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By Alexander Sutulov

It is calculated that since the beginning of last century, which practically coincides with the beginning of the Industrial Revolution, our civilization has consumed around 239.5 million tons of copper (see: Table 1). According to the most pessimistic projections of today, with only a 2.5% annual growth rate in demand, we are bound until the end of this century to consume another 200 million tons of copper in remaining 17 years. A recent study made by US Bureau of Mines (1) indicates that the proven ore reserves of 150 major operating mines and about 120 deposits sufficiently explored for development and feasibility studies accumulate a total mass of 49.3 billion tons of ore, assaying an average of 0.82% Cu and containing around 324 million tons of recoverable copper. Consequently, there is a high grade of probability that the bulk of our future ore supplies, for our demand of, say, next 25 years will cane precisely from these mines. The interesting point in USBM study is that it indicates the recoverable byproduct content of these ores and which is: 118.2 million troy ounces of gold 2277.4 million troy ounces of silver 7.1 million tons of lead 24.7 million tons of zinc 1.3 million tons of nickel 3.1 million tons of molybdenum 765 thousand tons of cobalt, and 720 thousand troy ounces of platinum. This information gives us a relatively reliable profile of our future ores for next 25 years, and thus makes possible evaluation of byproduct credits in our future copper mining and producing activities.

Jan 1, 1983

By T. Hackett

Western underground coal reserves are tremendous, but recovery in western seams can be poor because of mining problems caused by deep cover, geologic anomalies, and thick seams. For instance, many seams contain a rock parting too thick to be extracted economically with the coal. This forces the operator to mine the coal above or below the parting. Subsequently, the rock pressures induced by mining make the part left difficult or impossible to extract by standard mining methods. Because upper and lower parts of the seam are frequently of minable thickness, the presence of rock partings can result in a significant loss of coal. Given a longwall recovery of 60 pct and equal thickness for the two parts of the seam, overall recovery is reduced to less than 30 pct if one part only is mined. The coal left in place is unavailable to meet the nation's energy needs, or to produce revenues for coal companies or government. [ ] Multi-slice longwall mining has the potential to recover the portion of split seams that are now left in the mine. Using superimposed standard longwalls with chain pillars, overall recovery could be doubled, depending on panel and pillar widths. Using a combination of advancing and retreating longwalls in descending slices, overall recovery could be improved to more than 80 pct. Because of the potential for improved recovery, the Bureau of Mines is analyzing the ground control factors affecting multi-slice longwall under western mining conditions and is conducting field trials at a planned multi-slice operation.

Jan 1, 1987

By Clarence Hardy Long

In January of 1969 the United States Department of Health, Education and Welfare, through the National Air Pollution Control Administration, published a series of Air Quality Criteria (4'S) and Control Techniques (6,7) for air pollutants in compliance with the 1967 Clean Air Act which will affect the operation of all fuel burning equipment in the very near future. The design of equipment for the future which will use fossil fuels will also be affected. The purpose of this paper is to discuss some of the modifications which might be anticipated in the future for fuel burning equipment. One class of the several air pollutants looked at first by the USDHEW was the sulfur oxides. Other pollutants, such as nitrogen oxides, will be studied and controls for these will supposedly be written in due time. The obvious use of low-sulfur fuels, coal, oil and natural gas is suggested by the Control Technique(6). Conversion to other sources of power, such as nuclear energy and hydropower, is also suggested. The statement is made that since possible hydroelectric sources are limited and nuclear plants are not yet available on a large scale, the changeover to these sources of power will not be overnight. The bulletin (6) suggests that one possible solution in some areas may be the use of low sulfur coals for short periods of time during periods of severe air pollution. A curve showing the effect of this was given in the 1969 April issue of the Power magazine, where A. E. Boyer and F. B. Kaylor of Stone and Webster also described a computer program called DOSAGE which might be used to check weather, temperature, humidity, wind direction and velocity, and sound an alarm when that 0.1% of the time per season is here that requires the use of low-sulfur fuel. Inversion is eminent! Once this has passed operation on regular fuel may be resumed. This would mean a separate storage

Jan 1, 1970

By Mahmood B. Mirza

The geology of the Gulf Coast Salt domes has been extensively studied by Kupfer (1,2,3,4,5), Atwater (6,7), Balk (81, Hawkins (9), and Wharton (10). dominant geological feature of Southern Louisiana is the Gulf Coast Geosyncline. The axis of this geosyncline corresponds with the present day coastline of Texas, Louisiana, Mississippi, Alabama and Florida. This geosyncline has been continually subsiding since Cretaceous times and receiving large deltaic accumulations of sediments from Central North America. These accumulations progressively thicken toward the South. In the vicinity of the Coast, these sediments are reported to be about 40,000 feet thick. Another dominant feature of the region is the large number of salt domes scattered along the Gulf Coast (fig. 1). Typically, these domes are roughly cylindrical in shape, 1 to 5 miles in diameter, and extend to more than 20,000 feet in depth. It is hypothesized that these domes are derived from the thick Louann salt formation lying below the deltaic sediments. Due to its low specific gravity and buoyancy, the salt layer protruded upwards plastically and pierced the overlying strata. As a result of this upward flow, the adjacent strata are locally lifted upwards, creating excellent traps for petroleum accumulation.

Jan 1, 1979

By Bo Arvidson

SALA MAGNETICS, INC. is now operating a 15 tph continuous high gradient magnetic separator, the SALA-HGMS® Mark III Carousel, as part of a complete mineral processing pilot plant installed at Sala's Cambridge headquarters. The Mark III can generate a maximum magnetic field of 18 kG making it possible to process even weakly magnetic, finely ground ores and ore tailings on a continuous basis at the performance level achieved in Sala's cyclic high gradient magnetic separators. Test results on iron ores, clay, and decoppering of molybdenum concentrate will be discussed. Bench scale tests have been performed on all of these materials using the SALA-HGMS® Model 10-15-20 Cyclic Magnetic Separator. A direct correlation may be made between cyclic and carousel results. Sala's Mark III Carousel high gradient magnetic separator is designed to permit scale-up to machines capable of processing two hundred (200) tons of ore per hour and more.

Jan 1, 1976

By Brenda J. Wolfe

Following successful laboratory and pilot plant investigation of dewatering characteristics of molybdenum concentrate produced by a Chilean copper/moly producer, two (2) DENVER SALA 500 Series Tube Press Filters were installed in 1994 to handle the total production volume. Moisture requirements in the filter cake have been consistently met, eliminating the need for thermal drying after filtration. Operating data and Tube Press Filter are described herein.

Jan 1, 1995

By J. J. Webb

At Kerr-McGee's Galatia Mine in southern Illinois, the need for safe and efficient longwall moves prompted a detailed planning effort. Galatia Mine operates two longwalls on separate coal seams with different geologic conditions. An overview of the longwall move planning as related to manpower training, roof control, ventilation, transportation, equipment recovery and setup will be discussed. The impressive safety record achieved during each of the longwall moves at Galatia Mine verifies that health and safety planning does play a major role.

Jan 1, 1994

By David C. Grant

During in situ uranium mining using ammonium bicarbonate lixiviant, the ammonium exchanges with cations on the ore's clay. Mter mining is complete, the ammonium may desorb into post-leach ground water. For the particular ore studied, other chemicals (i.e., uranium and selenium) which are mobilized during the leach process, have also been found in the post-leach ground water. Laboratory column tests, used to simulate the leaching process, have shown that aluminum chloride can rapidly remove ammonium from the ore and thus greatly reduce the subsequent ammonium leakage level into ground water. The aluminum chloride has also been found to reduce the leakage levels of uranium and selenium. In addition, the aluminum chloride treatment produces a rapid improvement in permeability.

Jan 1, 1982

By G. S. Adisoma

To address the problem of grade estimation in a general three-dimensional shape and the uncertainty associated with the estimate, the technique of jackknifing/block kriging short-cut is proposed. A new estimator called jackknife kriging is introduced first. Through the jackknife variance, a confidence limit for the reserve grade estimate can be calculated. Unlike the kriging variance, which is more a measure of data configuration and is independent of data values, the jackknife variance reflects the true variability of the data. This approach provides a simple way to set a confidence level for global estimation of resources.

Jan 1, 1995

Gold cyanide equilibrium adsorption isotherms in the loading range typical of operating carbon-in-pulp/carbon-in-leach plants have been established and the effect of various cations and the presence of copper cyanide species quantified. It was found that the equilibrium loading of gold was enhanced by the presence of sodium or calcium, with calcium having an order of magnitude stronger effect. The presence of copper has an adverse effect on the equilibrium loading of gold. A unified model was developed to predict the effect of sodium and calcium concentrations in solution and the competitive carbon adsorption of copper on the equilibrium loading of gold on carbon. A satisfactory agreement between the measured gold equilibrium loadings and the model results was obtained over a wide range of solution conditions.

Jan 1, 2010

By Yashar Pourrahimian, Roberto Noriega

Truck fleet dispatching plays a crucial role in reducing operational costs and fulfilling operational targets in open-pit mining operations and is subject to large uncertainty arising from the operating cycles of trucks and loading equipment. This paper proposes a reinforcement learning-based truck dispatching system. Reinforcement learning is a machine learning area that deals with learning an optimal sequential decision-making strategy in an uncertain environment. An open-pit load-and-haul simulation is developed that also captures the truck movements and interactions in the shared road network, and a Neural Network is successfully trained to suggest truck dispatching decisions in a real-time manner.

Jun 25, 2023

By Roy H. Werner

The environmental demands on the mining industry coupled with rising production costs have created a need for a low cost sludge removal system. The HYDRA* system meets these demands by offering a unique means of removing settled solids from the bottom of a clarifier or a thickener. This underflow system combines experience and proven concepts to form a low cost sludge removal system. The HYDRA system incorporates a flexible design that can be adapted to any settling area. The components are readily available and cost less than a conventional clarifier or thickener. Existing technology developed by preparation engineers provides for retrieval and recovery of mine preparation plant refuse. However, past retrieval methods have been extremely costly. The HYDRA system, because of its low cost, makes the complete process of retrieval and recovery economically feasible. This allows wasted resources to be converted to a saleable product.

Jan 1, 1975

By T. P. Meloy

Like our wives, the comminution of brittle solids is easy to recognize but difficult to describe. However, describing it we must. Describing the fracture mechanism of brittle solids permits the eventual mathematical quantification of the results, process optimization and control strategies. This paper presents a physical model of brittle solid comminution that explains why the slope of the log-log size distribution curves have a slope of one or less in the smaller particle sizes. To develop the hypothesis, modifications of the Gaudin Meloy physical model are made. In brittle solids, comminution takes place by cracks propagating through the material. These cracks may bifurcate as they move. Cracks may terminate either on the original surface of the material, or on a secondary crack within the material formed earlier in the comminution process.

Jan 1, 1994

By Maurice L. Madden

An investigation was undertaken for a ground water discharge plan for the Chino mining complex near Hurley, New Mexico. Operations which impact ground water include dump leaching, storage reservoirs, and tailings seepage. The investigation included both hydrogeological data collection and laboratory analysis. A conceptual understanding of surface water and ground water was then developed. Surface water and ground water models were used to match existing conditions and predict the impact of operational modifications. The study concluded that runoff and resulting leach reservoir overflows were primarily responsible for the ground water degradation. Tailings seepage represents a smaller part of the impact.

Jan 1, 1984

By Dennis F. Koschak

Production tests at Reserve Mining Company's iron ore pelletizing plant established that rubber-lined balling dm produce a green pellet equivalent in quality to those produced in conventional balling drums equipped with reciprocating cutter bars. The flexing action of the rubber liner prevents concentrate buildup in the drums, eliminating the need for a cutter bar. Advantages of the rubber-lined drum includes a reduction in maintenance and operating manpower, reduced bentonite consumption with less drum surging, reduced power consumption, and improved drum on time.

Jan 1, 1983

By R. L. Grayson

The health and safety of employees, efficiency of the operating system and production are paramount goals in underground coal mining. The section foreman assumes responsibility for making his part of the total system function to meet these goals. However, section foremen often have not been prepared to assume the full range of their responsibilities upon becoming a supervisor. This discussion addresses the full range of section foreman responsibilities and concomitant authority. Management principles that must be mastered by him are presented, and performance expectations as well as criteria for their evaluation are examined. The benefits realized from effective foreman training are discussed.

Jan 1, 1985

By Bernard E. Weichman

The oil shales in the Piceance Creek Basin of northwest Colorado occur in the Parachute Creek member of the Green River formation. The oil shales were deposited in a unique environment of deposition which caused the mineral nahcolite (NaHC03) to be precipitated within the oil shales. Post-depositional tectonics resulted in extensive fracturing of the Middle Zone of the Parachute Creek member, and to a lesser degree portions of the Lower Zone, which allowed percolating ground waters to dissolve the nahcolite in the fractured portion of the oil shale beds which is characterized by broken porous oil shale, certain beds of which have collapsed into rubble and debris. The extent and porosity of the Leach Zone aquifer is dependent upon the percentage of kerogen and nahcolite originally deposited in the oil shale. Any oil shale development program in the Piceance Creek Basin of northwest Colorado will need to be preceeded by an extensive study of the Leach Zone in order to determine the effects on a mining program.

Jan 1, 1973

By D. An, J. Withers

A nano-scale investigation has been carried out by applying an AFM (atomic force microscope) to study in situ the adsorption of various collectors, i.e., oleic acid, octanohydroxamic acid (HA), and salicylhydroxamic acid (SHA), on bastnaesite in aqueous solutions. The obtained AFM images show that the surface morphology of bastnaesite changes greatly after it contacts the solutions of the collectors, suggesting that all these collectors can effectively adsorb on bastnaesite. Increasing temperature can help increase the adsorption of oleic acid on bastnaesite. FTIR (Fourier transform infrared) results also show that all these collectors adsorb strongly on bastnaesite with a strong absorbance spectra being detected, which confirms with the results obtained with AFM imaging analysis. In general, hydroxamic acid collector (HA and SHA) adsorbs on bastnaesite mainly in the form of insoluble metal hydroxamate. This specific adsorption mechanism explains that a high selectivity with a moderate collectivity will be achieved with a hydroxamic acid collector for the flotation of bastnaesite. INTRODUCTION Rare earth metals, which are very important to modern industry, are generally extracted from numerous rare earth minerals. In practice, however, the actual extraction of rare earth is mainly from bastnaesite, monazite and xenotime. The Mountain Pass mine is one of the largest rare earth mine in the world, at which the main rare earth mineral is bastnaesite. In the past years, froth flotation has been applied to the beneficiation of Mountain Pass ore. In practice, the rare earth ore is usually crushed, milled and further separated from calcite, barite and other gangue minerals by froth flotation, in which the rare earth oxide-bearing minerals stick to aerated bubbles in the pulp and float to the surface, leaving the gangue at the bottom of the flotation cell and disposed of as tailings.(Bulatovic, 2010) In spite of the fact that froth flotation has been applied to treat the bastnaesite ore at the Mountain Pass mine, the rare earth oxide (REO) recovery is still low,(Anderson, 2015) especially compared to the one obtained with sulfide flotation. For example, the typical recovery obtained at the Mountain Pass mine was only about 70%. This may be due to the low selectivity of the collector (oleic acid). In addition, to enhance the flotation selectivity, the pulp in the mine circuit has to be heated up to 70 to 90°C and it involves a lot of energy consumption. Last but not the least, a lot of depressants have to be added to improve the selectivity of flotation process. Therefore, it is critical to re-examine the existing flotation process at the Mountain Pass mine and seek any chance of improvement. (Anderson, 2015)

Jan 1, 2019

By E. G. Noble

Microbial leaching is being investigated as a method for recovering the metal values from a domestic low-grade manganese wad ore. Early work showed that heterotrophic microorganisms present in the ore solubilized manganese when cultured in a glucose-mineral salts medium. More recent shake-flask tests using molasses as the sole nutrient source extracted 97 pct of the manganese from minus 300- µm ore in 4 weeks. Column bioleaching with the molasses medium solubilized 99 pct of the manganese from minus 6.3-mm ore in 50 weeks. The results of flask, column, and lab-scale heap bioleaching studies are presented.

Jan 1, 1991

By B. Derin

In this study, the Reddy-Blander model was applied to predict the sulfide capacity (CS) values of FeOx-CaO-SiO2, FeOx-MnOx-SiO2 and FeO-MgO-SiO2 ternary slags, which were experimentally studied in the literature within the temperatures between 1,673 and 1,923 K. As expected, sulfide capacity values of the slags increased with increasing temperature and decreased with increasing acidic content. The model was found to be in agree-ment for all slag systems at the temperature range of 1,773-1,923 K. However, a disagreement occurred when the basic content was relatively high, at 1,673 K for FeOx-CaO-SiO2 and FeO-MnOx-SiO2 slags. The effect on the CS of high amounts of Fe+3 and Mn+3 in the slags is discussed.

Jan 1, 2011