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By James A. H. Church

This paper is in the nature of a protest against the dangerous propaganda afoot for the prevention of new mining undertakings and which is based on the imaginary 'blue ruin' conditions supposed to exist in the industry. An article by Mr. G. R. Pratt, A.M.E.I.C. in the first issue of the Western Canada News, February 2nd, 1925, and entitled "Review of Coal Mining in Alberta", is an excellent example of this type of propaganda. The article is a tissue of misstatements, faulty deductions and erroneous conclusions. For instance it contains the statement that some coal measures in Alberta are mined at great depth - whereas we all know that there is no coal mined at great depth anywhere in the province; another error is the classification of all mines under one head irrespective of whether they are mining prospects, 'country banks', or pukka mines equipped with railway facilities; and I believe that suppressio veri is tantamount to suggestio falsi. The bulk of his article hinges on a Table 1, which shows the details of coal produced in Alberta during 1923. Studying this table Mr. Pratt, in the manner of a conjurer producing rabbits from a hat, offers the following for the confusion of the public:- (1) "Waste effort, want of capital, waste of coal resources which result from unrestricted development"; the fact being that the waste is due to the failure of the Department of the Interior to exercise the powers which are inherent in the form of lease.

Jan 1, 1925

By T. P. Weldum, W. Conger

"These studies address the relationship between mill media sizing and its grinding efficiency. Starting with the results from a review of the literature, the issues of initial media sizing for a new ball milling circuit, and then optimal media sizing for an existing milling operation, were studied. The Functional Performance parameters “Mill Grinding Efficiency” and cumulative “Mill Grinding Rates” from both plant and test-scale equipment were used, and provide valuable new insight into this topic. A plant media sizing diagnostic tool is presented, as are newly developed testing equipment and evaluation methods, and recent case studies.REVIEW OF MEDIA SIZING LITERATURE For a plant metallurgist to answer the question “How can I maximize plant profit by manipulating this grinding circuit variable?” she must know what effect the variable has on grinding circuit efficiency. Despite the significant cost of grinding media and its potential effect on production capacity, the ‘best’ media sizing remains ill-defined for any given ball mill circuit in the industry today. The underlying reasons for this will be discussed. But the importance of this issue drove Metcom and its industrial partners to take on the challenge of how to engineer the ball charge for an existing grinding circuit. In the absence of any proven method, the first step was a review of the literature. Sponsored by Cleveland-Cliffs, Inc., a broad review of the literature was undertaken, producing “The Effect of Media Sizing on Ball Milling Efficiency” (McIvor, 1997). Among hundreds of publications that were reviewed that discuss the topics of media sizing or wear, forty-five were studied in detail. These were grouped into: plant experiences; laboratory and pilot plant investigations; media wear studies; population balance modeling studies; and general papers on ball milling which included the topic of media sizing. The reader is encouraged to refer to that review. The findings remain unchanged, although some relevant papers have been written since (e.g. Staples et al, 1997; Banasi et al, 1999; Orford et al, 2006; LaMarsh, 2015). The main findings of the review were as follows:"

Jan 1, 2018

By W. N. Hamilton

"Evaporites abound in the Western Canada sedimentary basin, recurring throughout the stratigraphic column and widely scattered over the basin region. Alberta, situated centrally over the basin, includes many of the evaporites within its borders, but only a few have the right geological conditions to form potential economic deposits of salt or gypsum. These include the Middle Devonian Elk Point Group and related evaporites, Upper Devonian Wabamun Group-Palliser Formation evaporites, and evaporites of the 'Triassic Charlie Lake and Whitehorse formations.Salt deposits underlie almost half of Alberta. The major deposits belong to the Elk Point Group, which includes thick salt units in the Lotsberg, Cold Lake and Prairie Evaporite formations. Another, younger salt deposit in the Wabamun Group has only local distribution. Elk Point salts have a maximum aggregate thickness of 430 m in east-central Alberta. The deposits deepen southwestward across the province, from minimum depths of210 m at Fort McMurray to 1820 m at Edmonton.The thickest, most extensive salt deposits are the upper Lotsberg and Prairie Evaporite salts. Both have excellent development potential. The upper Lotsberg is up to 150 m thick, consists of clear, very coarse crystalline halite with only minor impurities, and has a notable lack of non-salt strata in its succession. Analytical data for the Lotsberg Salt show extraordinary chemical purity. Prairie Evaporite Salt differs lithologically from the Lotsberg in having a significant non-salt component. The deposit is up to 200 m thick and consists of medium crystalline halite, brownish coloured and cloudy as a result of finely dispersed impurities. The main impurities-shale, anhydrite and dolomite-are most prevalent as interbeds in the salt succession, ranging from very thin laminae to beds several metres thick. Although of lesser purity, the Prairie Evaporite Salt is shallower, thicker and more extensive than the Lotsberg and the salt quality is quite acceptable for most industrial uses."

Jan 1, 1982

By Trang T. Tran-Valade

With continually increasing energy prices, the mining industry has been on the search for new energy optimization technologies. One area that is garnering great interest is Ventilation-On-Demand (VOD). Prior to selection and implementation of a VOD solution, it is important to fully understand the mine requirements as well as its existing infrastructure and the interaction with other automation in place at the site. With this information, a business case can be generated including a cost versus benefit comparison for various control strategies. To assist in the development of the business case, this paper will identify key areas for consideration and recommendations for an implementation plan.

May 1, 2013

By C. R. Kato, G. Proulx

"Within the continuous scenario of reduced aluminium price and plants production costs increase, the energy consumption optimization in the aluminum electrolytic pots continues as the main focus for the producers. Energy consumption was chosen as a key performance indicator to drive the efforts and actions for improvements. Alcoa improved the energy consumption by approximately 3% from 2005 to 2015. This improvement was a result of best practices implementation, new technologies introduction, strategic actions with plant curtailments and management practices. The main objective of this paper is to highlight the importance of the management practices for planning and operational improvements beyond the technology changes. About 10 years ago, Alcoa reorganized its approach to retain knowledge in the Smelters by using a Best Practices format. For each specific subject, a skilled team defined the minimum requirements and the Best Practices for several aspects of operation and maintenance, which affect the environment, safety, cost, customers and performance. These Best Practices were deployed to all Smelters combined with training sessions to process and operation professionals. We will describe how the Best Practices were organized, the deployment strategy used, and the approach to measure the plants’ success. We will describe the management approach that includes Manufacturing Analyses focused on 3-year potential, annual planning, and weekly monitoring of plant stability. A manufacturing analysis is organized at select plants with cross-functional participation of specialists from technical, operational, procurement and finance. The output of a manufacturing analysis includes a roadmap of enablers to improve energy efficiency. A quarterly follow-up of enabler deployment is held with the plant and resources that participated in the analysis. Annually, there is a Planning Process where energy consumption enablers are selected to be implemented during the next 3 years for each plant. A monthly critical analysis is made by the plants with regional best practice support. On a weekly basis, key performance indicators are reviewed with determination of a stability index for each plant. Any deviation signal of unstable condition is alerted and supporting resources are diverted to the plant to reverse trend with countermeasures.INTRODUCTIONDue to factors like excess aluminum in the market and lower consumption in China, the LME price is declining along the last years, as showed in Figure 1. In 2011, the price peaked at US$ 2,400/ton and since then, continues to trend down and approaching the lowest level at US$ 1,500/ton in the last 5 years."

Jan 1, 2016

This paper details a brief history of the Australian gold industry from the 1980s gold boom to the present day, highlighting an industry characterised by innovation in plant design and junior companies prepared to "have a go", in contrast to the conservatism of many larger mining companies. Design flexibility, the innovation of new processes, the preparedness to exchange "process know how" and technology singularly differentiated the gold industry from other sectors during the 1980s to the present. The introduction of two stage crushing, semi autogenous (SAG) milling, and pebble crushing, mill innovations, carbon in pulp (CIP) and carbon in leach (CIL) and the North Kalgoorlie screen etc were all exciting changes in the industry.

Jan 1, 2011

By T. Patching

"A GLANCE BACK AT what has happened in the past is often a useful guide to the future, although it should be used mainly to provide a sense of direction rather than a map that must be followed. As a preamble to discussing some of the questions posed by the organizing committee it may be appropriate to briefly review the distribution and careers of the graduates of our Department since the first degree in mining engineering was awarded in 1916. An attempt has been made to keep a record of the locations and careers of the Department's 540 graduates in mining and metallurgical engineering. Almost all of those who graduated before 1930 have now retired, but a very large proportion held positions as senior executives prior to retirement. A major proportion of those who graduated before 1950 are now in what might be considered senior management positions. Those who have 10 to 20 years of experience are generally in work of senior engineering responsibility or in supervisory or junior management ranks, while those who graduated in the last ten years appear to be generally in staff engineering or junior supervisory positions. This classification is admittedly imprecise because it is difficult to determine from a job description whether duties should be considered of an engineering or management nature - a distinction between the two terms is often over-emphasized. Nevertheless, the trend from technical engineering to management responsibilities with seniority and years of experience is clear in the careers that we have been able to follow."

Jan 1, 1972

By Link. Theo A.

Introduction Since the discovery of a major oil pool at Leduc, Alberta, on February 13th, 1947, the long spell of 'oil drought' in Western Canada is now being turned into an oil and gas flood which requires immediate action to obtain the optimum economic benefits. The Woodbend, Section 9, and Okalta extensions of the Leduc field itself have been established; the Redwater pool, lying thirty-seven miles northeast of Edmonton, has been discovered and is being drilled up, and the Imperial Schoepp No. 1 or Golden Spike discovery holds promise of something phenomenal in view of the 500 feet of oil-saturated coral-reef porosity whose areal extent is not known. Imperial Stanolind Barrhead No. 1, northwest of Edmonton, revealed the presence of oil in the Madison, and just recently Gulf N.J. Ellis No. 1, some sixty miles southeast of Leduc, found commercial production in the Leduc D-2 discovery zone. In addition to these Paloeozoic discoveries, gas and oil reserves have also been established in the Upper and Lower Cretaceous, which must be penetrated by all tests on the way through the geological column to the Devonian. If ever there appeared to be an index of 'things to come' in the oil industry, this is it. However, without these recent discoveries the picture in Western Canada does and always did, look very promising indeed. A brief survey of the geological setting in Western Canada is the object of this contribution.

Jan 1, 1949

By E. Rosseland

Glencore Nikkelverk is operating its Chlorine Leach Process in Kristiansand, Norway, producing nickel, copper and cobalt metals by electrowinning. The copper tankhouse, with an annual capacity of 40 000 tons, is based on traditional technology with copper starting sheets and cast lead anodes. Due to the integration of this copper sulphate process in a nickel chloride refinery, operating conditions are unique. In recent years, operating costs have escalated, and health, safety and environment are top priorities. Test work on a new copper process involving permanent cathodes was therefore initiated in 2007, and a pilot plant was started up in 2012. The objective was to introduce innovative technologies and tailor these to be robust in the Nikkelverk process, to form a basis for a new sustainable copper tankhouse with a high degree of automation. Key learnings from more than 10 years of R&D work is presented, focusing on cathode materials and copper metal deposition including product quality, robotic stripping, coated titanium anodes, electrode contacts and alignment, electrode current monitoring with Hatch HELM tracker technology and acid mist capture using cell hoods with off-gas scrubbing. The new copper tankhouse project was approved in December 2018, and commissioning is planned in 2022. INTRODUCTION The Kristiansand nickel refinery was started up in 1910, processing nickel-copper matte originating from Norwegian mines. It was the first industrial plant in the world to produce nickel by electrolysis using the Hybinette electrorefining process. After roasting to burn off sulphur in the matte, copper was leached and recovered as cathodes by electrowinning with lead anodes. In the first years, the copper cathodes were fire- refined and cast into ingots for sale (Thonstad Sandvik, 2004). The Nikkelverk refinery was acquired by Falconbridge Ltd. in 1929, and since then matte from Sudbury, Canada has been the main feed source. The Hybinette process was in operation until 1975 when conversion to the newly developed Chlorine Leach Process was started (Stensholt, Zachariasen, & Lund, 1986). In this process still used today, nickel and part of the copper in the matte is leached using chlorine gas generated on dimensionally stable anodes in the nickel and cobalt electrowinning tankhouses, as illustrated in Figure 1. The presence of dissolved copper ions in the strong chloride leach solution is essential for effective chlorine absorption and nickel dissolution. To improve copper-nickel separation, slurry from the atmospheric leach is pumped to autoclaves and then to cementation tanks for precipitation of copper as copper sulphide, which is collected in filter presses. The leach residue, also containing the precious metals, goes through a 3-stage wash to remove chlorides before being introduced as a slurry to fluid-bed roasters for sulphur removal. The resulting calcine is then leached in spent electrolyte from the copper electrowinning tankhouse, to dissolve most of the copper and also some nickel, cobalt and other elements. After separation of the leach residue, elements like Bi, Te, As and Ag are removed from the strong copper sulphate solution by reaction with metallic copper in three columns in series filled with cut copper cathodes. The purified solution then passes polishing filters before being mixed with spent electrolyte and returned to the electrowinning cells.

Jan 1, 2019

By Robert Hamilton

Aur Resources is Canada's leading copper mining company with producing mines and development projects in North, Central, and South America. Copper production from Louvicourt Mine in Quebec, Quebrada Blanca, and Andacollo Mines in Chile had a record of 245 million pounds in 2001. Located 600 km North of Montreal, Louvicourt Mine is a joint venture between Aur Resources (30%), Teck Cominco (45%), and Novicourt (45%). Aur Resources is the mine operator with 280 employees working to produce a copper and zinc concentrate. In operation since 1994, the mine has produced a total of 12,606,000 metric tonnes of ore grading 3.6 % Cu, 1.5 % Zn, 26gr./m.t Ag, 0.9gr.m.t Au. This highly mechanized mine reached full production in August 1995 at 4,000 tpd. From 1996 to 2001, the average mine production rate was more than 4,300 tpd. The Louvicourt Mine continued its record of solid performance in 2002 and is expected to continue to do so for the balance of its 2.5 years mine life.

May 1, 2003

By I. I. Inculet, M. A. Bergougnou, J. D. Brown, R. M. Quigley, D. K. Faurschou

"Coal from Hat Creek, B. C., has been successfully beneficiated to remove ash while retaining calorific value by a dry electrostatic separation process using a fluidized bed for triboelectrification. Two samples of Hat Creek coal used in the beneficiation experiments have been characterized particularly with respect to their mineral and clay content. The calorific value recovery exceeds the simple dry coal recovery because of the heat lost in altering the clay minerals of the ash fraction during burning. Recoveries and ash contents of the beneficiated coal are comparable to recoveries by water washing, but the dry process avoids the potential water pollution problems.IntroductionProposals have been made which suggest an interim Canadian coal production target for the end of the century which will require a four- to fivefold increase over the 1977 production. This implies a nominal annual growth rate of about 6070 to achieve a production rate of 115 to 140 million tonnes/year. Whether or not this target is realistic, it is becoming increasingly evident that coal must be utilized more fully on a world-wide basis. The crisis in Iran has provided the latest stimulus to renewed interest in Canadian coals for domestic use and export.The emerging new era of coal utilization for fuel and chemical feedstock will not, however, generally tolerate the level of coal technology which prevailed prior to the availability of abundant cheap oil and natural gas. Economic, environmental and resource management considerations will necessitate, for example, the use of improved methods of beneficiating coal. Continued development and application of conventional processes, principally aqueous, involving heavy media and cyclones will solve many of the problems. However, less conventional processes may be preferable or necessary in certain applications."

Jan 1, 1980

By William M. (Bill) Shaver

"The author will review the early history of shaft sinking as well as focus on the improvements made in shaft design and construction over the last fifty years (1970 to 2019) to predict how shaft sinking will change over the next fifty years and describe what the shaft sinking world might look like in 2070. INTRODUCTION It is a great honour to be one of your keynote speakers for the Fourth International Conference on Shaft Design and Construction being held in Toronto in November 2019. This is one of the opportunities we have to thank the Mining Companies of the world as well as the industries and companies we serve for their support of the mining contracting and shaft sinking business of Canada and the world at large. Many of these companies are represented here today. Without your support many of the innovations we will talk about today would not be possible. We would also like to thank all the companies that work with us in our business including all the contractors and suppliers who provide the various services we require. These include equipment manufacturers, engineering companies, project management companies and suppliers large and small who cater to our every need as quickly as possible. Without all these partners we would not be as good as we are. Many of these companies are our sponsors this week. Thank you from all of us! This is also an appropriate time to pause and think about those Shaft Sinkers we have lost and those who have been injured on our projects around the world. Please bow your head and remember the Shaft Sinkers you have worked with, who did not return home or those who returned home injured. Think about how we can continue the work of making shafts safer every day as we go forward with our projects so everyone goes home to their families safe and sound. Pause for a minute and thank you. The subject matter we have chosen to discuss today is “Shaft Sinking in the Next Five Decades”. How will the work be done, how fast will it be done, what will it cost, and why we think this may occur? It is appropriate to consider this over the next few days with this auspicious group we have assembled. Today, we will look back at all the advances that have been made over the last many years and look ahead to the future to attempt to predict what shaft sinking will look like in 2070. When I look around the room I recognize that many of us will not be around then so we need not worry about being wrong. Suffice it to say that the next 50 years will be very interesting and exciting for the shaft sinking business."

Jan 1, 2019

By Fan Delian, Ye Jie, Lui Tiebing

The lower and the upper parts of the Doushantuo Fonnation, Hubei Province, China, contain silicate-type K-rich beds (illite and feldspar), and intraclastic phosphorites, as well as Ag-V and V deposits in a "Black Shale Series". The K-rich beds fonned in an anoxic basin whereas the phosphorites fonned in a more oxic and higher energy depositional environment. The Black Shale Series occurs in the lower and upper parts of the Doushantuo Fonnation; that in the upper part consists of black illite shale and dark gray dolostone, and contains Se-rich Ag and V deposits. These deposits are of more industrial significance than the previously discovered Ni-Mo polyelement sulfide deposits which occur in the Lower Cambrian Black Shales Series of South China. Studies of lithotype, sedimentary sequence, and geochemistry of the Doushantuo Fonnation have led to more attention being focused on the uppennost Black Shale Series and its Ag-V and V deposits. There are three ore types: black, Ag-V-rich, illite shale; black, V-rich, illite shale; and dark gray, Ag-Vrich, fmely crystalline dolostone. The first two ore types contain 3070 to 5% Corg and the last, 1.25%. The Ag-bearing minerals are naumannite, argyrodite, aguilarite, acanthite, and native silver that occur as inclusions in pyrite associated with barite. Vanadium substitutes for AI in illite and is also related to organic-matter contents. Because (1) the pre-Sinian Kongling Group contains one to three times greater than the Clark Ag value; (2) black, illite shale has a negative Ce anomaly; and (3) there are large occurrences of black, K-rich, tuffaceous, fme siltstone, the sources of Ag are thought to include subaerial and submarine volcanic materials. It is proposed that Ag, V, and Se were absorbed by clay particles and organic matter during syngenetic deposition in an anoxic environment; Ag subsequently was reconcentrated into sulfides and selenides, whereas V was incorporated structurally into illite during early and late diagenesis. These types of Black Shale Series-hosted Ag-V and V deposits are, therefore, considered to be sedimentary-diagenetic in origin.

Jan 1, 1992

By L. Jones, S. R. Lawrence, A. R. Holloway

Whilst dense medium separation is best known for its ability to concentrate diamond and coal deposits, the process is now being employed in southern Africa as a pre-concentration step to improve the economics of platinum group metal and nickel ores. DMS plants built for these industries (such as the 1600tph unit at Tati Nickel, Botswana), are spearheading an expansion in this area by reducing mine and process operating costs yet maintaining economic metal recoveries. This paper provides an overview of DMS technology and examines the economic benefits available to North American operators and projects, with recent case studies as reference.

Jan 1, 2009

By G. Barrasso

REACH was proposed by the EU Commission in October 2003 and stands for the Registration Evaluation, Authorisation and Restriction of Chemicals. It requires that all substances identified as persistent, bio-accumulative and toxic, whether the risk of those chemicals being released is real or perceived, require registration prior to them being allowed to be imported into the European Union. An internal investigation by the metals industry indicates that almost all primary raw materials streams would be classified as hazardous due to the potential health or environmental hazard properties of one or more of their ingredients. REACH uses a wide definition for chemicals and metals and as such its implications greatly impact the entire supply chain of the metals industry. The process of registration would require the producer/ importer to produce a dossier. Initiatives along the same lines as the EU REACH are also coming up in other parts of the world. REACH requires registration of at least four substances manufactured by the aluminium industry: aluminium metal, including powder, aluminium oxide, and aluminium hydroxide. The proposed legislation permits the affected companies to band together to form a consortium to develop certain aspects of the registration application. The aluminium industry has established a consortium and testing is currently underway.

Jan 1, 2006

By J. E. Hawley

"The Aldermac copper deposit is in Beauchastel township, Abitibi county, Quebec. It lies about 11 miles west of Noranda. It has been described by Cooke, James, and Mawdsley(2) and by Bruce(3) and has been mapped in detail by W. Samuel and the late K. W. Fritzsche, former Mine Geologist, and by J . E. Gill and A. R. Byers, so that most of the particulars contained in the description that follows are largely the result of the work of others than the writer, whose connection with the deposit, in a consulting capacity, extended over the last 5 years of the life of the mine.According to A. V. Corlett, former Mine Manager, the property was staked during the early winter months of 1923 because of its location adjacent to the syenite intrusive that had been mapped by Cooke near the height-of-land in this township. An examination by Mr. Corlett in 1924 revealed mineralized zones to the north of MacKay lake, and in the vicinity of these K. W. Fritzsche, by dip needle and trenching, discovered the No. 1 and No. 2 deposits, which were both too small and too low grade for exploitation. During the winter of 1925, A. A. MacKay, with a dip needle, picked up a magnetic 'anomaly' in a drift-covered area about 600 feet to the north of previous workings. Trenching here revealed only a narrow zone of mineralization of little consequence, but, farther east, MacKay discovered a more pronounced 'anomaly' over what later drilling and underground work proved to be ore of commercial grade (No. 3 and No. 4 orebodies)."

Jan 1, 1954

By Jehan Rondot, Raymond Marleau

"Des quartzites trés pars ont été découverts au cours de la cartographie de la region du lac des Martres, étape de l'étude géologique de la region de Charlevoix.On distingue quatre groupes métasédimentaires, tons con tenant des niveaux de quartzite dans an mains deux domaines géologique différents, c'est à l'ouest, clans le do¬maine gneisso-charnockitique que se situent les quartzites du groupe des Martres. Quartzite et gneiss à, grenat et sillimanite, en banes épais, constituent la formation de La Galette. A Pest, dans un environnement gneisso-granitique, les deux groupes métasédimentaires de Saint-Siméon, et de La Malbaie comprennent, par contraste, des bancs pen épais et de compositions variées. Les niveaux de quartzite dépassent rarement 50 m d'épaisseur. L'autre groupe métasédimentaires, celui de Saint-Tite des Caps, recoupé de nombreuses intrusions charnockitiques et granitiques, ne possède que de minces niveaux de quartzite.La pureté et la grande épaisseur des quartzites de La Galette suppose une histoire complexe qui se termine par des depots continentaux de climat aride, par opposition aux depots marins des autres groupes. D'autre part, la presence de ces quartzites an sein de roches Presque anhy¬dres et de haute temperature que sont les charnockites leur confére des caractéristiques de fusion sans decrepitation.Parmi la multitude de depots de quartzite qui existe clans le monde, peu sont de qualité supérieure. Or, de par sa composition chimique, le quartzite de La Galette se compare avantageusement à ceux des meilleurs gisements des Etats-Unis, de l'Europe de l'Ouest et de l'Afrique du Sud. D'accès facile pour l'exploitation, les gisements ne sont qu'à une trentaine de milles de Baie Saint-Paul ou de La Malbaie, sur le Saint-Laurent.L'utilisation en metallurgic prévue pour le quartzite de La Galette comprend la production de silicium, de ferro¬silicium et d'autres alliages de silicium. La composition du quartzite est en outre appropriée pour la production de carbure de silicium et de silicate de sodium. Les fines peuvent être utilisées pour la fabrication du verre et comme matiere de charge"

Jan 1, 1977

By Marcio Luis S. Godoy

The Salobo Project will be the first Vale operation to use an HPGR mill to process copper-gold ore. The mine is located in Para state, southeast of the Amazon region in Brazil. The circuit was designed to treat 12 million metric tons per year of finely disseminated sulphide ore with high hardness. The comminution circuit comprises a gyratory primary crusher, secondary crushing utilizing two cone crushers, two 2 x 1.5 m HPGR operating in closed configuration with 6 mm screens, followed by two 26 x 40 ft ball mills. The concentration circuit consists of two rougher flotation stages using mechanical cells, regrinding with vertical mills, three cleaner stages with columns and one cleaner scavenger stage in mechanical cells. The concentrate is dewatered, filtered and transported by trucks and train to the port, to be exported. The circuit was designed on the basis of data obtained from a comprehensive laboratory and pilot plant campaign. The ore variability was assessed through simulation using data from a drilling core characterization program. The start-up of the industrial plant is planned for 2011. This paper describes the main aspects of circuit design, as well as information related to the beginning of the project construction.

May 1, 2010

By J. E. Gill

Introduction During the past summer, detailed geological mapping was extended to cover the entire group of 31 claims owned by Waite-Ackerman-Montgomery Mines, Ltd., and considerable new information was revealed by development and exploratory work underground. These new facts provide a more complete view of the lithology and structure of the area than has heretofore been available. They also necessitate revision of certain interpretations presented last year by Peale (l), and have served to straighten out some of the problems suggested by Porritt (2). The purpose of this paper is to outline in a broad way the relations as now understood and to discuss in detail certain points which should be of interest to members of the Institute. Maps and records by the mine staff have been freely used in arriving at the interpretation presented in the following pages. The writers are especially indebted to Mr. R. V. Porritt, the mine manager, with whom many of the problems touched upon were discussed on the ground and whose intimate knowledge of the geology of the underground workings aided greatly in testing various hypotheses. The writers have profited greatly, also, from close association with Dr. W. F. James during the course of the work. Permission to publish the included data has very kindly been given .by the management.

Jan 1, 1932

By S. Espley, G. Tan

"Inco's Little Stobie Mine is a low-grade nickel operation producing approximately 4()()() tons per day. Backfill has never been an economical option at the mine; therefore, the only viable type of mining in the upper zones has been by sub-level cave. This mining method allows for the draw-down of a rock cover into the empty stopes to provide stability to the over-all rock mass. In the lower areas of the mine, bulk blasthole mining methods have taken place, without rock fill, resulting in extremely large open stopes. As the mine reaches its final stage of recovery, it is inevitable that the hangingwall of the large voids will undergo tensile failure via spoiling.This paper deals with the collaborating efforts of Inco's Rock Mechanics group and the Little Stobie mining operations toward the successful recovery of the ore zone remnants such that the inevitable failure, and time of failure, of the rock mass is ""controlled"". Within the mining scheme, several key requirements had to be met to satisfy the operations: (1) production rates; (2) good blast fragmentation; and (3) secure pulling-horizons. A full-scale rock mechanics study was carried out involving: numerical modelling studies; pulling ellipse analyses; blast design, monitoring and analyses; laser profiling; and time domain rej7ectometry (TDR) instrumentation. The final recovery scheme, employing a controlled failure, involves recommendations on: (1) blasting techniques; (2) support systems; (3) mining sequences and scenarios; and (4) monitoring systems."

Jan 1, 1994