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By F. Calizaya

This study summarizes the results of various numerical and laboratory experiments per-formed to study the effect of airflow recirculation on gas concentration. The numerical exercises were carried out on a simulated mine ventilation net-work. The laboratory experiments were conducted at the Mackay School of Mines' airflow monitoring system in Reno, Nevada. In both cases, the airflow was recirculated through the system by means of a main fan and a set of booster fans. The booster fans were positioned to produce two types of recirculation: In line and Cross-cut. For each type, various recirculation conditions were generated by changing the booster fan pressure. During each test, the gas emission rate at the simulated working face was kept constant. The study illustrates the conditions under which controlled airflow recirculation may be used to solve a district ventilation problem.

Jan 1, 1991

By Chris Roos

The mining industry has made strides in planning for operations to be safe for the workforce and public, to protect the natural environment, and to maximize value for shareholders. However, many of the techniques used to accomplish these goals are based on estimated models of mineral content, production efficiency, and economic performance. The industry has begun to recognize the need for understanding the uncertainty in these models, how it affects their decisions, and what the potential impacts are for each project. The challenge has become how technical professionals can effectively communicate the impact of this uncertainty and its importance to both technical and non-technical audiences. This paper presents mining engineers (and other technical professionals) with traditional and modern principles of data visualization and technical communication that can assist with communicating the effects of uncertainty in the mine planning process.

Jun 25, 2023

By D. L. Leach

This report covers laboratory experiments simulating in situ copper recovery from primary sulfide ores in sulfuric acid systems pressurized with oxygen. Copper extraction and acid consumption data are correlated with temperature in the range 50-150°C and quenched pH in the range 0.25-2. Adverse changes in the chemical composition of the leach solution and the formation of gangue-mineral alteration products and secondary sulfides can severely limit the extraction of copper above 90°C. Keeping the pH below the self-buffered value of about 2 and the temperature below about 110°C produces the maximum extraction rates. Forcing the pH too low not only results in excessively high acid consumption but may also limit the extraction of copper at temperatures above 100°C.

Jan 1, 1975

By H. P. Cole

A team of researchers at the University of Kentucky, working under a USBM contract, developed over 65 simulation exercises for teaching and testing problem-solving and decision-making skills to miners and mining engineers. These skills involve both improving judgment and decision making in mine emergencies and enhancing the learning of real-world engineering design principles. The exercises are ideally suited for either latent image format or for computer-aided instruction. Exercise features are summarized, the structure and field testing of typical exercises described, and sample frames of individual exercises presented. Empirical data are summarized that describe the effectiveness of using these short, time-efficient performance tasks that simulate real problems and that provide immediate corrective feedback for teaching and testing critical skills. I

Jan 1, 1991

By R. R. Klimpel

Over the last six years, several new commercial families of sulfide mineral collectors have been developed. This paper summarizes some plant data and use experiences gained with each of these product families. The first is a series of products (F-series) based on a chelation mechanism of attachment. The second of these families is a series of products (S-series) based on an electrochemically controlled mechanism of attachment. The major advantage of the F-series collectors is the very high metal recovery capability in complex ores involving Au, Pt, Zn, Ni, and mixed Cu minerals. The major advantages of the S-series collectors are the very high pyrite rejection capability along with reduced lime requirements in Cu/Mo plants.

Jan 1, 1995

By Alan J. Solomon

The function of advertising is communication. Viewing the advertisements of mineral suppliers exposes the reader to a broad spectrum of purposes: announcements of new products, availability and supply, departmental services, company image, etc. It is the advertiser's hope that the message being conveyed is the same message being perceived by the viewer. To maximize this probability, the advertiser at least must carefully construct precise copy, identify the target audience and select the appropriate advertising medium. A truly successful and efficient ad, however, also must accurately reflect a product's life cycle, i.e., the rise and fall in demand for a product. Buggy whips and radio tubes are classic examples of items formerly in high demand. Industrial minerals are similarly affected by occurrences of product life cycles.

Jan 1, 1983

By Jr. Kirschner

An abandoned waste impoundment located within a portion of the Kellogg, Idaho Superfund site constitutes a field research area for studying the feasibility of recovering heavy metals in-situ from unsaturated mine and mill wastes. A prototype in-situ leaching cell has been evaluated using liquid-phase tracer tests and other hydro-geologic tests prior to introducing a lixiviant. The results of the tests suggest that: (1) the cell can be operated excursion-free with a low-density lixiviant at an injection/withdrawal rate of approximately 0.32 l/s; and (2) each hydro-geologic unit is highly heterogeneous at the different scales studied.

Jan 1, 1993

By Donald T. Mylar

It is axiomatic that in designing a bulk material handling system the primary consideration is the functioning of the machines. The structure is secondary -its reasons for being are to support, enclose and provide access to the machine, for servicing. This results in a wide variety of supporting structures. Other considerations are: plant layout, local soil conditions, climate, local laws and codes, and last, but by no means least, the Customer's wishes.

Jan 1, 1971

By G. G. O. O. Uwadiale, M. A. U. Nwoke

The recovery of iron from low-grade (31.6% Fe) Muro iron ore was investigated using reverse anionic flotation of quartz. Tests were performed to investigate the effect of pH, the effects of using distilled vs. tap water as the flotation medium and the effects of using cassava starch vs. dextrin for the depression of iron minerals. The optimum results were obtained around pH 10 and 11, and cassava starch was superior to dextrin in depressing iron oxides. Investigations at pH 11 using cassava starch and distilled water resulted in a concentrate grade of 69.4% Fe with a recovery of 84.4% Fe. Under the same conditions, the use o f dextrin produced a concentrate grade q f 65.9% Fe with a recovery of 78.6% Fe. Investigations at pH 10 using cassava starch and distilled water resulted in a concentrate grade of 60.2% Fe with a recovery of 83.9% Fe, and under these conditions the use of dextrin produced a concentrate grade of 56.1 % Fe with a recovery of 81.5% Fe. Flotation studies conducted at pH 11 using tap water and cassava starch resulted in a concentrate grade of 70.4% Fe with a recovery of 92.7% Fe. This demonstrated the superiority of tap water over distilled water in the reverse anionic flotation process. Investigating the effect of calcium ions on the activation and flotation of quartz with oleic acid revealed that a calcium ion concentration of 50 to 100 ppm was optimum.

Jan 1, 1996

By James E. Lawver

The agriculture industry has made great strides during the past decade to increase agriculture yields through increased use of fertilizers. Increased use of fertilizers may prevent or at least delay mass starvation due to the alarming increase in world population. Phosphate was added to soil as a plant nutrient in the forms of calcined bones at least 2 000 years ago, (1) and man has used phosphate minerals as a source of fertilizers in one form or another for at least 100 years. During 1977 the world produced about 116 million metric tons of phosphate rock, with about 86% used for fertilizers and another 4% for animal feed supplements. More than three-fourths of the total production comes from the United States, Morocco, and the Soviet Union. From a mineral beneficiation point of view, the major sources of phosphate rock and the methods of beneficiation can be classified as follows. Marine deposits not containing appreciable carbonate minerals, marine deposits requiring a francolite carbonate mineral separation, igneous deposits not containing appreciable carbonate minerals, and igneous deposits, requiring an apatite carbonate mineral separation.

Jan 1, 1978

By George K. McCord

It is a pleasure to participate in this Fall meeting of the Society of Mining Engineers to discuss energy conservation trends in the cement industry. Energy is the "life blood" of American industry, and the ability to use available energy resources efficiently may well determine the future of our nation and of its industries. The Federal Energy Administration has classified cement manufacture as one of several energy-intensive industries in the U.S. and has selected the Portland Cement Association to make a detailed study of possible energy conservation measures. Member companies of the Portland Cement Association represent about 85% of the cement producing capacity of the United States and 100% of Canadian capacity. Stated briefly, the purpose of the Association is to extend the uses of portland cement and concrete through research and development, market promotion, education, and public affairs work. PCA's general offices and research laboratories are located in Skokie, Illinois. Our staff of engineers, scientists, and research personnel make the PCA uniquely qualified to perform an energy conservation study of the kind requested by FEA.

Jan 1, 1975

By A. R. Negele

Kaolin-based pigments are the most widely used pigments in the paper industry. Several types are available and include standard hydrous, delaminated, calcined, chemically-structured, and most recently, composite pigments. Within each category, a spectrum of products is available to satisfy the application requirements of paper producers. The paper industry has a broad range of applications including fillers in woodfree and groundwood-containing papers, pigmented size press applications, ultra-lightweight and lightweight coated papers, coated merchant papers, cast coated papers and coated paperboard. Each application has its own set of performance criteria and suppliers must work with mills to identify appropriate product(s) to fulfill these requirements.

Jan 1, 1993

By AKIHIRO YOSHIMURA, HIDEKAZU KATO, KOTA TAKATORI, YASUNARI MATSUNO

Chalcopyrite (CuFeS2) is the most refractory copper mineral when treated in conventional sulfate media leaching systems. This study is the first to examine the use of a dimethyl sulfoxide (CH3SOCH3), or DMSO, solution containing copper chloride (CuCl2) in the leaching of chalcopyrite. The DMSO solution containing CuCl2 could selectively dissolve the valuable metals of copper (Cu) and gold (Au) from chalcopyrite while leaving minerals with little economic value, such as pyrite (FeS2), and the penalty element arsenic (As) in the residues. Leaching chalcopyrite using a DMSO solution that contains CuCl2 offers a number of advantages, including eco-friendliness and easy operation.

By C. Brown, N. Rayyan, T. H. Dubaniewicz

Lithium-Ion batteries (LIBs) have the potential to go into thermal runaway which introduces a new ignition source in hazardous environments such as gassy underground mines that may contain methane in the surrounding air. Researchers from the National Institute for Occupational Safety and Health (NIOSH) used an accelerating rate calorimeter (ARC) to induce thermal runaway in individual lithium-titanium-oxide (LTO) and lithium-nickel-cobalt-aluminum-oxide (NCA) LIB cells within a sealed enclosure with either no methane, a lean, a stoichiometric, or a rich methane-air mixture in the surrounding canister to determine if these LIB types would ignite the methane, causing an additive effect on overpressures. Canister pressures and maximum temperatures reached by the cells, surrounding air, and exhausted gases were measured in this study and remained consistent with varying methane concentrations.

Feb 1, 2023

By John M. Heckard

It all started with the National Environmental Policy Act of 1969, which establishes that Congress is committed to restore and maintain environ- mental quality. It directs all federal agencies to identify and develop methods and procedures so that environmental parameters and values will be given equal consideration in the decision-making process, along with economic and technical parameters. Section 102 of the Act directs, among other things, that all agencies will submit a detailed statement on: (1) the environmental impact of the proposed action, (2) any adverse environmental effects which cannot be avoided should the proposal be implemented, (3) alternatives to the proposed action, (4) the relationship between local short term uses of man's environment and the maintenance and enhancement of long term productivity, (5) any irreversible and irretrievable committments of resources which would be involved in the proposed action should it be implemented. Passage of this act has been followed by other legislation, both federal and state. The Water Quality Act of 1970 puts teeth into the previously existing Federal Water Pollution Control Act by requiring a "certificate of reasonable assurance that the activity licensed will not violate the applicable water quality standards." The Clean Air Act of 1970 requires that the Environ- mental Protection Agency establish national air quality standards, as well as standards for significant new pollution sources.

Jan 1, 1973

By Jaeheon Lee, Junmo Ahn, Jiajia Wu

To reduce the environmental footprint of hydrometallurgical processing of black mass from spent lithium-ion batteries (LIBs), a green leaching system based on glycine and sodium metabisulfite (Gly-SMS) was proposed. The leaching study demonstrated that the highest cobalt and lithium recoveries of 100 percent and 99.8 percent were achieved under optimal conditions. The leaching mechanism revealed that the dissolution of LiCoO2 in the Gly-SMS solution followed the shrinking core model. The apparent activation energies for cobalt and lithium were determined as 48.05 and 41.51 kJ/mol, respectively, indicating a surface chemical reaction controlling mechanism. The leachate was then processed by an acidification- precipitation technique with oxalic acid as the precipitant to remove cobalt. Glycine complexes with metal ions by zwitterionic ligand and recycles in the leaching-precipitation circuit, reducing the reagent cost. Compared to other studies, this leaching system has near-neutral operating conditions and is cost-effective, making it an economically viable alternative for treating cathode materials from spent LIBs.

Dec 1, 2024

By F. G. Miller

It is generally accepted that sulfur exists in coal in three forms: (1) pyritic, (2) organic, and (3) sulfate sulfur. Sulfate sulfur usually makes up less than 1% of the total sulfur content. Pyritic and organic sulfur, make up almost all of the total sulfur and occur in varying amounts in different coals and can vary greatly in coal of the same seam Pyritic sulfurs of 20% to 80% of the total sulfur have been reported Other authors have shown that it is not possible to remove the organic sulfur without chemically altering the coal. Chapman and Jones (1) state: "Organic sulfur, unlike pyritic sulfur does not exist as discrete particles, but is intimately associated with the coal structure, and as such it is not possible to remove it or reduce its concentration by physical means." Any success in removing sulfur has come about by removing pyritic sulfur by physical means; therefore, removal of sulfur in the pyritic form is the subject of this investigation. The extent to which any impurities can be removed from a particular coal can be determined by a washability study. Outside of crushing coal, to finer sizes or chemically altering the coal, there are no known methods of changing this inherent washability characteristic. The efficiency of various methods used to remove impurities can be determined by comparison of results produced at a yield to the results as shown by a washability study. In recent years heavy media processes have proven their ability to wash plus 28 mesh coal and nearly produce results shown to be theoretically possible by the washability study. Therefore, it is the objective of this paper to show various methods of treating the finer fractions of the coal, in the hope of developing a process, which can effectively produce in the fine fractions the efficiency of heavy media devices in the coarse.

Jan 1, 1963

By L. M. Cenegy

Introduction The formation of scale is common in gold ore processing plants. A working definition of such scale is: "A hard, tightly adhering deposit formed in place by the precipitation of calcium-bearing mineral compounds from water." The most common scale found in gold processing plants is calcium carbonate (CaCO3) although calcium sulfate (CaSO4) is occasionally a problem. The problem of scale in carbon strip circuits Carbon strip circuits present a particularly challenging scale inhibition problem. Many of the factors that tend to promote scaling are present in these systems. For example, carbon strip circuits are run at high temperatures and high pH levels and require long batch cycle times. Tortuous paths are encountered by the strip solution circulating through heat exchangers, pipes and elbows, causing transient pressure drops throughout the system. Severe conditions such as these cause the water to possess a high scaling potential and may lead to the breakdown of some of common types of scale inhibitors. Formation of scale Natural waters contain dissolved minerals and gases that promote scaling. One of the contained gases, carbon dioxide (CO2), is an important factor in scale deposition. Carbon dioxide dissolves in water to yield carbonic acid according to the following reaction: [CO2 + H2O - H2CO3 (carbonic acid)] Carbonic acid rapidly dissociates to yield bicarbonate and carbonate ions depending on the pH of the system: [H2CO3 -s H+ + HCO-3 (pH range 6-10) HCO3 -a H+ + COO (pH range > 9)] In gold cyanidation processes, lime is added to raise the pH of the mill solution to 10 or above to promote cyanidation of the gold and to eliminate the possibility of hydrogen cyanide (HCN) formation. Lime contributes both hydroxyl ions (OH--) and calcium ions (Ca++) to the solution. The normal scale forming reactions in mill water systems were described by Beasley (1973) as: [HCO-3 + OH -s C03 + H2O Ca++ + C03 -a CaCO3] Factor affecting scale deposition According to Linke's (1958) solubility tables, the solubility of calcium carbonate in carbon-dioxide free water is only 13 mg/dm3 (13 mg/L) at 25° C (77° F). Scale deposition occurs when the concentration of calcium and carbonate ions in the solution exceeds the solubility of calcium carbonate. This occurs, in most cases, when the water has undergone some chemical or physical change. Some typical changes that might occur that lead to scale deposition are discussed below. Temperature An increase in temperature can greatly increase the tendency to form calcium carbonate scale. Studies by Miller (1952) have indicated that calcium carbonate is less soluble at higher temperatures. Hence, high temperatures promote scaling. For this reason, scale is often noticed on heat exchangers, autoclaves and other high temperature surfaces. Pressure A decrease in pressure may lead to an increase in the tendency to form calcium carbonate scale. Fulford's (1967) work has shown that scale is more soluble at high pressures. Hence, scale is likely to be prevalent in pump suction lines, elbows, baffles and other areas that produce turbulence and subsequent pressure drops. Change in pH Calcium carbonate scale is pH dependent and tends to form more readily at high pH. Any event that causes an increase in pH, such as the introduction of lime or caustic, would tend to initiate scale formation. Since most gold recovery operations are run at a pH above 10, the tendency to form calcium carbonate scale is always great. The use of scale inhibitors to prevent calcium carbonate scale Many products are commercially available to inhibit the formation of calcium carbonate scale. Some of the more effective types include phosphonates, as well as acrylate and maleate-based polymers and copolymers. Many of these products function by means of threshold

Jan 1, 1992

By J. A. Barrera-Godinez

Traditional batch flotation tests produce a limited number of data points from which to evaluate the kinetics of the process. In this research, continuous weighing of froth, from a modified circular flotation cell, using a computer/data acquisition system., has been coupled with chemical analyses from intermittent froth sampling. This combination has permitted the experimental data to be smoothed such that the flotation kinetic parameters could be determined with enhanced confidence. To demonstrate the procedure, a galena ore was floated to permit flotation kinetics to be investigated as a function of cell parameters. It was shown that the kinetic data of this lead flotation most closely correlated with the Huber-Panu three parameter model. In addition the results illustrated the effect of froth thickness, froth scraper rate and air flow rate on the cell performance, in terms of mass flow, grade and recovery.

Jan 1, 1990

By P. Somasundaran, S. Venkatachalam, N. K. Khosla, K. Khosla

Froth flotation of alumina particles was studied by employing and hydrogen gas bubbles. The effect of current density was studied over a range of 0.1 to1.6 kA/m2. Compared to hydrogen, the use of oxygen bubbles at any given gas evolution rate resulted in a higher flotation recovery. The existence of an optimum current density, for each given particle size was indicated. Flotation at higher current densities resulted in better flotation kinetics, while flotation at lower current densities resulted in better Spas utilization.

Jan 1, 1996