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By K. Meshinchi Asl

In this study the effects of T4 and T6 heat treatments on microstructural characteristics of AZ91 alloy containing Rare Earth elements have been investigated. Formation of intermetallic Al1 1RE3 needle shape particles which have a good thermal stability reduces both formation of ß(Mg17A112) and discontinues precipitation in AZ91 alloy which are dominated at the grain boundaries and are responsible for poor mechanical properties specially in elevated temperatures. For AZ91-RE samples both T4 and T6 heat treatments led to a continuous precipitation of ß particles at the grain boundaries after aging. However, in AZ91 samples (with no Rare Earths) precipitation was discontinuous at grain boundary areas. This type of precipitation is one of the main reasons of poor mechanical properties of this alloy at elevated temperatures.

Jan 1, 2007

By John C. Loretto

"The paper identifies two of the main problems encountered in recent hydrometallurgical plants for the recovery of gold and silver: firstly, the plant recovery is lower than anticipated from the testwork; secondly, the metallurgical accounting figures cannot be reconciled.The principal reasons for the plant recovery being lower than the testwork are discussed, together with solutions that can minimize these problems both during the design stage and during the plant operation after the problems have manifest themselves.The reasons for the difficulties in metallurgical accounting are analyzed by reviewing the various components of the plant figures. Recommended solutions are given for minimizing this problem and the realities of obtaining accurate figures are discussed.IntroductionThe start-up over the last few years of new hydrometallurgical plants for the recovery of gold and silver has brought to the surface again a number of problems. Most of the problems have existed for some time and they manifest themselves mainly in two ways. Firstly, the plant results do not agree with the metallurgical testwork figures; secondly, the metallurgical accounting figures do not balance.Metallurgical TestworkThe plant results not agreeing with testwork figures are mainly due to:a) testwork samples not representative of the eventual plant feed;b) misinterpretation or misunderstanding of testwork ;c) plant losses;d) plant design not allowing testwork results to be achieved;e) operating deficiencies."

Jan 1, 1982

By Frank Ebbutt

Introduction The property of the Britannia Mining and Smelting Company, Limited, is situated on the east side of Howe sound, about six miles from its head. It is roughly thirty miles by water from Vancouver, one of the important ports of the Pacific and the industrial and financial centre of British Columbia. Howe sound is navigable for ocean-going vessels and Britannia Beach is a daily port of call for the commodious boats of the Union Steam-ship Company, sailing from Vancouver. Few mines are so ideally situated or have so many or varied natural advantages. Copper was first found on Britannia mountain in 1888, by Forbes, but it was not until 1898 that five claims were staked here by Oliver Furry, a trapper. It is from these claims that the major production during the past thirty years has come. In 1900 the Britannia Copper Syndicate was formed and development of the property was commenced. In 1903 the late Grant B. Schley obtained control, and through his efforts the Britannia Mining and Smelting Company was organized in 1908 as a subsidiary of the Howe Sound Company. Since that time, a persistent and progressive policy has been followed, which has resulted in a prolonged and profitable operation. The country in the immediate vicinity of the mine is marked by strong relief, with mountains rising abruptly from tide-water to elevations of 5,000 feet and more. Two broad transverse valleys deeply dissect the area. These are the valleys of Britannia creek and Furry creek. The region has under-gone prolonged and relatively recent glaciation. Over much of the surface there is deep overburden and dense vegetation. The geology of the mine and vicinity has been described in reports by S. J. Schofield (1), H. T. James (2), J. G. Barry, and others (3). The present writer is in accord with much of this literature on Britannia, but during recent years, extended observations made underground have shown that the 'quartz porphyry', or 'mine porphyry', of several of the earlier writers is not the host rock to the commercial mineralization; and he contends that the mineralization occurs in highly altered phases of a complex series of ruffs, flows, and pyroclastics and their autoclastic metamorphosed products.

Jan 1, 1935

By G. N. Carlson, C. H. Hazelroth, D. R. Dorrance

"Located on the north shore of the St. Lawrence River at Pointe Noire, Quebec are the agglomeration and ship-ping facilities of the Wabush Mines complex. Here, the specular hematite concentrate from the Scully Mine is received for further processing. Modern facilities for handling the ore, either to the 1plant or to stockpile, provide quick and efficient operation of the ore receiving station. Physical preparation of the ore for balling is accomplished with regrind ball mills, filters, bentonite crushing and drying facilities, pumps and related conveying circuits. Rotating table feeders deliver the reground and de-watered ore from storage bins to balling drums, where green ball or green pellet formation is achieved. The green balls are then conveyed to the indurating section. Three Dravo-Lurgi travelling grates, producing a total of 6,000,000 long dry tons of pellets per year, are used in the indurating phase of the operation. These grates, having 38 windboxes and firing at a temperature of 2,500°F, harden the pellets for shipment to various blast furnaces throughout the world."

Jan 1, 1969

By E. A. Hart, J. E. Gill

"The property of Arntfield Mining Corporation, formerly Arntfield Gold Mines, Limited, covers an area of 2,110 acres and lies in Beauchastel township, western Quebec. The Francoeur mine lies to the west, and to the east are the West Wasa and Wasa Lake properties.The property was staked in September, 1923, by the late F. S. Arntfield. The early surface work was concentrated in the west part of the property along the Francoeur-Arntfield shear zone. The zone was opened by No. 1 shaft, which was sunk for an inclined depth of 250 feet. A series of silicified lenses were discovered farther east, where No. 2 shaft was later raised to the surface. A third shaft explored a shear zone about 1,900 feet to the east, where No. 3 shaft orebodies were developed.The mill was built at No. 3 shaft and production commenced in July, 1935, at 125 tons a day. This was increased to 280 tons by 1938, and later to 350 tons. The mine continued operations on this scale until April, 1942, when the exigencies of war necessitated closing. The Company was reorganized in 1944 and underground development was resumed in June, 1945. The total value of gold and silver produced to April, 1942, was $2,011, 755 from 529,987 tons of ore.ROCK TYPESThe area is underlain by highly deformed and altered Keewatin volcanics overlain by little deformed Cobalt sediments along the south boundary. The lavas in the vicinity of the mine workings are rhyolite, trachyte, andesite, and a flow breccia of intermediate composition. The fragmentals range from fine, well-bedded tuffs to coarse agglomerate in which acidic and basic horizons can be distinguished.The intrusive rocks are diorite and quartz-feldspar porphyry in the form of stock and sills, and narrow dykes of mica lamprophyre and syenite porphyry."

Jan 1, 1954

By C. M. Campbell

In his report on the Coal Resources of Southern Vancouver Island, Mr. J. D. MacKenzie stated that: "For various reasons it has been imagined that the coal deposits of Vancouver Island are extremely large and readily available." "Unfortunately," he added, "neither of these assumptions is correct." The chief disability under which the Island mines now labor does not concern the extent of the deposits. There is ample coal for the present demand. It does, however, concern the availability of the coal. If it were readily available the fuel-oil competition would not be serious and there would be no competition with Alberta, American, Welsh, or Australian coal along the Pacific Coast, for Vancouver Island coal could be produced at a price that would cut out all competition. The outstanding operating difficulty common to all Island mines is the extreme irregularity of the coal seams. To most people a coal seam is synonymous with uniformity, and in most coal seams a condition found at one point will be repeated at other points in the same seam throughout the basin. The accompanying drawings show how very far this is from being true in the Cassidy mine, which, in many respects, is typical of Vancouver Island mines. Figure I is a plan covering about 160 acres of the Douglas seam, the only workable seam in this part of the district. The area shown represents what has been the best producing part of the mine and indicates the very large percentage of the seam where the coal is either entirely lacking or so small in amount that it cannot be profitably recovered.

Jan 1, 1924

By L. R. Bower

"This paper describes a highly versatile variable speed unit with a torque multiplication feature as a direct replacement for a fluid coupling .The unit is comprised of a modulating clutch with torque converter and lock-up options.The UCD does not start or stop the motor. This is carried out in the normal manner.The UCD continually monitors and rapidly regulates the output speed to the requirement of a set point demand from input signals or a pre-set program with full manual override.The pre-set program can include start and stop ramps, top speed and minimum speed regulation and also mid-speed set point with security for man-riding, etc. Speed variation is from zero to 100% on a constant duty basis.The input signals can be from any source, e.g. belt weigher. load profile bunker probes, mine monitoring system, etc.The UCD when fitted with a torque converter has a torque multiplication feature which automatically provides a starting torque up to two and a half times greater than the full load torque without exceeding the normal motor power levels.IntroductionIt is common practice in the mining industry to drive conveyors, whether they be belt or chain, through a transmission system incorporating a fluid coupling between the driving motor and gear-box .However, there are drawbacks and in an effort to attain a better degree of drive and control, two-speed motors - inverters cycle- converters - hydrostatic drives, etc ., have been introduced."

Jan 1, 1986

By M. Bourassa, R. del Villar, S. St. Arnaud, J. Valenzuela

"Autogenous grinding is used quite frequently for mineral comminution as a result of its lower capital and operating costs. However, it is more difficult to control than conventional grinding, particularly when the autogenous or semiautogenous mill is the only comminution stage (i.e. no secondary grinding is available). Analysis of the control strategy used then becomes extremely important, a task that is greatly simplified by the use of an empirical dynamic simulator:This paper presents the methodology used in the development and the calibration of such a simulator for the autogenous grinding circuit of an iron are concentrator: The various steps are described: industrial data acquisition, preliminary treatment of the gathered information. and empirical modelling of the process. Finally, both the actual and the proposed control strategies are compared using simulation results.This exercise has shown that the variability of some of the controlled variables could be reduced through a better handling of the water addition and the use of filters on some of the signals used for control purposes. The reduction in variability of critical variables, such as power draw, would allow their average value to be increased without the risk of exceeding their safety values. Some advanced control techniques were also tested, with interesting results."

Jan 1, 1995

By B. Huffman

This paper examines several new trends in the design and application of linings for copper melting shaft furnaces including the use of large shapes, monolithic back-up linings and improved refractory engineering to significantly reduce refractory installation time, diamond saw blade costs, fuel and down-time. The net results are shown to be dramatically increased refractory service life, reusable safety linings, elimination of hot spots and lower refractory disposal costs.

Jan 1, 2007

By Michel Carreau

Presentation topic Introduction to Renewable Power in Remote Mining Industry Trend What are the Challenges and How to address them Acceptability (Management Buy-in) ? RP not core business to mining company Significant upfront costs Project Risks - Technological and Delivery Wind and solar power variability Operating hybrid power (Operator Buy-in) Conclusion Introduction ? RP at Remote Mining Sites Mining Project Cost Energy represents 25% of mining project CAPEX Energy represents 25% of OPEX Diesel, HFO, ? cost : 30+ cents/kWh RP - Proven technology - Excellent track record ?Wind (20 years), Solar PV (10+ years)? Hundreds of GW installed ?Reliable, High availability, very small OPEX. ?Wind/Solar cost : 15 to 22 cents/kWh (with good resource) ?Potential 10% to 20% Reduction in net cost of energy ?Price certainty for 20 to 25 years

May 1, 2013

By Earl T. Hayes

This paper briefly reviews the laws enacted in the United States governing the coal miner. It discusses amendments to the Coal Mine Safety Act and describes the provisions of the Metal and Non-Metallic Mine Safety Act.

Jan 1, 1969

By J. C. Farge, G. G. Jacox

"The effect of composition and process variables on the properties of Marmet and modified Ni-Hard slugs will be discussed. The effect of shape on the over-all performance of grinding media and its relationship to the end product has been investigated and these results will be reviewed. The cost effectiveness of slugs versus balls has been well documented under various operating conditions and this will be presented in detail. IntroductionThe selection of grinding media is based on the cost-to-wear ratio combined with the consideration that it must stand repeated impacts without breaking. The specific consumption of grinding balls and slugs depend s primarily on their microstructure, which, in turn, is controlled by chemical composition and by the processing condition s to which they are subjected during manufacture.The first part of the paper deals with the optimization of alloy content to produce cast iron slugs with microstructures consisting essentially of marten site and carbide and with hardnesses of 650 B.H.N. and higher. The second part deals with the use of cast iron slugs to replace forged steel balls in milling operations. Tests indicate that the shape of the media has little if any effect on results and that the hardness and microstructure of grinding media will determine its relative performance. Where price is equal under similar milling conditions, the cost effectiveness of cast iron slugs is superior to that of forged steel balls.In order to understand the role of alloying elements in cast irons, it is judicious to consider the microstructural changes which occur during solidification and subsequent cooling, particularly from above the eutectoid temperature. Solidification starts with the formation and growth of dendrites of austenite. As temperature decreases, an eutectic nucleates and grows between the primary austenite dendrites. Immediately after solidification, the structure consists of proeutectic austenite and of the eutectic of primary carbides and austenite. On cooling to room temperature, austenite can be retained or transformed to pearlite, bainite, martensite or mixtures thereof. It is necessary to prevent decomposition of austenite into pearlite by adjusting the alloy content. For best abrasion resistance, the microstructure at room temperature should consist essentially of martensite and carbide. These types of irons are known as ""martensitic irons "". Depending on the carbon content of the austenite and cooling rate, "" as-cast"" martensitic irons will contain different proportions of martensite and retained austenite. The more carbon in solution in the austenite, the lower is the temperature at which the martensitic transfoemation takes place. By the time room temperature is reached ., the transformation is seldom complete, and the end product is generally a mixture of martensite and retained austenite."

Jan 1, 1980

By C. Jay Hodgson, Adrienne C. L. Larocque

Abstract -The Mobrun VMS deposit in northwestern Quebec does not fit the classic Noranda­ type model, but exhibits characteristics more consistent with a Mattabi-type deposit. The orebodies are underlain by fragmental volcanic rocks indicative of explosive volcanism in shallow water. Felsic volcanic rocks are more abundant than mafic rocks. Alteration assemblages comprise chlorite, carbonate, sericite, and quartz. Broad semi-conformable alteration occurs high in the footwall to the 1100 lens. Mobrun occurs higher in the stratigraphic sequence than most of the other deposits in the Noranda camp. In this part of the stratigraphy, zones of pervasive carbonatization may be more useful guides for exploration than zones of silicification.

Jan 1, 1993

By Arthur Brant

STEEPROCK LAKE (Figure 1) lies about two miles north of Atikokan, a village approximately one hundred and forty miles west of Fort William and one hundred miles east of Fort Frances on the Canadian National railway. The possible presence of hematite beneath the waters of Middle arm was inferred by early geological investigators (1890-1903) from the dense hematite float found on the southerly shores of this portion of the lake (1). A dip-needle survey of Middle arm, undertaken in the winter of 1930-31 by J. G. Cross, indicated two areas of high magnetic attraction which Mr. Cross thought might be due to magnetic iron oxides associated with possible hematite bodies. Bedrock could not be reached by the ineffectual hand-drilling so courageously attempted, and further work was abandoned. It was not until 1937 that Mr. Jos. Errington, of Toronto, convinced of the possibilities, determined to support Mr. Cross to the extent of several thousand feet of drilling. During the winter of 1937-38, holes Nos. 1, 3, 4, 5, and 13 were put down (see Figure 1). The first four of these holes demonstrated that the areas of magnetic attraction outlined by the dip-needle survey east of the Narrows and southwest of Elbow point were due to ash rock (2). As a result, Mr. Cross decided to investigate the bordering areas of low magnetic attraction and selected a location near the high ferruginous lime (3) point in the northeast of Middle arm. Dense, hard hematite beneath approximately 350 feet of water and clay was struck in the first hole, and, before the end of the winter's drilling, hematite had been encountered in holes Nos. 6 to 13 along a straight line 700 feet in length (see Figure 1). In the meantime, the Steerola ( 4) Exploration Company had been formed to continue development and already, in the spring of 1938, W. D. Neeland, the Company geologist, had come to the conclusion that the most probable location for possible hematite was at the ash-lime contact. Accordingly, during the summer, drilling was continued off-shore in holes Nos. 15, 25, and 27 (see Figure 2) toward possible hematite bodies inferred by Mr. Neeland.

Jan 1, 1940

By A. F. Abd El-Rehim

The behavior of both transient and steady state creep of Al-4.5 wt% Cu and Al-4.5 wt% Cu-0.1 wt% In alloys was investigated using a constant stress where torsional oscillations of different frequencies and shear strain amplitudes were operated at various working temperatures. An augment in both transient and steady state creep rates was observed by increasing both frequency and shear strain amplitude of the applied oscillations. The mean values of the activation energy of both alloys for both creep stages were found to be equal to that quoted for dislocation intersection mechanism.

Jan 1, 2006

By L. Fernandes

A two level factorial study was undertaken to investigate the relative impacts of factors affecting the kinetics of polytetrafluoroethylene, PTFE, assisted pressure oxidation of chalcopyrite. A copper flotation concentrate, principally composed of chalcopyrite, was leached in 850 mL of leach solution under conditions similar to those of the CESL process. The factors manipulated were: the amount of 1/8" PTFE beads added (100 g or 650 g), oxygen pressure (690 kPa or 1030 kPa), and concentrate addition (10 grams or 65 grams). Copper extraction data, which indicated complete leaching under certain conditions, were fit using a shrinking core model from which rate constants were estimated and further used to generate a statistical model containing only the factors of significance and their interactions. Results indicated a strong positive effect of PTFE addition and a strong negative effect of increasing pulp density. A weak negative interaction between increasing PTFE addition and pulp density was attributed to PTFE/concentrate agglomeration.

Jan 1, 2014

By J. F. Wright

Gold-bearing quartz veins and replacement chalcopyrite deposits are the two important types of metallic mineral deposits of the east central Manitoba mining district. The gold-bearing veins occur along Manigotagan valley, northwest for 25 miles from Beresford lake, and the copper deposits along Oiseau valley, between Oiseau lake and the east end of Lac du Bonnet. Lithium-bearing minerals of possible commercial value have recently been discovered in pegmatite along Winnipeg river about 10 miles east of Point du Bois. There are also prospect pits with showings of galena, sphalerite, cobaltite, pentlandite, nickeliferous pyrrhotite, arsenopyrite, pyrite, molybdenite, cassiterite, and other minerals, but the various occurrences of these minerals, as exposed, are small. The bedrock and mineral deposits of this mining district are Precambrian and resemble in many respects the formations and mip.eral occurrences of western and northern Ontario. Although prospectors visited eastern Manitoba at intervals during the last fifty years, effective prospecting did not begin until 1913 or 1914, and not until 1923 were skilfully directed, systematic explorations undertaken. It is true, that between 1913 and 1923 considerable sums were expended in a number of attempts at mining and milling the gold-quartz ore, but these enterprises failed partly through poor management or attempts to develop veins that were too small or too low-grade to be worked at a profit under the existing conditions of transportation and power supply.

Jan 1, 1925

By J E. McMynn

The development of the Granduc mine presents a number of problems which are peculiar to its location and surrounding terrain. Because the development tunnels portal onto an area which is covered by an extensive glacier, and the mountain-side is subjected to dangerous snow slides, it was decided to construct an underground powerhouse to supply the necessary electric power and compressed air. This paper deals with the special problems inherent in the design and -construction of an underground plant. It involves the installation of diesel-electric generating equipment having an aggregate capacity of 1,050 kw.,and of air compressors with a total capacity of 2,400 cfm. Items dis-cussed include the selection of equipment to meet site conditions, the ventilation and cooling of the underground room, and the protection of personnel and equipment from explosions and fire. A short discussion on the automatic supervisory and alarm installation is also included. THE Granduc mine is located 135 miles north of Prince Rupert and 25 miles north of Stew-art. This seems quite accessible, mileage-wise, but, due to mountains,

Jan 1, 1963

By J. -F. Lepage, M. A. Tomlinson, K. K. Murray

"The Éléonore mine, located in the James Bay region of Northern Quebec, generates a gold bearing flotation concentrate rich in pyrrhotite. Direct leaching of the finely ground concentrate results in high cyanide consumptions and poor recoveries, so effective pre-treatment to passivate the pyrrhotite is required before leaching. Following a number of process upsets at the mine, test work was performed to better understand the requirements for passivation so a more effective operational strategy could be implemented. This paper outlines the testing and implementation of the new strategy at Éléonore.ÉLÉONORE CONCENTRATOR The Éléonore mine is located 800 km north of Montreal, in the James Bay Region of Quebec, Canada. The ore, containing gold disseminated in sulfide minerals and free fine gold in silicate gangue, is crushed in a two-stage crusher plant before being ground in a single 9,000 kW ball mill. The ball mill is in closed circuit, with about 25% of the cyclone underflow passing through a gravity plant with two, 48” Knelson concentrators. Gold recovery in the gravity circuit varies between 15 and 20%, with gravity concentrate leached daily in an Acacia intensive leach reactor. Cyclone overflow, at a target P80 of 65 microns, flows to the flotation plant where the gold bearing sulfide minerals, mainly pyrrhotite and arsenopyrite, are recovered to concentrate with a mass pull of about 5%. The flotation concentrate, typically containing between 80 and 120 g/t of gold, is thickened and finely ground using a 1500 kW Isa Mill. The finely ground concentrate is diluted, to generate a slurry with about 32% solids by weight, before feeding the leach plant. Initially the concentrate slurry is pre-treated with oxygen and lead nitrate, to passivate the sulphide minerals before cyanide is added for gold dissolution. Gold is recovered from the leached slurry using carbon-in-pulp (CIP). The flotation tailings are also thickened and gold is recovered in a dedicated leach-CIP plant."

Jan 1, 2017

By Z. Gostynski

The paper is a historical cross-section through a 28-year period of operation of the direct-to-blister Flash Smelting Furnace in the KGHM Glogów Copper Plant. It presents the origin of the furnace as well as the path of numerous changes and modifications both in technology and process introduced in the furnace in response to the production and cost-reduction challenges. The authors provide justification of the statement that continuous improvement of the "Polish" Flash Smelting Furnace has ranked it among the most modem smelting units in the world.

Jan 1, 2007