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By V. Falmagne

The mining sequence at Noranda?s Bell-Allard mine calls for two mining fronts retreating toward a central pillar known as the Retreat Zone between pyramids A and C. It is clear from numerical modelling and rock mass characterization that the induced stress level in the pillar will exceed the rock mass capacity. A mining plan was developed including the re-dimensioning of stopes in the Retreat Zone, additional ground support and instrumentation in order to ensure the safety of the workforce and to maximize ore recovery while minimizing production delays. The mining strategy consists in allowing the rock mass to fracture and fail progressively while maintaining control of the existing openings with the appropriate support. A systematic analysis of rockbursting and caving hazards was conducted for all accesses and stopes in order to plan ground support and instrumentation needs.

Apr 1, 2004

By G. A. Frame, J. G. Patterson

The 24,000-tpd Frood-Stobie mill grinding circuit operation and control are described. Changes implemented during the past three years to improve grinding efficiency and capacity are discussed.

Jan 1, 1971

By C. Barnett

"The mill at Noranda Mines Limited, Geco Division in Manitouwadge, Ontario went into production in 1957 treating 3,500 tons per day of copper, zinc, silver, lead ore. It was not until 1964, however, that the zinc concentrate drying plant was constructed. In 1970, milling capacity was increased from 4,000 to 5,000 tons per day. The zinc content of the ore is quite variable so that the tonnage of zinc concentrate dried varies from 200 to 650 tons per day.The drying plant was designed to dry 25 tons of zinc concentrate, dry basis, per hour from an initial moisture of 8.5% to a final moisture of 2%. Major components were selected so that capacity could be increased to 35 tons per hour with minor modifications.The rotary dryer is a Hardinge type ""XH-12"" with a diameter of 80"" and a length of 50 feet. The all welded construction shell is 1/2 inch thick mild steel plate with 3/4"" thick reinforcing bands under the tires arranged for operation at a slope of 1/2 inch to the foot. The 3/8"" x 12"" radial flights are welded to the shell. There are no flights in the last ten feet of the shell in order to reduce dusting. This unit is driven by a 50 HP motor through a Hamilton type CD250 double reduction helical gear speed reducer. The shell speed is 5.8 RPM.The standard Peabody horizontal air heater has a rated capacity of 10,000,000 B.T.U. 's/Hr. The combustion chamber is lined with high temperature refractory brick and is air cooled. The conical outlet section of the air heater is lined with insulating fire-brick. The burner is a type AT wide range mechanical atomizer fired by a type ""CR"" gas-electric ignitor.The Bunker ""C"" fuel is supplied by a Compower duplex pumping, heating and straining unit, including tank hotwell, Powertronic oil line heating system with a 550/24 volt transformer."

Jan 1, 1972

By E. Herrera, L. Mariscal

"Ilo Copper Smelter operates since 2007 with an ISASMELTTM furnace as a single smelting unit (1,200,000 tpy) associated with two Rotary Holding Furnaces for separation of matte and slag, and which directly produces a discard slag. Southern Peru continually has been improving the slag chemistry of its ISASMELTTM furnace in order to reduce copper losses, given its big economic impact due to large slag mass generation. The present paper describes the influence of the CaO, Al2O3 and magnetite content in the slag of the ISASMELTTM furnace correlated with the SiO2/Fe ratio and its liquidus slag. Also it defines the best slag chemistry and operating practice in order to reduce the copper losses without compromise the bricks life of the furnace.INTRODUCTIONIlo Copper Smelter of Southern Peru (Grupo Mexico) is located on the southern coast of Peru, and treats mainly copper concentrates produced in its own mines (Toquepala and Cuajone).The modernized smelter was commissioned in 2007 and operates with an ISASMELT™ furnace as a single smelting unit (1,200,000 tpy), which is associated with two Rotary Holding Furnaces (RHF) for separation of matte and slag. This slag is directly sent to the dump. Figure 1 shows the smelter flow diagram.The ISASMELT™ process is a bath-smelting process using a single lance. The lance tip is immersed into a molten slag bath contained within the stationary, vertical, refractory-lined ISASMELT™ furnace. The injection of oxygen-enriched air, through the lance into the slag results in a highly turbulent molten bath. Feed material falling into the turbulent bath from above reacts rapidly, resulting in extremely high productivity for a relatively small bath volume."

Jan 1, 2012

By B. Yamamoto, D. Post, J. De Leon, A. Meike

"This paper describes the theory, design, building, and testing of the passive magnetic bearing stabilizing system which is the core of the passive magnetic bearing system. The stabilizing system is made up of two large magnetic disks opposing themselves with a stabilizing disk in the center which allows the system to self-locate in a null position without the need for external power sources or sensors. When outside forces act upon the stabilizer, the magnetic fields interact with the stabilizing plate to return the system to its null position. Collaboration between two industry leaders has allowed an actual prototype to be built and tested providing real data to prove out the theory.INTRODUCTIONMagnetic bearing/stabilizer systems have many advantages over conventional mechanical bearing systems. These include near-zero drag losses and no need for lubrication since the rotating elements make no mechanical contact with the stationary elements of the bearing system. However all magnetic bearing systems must contend with a constraint known as Earnshaw’s Theorem in the early 1800’s, this theorem asserts the impossibility of constructing a stable, non-contacting, electrostatic or magnetostatic levitation system using only fixed charges or fixed magnetic poles, such as those produced by permanent magnets. Because of the constraint imposed by Earnshaw’s Theorem virtually all present-day commercial magnetic bearing systems are of the “active” type. That is, they employ electromagnets that are powered by amplifiers the inputs to which come from sensors embedded in the bearing system. These sensors are a part of a feedback loop that operates to keep the levitated rotating parts of the bearing stable and centered. The resulting complexity means that active magnetic bearings are expensive, require periodic maintenance, and continuously consume electrical power to energize their amplifiers and their electromagnets.Passive magnetic bearings are, of course, also subject to the constraints imposed by Earnshaw’s Theorem but they solve this problem in a straightforward and simple way, with only “passive” elements that take advantage of a loophole implicit in the derivation of Earnshaw’s Theorem. This loophole is that Earnshaw’s Theorem as derived applies only to static systems, i.e. an assembly of stationary permanent magnets arranged so as to levitate an object containing other permanent magnets. The theorem can be overcome if dynamic effects are taken into account. In active magnetic bearings the “dynamic effects” involve the afore-mentioned sensors, amplifiers, and electromagnets."

Jan 1, 2012

By M. Venkatraman

The limit of Hall - Petch relationship in ultra fine grained steels has been examined based on dislocation pile-up mechanism. When the grain size becomes small the dislocation multiplicity ceases resulting in very low work hardening rate in these materials. An approximate analysis of the theories of hardening indicates that H-P relation is obeyed up to 100nm. It appears that grain refinement is not the suggested approach to improve toughness as well as strength below a critical size.

Jan 1, 2004

By C. V. Corless

1. Introductory Some members may recall that at the Annual Meeting two years ago I read a paper, 'The Future of the Mining Industry in Canada." Discussing this large subject it was possible only to outline the facts and inferences leading to ?the conclusion that Canada is a country endowed with enormous mineral wealth, of which the fringes are yet scarcely touched. In the present paper, I wish to examine in somewhat fuller detail the evidence, both direct and inferential, concerning the mineral wealth of the greatest physical and geological feature of Canada-the Precambrian Shield. Many, if not most, of these facts are already familiar to you. But, since they will form the basis of the reasoning employed, they will be recalled for explicit reference. First, let us review very briefly the position and extent of the Shield. The area of the entire Shield is given in textbooks as 2,000,000 square miles, of which perhaps 10 or 12 per cent. is exposed in the south-easterly part of Canada's Arctic islands. The remainder occupies roughly two-thirds of the North-west Territory; the north-east corner of Alberta; one-third of Saskatchewan ;two-thirds of Manitoba; three-fourths of Ontario; and nearly ninety-five per cent. of Quebec.

Jan 1, 1924

By Andrew J. Troop

"VAUGHAN THOMPSON designed the Thompson retrievable diamond drill wedge and reaming assembly in 1948. Since 1950, the Hudson Bay Exploration and Development Company, Limited has used the method extensively. The wedge, setting tool, and reamer have been modified slightly since they were first introduced. In 1951, Mr. Thompson designed the Thompson arc cutter. The purpose of this tool is to decrease effectively the diameter of the arc cut, using standard drilling tools. This directional drilling device is usually employed when a branch hole is desired. The Thompson arc cutter has been used with success at Birch Lake, Saskatchewan, at the property of Cuprus Mines, Limited, Manitoba, and at Thompson Lake, Manitoba.UsesThe Thompson retrievable wedge provides a simple method for:(1) Re-drilling lost core sections(2) Re-sampling sections of old holes(3) By-passing lost tools Correcting the direction of a hole(4) Drilling a branch hole to obtain intersections at a higher elevation than the original holePrevious to the spring of 1951, the wedge was used only for the first four of these purposes. Recently it has been employed extensively for drilling branch holes."

Jan 1, 1953

By W A. Bardswich

The numerous factors associated with the prov1s1on of satisfactory air conditions in hot and humid Canadian mines are described. The main heat sources are auto-compression and the actual flow of heat from the rock. Temperatures reach 97°F at a depth of 8,100 feet. Various methods used in coping with high temperatures are described, including the use of ice stopes and heat exchangers. Moisture control, desirable air volumes and velocities, sizes of airways and methods of distribution are important considerations. A comparison of the temperatures, humidities and types of airways of two deep mines should prove useful in the design of future ventilation systems. Introduction OUTDOOR temperatures in northern Ontario vary from a low of around -40°F in winter to a high of about +90°F in summer. The average annual mean temperature over a 12-year period was +35°F, with a summer mean of 54 o and a winter mean of 16°. Because of low outdoor temperatures, a number of northern mines must heat fresh air for underground ventilation in winter; others, with high rock temperatures, are faced with a year-round cooling problem.

Jan 1, 1965

By Lex L. Udy

External-detonation-generated plasmas, highly ionized zones of reacting material ejected from the surface of detonating explosive charges, are shown to be the cause of channel desensitization, i.e., the self-quenching of a detonating explosive column loaded in a borehole with an air annulus between the explosive and the borehole wall. The effects of this phenomenon on several explosive compositions and types are demonstrated and discussed. The explosives tested include aluminum-sensitized and explosive-sensitized slurries, ANFO, liquid explosives and dynamites. Various techniques are described that can be used to reduce or eliminate the plasma effect.

Jan 1, 1979

By Victor F. Hollister

Elemental sulphur occurs as aformational sedimentary deposit in Upper Devonian Wabamun evaporites near Coronation, Alberta. The deposit developed in a stratigraphic jacies-change lrap; it is assumed that petroleum reacted with anhydrite to form sulphur, calcite, hydrogen sulphide and other reaction products. The deposit contains about 362,800 tonnes of sulphur and lies at a depth of 1200 m. The Coronation deposit is expected to be geologically typical of such other native sulphur deposits as may be found in Wabamun Group sediments. Widespread sour gas sulphur production f rom the Wabamun suggests the possibility that additional native sulphur deposits will ·be found.

Jan 1, 1984

By B. Haneman, J. A. Gorst, W. Slabbert

"The Bayer process involves the digestion of bauxite in caustic liquors at high temperature and pressure. Typically the digestion section of the plant involves the heating of liquors up to the digestion temperature followed by flashing of the digestion product to atmospheric pressure with the flashed steam used to pre-heat the incoming cold slurry. Despite the heat recovery, the digestion process is a high consumer of energy. The application of tube digestion technology in such plants has resulted in significant improvements in refinery energy efficiency with associated benefits of process simplification and refinery flow sheet capital cost reduction. This paper reviews the potential application of this technology to other metals within the non-ferrous industry.THE BAYER PROCESSA typical Bayer flow sheet is shown in Figure 1. The raw feed material bauxite (containing aluminium hydroxide as gibbsite Al(OH)3 and boehmite AlO(OH)) is digested in caustic liquors (caustic soda is the solvent) at high temperature and pressure. This process extracts the alumina and silica and any carbon present on the ore. The slurry is then flashed down to atmospheric condition allowing for heat recovery from the flashed vapour and producing slurry supersaturated in alumina.Following the digestion process the mud is removed via thickening and then pressure filtration to remove fine particulate and produce a clarified liquor with dissolved alumina in solution. The resulting pregnant liquor is then cooled allowing the alumina in solution to precipitate as aluminium trihydrate Al(OH)3. The precipitated hydrate is then filtered and washed and classified into fine and coarse fractions. The fine material is returned to the precipitation process as seed while the coarse fraction is calcined at high temperature to produce alumina. The filtrate from the filtration process (spent liquor) is then heated by the incoming pregnant liquor before being fed to an evaporation process which produced the strong caustic liquor required in the digestion process. Finally, the mud from the thickening process is washed to recover caustic and then fed to tailings ponds. The washer overflow is then mixed with the digester product to increase super-saturation."

Jan 1, 2012

By M. du Plessis, G. More O’Ferrall, A. Hartzenberg

"Lonmin Platinum has experienced several cases of large-scale hangingwall instabilities during the extraction of the Upper Group 2 Chromitite Layer (UG2) at a number of the Marikana operations along the Western Limb of the Bushveld Complex. These instabilities were all attributed to the presence and interaction of prominent geological features and highlighted that assumptions made in the design of the stable pillars and stable span were potentially overly simplistic in these areas. Investigations into the various case studies over the past ten years have resulted in the identification and classification of the rock mass characteristics of the geological structures causing the instabilities.In order to get a better understanding of these instabilities, it is important to understand the structural geology in general, and the sequence of events that led to the formation of the Bushveld Complex in particular. The tectonics involved in the formation of the various layers around the economic mineralized layers has been investigated, and the influence of these tectonic events on the stability of the UG2 stopes hypothesized.Following this investigation, the behaviour of the various layers in the hangingwall of the UG2 is better understood. This paper presents a description of the ground conditions being experienced in the underground stoping environment, the possible source of the associated structures and the resultant behavioural mechanism of these structures causing the rock mass instabilities."

Jan 1, 2015

By Louis Frost

"Dominion No. 17 Colliery, of the Dominion Coal Company, Limited, is located in the district of New Victoria, N.S., at the entrance to Sydney harbour.This Colliery was opened in 1882 to work a submarine area of the Harbour seam (see Figure 1). It was closed in 1921 and the mine, which has a make of water of approximately 250 gallons per minute, was allowed to fill.No. 18 Colliery, situated almost a mile to the east, was opened in 1938 to work the Phalen seam in this area with the intention, later, of driving a cross-measure tunnel to mine the section of the Harbour seam lying between No. 17 Colliery and the Princess Colliery of the Nova Scotia Steel and Coal Company, Limited.In 1945 it became necessary to open this area in the Harbour seam and a cross-measure tunnel was driven from the existing workings of No. 18 Colliery in the Phalen seam, which underlies the Harbour seam at a depth of 500 feet.The tunnel was started in 1946 and completed in 1948. The cost of opening this section, which contained only 6 1/2 million tons of coal, made imperative the recovery of all the available coal and precluded the maintenance of the large barriers that had been left in No. 17 Colliery for impounding the water, especially as the maintenance of these barriers would have meant the loss of 885,000 tons of coal, or 12.3 per cent of the whole tonnage available. Therefore, a study was made to determine the best means to dewater the 250 million gallons of water lying in the old No. 17 Colliery."

Jan 1, 1952

By G. Reuben Yourt

THIS paper is chiefly a description of the improvements in dust control chat have been brought about in the assay office grinding room at Wright-Hargreaves. The fume exhaust systems are briefly included because they also are important to the health of the employees. There are three chief factors which determine the efficiency of a dust control system: First, the amount of time and thought spent in designing it. Second, how close! y it is kept up to date with the growth of the plant-a system that is adequate for the number of machines operating when it is installed may fall short of fulfilling its purpose as the plant expands. Third, unless someone is held directly responsible, a system is likely to get out of repair and gradually lose its efficiency-this can easily be detected by regular dust surveys. In designing the present system at Wright-Hargreaves, the object kept in mind was to reduce the dust concentration of all operations to a safe limit, chat is, well under 300 particles per cubic centimecer of air. By doing this, a condition would be attained chat would make it possible to discontinue the use of respirators, which at best are not very comfortable and do not remove all of the hazardous fine-dust particles.

Jan 1, 1941

By R. R. Rogers

ABSTRACT The experiments described demonstrate that crude commercial lithium containing in the order of 0.5 per cent sodium can be refined, the resulting metal containing as low as 0.001 per cent sodium. During the process, the metal is vaporized and condensed at a gauge pressure of less than 0.04 micron. Considerable operating data and a detailed description of the experimental equipment are included. INTRODUCTION DUE TO THE unusual properties of lithium metal, its use is likely to increase considerably during the next few years (1, 2). This is of particular interest to Canadians because there are important deposits of lithium-containing minerals, especially spodumene, in Canada and it is hoped that lithium compounds and lithium metal will be produced from these deposits in the fairly near future. In order to assist in the development of this industry, the Mines Branch of the Department of Mines and Technical Surveys has initiated a programme of research in lithium metallurgy. In 1948, a paper (4) was published on methods of producing lithium metal and its alloys. Data on the corrosion resistance of some lithium alloys were included. In 1949, a paper (3) was published which showed that the addition of a small percentage of lithium to zinc anodes used for cathodic protection will improve their usefulness under certain circumstances.

Jan 1, 1951

By D. B. Dreisinger, D. G. Dixon, G. Nazari

"The kinetics of chalcopyrite leaching in acidic ferric/ferrous sulfate media under atmospheric conditions in the presence of pyrite has been investigated. It has been found that pyrite samples from different sources affect the rate of chalcopyrite leaching differently. A strong correlation between the amount of silver associated with the pyrite and its effectiveness has been noted. In this study, improvement of the catalytic properties of pyrite such that all pyrite samples accelerate the rate of copper extraction regardless of their sources is demonstrated, and a detailed discussion of the mechanisms involved in the process of chalcopyrite leaching in the presence of silverenhanced pyrite is presented. INTRODUCTIONIt is well known that chalcopyrite resists leaching in sulfate media. It has been proved that pyrite facilitates the leaching of chalcopyrite (Berry et al., 1978; Dixon et al., 2008; Mehta and Murr, 1983; Muñoz et al., 2008; Nowak et al., 1984, Tshilombo, 2004). Considering the catalytic effects of pyrite on accelerating the kinetics of chalcopyrite leaching, Dixon and Tshilombo (2005) have developed a new process, known as Galvanox™, which has several advantages over other hydrometallurgical processes. Galvanox™ runs under atmospheric conditions, so it requires only low-cost leaching tanks. The sulfur yield at this temperature is high (>95%) which leads to low oxygen consumption and low sulfuric acid generation. The operating temperature is below the melting point of sulfur which eliminates the use of surfactants. This process also does not require fine grinding. Reaction 1 shows the overall leaching reaction in the Galvanox™ process.CuFeS2 + O2 + 2 H2SO4 = CuSO4 + FeSO4 + 2 S0 + 2 H2O (1)Complete copper recovery from the Galvanox™ process can be achieved at a considerably higher rate than other atmospheric ferric sulfate leaching processes (Dixon et al., 2008). Recycling pyrite and recovering copper from tailings with the Galvanox™ process have also been evaluated in continuous pilot leaching campaigns (Dixon et al., 2007)."

Jan 1, 2012

By W. H. Fertl, S. J. Pirson

Well logging techniques, as used successfully in oil and gas exploration, can also be used to give a detailed evaluation of drill holes through industrial mineral deposits such as sulphur. This paper describes the logging tools used gives the theory behind the well-log interpretation and discusses the application of the method in sulphur-bearing limestone and m more complex sulphur deposits.

Jan 1, 1970

According to the principle of similarity, the physical and chemical configurations of a system can be defined by ratios of magnitudes within the system and do not de-pend on the size or nature of units of measurement. In the present work, the similarity principle was utilized in evaluating the reducibility of various iron ores in a rotary batch furnace under optimum operating conditions. It was then used successfully to extrapolate the results, first to the operation of a 20-ft. pilot-plant kiln and then to an industrial-size 80-ft. kiln. By means of this systematic analysis of kiln operation, it was possible to increase the production capacity of the kiln considerably. T HE kilns used by the Strategic-Udy process for the partial reduction of iron ores are, in most aspects, similar to conventional calcining kilns. Iron ore is fed continuously in the upper (feed) end of the kiln and, as the latter rotates

Jan 1, 1964

By J. Pontt

Gearless mill drives (GMD) offer high performance for torque and speed control for grinding mills and have been applied successfully in modern concentrators for wet grinding with mill diameters from 34 to 40-feet. It is considered a mature technology. However, recently, some large GMD?s have presented unexpected failures in stator and rotor subsystems. The phenomena involved in such failures has shown a complex nature and surprised users and manufacturers. The manifestation of such failures has been observed as mechanical damages to certain components of ring motors. This paper presents a discussion on the electromagnetic forces that can generate stresses in the electrical ring motor that can produce failures and outages. Guidelines for further research and contributions to improved reliability of GMD?s are proposed.

Jan 1, 2012