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By Ernest M. Spokes

Starting in 1980, a committee of the National Research Council studied the question of why some underground coal mines are safer than others and what could be done to improve the ones with poorer performance. The results indicated that safety is improved by management commitment to safety, by cooperation between labor and management on safety matters, and by quality training of employees and managers. Younger mines have higher accident frequencies, but are less likely to be killed or permanently disabled by a lost-time accident. Methods for improving safety performance are proposed.

Jan 1, 1983

By R. R. Klimpel

The use of froth flotation as a means of separating and upgrading sulfide mineral concentrates is standard industrial practice throughout the world. Froth flotation is also widely recognized to be a very complex system having highly interactive and often self-compensating factors at work. Several summary articles have been recently published which discuss at length some of the important practical aspects of optimizing the use of existing commercial flotation reagents. Klimpel (1987). Klimpel and Hansen (1987a), Klimpel and Hansen (1987b), and Klimpel (1988). It is apparent from monitoring the industrial practice of sulfide mineral flotation over the last decade that considerable progress has been made in optimizing the operating aspects of flotation. For example, the availability of improved instrumentation and related computer devices, modified mechanical flotation cell designs, better reagent dosage control leading to less reagent usage per ton of ore, blending of feed ores, more attention to coarse and fine particle flotations, etc., are all examples of this progress.

Jan 1, 1988

By Mark E. Emerson

Foreign and domestic companies find the mineral potential of this country's stern public lands, its capital markets, political stability, and "open-door" policy attractive for hard mineral exploration. Traditionally, exploration in the US has been geographically based and responsibility oriented at the district level. The 1970s brought a decentralized approach to exploration as major non-metal companies began to diversify into hard minerals. The emphasis was on capital intensive metal and energy projects involving bulk-tonnages. The recent economic downturn in metals has caused many of the new participants to withdraw from the mineral scene. The surviving companies have shifted their emphasis toward medium scale precious metal projects having high operating margins and rapid return on equity. Exploration expenditures in the United States are now principally focused on gold and silver to the exclusion of practically all other commodities. In the search for precious metals companies have scaled back their exploration efforts and have began to apply new approaches to target selection. The search is being assisted by rapidly evolving conceptual models. The change in orientation has led to numerous new discoveries. The finds are essentially "rediscoveries" that c,-re previously uneconomic. The majority are low-grade surface deposits that have involved low discovery costs and short lead times for development by low-cost mining and beneficiation methods. The emphasis on gold to the exclusion of all other commodities raises questions regarding the direction of exploration in the US for the rest of the 80s.

Jan 1, 1984

By B. T. Lusk, Q. Q. Huang, R. Q. Honaker, K. A. Perry

Rock dust is applied in underground coal mines to prevent the propagation of coal dust explosions. It is applied either dry or wet. Both methods have advantages and disadvantages, but the formation of caked rock dust particles is cited as a significant concern for wet applications. We conducted a study to evaluate the effect of modifying the rock dust particle surfaces to repel water and each other by the addition of oleic acid and sodium oleate. At a sodium oleate dosage of 1 kg/t, a contact angle of 112o was measured, indicating strong surface hydrophobicity and thus the ability to repel water. Fourier transform infrared spectroscopy (FTIR) studies indicated a chemisorption mechanism, which is necessary for long-term stability of the surface modification. The dispersibility of the modified rock dust samples was elevated by the application of both oleic acid and sodium oleate, thereby indicating a significant reduction or elimination of the detrimental effect of caking. Tests in an explosion chamber showed an 82.8 percent reduction in the dust explosion potential relative to untreated rock test applied by the wet technique.

Jan 1, 2015

By Courtney Chamberlain

The Telfer Project, Australia's newest, largest and most remote gold mine, treats 480,000 metric tonnes of ore grading 9.33 grams per tonne derived from open pit mining operations. Coarse gold is recovered by gravity concentration with jigs and further upgraded using a continuous strake, table and by amalgamation. Remaining gold is recovered in a cyanide circuit and incorporates flat bottom air agitators, CCD and stellar filters for clarification and precipitate removal. Overall recovery into bullion averages 98 percent. The mill incorporates a number of design features which allow for maximum efficiency and security using a minimum number of operating personnel.

Jan 1, 1980

By D. S. Davies

Further development of the Nitric-Sulfuric Leach (NSL) process has led to an improved design of the leach and nitric acid recovery steps. NO produced in the leach step is reacted with oxygen, regenerating N02, which is sparged directly into the leach reactor. Leaching is simplified to two steps and the nitric acid plant is replaced with an oxidation recycle gas sys-tem. Laboratory work substantiated the concept and led to selection of operating conditions. The lab work also pointed to improved process control compared to use of nitric acid as the sole oxidant. Recovery of copper from purified pregnant liquor is modified to use air agitation electrowinning improving cathode quality and lowering tankhouse costs. Economic evaluation shows reduction of capital requirements from $2400/AT to $2000/AT in 1978 dollars for 50,000 TPY of copper production.

Jan 1, 1978

By Yves Boissonnas, Marco Bettelini

"INTRODUCTION AND OBJECTIVES The operational safety of long and very long rail tunnels represents a key issue in all development stages, including design, construction, commissioning and operation. The spectrum of potential threats is very broad and challenging. These issues can only be mastered by means of a proper combination of a number of safety measures at various levels. This paper focuses on the specific safety issues and the extremely challenging conditions characterizing very long and deep tunnels. They include a significantly increased risk during operation that the incident train cannot exit the tunnel by its own means, long self-rescue and rescue distances, the presence of a number of trains, possibly mixed traffic as well as significant thermal issues. Amberg Engineering is strongly involved in the design and construction of most long and very long rail tunnels in Europe, including in particular the Gotthard Base Tunnel (GBT), Lyon-Turin Base Tunnel (LTF) and the Brenner Base Tunnel (BBT). The combined experience arising from these tunnels forms an invaluable body of expertise, which is summarized in this paper. The focus is on shared issues with practical relevant examples and project-specific solutions. Special attention will be devoted to the 57 km long Gotthard Base Tunnel, which will be operational by mid-2016 and will be the longest infrastructure tunnel worldwide. VERY LONG TUNNELS IN EUROPE Overview From the point of view of safety, tunnels in excess of about 20 km exhibit a significantly increased risk that incident trains could stop within the tunnel. This is related to the European Technical Specifications for Interoperability (TSI) on rolling stock, to be discussed in the chapter on rescue stations. This paper will specifically focus on the following longest tunnels in construction or operation, listed in Table 1."

Jan 1, 2016

By Sarkis G. Ampian

This late 1979 Bureau of Mines report presents current stocks and monthly consumption rates for Guyanese refractory bauxite (GRB), with emphasis on the impact of the GRB shortage on the refractory and downstream industries, general background material, and an evaluation of the situation resulting from the strike of Guyanese bauxite workers during the summer of 1979. A study by the Bureau indicated that industry stocks contained little more than a month's supply of GRB--30,000 calcined short tons (CST), at present consumption rates of 25,000 CST per month. The report was requested by the Federal Emergency Management Agency (FW) in response to refractory industry requests that the Government release GRB from the National Stockpile to minimize forecasted industry problems. The report traces the historical innovations in the high-alumina and/or bauxite-type refractory products industry, eventually leading up to fabrication of modern, high-quality firebrick and monolithic refractories.

Jan 1, 1980

By R. Bruce Thorndycraft

Pinson Mining Company was formed to develop a gold orebody located in northern Nevada near Winnemucca. A feasibility study was undertaken in 1979 by a consortium of three Toronto-based mining companies and a Reno-based exploration company. The study indicated a viable project with gold priced above $225 per ounce. A project manager, and mine and mill superintendents, were hired in late 1979 to expedite the development of a 1000 ton per day mine-mill complex. Plant design engineering was contracted with Industrial Design Corporation in Salt Lake City. Three experienced plant metallurgists representing Pinson were stationed in Salt Lake to guide the work of Industrial Design. Among the many design criteria spelled out by Pinson, foremost were bringing the mill on line as quickly as possible at minimum capital cost. Fourteen months after the beginning of design engineering, the completed Pinson mill became operational. Total capital cost, including mine development, was $18 million. The Pinson project has proved to be far more than viable; the entire capital cost will be recovered within 18 months of the mill start-up.

Jan 1, 1982

By Quansheng Li

Large-scale coal mining will cause environmental problems such as aquifer damage, land excavation and occupation, soil erosion, vegetation damage, and regional landscape damage. The existing coal mine environmental restoration technology is relatively simple, and there is a lack of systematic research on environmental total factors. Based on the mechanism of coal mining damage and the laws of environmental natural succession, the concept of “coal environmental protection mining” is proposed, which combines damage reduction mining and environmental element system restoration. In accordance with the environmental protection principle of “source protection, process damage reduction, and systematic restoration,” a technical system of “coal environmental protection mining” is constructed for the two types of mining damage scenarios: underground mining and open-pit mining. In view of the damage characteristics of underground mining, source environmental protection technology based on optimization of mining process parameters, stability maintenance and damage reduction technology for overlying rock bearing arch shell structure, zoning and time-sharing treatment of surface cracks, and direct drainage irrigation technology for mine water have developed. In accordance with the damage characteristics caused by open-pit mining, land-saving and source reduction damage technology, near-natural stratigraphic reconstruction, topsoil improvement, and environmental storage and utilization technologies for seasonal precipitation have developed. By applying the technology in this paper, the maximum surface settlement value of 12401 working face in Shangwan coal mine was relatively reduced by 25%, the surface cracks have been adjusted from step-type cracks to dynamic small cracks, and since the technical implementation of the Shendong mining area in 2010, the vegetation coverage has increased loss and crushing decreased by 0.06 km2 every year, the environmental restoration period of the dump site was advanced by more than one year, and the vegetation coverage rate increased by 41.78% compared with the background value in the semi-arid area of the victory open-pit coal mine demonstration area. A surface reservoir with a water storage capacity of 400,000 cubic meters has been built, and the seasonal and graded utilization of mine water has been realized. An underground reservoir with a water storage capacity of 1.22 million square meters has been built in the Baorixiler open-pit coal mine.

Jun 25, 2024

By S. Anderson

Advances in inexpensive computer automation led to the development and utilization of a computerized ore control system at Cyprus Coppers tone Gold Mine near Parker, Arizona. These new ore control practices improved accuracy, performance, and productivity of the ore control effort. An automated system for data collection, including bar coding of blast hole samples, laboratory analysis, data management, grade estimation, cut delineation, and ore zone stakeout, plays a major role in ore control practices. This is of particular interest because of the large amount of blast hole information being processed, analyzed, and reported daily.

Jan 1, 1991

By Frank C. Schora

The Institute of Gas Technology for many years has dedicated a large portion of its research effort to the development of a practical solid-fuel-based gasification process to produce a synthetic natural gas equivalent. The work is being done to prepare for the day when supplemental gas will be needed. This program, initially supported by the American Gas Association, and now by both the Department of Interior's Office of Coal Research and the American Gas Association, has developed the IGT Hydrogasification Process. This process, now entering the pilot plant stage, is based on the high-temperature, high- pressure hydrogenation of coal with a hydrogen-steam bearing gas. Product gas from this step is cleaned and catalytically methanated to produce a high-Btu gas. Estimated production costs indicate the process will be competitive with natural gas in certain areas of the country when required.

Jan 1, 1969

By J. Y. Hwang

Coal cleaning with traditional magnetic separation usually yields unsatisfactory results because minerals associated with coal, such as quartz, clay, pyrite and calcite, are weak-or non-magnetic. Magnetic reagent technology is a new mineral processing technology with the capability to enhance the magnetic property of minerals selectively. This reagent can be adsorbed selectively on minerals through the control of surface chemistry and, thus, result in selective magnetic enhancement. The application of this technology on coal cleaning has been experimentally demonstrated. Good separation results can be obtained at low to medium magnetic field strength. Comparison with other processing technologies is included.

Jan 1, 1992

By C. Haycocks

The evolution of longwall mining is briefly traced from its inception in England in the 1620's. In the beginning this method recovered 90% of coal with roof closure controlled by packs and walls. Mechanization began with kerf cutting, crude face conveyors, and improved face support. Full face mining was accompanied by the introduction of self-advancing hydraulic supports. U.S. longwalls evolved a retreating system to recover blocks of coal outlined by room and pillar panels. Computer control combined with the most modern technology has greatly increased productivity. Past trends are used to predict future technological directions.

Jan 1, 1997

By Michael A. Trevits

The National Institute for Occupational Safety and Health (NIOSH) in partnership with Strata Products tested the sealing capability of Ventstop®? as part of an ongoing mine fire control and suppression research program. Ventstop®? is a multi-purpose, inflatable device that is produced by Minvent Solutions and is available world wide for use in the metal and nonmetal mining industry. Ventstop®? is also used in the Australian coal industry as a temporary ventilation control device. The device can be quickly deployed, is reusable and can be placed in horizontal and vertical mine voids to control dust, fumes and smoke. Deployment, multi-day inflation and air leakage tests were conducted at the NIOSH Lake Lynn Laboratory to determine the capability and limitations of Ventstop®? in a simulated coal mine setting. During the tests, Ventstop®? was also subjected to low level forces of a nearby methane gas ignition. It is thought that Ventstop®? could be used by the US coal mining industry to temporarily close an underground mine area in response to a fire or spontaneous combustion heating event, to temporarily redirect mine ventilation during longwall equipment moves or during stopping construction. This paper describes this inflatable temporary mine sealing technology and presents the results of the NIOSH tests.

Jan 1, 2009

By J. T. Clancey

The potential inadequacy of natural gas reserves to supply projected requirements in the 1980's has been pointed out.(1,2) As a result, interest has arisen in the development of new, potentially low-cost processes for the conversion of coal into high BTU gas. In June, 1964, the office of Coal Research (U. S. Department of interior) and Consolidation Coal Company (now a subsidiary of Continental Oil Company) entered into a contract to continue work on coal gasification utilizing the Consol CO2 Acceptor Process. Work under this contract has been specifically directed toward the use of lignite as the carbonaceous feed, although the process is also applicable to non-caking subbituminous coals. The primary objective of this work was to establish the technical feasibility in continuous bench-scale equipment, of the novel features of the C02 Acceptor Process. Secondary objectives were the testing of commercially obtainable acceptors and the design and economic evaluation of a commercial facility. The bench-scale process development has been completed successfully and the construction of a large pilot plant at Rapid City, South Dakota, has been authorized. It is the purpose of this paper to review the technology of this new gasification process and to present the current projected economics of a plant producing 250 MM SCFD of pipeline quality gas.

Jan 1, 1969

By J. R. Batista

Leachates from gold heap-leaching mines contain selenium concentrations as high as 2 mg/L. Previous studies report satisfactory selenium adsorption by activated alumina when using relatively "clean" drinking waters. However, the findings of these studies cannot be directly applied to the treatment of mine leachate where other ions compete for the alumina adsorption sites. This study evaluated the adsorption of selenium from a mine leachate to develop design parameters for full-scale activated alumina processes. The study revealed that 68% of the selenium in the leachate could be removed by alumina at pH > 5.0. Silica adversely affected the selenium adsorption capacity. At pH values < 4, silica was poorly adsorbed by alumina and selenium adsorption was improved.

Jan 1, 1994

By Steve Kral

The mining industry has waited a long time for the resurgence in commodity prices and demand for its products that it is now experiencing. Base and precious metals prices have reached levels not seen before. Coal prices have also shot up. And there are encouraging signs in the uranium market. China’s nearly out-of-control economic growth is said to be the leading driver for much of this resurgence. But demand for energy, metals and building materials in the United States and elsewhere are also major factors. The result is that expansions and new mines for nearly every commodity are in the works.

Jan 1, 2005

By M. Javier

"The impact of mine closure is perceived through a veil of compliance to human laws and regulations rather than the laws and equilibrium of nature. This perception motivates present research. Understanding the causes and effects of mine closure defines levels of responsibility. This understanding evolves from mine closure&apos;s legacy. Mine closure is characterized in perpetuity by three aspects: Future liabilities; level of technologies for extraction and, usage of mineral resources. These aspects must be updated to a rationally appropriate level. This paper will address the following questions: Will the minerals remaining in the process of mine closure ever be recovered? Will the mine closure inhibit the availability of minerals for the next generation? How many mines are designed to perform a successful mine closure? Do we close the mines or do we close nature? Is it responsible to continue mine closures as we do them today? Is mine closure a complement of mine operations or a contradiction of mining? Do we need to perform mine closures, yet? This paper reviews mine closure practices and principles with the level of responsibility to nature and for the next generation.PREFACE The planet has irreversible issues to deal with regarding the depletion of mineral resources and contamination occurring from human activities. The population increased exponentially to more than seven billion, this high population with its lifestyles, demands a higher supply of minerals. In spite of these conditions, mining is a vital industry to keep ""civilization"" in society. This is evidenced by what we see around us, in that everything ""made"" in society is directly or indirectly due to mining. Hence, mining cannot be avoided or ignored. Society misunderstands the importance of mining in relation to other activities. At this time, mining is fragmented and economically oriented to supply cheap minerals to a market with peculiar characteristics regarding products that could be designed for recycling and stimulate nature’s equilibrium. These issues add important “variable factors” to the equation, when they are considered as parameters for the next generation. It also raises many questions regarding principles and attitudes about morals and ethics exercised in all anthropogenic activities. The industry&apos;s practices have many flourishing paradigms which are subject to a variety of criticisms and observations. Some of these observations will be described in this paper. It is important to clarify in advance a ""normal disclaimer"" about the ""apparent contradiction"" that could take place in the writer&apos;s comprehension when we abruptly ""jump to conclusions"". We must remember that we are profiling the future in an arena that demands a better understanding of solutions to problems created by actual mining."

Jan 1, 2015

By C. C. Hatch

As part of a general project to simulate a concentrator, the Brenda Mines Limited secondary crushing plant, located near Peachland, B. C., was sampled during the summer and winter of 1975 to develop a digital crushing plant simulator specific to the Brenda operation. The purpose of this simulator was to study the influence of manipulable process variables on important responses and to permit study of alternative circuit configurations if desired. This paper describes the simulation methodology employed and presents the results of a computer study of the secondary crushing plant (1).

Jan 1, 1979