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By Lewis T. Wright

(Pittsburg Meeting, March, 1910.) I HAVE long been aware that ferruginous copper furnace slags if fused in the electric arc will yield metallic iron containing copper, and in order to confirm this knowledge, and to obtain further information of the behavior of such slags in the high temperature and reducing conditions of the electric furnace, a number of samples of slag were fused in an experimental electric furnace. The results obtained, given in Table I., show that a very large amount of metallic iron was produced, and that this iron carried with it practically all the copper, gold, and silver, and more than 50 per cent. of the sulphur, of the original slag. The metallic buttons formed in the electric furnace were clean, hard, but not brittle.

Mar 1, 1910

By Herbert Tomlinson

The United States Bureau of Mines has engaged in a study of the conditions under which coal mine accidents, resulting in the loss of life, limb, or time to the injured person, occur from falls of roof and coal. This publication is devoted to the results of a study conducted in the coal mines of the Book Cliffs and Wasatch Plateau coal fields of Utah. To show the necessity of this study, a statement of the fatalities that have occurred during the period 1928-1930, inclusive, in the bituminous mines of the United States and of Utah, is presented (Table 1), followed by a brief description of this Utah district, its coal beds and immediate roof, thickness of cover, dip of coal beds, methods of mining, supervision, roof testing and timbering for roof support, all of which are factors in any plan devised for preventing accidents from falls of roof and coal.

Jan 1, 1932

By Herbert Tomlinson

The United States Bureau of Mines has engaged in a study of the conditions under which coal mine accidents, resulting in the loss of life, limb, or time to the injured person, occur from falls of roof and coal. This publication is devoted to the results of a study conducted in the coal mines of the Book Cliffs and Wasatch Plateau coal fields of Utah. To show the necessity of this study, a statement of the fatalities that have occurred during the period 1928-1930, inclusive, in the bituminous mines of the United States and of Utah, is presented (Table 1), followed by a brief description of this Utah district, its coal beds and immediate roof, thickness of cover, dip of coal beds, methods of mining, supervision, roof testing and timbering for roof support, all of which are factors in any plan devised for preventing accidents from falls of roof and coal.

Jan 1, 1932

By M Dickie

During the 1980s and early 1990s low cost gold treatment plants were at the forefront of the Australian engineering and mineral processing business. This opportunity was the result of a high gold price and innovative design by emerging engineering companies in an expanding market. The low cost approach to gold plant design and project execution resulted in smaller and shorter life projects becoming viable and the multiplicity and fast track approach of the projects resulted in sharp learning curves. From the mid 1990s to the early 2000s the relatively low commodity prices and resultant reduction in minerals opportunities also resulted in innovative design in both small and large plants, albeit on a reduced scale. The innovation was associated with alleviating capital cost pressures for large capacity low-grade (eg NewcrestÆs Cadia) or small-scale (eg JubileeÆs Cosmos) projects to either improve NPV or to enable the project to be won and profitable in the competitive lump sum environment. Between 2004 and 2008 the engineering market became less competitive from an engineerÆs perspective due to the high demand for engineering services in a high price commodity market. The need for innovation remained but was driven overtly by shortages in water, power and personnel and long equipment lead times. This paper discusses some of the factors that contribute to the capital cost of a project and the scope for improving the likelihood of financing and increasing the project net present value (NPV). Case studies with recent large copper concentrator projects will be used to demonstrate how a value driven approach to project and plant layout can result in significant improvement in NPV.

Jan 1, 2009

By I. D. Nock, R. M. Parkin

Paper presented at a meeting on: Artificial intelligence in the minerals sector, held in Nottingham, UK, 20 April 1993 (original title: Knowledge-based condition monitoring of cone crushers). A large proportion of the electricity used by the quarrying industry is consumed in the comminution and sizing process. In most cases aggregate processing plants operate with minimum control features resulting in limited operational efficiency. Improved control is required to increase operational efficiency with concomitant savings associated with reduction in re-circulating load and improved resource utilisation. Development work has suggested that a combination of adaptive control and process condition monitoring could improve control of comminution plants. Many commercial process control and condition monitoring systems are available, but none were deemed suitable due to the domain specific characteristics of the application. An assessment of the particular characteristics of cone crushing concluded that the application was best suited to the use of small domain specific process control combined with bespoke condition monitoring. The processing power of the control system for the project is a function not of the academic requirement, but rather the economic and practical constraints imposed by the application. As a result of the constraints a high-end PC system has been designed in preference to a workstation. Within the research project work packages are sub-divided into novel wear sensor development, knowledge based control/condition monitoring and the investigation and mathematical modelling of the wear mechanisms inherent in cone crushing. Numerous strategies were considered to implement the control system outlined. The system currently under development is a modular design which utilises intelligent novel sensors to provide a variety of data inputs

Apr 1, 1994

By Paul Armstrong

THE first discovery of lead and zinc ore on Calumet island was made in 1893 by John Lawn, who then staked a portion of the property now owned by Calumet Mines, Limited. His discovery was developed by James and Calvin Russell, who are said to have shipped a few tons of sorted ore, averaging 39 per cent zinc, 13 per cent lead, and 11 oz. silver per ton. In 1898, the property was being operated by the Grand Calumet Mining Company, who mined and shipped, for treatment in a Belgian smelter, 1,100 tons of ore averaging 32 per cent zinc, 9 per cent lead, and an unreported content of gold and silver. After some indecisive exploration by an American syndicate in 1907, the property lay idle until1910, when the Calumet Metals Company-later reorganized as the Calumet Zinc and Lead Company-re-commenced exploration. After sinking an 85-foot shaft-the McDonald shaft-and doing a few hundred feet of drifting and cross-cutting, this Company, in 1912, erected a 150-ton daily capacity gravity-concentration plant, in which some 800 tons of ore, mined from the McDonald shaft and Bowie pit, were milled. Owing to very disappointing mill recoveries, the property was shut clown and-after several years of idleness-in? 1916 the mill and mining plant were destroyed by fire and the Company went into bankruptcy. In 1918, an unknown operator shipped to an Omaha, Nebraska, smelter 22 tons of ore, probably sorted from the dumps of the Ste. Anne shaft and Galena pits, averaging 44 percent lead, and 0.26 oz. gold and 61 oz. silver per ton. The British Metals Corporation (Canada), Limited, in 1926, optioned the property. They unwatered the McDonald shaft and, after doing an additional 300 feet of cross-cutting and drifting on the 85-ft. level, estimated there were some 33,000 tons of ore between this level and the surface. Surface exploration, including trenching, on other showings on the property gave discouraging results and the option was dropped.

Jan 1, 1941

By Alexander May

The U.S. Bureau of Mines investigated the application of oxidation-reduction potential (ORP) and pH measurements to environmental studies of mining and mineral processing wastes, and developed a computer program to estimate the concentrations of species of lead present in samples from a lead processing waste site. The methods and techniques for the ORP-pH measurements were investigated using known standard solutions made in the laboratory, samples from a ferric oxide waste disposal pond at a rutile production plant, and samples of well water and stream water from the lead processing waste site. ORP values were measured from 5 to 80 °C, from pH 1 to pH 12, and at various ratios of oxidant to reductant. The ORP-pH values can help identify valence values and species of ions present, including those of major, minor, and trace concentrations, and also indicate possible reactions at various pH values. The ORP measurements versus temperature yield data from which thermodynamic values can be calculated. The application and limitations of these measurements are discussed, and a brief discussion of the computational program to identify species of lead is presented.

Jan 1, 2010

By M. G. Zabetakis

The use of liquid hydrogen as a high-energy fuel introduces numerous hazards not ordinarily associated with the use of other more conventional fuels. These hazards are attributable to the unique properties of hydrogen in the liquid and gas states (table 1). Since little work has been conducted on explosion and related hazards of cryogenic fuels, a research program was undertaken to obtain basic data on such dangers for hydrogen and other combustibles under these conditions. These data were used to outline emergency procedures for protecting personnel and equipment when an accidental spillage of liquid hydrogen occurs and to establish a quantity-distance table for the storage of this fuel. The vaporization of liquid hydrogen from a surface is treated as a prob¬lem in heat transfer theory. Two extreme cases are briefly considered: (1) The transfer of heat occurs at constant temperature drop between, the boiling liquid and the hot surface, and (2) the transfer of heat is limited by the rate at which it can flow to the surface from a hot insulating medium. The available data indicate that the former case (1) is applicable when vaporizing from a conducting surface and, initially, when vaporizing from an insulating medium; the latter case (2) is applicable after initial flash vaporization has occurred from the insulating medium. The vaporization rate determines in part the rate at which flammable hydrogen vapor-air mixtures are formed above a spill area. However, the rates at which heat is transferred to the vapor, and air is brought in contact with it also are of importance. Accordingly, the distribution of flammable mixtures above a spill area was determined experimentally. In general, flammable mixtures were found to be both above and within the visible vapor cloud.

Jan 1, 1961

By R. W. Charles

The Los Alamos National Laboratory, under the sponsorship of the U.S. Department of Energy; is involved with laboratory and field experiments to assist in development of the Hot Dry Rock concept of geothermal energy. The field program consists of experiments in which hot rock of low permeability is hydraulically fractured between two wellbores. Water is circulated from one well to the other through the fractured hot rock. Our field experiments are designed to test reservoir engineering parameters such as heat-extraction rates, water-loss rates, flow characteristics including impedance and buoyancy, seismic activity, and fluid chemistry. Laboratory experiments were designed to provide information on the mineral-water reactivity encountered during the field program. Two experimental circulation systems tested the rates of dissolution and alteration during dynamic flow. SOlubil ity of rock in agitated systems was studied. Moreover, pure minerals, samples of the granodiorite from the actual reservoir, and Tijeras Canyon granite have been reacted with distilled water and various solutions of NaCl, NaOH, and Na.CO.. The results of these experimental systems are compared to the observations made in field experiments done within the hot dry rock reservoir at a depth of approxi-mately 3 km where the initial rock temperature was 150 to 200°C.

Jan 1, 1981

By C. M. Lesher, R. R. Keays

"The komatnte-associated Fe-Ni-Cu sulphide mineralization at Kanihalda, Western Australia, is generally believed to be magmatic in origin, but a number of postmagmatic processes significantly modified the original distribution, structure, texture, mineralogy and chemistry of the ores. Two important types of mobilized magmatic sulphides are interpillow/interbreccia sulphides and hydrothermal vein-type sulphides. Interpillow and interbreccia sulphides occur interstitial to pillowed or volcaniclastic footwall metabasalts beneath or adjacent to the stratiform contact ore horizons. They are mineralogically and compositionally similar to massive ores (and are similarly depleted in PGE relative to the compositions of bulk samples of mined ores), but normally do not contain the distinctive chalco-phile ferrochromites characteristic of contact ores. They are interpreted as magmatic sulphides that have been mobilized from the overlying or adjacent massive sulphide layer during peak tectono-nietamorphism.Hydrothermal sulphide-quartz + albite veins also occur in the footwall metabasalt and contain unannealed deformation fabrics indicative of emplacement during retrograde metamorphism. The high Ni and Pd contents of these sulphides (7-13% Ni, up to 70 ppm Pd) indicate that the metals have been derived from the spatially associated komatiites and/or contact ores, consistent with the Pd depletion previously inferred for massive ores. Very low Ir contents and high Pd/Ir ratios of the vein-type sulphides confirm an aqueous transportation-deposition mechanism; hydrothermal transfer of PGE results in strong decoupling of Pd from Ir.There appears to be a complete continuum of sulphide mobilization at Kambalda ranging from whole-scale phy sical dislocation (fault offset ores) and selective mobilization (stringer sulphides) through nietamorphie replacement (interpillow/interbrec- cia sulphides) to jiydrothermal dissolution and redeposition (vein-type sulphides)."

Jan 1, 1984

By J. H. E. Jeffes, K. T. Jacob

Solid oxide galvanic cells, of the type: Pt,Ni-NiO | Solid electrolyte | O(metal),Cermet,Pt, were used to measure the activity coefficient of oxygen in liquid Cu at 1 100 and 1 300°C and in Pb at 1 100°C. Similar cells were used to study the activity coefficient of oxygen in the whole range of Cu + Pb alloys at 1 100°C and in Pb-rich alloys at 900 and 750°C. The results obtained are discussed in terms of proposed solution models. An equation based on the formation of 'species' of the form M(2)O in solutions of oxygen in binary alloys is shown to fit the experimental data

Dec 1, 1971

By Susan Brink

The U.S. Bureau of Mines is investigating the potential of in situ leach mining a variety of Cu, Mn, and Au-Ag ores. Geologic characterization of ore samples from laboratory leaching experiments is conducted both prior to and after leaching to assess the effects of leaching on the chemistry, mineralogy, and texture of the rocks. The identification and chemical compositions of ore, gangue, and reaction products are determined by a combination of techniques such as reflected and transmitted light microscopy, X-ray diffraction, electron diffraction, electron microprobe analysis, and backscattered electron imaging with scanning electron microscopy. The distribution of the desired metal in various mineral phases can be illustrated using elemental X-ray maps. The potential of reactive gangue minerals to rob Cu from leach solutions is investigated with the aid of transmission electron microscopy. Porosity and permeability are measured to determine how effectively the host rock can transmit leach solution. Textural relationships between ore, gangue, secondary reaction products, and fluid channelways are determined by petrographic examination and are documented by optical photomicrographs and secondary electron imaging. Representative sample selection is described, and several epoxy impregnation and sample mounting techniques are discussed.

Jan 1, 1991

By Qingwen Shi, Yun Zhao, Brijes Mishra

The effect of discontinuities on the fracturing and mechanical behavior of shale has been extensively investigated on a laboratory scale in previous works. It is well agreed that the lamination properties, including discontinuity and lamina properties, affect the behavior of shale. However, it is still unclear how the lamination properties are affecting the stability of the shale roof in an underground coal mine entry. This paper investigated the effect of lamination properties using the discrete element method on a mine-scale entry model as an extension to the previous work conducted on laboratory scale models.

Jan 11, 2022

By H. O. Seigel

Induced Polarization includes many types of dipolar charge distributions set up by the passage of current through consolidated or unconsolidated rocks. Among its causes are concentration polarization and electrokinetic effects in all rocks and the phenomenon of Overvoltage in rocks containing electronic conductors such as metallic sulphides and graphite. In normal rocks the polarization effects may be usually con-fined within relatively narrow limits and any large departures may be at-tributable to the presence of electronic conductors. In practice, Induced Polarization is measured in one of two ways. In the first a steady current of some seconds duration is passed and abruptly interrupted and the slowly decaying transient voltages existing in the ~round are measured after interruption. This is known as the "pulse", "transient", or Direct Cur-rent Induced Polarization (D.C.I.P.).The second method entails a comparison of apparent resistivities using sinusoidal alternating current of two or more frequencies, generally within the range of 1/10 to 10 c.p.s. Induced Polarization extends the

Jan 1, 1962

By K. C. Misra, W. Wrightson Jr.

The Lick Fork prospect shows appreciable nickel sulphide mineralization in a narrow, steeply dipping, layered sequence of metamorphosed hornblende peridotite, gahhro and hornblende gahhro, intrusive into the Pedlar Formation (charnockitic pyroxene granulite) of the Virginia Blue Ridge Complex (Precambrian). Rocks of the intrusion have equilibrated to granulite- facies metamorphism, as indicated by pervasive polygonal texture of silicate aggregates, development of biotite- and hornblende-preferred orientation, compositional equilibration of the silicate minerals, the Mg-Fe2+ (orthopyroxene-dino- pvroxene) distribution coefficients (average 0.57), (MgO + FeO + Fe20 3)/Al20 3ratios in orthopyroxenes, and Ti contents and AI(i\)/A I(\i) ratios of hornblendes. The sulphides, consisting of pyrrhotite-pentlandite (with up to 4 wt% Co)-chalcopyrite-pyrite-marcasite-violarite- bornite—mackinawite, are virtually restricted to the ultramafic unit of the intrusion and constitute 20-30% of the samples of hornblende peridotite studied. Although the basal accumulation of the sulphides may suggest magmatic segregation, sulphide- silicate textures typical of sulphide liquid immiscibilitv are not present, even in the sparsely mineralized gahbro units. On the other hand, the transgressive and relict textures are strongly suggestive of replacement of the silicate minerals by sulphides. These include chaleopyrite ± pyrrhotite ± pentlandite (violarite) ± pyrite ±magnetite veins crosscutting silicates, sulphide penetration into silicates at silicate-sulphide contact zones, rounding of silicate grains against sulphide matrix, and islands of silicate minerals (olivine, hornblende, pyroxene, biotite) in sulphide masses. Metamorphic mobilization of pre-existing sul­ phides is a possibility, but involvement of post-metamorphic, hydrothermal fluids is suggested by the following features: paucity of annealing and deformation textures in the sulphides, replacement of metamorphic and deformed silicates, lack of differential sulphide mobilization and the common occurrence of sulphides along grain boundaries and triple junctions of poly gonal silicate aggregates. The consistent association between sulphides and hydrothermal alteration products of silicates suggests that they are cogenetic. The hydrothermal fluids may have merely mobilized and concentrated the pre-existing, disseminated, magmatic sulphides, or there may have been significant addition of sulphides during this process. This question cannot be resolved unequivocally with the existing data.

Jan 1, 1984

By A. L. McAllister

"MASSIVE sulphide deposits are found in two areas of New Brunswick, the St. Stephen area and the Bathurst-Newcastle area. In both, the geology in the immediate vicinity of the sulphide bodies is largely inferred from drilling results as outcrop is not plentiful and is, in fact, almost lacking in most places. With few exceptions these deposits have not been explored by underground methods. Consequently much of the. detail on the geology will only become known over a period of years as economic conditions make mining feasible.Much of the information contained in this paper has been supplied directly by company geologists. As a result of the number of contributors, some confusion of nomenclature bas to be anticipated. Cross-sections and plans of the individual deposits are, in most cases, as supplied by the companies concerned. Most of the interpretations are the responsibility of the author."

Jan 1, 1960

By W. K. Summers

During the past few years monitoring systems have been installed to measure the effects of environmental changes on the ground-water resource. The design of a monitoring system depends upon the designer's perception of how the environmental factors merge with his perception of the ground-water flow system. The validity and representativeness of measurements made during a monitoring program depend upon the validicy of the designer's perceptions and concepts. To optimize the design of a ground- water monitoring program the designer should make preliminary measurements to confirm his assumptions.

Jan 1, 1985

By Fieldner. A. C.

"In preparing this paper, an attempt was made to obtain results of plant-scale carbonization tests on washed and unwashed coal tram to same mine. A letter. in which the following questions were asked, was sent to some 50 coke-oven superintendents and others who might be interested:“What is the influence of washing coal on:(1) The chemical and physical properties of coke, as for example, the size, the amount of breeze, the fracture, strength, cell-structure, etc.(2) The quantity and quality of gas and by-products.(3) The capacity of the ovens.(4) The composition of the coal..""Your general opinion, as well as any specific data or results of testa, on this important subject will be greatly appreciated.""Of the 45 replies received, 24 stated that they had never used washed coal; 11 had used washed coal but had no comparative data on similar coals washed and unwashed; 7 answered some of the questions based on their general experience; and 3 gave some test data on Pittsburgh bed coal from western Pennsylvania. In none of the three tests did the washed coal come from the same mine as the unwashed. The washed coals in the three tests were from the same washery - one of modern construction in which the operations are under careful technical control in order to give a uniform product containing a minimum of surface moisture. The unwashed coals which were previously used in these plants were from different nearby mines in the same coal bed, and were supplied by the same company. Obviously, no sweeping or finale conclusions can be drawn from these few tests on coal from a single washery. Therefore, the writer vas obliged to consult the literature, coal-carbonization and coal-washing engineers, and other authorities to supplement the fragmentary information gleaned from the questionnaires in order to present a picture of chat gas engineers may expect from the use of washed coal in a carbonizing plant."

May 1, 1930

By K Kuganathan

This paper describes a new methodology that can be applied to compare several bench extraction strategies requiring backfill. The method is applicable at the planning or operational stages and can be used to maintain dilution within design parameters and improve the overall economics of bench stoping operations. The parameters influencing bench performance have been empirically rated based on economical, geomechanical, operational and backfill properties. Four different extraction strategies have been considered and rated from most preferred to less preferred using an integrated approach to bench extraction.

Jan 1, 1998

By Christian F. Baiz

The author will present a discussion of the steps which must be taken by the prospective developer of a small mining operation to establish technical credibility when seeking financial backing. Particular emphasis will be given to the differing levels of technical work (and their relative cost) which must be accomplished to supply the information necessary to satisfy potential investor groups, whether they be other mining companies, equity investors, or financial institutions such as venture capital firms or commercial banks.

Jan 1, 1981