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"Successive seismic waves may cause progressive weakening of a fault zone, which has been recognized as the mechanism of earthquake aftershocks. However, it is unclear that how a fault zone slips under each wave cycle and how slip displacement accumulates under continuous wave cycles. This laboratory study provides direct evidences on the slip process of a simulated granular fault zone dynamically induced by an incident wave without the effects of late-arriving and reflected waves. The experimental observations show forward and backward slip paths of the fault zone and partially recovered slip displacement after a wave incidence. The unrecovered slip displacement after each wave cycle can be accumulated until it reaches a critical slip distance for seismic faulting, which may reinterpret delayed triggering in earthquake dynamics. The limited interseismic period restricts fault self-healing in strength. The experimental results also indicate that the dynamically induced frictional slip on the fault zone is associated with a complex frictional system, including seismic wave radiation, frictional slip initiation and normal stress vibration. Different from the dynamically induced frictional slip on the fault zone, the statically induced frictional slip causes a permanent increase of slip displacement along the shear loading direction. INTRODUCTIONAn earthquake mainshock may induce aftershocks by suddenly changing external stresses applied to another fault zone in the near field (Kilb et al., 2000) and by slightly perturbing a fault zone from a critical steady state to stick-slip faulting in the far field (Gomberg and Davis, 1996). The dynamically induced frictional slip on a fault zone has been recognized as the mechanism of earthquake aftershocks (Marsan and Lengliné, 2008; van der Elst and Brodsky, 2010). Although earthquake aftershocks have been extensively studied by many seismological methods, a simplified laboratory fault zone can provide possible interpretation on real faulting and detailed analysis on a friction process (Dieterich, 1979; Nielsen at al., 2010). According to a few laboratory experiments related to the dynamically induced frictional slip on a simulated fault zone (e.g., Uenishi et al., 1999; Johnson et al., 2012), the slip process induced by successive seismic waves exhibits continuous motions. However, it is unclear that fault slip response under each wave cycle and slip displacement accumulation under continuous wave cycles."

Jan 1, 2015

By D. Atkinson

"Porphyry molybdenum-tungsten mineralization on the east flank of Hudson Bay Mountain crops out over 5 km2 and is intersected to depths of 2 km. Features such as a hornblende-biotite aureole, mineralogical zoning and dike, vein and fracture geometries within lithologies of the Middle to Lower Jurassic Hazelton Group and Cretaceous Skeena Group reflect an intrusive complex, the Upper Cretaceous to Early Tertiary Hudson Bay Mountain stock which has been intersected by drill holes. The stock is believed to be the mineralizing agent. A southeast-dipping granodiorite sill has been outlined by drilling within the Hazelton Group. Molybdenite and scheelite veins cut all rock types; however, the granodiorite sill hosts a higher density of fine-grained, banded, quartz-molybdenite and pegmatitic quartz-molybdenite veins reflecting a competency contrast between the intrusive sill and other country rock. Due to the relative abundance of these veins, grade is higher within areas of the sill. Above the 15000£ cross-cut 20.6 million tonnes grading 0.401% MoS2 and 0.041% W03 have been defined. During exploration of the deposit sampling procedures had to be adjusted because of the nugget effect attributed to drill intersections of banded and pegmatitic veins.IntroductionMolybdenite was discovered in outcrop at the foot of Kathlyn Glacier on Hudson Bay Mountain and first reported by the Geological Survey of Canada in 1944. The deposit has several names: Hudson Bay Mountain or Glacier Gulch, both after its location, and Yorke-Hardy after the original staker.The deposit is on the east flank of Hudson Bay Mountain, 9 km northwest of Smithers, west-central British Columbia, within NTS area 93L/14 (54° 49' North, 127° 18' West, Fig. 1). Hudson Bay Mountain, on the southern edge of the Bulkley Valley, is a dominant topographical feature reaching 2590 m elevation. Mineralization is partly overlain by the Kathyln Glacier which is visible from Highway 16. Access to the 3100 m of underground development is from a portal at 1066 m elevation on the east slope of Hudson Bay Mountain."

Jan 1, 1995

By Albert W. Scragg

"THE ADMINISTRATION DEPARTMENT consists of six sections, all with their own supervisors, reporting to the superintendent of administration. Although each of these sections is uniquely separate, they all work together, in one department, to provide very necessary services.1. Accounting 2. Purchasing 3. Warehousing 4. Data Processing 5. Inventory Control6. Office ServicesThis department, which now numbers 108 people, had its birth in an office over a hardware store in downtown Timmins in 1964. Initially, only basic accounting and purchasing functions were performed and these, of course, were on a very small scale. The growth of the administration department is a function of the growth of the company."

Jan 1, 1974

By C. Larsen, E. Goodwin, E. Konigsmann

"This paper describes the development of an innovative effluent treatment process for cyanide and heavy metal removal from tailings wastewaters at Hemlo Gold Mines Inc. Golden Giant operation.The importance of minimizing dissolution of contaminants in the gold leaching circuit is discussed, as well as using recycled water in milling circuits to the fullest extent possible. Finally, a brief description of the role of natural cyanide degradation in the tailings pond is provided.Emphasis is placed on the need for overall water quality management to ensure minimum effluent treatment process costs and complexity while producing excellent quality effluents.1.0 INTRODUCTIONHemlo Gold Mines Inc. owns and operates its Golden Giant Mine located forty kilometres east of Marathon, Ontario. The Golden Giant mine is one of three gold operations exploiting the large gold orebody located in the Hemlo area. The milling facilities include two stage secondary crushing, three stage, closed circuit ball mill grinding with no reagents, thickening, cyanide leaching and carbon in pulp gold recovery unit operations. The average throughput is 3000 tonnes per day of 10 grammes per tonne gold ore. Figure 1.1 shows a schematic flowsheet of the operation."

Jan 1, 1989

By Charles W. Villiers

AS is well known, there are large and valuable deposits of coal in British Columbia, both on the mainland and on Vancouver island. These deposits are widely distributed over the Province. The chief sources of supply on the mainland are found in the Fernie and Princeton-Nicola districts and on Vancouver island in the Comox and Nanaimo districts. The coals range from a very high quality bituminous coal to lignite. On the Upper Skeena river there is said to be a very large deposit of anthracite or semi-anthracite, but this field has not been developed. Coal was first discovered in British Columbia on the north end of Vancouver island in the year 1835, but it was not until 1852 that coal mining was seriously undertaken by the Hudson's Bay Company at Nanaimo, where mining has been carried on continuously ever since that date. The production of coal in the Province continued to increase until the year 1910, when the annual output reached its peak at 3,100,000 tons and a total of 7,800 men were employed in the industry. Since 1910, the production has dropped steadily until, in 1934, only 1,347,000 tons of coal were produced and less than 3,000 men were employed. This continued decrease in production has in no way been caused by lack of coal reserves. It has been due entirely to curtailment of markets. I do not propose to discuss coal mining practice in British Columbia, where we have all sorts of mining conditions, including submarine mining. There is no lack of coal supplies for either industrial or domestic purposes, nor is there likely to be any shortage of coal in the Province for many generations. We have our mining troubles, which increase the cost of production, but there are no insuperable difficulties to prevent the extraction of a large and increasing supply of coal. Our main difficulty-in fact our only serious difficulty-is to find a market for our output, and we must consider means which can be evolved not only to conserve our existing markets but also to expand them, at any rate within the boundaries of Canada. I will therefore confine my remarks chiefly to the all-important factor of Markets for our coal.

Jan 1, 1936

By P. Müller, W. J. Przybylowicz, V. M. Prozesky, D. de Bruin

"Abstract -The common style of gold mineralization in the Basal Reef and other auriferous conglomerates of the Witwatersrand Supergroup comprises clusters of gold grains occurring interstitially to quartz and pyrite pebbles as well as gold accumulations attached to the surface of and infilling hairline cracks and fractures in round, compact, detrital pyrite. The latter textural association is generally interpreted as a result of remobilization of originally detrital gold during regional metamorphism and related hydrothermal fluid circulation. There is general agreement that, although gold solubility was Iow, ore modification occurred during the metahydrothermal event, but uncertainty exists about the magnitude and scale of gold remobilization .Micro-textural and chemical investigation of compact round pyrite and associated gold accumulation has established that gold is preferentially deposited on chemically heterogeneous pyrite surfaces. Combinations of alternating high- and low-As zones in pyrite result in mixed np-type conductivity accompanied by electron exchange and the reduction-driven deposition of gold at the cathode. This mode] does not explain gold accumulations which are not immediately linked to chemical heterogeneities and it is inferred that an additional control on the deposition of gold was exerted by physical defects which lead to zones of increased charge density and/or areas of focussed conductivity. The inferred precipitation mechanisms suggest that submicrocopic physical and chemical controls are the important factors that determined the sites of gold nucleation and that precipitation mechanisms based on physicochemical changes of the hydrothermal system were not involved. The Basal Reef contains on average close to 5% of round, detrital, chemically zoned pyrite which provides a large number of electrochemically active pyrite surfaces. The extremely effective electrochemical precipitation mechanism together with the low solubility of gold in Witwatersrand fluids is the main reason for the spatially restricted remobilization of gold in the conglomerate reefs."

Jan 1, 1994

By T. Sakai

Present authors have succeeded in single pass large draught rolling of AZ31 and ZK60A magnesium alloy sheets below 200 °C without heating rolls by raising rolling speed above 1000 m/min. Heavy reduction larger than 60% can be applied by single pass high speed rolling even at room temperature. The rolled sheets showed fine recrystallized microstructure by dynamic recrystallization. The improvement of workability at lower rolling temperature is due to temperature rise by plastic working. In high speed rolling, almost all of the work done by plastic deformation is converted into the heat that raises the temperature of the sheet during rolling because the heat did not flow out of the sheet by conduction and radiation within very short time.

Jan 1, 2006

By Michael Bowker

Au/TiO2 catalysts were prepared by incipient wetness impregnation and tested for the room temperature photocatalytic reforming of methanol in aqueous solution. These catalysts proved to be more active, on a molar basis, than Pd/TiO2. The dependence on loading of gold was different from that of palladium, showing a double maximum in yield at 0.1 and 2 wt. % with low rate below 0.01% and above 10%. A model is proposed for the reaction involving band gap excitation of titania electrons which are used to oxidise the methanol via adsorbed CO. With palladium, photoreforming of CO and water can be achieved, but this is much less effective on gold, presumably due to the much weaker bonding of CO on Au.

Oct 1, 2003

By J. Bigu, M. G. Grenier, S. Hardcastle

"This study was undertaken in a belt conveyor drift of an underground hard rock mine. The conveyor transported ore or waste from a crushing operation located upwind from the drift sampling locations. A 250 m section of this drift was selected and several types of measurements were taken. Average respirable concentrations in the drift were 0.43 mg/m3 and 0.19 mg/m3 for total and silica dust, respectively. From the respirable dust concentration profile along the drift, it may be possible to estimate the contribution from extended sources such as dust produced by the belt and return idlers.The airborne dust in the drift had an average mass-median aerodynamic diameter of 4.2 micron. A continuous dust monitor showed that the crushing operation produced fairly high dust concentrations (sometimes greater than 4 mg/m3) over short periods of time.IntroductionAirborne dust in the respirable range is known to be the cause of various forms of lung ailments . In underground mines, respirable dust sources are created at many stages of production. All mining operators are responsible for de signing and establishing means of reducing airborne dust. In some cases, sources of dust are well defined and suppression methods are standard.In the case of interest here, the airborne dust cloud was formed from the contribution from many sources, which may be either discrete or extended. At the experimental site, the discrete or point sources were the crushing operation and the belt conveyor transfer point (tail pulley). These sources may be controlled by proper dust capture and scrubbing systems as well as dilution ventilation. Examples of extended dust sources in the area include dust produced by the re-entrainment of settled particles along the drift. Ventilation air movement and vehicular traffic both contribute to this phenomenon. Dust produced by the conveyor is another example of an extended dust source. Caked deposits on the return strand and idlers as well as the transportation of dry material on the belt, can be major contributors. Proper wetting of roadways and muck as well as proper belt cleaning techniques can help reduce these emissions. The cleaning apparatus, used on the belt where these experiments were conducted, is shown in Figure I. These and other belt cleaning techniques are described in more detail elsewhere."

Jan 1, 1987

By Ralph W. Edie

"IntroductionTHE GOLDFIELDS AREA in northern Saskatchewan has be-come important in recent years because of numerous discoveries of pitchblende. The area is underlain by rocks of Precambrian age and, because of metamorphism and hydrothermal alteration, the geology in the vicinity of the pitchblende deposits is exceedingly complex and presents a challenge to all geologists •working in the district. This paper is a contribution to the geological literature of the area and presents a description of rock types, supplemented with petrographic, chemical, and spectrochemical data.Field work in connection with this paper was carried out during the summers of 1948, 1949, and 1950 while the writer was employed as assistant geologist for the Crown Corporation, Eldorado Mining and Refining ( 1944), Limited, Gold-fields area. Laboratory work was undertaken at the Massachusetts Institute of Technology during the winter months of 1949-50 and 1950-51 and extended through the summer of 1951.With the exception of SiO2and FeO, all of the new analyses ( 1) presented were carried out by quantitative spectrographic techniques under the supervision of Dr. L. H. Ahrens at M.I.T. Many of the techniques have only recently been developed at that Institute and detailed laboratory procedures have not yet been published."

Jan 1, 1952

By I. G. Townsend, S. A. Buckley, C. I. House

"SummaryBritish Petroleum plc is developing a new gold recovery process known as coal gold agglomeration (CGA) for the recovery of gold from its ores. Liberated gold grains are recovered with high efficiency by adhering to agglomerates of coal and oil. The process is simple, can recover gold grains down to very fine sizes, avoids the large scale use of cyanide and provides the industry with an important new process option.A technical appraisal of the process has been performed on an extensive range of gold bearing materials. Ore types have been identified from which high gold recoveries can be achieved. A spreadsheet based computer program has been used to estimate the preliminary capital and operating costs of the process. Comparison with established gold production costs shows that the process costs of CGA, on the appropriate ore types, are potentially very attractive, which will enable economic treatment of lower grade ores than is currently possible using conventional cyanidation. Treatment of known placer deposits or gravity concentration plant tailings may be the most rapid means of demonstrating the process at a commercial scale prior to more widespread applications.1. INTRODUCTIONWestern world gold production for the 1980s has shown rapid growth sustained by a demand for gold at a favourable price (Fig. 1). Heap leaching and CIP/CIL operations have been responsible for the major part of new production during the 1970s and 1980s with present overall production costs averaging US$200/oz in Canada, USA and Australia and US$265/oz in South Africa [l]. A great deal of research and process development effort in the 1980s has been towards the treatment of refractory ores. Operating costs for the economic processing of these ore types by currently available routes are around US$300/oz [2]."

Jan 1, 1989

By G. F. Flaherty

THE property of Tashota Goldfields, Limited, in the Lake Nipigon area, Ontario, is located about 4 miles west of Onaman lake and 16 miles by winter road south-southeast of Tashota station on the transcontinental line of the Canadian National railways. The mine, formerly developed to a limited extent under the name of Tashota Gold mine, has, since late in 1933, been under the management of Minefinders Limited, who, in 1935, brought it into production on a 60-ton per day basis. During the winter of 1934-35, the writer was geologist at the property. The geological structure in the immediate vicinity of the mine workings lends itself well to analysis on the basis of the mechanical principles of folding. Since structure is of prime importance in the localization of the ore-shoots and of the host shear-zones at the property, the correlation of all structural details and their mechanical interpretation forms a working hypothesis of structural control for the direction of exploration and development work. It is believed that the structural relations here set forth may be found applicable in part, or at least suggestive, in working out the relations of ore-shoots to structure in the Sturgeon River area to the south, and in the Little Long Lac area to the southeast (Figure 1).

Jan 1, 1936

The use of QemSCAN in providing mineralogical input to detailed ore and product characterization has proved of immense value in recent years. In this paper, a brief review of selected Cu-case studies is presented to demonstrate the versatility of automated, quantitative mineralogy by QemSCAN. This versatility ranges from measurement and analysis strategies through to data processing and presentation. As a rapid diagnostic service, it is common to find that only grain size, the degrees of liberation and/or ore mineral modal mineralogy are of interest. By contrast, the detail afforded by the simultaneous determination of both gangue and ore minerals can alert mineral engineers to fatal flaws and attributes deleterious to processing that are directly a function of silicate and other gangue mineralogy. Examples of the latter effects include the influence of micaceous minerals and acid consuming species, while the former include fluorine minerals, which can provide both processing and environmental challenges.

Jan 1, 2007

By J. R. Pronovost, P. M. Tiley, D. W. Watts

"In 1980, J.S. Redpath Limited were retained by Dickenson Mines Limited to increase hoisting capacity from 700 to 1000 tons per day. The hoisting capacity of the present skip-over-cage system could not be increased significantly through design modifications. The other constraint was a minimum of disruption to the current production. The Dickenson shaft was a three-compartment shaft from surface to the 8th level and four compartments before the 8th to the 23rd level. The solution to the problem was to remove the services from the shaft man-way compartment from the 8th level to surf ace by drilling a borehole close to the shaft and rerouting those services through the borehole to the 8th level. A service compartment would then be available from surf ace to the 23rd level.By providing a service hoist in this compartment, the skip hoist would then be free to produce the 1000-tons/day required production. This paper will describe the search for the required hoist and the friction hoist selected for the project, and trace the design modifications required to modify the hoist to suit the Dickenson application and satisfy the Department of Labour safety requirements.The paper has been co-authored by J.S. Redpath Limited and C.L. Tiley Associates, who participated in the design changes and eventual commissioning of the hoist.IntroductionIn the earl y part of 1980, J.S. Redpath Limited conducted an engineering study on the Dickenson Mines Limited No. 1 Shaft materials handling system. The object of the engineering study was to investigate the possibility of increasing the tonnage hoisted from the No. 1 Shaft complex by adding a service cage compartment and service hoist. This would permit utilization of the existing hoisting plant solely for production hoi sting. A further consideration of the engineering study was that any alterations had to be accomplished with little, or no, interruption to production."

Jan 1, 1982

By J. R. Pronovost, P. M. Tiley, D. W. Watts

"In 1980, J.S. Redpath Limited were retained by Dickenson Mines Limited to increase hoisting capacity from 700 to 1000 tons per day. The hoisting capacity of the present skip-over-cage system could not be increased significantly through design modifications. The other constraint was a minimum of disruption to the current production. The Dickenson shaft was a three-compartment shaft from surface to the 8th level and four compartments before the 8th to the 23rd level. The solution to the problem was to remove the services from the shaft man-way compartment from the 8th level to surf ace by drilling a borehole close to the shaft and rerouting those services through the borehole to the 8th level. A service compartment would then be available from surf ace to the 23rd level.By providing a service hoist in this compartment, the skip hoist would then be free to produce the 1000-tons/day required production. This paper will describe the search for the required hoist and the friction hoist selected for the project, and trace the design modifications required to modify the hoist to suit the Dickenson application and satisfy the Department of Labour safety requirements.The paper has been co-authored by J.S. Redpath Limited and C.L. Tiley Associates, who participated in the design changes and eventual commissioning of the hoist.IntroductionIn the earl y part of 1980, J.S. Redpath Limited conducted an engineering study on the Dickenson Mines Limited No. 1 Shaft materials handling system. The object of the engineering study was to investigate the possibility of increasing the tonnage hoisted from the No. 1 Shaft complex by adding a service cage compartment and service hoist. This would permit utilization of the existing hoisting plant solely for production hoi sting. A further consideration of the engineering study was that any alterations had to be accomplished with little, or no, interruption to production."

Jan 1, 1982

By Chen Xia, G. Deschenes, Wan-Tai Yen

"Ammonium thiosulphate is a potential replacement for the cyanide in gold leaching. However, the high reagent consumption hinders its practical applications. In order to reduce the thiosulphate consumption, chemical additives were used. The gold leaching tests were conducted on a sulphide copper-bearing gold ore with 0.3M thiosulphate, 0.03M copper sulphate and 3M ammonium hydroxide solution at 44% solids and pH 10.2. Sulphate, sulphite, amino acid and chelating agents were initially used as additives. It was found that chelating agents (EDTA and NTA) could reduce the thiosulphate consumption from 30 kg/t to 17.8 kg/t with some increase of gold extraction. The improvement from other additives was not significant. Other approaches were also attempted to reduce thiosulphate consumption with some success. The thiosulphate consumption could be reduced to about 17 kg/t by reducing copper sulphate concentration fiom 0.03M to 0.0015M; adding 0.04M of EDTA; replacing copper sulphate with 0.001M of nickel sulphate. The increase of pulp density fkom 44% to 60% solids could reduce the thiosulphate consumption to 17 kg/t as well. Limiting the dissolved oxygen content by sparging nitrogen reduced the thiosulphate consumption further to 10 kg/t. It could be concluded that the regulations of copper and oxygen supply in the lixiviant were the keys to reduce the reagent consumption.INTRODUCTIONCyanidation, as the predominant gold leaching method, has been used in mining industry for more than a century. The low reagent requirement and the high performance are the reasons for its great success. However, cyanidation cannot deal with ores containing large amount of copper, nickel, arsenic and zinc minerals. This type of ore may consume more reagents and result in a poor gold extraction. On the other hand, the carbonaceous materials may preg-rob the gold from pregnant solution and make cyanidation a problem leaching method. Further more, the high toxicity of cyanide represents another challenge to modern gold mines. In the beginning of the year 2000, an environmental disaster caused by an accidental spill in Yugoslavia was broadcasted world-widely (Gurevitch 2000). Gold mine operators are facing higher social pressures and increasing costs on environmental protections. The usage of cyanide in mining industry has been banned in some countries and locations such as Czech Republic, Japan, Turkey, California, Colorado, Wisconsin and Montana States. Thus, a non-cyanide lixiviant is required."

Jan 1, 2002

By Ralph W. Edie

"IntroductionTHIS PAPER deals with chemical and mineralogical changes in wall-rocks associated with pitchblende mineralization in the Gold-fields area of Saskatchewan. The localities at which the rock specimens studied were collected, and descriptions of the various rock-types referred to, are given in a previous paper by the author (5).The geological field work upon which this paper is based was carried out while the writer was employed by the Eldorado Mining and Refining Company during the summers of 1948, 1949 and 1950. The laboratory work§ consisted largely of quantitative spectrographic analyses for both major and minor elements, supplemented by an examination of 250 thin sections of both altered and unaltered rocks.Character of the AlterationHydrothermal alteration, with associated pitchbende mineralization, is widespread in the Goldfields area of Saskatchewan. The most intense alteration is restricted to the immediate vicinity of fault or breccia zones, but large areas are affected to a minor extent.In detail, the relationship between alteration and pitchblende mineralization is complex, as individual veins do not in general have separate alteration halos. Pitchblende generally occurs in gash-like calcite veins or stringers in wide, fractured zones associated with faulting. Large, lenticular and tabular masses of slightly to intensely altered rock occur in the same wide fracture zones as the mineralized veins. However, vein deposition appears to be-long to a later fracturing period, after hydrothermal alteration was more or: less completed. Generally, the veins transect and are confined to highly altered rock, but on the other hand many highly altered zones intersected in diamond drill-core are barren of mineralized veins."

Jan 1, 1953

By Pierre Sauvé, Guy Perrault, Armand Savoie, Pierre Trudel

"La Mine Doyon est une entreprise détenue à parts égales par Cambior Inc. et par Minerais Lac Ltée qui en est l'opérateur. Les statistiques de production au 1"" janvier 1990 indiquent que, depuis le début de son exploitation (1980), 10.3 Mt de minerai d'une teneur moyenne de 5,9 g Au/t ont été usinées. Les réserves sont estimées a 10,4 Mt à une teneur moyenne de 6,6 g Au/t jusqu' à une profondeur de-450m.Trois zones minéralisées sont présentement en exploitation. Ces zones sont caractérisées par la présence de veines de quartz-pyrite accompagnées localement de chalcopyrite. Les roches encaissantes sont les schistes a séricite (zone# 1), les roches volcaniclastiques de composition felsique (zone #2) et intermédiaire (zone #2, zone ouest) ainsi que les roches intrusives appartenant au pluton de Mooshla (zone ouest). Toutes ces roches ont subi un métamorphisme régional dont l'intensité correspond à la limite supérieure du facies schiste vert ( -425°C}.Les zones minéralisées sont situées à I' intérieur des zones de déformation et d'altération les plus intenses. L'étude des structures mineures nous indique que la région a subi plusieurs épisodes de déformation ductile a fragile qui sont antérieurs, contemporains et postérieurs al a minéralisation. L'analyse structurale indique également que la déformation majeure est associée à une importante phase de compression orientée N-S a NNE-SSW.L’ensemble des observations suggère que la minéralisation et I' altération associée sont de type épigénétique. La mise en place du minerai se serait effectuée à la fin de l'épisode principal de métamorphisme et de la déformation."

Jan 1, 1990

By K. V. Konigsmann

"Mattagami Lake Mines Ltd operate a zinc-copper mine with an annual output of about 200,000 tons of zinc and 30,000 tons of copper concentrates. Zinc concentrates arc shipped to a company owned smelter in Valleyfield (a distance of 690 miles), for Export to Quebec City and also to Josephtown, Pennsylvania (1,060 miles, Figure 1.)The protection of concentrates in open gondola rail shipments has been a matter of concern since operations commenced. Considerable financial losses did occur at times because of wind erosion. Operating difficulties were also encountered by customers because of excessive moisture accummulation in the concentrates. Test shipments made in 1969 established the magnitude of losses in open cars. The results and subsequent investigations at our mines and elsewhere confirmed that load protection is an economic necessity.Many types of covers were experimented with, more or less successfully. In 1972 we agreed on a joint program with Dupont of Canada Limited. A new type of cover was developed by early 1973. It has been in use since, undergoing several improvements as experience accumulates."

Jan 1, 1975

By Salvador Gómez, Rodolfo Espinosa, Jaime Bravo, Leopoldo Gallas

"Compañia Fresnillo, S.A. de C.V. - Proaño Mine, is owned by Industrias Peñoles S.A. de C.V. (Peñoles). The Proaño Mine, is one of the richest silver underground mines in the World, and for this reason, production capacity has always being expanded, based on generated reserves. Reserve generation has not being an easy task as this is a vein type deposit.This paper presents the growing stages at the Concentrator, for about the last twenty years; which can be listed as follows:1.,Increase in capacity from 1,000 to 4,500 tonnes per day, at several stages; on the same infrastructure, and without production interruptions.2.,Addition of a new flotation circuit to recover a zinc concentrate with a high silver content.3.,Installation of a semi-autogenous (SAG) mill, to replace a conventional crushing circuit. 4.,Modernization. Installation of an on stream analyser, an automatic reagent dosification system, 4500 ft3 unit cells, pressure filtration, a closed circuit video system to help process monitoring, an automatic ball addition system for SAG and ball mills, and on-line particle size analysers.5.,Silver recovery from old tailings, installing a 2,350 tonne per day treatment plant.INTRODUCTIONIndustrias Peñoles, S.A. de C.V. (Peñoles)Peñoles’ mission is to add sustainable value to non-renewable natural resources. Peñoles seeks to: build long-term shareholder value; provide customers with the highest quality product services; maintain productive long-term relationship with suppliers; develop and promote the capabilities of their personnel; foster mutually beneficial relationship with the communities in which operates; protect and preserve the environment."

Jan 1, 2002