoyed in collections worldwide for generations to come.
Thanks also to Tory Tronrud and the Thunder Bay Historical Museum Society for kind assistance and permission to share the Fort William mountain train photograph in this article.
References
Elliott, D.G. (1982) “Amethyst from the Thunder Bay region, Ontario” The Mineralogical Record. March-April 1982, vol. 13, no. 2.
Melanson, F. (2012) “Purple Rain: Thunder Bay Amethyst” No. 16: Amethyst, Uncommon Vintage. Gilg, H.A., Liebetrau, S., Staebler, G.A. and Wilson, T., eds. Lithographie, Ltd.
Vos, M.A. (1976) Amethyst Deposits of Ontario Ontario Division of Mines – Ministry of Natural Resources, Geological Guidebook No. 5.
Background
The Tanco Mine is a tantalum-cesium-lithium producer located in Southern Manitoba, Canada, east of Winnipeg. The pegmatite, which does not outcrop to surface, was originally discovered in the 1920’s during a diamond drill program.
Conditions were not right for commercial production until 1969 when Tantalum Mining Corporation of Canada Limited built a 500 ton per day tantalum concentrator was built on the site. Shipping of ceramic grade spodumene concentrate production began in 1986. Cabot Corporation acquired 100% of the operation in 1993. In 1996, the Cabot Specialty Fluids Division started producing cesium brine at the Tanco Mine.
The Tanco Pegmatite
The Tanco pegmatite is a “rare-element” pegmatite of the lithium-cesium-tantalum (LCT) type. LCT pegmatites are mineralogically differentiated from other types by the following:
The Tanco pegmatite is an excellent example of the complex type–petalite subtype of LCT pegmatite.
Geologic Setting
The Tanco pegmatite, situated at the western end of Bernic Lake, is an extremely fractionated, rare-metal, complex type-petalite subgroup, LCT pegmatite and is hosted by a late stage, subvolcanic metagabbro amphibolite. The age of the Tanco pegmatite is approximately 2.576 billion years (Cerny et al, 1996).
The pegmatite is blind or buried and only sub-crops in a limited area in the bottom of Bernic Lake. Based on many diamond drill holes, the pegmatite has a maximum length of 1,990, a maximum width of 1060 metres and is up to 100 metres thick. The total tonnage of the pegmatite is calculated to be approximately 25 million tones (Stilling, 1998)
It is felt that the pegmatitic fluids that formed the Tanco pegmatite were injected into a sub-horizontal joint set with vertical joints enabling the hydraulic “lifting” of the overlying block of metagabbro.
Pegmatite Zonation
Internally, the Tanco pegmatite is composed of nice discrete zones with different mineralization of economic interest –tantalum, spodumene, pollucite and rubidium –each essentially occurring in different zones.
Mining
Mining is carried out using the “room and pillar” method. The excellent ground conditions and the need to utilize selective mining because of the various ores recovered, were the reasons that this mining method was utilized. The “rooms” were originally 16metres square but are now set at 22 metres after years of experience, geotechnical work and careful design.
Mining is mechanized with two-boom jumbos performing most drilling. Occasionally, a single-boom Simba longhole drill is used, particularly in pillar reduction where geometry permits. Ore is mucked and transported using 5, 6 and 7 cubic yard scoop trams and a 20 ton truck. Ores are dumped into ore passes located throughout the mine and then transported by train to the shaft on a tramming level in four-ton Granby style cars. The ores are hoisted to surface via a four ton skip. Mine ventilation is downcast from surface using two fresh air raises. The mine exhaust up casts through the access decline. Air volume required to service the mine is around 5300 cubic metres per minute.
Mineral Processing
The concentrator is constructed on a peninsula of Bernic Lake beside the other mine buildings and offices. All of the ores are crushed down to ,12mm in size. The tantalum, spodumene and pollucite ores are then stored in separate fine ore bins.
Tantalum Processing The tantalum process involves a number of steps and types of equipment. Simply put, the crushed feed is ground to pass 2mm. The <2mm particles are then moved through a series of spiral classifiers, cyclones, tables, belts and filters to produce a concentrate that contains 35-38% tantalum oxides, 14-18% Tin oxide, 5-8% Niobium Oxide and 2-4% titanium oxide.
Tanco’s tantalum concentrates are shipped to Cabot Performance Materials’ facility in Boyertown, Pennsylvania for conversion to the titanium metal or tantalum compounds.
Tantalum is a very useful metal with unique properties. The major uses of tantalum are in the electronics industry and for cutting tools. High quality capacitors are the major single use for tantalum. Tantalum carbide is used in production of hardmetal alloys for cutting tools, mainly in Europe. Other tantalum alloys are important constituents of aero engines as well as in acid resistant pipes for the chemical industry. Tantalum pins are used for medical purposes such as hip-joint replacement, since tantalum is the only metal that is not rejected by bodily fluids.
Spodumene feed at the Tanco Mine is moved through a complex series of processes including heavy media separation, grinding, magnetic separators, cyclones, tables and driers. Concentrated products ranging from 5.00% to 7.25% Lithium are produced in the process.
Most spodumene, today, is used in the manufacture of glasses and ceramics. Lithia is a powerful flux and the lithia component of spodumene can have a dramatic effect on the properties of ceramics, glazes and glasses providing benefits to manufacturers of these products. Effects such as lower viscosity, faster melting and higher gloss enable manufacturers to sped up production, have less flaws (bubbles) and increase the ability to make more elaborate, attractive products.
The other major product made at Tanco mine is cesium formate. Pollucite ore is selectively mined at Tanco along with the tantalum and lithium ores. Tanco mine contains approximately 75% of the known world proven reserves of pollucite. The ore is crushed and ground to -12mm and then dry ground in a ball mill to powder form. With a series of acid/base reactions, the cesium is extracted from the pollucite ore and converted to a high-density cesium formate solution.
Cesium formate is a water clear, water soluble fluid with a specific gravity of 2.3g/cc (two and one third times the density of water). It is used in the oil drilling industry as a drilling fluid where the properties of low viscosity, high specific gravity and complete solution have significant benefits over traditional bentonite/barite drill muds in deep wells greater than 4,575m (15,000 feet!). The cesium formate eliminates formation damage which results in improved hydrocarbon flow from the reservoir in the long term. This means that more hydrocarbons can be extracted from the formation before stimulation techniques are necessary. Cesium formate has low toxicity to people and the environment which is an important added benefit.
Specimen Mineralogy
This section will be concerned with minerals that occur in well formed crystals and/or rare minerals that can be recovered as specimens. It will primarily deal with minerals that I have a first-hand knowledge of. There are many excellent papers on the mineralogy and geology of the Tanco pegmatite if you want greater detail about mineralogy. One in particular is: Cerny, P, Ercit, T.S., Vanstone, P. Mineralogy and petrology of the Tanco rare element pegmatite deposit, southeastern Manitoba, International Mineralogical Association, 17th General Meeting Toronto 1998, Field Trip Guidebook B6. The various minerals will be treated alphabetically.
This section is, presently, rudimentary but I will try and upgrade it as I learn more about the specimen mineralogy and geology of the Tanco Pegmatite.
Albite Albite is ubiquitous at Tanco mine. Normally it is massive to fine grained in many ore types. The spectacular “aplitic albite” which ranges from grey-blue in colour forms wondrous rounded aggregates in contact with massive quartz. Occasionally, well formed albite crystals are found in vugs in the…….zone. The crystals are colourless and often associated with tiny apatite crystals and cookeite.
Amblygonite This mineral occurs in very large crystals at Tanco but, unfortunately, not in fine crystals. It does occur in large rounded white crystals, sometimes with a yellow colour and usually with a montebrasite alteration rim.
Analcime is found in very well formed crystals in cavities in SQUI. The crystals are lithium-rich and lustrous showing the trapezohedral form.
Apatite is present in all zones of the pegmatite but rarely in good crystals. In cavities, it is often found fully or partially coating quartz crystals or the vug walls as beige microcrystals or smooth botryoidal coatings on quartz. Rarely, it is found in cavities as red-purple radiating/rounded aggregates of radiating crystals to 10mm or so in size.
Apatite is often seen as blue blebs, aggregates and rounded crystals throughout the mine.
Arsenopyrite occurs, occasionally, as well formed crystals and crystal aggregates at Tanco Mine.
Beryl The beryl at the Tanco mine, generally is a very white colour, sometimes with a yellowish cast. Beryl crystals at the Tanco Mine are usually simple hexagonal prisms terminated by a pinacoid. They are not generally very elongated compared to beryl crystals from other deposits but, usually do not have a length to width ratio greater than 2:1. Often, the crystals are tabular-hexagonal. In terms of size, beryl crystals at Tanco have been found up to 15cm in diameter and to 30cm in length. More commonly, they are in the 6-7cm diameter range or smaller. The crystals are usually found at the interface between albite and quartz in the Main Zone and are often associated with good grade tantalum ore. Occasionally, the pinacoidal faces of the beryl crystals have a cap or zone of tiny columbite-tantalite crystals on the pinacoidal faces.
The Beryl crystals at Tanco Mine are not uncommon but recovery of specimen-grade crystals is difficult. Because the crystals are always “frozen” in quartz, the quartz must somehow be separated cleanly from the beryl to reveal the full crystal. Most often, the quartz is slightly intergrown with the beryl crystal faces, holding the crystals fast and causing them to shear when an attempt is made to remove the quartz. Occasionally, the beryl faces are smooth and less intergrown with the quartz, enabling the clean removal of the quartz to expose the beryl crystals.
Bismuthinite is not a common mineral at the Tanco mine but does occur on occasion. It occurs as coarse, bright metallic cleavages in quartz albite
Lepidolite is common at the Tanco Mine, although it does not occur in good crystallized specimens. The lepidolite is most commonly in large masses of fine-grained, interlocking crystals. These masses are very compact and actually make excellent lapidary material since they cut well and take a very nice polish. Some local artisans make very nice carvings out of this purple-coloured rock.
Lithiophosphate This is a rare mineral at the Tanco mine but it has been found in excellent, colourless, cleavages.
Lithiophylite is not a particularly common mineral at the Tanco mine but occasionally occurs as large rounded crystals in quartz/albite.
Microlite is another Tantalum-bearing oxide that occurs at the Tanco mine, and in some zones is considered an ore mineral. The only good crystals that I have seen have been colourless, micro-crystals coating titanowodginite crystals in vugs filled with calcite, where the calcite has been leached out with weak acid.
Microcline Microcline is a common feldspar at the Tanco mine but it occurs in UN-commonly sized crystals. As you can see in the image on the right, the crystals of microcline can easily attain lengths of 3-4 metres in size!
Muscovite This Mica Group mineral occurs fairly commonly at the Tanco Mine, most interestingly as rounded “curvilinear” aggregates that mine workers call “ball pien mica”. When in this habit, the muscovite resembles silvery to purple-silvery rounded crystals that do resemble the rounded end of a ball-pien hammer! This muscovite has a high Lithia component and is often referred to as lithian-muscovite.
Petalite is relatively common at Tanco Mine but not in good crystallized specimens.
Pollucite The Tanco Mine is the worlds greatest economic concentration of cesium, due to the very large zone of massive pollucite in this amazing pegmatite. The pollucite is massive, often showing a layered look with clear bands alternating with milky. Unfortunately, crystals of pollucite are not found at the Tanco Mine, except perhaps as micro crystals.
Quartz There is a LOT of quartz at the Tanco Mine particularly in the very large Quartz Zone. Generally, the quartz is massive and white but, occasionally, there are vugs which contain very well formed crystals up to 30cm or so in size. They are usually clear and colourless but can be fairly “smoky, as well. Usually the quartz crystals are associated with drusy pyrite crystals and tiny apatite crystals. Often many of the quartz crystals are actually shards of crystals that appear to have continued to grow after some tectonic event shattered them in the vug.
A very interesting form of quartz at the Tanco mine is the “cleavable” or, actually, “cleaved” quartz. Occurs which is cut by cleavage planes and presents an image of a mineral more like calcite or some other mineral with diagnostically good cleavage. The geologists at the mine love to show this kind of quartz to mineralogical experts and stump them when they are challenged to determine what this unusual mineral is! People are just not used to seeing cleavage in quartz. I expect that the quartz that exhibits this cleavage was thermally or mechanically shocked somehow for it to have these cleavage planes developed so well.
Simpsonite Here is a rare one! In places, at Tanco mine, simpsonite is an ore mineral of Tantalum. It occurs as browny-beige rounded crystals embedded in albite, occasionally as well formed crystals.
Spodumene “Spod” is a key ore mineral at Tanco Mine. While Spodumene occurs in spectacularly large crystals, embedded in quartz or albite, nice “specimen” type crystals rarely occur. Occasionally, smaller, well-formed, terminated crystals occur embedded in quartz and these can make fine specimens. Another interesting occurrence is in vuggy squi where small, gemmy, cm-sized blades of spodumene occur in cavities with analcime.
Tantalite This mineral is one of the main ore minerals of the Tantalum. It occurs in several of the zones of the mine from sparse concentrations to very rich, high-grade zonatons. Generally crystals are small but, on occasion, large prismatic crystals are mined. Some nice specimens of tantalite crystals have been recovered over the years but nice ones are rarely encountered, in recent times.
Tourmaline is common at the Tanco Mine but does not often occur in collectable crystals. The wall zone has lots of black crystals embedded in the feldspar but the crystals are tightly held and rarely can be freed from the other enclosing minerals.
On occasion, very nice pink crystals of tourmaline are encountered embedded in fine grained lepidolite. Specimens of this material can make very attractive specimens.
Tryphylite does not occur in well formed crystals at Tanco but does occur in large, dark yellow crystals embedded in other minerals.
Wodginite Group Several minerals of the Wodginite group have been found at the Tanco Mine. Most interesting in recent times are the excellent titanowodginite crystals found embedded in white beryl and smoky quartz in the “beryl pit” in the main zone. The Tanco mine is the type locality for titanowodginite. The crystals occur as very well formed, doubly terminated, single, wedge-shaped crystals and, more rarely, v-shaped twinned crystals. The single crystals are usually in the 3-4mm size range while the twinned crystals can range up to 20mm in length (rare), making these the largest crystals of this mineral in existence. The crystals are black, often with a curious light iridescent sheen to them.
Wodginite also occurs in radiating clusters embedded in quartz and albite. The wodginite is dark brown and shows a distinctive radiating crystal structure.
Wodginite group minerals are key ore minerals at the Tanco mine. Blobs, patches and particles of wodginite group minerals are common in certain parts of the mine but have little interest as mineral specimens.
By David K. Joyce, Newmarket, Ontario and Roger Poulin, Val Caron, Ontario
Introduction
The Sudbury Mining Area is one of the most prolific metal mining areas in the world. The discovery and development of the mineral deposits are not well known outside of Canada, despite the huge amount of wealth that has been generated by the metal recovery, the contributions to mining technology and, for mineral collectors, the great minerals that have been discovered there. This article is intended to offer a slightly different view of the Sudbury mining area, skewed towards a better understanding of the mineralogy and geology of the area.
History
Before the discovery of minerals in the Sudbury area, the area north and east of Lake Huron’s Georgian Bay was an area mostly used for trapping and logging, as well as subsistence hunting, fishing and foraging by the Ojibway people.
The history of interest in the minerals of the area seemed to start in 1856 when a land surveyor, W.A. Salter, noticed a very strong magnetic anomaly while running survey lines. Salter was running a meridian north from his baseline when he “discovered considerable local attraction, the (compass) needle varying from four to fourteen degrees westerly”. Salter shared his findings with A. Murray of the Geological Survey of Canada, who examined the gossanous rocks near Salters meridian line. Assays of samples returned 2% copper and 1% Nickel but the deposits were too low grade and too remotely located at the time to generate any enthusiasm from contemporary miners. That meridian line ended up being only two hundred metres or so west of the future Creighton open pit mine of INCO Metals Ltd! The two surveyors reported their anomaly findings to the provincial government but their report raised no interest (1917 Royal Ontario Nickel Commission, Pg 20-28). The mining industry was practically non-existent, at the time, in Ontario, or Canada, for that matter. There were simply very few people in Canada who would or could appreciate the potential significance of such an anomaly.
So, as sometimes happens, the eventual, actual re-discovery of more economic mineralization at Sudbury turned out to be a fortuitous incident.
The Dominion of Canada had only come into existence, in 1867. Famously, after Confederation, the government of Canada moved to fulfill terms of confederation with western provinces to build a railway that would run from coast to coast to tie the various provinces and territories, that formed the new country of Canada, together. Such a railway would “open up” the land for development, make it easier for citizens and immigrants to move about and make it easier to administer the new country. Many of the existing provinces and territories had stronger north-south ties to the USA, than they did with the other British colonies-turned provinces. So the railway was begun as one of the largest country building projects in Canadian history.
In 1883, work on the new Canadian trans-continental railway was well underway. During that year, when work crews were blasting cuts through rock for the railway right-of-way, just west of the current location of Sudbury, they encountered a rusty, dense rock. This mineralization, first noted as important by a blacksmith on the railway, Thomas Flanagan, was the first mineralization that spurred interest in further exploration. Land in the vicinity of the discovery was purchased by brothers William and Thomas Murray, Henry Abbott and John Laughrin for $310.00 or $1.00 per acre, the going rate, at the time, for mining concessions.
The discovery led to many other prospectors and developers coming to the area. Prospectors such as Thomas Frood, Francis Crean, Henry Totten and James Stobie showed up and, eventually, all had mines named after them.
The small operations had a difficult time being successful due to lack of capital and the difficult metallurgy of the ores. A turning point came when a capitalist/industrialist from Ohio, Samuel J. Ritchie formed the Canadian Copper Company in 1886 and purchased the Murray, McAllister, Copper Cliff, Stobie and Creighton Mines. The Canadian Copper Company made the Copper Cliff Mine into the first truly successful mining operation. Murray developed the Flanagan/Murray discovery into the Murray Mine, initially as a copper mine. At that time, copper was the commercial driver and nickel was of little interest.
Another deposit was discovered in 1887 and became the Vermilion Gold Mine. It was an unusual deposit for the area since it had significant amounts of native gold and platinum plus a high-grade nickel-copper orebody. Many prospectors flocked to the area to find similar deposits but were not successful.
Canada had no mining or metallurgical infrastructure or expertise, at that time. Early ores were shipped to and processed at the Orford Refinery in New Jersey, USA. Some of the copper ores were very difficult to process due to the presence of “Devil’s Copper” or kupfer-nickel, so named by German miners of old, who had also had difficulty dealing with that impurity metal in their copper ores. There was little use for nickel at the time and it was a nuisance in the way of recovering the more useful copper. The Canadian Copper Company struggled along recovering copper the best it could.
In 1904, the Mond Nickel Company was formed and purchased the Garson, Victoria and Levack deposits to supply its metallurgical facilities. (I remember working in the engineering department at Levack Mine in 1975 and seeing and using old Mond Nickel Company linen drawings of the early mine workings. DKJ) The founder, Ludwig Mond, a chemist from Germany, had developed a process to refine nickel, which was becoming a metal in demand, largely for armament production and industrial applications. The burgeoning growth of industrial development in the developed world, the build-up of military equipment and the eventual breakout of WW I enabled the Mond Nickel Co. to expand and prosper. The Mond Nickel company shipped its matte (NiS/CuS mixture) to its facilities in Wales for further processing and refining.
Thomas A. Edison recognized the usefulness of nickel and came to Sudbury in 1901 to try to try and develop a deposit to supply the factories for his light bulbs. He was not a mining man, however and was not successful.
In 1902, the Canadian Copper Co. merged with the Orford Refinery Co. to accomplish vertical integration. The new company was called the International Nickel Company. That company proceeded to develop a new refinery on the north shore of Lake Ontario in an effort to make processing more efficient. As well, the development of “Monel Metal”, a very useful nickel-steel alloy, spurred the success of the company. Production reached a peak during WWI but after the armistice, production at Sudbury area mines ground to a near standstill. Nickel had become the main metal of commercial interest in the Sudbury operations and, at that time, there were few peace-time uses for nickel.
The year 1928 was a formative year in the history of the Sudbury area. During that year, The International Nickel Company merged with Mond Nickel, to create a future colossus in the world of nickel.
That same year, another American entrepreneur, the famous Thayer Lindsley, formed Falconbridge Nickel Mines Limited to develop the very deposit that Edison had failed to exploit. Falconbridge Nickel was, subsequently, highly successful for many decades from its base in the Sudbury mining area and throughout the world, not just in nickel and copper but in many other metals. Lindsley was a mining giant and a genius.
The Sudbury nickel mining area had difficult times until the mid-1930’s when the world started re-arming. Unfortunately, the early history of success in the Sudbury area was largely tied to military escalation and wars. So it was that International Nickel and Falconbridge Nickel supplied nickel to strengthen steel for the world wars, Korean War, Cold War, Vietnam War and the building of armies and strategic stockpiles by the USA and other counties.
After WWII, many other uses of nickel for more domestic, peace-time consumption were identified. Stainless steel became the norm for many kitchen fixtures, automobile and appliance uses. Sudbury prospered and grew over the years with various ups and downs that paralleled general economic conditions.
As previously mentioned, International Nickel Company and Falconbridge developed mining operations elsewhere in the world and Canada’s dominance as THE world nickel supplier declined. Lateritic nickel deposits, especially developed by those two companies in Dominican Republic, New Caledonia and Indonesia have reduced Canada’s dominance in production of this metal, although it is still an important player.
Eventually, the International Nickel Company of Canada became INCO and the Falconbridge Nickel Mines Ltd. became Falconbridge Limited. The two were at times, fierce competitors and, at other times, business associates that had mining operations on the same orebodies and side by side smelter complexes and that cooperated on matters of efficiency and community development. At times they made overtures to merge but could not overcome the rivalries and ego-driven managements. If the two had merged years ago, a world-class mining/smelting colossus would have resulted. As it turned out, the inability to merge, left them both as relatively vulnerable, relatively small metal producing companies on the world stage. In 2005, Falconbridge merged with Noranda, another Canadian mining/smelting company and the new entity was called Falconbridge. Eventually, in 2006, after bidding wars by INCO, Phelps-Dodge and Xtrata, Falconbridge was taken over by Swiss-based metal company Xtrata, which was later absorbed by its Swiss parent company, metals-giant Glencore.
INCO met a similar demise. It had waited just too long to merge with Falconbridge to form a strong, robust international-scale integrated metals producer. In 2006, Phelps-Dodge, Teck Corp and CVRD of Brazil went after INCO in a series of takeover bids. Eventually Companhia do Vale Rio Doce (CVRD) triumphed and INCO was no more. CVRD changed its name to Vale and the former INCO operations, all fall under that name, now, and are controlled from Brazil.
Interestingly, the metal that started it all is not produced at Sudbury as a finished product, any longer. Copper concentrate is produced at Sudbury but then shipped to Noranda for processing into copper metal. The two big metallurgical complexes of Vale and Glencore continue to operate. Pure nickel metal is produced at Vale’s facilities but Glencore accomplishes final nickel refining at the old Falconbridge refinery, Nikkelraffineringsverk, in Kristiansand, Norway.
Other mining companies operating or recently having mining operations in the Sudbury area are KGHM International Ltd. and Wallbridge Mining Co. These companies have their ores milled and processed by Glencore or Vale on a custom milling-smelting basis.
The Sudbury mining area has produced immense wealth! Here is a tally of one estimate of production from this amazing geological structure (www.Sudbury.com, June 18, 2008):
1.7 billion tonnes of ore containing:
40 billion pounds of nickel
36 billion pounds of copper
70 million ounces of platinum and gold
283 million ounces of Silver
At recent metal values, this represents a value approaching $500 billion produced from over 60 significant mines, over 130+ years! Importantly, though, it is estimated by most that the Sudbury area will be producing metals for the next 100 years or more.
Environmental Impacts: Why the "moonscape" reputation?
The Sudbury Mining Area is often known for its “moonscape” like landscape rather than for the positive impacts it has had on the economy. The main pollutant that has emerged from the Sudbury mining and smelting processes over the years is sulphur. The copper, nickel and other metals are tied up in high sulphur-content ores and, in order to recover the metals, the sulphur needs to be separated from the metals. The early methods to do this were effective but devastating to the environment and, probably, to the health of workers. Prior to 1929, gigantic piles of cordwood up to 2km long(see Figure 5) were laid out and ore was piled on top of the cordwood. The resultant ore-on-wood arrangement was set on fire and allowed to burn/smoulder for months in an effort to drive off as much sulphur as possible before shipping to the smelter. The sulphur was driven off and clouds of sulphur dioxide smoke drifted around the countryside killing all vegetation in the surrounding hills and valleys for miles around. Of course, the loss of vegetation resulted in erosion of the soil. For many decades, the landscape around Sudbury did actually resemble a moonscape! In fact, in the early 70’s NASA had sent some of its astronauts to spend time in the Sudbury basin, as a precursor to conditions they would encounter on the moon.
A more modern smelter complex was built and used after 1929 to smelt the ores but the sulphur dioxide still affected the land around Sudbury. Temperature inversions would cause clouds of sulphur gasses to descend on Sudbury and area, causing further environmental damage, paint to peel from cars, corrosion and who knows what effect on peoples’ health. The answer to the pollution in the 60’s was for INCO Ltd. to build a giant smoke stack, the 381 metre (1250 foot) “Superstack” to take the sulphur gasses higher up to drift away well above the city of Sudbury. The idea was that the gases would become diluted enough before they reached earth again that they would have little effect. It certainly worked for the Sudbury area but “downwind” ph levels in lakes and the environment drifted downward somewhat. When approaching Sudbury by land or air the dominant feature of the skyline was the Superstack with a giant plume of gases coming out of it.
Over the years, the two smelting companies in Sudbury, Inco and Falconbridge, now Vale and Gencore, have spent billions of dollars to actually reduce the amount of sulphur and other gasses that are released to the atmosphere. As a result, now, there is only a barely perceptible plume, if any at all, emanating from the Superstack. In fact, the Superstack has become obsolete. It is no longer needed. It is planned to stop using and tear down the Superstack in the coming years.
What has happened to the sulphur gases? Some percentage of the sulphur has always been captured and converted to sulphuric acid. Now almost all of it is converted to sulphuric acid which is an important chemical in many processes, especially fertilizer manufacture.
The mining companies, local governments and volunteers have spent much money and time re-building, neutralizing and re-vegetating the environment around Sudbury. If you visit Sudbury today, with few exceptions, you would not think of a moonscape. The city is now well forested with more lakes within the city boundaries than any other city in North America. It is a beautiful place again! Well, there are a few places where the barren blackened rocks still dominate but they are fast disappearing as vegetation and forest become re-established. NASA astronauts will probably not visit Sudbury for moonscape training in the future!
Geology
Much has been written about the Sudbury Basin (AKA Sudbury Structure or Sudbury Nickel Irruptive or Sudbury Igneous Complex(SIC)). We will present a summary here, not an in depth treatise. Detailed discussion papers can be found in the following publication:
1984, Ontario Geological Survey, Special Volume 1, “The Geology and Ore Deposits of the Sudbury Structure”.
The Sudbury Structure is a major geological feature on the geological map of Ontario and is located in the Canadian Shield. Originally, geologists believed that molten rock was forced up through the earth’s crust and spread out into a lopolith type of intrusive structure when it encountered the surface sediments. The heavy minerals settled to the bottom of the molten magma forming the nickel-copper deposits that we know today. Other geologists speculated that the Sudbury Structure was a large volcanic caldera.
In the 1960s, a scientist by the name of Dr. Robert Dietz, theorized that a giant meteorite impacted the earth’s crust, breaching it, allowing nickel-rich magmas to intrude close to surface and causing the Sudbury Impact Structure.
The Sudbury Impact Structure is, in fact, a bolide impact structure and is the third largest known crater or “astrobleme” on the surface of the earth. About 1.849 billion years ago, a very large object left outer space and impacted the earth and formed a large crater, the “Sudbury Structure” which, originally, is estimated to have been a circular structure 200km across. Through erosion and various tectonic forces, the remnant of the structure is now reduced and distorted to about 62 by 30km in size.
The early research concluded that the bolide was a meteor and this has been the accepted type of object that created the crater for several decades. Some recent research, analyzing rock types and elemental distributions, concludes that the crater causing object was a comet. Whatever the object was it was BIG and made a large impact on Earth’s crust.
The “fallout” from the impact of the bolide would have been catastrophic. It is estimated that debris from the impact was thrown as far away as 800km and, indeed, rock fragments from the impact have been found as far away as Minnesota. It is also thought that dust and smaller debris were dispersed globally but, of course, have long disappeared due to erosion.
For many years, it was difficult to consider or prove that the Sudbury Structure was, in fact an astrobleme. The 1.85 billion years of deformation and erosion masked the true origin of the structure. Scientists eventually recognized properties and characteristics of rocks in and in the vicinity of the structure that firmed opinions that, in fact, the structure was caused by some sort of impact. Key evidence was the presence of shatter cones, strain features in rocks surrounding the impact, and rocks that were recognized as fallback breccias; rock fragments that were thrown into the air and that fell back to earth and subsequently consolidated into a breccia-like rock. In addition, melted rock formed glass which filled open cracks as dykes beneath the crater. This pseudotachylite rock is known locally as the Sudbury Breccia. These same features can be seen at other major impact sites, both modern and ancient in other parts of the world.
The base of the (SIC) crater forms a layer of brecciated rocks consisting of rock types present from local Proterozoic and Archean rocks. (>2.1ma) This brecciated unit is locally called Granite Breccia and forms the footwall of the crater. The main rock types present are; granite, granite gneiss, gabbro and basalt. Mafic norite also can form breccias layered on and or mixed within the granite breccia. This rock type is termed Sublayer in Sudbury. These two breccia types are the hosts for the copper-nickel orebodies that Sudbury is famous for. Below and at the footwall contact, quartz diorite dykes form concentric and radial dykes rich in copper-nickel-(Pt-Pd-Au) orebodies. Sudbury Breccia occurs as dykes and dyke swarms within the brecciated footwall rocks and can host the rich copper-nickel-(Pt-Pd-Au) footwall orebodies found in Sudbury.
The Sudbury Igneous Complex is the main mineral-bearing part of the Sudbury structure and is considered to be a layered impact melt sheet. That is, when the impact occurred, the basin of the crater filled with a pool of liquid rock composed of mafic norite, felsic norite, quartz gabbro and granophyre from the bottom and up. Only the mafic norite contains sulphides in this group of layered rock types.
Above this unit, the Onwatin Formation is represented by siltstone and at its base, Cu-Zn-Pb-Au mineralization is associated with chert-carbonate deposition. Anthraxolite (hydrocarbon) veins and strong pyrite mineralization is also present. The former Vermilion and Errington mines are examples. This mineralization occurred over time as the SIC lost its heat energy. The very top of the SIC is covered with sandstones of the Chelmsford formation which have a Bouma sequence type of bedding which suggests the SIC was once buried by sediments under an ancient ocean.
Olivine diabase dykes (1230ma) intrude and cross cut the SIC striking north-south and east west. The dykes are vertical and can be 30m wide. From time to time, the dyke contacts can form open fractures containing sulphide, silicate or carbonate crystals.
Deformation is prominent within the SIC structure due to the South Range Deformation Zone which has sheared and displaced all the rocks of the south half of the crater in an average east-west direction. Rare calcite-marcasite, sphalerite and galena can be found in some of these late shear zones.
For many years, it was thought that the only valuable mineral deposits occurred in the Sudbury Igneous Complex as massive or disseminated Cu-Ni sulphide deposits in the granite Breccia Sublayer. In the last couple of decades, though, PGM-Group metal-rich deposits with Cu-Ni have been located in the footwall rocks of the structure to depths of 500m below the SIC contact.
Minerals of the Sudbury Structure
The SIC mineralogy can be divided in 2 distinct categories; The contact Granite Breccia- Sublayer type and the footwall Copper Zone type. Sulphide minerals of the contact ore zones consist of disseminated blebs, breccia fillings, massive veins and irregular bodies. In general, the dominant minerals present are: pyrrhotite, chalcopyrite, pyrite and pentlandite. The Footwall orebodies are usually found near or in Sudbury Breccia vein swarms as disseminated blebs, irregular veinlets and large massive veins several meters thick. Chalcopyrite is the main sulphide and contains, cubanite, pentlandite and minor pyrrhotite, cubanite, bornite, millerite and a variety of microscopic grains of Pt, Pd, Ag, Au, Bi, Te minerals.
(Comment from the Author (DKJ)
When I worked in Sudbury, I saw very few collectable mineral specimens in the various mines. There are massive and disseminated sulphide minerals EVERYwhere but minerals that are “collectable” are relatively rare. The orebodies are mostly massive sulphide deposits mined by bulk mining methods. These types of orebodies and mining techniques are not all that productive or amenable to recovering mineral specimens. Since the modern mining methods are highly mechanized, the ore is often only accessible at stope drawpoints and the ore in the drawpoints in covered with sulphide/rock sludge. It is difficult to see any minerals unless you get a chance to wash down the faces or the muck in the drawpoints. Well crystallized minerals are there, though, and over the years I have come to appreciate what is available through geologists and miners; cubanite crystals, sperrylite crystals, large masses of cleavable millerite, pentlandite crystals “frozen” in pyrrhotite, rare arsenides, cobaltite crystals, native silver in bornite plus many accessory minerals that can be well crystallized.)
Anthraxolite
Common in the lower Onwatin member of the S.I.C. as veins. Also found in the Vermilion and Errington Mines associated with the sulphides in calcite.
Aragonite
Aragonite occurs in limited occurrences in the Sudbury Structure. Some very long crystals, associated with pyrrhotite and cubanite were collected at the Strathcona Mine.
Fluorapophyllite
Fluorapophyllite occurs in the N-W tension fractures that cut through the Sudbury Structure.
Arsenohauchecornite
The Vermilion Mine, in the south-west of the Sudbury Basin, is the type locality for this rare mineral. Excellent crystals have been recovered, in the past but the location has now been largely rehabilitated and it is difficult to recover any interesting mineral specimens. Arsenohauchecornite crystals up to 11mm have been recovered in the past. Usually, they are embedded in pyrrhotite and chalcopyrite, at the Vermillion Mine.
Bornite
Bornite is relatively uncommon in the large massive sulphide deposits and disseminated sulphide deposits that have been the source of most of the metals in the Sudbury Basin. It has been found more commonly in the smaller, high-Cu-Ni-pgm footwall deposits, particularly in the northwest rim of the Sudbury Basin.
Calcite
is not a significant component of the orebodies but can be a significant component of later stage veins, olivine-diabase dykes and open faults cutting some deposits. On occasion, very good crystals have been recovered to 19.0cm.
Chalcopyrite
Chalcopyrite rarely occurs in significant crystals in the Sudbury ores. It is the major source of copper in all types of ores and many, many millions of tonnes of chalcopyrite have been mined in the Sudbury Basin over the past 130 years.
Cobaltite
The Sudbury Basin ores are a significant source of cobalt metal that is recovered as a by-product of nickel smelting and refining. Although the bulk of cobalt content of the Sudbury ores is derived from cobalt in solid solution with nickel in pentlandite, some of the cobalt content of Sudbury ores is derived from cobaltite gersdorffite and other cobalt minerals in the ores. Sharp cobaltite crystals up to 13mm in size have been recovered from the Sudbury Basin, usually embedded in massive sulphides such as chalcopyrite and pyrrhotite.
Copper
Native copper occurred only at the Vermillion Mine in Denison Township, in flat, dendritic crystal groups to 5mm in rock fractures.
Cubanite
Cubanite is thought to be a significant portion of the make-up of the Sudbury Basin ores although it is difficult to quantify. Polished sections of copper ores often show lamellae of cubanite in chalcopyrite in the high Cu-Ni-PGM and massive sulphide deposits. Since it is difficult to visually distinguish cubanite from chalcopyrite in rough ores, the cubanite is often un-noticed.
Excellent crystals of cubanite have been found at the Strathcona Mine, in the 1970s by Mr. Ron Lee, including some very large ones, up to 45mm in length. The cubanite crystals at Strathcona Mine were in cavities on the 2500-2600 levels associated with calcite and pyrrhotite crystals in a large horizontal fracture, near an olivine-diabase dyke.
Galena
Galena occurs in late north-south striking tension veins that cut through the SIC. The veins are 1 to 10cm thick and sometime contain calcite, marcasite, sphalerite and galena crystals. These are more common in the South Range mines.
Gersorffite
Gersdorffite as octahedral crystals and massive mineralization have been noted in the arsenic-rich zones of SIC orebodies, particularly at Garson, Falconbridge and Frood mines. Crystals of gersdorffite have usually been up to few mm.
Gold
Considerable gold has been recovered from the Sudbury ores, over the years, primarily as a by-product of copper recovery and refining. This is largely due to the presence of fine particles of electrum, a natural alloy of silver and gold. Native gold is rarely seen in the Sudbury basin with one exception, at the Vermilion Mine. This mine was precious metals rich and was operated as, largely, a precious metals metals mine. Significant native gold occurred in the Vermilion Mine surface gossan, primarily as sheets and masses in sulphide and carbonate fractures in the host rock.
Magnetite
Magnetite is ubiquitous in the Sudbury ores. It can often be seen disseminated in massive ores as individual, rounded crystals. Really well crystallized specimens have not been recovered.
Marcasite
Marcasite occurs in late north-south striking tension veins that cut through the SIC. The veins are 1 to 10cm thick and sometime contain calcite, marcasite, sphalerite and galena crystals. These are more common in the South Range mines.
Millerite
This mineral is usually found as acicular crystals in most world occurrences. Acicular crystals have been recovered in the Sudbury deposits, as well, particularly at the McLennan Mine, associated with siderite.
Of particular interest, though are the large cleavable masses of millerite that occur in some orebodies, particularly the footwall orebodies such as at Levack, McCreedy and Strathcona mines. Cleavage planes up to 16.5cm across have been noted, which must represent some of the largest millerite crystals ever! Such cleavages are usually embedded in massive chalcopyrite.
Nickeline
Nickeline is usually only present as massive mineralization in arsenic-rich zones of Sudbury deposits, particularly at deposits in the south S.I.C. No crystals of significance have been found to-date.
Pentlandite
Considering the vast tonnages of pentlandite that have been mined in all ore types and processed into nickel metal, at Sudbury, there are no well-formed crystals and anything resembling a crystal rare. It is easy to see small crystals (eyes) of pentlandite embedded in pyrrhotite in higher-grade, massive ores because of the relatively good parting or cleavage that reflects light well. Rarely, individual crystals of pentlandite will form “balls” of pentlandite up to 40mm diameter embedded in chalcopyrite, and other sulphides.
Pyrite
Pyrite is common in the Sudbury District ores but, again, rarely in good crystals. Occasionally, interesting, groups of curved crystals are found in open areas in fault mineralization. Most of the time, the crystals are octahedra up to 30mm, embedded in pyrrhotite and or chalcopyrite. The bulk of the pyrite occurs as grains and thin coatings around pyrrhotite.
Pyrrhotite
Pyrrhotite is ubiquitous in the ores of the Sudbury district and is the major sulphide composing the massive and disseminated ores in the main deposits. Pyrrhotite is rarely recovered in good crystals. It is usually found as massive and disseminated mineralization associated with chalcopyrite, pentlandite, magnetite and gangue mineralization. One massive orebody at Strathcona Mine contained and area with large, enmeshed hexagonal crystals to 20cm.
Quartz
Quartz is a common vein filling in the Sudbury ores but does not often occur in specimen quality crystals. Quartz mostly occurs only as crystals 1-5mm in size.
Silver
Silver occurs in quantity in solid solution, particularly with copper minerals. The copper refineries in the Sudbury District have produced hundreds of millions of troy ounces of silver as a by-product of electrolytic copper refining over the decades. Specimens of native silver or silver minerals are relatively rare, however. One notable occurrence was in a copper-precious metals rich “footwall” deposit at Strathcona Mine where veinlets of native silver were noted cutting through massive bornite and millerite. Superb specimens of “leaf” and “plate” silver, to 35.0cm across in bornite, similar to those from La Mina San Martin, Xacatecas Mexico, somehow survived the mining process.
Sphalerite
Sphalerite occurs in late north-south striking tension veins that cut through the SIC. The veins are 1 to 10cm thick and sometime contain calcite, marcasite, sphalerite and galena crystals. These are more common in the South Range mines.
Sphalerite is also found as fine-grained mineralization, associated with fine-grained galena and gold at the Vermillion and Errington Mines in the Onwating formation.
Sperrylite
Sperrylite Crystals have been found at a number of Sudbury Mines in some quantity but the best specimens have been recovered from the Vermilion, Frood and Broken Hammer Mines.
The Vermillion Mine is the type locality for Sperrylite. A Sudbury chemist, Francis L. Sperry, identified the new compound and in 1889 the mineral Sperrylite was published as a new species. Many, many specimens of sperrylite crystals, mostly embedded n chalcopyrite, have been recovered by geologists and mineral collectors over the years from old mine dumps on the property. These dumps have been re-worked for the precious metals content and the original site of the mine has now been largely rehabilitated with very little to be found now.
The Frood Mine was a huge, operating, underground mine for the past century and access to the mine workings and dumps has not been possible. Regardless, some sperrylite crystal specimens have been recovered and preserved by geologists in precious metals-rich areas of the mine, at various times over the years.
The Broken Hammer Mine was a relatively new and small addition to the past producing mines of the Sudbury District. The deposit was discovered in 2003 and eventually became a small operation producing precious metals-rich copper-nickel ore that was concentrated/refined by a custom mill/smelter. In its short lifetime, the Broken Hammer Mine produced some excellent sperrylite crystals, first from a bulk test-mining of ore and then from a 1.5 year production span. Interestingly, sperrylite crystals from this operation occurred differently from those at other Sudbury District mines. The sperrylite crystals at Broken Hammer Mine were often embedded, not only in sulphide minerals but also in silicate mineralization, usually epidote and/or quartz.
Sulphides: Acanthite, Chalcocite, Hawleyite, Polydymite, Stibnite, Talnakhite, Valleriite, Violarite(tl)
Elements: Bismuth, Electrum
Metallic Te, BI, As Sb: Altaite, Argentopentlandite, Breithauptite, dyscrasite, empressite, galenobismuthite, hessite, mackinawite, maucherite, parkerite(tl), schapbachite, skutterudite, tetradymite, tellurobismuthite, tellurohauchecornite
Platinum Group: froodite(tl), insizwaite, kotulskite, merenskeyite, mertierite, michnerite(tl), moncheite, niggliite, palladian melonite, stanopalladinite, sudburyite(tl)
Other: akaganeite, ilmenite, lawrencite
The majority of the rare minerals listed above were identified from samples collected in the copper rich portions of the various orebodies around the SIC. Copper-nickel massive liquid sulphides can be mobile at temperatures as low as 300C. For this reason a variety of elements such as Au, Ag, Pt, Pd and others were able to differentiate from the contact orebodies and be deposited in favorable structures below the contacts of the SIC and into most of the quartz diorite offset dykes.
Acknowledgements
Thank you so much to friends and colleagues who allowed us to photograph their specimens or to use photographs of specimens in their collections, including Gil Benoit, Tim Jokela, Joe D’Oliveira, Ed and Ruth Debicki, Rod and Helen Tyson, Reiner Mielke, plus Dr. Kim Tait and Ian Nicklin, of the Royal Ontario Museum.
We appreciate being able to use the great photographs of Broken Hammer Mine sperrylite photographs by Michael Bainbridge.
Thanks to Dr. Terry Wallace for allowing us to access the graphics of the evolution the Sudbury Impact Crater by Chuck O’Dale.
All photos by D.K. Joyce unless noted.
References and Bibliography
The Geology and Ore Deposits of the Sudbury Structure. E. G. Pye, A. J. Naldrett, and P. E. Giblin 1984 Ontario Geological Survey Special Volume 1
Harvest From the Rock –A History of Mining in Ontario. Smith, P. , MacMillan of Canada, Toronto, Ontario, 1986
On The Track of the Elusive Sudbury Impact: Geochemical Evidence for a Chondrite or Comet Bolide, Petrus, J.A., Ames D.E., Kamber B.S., Terra Nova, Volume 27, Issue one.
I feel honoured to be associated with and very familiar with Sudbury after many years of working on various project and commercial endeavours.
Levack Mine
I was fortunate to land summer employment in the engineering office of the old Levack Mine, for INCO back in 1975. In those days, Levack Mine was a full mining/milling complex and was in transition from old, labour-intensive mining methods such as “under-cut and fill” and “cut and fill” to more modern methods such as blasthole stoping and vertical retreat mining. The first “vertical crater retreat mining” done anywhere, was done at the Levack Mine in rib pillars. I learned a lot! My job was to be a surveyors’ helper and we went underground each day to survey the advance of development headings and the excavation of stopes. As well, we surveyed in the lines to direct miners on direction and limits of the various blasted excavations. After surveying underground each morning, it was up to surface on the cage, shower, eat lunch and do survey calculations, calculate miners’ bonuses, update drawings and work on simple engineering projects. It was a great job!
I lived in a bunkhouse on Copper Rd., in Levack, that summer, amongst various miners and mill-men. There were a couple of my classmates also living there and we hung out together when not working. I played baseball for “Levack Meats” sponsored by the local butcher shop. Playing rugby for the Sudbury Exiles Rugby Club was a great diversion and we travelled around playing rugby and drinking beer all summer, when not working.
That particular summer, there was a strike at INCO. INCO was famous for fractious labour relations and strikes were often a long drawn out, violent, seething exercise. The day before the strike started, we were called into the chief engineer’s office and told to go back to the bunkhouse, pack enough clothing and personal items for a few days and walk back into the mine that evening. The next day, the strike was on and we were locked in! Only safe way in and out of the mine was by helicopter. A sleeping facility was set up at Coleman Mine, also behind the picket line and a cookhouse was set up at Levack Mine. All of the “management” staff went underground to shut down equipment, ensure pumps were working, be on fire watch, etc. We students worked in the makeshift “cookhouse”, peeling potatoes and carrots, making salads, slinging the food, washing dishes, etc. Whatever “Cookie” and her husband wanted us to do.
During the time, the men outside the picket line threw Molotov cocktails on the lumber yard. A LOT of timber was used underground at that time! Thankfully, the fire was extinguished quickly. The strike got really ugly when one manager’s car windshield was shattered with a baseball bat when he tried to drive it through the picket line. There was a particularly ugly incident where somebody, presumably a union guy, shot at one of the helicopters with a 30-30 rifle! The union men guarded each gateway to the property to ensure none of us management people snuck in or out to visit wives and girlfriends. I recall one union guy, nicknamed “Beancan” due to his habit of eating a can of beans for lunch every day (with the can lid, no spoon) guarded one of the back gates and taped Playboy pin-ups all over the fence and gate!
The strike only lasted 10 days or so. I was in for five days and flown out –my first ever helicopter ride! I learned a lot about management-labour relations during and after that strike. After all of that, all of the union guys got raises immediately after the strike was over AND management did, as well, to match the union wages. All of us students were pretty upset and we gathered en masse at the chief engineer’s office and, essentially were told “Tough!” and dismissed back to our desks.
Anyway, it was a great summer of working, good pay (despite no raise), rugby, beer drinking and freedom from school.
CIL Explosives Ltd in Sudbury. As my last year at the Haileybury School of Mines advanced, I started having job interviews with various mining companies. It was a great time to graduate with multiple jobs opportunities for us all. I enjoyed having job interviews, especially the free lunches and, oft-times, beers that seemed to go with job interviews. I interviewed with INCO and several other mining companies. One opportunity was different. An explosives company, CIL Explosives Inc., wanted some of us to train in explosives technical and sales work. I didn’t want to do that! I wanted to work at a MINE! I decided to go to the interview because some free food and beer could be a partial result. The fellow that interviewed me, Bob Murchie, was an unorthodox interviewer, at least in my very short interviewing experience. I went into the room and here was a guy with his feet up on the table lighting up a cigar! He just talked to me and asked questions that didn’t seem to have anything to do with mining or explosives! In the end he suggested that, if I went to work for CIL, before my career was finished, I would get to visit and work at EVERY mine in Canada. That made me think. Every mine… mineral collecting… Work experience… Mineral Collecting… technical knowledge… Mineral collecting… Sounded pretty good! I thought it was a terrible interview though! A few days later they sent me a telegram saying they would send me a plane ticket to Montreal for a second interview! Montreal! Sure enough the ticket arrived in the mail and I flew to Montreal and had REAL interviews with multiple technical managers, many of whom became great friends in later years.
A few weeks later, a job offer arrived by telegram. I went to the Haileybury railway station to pick it up and was flabbergasted that they offered me a job in Sudbury at the, then, princely sum of $1,200 per month. That was pretty good money for a young fellow in those days. I wrote letters to the mining companies that had offered me jobs, that I could not accept their offers. Upon graduation, I took the bus to Sudbury and was presented with a company car and an expense account. Pinch me! I shared an office with an older Haileybury grad and began my training which seemed to never end. I was always learning.
Sudbury, at that time, was a hotbed of technological innovation, mostly because of INCO and its suppliers. Falconbridge was much more conservative and stodgy. INCO was arrogant but willing to try almost anything to reduce costs, if you could come up with a good idea. I didn’t have any ideas, since I didn’t know much about mining, yet, really. I did work with incredibly innovative scientists and engineers at INCO and CIL and learned a LOT at the “University of INCO”, over two years, that stood me in good stead for the rest of my explosives career. I worked underground at every mine of both INCO and Falconbridge learning the ropes, introducing new explosives and initiation systems and mining methods. It was great!
I helped with the first “virgin” Vertical Crater Retreat mining stope (not a pillar) ever, at Levack West Mine (later called McCreedy West). CIL convinced INCO to try bulk explosives underground so, at Creighton Mine, we loaded a 1.5million ton blast with bulk TNT sensitized, gelled explosives. INCO was one of the first big companies to decide that safety fuse was, in fact, obsolete, both safety and efficiency-wise, so we introduced the brand new NONEL initiation system to all of its mines. We developed new capacitor discharge blasting machines that we sold to many of the mines, or helped them modernize their central blasting systems. INCO decided to totally stop using dynamite and we helped switch them over to EGMN-based water-gelled explosives. We developed shaped charges to make secondary blasting in drawpoints safer and better. It was the perfect time to be an explosives technical service representative in Sudbury.
I am fortunate to have worked on many projects at many of the mines in the Sudbury district including: Levack, Coleman, McCreedy West, Strathcona, Fecunis, Garson, Frood-Stobie, Stobie, Copper Cliff North, Copper Cliff South, Victoria, Crean Hill, Creighton, Whistle and Broken Hammer Mines.
I got married while I was in Sudbury, lived in a couple of apartments and then rented my first house in the “Four Corners” area of Sudbury. It was a happening place at the time with many new, young professionals starting their careers and I made many friends.
I was only based in Sudbury for a couple of years before being moved from coast to coast by CIL. True to their word, I WAS seeing many mines across the country from Vancouver Island to the Island of Newfoundland. I didn’t see them all but most of them!
Eventually, I went to head office and through a series of promotions, ended up being a senior manager in technical, product management and business development roles. For years, I managed the Technical Service Group, a crack group of explosives technical engineers and technologists who could solve any mining, construction, seismic or demolition problem. Many of the technical challenges were in Sudbury and I found myself continuously being drawn back to INCO and Falconbridge operations, at Sudbury, for negotiations, planning, project management and/or technical work. It was still the “University of INCO”!
Eventually, CIL was bought out by our British parent company, ICI, and became ICI Explosives and we acquired the Atlas Powder Company of the USA. That meant I was able to travel the USA and, then, the world acquiring or disseminating technical knowledge and visiting famous mines!
Engineering and Contracting
Eventually, I left ICI Explosives and began a series of positions, mostly in business development for various mining contractors and engineering companies; BLM Group, Dynatec, Aker Kvaerner, Aker-Songer, SNC Lavalin and Aker Solutions. Every one of those positions drew me back to Sudbury. There was no more concentrated center of mining/metallurgical work in North America than the Sudbury area. There were always engineering projects, construction projects, expansions and studies to be done for INCO and Falconbridge and they contracted most of it out.
When I became an adjunct professor teaching “Explosives and Fragmentation in Mining” in the engineering faculty of the University of Toronto, where was the first place that I took my students on a field trip to? Sudbury! The University of INCO. I was able to count on old friends to put on fantastic tours for the engineering students.
I’ve returned to the Sudbury area many times over the years to visit my mineral friends, view their collections, purchase or exchange for mineral specimens, speak at the Sudbury Gem and Mineral Club, etc. I hope this will continue for many years yet!
I was born in Sudbury in 1952 and grew up there. My father worked as a square set stope miner at the #5 shaft of the Falconbridge mine in the town of Falconbridge. In the late 1960’s, a significant production cut was ordered and my father was transferred to the Hardy mine in Onaping. Due to poor road maintenance and conditions at the time, our family moved to the town of Dowling to facilitate traveling to work at the mine.
Dowling wasn’t a very large community and is in the middle of the bush. The best past times I had were fishing, hunting, and generally hiking in the surrounding mountains to pass the time. One day, one of my uncles purchased a car from a man living in River Valley. In the trunk, he discovered two very nice almandine garnets from the River Valley occurrence and gave them to me as a gift. Shortly after this, my father brought home a nice galena cube from the mine to add to my collection. Well now I was hooked! I started collecting micro crystals of galena, sphalerite, calcite, dolomite and pyrite crystals from the Errington and Vermillion mines that were easy enough to get to with my bicycle from my home.
Well it was time to leave home when I turned 18 and as tradition in the Nickel District goes, everyone wished to get hired at the mines with the hope of a long-lasting career. I was hired in 1971 by Falconbridge Ltd. as a labourer at Hardy mine for the summer and in the following 5 years, I held the positions of carpenter helper, crusher man, mechanic, and finally first-class pipefitter helper. I was able to collect some nice minerals from the Hardy mine open pit at this time to add to my collection.
Whenever I was on the Strathcona mine site I would visit the main geology office and sweet talk some of the geologists to donate samples for my collection. Several of the geologists I made friends with encouraged me to think about changing careers and becoming a geologist for the company. On good advice, I left Falconbridge in 1976 to obtain my 3-year Cambrian College diploma of Geology Engineering Technology. In this period of time, I was hired as a field assistant for The Ministry of the Ontario Geological Survey. Working with some of the best geologists in the country allowed me to learn my rocks and minerals very well and foster a deeper understanding of the geology and orebodies of Ontario.
With a diploma in hand, Falconbridge Ltd. hired me in 1979 through 1987 as an underground Beat Geologist and Project Geologist. I was able to work at and collect minerals from Lockerby, Fraser and Lindsley mines. Several layoffs occurred in this period and I quickly organized myself to work private contracts for various companies around the provinces of Ontario and Quebec. I was able to collect many great minerals in the Cobalt silver district and the gold districts in northern Ontario and Quebec.
From 1988 to 2000, Falconbridge hired me again as a Project Geologist. My duties were to discover or delineate orebodies in the Sudbury Igneous Complex. In this period of my career, I obtained my B.Sc. in Geology from Laurentian University in Sudbury in 1990. As a Project Geologist, I was able to work at all the mines in the district and could once again collect minerals from surface dumps and underground at the active mines.
The following exploration projects are some of the larger underground and surface exploration programs I completed personally or with the exploration team in the Sudbury Igneous Complex: Falconbridge, Trillabel, Lockerby East, Denison, Kildream, Creighton, North Star, Lindsley, Manchester Offset, Norduna, Nickel Rim Depth, Nickel Rim, Parkin Offset, Fraser Mine 5W zone, Thayer Lindsley, Craig-Onaping Depth.
Another downturn occurred and I was de-hired by Falconbridge Ltd. In 2000. I updated my consulting business and got busy completing geology exploration contracts for Sudbury District mining companies such as Wallbridge Mining Co. Ltd. and FNX Mining Company, Ltd. to name a few. FNX Mining Company Ltd. hired me in 2003 as an Exploration Geologist to work on their core properties; Falconbridge, McCreedy West, Levack, Kirkwood and Victoria.
FNX was quickly purchased by Quadra FNX and KGHM Polska. Under KGHM my duties included completing all the company mineralogy and petrography projects for the Sudbury area and all the company’s exploration projects around the world. This gave me the opportunity to collect minerals from localities in Chile and Africa.
KGHM de-hired me in 2014 and I am presently retired as a professional geologist. I operate Roger’s Minerals and supply rare minerals to collectors and researchers.
At the present time, my home is filled with mineral specimens from around the world. It all started with those two garnets and has ended in 5,524 specimens collected over a span of 60 years.
Writing this article has made me remember all the friends I made along the way.
Just so that you can visualize them, Here are a few more random photos of mines and scenes from around Sudbury.
In 1969, I was fourteen years old. I was a very keen mineral collector and my brother Brian and I were members of the “Rockids”, the junior arm of the Scarborough Gem and Mineral Club, Scarborough, Ontario, Canada. At that time, there was a dedicated group of adults who organized a meeting for us kids one Saturday afternoon, every month, plus great field trips. The meetings had all kinds of activities, including mineral identification, monthly guest speakers, mineral properties demonstrations, borax bead tests, blowpipe tests, microscopes, LOTS of free mineral samples, displays and activities to take home to work on. I thought the meetings were heaven! I looked forward to them every month.
One of the key features of the club was that, whether they knew it or not, each kid was competing to amass points. Whenever you excelled at an exercise, did well in the What’s’it, the mineral identification contest held every meeting, or even just attended, you received points. The two kids that amassed the most points at the end of each year got to go on a trip to visit a mining operation somewhere in Canada’s north. In 1969, I was one of the two young people selected to visit Steep Rock Iron Mines, at Atikokan, Ontario, all expenses paid by the company.
This was a serious trip! We flew from Toronto to Port Arthur (it has since been re-named Thunder Bay), and then flew in a bush plane, a De Havilland “Beaver”, to Atikokan. You could drive to Atikokan but I think the company figured it would be more of an adventure if we were flown into Atikokan in the small plane. It was! I’d been in a big airplane before but nothing like the Beaver! I was a southern Ontario city boy and I couldn’t believe the extent of the forest, the rivers and the lakes that we flew over between Port Arthur and Atikokan. Of course the pilot buzzed the giant open pit mines and the town before we landed, for the most dramatic impact.
Steep Rock Iron Mines gave us rooms in the Directors Lodge, a big, well appointed, home in Atikokan. I was struck by the red colour of the cars, roads, our shoes and my hands every time I touched something. Fine-grained hematite was EVERYWHERE! A real iron town.
One of the geologists, at the time, was a fellow by the name of Dave Mulder. He was one of our key contacts during the visit. Another was a foreman, Stan ……. something. I’m afraid that I cannot remember Stan’s last name. Dave and Stan took us through the operation from offices, to underground mine, to open pit mines and the mineral processing facilities. They were both great to a couple of 14 year olds.
We looked at all kinds of things. However, all that I really wanted to do, though, was collect minerals! We had a couple of good chances. I recall that Dave Mulder was incredulous that we would want to stop all the time and bash rocks and wrap specimens. “What are you going to do with them?!” And specimens there were! When we visited the ore body at the bottom of what I think was the Hogarth Pit, there was botryoidal hematite everywhere. I picked up some nice pieces. I could have had a lot more but I was shy. Wish I was could re-live that moment! As well, we were turned loose on the waste dumps which seemed, at that time, to be littered with chunks of breccia that were loaded with quartz crystals, calcite and iron carbonate. I bashed, pried and took as much as I could.
We were treated like princes –well fed and watered. I recall sitting with the mine managers one evening, listening to them talk, as they sipped some sort of adult beverages and smoked cigars. I didn’t understand much! At one point I heard one of the men talking about American investing in Canada. Now, I was just a 14 year old, naïve and impressionable. Some may recall that, at that time, Pierre Trudeau had instilled a nationalistic streak in many Canadians and foreign ownership was viewed with suspicion. The Canadian government had even nationalized a number of large “strategic” companies. I chirped in, to the mine managers’ conversation, that “American investment in Canada and control of our companies was a real problem”. Well, did I get an earful! I got a fast lecture on how it was American investors that had put up the money to develop Steep Rock Iron Mines and how American investors were our friends not enemies. I’ve, since, learned a lot about how the capital markets and corporations work but that early lesson still rings in my ears!
We drove back to Port Arthur from Atikokan, a several hour drive. Another learning experience. Along the way we arrived at an accident scene just minutes after a car of native men went off the road and bashed into a road cut. Most of them were dead amongst the rocks and it was the first time I’d seen people dead from such a violent end. The one fellow that was still alive, the driver, was bleeding profusely from his head so we put him in our car and I sat next to him as we sped towards the Arthur hospital. We wrapped his head in spare shirts to stem the blood flow. Along the way we picked up a police escort and sped through all of the lights, dropped him off and then headed for the airport. I don’t recall anything else but I expect our chaperone had to make some kind of statement to the police, since alcohol was involved.
I had loaded up my suitcase with my belongings and LOTS of mineral and ore specimens. For some reason, I was allowed to carry it onto the plane although it was a rather large and heavy suitcase. The stewardesses made me put it at the back of the plane and were amazed at the weight of it. They asked me WHAT was in it and I just replied “Rocks”. They didn’t seem to believe me.
Back home, I was the envy of all of the other kids - SO many nice mineral specimens that I collected. Not many of the specimens have survived. After going to college, moving across Canada, back and forth, probably 15 or sixteen moves, since then, many of the specimens got damaged. As well, when I returned to Ontario, from that trip, I went to the Bancroft Gemboree and traded many of the specimens away. Wish I’d kept them!
We had a ball and I think it was that trip that ultimately led me to a career in mining. Mind you, I decided to go the mining explosives/ engineering/management route rather than the geology route that I had originally envisaged.
Some information about Steep Rock Iron Mines
The mine at Steep Rock Lake was spawned from the dire need for iron ore by the United States during the later stages of World War II. Apparently, German U-boats were sinking a huge percentage of ore carriers from Latin America and the USA wanted to secure more supplies, besides its own mines.
The ores occur in a series of metamorphosed volcanic and sediments that has been tilted almost vertically. There was significant faulting in the area. This deposit is similar and related to the great iron deposits of Minnesota and Wisconsin.
It had been theorized, since the late 1800’s that there was a lot of iron mineralization under Steep Rock Lake.Trouble was, it was only a theory, since only chunks of hematite had been found around the large Steep Rock Lake. Finally, in 1938, many diamond drill holes were drilled to delineate a very large body of iron mineralization. Direct shipping iron ore. It was decided in the succeeding years to drain the lake, divert the river that fed it, dredge the silts and gravels in and around the lake and then mine the iron ore. Steep Rock Iron Mines was formed in 1938 and was listed on the Toronto Stock Exchange later that year. Plans were made to commence the design and building of a mine and ore handling facilities. The war effort and the shortage of iron ore accelerated the entire effort, greatly.
In 1942, Cyrus S. Eaton, an American financier, became involved and steered the efforts to bring the funding to Steep Rock Iron Mines, enabling it to go to production. Two years later, the first ore was shipped to Superior, Wisconsin by rail. In 1945, ore handling and ship-loading facilities were completed at Port Arthur for more flexible shipping to ports on the St. Lawrence Seaway.
The engineering and construction efforts to uncover the deposits and bring them to production were formidable. Lakes had to be drained, rivers diverted and huge amounts of silt and gravel moved. A few facts:
I’m sure that a tremendous amount of environmental damage was done during the rapid development of this operation. I expect that it was partially due to the times and the haste in which it was built. I suspect that it would be have to be done very differently, these days.
Interestingly, another deposit, the Bending Lake Deposit, was supposed to be the next deposit mined by Steep Rock Iron Mines. It turned out to not be feasible, at the time. Still there and others are looking at it.
In 1949, Caland Ore Company was formed by Inland Steel to mine the Caland Property, close by, under lease from Steep Rock Iron Mines. That is where most of the nice manganite crystal specimens came from! It took until 1960 for mining to commence. There was much financing, engineering, permitting and construction to accomplish first!
Summary
I wish Steep Rock Iron Mines was still going. Not only was it a cornerstone of the economy of NW Ontario, it was a source of great mineral specimens. Because of its remoteness, relatively few mineral specimens were recovered. It had the potential to become a “Cave-in-Rock”, “Arkansas” or “Jeffrey Mine” for beautifully crystallized minerals.
Besides my own first-hand knowledge of Steep Rock the following references were helpful.
http://twosox.htmlplanet.com/steeprock/steeprockpage.html lots of good history, photos, etc.
Sona, V.A., Steep Rock Iron Mines, Dredging and Draining of Steep Rock Lake and some of the effects after 45 years. Proceedings of Tailings and Mine Waste ’02, Swets abnd Zeitlinger, ISBN 90 5809 353 0
http://econgeol.geoscienceworld.org/cgi/content/abstract/50/4/373 this has a nice summary of the geology.
If you “Google” Steep Rock Iron Mines, you’ll find lots more information.
Some Additional Images
All specimens are from D.K. Joyce collection, unless noted.
General
For an extended period of time, each year, during winter in Canada, huge deposits of a common mineral, ice, inundate us. The focus of this article is the ice mineralization that encrusts most open bodies of water in this part of the world and its effect on sport fishing activities.
Chemistry
When conditions of pressure and temperature are in a range defined as less than zero degrees Centigrade and pressures of less than 101.325 kPa, significant amounts of the common mineral ice form from the aqueous solutions in the air and on the surfaces of lakes, ponds and rivers. These mineralized deposits are largely H2O with trace amounts of many elements, particularly calcium and sodium. As well, ice crystal deposits often contain inclusions of many organic and inorganic compounds.
Pure ice has a hardness of 1.5 on the Moh’s scale and a density of 0.9167 g/cc. Colour varies from white, colourless, black, blue and green, with many variations, depending on the colour of the underlying water, as well as inclusion colour and density.
Effect on Fishing
During much of the year, access to the surface area of lakes, by foot, is limited to a few metres from shore or as far as a good arm can cast bait with a fishing rod. The only alternative to access further out into the lake is to use boats or canoes, often an expensive, dangerous and cumbersome activity. The advent of ice crusts on lake surfaces, facilitates access to the entire surface area of most lakes by foot. This is a real boon to sport and subsistence fishing (by foot or land-based vehicles), during winter. Of course, it makes access by boat or canoe impossible!
Ice crystals begin forming when water temperature is edged to lower than zero degrees Centigrade by much colder air temperatures and lack of radiant solar energy due to very short periods of daylight. Within a short period of time, the ice crystals merge to form a thin crust which thickens in a relationship directly proportional to air and water temperature. When ice thickness reaches 100mm or more, it, generally, will safely support most human weight. Sub-ice water currents could affect thickness and stability of the ice and are often unpredictable. With appropriate continued air temperatures, ice mineralization will continue to thicken to the point that it will support all-terrain vehicles and even trucks and air-planes on skis. Generally, ice thickness of 0.3 metre are recommended before driving trucks on the ice. Many anglers pull small wooden “huts” or “shacks” onto the ice and leave them there for the duration of the season when ice mineralization is possible.
Ice is a dynamic structure, and behaves much like a horizontal rock structure. Pressures caused by expansion and contraction under temperature and water level fluctuations can cause rifts, cracks and faults (vertical and transverse displacement), all of which can result in dangerous conditions. Often cracking takes place while fishing causing feelings of apprehension amongst novices due to the rather large sound and movements that occur, close by. Generally, cracking of a 0.3m ice layer, although un-nerving is not dangerous. On occasion, non-thinking anglers venture out on areas of ice open on three sides. A large crack on the fourth side can release a large sheet of ice, with the anglers on it, out into the main body of water.
Ice Penetration Techniques
The traditional technique for penetrating the ice mineralization, to access the underlying water (and fish), is to chop a hole through the ice with an axe. Manual augers are commonly used to bore holes of 100-250mm diameter. The author has augured holes, manually, through 1.5 metre in northern Ontario! On occasion, chain saws are used to cut larger holes. Today, serious anglers have gas engine powered augers to facilitate penetration of the ice. These augers make hole production quick and easy.
Fishing Techniques
Methods of fishing through ice mineralization are varied, depending on the region and the species of fish sought. Generally a baited hook is lowered through a hole in ice by short rods, various spools, sticks, etc. The angler simply waits for the fish to attack the bait, sets the hook and then pulls the fish through the ice mineralization via the hole. Easy! Much easier than when there is no ice mineralization to stand on!
Of course, these days, many fisherman use sonar- based electronic instruments to locate fish and increase their chances of catching them.
Summary
The formation of ice mineralization on Canadian lakes results in conditions that enable anglers to travel by foot or wheeled vehicle on the, otherwise, un-accessible surface of those bodies of water. During periods when winter temperatures do not reach adequate sub-zero levels, the ability of anglers to access lake surfaces is limited.
Acknowledgements
I would like to thank my son-in-law Brad Jamieson for the use of his equipment and his guidance in recent ice fishing expeditions. As well, my brother Brian and sister-in-law Mary Joyce who provide tremendous hospitality!
Introduction
I’m new to Arizona. I’ve grown up in and lived most of my life in Canada. That means the desert landscapes, flora, fauna and types of minerals (secondary minerals) of the South-West are all new to me! I’ve travelled much of the world but Arizona is one of THE most interesting, intriguing and satisfying environments that I have encountered (especially during winter and spring!).
Recently, I joined a field trip of the Tucson Gem and Mineral Society, destination; the Red Cloud Mine, north and east of Yuma, not far from the California and Arizona border. I left Tucson and travelled NW on I-10 to Highway 8 and then west on Highway 8 to Yuma for a stay overnight and ready to start early the next morning, heading up highway 95 towards the mine.
I had NO idea what collecting would be like. Actually, I didn’t care. It just seemed like a good idea to visit the Red Cloud Mine which is one of the premier mineral localities of the world. This year, 2019, was the year of the “Wulfenite is Loved” theme at the Tucson Gem and Mineral Show and visions of colourful, well-formed crystals of the AZ-ikonish, lead-molybdate were floating around in my brain. The trip to the mine was important and, if I happened to find some good crystals, that would be a bonus!
I think that I enjoyed the drive from Tucson to Yuma and then to the Red Cloud Mine just about as much as I enjoyed being AT the Red Cloud Mine! This “article” is really a photo-essay showing the road trip to the Red Cloud Mine, a little about the location, collecting and then some of the minerals that I returned with. I’ll show you some of the scenery, flora and minerals that I encountered. Didn’t encounter any fauna! I hope you enjoy it, as well!
About the Red Cloud Mine
The following information has been summarized from Arizona Lead and Zinc Deposits, Part II, Arizona Bureau of Mines, Geological Series No. 19, Bulletin # 158, kindly provided to me by Les Presmyk, an authority on the Red Cloud Mine and "all things Arizona", when it comes to mineral specimens. I’ve added my observations to the information gleaned from the reference.
The Red Cloud Mine was a fairly small mine, as modern mines go. It is located at 750 feet above sea level, near Yuma and the California border with Arizona. It was originally mined during the 1880s and over the years, developed to a depth of 500 feet or so via various shafts, winzes, raises, drifts and stopes. The remnant vein mineralization in the 1950s averaged about 6% lead and 10 troy ounces or so of silver per ton. There were no doubt higher grade sections of the veins, earlier, but few records are available.
The vein occurs in a fault zone and is composed mainly of “limonite”, hematite, quartz, fluorite and calcite. According to the Arizona Bureau of Mines (ABOM) report, there is considerable fault gouge and brecciated rock around the vein. I observed this in the surface exposure of the vein and expect that the underground workings were tricky due to difficult ground conditions. There are many open spaces in the vein material and the openings are often drusy quartz lined. When not filled with iron and manganese oxides the openings commonly contain fillings or crystals of wulfenite, willemite, cerussite, mimetite and calcite. According to the ABOM report, there also can be malachite, vanadinite, smithsonite. Small masses of galena can be found and, presumably in large masses, at times since argentiferous galena was the main ore mineral. Also according to the ABOM report, the galena can be associated with anglesite, cerussite and cerargyrite. As well, the report indicates that the lower workings contained more zinc mineralization than lead, all in secondary minerals. Odd, though. I didn’t see a trace of zinc mineralization during my limited visit.
I was surprised at the number of open spaces in the vein material and the quantity of small crystals of wulfenite, willemite, cerussite, mimetite and hemimorphite. I recognize that I was looking through vein material both in-situ and loose that is the “leavings” of several waves of professional collectors. Still, there are beautiful, small but macro wulfenite crystals to be found and oodles of micro crystals. Roger the resident collector, mentioned further, below, has found some beautiful large and significant crystals and specimens of wulfenite. He spends many hours exploring the workings and has learned where to look. He was very generous with his knowledge and guidance but we were probably not shown the best place to collect on surface and certainly we did not go underground. (I would have loved to!)
Results of Collecting
I was fortunate to find a number of wulfenite crystals, all small but, still, beautiful and classic Red Cloud Mine. They all have that red-orange colouration, sometimes more red and sometimes more orangey. As well, I also found lots of really nice willemite, all sharp micro crystals and all brilliantly fluorescent.
As well, I did find cavities of fluorite crystals. The fluorite crystals are not great crystals and mostly colourless but often serve as substrate for the more exotic minerals. The fluorite has nicely blue-purple fluorescence and adds to the intrigue of the rich willemite specimens. Similarly, there are lots of vugs lined with drusy quartz crystals that sparkle in the strong, ever-present Arizona sun. The quartz druses are often the base for the more rare minerals.
Additionally. I did find a couple of vugs with hemimorphite, mimetite and cerussite crystals. I expect that, if I spent more time at the mine and with the microscope, I’d find other well-formed crystals of various minerals.
Here are some photos of the minerals that I found:
ALL of the Willemite fluoresces a bright green colour like in Figure 46. For some reason, I could not capture that colour through the microscope. All of the micro Willemite photos show the mineral with a ghostly whitish glow.
Other Specimens
Here are some REAL wulfenite crystals and specimens:
Summary
I was delighted to visit the Red Cloud Mine after knowing about it all of my life and after having sold a number of nice specimens over the years. Hopefully, I’ll return there sometime in the future and undertake another attempt to find a larger cavity with some larger, beautiful crystals in it than I found the first time! In the meantime, I hope that you enjoyed the trip to the Red Cloud Mine as much as I did.
Acknowledgements
Thanks to Roger, at the Red Cloud Mine, for his guidance during the visit. I hope that he continues to find great crystals.
Thank you to Les Presmyk for the knowledge that he shared about the mine.
And thank you to Ray McDougall for the use of his photographs.
In 2013, my collecting partner, Ray McDougall, and I had a unique opportunity visit and collect at the Quiruvilca Mine in Peru. Ray is a securities lawyer, on Bay Street, Toronto, and had acted for Southern Peak Mining when they acquired the mine from Pan American Silver in 2012. He had exacted a promise from the president of Southern Peak Mining that he (and I) would be granted an opportunity to visit the mine and collect minerals, sometime shortly after the deal was consummated. Ray contacted Southern Peak about fulfilling the promise, in late 2012, and we made our arrangements to travel to Peru in March 2013. It would be an honour to visit such a famous, classic mineral locality and collect on-site!
The Trip
The first part of the trip was like international travel anywhere; airports, line-ups, security, long overnight flight, busy airports, etc. After landing in Lima we stayed in the airport and caught a flight to Trujillo, the closest city to Quiruvilca. Southern Peaks sent a driver in a spacious SUV to pick us up for the drive to Quiruvilca. Originally, we had planned to stay over in Trujillo and drive to Quiruvilca the next day. We were informed that the new road to Quiruvilca was in very bad shape due to the construction and the very heavy rains that they had been experiencing recently, so much so, that we needed to head up to Quiruvilca the day that we arrived. So we did! The first leg of the road trip to Quiruvilca was pleasant enough on paved road, by the sea shore, through many, many fields of sugar cane. Eventually, we turned up a valley and started to climb into the precipitous mountains that are never far from the narrow coastal plains. The road is only in good shape until Carabamba. After that point it is under construction and is, for several hours, a long, curving, bone jarring, muddy, pothole filled construction site that never seemed to end. The area above and east of Trujillo is a booming mining area with several large mines under development and the old road is a key conduit into the region for supplies, fuel, raw materials, fuel, explosives, equipment and people. As a result, the very heavy traffic on this, currently, pitiful road, through muddy or dusty (depending on the weather) towns, was a constant stream of supply vehicles; buses, cars, pick-ups and tractor trailers. When it is completed, it will be a blessing!
The recent weather did not help road conditions. Above average heavy rains had served to make maintenance impossible, create amazing amounts of mud, induce rock-slides, and cause the heavy traffic to create huge potholes. As a result, progress up the grade to Quiruvilca was slow and dirty, for the most part.
Quiruvilca Mine
Mineralization was first reported at Quiruvulca in 1789. Mining at a corporate level started in 1907 and more or less until 1930 or so. The Quiruvilca Mine has been in continuous operation since about 1940. The nature and grades of the deposit have caused it to alter the types of metals that it has produced over the years from originally copper/silver to copper/gold to the current lead/zinc/silver. The deposit(s) are zoned and the plan view in figure 8 shows the four metallographic zones. The workings are extensive, spread out over a wide area, in many veins. Currently, grades run at about 150 g/t silver, 4% zinc, 1.5% lead and 0.5% copper. Stoping is taking place in, reportedly, 60 places. Considering the 1725 tons/per/day that the mine can process, that is a lot of small stopes! The underground working places are accessed by several adits/ramps and one shaft. Ore is moved to surface, primarily, by one long conveyor belt system but also supplemented by rail movement from ore passes plus skip-hoisted ore. When we looked at a plan of the workings and saw the many, many kilometres of drifts and ramps, we understood why we had to walk so far between stopes!
In essence, the mine is a hodge-podge of several past mining initiatives, haulage methods and development approaches, as is often the case with older mines.
The mining method in the stopes that we observed was remarkably consistent and seemed to consist of a modified narrow-vein, undercut method of mining, necessary due to the incompetent nature of the vein material. Essentially, a raise is driven near-vertically, and compartmentalized to serve as a manway as well as a mill-hole. Ore is blasted and then moved with scrapers and cables from the face to the mill-hole. Rail cars are then loaded from a chute at the bottom of the mill-hole. The stopes are heavily timbered due to poor ground conditions. I didn’t notice any back-filling of completed stopes. In some places, the ore minerals seemed to be high-grade sulphides held together by clay which seemed to have no tensile strength whatsoever.
All to say, I expect that mining costs are probably fairly high but overall costs offset to a payable level by the good grades and low labour costs.
Geology
The geology of the Quiruvilca Mine is fairly simple but interesting. I will “lift” a geological description directly from the book, “Peru, Paradise of Minerals” by Guido Del Castillo, Edited by Art Soregaroli. Those authors relied on geological descriptions by Bartos (1983, 1987, 1990) and Lewis (1956).
The Quiruvilca deposits are in layered volcanic rocks of the Miocene Calipuy Formation which includes andesite and minor basalt flows. The Calipuy formations has an estimated thickness in excess of 2,000m. Intrusive rocks include andesite stocks and dykes.
The ore zones have four distinct zones. Ores in the central part of the district are mesothermal and are dominated by enargite. The mesothermal deposits grade outward to the epithermal deposits. Lewis (1956) described the various zones in some detail.
The inner zone is called the Enargite Zone and, in the past, encompassed the major part of the Quiruvilca Mine. Little mining is done in that zone today. Minerals associated with the enargite in this zone are pyrite tennantite, wurtzite, sphalerite, chalcopyrite, orpiment, galena and rare hutcinsonite.
The second zone outwards is the Transition Zone which is up to 1,400m wide. Its dominant ore mineral is sphalerite with pyrite and tennatite-tetrahedrite. Other sulphides include chalcopyrite, galena, marcasite, arsenopyrite, covellite and wurtzite. Gangue minerals are mostly massive quartz and occasional rhodochrosite and calcite.
The third zone outward is the epithermal Lead-Zinc Zone characterized by sphalerite and galena accompanied by pyrite, chalcopyrite, tetrahedrite-tennantite, marcasite, arsenopyrite and gratonite. Gangue minerals in the lead zinc zone are quartz, dolomite, rhodochrosite and calcite.
The outermost zone is the Stibnite zone. In addition to stibnite, the other minerals there are arsenopyrite, pyrite, sphalerite, galena, chalcopyrite and arsenic.
During our visit, we spent most of our time in the Lead-Zinc and Transition zones.
The Town
Quiruvilca seems to be totally dedicated to the Quiruvilca mine. Some of the mine workings are accessed within town limits and easy walking distance of the town. You can often see miners and workers walking to and from their homes in their working gear. Homes seem to be very modest and crammed into every available space. The Mineralogical Record article by Crowley, Currier and Szenics shows a photograph of the town in 1976 or so and it seemed to be much less concentrated than it is now.
We were very fortunate that Southern Peaks resources invited us to stay in the “Mine Managers house” within the gated/guarded company compound near the mine offices. The compound is a beautiful enclave with nice management homes and bunkhouses, gardens, trees, etc. Our driver would pull up to the gate and a uniformed guard would rush over to open the gate and salute as we passed into the compound. This was repeated on the way out.
The mine manager’s house is like a guest house with seven or eight bedrooms, a couple of bathrooms, washing facilities, dining room and a very nice living room. Marina, a very nice lady, who has worked in the Mine Manager’s house for 30 years making guests comfortable, preparing meals, cleaning and making it a “home away from home”. She was very helpful and hospitable to us, always greeting us with a smile and a welcome. Each morning we would go underground collecting and then come back to the house to get cleaned up and have a late lunch. Afternoons were spent cleaning the minerals and, mostly, reading and chatting by the fire or visiting mine staff to learn about the area.
The mine facilities, including the mine manager’s house were “dry”. All that good food and accommodations were begging to be accompanied by a nice before dinner aperitif or some fine wine during supper but it was not to be.
Very few people spoke English at Quiruvilca (we only met two, the doctor and one manager) so we worked hard, the entire time, with our limited Spanish, to understand, to be understood and make conversation. People were very accommodating and went well out of their way to help us.
Quiruvilca is situated at about 3800 metres (12,500 feet) elevation so the effects of altitude are always apparent. I’ve been “at altitude” many times and always feel light-headed, perhaps with a slight headache and get winded very quickly when climbing or exerting myself. Unfortunately, Ray had a stronger reaction, after a day or so, with racing pulse, nausea, bad headache, etc., so much so that he spent a better part of a day, recuperating and dosing himself with oxygen, under the supervision of the company doctor.
Collecting
Ray and I were allowed to go underground to collect on three days. Geological and production staff were very amenable to accompanying us and leading us through the extensive workings to working stopes. Most of the workings, currently, are in the Zn-Pb-Ag zone, so exotic minerals such as orpiment, enargite, arsenic, etc., were not seen. On the first day, we did encounter a zone of very dark sphalerite crystals associated with some spherical pseudomorphs of galena after, possibly, enargite. Fun to collect.
On the second day, I had a particular thrill. We visited a stope in the Pb-Zn-Ag Zone and encountered a vug containing interesting iridescent, gemmy sphalerite. It was extra fun that the miners and geologists all stopped work to watch me clean out the vug and wrap the specimens. The specimens were not “world beaters” but, as it turns out, each one had with tiny, beautiful, sharp seligmannite crystals associated with the sphalerite. These are significantly different from the seligmannite crystals from La Paloma Mine.
On the third day, we found some sort of botryoidal sphalerite speckled with tiny crystals of tetrahedrite. There were open spaces/cavities in all of the stopes that we visited but most were too small to produce any good specimens. It the old adage that “you have to be in the right place, at the right time” in order to be able to recover good specimens.
The thing is, there is little mining, currently, in the Cu-Ag zone, also known as the “enargite zone” which was the zone that produced the really good enargite crystals, orpiment and hutchinsonite, in the past. The veins that were of the best grades were simply worked out years ago. It seems that the company is going to develop some new workings in the enargite zone which could be good news for mineral specimens. That said, there ARE good specimens being produced at Quiruvilca but in smaller quantities than in the past.
Lima
Lima is a huge, sprawling metropolis with many neighbourhoods. For some reason, the sky is often obscured by a haze that comes in off of the Pacific Ocean so, although it is often sunny, it doesn’t always SEEM sunny. We were fortunate to stay in Miraflores, a relatively well-run, safe, attractive area of the city, right beside the ocean. As a result, we were able to stay in a nice hotel, take pleasant walks along the cliffs in the evening to watch the sun set, eat our meals at sea-side restaurants, etc.
Very civilized! The mineral dealers , in Lima, seem to congregate in an area west of the Plaza San Martin, which just happens to be in one of the more difficult and dangerous areas of Lima. I managed to have my small camera stolen from me, while walking between dealers, by a “pick-pocket” during our two forays there. I wouldn’t have minded so much if the thief had been a little more considerate and left me the memory card with the contained photos! I wonder what she thought when she looked over the images?
Some Minerals
Here are some images of specimens that we collected at Quiruvilca mine or purchased locally or in Lima. Further down are some other specimens of nice minerals from other localities in Peru. They are from Quiruvilca Mine, unless noted otherwise.
More Pictures!
References
CROWLEY, J.A, CURRIER, R.H. and SZENICS, T. (1997) Mines and Minerals of Peru, Mineralogical Record, Vol.28, 21-28
SOREGAROLI, A., DEL CASTILLO, G. (2010), Peru, Paradise of Minerals, Museo Andreas Del Castillo, 55-72
Southern Peaks Mining Website : www.southernpeaksmining.com
I have visited the Bay of Fundy area many times in the past few years, mostly together with my friend and collecting partner Raymond McDougall. We’ve taken lots of pictures, had many adventures, met great people and brought back many specimens for our mineral businesses. My plan was to create an article for my website, like I usually do, to inform people about this interesting area of the world. Ray beat me to it and did SUCH a good job that I can’t see creating my own article. Instead I am providing you a link to his article on his website!
Read Ray McDougall's Article "Nova Scotia Mineral Collecting - The Bay of Fundy" Here
Have a good read! For other reading on collecting minerals in Nova Scotia, have a look at these articles on my website:
I have many interesting and attractive mineral specimens on my website from the Bay of Fundy region. You can look at specimens in the main “Minerals” listing on my site under these headings by clicking on these links:
Or just go to the main “minerals” section of my website and scroll down to “Zeolites, Nova Scotia”!
This listing of mines of the Cobalt-Gowganda area is a distillation of the mines listed in “Silver Cobalt Calcite Veins of Ontario, Ontario Department of Mines, by A.O. Sergiades, 1968. Changes that are known have been added, along with notes of particular interest to mineral collectors. The Lat/Long coordinates have been cross–referenced with current coordinates in the Government database in a best effort to be accurate. If you’d like to get a better visual idea of where many of these mines were, please visit the “Antique Map of the Cobalt Mining Camp” map located in the “Articles” section of this website.
I think that there are certainly errors in this material but, for the most part, there is good information on all of the bigger specimen producers and obscure mines.
Please note that most of these old mines are on private property and that permission needs to be obtained to visit any of them.
Cobalt Area
| Coleman Township | Tr. Oz Ag | Co -lbs |
| Alexandra Silver Mining Company Lat. 47º 22’ 28” Long. 79º 40’ 32” | 3,612,195 | 116,845 |
The Alexandra Silver mine was started in 1906 and became the Canadian Gold and Silver Mining Company in 1913. After two years of operation it was leased to various individuals, until 1962 when Silverfields Mining Corporation began to work it.
During the 1970s and 1980s, Teck Corporation purchased the Alexandra Property and operated it as the Silverfields mine. Teck mined and milled ore from other claims in the Cobalt Camp and operated them all as the Silverfields mine. The main Silverfields mine shaft and mill were near Cart Lake and served as a main source of mill feed. The Silverfields mill, however, also processed ore from dumps, small underground operations, pillar mining operations and as a custom milling operation, until 1983.
| Beaver Consolidated Mines Limited Lat. 47º 21’ 44” Long. 79º 38’ 26” | 7,127,858 | 139,868 |
The Beaver has long been a source of excellent high grade silver/cobalt specimens as well as leaf silver. In the late 1990s, cobalt ore was recovered from both the old Beaver and Timiskaming mines simultaneously from a shaft on the Beaver mine property and so newer dumps on the property are composed of a mix of material from both claims. Collectors may, thus, encounter specimens from the Beaver-Timiskaming mine.
| Brady Lake Property Lat. 47º 21’ 32” Long. 79º 38’ 54” | 2,250,136 | 190,812 |
Actually composed of three original claims; Lumsden, Rochester and Pan Silver. They were operated and separate properties until amalgamated under “Brady Lake Property” in 1947.
| Buffalo Mines Limited Lat. 47º 23’ 36” Long. 79º 41’ 28” | 14,154,558 | 152,406 |
Operated by a number of mining companies and leases, over the years before being acquired by Agnico Mines in 1957.
| Chambers Ferland Mining Company Limited Claim RL401, PCL 3&4 Lat. 47º 24’ 13” Long. 79º 40’ 41” | 2,297,000 | 25,415 |
| Claim RL402W, RL400E ½ Lat. 47º 23’ 53” Long. 79º 40’ 36” | 2,000,000 | 2,057,142 |
These claims were owned or leased by many companies but half of the production was accomplished by Silver Miller Mines Limited between 1954 and 1958.
| Christopher Silver Mines Limited Lat. 47º 21’ 22” Long 79º 38’ 55” | 4,100,000 | 2,143 |
Also known as Columbus Cobalt Silver Company, Cobalt Consolidated and was finally acquired by Agnico Mines Limited.
| City of Cobalt Mining Company Limited Lat. 47º 23’ 35” Long. 79º 41’ 25” | 14,000,000 | 25,022 |
This mine operated right under much of the central part of the town of Cobalt. The old head frame is still standing and currently houses a café. Also operated by Mining Corporation, Cobalt Properties Limited and eventually Agnico Mines Limited.
| Cobalt Badger Mining Limited Lat. 47º 21’ 52” Long. 79º 38’ 58” | 3,475 | 112 |
| Cobalt Lake Mining Company Limited Lat. 47º 23’ 29” Long. 79º 41’ 09” | 6,900,486 | 146,204 |
This property was made up of all of the land underneath Cobalt Lake and was operated by a number of companies over the years.
| Cobalt Lode Silver Mines Lat. 47º 21’ 24” Long. 79º 38’ 39” | 4,493,725 | 2,547,404 |
| Cobalt Silver Queen Limited Lat. 47º 23’ 19” Long. 79º 41’ 52” | 1,406,214 | 168,462 |
| Cobalt Townsite Mining Limited Lat. 47º 23’ 29” Long. 79º 41’ 27” | 32,150,746 | 4,120 |
| Cochrane Cobalt Mining Limited Lat. 47º 21’ 27” Long. 79º 38’ 24” | 33,280 | 2,705 |
| Colonial Mining Company Limited Lat. 47º 23’ 43” Long. 79º 39’ 41” | 1,211,956 | 3,675 |
| Coniagas Mines Limited Lat. 47º 23’ 51” Long. 79º 41’ 22” | 33,963,067 | 310,557 |
When I (DKJ) attended the Haileybury School of Mines, I visited the underground workings of the Coniagas (Cobalt-Nickel-Silver-Arsenic) mine a couple of times to learn how to do geological mapping underground. I recall that the mine manager showed us big chunks of high-grade silver consisting of masses of black, heavy silver arsenide and sulfide mineralization that they were recovering from “pillar-robbing” extraction work.
This claim was operated by W. Trethewey for two years before it was acquired by Coniagas Mines Limited It was bought and sold by a number of companies over the years.
| Conisil Mines Limited Lat. 47º 22’ 12” Long. 79º 39’ 40” | 100,000 | |
| Consolidated Silver Banner Property Lat. 47º 23’ 19” Long. 79º 41’ 52” | 41,701 | |
| Cross Lake O’Brien Property Lat. 47º 23’ 29” Long. 79º 38’ 44” | 2,846,103 | 97,211 |
This property was operated for many years by M.J. O’Brien Limited and then by Deer Horn Mines Limited Specimens may also be referred to as coming from the Deer Horn mine.
| Crown Reserve Mining Limited Lat. 47º 22’ 33” Long. 79º 39’ 33” | 20,325,302 | 33,713 |
This claim consisted of all of the land under Kerr Lake. Spectacular silver specimens have been recovered by mineral collectors in the area of the mine workings.
| Drummond Mines Limited Lat. 47º 22’ 36” Long. 79º 39’ 11” | 3,887,585 | 246,029 |
The Drummond mine was owned by Henry Drummond, a famous Canadian poet. He immigrated from Ireland, attended McGill University and became a medical doctor. He became famous writing poems about the French Canadian Habitant, the rural people of Quebec. He learned about the silver strikes at Long Lake from an assayer at McGill University and headed to Cobalt. He staked a claim just north of Kerr Lake, and operated and managed the Drummond mine until his death in April of 1907. The Drummond Cairn was originally the chimney from his home, beside the mine. It was designated an historical place in the 1930s and more recently was moved into Cobalt from the mine site, near Kerr Lake.
| Farah Mining Company Limited Lat. 47º 23’ 06” Long. 79º 39’ 20” | 8,952 | |
| Foster Cobalt Mining Company Limited Lat. 47º 22’ 22” Long. 79º 39’ 57” | 1,159,390 | 457,574 |
| Hargrave Silver Mines Lat. 47º 22’ 18” Long. 79º 39’ 14” | 506,927 | 6,424 |
| Hiho Mine See Kerr Lake Mining Company | ||
| Hudson Bay Mine Lat. 47º 24’ 15” Long. 79º 41’ 12” | 6,452,266 | 185,739 |
| Juno Metals Corp. Lat. 47º 22’ 59” Long. 79º 39’ 40” | 46,391 | |
| Kerr Lake Mining Company Lat. 47º 22‘ 31” Long. 79º 39’ 29” | 28,502,037 | 650,679 |
This property was worked by a number of companies over the years but famously by the Hiho Silver Mines Limited. Specimens may be referred to as coming from the Hiho Mine.
| King Edward Mining Company Lat. 47º 23’ 33” Long. 79º 38’ 20” | 1,294,233 | 650,679 |
Was also referred to as the Watts Mine in the earliest days of Cobalt.
| La Rose Mines Limited Lat. 47º 24’ 00” Long. 79º 40’ 33” | 26,283,372 | 1,010,720 |
Named for the railroad blacksmith, Fred La Rose, who is credited with finding the first silver at Cobalt. Fred’s original blacksmith shop still stands near the mine site. Since the veins were exposed on the cliff faces at the north end of Cobalt, they are prominent to this day.
| Lawson Mine Lat. 47º 22’ 26” Long. 79º 39’ 41” | 4,213,513 |
One of the veins mined on this property was the famous “Silver Sidewalk”, so called because the surface expression of the vein was almost 1000 feet long and appeared to be a width of about 6-8 inches of largely solid silver.
| Little Nipissing Claim JB2 Lat. 47º 23’ 08” Long. 79º 41’ 44” | 82,000 | |
| Lumsden Claim (See Brady Lake Property) | ||
| Mayfair Mines Limited Lat. 47º 20’ 44” Long. 79º 38’ 36” | 26,240 | |
| McKinley-Darragh Savage Mines Lat. 47º 23’ 19” Long. 79º 41’ 28” | 17,300,000 | 465,582 |
Named for the two men who staked the first claim in the Cobalt Mining Camp. Usually referred to as the McKinley-Darragh Mine.
| Mensilvo Mines Limited Lat. 47º 22’ 29” Long. 79º 40’ 55” | 374,824 | 149,643 |
| Nancy-Helen Mines Limited Lat. 47º 23’ 40” Long. 79º 41’ 26” | 91,770 | |
| Nerlip Mines Limited Lat. 47º 23’ 56” Long. 79º 39’ 09” | 911 | 2,949 |
| New Bailey Mines Limited Lat. 47º 22’ 20” Long. 79º 40’ 14” | 3,131,352 | 76,849 |
Also, popularly known as the “Glen Lake Mine” today. Excellent high grade silver-cobalt ore can still be found in the old dumps at this property.
Nipissing Mines Limited
| Claim 404 Lat. 47º 23’ 33” Long. 79º 40’ 53” | 91,796,735 | 5,641,757 |
| Claim 406 Lat. 47º 22’ 49” Long. 79º 41’ 17” | 1,236,879 | 74,036 |
| Claim 407 Lat. 47º 22’ 51” Long. 79º 40’ 28” | 1,843,633 | 157,738 |
Most mines of the Cobalt area were each located on a single claim or portion of a claim. The Nipissing mine property however was originally staked as four claims, on some of the richest ground in the Cobalt Camp. This explains the extensive workings and large mill site of “the Big Nip”. The many mine dumps have been the source of some nice high grade silver and silver leaf over the years. As well, because of the concentration of veins on the property, very good “Glacial Float” has been located by collectors with metal detectors. These claims were eventually all acquired by Agnico mines and operated along with other claims from the 1960s until the 1980s.
| Nova Scotia Silver Mining Company Lat. 47º 23’ 14” Long. 79º 39’ 44” | 1,082,774 | 114,301 |
| M.J. O’Brien Lat. 47º 23’ 57” Long. 79º 40’ 06” | 43,739,820 | 3,124,504 |
The O’Brien mine yielded some amazing high grade in its heyday. Some of this material escaped the miners and can still be found to this day on mine dumps. As well, the O’Brien had zones that produced good crystals of acanthite pseudomorphs after argentite, proustite and other secondary silver minerals. If collectors encounter well-crystallized specimens of such minerals from this (or any others) mine, they are no doubt very old specimens from the actual mining operations.
| Pan Silver Claim (see Brady Lake Property) | ||
| Penn Canadian Mines Limited Lat. 47º 22’ 32” Long. 79º 40’ 16” | 4,418,802 | 190,821 |
| Peterson Lake Silver-Cobalt Mining Company Limited (Peterson Lake) Lat. 47º 23’ 16” Long. 79º 40’ 33” | 918,076 | 27,328 |
| Peterson Lake Silver-Cobalt Mining Company Limited (Cart Lake) Lat. 47º 22’ 52” Long. 79º 41’ 02” | 5,711,490 | 7,787 |
| Princess Claim Lat. 47º 23’ 16” Long. 79º 41’ 44” | 3,713,806 | |
| Red Jacket Property Lat. 47º 22’ 36” Long. 79º 42’ 20” | 3 | 355 |
| Reinhardt Cross Lake Group Lat. 47º 23’ 26” Long. 79º 38’ 44” | 278,631 | 2,535 |
| Right of Way Mines Limited North Mine Lat. 47º 23’ 52” Long. 79º 40’ 43” | 2,969,195 | 41,811 |
| South Mine Lat. 47º 23’ 22” Long. 79º 41’ 35” |
The Right of Way mine was one of the most prominent mines in Cobalt since it is right beside the railway, in the middle of town. The head frame (North Mine) still stands, today.
| Rochester Claim (see Brady Lake Property) | ||
| Savage Mine (McKinley Darragh) Lat. 47º 23’ 19” Long. 79º 41’ 28” | 4,500,000 | 465,582 |
This mine and the McKinley Darragh mine were both operated by the same company, McKinley Darragh-Savage Mines Limited, during the hey-days of Cobalt from 1903 onwards.
| Silver Cliff Mining Company Limited Lat. 47º 23’ 40” Long. 79º 39’ 20” | 535,246 | 9,323 |
| Silver Cross Cobalt Mining Company Ltd Lat. 47º 22’ 54” Long. 79º 38’ 45” | 3,091 | |
| Silverfields Mine See Alexandra Silver Mining Company | ||
| Silver Leaf Mining Company Ltd Lat. 47º 22’ 33” Long. 79º 39’ 38” | 495,443 | 1,208 |
| Silver Miller Mines Ltd. Lat. 47º 23’ 53” Long. 79º 40’ 36” | 2,030,000 |
This company operated the Brady Lake Property for a number of years. Some specimens may be attributed to Silver Miller mine.
| Smith Cobalt Mines Limited Lat. 47º 23’ 26” Long. 79º 38’ 19” | 456 | |
| Timiskaming Mining Company Limited Lat. 47º 21’ 40” Long. 79º 38’ 27” | 12,118,796 | 202,869 |
This mine has been a very good producer of high grade silver, using metal detectors, over the years.
See Beaver mine for additional info on the Timiskaming.
| Trethewey Silver Cobalt Mines Limited Lat. 47º 24’ 01” Long. 79º 41’ 09” | 7,256,470 | 216,392 |
| University Mines Limited Lat. 47º 22’ 12” Long. 79º 40’ 15” | 790,000 | 82,681 |
| Violet Mining Company Limited Lat. 47º 23’ 52” Long. 79º 39’ 42” | 897,291 |
| Cleopatra Mining Company Limited Lat. 47º 22’ 10” Long. 79º 40’ 29” | 2,160,356 | 136,069 |
Good high grade has been found in recent years in waste dumps around this old mine.
| Provincial Mine Lat. 47º 22’ 36” Long. 79º 41’ 11” | 286,897 | 54,522 |
Interestingly this claim was put aside by the government of Ontario to be mined by a government-controlled company “for the people” something unusual for the time. The mine was opened but operated for only a short time before the ore ran out. It was a money losing venture. The government turned it over to a private company who also failed to make it go.
| Waldman Silver Mines Limited Lat. 47º 22’ 17” Long. 79º 41’ 08” | 33,525 | 2,068 |
| Wyandoh Silver Mines Limited Lat. 47º 22’ 16” Long. 79º 41’ 03” | 33,699 | 1,235 |
| Agaunico and Reuthel mine Lat. 47º 25’ 08” Long. 79º 36’ 17” | 980,000 | 4,353,909 |
The “Agaunico” in this mine's name supposedly stands for Ag-Silver, Au –gold, Ni –nickel and Co –cobalt. The gold may have been wishful thinking. Purportedly, some gold was found at this mine.
| Cobalt Contact mine Lat. 47º 24’ 55” Long. 79º 36’ 59” | 26,000 | 31,028 |
| Dotsee mine Lat. 47º 25’ 41” Long. 79º 45’ 16” | 125 | 8,007 |
| Genesee Mining Company Lat. 47º 24’ 30” Long. 79º 40’ 21” | 69,404 | 12,079 |
| Green-Meehan and Red Rock mine Lat. 47º 24’ 54” Long. 79º 37’ 10” | 498,000 | 27,024 |
| Harrison-Hibbert and Ruby mine Lat. 47º 24’ 53” Long. 79º 37’ 32” | 876,500 | 214,792 |
| North Cobalt and Hunter mine Lat. 47º 25’ 16” Long. 79º 37’ 30” | 1,453 |
| Casey Cobalt-Silver Mines Limited Lat. 47º 34’ 53” Long. 79º 34’ 48” | 10,094,801 | 384,157 |
Also popularly referred to as the Langis mine, after the Langis Silver and Cobalt Mining Company, a company which operated it for a while during the 1960s. The Langis has been the source of some of the best dendritic silver, high-grade ore. Specimens often consist of chunks of ore, sawn to reveal intricate “herringbone” patterns of silver crystals, usually coated with arsenide minerals in carbonate vein material. Sometimes the carbonates can be leached away with acid to reveal excellent herringbone crystal structures. The Langis mine is located on an isolated patch of Cobalt sediments and Nipissing diabase about 12 miles north of Cobalt, at the north end of Lake Temiskaming, near New Liskeard.
| Harmak Mining Company Lat. 47º 34’ 34” Long. 79º 35’ 01” | 4,625 | 12,937 |
| Lang Caswell Mine Lat. 47º 34’ 34” Long. 79º 35’ 01” | 1,503 | 4,932 |
Elk Lake Area
| Roy Silver Mines Limited Lat. 47º 46’ 59” Long. 80º 27’ 46” | 1,888 |
| Ethel Copper Mines Limited Lat. 47º 44’ 53” Long. 80º 16’ 29” | 6,061 | |
| Moose Horn Mines Limited Lat. 47º 44’ 17” Long. 80º 18’ 46” |
The Moose Horn mine was not a prolific silver producer. Only a few tons of silver ore, rich in nickeline were ever shipped. However, the Moose Horn mine was the source of Temiskamite, Ni11As8, which was proposed as a new mineral and was, in fact, a new mineral. Unfortunately, German scientists had characterized maucherite just prior to the characterization of Temiskamite and thus the name maucherite took priority. Temiskamite was subsequently discredited.
| Mother-Lode Mining Company Limited Lat. 47º 44’ 39” Long. 80º 21’ 29” | 1,581 |
| Mapes-Johnston Mining Company Limited Lat. 47º 44’ 16” Long. 80º 26’ 19” | 1,000 | 870 |
| Otisse Mining Company Lat. 47º 43’ 16” Long. 80º 26’ 32” | 2,380 | 26 |
| Shane-Darragh Claim W.D. 904 Lat. 47º 43’ 15” Long. 80º 25’ 20” | 63,417 | 1,214 |
| Lucky Godfrey Silver mines Lat. 47º 39’ 46” Long. 80º 16’ 54” | 9,835 | 593 |
| Cane Silver Mines Limited Lat. 47º 36’ 11” Long. 80º 01’ 29” | 3,100 |
| White Reserve Mines Limited Lat. 47º 26’ 22” Long. 80º 16’ 47” | 19,775 | 452 |
Gowganda Area
The Capitol mine has been a favorite collecting locality for collectors with metal detectors and has produced many fine specimens of dendritic silver ore over the years. Much bulldozer work was done on the dumps and grounds of this property in 2012, which revealed large amounts of high-grade silver ore, much of which has been recovered by collectors with metal detectors. Excellent potential there.
| Castle-Trethewey mine Lat. 47º 40’ 45” Long. 80º 44’ 27” | 9,410,095 | 376,392 |
The “Castle mine”, as it is usually known, still yields nice high-grade and crystallized silver specimens today.
| Miller Lake Everett mine Lat. 47º 40’ 41” Long. 80º 44’ 38” | 3,461 | |
| Millerett mine Lat. 47º 40’ 16” Long. 80º 44’ 34” | 611,822 | 5,004 |
| Bishop, Caleta & Keora mine Lat. 47º 39’ 22” Long. 80º 39’ 28” | 42,400 |
| Hudson Bay Silver Mines Limited Lat. 47º 30’ 47” Long. 80º 48’ 17” | 80,186 | 567 |
This mine, also known as the Rustex mine and Rusty Lake mine, has produced superb specimens of skutterudite. The skutterudite occurs as crystals in calcite veins, with silver and other arsenides. The calcite can be removed with acid to reveal clusters of sharp, lustrous skutterudite with crystals to 0.5 inches in size.
| Bartlett mine Lat. 47º 35’ 49” Long. 80º 48’ 46” | 20,219 | 18 |
| Mann/ Boyd Gordon mine Lat. 47º 37’ 16” Long. 80º 48’ 57” | 123,620 |
Specimens of branching silver crystals in oxidized arsenides have been found over the years at this mine. These specimens are usually said to be from the Manridge mine after Manridge Mines Limited, a company that operated it as well as the Bartlett, Boyd Gordon mines, Reeve-Dobie, South Bay and Welch mines.
| Reeve-Dobie mine Lat. 47º 36’ 11” Long. 80º 48’ 50” | 88,584 | |
| South Bay mine Lat. 47º 35’ 31” Long. 80º 48’ 10” | 1,500 | |
| Welch mine Lat. 47º 35’ 57” Long. 80º 48’ 57” | 1,000 |
| Miller Lake O’Brien mine Lat. 47º 39’ 58” Long. 80º 44’ 01” | 43,181,431 | 787,350 |
This mine has been a source of rich high grade, found with metal detectors.
| Morrisson mine Lat. 47º 39’ 10” Long. 80º 42’ 54” | 719,522 | 22,064 |
| Walsh mine Lat. 47º 39’ 30” Long. 80º 43’ 39” | 453,424 | 3,563 |
Silver Centre Area
The “Woods Vein” of this rich silver producer was also a prolific specimen producer. Most of the mines in the Cobalt area did not contain many open vugs where proustite, wire silver and other rare silver minerals could form. According to Sergiades, 1968, pg. 428, “Pre-glacial weathering on part of the Woods vein extends to 480’ depth; ore deposition in consequence is partly secondary and the vein vuggy.” The collection of the Royal Ontario Museum has excellent specimens of wire silver from the Keeley and Frontier mine as well as superb proustite specimens with well formed crystals to 0.75 inches.
This was a rich mine and superb examples of high-grade ore have been found in the waste dumps with metal detectors.
Note about Silver Centre: When the South Lorrain Silver Mining area was booming starting in 1907, a town called Silver Centre was established. It was a proper town, with a well laid out town site and with great hopes for the future. Unfortunately it did not last. It is considered the area’s “ghost town” and remnants of Silver Centre may still be encountered in what is now wilderness, again. It is mentioned here since collectors may very well run into this name on labels or in writings on the Cobalt area. Interestingly, there is still a road sign in North Cobalt that points people in the right direction and distance for Silver Centre.
