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By Lawrence D. Meinert

Abstract-Most large skarn deposits are zoned in both space and time relative to associated intrusions. Zonation occurs on scales from kilometers to micrometers, and reflects infiltrative fluid flow, wallrock reaction, temperature variations, and fluid mixing. The most spectacular examples of skarn zonation usually occur at the skarn-marble contact, where transitions between monomineralic bands can be knife sharp. Other small-scale examples occur in zoned veins and individual mineral crystals. Although, visually striking and scientifically interesting, in mineral exploration these small-scale variations are less useful than deposit- or district-scale zonation. In most skarn systems there is a general zonation pattern of proximal garnet, distal pyroxene, and vesuvianite (or a pyroxenoid such as wollastonite, bustamite, or rhodonite) at the marble front. As well, individual skarn minerals may display systematic color or compositional variations within the larger zonation pattern. Such patterns are reviewed for 14 well-studied examples of Cu, W, Sn, Au, and Zn-Pb skarns. In addition, many deposits have endoskarn or other alteration of the associated intrusion, and recrystallization or other subtle changes have occurred in the surrounding wallrocks. Copper skarns, such as Mines Gaspé in Quebec and Big Gossan in Irian Jaya, have high ratios of garnet:pyroxene and are zoned outward from the intrusion, to garnet, to pyroxene, to massive-sulfide replacement and vein deposits. Garnets in Cu skarn are Fe-rich and change from dark red-brown near the intrusive contact to paler brown, green, or yellow in distal locations. Pyroxenes in Cu skarns are pale and diopsidic near the intrusion, and become darker and more Fe- and Mn-rich away from the intrusion. Tungsten skarns, such as Salau and Costabonne in France and Pine Creek and Garnet Dike in California, have intermediate ratios of garnet:pyroxene, are more extensive vertically and along strike than perpendicular to the intrusive contact, and have zonation patterns commonly complicated by overprinting of metamorphic lithologies. In W skarns, garnet is commonly subcalcic and the pyroxene is Fe-rich, reflecting particularly reducing wallrocks or great depth of formation. Tin skarns, such as Dachang in China and Moina in Australia, also can have subcalcic garnet and Fe-rich pyroxene, but this reduced mineral assemblage typically is due to an association with reduced S-type granites. Tin skarns differ from most other skarn types in having a late greisen stage that may replace earlier Sn-bearing calc-silicate minerals, thus liberating Sn to form cassiterite. Many high-grade Au skarns, such as Hedley in British Columbia and Fortitude in Nevada, have low ratios of garnet:pyroxene and are associated both with reduced plutons and reduced wallrocks. Goldrich zones occur in Fe-rich, pyroxene-dominant, distal skarn. Zn-Pb skarns, such as the Yeonhwa- Ulchin district in Korea and Groundhog in New Mexico, have low ratios of garnet:pyroxene and generally form distal to associated intrusions. These skarns also are zoned from proximal garnet to distal pyroxene and pyroxenoid (bustamite-rhodonite), with significant zones of massive sulfides within and beyond skarn. Manganese enrichment of most mineral phases, particularly pyroxene, is characteristic of distal zones. Fundamental controls on skarn zonation include temperature, depth of formation, composition and oxidation state of associated plutons and wallrocks, and tectonic setting. Most W skarns form at relatively great depth, 5 km to 20 km, with extensive high-temperature metamorphic and metasomatic mineral assemblages. In contrast, most other skarn types are relatively shallow, <10 km and mostly <5 km, with limited, lower temperature metamorphic aureoles. Differences in oxidation state correlate well with different skarn zonation patterns, particularly garnet:pyroxene ratios and compositions, and can be used in both classification of and exploration for s

Jan 1, 1997

By Humphrey Dean

"Canadian mining companies now operate numerous Koepe-type friction hoists in a variety of different shafts, most of which have a depth in excess of 3,000 feet. Rope performance reliability is an absolutely essential ingredient of most installations and, for this to be provided, a more comprehensive understanding of rope reactions to applied stresses is required.It is the intent of this paper to illustrate for the operators the importance of the critical stresses encountered and to provide a maintenance program designed to circumvent potential difficulties."

Jan 1, 1970

1.Assessment of methane content in coal. Given a naturally low methane content in 11 Coal Seam and the fact that the areas of the 11 Seam adjacent to the tunnelway were degassing for a very, very long time due to previous development and mining, it is conservatively estimated that the remaining in -situ methane is less than 0.5m3/tonne. 2. Continuous miner cutting rate based on the past practice. The best loading rate recorded at the past operations of Smoky River Coal was 45 seconds for a 8 tonnes shuttle car. Using these records, the maximum peak loading rate potential at the face is calculated at 0.178 tonnes per one second or 10.67 tonnes per one minute. 3. Methane release at the face. ?The actual face methane liberation, conservatively assumed at 40% of the total in situ content: 0.20 m3/tonne ?The peak cutting rate: 0.178 t/sec ?The maximum (peak) face methane release: 0.20*0.178 = 0.036 m3/sec

May 1, 2003

By L. E. Djingheuzian

"IntroductionIN 1940, in a series of articles, M. W. von Bernewitz(l) reviewed in detail roasting of gold and silver sulphide ores and concentrates. Since that time some significant developments in roasting have taken place, and a number of papers have appeared in the Canadian technical literature, dealing severally with the roasting of a particular ore or concentrate.The purpose of this paper is not only to review some of these Canadian papers and bring the information on Canadian roasting practices to .date, but also to analyse the mechanism of roasting. Hence, it is proposed to start with a study of physico-cl1emical factors fundamental in roasting, the knowledge of which, by creating a sound basis for a proper roaster design, makes good roasting possible.Physico-Chemical FactorsRoasting can be defined as heating sulphide ores in presence of air below fusion points of the constituent minerals, at such temperatures as to convert metallic sulphides to oxides. Hence, roasting is a chemical process.The object of roasting is, by changing, chemically, mineral constituents of sulphide ores, to make the economic recovery of the desired •Constituent metal by a subsequent standard treatment possible. For instance, pyritic ores, containing gold in sub-microscopic form which no amount of grinding would release, are roasted in order, by oxidizing the sulphides, to open up their structures to such an extent as to enable cyanide solutions to come into contact with the gold and dissolve it. The production of porous calcine is, therefore, the object of roasting of refractory auriferous sulphide ores or concentrates. Such a porous calcine may be defined as a desirable calcine, and the roasts which produce desirable calcines can in their turn be termed desirable roasts."

Jan 1, 1952

By L. H. Michaud

"Albian Sands Energy (ASE), an oil sands surface mining and extraction operation, is currently undergoing start-up and is scheduled to ramp-up to full production by mid-2003. Startup includes the selection and implementation of over 75 IT systems or computer applications which include: engineering applications; systems required to control mining activities, maintenance, the processing plant and utilities; and also systems required to run the company, such as human resources, finances and inventory/ warehousing.This paper outlines the processes used for the selection, implementation and integration of these systems in order to optimize the use of information and to meet the technical, business and IT requirements of the company. The first step in ASE’s approach to identifying system requirements is the development of a business activity model, outlining all tasks involved in running the operations. The computer applications required to accomplish each task are then identified by having the IT team work closely with each technical and business unit. Historically, at some companies, the selection of systems has been led by the IT team or by consultants, with little input from the technical or business units. Typically, this results in products that do not meet the company’s expectations. To ensure a more positive outcome, ASE believes that it is imperative that the company’s technical and business people be closely involved in the selection process.Integration of the IT systems is also key, including linking all applications through a data warehouse and EDMS. Over 120 required integrations have been identified. This ensures the storage of all data in only one location, data security, and easy data and document retrieval for all requirements throughout the company"

Jan 1, 2003

By J. Lazareck

"XPotential Products Inc. has developed technologies to convert auto shredder residues and other forms of plastic waste into useful products such as posts suitable for retaining walls and parking curbs. The technology is competitive provided low-cost plastic waste is available, and could have applications throughout the world. The paper describes the technology used and illustrates the various processing steps. Development of the TechnologyPresently, state-of-the-art auto shredding yields approximately 75% ferrous and non-ferrous metals and approximately 25% by weight of auto shredder residue (ASR). Advances in metal shredding and non-ferrous metal separation technologies turned XPotential Products Inc.’s attention to ASR as a potential revenue source, or at least a means to markedly reduce the cost of disposal. This abundance of nuisance ASR was, in the company’s view, a potential resource as derelict autos and white goods were similarly perceived 40 years ago. As owners of General Scrap & Car Shredder Ltd. in western Canada, XPotential faced significant disposal costs for four shredders. This journey began over 10 years ago and took many twists and turns until a final course of action was chosen. The recovery of the metallic portion of vehicles and white goods has reached technological maturity and attempts to add value are now achievable only in very small increments."

Jan 1, 2004

By Wayne D. Goodfellow, William M. Luff, Steven J. Juras

Abstract-Brunswick No. 12 is a vent-proximal massive sulfide deposit that formed above a feeder pipe with associated hydrothermal alteration. Because of the replacement of bedded sulfides deposited above the hydrothermal vent, individual sulfide lenses show the following vertical and lateral zoning outward from the vent complex: massive pyrite-pyrrhotite-chalcopyrite core - interlayered pyrite-sphalerite-galena (Pb-Zn ore zone) - bedded pyrite. The feeder zone which underlies the Cu-rich core consists of an anastomosing network of pyrite-pyrrhotite-chalcopyrite­ quartz veins with variable and generally minor contents of ferroan carbonate, Fe-rich chlorite, sphalerite, galena and arsenopyrite. Hydrothermal alteration of felsic igneous rocks hosting and adjacent to the feeder pipe is represented by an inner zone (zone 1) characterized by sulfide stringers, Fe-rich chlorite, muscovite, quartz, and ferroan carbonate that formed at the expense of feldspars and what was probably glass; outer zones (Il and III) are represented by Mg-rich chlorite and muscovite formation, and the albitization and silicification of K-feldspar. Accompanying these alteration trends is a marked decrease of Na + Ca, and an increase in Fe + Mg + C03 in zone 1, and increases in Mg + Na in the outer zones. The classic zoning of metals within the sulfide lenses, the formation of a feeder pipe below the vent-proximal sulfide core, and the hydrothermal alteration of felsic volcanic rocks cut by the feeder pipe all support a vent-proximal origin for the Brunswick No. 12 deposit. Furthermore, restriction of sulfide stringer mineralization to the footwall sequence, the folding of the stringer zone by an F1 fold, and the difficulty of long distance mass transfer of metals from the sulfides into the host rocks all argue against a tectonic origin for the stringer zone. All of the evidence indicates that the feeder pipe formed during the ore forming hydrothermal event, but has been distorted and in some areas detached from the overlying massive sulfides during subsequent deformation.

Jan 1, 1992

By H. W. Smith, C. L. Lewis

"A process control computer has been installed in the Lake Dufault concentrator to: (a) control the on-stream X-ray analyzer and convert chart readings to elemental percentages, (b) calculate the flow rates required for the most important flotation reagents, using the amount of material entering the process, the analyses and the slurry pH, and (c) set the reagent feeder to these flow rates automatically. Although this project was largely experimental, to gain knowledge and experience in flotation process control, the objectives have been met and fully automatic computer control is now the normal mode of mill operation.This paper describes project planning and defines the system with respect to both control design and functional design. System operation -as seen by the mill operator -is detailed. Implementation of the system is described and the system is discussed in terms of its success, economic justification and future plans."

Jan 1, 1969

By Stephan I. Zajac, Roger A. Blais, John B. Stubbins

THE iron deposits of central Labrador occur within a relatively small area, herein called the Knob Lake Iron Range, in which a northwest-trending series of low hills and ridges defines the height-of-land at the boundary between provinces of Quebec and Newfound-land. Approximately two-thirds of the deposits are in Quebec and the remainder in Labrador, with several deposits straddling the inter-provincial boundary. These deposits are being exploited in open-pit mines by the Iron Ore Company of Canada centered at Schefferville, Quebec. Since 1954 this company has produced more than 56 million tons of iron ore to become Canada's leading iron ore producer. With indicated reserves of more than 375 million tons of direct-shipping ore and large tonnages of iron formation amenable to beneficiation, this mining district is assured of a long life. This paper describes the Knob Lake iron ores and their geological settings and stresses the features that lead to a better understanding of their origin. The

Jan 1, 1961

By M. Vallée, J. -P. Charette, D. P. Gold

"The Oka Carbonatite and Alkaline Complex is a Lower Cretaceous intrusive body of the Monteregian petrographic province. Carbonate rocks of various types, and associated alkaline rocks of the ijolite and okaite suites, are distributed in a double ring-dyke structure 4 Yi miles long by 1 1/2 miles across. Alnoite and alrioite breccia pipes intrude all rocks of the Complex and indicate, from inclusions, that a cover of Palaeozoic rocks existed at the time of emplacement.The results of radiometric, magnetic and gravity surveys of the Complex are compiled and discussed both with respect to the regional pattern and, locally, the bed-rock geology. The Complex is characterized by high-intensity anomalies.Exploration activities started during 1953, and mining operations began in 1961 on the property of St. Lawrence Columbium and Metals Corporation, at one time the world's largest producer of niobium concentrates. Because of the boudinaged and fractured nature of many of the rocks and the variability in grade of the ore minerals, the role of the mining geologist is both demanding and exacting. Rock types are varied and their mutual relation-ships ambiguous, the minerals are rare and complex, and close geological control of the ore is needed in the mine and in the mill. Closely spaced diamond drill holes are needed for mining control, and the ore-waste contact is defined mainly by assay results.In the exploration for 'carbonatites' in Eastern Canada, aeromagnetic surveys are judged to be the best exploration tool, followed in decreasing order by the search for circular structures on aerial photographs, regional gravity surveys and radiometric surveys."

Jan 1, 1967

By G. E. Viens, R. A. Campbell, G. N. Banks

A survey of the literature reveals wide differences in the procedures used in making iron ore pellets and in the properties of the pellets obtained. In this paper, the methods of production and the properties of pellets, as reported in the literature, are examined in an effort to determine what correlations exist between them. An attempt is also made to determine the levels of the properties of pellets which are considered acceptable and desirable in modern practice. M UCH has been written regarding the important changes which have been taking place recently in the iron ore industry. As the demand for ore has increased and the supply of direct-shipping ore has dwindled, tl1e problems associated with the utilization of lower grade ores ha\•e been intensely investigated and important advances in both beneficiation and agglomeration techniques have taken place. In particular, there has been a great deal of activity in connection with the pelletizing method of agglomeration. The superiority of pellets over raw ore has been demonstrated in blast furnace tests

Jan 1, 1962

By S Grönstrand, C. Perez, A. B. Yañez, F. Coddou, P. Morales, H. Elgueta

"The TankCell® 300 forced air flotation cell designed and built by Outotec, with active volume of over 300 m3, was installed at Codelco’s Chuquicamata concentrator in September 2008. After that, a program was conducted, where the new cell was tested against the plant’s existing flotation cells of type TankCell® 160, with an active volume of over 160 cubic meters.Testing program was exhaustive and detailed. Grade-recovery curves for each setup were reported, along with recoveries by particle size. Secondly, operational characteristics like air feed and froth height setpoints, and power consumption are compared side-by-side. As the third topic, gas dispersion characterization included velocity mapping, holdup, bubble size and bubble surface area flux operating range. The fourth area of interest was the retention time distribution (RTD) of the 300 and 160 m3 cells in comparison. A detailed campaign using radioactive tracer tests was conducted to clarify this.All of the investigations mentioned above are reported in separate papers for more detail. The aim of this paper is to collect the key findings, and present them in real terms, always referring to operability and metallurgy of the cells. It is destined for people designing new plants and to those improving and expanding existing ones. The most frequently heard question is: will the new large cells operate at same efficiency as the smaller ones. In short, the answer is: NO. They operate at improved efficiency!INTRODUCTIONIn the last two decades of minerals processing, there have been three dominant trends of development in the flotation technology: equipment scale-up, cell characterization and circuit modeling. Equipment scale-up has been rapid in the past two decades. In the year 1990, the largest flotation cell in use was 50 cubic meters of size. This year, 300 cubic meters is the largest installed cell. Characterization of flotation equipment and circuits is a very popular subject nowadays and has helped many operations to improve their recoveries through better control strategies, for example by using optimized air feed and level control profiles (Gorain, 2005), (Doucet, Gomez, Finch, 2006), or through better maintenance (Coleman, Urtubia, Alexander, 2006). Characterization work is closely linked to circuit modeling. The aim is to produce sufficient amount of data to allow reliable model building. These models are then used to design new circuits and to improve existing ones. So in summary, these three lines of development have slightly different aims – from capital and operational cost to performance optimization. Ultimately, they converge in the same end result – maximizing the profitability of the operation. Following chapters will summarize the extensive test work and scientific studies at Codelco Chuquicamata. The aim was to compare a TankCell® 300 cell, with nominal volume of 300 m3, against two TankCell® 160 machines, with 160 m3 volume in each. The work should yield answers to questions: does the larger cell produce similar results – is the scale-up successful?"

Jan 1, 2010

By A. Roy MacLean

"Cape Breton is an island on the eastern extremity of Nova Scotia, Canada. Here, coal mining under the Atlantic Ocean has been a way of life since the early French militia mined coal for heating purposes in 1720. Despite many ups and downs over the intervening years, the coal industry has survived and is now in a favourable position to benefit from the upswing in international coal usage.Mining in Cape Breton Early mining in Cape Breton was done by hand picks and shovels. The coal was loaded into mine cars which were hauled by horses to the main haulage system for transport to surface. Later, compressed-air cutting machines and drills led to the use of explosives to blast the coal so that it could be loaded by hand and transported as above. In 1923, longwall mining (by hand) was introduced. In 1950, the Dominion Coal Company developed the Dosco continuous miner in order to mechanize the longwall coal-getting operation. At this time, conveyor belts came into wide-spread use, along with diesel locomotives to haul mine cars from the longwall face to the main transport system. During this period, coal was also mined by conventional mechanized room-and-pillar equipment such as cutting machines, loaders, roof bolters, etc. This system evolved into the use of the continuous ·miners of today, which are employed in the Lingan Mine room-and-pillar section. However, this method is only satisfactory at shallow depths and gradients. For these reasons, almost all the coal in this coal field will be mined by longwall methods. In 1968, the Government of Canada expropriated the assets of the Dominion Coal Company on Cape Breton Island in order to prevent complete closure of an uneconomic industry by its owners. The government created, by an Act of Parliament, the Cape Breton Development Corporation which now operates the coal mines, coal preparation plants, railway, shipping pier and ancillary services (Fig. 2). Since its inception, the Corporation has closed three mines, opened two new mines, is in the process of developing a third new mine, and has invested heavily in the one mine which remains from its previous owners."

Jan 1, 1985

By Eugene (Gene) Bounds

The Mining industry faces many challenges, one of which is the demand to communicate over a variety of media, be it visual, sound, voice, data or any combination. Over the years multiple infrastructures have been put in place to overcome environmental obstacles and address these communication needs. A mine is an aggressive environment for electronic equipment and as such only the best quality equipment can perform under those special conditions of e.g. temperature, dust and humidity. Siemens Canada and its partner LComm will discuss a mining solution using a unique combination of technologies based on fibre optics, standard communication interfaces, passive antenna infrastructure and wireless services. The presentation looks at maximizing the use of infrastructure, reducing costs, addressing difficulty of communications coverage above and below the surface and the capability to future proof the capital investment as new requirements and applications are identified. Discussion will address: Wireless voice, high speed data Data acquisition for process control from sensors Video for remote control and security Miner safety and location Timely receipt of large volumes of information

Apr 1, 2005

"IntroductionThe Chairman, in his speech to this body last year in Montreal, stated that the Dominion Coal Board looked to and depended upon the Bureau of Statistics for statistical material, and the Bureau does collect and publish monthly and annual data on coal. It may therefore be asked why an officer of the Dominion Coal Board should prepare and give a talk on statistics.I would explain that it has been our experience in the Board that, since the supply and consumption of coal in Canada is subject to a seasonal ebb and flow, it can be more profitably studied on the basis of a twelve-month period ending on March 31st than of a calendar year, since the end of March does represent a fairly stable end point in this ebb and flow. The figures are not prepared or published by the Bureau on that basis and it has therefore been thought that a presentation on this fiscal-year period would be of interest. The Bureau of Statistics has agreed that this may be valuable and all the data here presented are based on the reports secured from various sources by the Mining, Metallurgical and Chemical Division, Dominion Bureau of Statistics. The only contribution by either myself or the staff of the Dominion Coal Board has been the tabulation in a different twelve month period, and the comments upon the picture presented.It should be noted that the data for the month of March, 1950, are not available in all cases and consequently the figures for that year contain an estimate for this month."

Jan 1, 1950

By Rowena Anderson

Mining companies are now looking for more effective ways to engage the community in public participation. Consensus-based approaches are becoming the most popularly applied way of achieving meaningful public participation. This paper introduces the principles surrounding consensus-building approaches and the processes for getting them started. The Healthy Communities Movement is one such consensus-based approach that offers a well-established holistic model for conceptualizing a healthy sustainable community. It also highlights the importance of public participation as an essential component of achieving a sustainable community. The paper concludes by illustrating how current company-community relations programs can utilize these models.

May 1, 2002

By L. H. Shang

The 319 Al-Si alloy is one of the most prominently used aluminium-based alloys in motor vehicle and engine applications, Microporosity present in 319 alloy castings reduces the load bearing capacity of the castings, The quantitative prediction of microporosity levels in Al-Si castings has been a subject of much interest for several years. In this research a new criteria function, tf 1,98 R13° (tf: local solidification time, R: cooling rate) was developed by multiple regression analyses, correlating thermal data from simulation studies to experimentally obtained microporosity values. This new criteria function gives a general prediction of microporosity in 319 Al-Si castings.

Jan 1, 2005

Mining Subscribes to Murphy?s Law Personal observations on the past ?Perfect, benign deposit mines can be screwed up-spills and concentrate handling issues ?Long term contamination and water management assessments inadequate ?The ?permitting mentality? and its effects on the application of proponent and regulator resources ?Reliance on simple principles but nature and chemistry is more complex

May 1, 2010

By D. Verhulst

The Altair process digests ilmenite concentrate in high-chloride HC1 solution, with complete dissolution of titanium and iron. The Fe(III) ions are reduced to the ferrous form, and the solution is cooled to produce crystalline ferrous chloride. Titanium is transferred by solvent extraction into a purified, concentrated Ti stream, which is spray-hydrolyzed to produce TiO2 hydrate. The hydrate is further calcined with additives to generate a high-quality pigment. All the chloride streams are recycled. In the original flowsheet, the iron chloride is pyrohydrolyzed by spray roasting to regenerate 18% HCl, which is subsequently converted to HC1 gas and water by pressure-swing distillation. A modified flowsheet includes an alternative to iron chloride spray roasting, producing more concentrated HCl and decreasing the amount of solution to be distilled. Improvements in digestion, solvent extraction and final pigment production are also introduced. A 100 t/y pilot plant is being built and will test the new concepts and confirm the overall water, acid and impurity balances of the process.

Jan 1, 2006

By Jack G. Hazan

The Critical Path Method is the modern scientific answer for solving the planning and scheduling problems inherent in today&apos;s complex projects. With this method, nothing is left to chance. All resources are controlled and kept to the minimum. The various phases are properly planned and strategically determined. Optimum conditions are evaluated for the most economical and fastest way to complete a definite project. The method must be fully understood and implemented with positive data and continuous feedback to obtain the best results. This paper covers the various aspects of the Critical Path Method and mentions some of its applications in the mining and metallurgical fields. T 0 progress to a higher state of human welfare necessarily involves sacrifices. The greatest sacrifice is to relinquish social freedom in favour of economic freedom. In the old days, for example, a cobbler was free to work at whatever time of the day he chose; today, he can&apos;t. He is now forced to adapt himself to environment and to work at stand-

Jan 1, 1965