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By J. S. Laskowski

Anisotropic minerals are important constituents of many ores. This group includes both valuable minerals (e.g., molybdenite in Cu-Mo ores) as well as gangue minerals (e.g., talc in platinumbearing sulphide ores in South Africa, graphite in Cu-Ni sulphide ores in Canada, chrysotile in Ni sulphide ores in Australia, and clay minerals in all types of ores). Aqueous suspensions of anisotropic minerals exhibit different properties than suspensions of isotropic minerals. The presence of anisotropic minerals in flotation circuits affects the flotation process.

Jan 1, 2012

By Charles Kingsley

THE PRESIDENT (DR. C. B. KINGSTON, member C.l.M.M.) expressed regret that neither of the authors of the paper was able to be present to submit the paper in person. In their absence, it would be introduced formally from the Chair. It was a clear, straightforward account of a fine piece of shaft sinking, cleverly conceived and boldly executed. He referred briefly to the distribution and nature of the Dome ore-bodies and stated that, for both the miner and the metallurgist, the mine had provided a wide range of problems of unusual interest. Discussion on the paper was then invited. MR. THOMAS PRYOR said the paper was most opportune, because the subject of internal shafts did not appear to be fully treated in current mining literature. Many members were not familiar with Canadian gold deposits and it would be of interest if the authors could give a brief description of the location of the ere deposits of the Dome mine. This information would doubtless explain why a new internal shaft was needed in a position which required such an exceptionally long cross-cut to connect it to the main hoisting shaft to surface. It would also add to the value of the paper if the authors would give some idea of the duty expected of the new shaft in terms of tons of rock hoisted and of trips engaged in the transport of men and materials, and it would be helpful if figures could be given of the total capital cost of the hoists and subsidiary excavations at the shaft top, and of the cost per foot for sinking and lining the shaft below the collar. Turning to details of the paper, one was favourably impressed by the care given to the provision of a good travelling way for men in the main cross-cut, as shown in Figure 1. It was by no means always that one could walk in comfort and safety in a working where there was a 20-in. ventilating pipe in the roof.

Jan 1, 1939

By Gustavo Angeloci

Artisanal mining is a rudimentary activity that today attracts over 30 million people in virtually all developing countries around the world. As the price of gold has steadily increased over the past decade, 15 million people have become involved in extracting this metal in 55 countries. Individuals have switched to mining from primary industrial sectors such as agriculture to increase their income. These workers generally have little capital, low education levels, and no previous experience in mining. Together with a lack of technical support from governments, these factors lead to disorganized and informal mining activities that generate environmental and social chaos. The absence of technical knowledge and capital has caused a proliferation of Gold Ore Processing Centres (GOPCs) around the world established by local entrepreneurs, who provide a way for miners to process their ores using amalgamation for a fee that is relatively low to non-existent. Gold recovery by the independent miners rarely exceeds 30 % and gold-rich tailings are left at GOPC facilities as a form of payment. GOPCs recover around 90 % of the remaining gold using cyanidation, flotation, and amalgamation, without any compensation paid to the miners. In processing these mercury (Hg)-contaminated tailings, Hg cyanide complexes are produced that are dumped into aquatic environments, leading to rapid bioaccumulation of Hg by fish. In the town of Portovelo, Ecuador, the establishment of partnerships between GOPC entrepreneurs and artisanal miners has proven to be successful in forming legal small-mining companies to create more equity and reduce pollution. About 108 GOPCs operate in Portovelo-Zaruma, with 40 % of these still working illegally without proper regulation and permitting. Over 20 % of these GOPCs continue to use grinding, concentrating and amalgamating of the gold, with 58 % performing cyanidation of tailings and/or gravity concentrates, and 15 % combining flotation with cyanidation. About 94 % of the GOPCs concentrate the ore prior to applying amalgamation, which significantly reduces Hg emissions to the environment. Incorporating flotation has given the operators increased skills in mineral recovery, with the side benefit of producing a copper concentrate as added value. Despite these innovations, mineral recovery is still inefficient, and waste management is a major challenge in creating true sustainability in this sector (technical efficiency together with social and environmental responsibilities). Further organization, training and capacity-building are needed. The principles of Lean Manufacturing Methods ("Just in Time" production and "Automation") are suggested as possible techniques to assist small GOPCs to become sustainable. In this concept, a larger mining company can become associated with artisanal miners in a partnership to provide training and investment for exploitation of small deposits that would be infeasible as a single large operation. As well, an International Training Centre for Artisanal Miners (ITCAM) is being established in Portovelo with collaboration of the Government of Ecuador to further enhance and upgrade mining activities in this region. ITCAM will provide artisanal miners with technical, business and environmental training to become responsible small-scale miners. In building this new capacity, ITCAM intends to create an atmosphere of trust to attract private and corporate investors to become partners with artisanal miners.

Aug 1, 2013

By M. Abumiya, N. Onodera

"The synthesis of large scorodite particles in non-ferrous metallurgical industries usually requires a high-cost operation involving heating and high-pressure autoclaving. To overcome these obstacles, an atmospheric-pressure process for scorodite synthesis (DMSP®) was developed, in which ferrous ions were oxidized by oxygen gas in the presence of pentavalent arsenic ions. This process gives scorodite of good crystallinity with particle sizes as large as 15-20 µm. The solutions used for scorodite synthesis in the DMSP® are prepared from various residues containing arsenic from non-ferrous smelters. The solutions may be contaminated with Cu, Sb, and Bi, for example, and therefore the effects of such impurities on the formation of crystalline scorodite need to be investigated. In this study, the effects of Cu, Sb, and Bi contaminants on the formation behaviors of scorodite particles in the DMSP® were investigated systematically.INTRODUCTIONThe synthesis of crystalline scorodite (FeAsO4·2H2O) is a suitable method for arsenic (As) stabilization and storage of As-containing by-products such as flue gas dusts in non-ferrous smelters. It is expected that the formation of large, highly-crystalline scorodite particles would be an ideal method for avoiding the release of arsenic to the environment. Generally, autoclave methods under pressurized oxidation conditions at temperatures above 100°C have been used for the formation of arsenic minerals such as scorodite. However, the autoclave method requires sealed vessels that are resistant to high pressure, heat and acids. This process is also unfavorable on account of the high construction expenses, and high running costs as a result of vapor heat loss. Processes for synthesizing scorodite under atmospheric conditions at temperatures below 100°C which do not need an autoclave have therefore been extensively investigated (Demopoulos, Droppert, & VanWeert, 1994; Demopoulos, 1996; Demopoulos, Lagno, Wang, & Singhania, 2003; Droppert, Demopoulos, & Harris, 1996; Filippou & Demopoulos, 1997).Recently, Fujita et al. (Fujita, Taguchi, Abumiya, Matsumoto, Shibata, & Nakamura, 2008a, 2008b, 2009; Fujita, Taguchi, Kubo, Shibata, & Nakamura, 2009; Fujita, Taguchi, Shibata, & Nakamura, 2009) developed a new method for producing large scorodite crystalline particles with improved filtration and washability properties at normal atmospheric pressure and temperatures below 100°C. In the new method, oxygen gas (O2) is blown into solutions containing a high concentration of arsenic ions (As(V)) and ferrous ions (Fe(II)). The Fe(II) ions were subsequently oxidized to ferric ions (Fe(III)), resulting in the formation of large scorodite particles. High supersaturation of solutes such as Fe(III) will result in excessive nucleation, and the formation of poorly crystalline phases. The scorodite formation must therefore be conducted in a manner that avoids the critical supersaturation level being exceeded. It is supposed that the oxidation of Fe(II) to Fe(III) by O2 gas in the new method suppressed the supersaturation of Fe(III) during scorodite formation. The low Fe(III) supersaturation resulted in formations of highly crystalline scorodite particles of size of around 20 µm. In June 2008, based on the developed process described above, DOWA began experiments to verify the industrial capability of a plant with a capacity of 30 MT/month of As. It was successfully proven that it is possible to produce crystalline scorodite industrially on a commercial scale. This process was named and trademarked as DMSP® (Kubo, Abumiya, & Matsumoto, 2010)."

Jan 1, 2012

By J. C. White

"This paper was prepared for and presented at a lecture series on ""Materials Randling"" at McGill University. The development of trackless mining at Gaspe Copper Mines, Limited is described, showing the changes in mining method and the part played by the mobile equipment in the evolution of this highly mechanized underground operation. Comparisons of loading and hauling machines are given and an attempt is made to predict some possible future developments.INTRODUCTIONTHE PROPERTY OF GASPE COPPER MINES LIMITED is located in the Gaspe Peninsula of the Province of Quebec, 60 miles west of the village of Gaspe and 25 miles south of the St. Lawrence River. The original discovery of low-grade ore was made at Copper Mountain in 1921. Subsequent exploration revealed the richer Needle Mountain orebodies, and eventually in 1951 the decision was made by Noranda Mines to build the mining, concentrating and smelting complex (Figure 1). Construction and development of the mine was commenced in 1952 and production started in 1955."

Jan 1, 1968

By I. A. Tinto

"Labrador City is located in the southwestern portion of Newfoundland-Labrador, approximately 965 kilometers north-east of Montreal. The mine and beneficiation complex of the Iron Ore Company of Canada, known as the Carol Project, is situated 535 metres above sea level in a climatic region characterized by cold winters and short, cool summers.HistoryThe Iron Ore Company of Canada commenced work in the area in 19 4 9' however, it was not until 1958 that the decision was made to proceed with mining operations. The ore body consists of Specular Hematite (Fe203) and Magnetite (Fe304) with small quantities of Limonite and Geothite. The average grade of the ore bodies is 39% iron.The mining facilities, crushing plant, and concentrator were in operation by the early part of 1962. In the summer of 1961, a decision was made to build a pelletizing plant adjacent to the concentrator. This plant was designed, erected and placed in operation during 1962 and the first half of 1963. Since the completion of the pelletizing plant, additional expansions to both the pellet plant and concentrator have taken place in 1967 and 1973. Today, the Carol Project has the capacity to produce 20 million tonnes of concentrate from which 10.5 million tonnes of pellets can be produced.The period 1980-85 spans a period of energy crisis, world-wide recession, and a consequent re-structuring of the North American steel industry as it struggles to survive in an arena of excess world steel making capacity, government subsidized industries, and the increasing competition from overseas and from developing countries.The media headlines over the past few years echo the woes of the industry and the strategy plans for survival of the fittest. Today's buzz words are foreign competition, steel import quotas, joint ventures, employee participation, work rules, quality, productivity, and state of the art technology."

Jan 1, 1986

By C. T. Harper, B. J. Fryer, R. P. Taylor

"IntroductionThe Maurice Bay deposit is one of a number of uranium deposits that have been found in recent years in the Athabasca Basin of northern Saskatchewan (Tremblay, 1982). This deposit, along with the others, belongs to the unconformity type deposits (Beck, 1977). They are, for the most part, polymetallic, being characterized by a suite of metals which include U, Ni, Co, Cu, Pb, Zn, Mn, V, Ag, Au, Pt-group elements, S, As, Bi, Se, Te, and Mo, some of which, besides U, are present in economic concentrations (Amok, 1974; Ruzicka, 1975; Tapaninen, 1976; Hoeve and Sibbald, 1978; Dahlkamp, 1978). The Maurice Bay deposit was known to be a small low grade deposit in which the ore was essentially monomineralic, consisting mainly of pitchblende (Harper, 1978). However, the occurrence of trace amounts of some of the elements common in the larger polymetallic ore bodies (e.g. Key Lake, Cluff Lake D) was anticipated. Thus a lithogeochemical sampling project was undertaken in 1979 across part of the Maurice Bay deposit (Harper, 1979). Major oxides (SiO2, Al2O3, FeO, Fe2O, MgO, CaO, K2O, Na2O, MnO, P2O5, and TiO2) and a group of the most common trace metals (U, Ni, Co, Cu, Pb, As, Au, V, and Se) were analyzed to determine whether any elemental patterns (halos or depletions) could be detected which would reduce the number of pathfinder elements needed for exploration purposes. In addition to the above metals, Th was also checked because some conglomerate strata in the Maurice Bay area are known to be thorium-enriched (Harper, 1978). Only the trace metal distributions will be discussed in detail in this report.General GeologyThe Maurice Bay area is underlain by three major groups of rocks, the White Lake metamorphic complex, an unnamed granodiorite complex, and the Athabasca Group, described previously (Fig. 1; Harper, 1979). Table 1 summarizes the stratigraphic features as deduced by geological mapping and the examination of drill cores."

Jan 1, 1986

By F. Vahdatikhaki

Simulation techniques have offered significant boosts toward a cost-and-time-optimized planning of construction projects by enabling project managers to effectively comprehend the behavior of projects. Using historic data from projects of like nature, simulation considers uncertainties involved in a project through accommodating the stochastic modeling parameters. However, the heavy reliance on the statistical data and not taking into account the context-specific features of the project cause the degradation in the realism and accuracy of the simulation models. Similarly, the extent to which a historic pattern could be retrofitted to new projects will decrease in line with the growing uniqueness of the projects and the novelty of construction methods. Furthermore, the existing real-time simulation frameworks are not capable of distinguishing the transient environmental changes, with minimal long-term impacts on the productivity, from the influential changes that will greatly impact an operation. In addition, existing simulation tools are devoid of location awareness, resulting in the inability to consider safety threats in their representation of the project. To address these issues, this research proposes a framework based on the integration of new tracking technologies used in Automated Machine Guidance (AMG) with simulation-driven 4D modeling methods. The proposed framework automates the adjustment of the simulation model based on the updated data from the site, and thus transforms simulation from a predictive tool used at the planning phase to a proactive monitoring platform usable throughout the planning and construction phases. A prototype is developed to test and demonstrate the effectiveness of the proposed approach.

Aug 1, 2013

By E. B. Wilson

"Although the Operations Research technique of Reliability Theory has been applied with marked success in many fields, including the Apollo spaceship programs, the concept of reliability has not been generally adopted in mining and other heavy industries. Of course, reliability, or the probability that a system will be able to operate without a failure for a given interval of time, does not require the same emphasis in mining as in the aerospace industries. Nevertheless, certain aspects of Reliability Theory can be followed advantageously. For example, reliability calculations can determine the best time to overhaul and whether to retain stand-by units.The usefulness of the pseudo-operations research technique known as Replacement Theory is more readily re-cognized by the maintenance engineers in mining and other heavy industries. One of the least complex models enables the optimum Lifetime of an asset to be determined."

Jan 1, 1970

By L. M. Pidgeon

Introduction The production of magnesium by direct reduction of the oxide has far passed the experimental stage and was responsible for 30 per cent of the recent wartime production of 246,000 tons per annum. This paper describes the small-scale experiments which culminated in a number of the wartime plants. The paper traces the author's early experiments on various direct reduction reactions leading to his choice of the ferrosilicon reduction of dolomite and the realization that this reaction would proceed at a satisfactory rate at temperatures obtainable in metal apparatus. MgO has a standard heat of formation of 146,100 cal. and is therefore one of the most difficult oxides to reduce. However, if advantage is taken of the relative volatility of magnesium metal, thermally unfavourable reactions may be utilized. In reaction MgO + X = XO+ Mg . . . . . . . . . . . . . (1) the removal of Mg as a gas at high temperatures displaces the equilibrium to the right in the face of the unfavourable thermo-chemistry which is inevitable with any X other than calcium metal. If X is carbon, not only is the reaction highly endothermic, but CO is gaseous. A temperature of l,864°C. is required to produce a pressure of one atmosphere of Mg. Between l,900°C. and perhaps 400°C., the back reaction takes place readily and special shock cooling devices are required to recover magnesium from the gaseous mixture. This reaction does not lend itself to small-scale experiments and was not examined by the author. If, in reaction, carbon is replaced by a relatively pan-volatile metal, the oxide of which is also non-volatile and possesses a fairly high heat of formation, a reduction reaction is offered which is free from the difficulties associated with carbon. The typical case of silicon will serve as an example: 2MgO + Si = SiO2 + 2Mg (g) . . . . . . . . . . . . . . . . . . . . . . (2) At temperatures above l,000°C., a positive pressure of magnesium will exist over the system. Removal of the magnesium vapour will displace the reaction to the right in the face .of an unfavourable thermal balance. Since magnesium is the only volatile component at this temperature, it may be evolved and condensed, using attractively simple distillation technique.

Jan 1, 1946

By R. J. T. Charles

Introduction An apparatus that will measure the surface area of a few of the simple minerals with a high degree of accuracy has been described by J. W. Bell (1). His apparatus consisted essentially of a photometric device that would measure the turbidity of fine particle suspensions. Turbidity, in this case, was considered as a function of surface area. Bell's method of surface area determination seemed to offer possibilities of extension and improvement to the point where it might approach a general method of particle size measurement. Theoretical and Practical Considerations of the Photometric Method In order to illustrate how turbidity may be considered as a function of average particle size, and to indicate the type of results expected from a photometric method of particle size measurement involving turbidity, the following theory may be hypothecated. If a number of particles, considered as spheres of uniform diameter, are placed at random in the path of a beam of light, the following expression, which will give the change in light intensity as a function of the diameter of the particles, the specific gravity of the material, and the weight involved, can be formulated from the Beer-Lambert Law:

Jan 1, 1951

By J. Ambrose, R. W. Zimmerman

"Shales are highly anisotropic in their mechanical behavior. The strength ( ??1) of anisotropic shales depends not only on the magnitude of the other two principal stresses ( ??2, ??3), but also on the bedding plane orientations (?) relative to the principal stresses. In this study, the role of the intermediate stress ( ??2) on the strength of shale is evaluated using new data from triaxial compression and extension tests. To understand the failure behavior of shales, we have carried out triaxial compression tests ( ??1 > ??2 = ??3) on two organic rich mudstones, at different confining stresses and loading angles. We first fit the triaxial compression data with Jaeger’s plane-of-weakness model, and find that the model is able to represent the strength behavior of anisotropic shales reasonably well. We then carried out five triaxial extension tests ( ??1 = ??2 > ??3) for a high strength-anisotropy shale, and two extension tests for a low strength-anisotropy shale. Results from the compression and extension tests for failure along the weak plane shows that the role of ??2 is not significant for weak plane failure. However, for the low strength-anisotropy shale, the failure strength of the intact rock (i.e., at ??= 0o and 90o) for compression and extension tests were significantly different. This indicates that for intact rock failure, the role of ??2 is important and cannot be ignored.INTRODUCTIONFor many years, various researchers have studied the roles of ??2 for failure of isotropic rocks. (Mogi, 1967 and 2007; Colmenares and Zoback, 2002; Al-Ajmi and Zimmerman, 2005 and 2006; Haimson, 2009; Ma and Haimson, 2012). The findings from these studies show that the effect of ??2 on the strength of isotropic rocks is generally significant, and cannot be ignored.Since the role of ??2 in the failure of isotropic rocks was recognized, other researchers attempted to extend some of these isotropic failure criteria to anisotropic rocks, but with limited success (e.g., Tiwari & Rao, 2007; Singh et al., 1998; Zhang and Zhu, 2007; Pei, 2008). Smith and Cheatham (1980), on the other hand, conducted true-triaxial experiments on the Green River Shale and used a J2-I1 type relationship to predict the strength behavior, but without considering the effect of the three-dimensional orientation of the weak plane on strength. Therefore, unlike for the case of isotropic rocks, additional studies need to be done to determine the role of 2 on the failure of anisotropic rocks."

Jan 1, 2015

By I-H. Jung, J. Kim

"Mg alloys are extensively used as light structural materials in modern industry. Mn and RE (rareearth) metals are effectively used as alloying elements to enhance the properties of Mg alloys. Therefore, the thermodynamic database of those alloys is important in the Mg alloy design and processing. Critical evaluation and optimization of all available literature data for the Mn-RE systems were conducted to obtain reliable thermodynamic functions. The Mn-RE systems shows systematic changes in the phase diagrams and thermodynamic properties with increasing atomic number in the lanthanide series. This systematic approach for all RE elements allows to resolve inconsistencies in the available experimental data. INTRODUCTIONRare Earth (RE) metals are widely used in many industrial fields including permanent magnet, electronic materials and structural materials. As a small addition of RE can enhance magnetic, electronic, optical and mechanical properties of numerous materials, the usage of the RE is still expanding regardless of the strategic control of their supply.Magnesium alloys are getting great scientific and industrial attention as the lightest structural materials. One of the drawbacks of Mg alloys is their poor formability at room temperature due to the limited slip system with hcp crystal structure. Recently, several studies (Farzadfar et al., 2011; Sandloebes et al., 2010; Stanford, 2010; Stanford et al., 2008; Yan et al., 2010) show that the additions of small amounts of RE can considerably enhance the ductility of Mg alloys. Therefore, a lot of research on Mg-RE alloys is undergoing to clarify the role of RE on the enhanced deformation mechanism and to find out the most optimum Mg alloy compositions. In order to respond to the need of Mg-RE alloy development, a large thermodynamic database for Mg alloys containing RE has been developed with critical systematic analysis and optimization of the entire RE series data. This includes the thermodynamic database of the Mg-RE (Kang et al., 2009), Mg-RE-RE (Kang et al., 2009), Mg-Al-RE (Jin et al., 2011; Jin et al., 2010), Mg-Zn-RE and Mg-Mn-RE systems."

Jan 1, 2012

By K. Parameswaran

This paper builds on presentations made at the Conference of Metallurgists (COM) 2015, COM 2017 and Extraction 2018 and associated papers published in the respective conference proceedings. Based on the classic Brundtland Commission definition of sustainable development as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs,” the paper describes how metal mining can be compatible with sustainable development and how sustainability considerations have been applied in the primary copper industry, using several examples of sustainable mining practices from ASARCO LLC operations. Finally, the paper discusses how these considerations might be used in the future by discussing the need for developing a sustainable development strategy and how this strategy can be aligned with the United Nations Sustainable Development Goals. INTRODUCTION The primary copper industry comprises: mining (also referred to as “extraction”); mineral processing (also referred to as “beneficiation, “milling” or “concentration,”) which includes leaching, solvent extraction (SX), crushing, grinding, froth and flotation operations; and metallurgical processing which includes smelting and converting; refining, which includes fire-refining or anode refining and electro-refining; and electrowinning (EW). There are two routes for producing refined copper: hydrometallurgical and pyrometallurgical. The hydrometallurgical route comprises mining (open-pit and underground), mineral processing (crushing and grinding — for heap leaching only; leaching and SX) and metallurgical processing (EW). The pyrometallurgical route involves mining, mineral processing (crushing, grinding and froth flotation) and metallurgical processing (smelting, fire refining and electro- refining). The primary copper industry is capital, water, resource and energy intensive with the potential for significant environmental impacts, if the environmental aspects are not properly managed. ASARCO LLC (Asarco) was organized in 1899 as the American Smelting And Refining Company. Originally a consolidation of several lead-silver smelting companies, it evolved over the years into an integrated producer of primary non-ferrous metals, including copper, lead and zinc and associated co-products. Grupo México, S.A.B. de C.V (Grupo México) acquired Asarco in 1999. Today, Asarco is a vertically integrated producer of primary refined copper and associated co-products such as gold, silver, selenium and tellurium. Asarco operates three open-pit mines and mills, two leach, SX-EW plants, a copper smelter in Arizona and a copper electrolytic refinery in Texas.

Jan 1, 2019

By Ray Mason, Damien Label, Howard Bernier, Kevin McDermott, Kevin Coombs

"GeneralWabush Mines is an unincorporated joint venture of seven steel companies and Pickands Mather & Co. The mining and concentrating facilities are located in southwestern Labrador and the pelletizing and shiploading facilities are at Pointe Noire, 200 miles south, near the town of Sept-lies.The operation is based on a 5 ½ sq. mi. specular hematite deposit with a reserve of 375 million tons of concentrate. Annual production capacity is rated at 6 million tons of pellets per year. The final upgrading process utilizes high-tension separation of silica following wet autogenous grinding, spiral gravity separation and fluo-solids drying. The concentrate is railed in closed cars to Pointe Noire. The concentrate is reground dry and pelletized on Dravo Lurgi travelling grate machines to produce an oxide pellet with 65.5% Fe, 3.0% Si02, 1.95% Mn and 93.5% Tumble Index.HistoryPlant operations commenced in 1965 with a concentrator capacity of 5.3 million tons per year and a pelletizing capacity of 4.8 million tons per year. The original facilities for classifying the crude ore into fine and coarse fractions for storage purposes before reblending as autogenous mill feed were found to be unnecessary and were by-passed after plant startup. Capacity of the operation was increased to 6.0 million tons of pellets per year in 1968. This increased capacity required the installation of an additional160 cleaner spirals in the ore dressing plant, a new 5000 hp ball mill, three balling circuits and increased cooling air capacity in the pellet plant.In 1970, the regrind circuit in the pellet plant was converted to dry grinding and a significant reduction in grinding media consumption and maintenance costs was realized. A ninth grinding mill of 5000 hp capacity was installed to compensate for the reduced capacity in going from wet to dry grinding."

Jan 1, 2000

By Courtney E. Cleveland

THE gold deposits of the Pioneer and Bralorne mines, in the Bridge River district of British Columbia, are closely associated with a long, narrow intrusive body of extremely variable composition, outcropping on the northeast side of Cadwallader creek and lying almost entirely within the property boundaries of the two companies. Other masses of the same type of intrusive rock are found in the district, more or less along the line of the main axis of the Pioneer-Bralorne in trusive, and have associated with them variable amounts of gold-quartz mineralization (Figure 1). The ore deposits of the district have been the subject of investigation by officers of the Geological Survey of Canada at various times during the past 25 years, and articles on the geology and mines of the district have been published by various individuals in technical journals. A list of the more important re-ports follows: SELECTED BIBLIOGRAPHY

Jan 1, 1938

By A. W. Jolliffe

AEROPROSPECTING may be defined as the application of the air view to the search for mineral deposits. The term is suggested as a preferable alternative to either aerial prospecting (which may be confused with areal prospecting) or air prospecting. The air view may be obtained by visual observation from an aircraft or by examination of air photographs; each has its particular advantages and disadvantages. Aeroprospecting should be regarded only as an aid to, and not as a substitute for, accepted prospecting methods ( l ). The Precambrian region north of Great Slave lake consists of two well defined physiographic units, a feature first noted by J. T. Wilson (2). The boundary between these lies close to the north shore of the east arm of the lake and extends northwesterly near Spencer, Beniah, Carp, and Ghost lakes (Figure 1). South and west of this line, exposed bed-rock makes up the greater part of the land area; eskers are very rare, and overburden is largely limited to rock-walled valleys and depressions. North and east of the line, outcrops are rare or absent, eskers are abundant, and most of the surface consists of drumlin-like drift hills, elongated parallel to the direction of ice movement (Figure 2). Where this boundary passes through the area shown in Figure 1, it lies near the 1,200-foot contour and may mark the maximum extent of the lake or sea arm present in this vicinity toward the end of the Pleistocene period. For convenience, the first area may be called the 'bed-rock belt' and the other the 'drift belt'.

Jan 1, 1945

By Warren A. Sheaffer

THE chief uses for copper are as a conductor of electricity and as the chief component in brasses and bronzes. For such uses, the copper must be of very high purity. H the impurities are zinc, iron, lead, arsenic, or antimony, they can be removed to a great extent by fire-refining. H, however, gold, silver, nickel, or cobalt are present, electrolytic refining is necessary. Electrolytic refining must be preceded by fire-refining and hence all impure copper must be fire-refined. The electrolytic refining of copper is most efficiently carried on when the impurities in the anodes are at a minimum. Some of the impurities tend to deposit with the copper at the cathode, while others remain in solution, decreasing the conductivity of the electrolyte and thus increasing the voltage necessary for refining. Since these dissolved impurities must be removed by continuous purifications, the amount of impurity in the anode copper should be reduced by furnace refining to some predetermined limit. Anode furnace operation aims to reduce these impurities to a minimum beyond which the cost of further furnace refining would exceed that of removing the remaining small amounts of impurities from the electrolyte. The anodes should have a fine-grain internal structure because any pieces of metal becoming detached from the anode during the electrolytic refining are inconvenient to remove from the cells and may cause short-circuits. Impurities tend to disrupt such a structure and thus form zones of weakness during corrosion. When the impurities are reduced to a satisfactory mini-mum, the anode, due to having a fine-grain structure, will corrode uniformly over the entire surface area exposed to the electrolyte. Oxides of the impurities may be volatile, in which case they pass off as flue gases, or they may form viscous slags having a lower specific gravity than molten copper, thus permitting their removal by skimming. Some impurities can be oxidized by introducing air into the bath. Due to the large solubility of oxygen in molten copper, oxygen is distributed uniformly throughout the bath and thus comes into intimate contact with all impurities. The oxides which are insoluble in molten. copper are removed either as flue gases or as slag.

Jan 1, 1942

By Xiaoqiong Wang, Daobing Wang, Fanbao Meng, Jianbo Wang, Hongkui Ge

"Shale gas has become an important unconventional oil and gas resources. Its effective development relies on comprehensive and accurate understanding of shale gas reservoirs. Rock mechanical properties is one of the important components of reservoir evaluation. Two adjacent black shale samples, which are cored from the depth of 1145 meters in Chongqing, southwest China, are subjected to acoustic emission(AE) test under uniaxial stress and compared with coarse grained granite. The results of synchronous AE, stress-strain and ultrasonic velocity experiments show that shale has weak anisotropy. Compared with granite sample, two shale samples are similar, but their strength, velocity and brittleness are quite different, indicating that shale has strong microscopic heterogeneity. TOC, XRD, SEM microstructure analysis show that total organic content, mineral composition and natural fractures are the main impacting factors for mechanical heterogeneity. INTRODUCTIONShale gas is a typical low-grade marginal resource, which is characterized by ultra-low matrix permeability and small single well control volume. In order to enable commerical development, complex hydraulic-fracture networks must be created in the shale to allow gas to escape from the micro/nano-pores and natural fractures where it is trapped in the rock (C. Clark et al.,2013; Ge et al., 2013). The development of shale gas requires accurate evaluation methodologies to evaluate shale reservoir properties and predict production. (Jarvie et al., 2007). Rock mechanical properties are an important part of the reservoir evaluation. It is significant for efficient drilling, completion and hydraulic fracturing to understand mechanical behavior of shale gas play (John, 2011; Wei, 2013).Rock mechanical properties mainly include heterogeneity, anisotropy, brittleness and acoustic emission activity (Lockner et al., 1992; Jerome et al., 2009; He et al., 2010; Liang et al., 2012). Shale mechanical properties are evaluated from laboratory tests following a complex workflow that covers tasks from sampling to testing (Md. Aminul Islam et al., 2013). It is common to include various experimental methods such as stress-strain curves, ultrasonic velocity and acoustic emission when evaluating the mechanical properties (Rao et al., 2006). Because of the presence of organic-rich matter, mineral composition orientation and natural fractures, shale tends to have strong anisotropy and heterogeneity (Deng et al., 2004; Wang et al., 2013; Hathon et al., 2013)."

Jan 1, 2015

By M. Jahazi, J. Gholipour

Design and manufacturing of parts using hydroforming process require knowledge about material behaviour and tribological effects during hydroforming. Lubrication is one of the key issues in successfully hydroform the tubes. A Ni-based super alloy tube with 50.8 mm (2 inches) outer diameter and 0.9 mm (0.035 inches) thickness is considered for this research to study the effect of lubricants on the formability of the tubes. Hydroforming of a hollow compressor blade is considered for this project. A combination of press forming and hydroforming is employed to produce the part. LS-DYNA, an explicit dynamic finite element code, is used to model the experiments. Different lubricants are modeled using different coefficient of friction in the model. Predicted results for strain distribution at a critical section of the tube are extracted for each case to evaluate the effect of different lubricants on the process.

Jan 1, 2006