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By David Akers, Clifford Raleigh, Glenn Shirey

Under a Cooperative Agreement with the U.S. Department of Energy’s National Energy Technology Laboratory (NETL) and the Mining Industry of the Future Program, CQ Inc. is demonstrating the GranuFlow™ process for improving the recovery of fine-sized coal in commercial coal preparation facilities. The State of Pennsylvania’s Energy Harvest Grant Program is also providing funding for this project. The GranuFlow technology involves the addition of an asphalt emulsion to a slurry of fine-sized coal (<100 mesh or 0.15 mm, typically froth flotation concentrate) before mechanical dewatering in screen-bowl centrifuges. The emulsion selectively agglomerates the carbon-rich particles, resulting in increased particle size and improved recovery of the coal fines during the dewatering process. This paper summarizes the test conditions and current results for both bench-scale investigations and full-scale commercial plant demonstrations.

Jan 1, 2005

By G. Reed Marchant

During the past two decades, we have witnessed the computer revolution. Like other revolutions, it has been successful in many ways; however, it has not been without difficulties. One of the areas where these difficulties have been more prevalent has been in the application of computers for the purpose of controlling industrial processes. During the early 1960&apos;s, many people naively assumed that bridging the gap between data processing and process control was a simple matter of connecting a few wires, doing a little programming, laying off most of the people and watching the plant make great increases in production as the lights on the computer blinked on and off. Unfortunately, it has not been that simple. Instead, a whole new-set of disciplines has been required to overcome the major obstacles that exist. Nevertheless, current successes are proving that the digital process control computer is here to stay, and that through the application of digital computers an attractive return on investment can be obtained in many applications.. The purpose of this paper is to illustrate some of the requirements for successful implementation of computer control systems, with particular attention to the following four objectives: First: Acquaint the reader with the general control problems so that he may more fully recognize the major requirements for successful implementation. Second: To acquaint the reader with the types of control hardware that can be considered for use in the development of control systems. Third: To discuss some of the major obstacles that must be overcome for successful implementation of computer control systems. Fourth: To discuss the systems approach in the development of control systems and to illustrate it in the implementation of an actual control system.

Jan 1, 1971

By D. M. Larsen, N. D. King

Since start-up in 1985, the Cannon Mine has produced and shipped a 170-g/ton (5 oz/ton) gold flotation concentrate to various smelters for gold and silver recovery. Several processes have been investigated to economically produce dore&apos; at the mine site from the refractory concentrate. This paper describes laboratory and pilot scale test work used in the process design and engineering feasibility study of a 73-t/d (80 stpd) pressure oxidation and carbon-in-leach (CIL) facility. The designed pressure oxidation circuit utilizes a series of vertical autoclave units operating at 170°C (338°F) and 1.4 MPa (200 psig). Projected operating costs are discussed.

Jan 1, 1994

By Jeffrey D. Swanson, Martin L. Smith

Smelterville Flats in Idaho&apos;s Silver Valley has been designated as a Superfund site due to metals contamination resulting from the use of the South Fork of the Coeur d&apos;Alene river as a tailings impoundment earlier in this century. Tailings average in excess of 4% lead and zinc. Selective mining of highly contaminated zones is being studied as one of several possible remediation strategies. The first step towards remediation is the examination of the stratigraphic, geochemical and spatial characteristics of the site. These characteristics are related to appropriate sampling protocols and exploratory sample grid design. Special problems involved in the geostatistical analysis of tailings are emphasized.

Jan 1, 1992

By Robert D. Gibson, E. Donald McKay, Paul B. DuMontelle

Subsidence of the land surface in some parts of Illinois is caused by underground coal mining. The U.S. Bureau of Mines is backfilling abandoned mines at selected sites in southwestern Illinois in an attempt to support failing mine openings. The Illinois State Geological Survey assists the Bureau by developing geologic and engineering information. As part of this investigation, television probes of fifteen injection borings in Belleville augmented conventional methods of study. The television probes of uncased sections of borings revealed several phenomena. Water erosion caused shale beds to slough, which partially filled some borings. Fractures caused by subsidence were identified, and excellent views of underground mine workings provided documentation of the mining method. The condition of mine timber was evaluated. Pack walls supported some openings. Both floor heave and roof fall were observed to be causes of failure in the mines.

Jan 1, 1982

The National Mining Hall of Fame and Museum (NMHF&M) will induct its the 2014 National Mining Hall of Fame Class on Sept. 13, 2014 during its 27th Annual Induction Banquet and Ceremony at the Westin Hotel in Denver, CO. Representing the domestic and worldwide metal production, education, and health and safety sectors of the industry, this year?s four inductees cover a diverse cross-section of the mining industry. Harry M. Conger III, Günther Franz (Frank) Joklik, Ellen Swallow Richards and Dr. Alfred Weiss will join 223 other mining industry pioneers when they are formally inducted into the National Mining Hall of Fame. They were selected for being visionaries, leaders and ambassadors, both within their own sectors and across the industry at large. Conger was a great role model and strong advocate within Homestake Mining Co. and among his industry peers on behalf of environmentally responsible, safe, profitable and high-performance operations. As chairman and chief executive officer, Conger was instrumental in revitalizing and rebuilding Homestake into an industry leader in technological advances and environmental protection. Through his contributions in exploration, project development and operations management as Kennecott president and chief executive, Joklik did much to strengthen Kennecott as a company and assisted in restoring the competitiveness of the U.S. mining industry. Richards is generally recognized as the founder of ecology. She was the very definition of a pioneer in such diverse fields as chemistry, geology and mineralogy, mining and metallurgy, environmental science, public health, home economics and education. Weiss was a true visionary in using quantitative methods and digital computers to aid mineral exploration, plan and design mines, operate mineral production facilities and integrate the disparate information resources throughout a mining company into a modern management information system. NMHF&M Board of Directors Chairman, Paul C. Jones, said, ?Again this year we are honored to be able to induct an outstanding group of deserving individuals who have made exceptional contributions to the mining industry in the United States. Included are two living inductees who have made significant contributions to management in the industry. One inductee was the first female graduate from the Massachusetts Institute of Technology, its first female faculty member and the first female member of AIME who had an outstanding career as a mineral investigator in the United States. Another inductee was a lifetime innovator in bringing digital technology into common use in our industry. Each of our 2014 inductees made significant and lasting contributions to our industry and are well deserving of becoming a member of the National Mining Hall of Fame.? The Hall of Fame Induction Banquet and Ceremony is a marquee event for the National Mining Hall of Fame and Museum each year. The 27th Annual Induction Ceremony and Banquet will be held at the Westin Hotel in Denver, CO on Saturday, Sept. 13, 2014. For banquet reservations, contact the NMHF&M office at 719-486-1229. More information is available on the NMHF&M website at www.mininghalloffame.org.

By W. Irwin

As a consequence of the oil crisis of the 70?s, the commercial value of coal increased very sharply and an upward trend in coal prices although now less pronounced, continues today. The graph shown in figure 1 illustrates the trend in the F.O.B. price of U.S. metallurgical coal. This trend occurs during a time when mechanized mining is firmly established as a means of production throughout the coal mining world. With modem methods of mining, mechanical cleaning is a necessity and quality control is no longer entirely dependant upon coal face practice. The efficiency of fine coal recovery is of vital economic importance to present day operations and good practice in this field contributes significantly to improving profitability. Numerous processes are available for the duty and this paper discusses one such system, namely the practice of froth flotation.

Jan 1, 1980

By G. E. Erdman

The total attitude of the industrial minerals producing company is a most important factor in how they regard quality control, technical support for their customers, and procedures used in mining their minerals products. This philosophy of the producing organization directs their action along certain courses. For instance, one producer might see itself as a mining company with its major goal mining efficiency to make it exceedingly price competitive in the market place. Another producer might see itself as a wide spectrum multi-mineral producer that furnishes a reputation for a complete line of products. Another producer might see itself as a specialist in one specific industrial mineral and bet its whole bankroll on providing the very best of quality with the goal of becoming the largest producer of the mineral commodity. Each perception can have a different impact upon the producer&apos;s operations and its regard for quality control. Minerals Being Produced The specific markets being served will have their own influence on how mineral product quality is regarded. Ceramic raw materials, for instance, have a very low tolerance for iron which is the cause of low fired color. Thus, industrial minerals for use in glass and ceramic markets must be won from deposits with a very low iron content. A high iron silica sand might be sold to a manufacturer of good old beer bottles. That is a solution to one particular quality facet, but eliminates selling to a significant market in clear glass, porcelain enamel, ceramics whiteware bodies and hobby glazes. Thus, there is a need for sound research in the industries expected to be served before the product is brought to market.

Jan 1, 1987

By D. Tao

More than 80 million metric tons of fly ash is produced annually in the U.S. as coal combustion by-product. Fly ash can be converted to value-added products if unburned carbon is reduced to less than 2.5%. However, most of fly ash is currently landfilled as waste due to lack of efficient purification technologies to separate unburned carbon from fly ash. A rotary triboelectrostatic separator has been developed and patented recently at the University of Kentucky with unique features. Several fly ash samples have been used to understand the effects of major process parameters on the separation performance. The results show that compared to existing triboelectrostatic separators, the rotary triboelectrostatic separator has significant advantages in particle charging efficiency, solids throughput, separation efficiency, applicable particle size range. Key words: Coal, Combustion Waste; Fly Ash; Particle charging; Separation.

Jan 1, 2008

Mining at Hudson Bay Mining & Smelting&apos;s (H. B. M. & S.) Snow Lake Division is now in the mature stage of the mines lives. These base metal copper-zinc mines have been operating for over 30 years. Stopes had small pillars called "crown pillars", left between them. These pillars range up to 100 meters long by 40 meters wide and 15 meters thick. H. B. M. & S. has been successful in removing these pillars through the use of cable slings, electric scoops, longhole mining and diesel LHD equipment. The different shapes and sizes of these pillars has meant that many innovative techniques have been tried in order to find acceptable economic mining methods. An overview of the different methods will be outlined.

Jan 1, 1992

By L. F. Zeiler

In the past, health concerns in coal mines have primarily centered on those elements which have been essentially inherent to the mining environment. These would include respirable coal mine dust, respirable crystalline silica, excessive noise levels, and diesel exhaust particulates. Commercially-available chemical products are prevalent on mine property. These potentially toxic materials are chemical formulations that can degrease, clean, and lubricate metal parts, separate coal from rock in float/sink operations, and aid in roof consolidation, among other uses. As the general public has become more aware of the hazards of chemical exposures, miners have likewise become more concerned about working with an ever-expanding variety of chemical products on the job. Often, product or chemical specific hazard communication training is inadequate or ineffective, and miners do not know exactly what the ingredients are in the products they handle, or the health hazards involved with their use or misuse. Currently, the Mine Safety and Health Administration (MSHA), by law, enforces 1972 Threshold Limit Values (TLV). MSHA is making preparations to adopt new personal exposure limits for enforcement. The values given throughout the article are 1994 TLV&apos;s and are not enforcement standards, but are used for discussion purposes. They reflect the current scientific thinking regarding personal exposure to these chemical agents. An overview of these products is presented, and the potential health hazards associated with their use are discussed. Controls needed to prevent overexposures, such as proper handling procedures and personal protective equipment, are covered. Methods used to collect and identify contaminants are presented.

Jan 1, 1995

By M. L. Leming

The mechanisms of Alkali-Silica Reactivity (ASR) are briefly reviewed, test methods are examined, and typical specifications are discussed. In addition, views on responsibility of the aggregate supplier regarding specifications are presented.

Jan 1, 1995

By Ronney Rodrigues Silva, Renata Mendonca, Gabi Knesel, Cathrine Monyake

Locus Mining is working side-by-side with a prestigious iron ore company to evaluate the addition of Locus ESG-friendly green flotation reagents with the primary goal of improving recovery and grade. In this paper, we will focus on the cationic reverse flotation application. The most “established industry” reagents for cationic reverse flotation are amine as the collector, starch as the depressant, and in some cases frothers are also used (among them MIBC, pine oil, others). Here, we evaluate the synergies of different classes of eco-friendly biosurfactants and industry-standard reagents during the cationic reverse flotation method. Exploratory research was done first with an analog sample under different pHs, eight different biosurfactants with starch and no-starch, and a customized DOE was used to perform 145 microflotation tests. The results show Separation Efficiency from 20% (baseline) to 50% (biosurfactant), and Selectivity from 3.27 (baseline) to 5.67 (biosurfactant). Optimized result conditions were then applied to the iron ore samples received from our client to perform flotation tests on a Denver Lab cell. Similar results were obtained by improving Separation Efficiency and Selectivity, which corroborate with the previous work.

Feb 1, 2025

By Dan Norrgran

In recent years, a great deal of attention has been focused on developing mill liners to increase wear resistance, improve grinding efficiency and reduce energy consumption in milling applications. The installation of an appropriate mill liner is critical as it affects the overall cost and product quality. A mill liner has two specific functions. The first is to protect the mill shell and mill ends from direct contact with the abrasive grinding media (in this case, the liner serves as a wear surface). The second function is to transport the grinding media, creating energy for size reduction. The liner acts as a lifter, mechanically transporting and cascading the grinding media. The mill lining is a major cost in the milling operation. The costs associated with the mill lining include the capital cost of the lining, downtime required to replace the worn liner and the labor for installation. Generally, in hard rock mining, the life of a mill liner in secondary ball mills is 12 to 24 months.

Jan 1, 2009

By David G. Van Hersett

The single most unique design feature of the Centralia Coal Mine is the public information program. Just what the heck does public information have to do with the development of a coal mine? The utilities of today have had to build larger and larger plants to keep down the costs of power to the consumer. The large plants require huge amounts of capital, take up large areas of real estate, consume unprecedented amounts of coal, and generate large quantities of waste products which have to be reckoned with. Coal mines supplying these plants have also increased in size and production to meet the power plants&apos; unending appetite for coal. This means the disturbance of great areas of land and significant alterations to the landscape. Today&apos;s public is greatly concerned about the environment in which he is living. The great size of a power plant with its large stacks, coal piles, and the coal mine with its large earth movers, disturbed acreages and the resulting waste products of both operations appears to present a threat to his environment. Because of this,&apos; many power plants and coal mines are having public acceptance problems. This has resulted in the passage of stringent legislation and in some cases brought upon construction delays for major power plants.

Jan 1, 1970

By H. Boyd

Fluid energy grinding, or jet pulverization, refers to the process of entraining solid particles in high velocity gaseous or vaporous streams and reducing their size by impact and attrition against other particles or some sort of target. Since all desired size reduction is not achieved in one pass through the zone where energy is applied, some form of classification is necessary to return oversize particles to the grinding zone for further size reduction. Applications Fluid energy mills have normally been used to produce products where the particle size is basically finer than 325 mesh. Products having particle size distributions with a maximum size of 4 or 5 µm, and with a high percentage finer than I µm, can be produced using fluid energy mills. More recently, some fluid energy grinding units have been applied economically to produce ground products with 1 or 2% coarser than 200 mesh. It is also possible to consider usage of a jet-pulverizing zone, without the usual integrated air classi¬fier, operated either in open circuit or in conjunction with a screen. Feed sizes to be delivered to the fluid energy mill depend on the material involved, the type of jet pulverizer used, the finished product size requirement, and the upstream process. In some units feed sizes up to l in. or larger can be accepted, but practical economics usually require the starting material to be -4 mesh or smaller and some pulverizers are typically fed at 20 mesh top size. It is not unusual to find feed materials at essentially -325 mesh when extremely fine products are needed, since capacities are improved with finer feeds. Conventionally the fluid energy grinding process has been used for relatively soft and nonabrasive materials. This includes very low¬melting-point and temperature-sensitive materials or coatings, since there is no measurable temperature rise during fluid energy milling. More recently, however, jet pulverizers are being used on highly abra¬sive materials such as silica, feldspar, glass, zircon, calcined alumina, coke, boron carbide, and similar materials. Since the primary energy application is by impact of particles against themselves, there is a low rate of wear resulting in a small amount of product contamination and in low maintenance costs. Usually the fluid energy pulverizer produces a more narrow particle size distribution than other mills provide, and this is useful where such a requirement exists. It is possible, within limits, to adjust classifi¬cation and other functions of the overall fluid energy system to vary the particle size distribution curve and thereby approach the broader distribution obtained from other grinding methods. By controlling the temperature, composition, and humidity of the fluid used, it is possible to incorporate other functions with the size-reduction process. These include drying or adding moisture, coating, mixing and blend¬ing, and even oxidation or reduction and other chemical reactions or their inhibition. The finished product is discharged in the fluid stream and is conveyed pneumatically to the desired point, where a suitable dust collector must be provided. Operation and Mechanical Features One of the earliest fluid energy mills is the Micronizer now manu¬factured by the Sturtevant Mill Co. Similar units are also manufac¬tured by Jet Pulverizer Co. and others. As shown in Fig. 81, the micronizer consists of a shallow circular grinding chamber with noz¬zles arranged at the outer periphery to discharge tangentially inward. Fluid (usually compressed air or superheated steam) is provided to the nozzles from a manifold at pressures normally in the range of 100-150 psig and at temperatures up to 800°F or higher, depending on the raw material, required results, and economic factors. The com¬pressible fluid expands to high velocity through the nozzles and gener¬ates a spiral flow pattern in the grinding chamber, and discharges

Jan 1, 1985

By Myles E. Altimus

One responsibility of a manager is to improve his human organization. Some executives believe a manager should be measured and compensated accordingly on the basis of his ability to improve the quality of his human organization. Officials in the coal mining industry have had a tough road to travel in this regard due to fluctuating coal production demands, contractual obligations, and improved mining equipment and methods. The time may have finally arrived when we are able to recruit, select, and develop men from the labor market to fill vacancies, This is particularly true of our maintenance organizations. Because of the importance of this responsible function and the types of skills required, we must develop an extensive improvement pro- gram. Anyone in the industry who fails to undertake a manpower audit and who accepts a philosophy which will not permit collective planning, organizing and con- trolling the improvement of the human element throughout his maintenance organization may certainly cause deterioration within his company.

Jan 1, 1966

By H. Sevim

Long term production planning in open pit mines requires the determination of cutoff grade, mining and milling production rates, mining sequence, mine life, and ultimate pit limits. These variables interact in a circular fashion, that is, the value of a variable can not be determined without the knowledge of the value of the preceding variable in the circle. Therefore, a genuine solution to the problem necessitates simultaneous determination of the variables. Such a solution methodology, comprised of a group of heuristic algorithms and an unconventional dynamic programming algorithm, is described in this paper. The methodology is applied to a small size Western US gold deposit to illustrate its logic and capabilities.

Jan 1, 1995

By Jacques H. Nantel, James F. Archibald

INTRODUCTION The use of backfill materials in underground mines has been practiced for many years and the trend indicates an increased utilization of backfill materials in the future. The authors believe that underground uranium mines will follow this trend. Classified mill tailings, approximately 65 to 70 percent solids by weight, are the most common fill materials. Cement or other pozzolanic agents can be added to the fill materials to improve their strength characteristics. Dry fill, in the form of development muck, can also be introduced in the stopes to fill the voids left by the action of mining the ore. This paper deals mainly with the assessment of the radiation properties of backfill materials originating from uranium ores processed in the milling facilities of uranium mines. The paper outlines the results of studies conducted in the laboratory and in the field on radon emanating characteristics of backfill materials utilized in uranium mines. ROLE OF BACKFILL IN UNDERGROUND MINES Fill is a structural component of any underground mining system. In general terms, the purpose of filling is to provide ground support, to make recovery of pillars possible to provide a working platform for men and equipment, and to allow for waste disposal. There are other inherent advantages to the use of backfill underground, the most important being to: a) permit mining at greater depth b) allow the adoption of highly mechanized mining techniques c) reduce dilution from wall sloughing d) minimize roof and wall failures e) allow the mining of irregular orebodies, and f) to provide better control of ventilation. The last item is of great importance to uranium mine operators. The introduction of radioactive backfill underground represents an additional source of radioactive contamination; on the other hand the introduction of backfill in the mine reduces the volumes of workings to be ventilated. As a consequence the general mine ventilation is more effective and in most cases, better air quality can be maintained in the mine. There are of course some disadvantages associated with the use of hydraulic fills in underground mines, notably: a) the handling of large additional quantities of water from the underground workings b) delays caused by the cyclical nature of the backfilling operations c) additional costs associated with stope preparation and placement of backfill in stopes, and d) "spills" caused by bursting pipes or fill escaping from fill retaining structures. ASSESSMENT OF NON-RADIOACTIVE PROPERTIES Although the radioactive properties of mine backfills are discussed in this paper many other physical and chemical properties of backfills must also be considered. These properties include: a) percolation rate and permeability parameters b) viscosity versus pulp density relationships c) size analyses d) settling times e) settled bulk density f) solids specific gravity g) void ratio and porosity h) optimal percentage solids by weight i) specific gravity of slurry j) addition of cement:cement retention and loss k) unconfined compressive strength 1) triaxial compressive strength m) shear strength (non-cemented)

Jan 1, 1981

By A. Halim, J. Gustafsson, A. van Wageningen, J. Johansson, · J. Lööw, K. Kocsis

A major part of the European Union’s (EU) project Sustainable Intelligent Mining System (SIMS) is investigating the development of diesel-free/carbon–neutral underground mines in order to ensure sustainable underground mining in the future. Replacing diesel machines with electric vehicles in underground hard rock mines has been widely acknowledged by the mining industry worldwide as a critical step to improve working conditions by reducing diesel exhaust–related contaminants, to reduce mine ventilation electrical power cost by reducing mine airflow quantity, and to reduce mine greenhouse gas emissions. All of these are major requirements to achieve sustainable future underground mining practices. A field trial of Epiroc’s 2nd generation of Battery Electric Vehicles (BEVs) at Agnico Eagle Finland’s Kittilä mine was conducted during 2019–2020. Vehicles tested were MT42 mine truck, ST14 Load-Haul-Dump (LHD), and Boomer E2 jumbo drill rig. This paper outlines the improvement of the working conditions observed in the field trial, and the opinions of the mine personnel at Kittilä mine on using BEVs instead of diesel machines. Measurements of atmospheric contaminants and air temperatures taken during the field trial clearly demonstrated a significant improvement of working conditions when BEVs were operating as opposed to diesel machines. This field observation was supported by the opinion of the majority of the Kittilä mine workers. However, some remaining concerns must be addressed before BEVs can replace diesel machines.

Oct 25, 2021