By David K. Joyce, Newmarket, Ontario and Roger Poulin, Val Caron, Ontario
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.
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!
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.)
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 occurs in limited occurrences in the Sudbury Structure. Some very long crystals, associated with pyrrhotite and cubanite were collected at the Strathcona Mine.
Fluorapophyllite occurs in the N-W tension fractures that cut through the Sudbury Structure.
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 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.
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 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.
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.
Native copper occurred only at the Vermillion Mine in Denison Township, in flat, dendritic crystal groups to 5mm in rock fractures.
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 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.
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.
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 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 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.
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 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.
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 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 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 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 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 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 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.
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.
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.