Search Documents

By A. T. GRIFFIS, R. J. GRIFFIS

A large magnesite-talc body is locared in Delora Township, 11 km sourh-southeasr of Timmins, Onrario. The deposit occurs in part of an Archean greensrone belt dominated by volcanic and sedimenrary rocks and large bodies of ultramafic intrusions. The magnesite-talc zane is abour 1800 m long, has a maximum width of 300 m and has been drilled ro 120 m below surface. Chemical analyses of rhe main carbonate zane average 20 ro 28% soluble MgO (magnesia), 5 ro 6% rota/ iron oxide and less rhan 0.1 % CaO (lime). Mineralogically, the zane consists of approximately 54% magnesite, 28% rate, /5% quartz and 3% hematire. Perrographic srudies suggest that rhe various assemblages of magnesite, rate, quartz and serpentine were derived from a parenr serpenrinire (after dunire). An early carbonitization stage, which produced a high-magnesite, low-talc assemblage, preceded a farer decarbonitizarion stage, which formed rhe main magnesite-talc assemblage. Despite a favourably low calcium oxide content of rhe magnesite-talc rock, considerable iron in the magnesire /at rice has limited the quality of the beneficiared product: rhe besr flotation concentrate to dare yields 92 to 94% dead-burned MgO. Experimen- I L t r i i c:~:.•-4- -------- ? -_;> ,•----1---- ta/ work continues on finding a process whereby high-purity magnesia can be produced on a commercial scale.

Jan 1, 1984

By Matthew Violot

Introduction ?Located off highway 6, approximately 5 km, SW of Thompson, Manitoba ?Base metal mine: Nickel? Maximum Depth: 4100 ft ?Started Production in 1966 (INCO, 2006)?Halted in 1978?Re-opened in 1989 ?Two types of mining:?VBM (vertical block mining)?Cut and Fill 1.1 Problem ?Birchtree mine is experiencing failures and undesirable dilution in some of their stopes. ?Time can have a large effect on open stopestability. ?Birchtreeis interested in how time is affecting the stability of their stopes. ?The study focuses on the lower 84 complex, which extends from 2750 to 4100 foot level.

Nov 1, 2011

By G. Dubé, A. Leclerc, P. Quinn, G. E. Agar, J. Y. Clouthiér, J. D. McLaughlin

"Gold dissolution by cyanide requires the presence of oxygen which is usually supplied by sparging compressed air into the gold containing slurry. For those ores that contain certain obnoxious substances that consume oxygen, maintaining the required minimum level of dissolved oxygen can be troublesome. One of the most economical solutions to the problem of low dissolved oxygen, especially in plants that have air compressors installed, is to enhance the rate of oxygen mass transfer.The oxygen mass transfer rate was measured in a two phase system using two different sparger arrangements, and with addition of a frother that is known to reduce the bubble size produced by the sparger. The common sparger system was shown to be inefficient compared to a readily available but under utilized method of gas dispersion which introduces air directly below the reactor turbine. Transfer of this technology to an operating plant confirmed the beneficial effect of the improved sparger system. The addition of the frother did decrease the bubble size, but it also reduced the oxygen mass transfer rate."

Jan 1, 1993

By David L. Anderson

"The government o f Canada has, since 1981, been under intense political pressure to modify its foreign direct investment (FOI) regulatory regime(1). To date the government's response has been limited to administrative and ""cosmetic"" changes: substantive issues have been largely ignored(2). However, as long as the economy continues to flounder , the Foreign Investment Review Agency (FIRA), as it is presently formulated , will continue to be an easy target for government critics . This phenomenon, in conjunction with the virtual certainty of a federal general election within two years, suggests that changes to the FIR Act will be seriously entertained by the present government.Recent events indicate that if change s are made, they will likely entail the adoption of a special-sector approach within the existing framework of a general screening system(3). Since this approach is currently employed in Australia(4), it would seem to be appropriate, from a public policy perspective to study that country's experience in developing and operating such a scheme. In doing so, I shall focus on the mineral sector; the rationale for doing so is as follows. First, this sector served as the focal point of the Australian FOI regulatory debater(5), Second , with the exception of the oil and gas industries, the non-petroleum mineral sector is one of the few areas of the Canadian economy wherein the Trudeau government has adopted an explicit domestic ownership target(6). Third, the non-petroleum mineral sector is, undoubtedly, a prime candidate to be denoted a s a special-sector if such a framework were to be utilized by the Canadian government!"".Although international comparisons are fraught with danger , a Canadian/Australian comparison is particularly appropriate(8). Both countries have reasonably similar economic, political and social structures . Furthermore, as noted above , Australia is the only other western country which employs a general screening mechanism for FOI. In addition, it utilizes a special area approach ; within this scheme, an explicit target of a minimum of 50% Australian ownership of all new resource projects has been formulated and clearly promulgated to all of the relevant interest groups. This policy, broadly defined, has been in place for more than six years and during this time the Australian mineral sector has, by world standards, prospered(9). Hence, the Australian experience in designating the mineral sector as a key area within a general screening system, should be of interest to Canadian policy-makers."

Jan 1, 1984

By John D. Godfrey

Geological mapping on the Canadian Shield in northeastern Alberta outlined severalgranitoid rock massespotentially suitable as building stone. A particularly attractive prospect, the Chipewyan Red Granite, was subjected to an aerial survey and ground check. The petrologic and fracture characteristics critical for quarrying and use as a building stone were assessed in the course of detailed mapping at two of the most favourable sites. The extension of good rock was tested to shallow depths at one site by shallow diamond-drill coring. , The Chipewyan Red Granite displays a warm red colour, medium grain size and fairly massive texture, and takes a good polish. Deleterious geologic features studied in outcrop and subjected to structural analysis included regular joint systems, quartz veins, pegmatite dykes, basic shear zones and fault zones. Many of these key geologic features are systematic and hence predictable for stone quarrying purposes; other features, such as irregular fracelM tures, are non-systematic and arefar less predictable. The megascopic structural features studied show similar preferred orientations which appear to be collectively related to the tectonic history.

Jan 1, 1979

By Andrea M. Ouchi

A major focus of ground control research presently being conducted by the Geomechanics Group in the University of British Columbia Mining Engineering Department is to incorporate weak rock masses (RMR76 less than 50) into existing empirical design relationships. An emphasis is being placed upon the updated span design curve/critical span graph originally developed at UBC. The original database has been augmented by mapping of one mine in Montana and of several mines within the Carlin and Getchell Trends of Nevada. In addition, a neural network analysis has been performed and modifications of the span design curves at the lower RMR76 range have been made. The common factor in all the above mentioned mines is a weak back and/or walls. In most cases, the ore zone is the weakest rock unit and must be dealt with to safely extract the mineral bearing rock. This work attempts to provide rock mechanic tools that will enable a mine operator to make economic decisions that will also ensure a safe working environment.

May 1, 2004

By D. A. Bordin, C. J. Newman, R. J. St. Eloi

"The requirements for a metallurgical acid plant treating smelter gases are both unique and demanding in terms of sulphur dioxide treatment and emission control. Since start up in 1981, the copper smelter at the Kidd Creek Division of Falconbridge Limited has undergone several major expansions. The expansion and modification of the acid plant has been an integral part of this process. Both production demands and government regulations dictate that this metallurgical acid plant be unique in terms of operating flexibility. The variable capacity to treat a wide range of sulphur dioxide concentrations, and the operating flexibility to control emissions are the topics of this paper.INTRODUCTIONThe Kidd Creek Division of Falconbridge Limitied is a base metal mining and metallurgical complex located in Timmins, Ontario. The discovery of the original copper-zinc-silver orebody was announced in April, 1964. Mining operations began in 1966 with a 9000 tonne per day concentrator coming on stream in November of that year. In April 1972, a 108 000 tonne per year zinc plant was commissioned. Over the years the facilities have been expanded, such that the concentrator now has the capacity to process 13 000 tonnes of ore per day . To expand zinc production, the world's second installation of the Cominco/Sherritt pressure leaching facility was completed in 1983 to bring total zinc production capacity to 125 000 tonnes per year. In 1973, serious planning for a smelter operation began. In early 1975, after studying both continuous smelting and flash smelting processes, a decision was made to proceed with the technology offered by Mitsubishi Metal Corporation of Japan. The Mitsubishi Continuous Smelting Process was to be used for the smelter and the Onahama No.3 tankhouse technology for the copper refinery.The smelter, which uses the Mitsubishi Continuous Smelting Process for the continuous production of blister copper from concentrate, went on line in June 1981. It has been expanded from its original capacity of 60 000 tonnes to 100 000 tonnes per year of copper.From the very early design stages for the metallurgical complex, the company had adopted a policy of constructing and operating modern plants which would meet existing and anticipated environmental standards. With this in mind, the decision was made to utilize the proven technology of fixing sulphur dioxide emissions, in the form of sulphuric acid. A 636 tonne per day single absorption contact acid plant was built to serve the zinc plant in 1972. In 1981, an 883 tonne per day double absorption contact plant was built to serve the needs of the copper smelter. The copper smelter acid plant has since been expanded to a design capacity of 1692 tonnes per day and it is the main focus of this paper."

Jan 1, 1989

By Claude Bazin

"Laboratory semi-batch flotation tests were conducted using two different sulphide ore samples. The size reduction was adjusted to cover a wide range of flotation feed size distributions. Results show that similar recoveries can be achieved independently of the fineness of grind. This result suggests that possible energy savings could be achieved by a redistribution of the power between the grinding and regrinding mills. The behaviour of the selectivity curves shows that some gangue minerals are more sensitive to particle size than other ones, implying the existence of preferential associations between minerals in the ore.INTRODUCTIONInteractions between grinding and flotation have been studied for many years, and still a robust model to link the two processes lacks to be developed (Girard et al., 2005; Bazin et al., 2001). The ore size reduction liberates mineral grains, while flotation separates them into valuable minerals and gangue. The more size reduction that is applied to the ore the more important is the mineral liberation but also the production of fine particles that can pose problems during flotation (Trahar and Warren, 1976). The definition of the grinding requirement for flotation is a complex problem (Rickelton and Dell, 1977; Sosa Blanca et al., 2000; Morrison, 1993; Wei and Gay, 1999).This paper analyzes the effect of the fineness of grind using semi-batch flotation test results. The first two sections describe the test procedure and the results. The third section analyzes the results in terms of liberation and selectivity, and proposes a possible redistribution of power between grinding and regrinding mills."

Jan 1, 2006

By G. R. Morin, A. R. Leggett

"In 2010, closure of the Kidd metallurgical plants along with structural changes to the historical ratios of payable metals led to a review of the operating targets at the Kidd concentrator. Previous operating data indicated that there was potential for significant revenue improvements by lowering the copper concentrate grade. An extended plant trial was carried out in 2011 to quantify the revenue impact of lowering the copper concentrate grade from 27% to 25% Cu, as well as identifying the lower practical grade limit. Analysis of plant trial results indicated that the process change increased net concentrate revenue by $2 M to $3 M per year at current metal prices. Increased revenue was primarily associated with higher silver recovery to the copper concentrate while the marginally improved copper recovery was essentially offset by increased zinc losses and concentrate treatment and freight charges.Details of the plant test work results are discussed in this paper along with the financial analysis of the revenue improvements. Key areas covered are major revenue components of the concentrate contracts, validation of revenue improvements through plant testing and sensitivity of the improvements to market and plant variables.INTRODUCTIONThe Xstrata Copper Kidd concentrator commenced operations in 1966 treating ore from the nearby Kidd volcanogenic massive sulphide deposit in Timmins, Ontario (Thompson, Amsden, & Chapman, 1978). Over the years, up to four separate grinding-flotation divisions were in operation with throughput rates peaking at 4.5 million tonnes per year of ore in the mid 1980’s (Kelebek & Francis, 1998). As the mine production decreased and grinding throughput increased operations were gradually cut back and since 1998 two grinding-flotation divisions have been in operation treating Kidd mine ore. One of the idled divisions has been intermittently used for custom milling operations, most recently the Ni/Cu Montcalm deposit, which was milled from 2004 to 2009. Current budget throughput rates, limited by mine production, are 2.4 million tonnes per year of ore grading 1.7% Cu, 4.3% Zn and 55 g/mt Ag. Concentrate production rates are 150,000 tonnes per year of copper concentrate and 155,000 tonnes per year of zinc concentrate. The Kidd mine is the deepest base metal mine in the world with mining operations down to 9600 ft.In 2010 the copper and zinc plants at the Kidd metallurgical site, which previously treated the concentrate production from the Kidd concentrator, ceased operation due to a variety of economic and market factors. Following the metallurgical plant closures the Kidd concentrator products were shipped off site for treatment. The majority of the copper concentrate is now processed at the Xstrata Copper Horne smelter in Rouyn-Noranda, Quebec with the majority of the zinc concentrate processed at Canadian Electrolytic Zinc Ltd. in Valleyfield, Quebec."

Jan 1, 2013

By Chuck Edwards

"Milling operations in northern Saskatchewan’s Athabasca Basin have produced uranium continuously since 1975. Over that period, the Athabasca Basin has been one of the world’s premier uranium camps, yielding more than 660 million lb of U3O8. In this paper, the author describes former and current milling operations and discusses why and how the milling process has changed and developed over the past 35 years. The author’s considerations for the future of uranium extraction in the Athabasca Basin close out the paper.INTRODUCTIONThe roughly oval Athabasca Basin in northern Saskatchewan occupies nearly one third of the surface area of the Saskatchewan Shield. Its sandstone-like deposits lie unconformably on the older basement. The basin hosts many high-grade unconformity-type uranium deposits(Saskatchewan Energy and Resources, 2010) for which the Athabasca Basin is world famous. Uranium production in the Athabasca Basin has come from four mills. In the order of startup these are Rabbit Lake, Cluff Lake, Key Lake and McClean Lake. General data (AREVA, 2010; Cameco, 2010; Denison 2010) for each mill are shown in Table 1."

Jan 1, 2011

By D. C. Fraser

Copper occurs invisibly in a geo-logical environment characterized by swampy conditions and an accumulation of forest peat. This swamp, located in southeastern New Brunswick, contains up to ten per cent cop-per (dry weight), in the organic sediments. This occurrence appears unique in that the metal is apparently organically combined in a chelate compound. Unlike the acidic nature of most peat bogs, the pH of the cup-riferous peat is nearly neutral. Analyses of the peat and associated soils have indicated that the bulk of the copper is contained in the organic sediments. It appears that the cop-per distribution is affected by capillarity, evaporation and the growth of frost crystals, and that the copper fixation is effected by organic sequestration resulting in the metal being bound to the nitrogen or oxygen components of the forest peat. While such a fixation mechanism is not definitely established as responsible for the immobilization of the metal, the facts at hand are compatible with

Jan 1, 1961

By Gilles Bonin

Structures and serpentinization patterns in the Thetford Mines peridotites are important characteristics indicating the necessary geological conditions which led to the development of chrysotile orebodies in Early Ordovician limes. These structures and serpentinization patterns are reviewed in this paper using the geology of LAB Chrysotile orebodies as a model. Structural aspects include parallel and transverse faults, parallel and transverse granite slabs, and orebodies, some of which trend clearly north-westward parallel to the accretionarymovement. Serpentinization patterns in the peridotite belt, particularly in the harzburgite, include primary pervasive mass serpentinization and secondary complete serpentinization. Listwaenites layers appeared along some faults and along some granite slabs as a result of hydrothermal alteration of the serpentine, following the emplacement of the devonian plutons to the south. These plutons as we/1 as other important lineaments, align with the structural pattern of Thetford Mines ophiolites. It is believed that these plutons are part of a heavy magma tic corridor resembling the Pilote-Mont-Louis corridor in the Gaspe (Doyon and Berger, 1997), and the Buchans' structure in Newfoundland (Hutchinson, 1984), both intersecting the Brompton-Baie Verte line.

Jan 1, 2001

By Jaime V. Ongpin

"The author will give a capsule history of Benguet Corporation and attempt to identify its operating environment and underlying ""strategy"" until 1974, when the company's management assumed office. The company's operating environment and ""interim strategy"" from 1975 to 1980 will be described. The discussion will cover an environmental forecast and define the company's"" strategy for survival"" for the balance of this century.IntroductionIn December last year, I was asked to deliver a pa per for the management lecture series a t the Asian Institute of Management in Manila. The paper was entitled "" The 1970's: A Decade of Disaster For New Mining Projects"" . In that paper, it was my task to review the results of new mining projects in the Philippines during the previous decade. The task was not a happy one, for the results themselves were not only unhappy, but disastrous on a scale unprecedented in Philippine history. Out of a total of 17 major mining project s involving an aggregate capital investment in excess o f US $2 billion during the 1970s, only three project s have been profitable, and all the rest have either gone "" belly up"" or are teetering on the very edge of financial disaster.It is in the context of this shocking record of widespread financial dislocation in the Philippine mining industry, (which in varying degrees appears to have been paralleled in virtually every other country in the world where mining is an important sector of the economy) that I address myself tonight to the theme of this symposium. My paper is entitled ""Risk Management Strategy in Mining"" and it is sub titled ""Can Benguet Corporation Survive to Celebrate its Centennial in 2003?"". I have inserted the word ""Strategy"" and added the subtitle, because I wish to make it clear first, that my presentation to you tonight will be focused exclusively on the strategic aspect s of risk management, and second that I will limit myself to Benguet's own ""in-house"" experience and perspectives on this subject. I would caution you therefore, to consider my views within this restricted framework, and in light of the particular and sometimes peculiar circumstances within which Benguet Corporation operates."

Jan 1, 1983

By Stephen P. Quin

One of the most prospective undeveloped greenstone belts in Canada, the Hope Bay greenstone belt extends over 80km in a north-south direction and is between 7 and 20km wide. The belt lies on the arctic coast and comprises mafic meta-volcanic and meta-sedimentary rocks that are bounded by Archean granite intrusives and gneisses. The greenstone package has been deformed during multiple events and is transected by major northsouth trending shear zones that appear to exert a significant control on the localization of mineralization. The Hope Bay belt contains a number of significant gold deposits hosted in a typical Archean greenstone belt and which occur in several geologic settings, including shear-hosted, lode-style and breccia-associated. Combined, the deposits host a measured and indicated resource of 1.6 million oz of gold averaging 15.7 g/t plus an inferred resource of 2.7 million oz of gold averaging 12.3 g/t. All deposits remain open to expansion. Exploration in the period 2000-2002 by Miramar includes more than 110,000m of drilling to more fully define the nature of the known deposits, while regional exploration has focused on identifying and evaluating new targets. In carrying out its programs, Miramar uses a number of techniques to improve its chances of exploration success. Activity in 2003 includes 43,000m of drilling focused on expanding resources in the Madrid area, testing the Boston deposit at depth and continuing the hunt for more discoveries. Meanwhile Miramar is advancing one of the deposits towards a production decision, based on a low capital, high return development scenario.

May 1, 2003

By Ike Isagon

Outline 1.Background Sudbury Backfill Operations 2.Alternative Binder 3.Alternative Binder Trial Process Flow Diagram ?Laboratory Results ?Plant Trial ?Final Evaluation and Approval ?Management of Change (MOC) 4.Economics 5.Conclusion 6.References and Acknowledgements

Nov 1, 2011

By J. J. Brummer

"A reconnaissance geochemical survey, using the stream sediment technique, is described. The survey covered an area of about 400 square miles, in the Seal Lake area of central Labrador, underlain by basaltic flows, diabase and metadiabase sills, and sedimentary rocks. Previous work had indicated numerous small copper occurrences within the Seal Lake group of rocks. Stream sediments were tested for the readily extractable copper content and total heavy metal content. The results of the copper survey did not yield any new data on the distribution of copper mineralization. Results of the total heavy metal survey attracted attention to a remote portion of the area (Ten Mile Lake), which had hitherto been regarded as having no economic interest. The anomalous values found, suggested that zinc mineralization should occur in this region. Geological mapping indicated that the rocks exposed belonged to the Letitia Lake Group, which is older than the Seal Lake Group exposed to the east, which contains the copper mineralization of the district.Investigation of the area lead to the discovery of: (1) uneconomic lead-zinc mineralization; (2) radioactivity extending over a considerable area. Evaluation of the radioactive rocks led to the discovery of columbium-thorium mineralization in amphibolite and in diopside-actinolite schists along a contact with intrusive alkali syenite.Thus a geochemical survey, which was planned to evaluate a copper province, resulted in the discovery of lead-zinc-columbium-thorium mineralization."

Jan 1, 1960

By R. Q. Honaker

It has been shown that naturally hydrophobic carbonaceous materials such as coal and graphite can be selectively coagulated and separated from hydrophilic impurities without using oily agglomerants, flocculants or electrolytes. The coagulation occurs at C-potentials significantly higher than those predicted by the classical DLVO theory, suggesting that it is driven by the hydrophobic interaction. In the present work, the energy barriers for the coagulation of a hydrophobic coal sample have been calculated using the extended DLVO theory which incorporates the hydrophobic interaction energy in addition to the dispersion and the electrostatic energies. For the coagulation of minerals present in the coal, the classical DLVO theory has been used for the energy barrier calculation. The results of these calculations provide an excellent correlation with the results of a series of Selective Hydrophobic Coagulation (SHC) tests conducted with run-of-mine coal and graphite samples.

Jan 1, 2004

By R. H. Brooks

Blasthole stoping methods were introduced at Birchtree Mine as an alternative to the original cut-and-fill and shrinkage stoping methods. The object was to take advantage of the ore structure and conditions, and achieve increased productivity. This paper outlines the design, operation and economics of three areas which utilized blasthole stoping. The 108areafrom 2300 level to 1500level was converted from cut-and-fill to sublevel blasthole stoping based on a block mining-and-filling sequence. The second area, the crown pillar of 110 mechanized cut-and-fill stope below 500 level, was recovered using horizontal rings drilled from raises within the ore zone. The third area, the 83 orebody from 1300 level to 1100 level, used the vertical crater retreat (VCR) method with large-diameter blastholes. Blasthole stoping has increased productivity and improved operating conditions.

Jan 1, 1979

By Allen Chung, John Twomey, Christopher J. Greet

"It is widely accepted that the type of grinding media has an impact on the grinding chemistry and subsequent flotation behaviour of the sulphide minerals being separated. There are countless laboratory investigations demonstrating that inert grinding media produces more oxidising pulp potentials, reduced levels of grinding media corrosion products and superior concentrate grades and valuable metal recoveries. However, taking these results to industrial scale has proven difficult.Work conducted at the Ernest Henry Mine, in north western Queensland, Australia, at laboratory and pilot plant scale clearly indicated that using a high chrome grinding media resulted in significant improvements in both copper and gold recoveries. However, advancing this work to plant trial represented considerable financial and technical risk to the mine.This paper provides details of the protocol developed and used during the high chrome grinding media plant trial. It describes the test regime employed to measure changes in pulp chemistry, and the statistical methodology utilised to interpret the results. The work also highlighted the need for close cooperation between the metallurgists on site and the researchers conducting the trial.To date, the trial has produced excellent results: indicating that the copper recovery has improved by about 2 percent. The successful application of high chrome grinding media to the Ernest Henry ore has increased metal value by $18.7 million USD per annum based on current spot price for copper.INTRODUCTIONTheoryThe application of electrochemically inert grinding media to mineral systems has been extensively studied (Table 1). Broadly, these studies indicate that most sulphide minerals are more noble than the grinding media used during comminution. Therefore, the sulphide minerals are cathodic with respect to the forged steel grinding media, and the following reactions apply:"

Jan 1, 2011

By Henri-Louis Jacob et Marc Bélanger

La province de Québec est un important producteur de roches et de minéraux industriels. En 1998, la valeur de cette production se chiffrait à 1,26 milliard de dollars canadiens (données préliminaires). Les minéraux industriels produits comprenaient: l'amiante extraite des gisements de chrysotile associés aux complexes ophiolitiques de Thetford Mines et d'Asbestos; l'ilménite et les scories enrichies en titane produites à partir du gisement d'ilménite massive du lac Tio associé au complexe anorthositique du lac Allard; le talc produit dans la région de Thetford Mines, à partir des roches à talc-carbonates associées à des feuillets de serpentinite; le mica broyé produit à partir de l'intrusion de suzorite du lac Letondal; le graphite en paillettes extrait du gisement du Lac-des-Îles; la wollastonite extraite d'une zone de skarn dans un lambeau de roches métasédimentaires enclavé dans le massif d'anor-thosite du LacSaint- Jean; le sel extrait aux Îles-de-la-Madeleine d'un gîte associé aux évaporites du Croupe de Windsor. Les nombreuses carrières dans le sud du Québec produisent, en plus de la pierre concassée, diverses substances incluant la pierre dimensionnelle (granite surtout); le calcaire pour la chaux, le ciment ainsi que divers usages industriels; la silice extraite à partir de formations de grès ou de quartzite. Le Québec est aussi un important producteur de tourbe de sphaignes qui est extraite de vastes tourbières qui se sont formées un peu partout dans le sud du Québec à la suite de la dernière glaciation. Les autres ressources en minéraux industriels comprennent des gîtes déjà exploités de brucite, de chromite, de magnésite dolomitique et de feldspaths ainsi que des gîtes de magnésite, de barytine et d'apatite faisant présentement l'objet d'évaluation.

Jan 1, 2001