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By Ronald D. Hill

The occurrence of acid mine Drainage (AMD) with coal mining has been well documented. (1) Less documentation is available of its association with other types of mining, e.g., copper, gold, zinc, and sulfur. Yet there are many locations in the western states where acid mine drainage is as great a pollution problem as in Appalachia and in some cases, because of the high copper, zinc, and arsenic concentrations, they present an even more difficult problem. Until a few years ago, it was generally believed that the neutralization of acid mine drainage was uneconomical thus, AMD was allowed to discharge freely into our streams. However, the demand for good water finally dictated that the mining industry be included under pollution laws. In 1964 the Commonwealth of Pennsylvania passed a law requiring that all active mine discharges meet a discharge standard of pH 6-9, iron less than 7 mg/1, and the water must have a net alkalinity. Several other states now require active mines to treat AMD. In all but a few cases, lime neutralization, often in conjunction with aeration, has been the treatment method used. The high cost of lime as compared to limestone and the poor quality sludge, (slow settling, large volumes, and low solids content) has stimulated work in the utilization of limestone. This paper reports on the current state-of-the-art of limestone treatment of AMD.

Jan 1, 1970

By JAMES J. PURDY

The great majority of stokers used in residential heating installations are of the clinkering type. Because of inherent characteristics of the under- feed combustion process as it occurs in these small stokers, and because of the wide range of operating conditions encountered in residential heating schedules, not all bituminous coals can be used successfully in residential underfeed units. The problem of providing consumer satisfaction has been attacked by the joint efforts of the stoker manufacturers and the coal industry; the stoker manufacturers have been concerned with improving their product to permit the use of a wider range of coals, and coal operators have made every effort to market selected and better prepared coals. In view of the wide range of physical characteristics and chemical properties of bituminous coals, the problems are real and are receiving increased attention.

Jan 1, 1949

By B. A. Kennedy

The instrumentation, monitoring, and prediction of a major slope failure at the Chuquicamata mine are described. In December 1967, pre-existing tension cracks on the south end of the east wall of the Chquicamata mine began to open. Various forms of instrumentation were installed for continuous monitoring. These systems included tension crack stakes, crack extensometers, linear extensometers, tape and transit lines, sliding wire contacts, and a seismograph. From the information obtained, the failure date was accurately predicted some five weeks before failure, enabling the mine to reroute truck and rail access; hence, causing a minimal mine shutdown of two and one-half days and preventing any injuries to persons or damage to equipment. The shape and form of the sliding mass are analyzed, as are the possible modes of failure.

Jan 1, 1970

By Kurt Tischler

This paper presents the field experience of Siemens with regard to Gearless Drives in the mining industry ? We consider the elapsed production hours of Siemens Gearless Drives to be extensive enough to provide a reliable estimation of availability calculated on the basis of data representing repair time, downtime, and operating time. The users of Siemens Gearless Drives confirm an availability of more than 98% after exclusion of some major issues. The paper addresses all of these major issues of Siemens Gearless Drives, describes successfully applied corrective measures, explains the influences on the design of the drives, and lists the downtimes associated with each of these issues.

Jan 1, 2012

By Albert L. Toenges, Louis A. Turnbull, Alonzo W. Quinn, J. M. Schopf, Arthur Neale, R. F. Abernethy

"INTRODUCTION The fuel requirements for industrial and domestic consumers in New England, in normal times, are supplied almost entirely by fuel oil, anthracite, and bituminous coal. A shortage of these fuels occurred during the war. This shortage was caused by (1) The diversion of oil to military uses; (2) the use of railroad and boat facilities that ordinarily would transport coal for the transportation of war materiel; (3) the inability of coal mines to apply the increased demand for coal which resulted from the conversion from oil to coal by domestic and industrial consumers; and (4) the increased demand of war industries for coal. Because of this critical fuel situation, an investiga¬tion was made of possible sources of fuel nearer to points of consumption in New England. Meta-anthracite, which is a satisfactory fuel for some purposes, had been mined in Massachusetts and Rhode Island many years ago. However, the introduction of freer-burning anthracite and bituminous coal into New England markets resulted in the abandonment of these mines.The coal mined in the vicinity of Portsmouth on Aquidneck Island, Newport County, R. I., had been used successfully for smelting copper ore and for fuel. It is reported that this coal is less graphitic than the material mined at Cranston near Providence, R. I. The coal is meta-anthracite and does not burn freely. However, improved equipment for burning coal has been developed, and if minable reserves of meta-anthracite should be found, methods of burning it probably could be devised.The purpose of this investigation was to determine sources of additional fuel. Since meta-anthracite mined at Portsmouth had been used with some success, an investigation was undertaken to determine the characteristics and continuity of the beds in this area."

Apr 1, 1948

By Irving Hartmann

The Experimental Coal Mine of the Bureau of Mines has served principally as a valuable and unique testing laboratory for studies of the explosibility of coal dust and mine gas; studies of the numerous complex and interrelated chemical and physical factors that govern the ignition of coal dust and the propagation of mine explosions; and studies designed to develop measures for preventing explosions or reducing their destructive effects. These researches, coupled with educational efforts by the Bureau of Mines and enlightened safety consciousness in the mining industry, had fruitful results. This is evidenced by the remarkable reduction in the frequency of major coal-mine explosions and the number of fatalities from explosions since the Bureau of Mines was established. Despite this progress, further important unresolved problems arise; these are due in part to changes in mining conditions and methods, which have brought about increased production of fine coal dust in highly mechanized operations. To solve the new problems, research must be continued without interruption. The results of many very recent and current studies in the Experimental Coal Mine are summarized briefly, and pertinent studies by European mine-safety-research organizations are listed.

Jan 1, 1957

By L. Yuan, A. C. Smith

MFIRE, the mine-fire simulation program of the U.S. National Institute for Occupational Safety and Health (NIOSH), is widely accepted as a standard for assessing and predicting the impact of a fire on the mine ventilation system and the spread of fire contaminants in coal and metal/nonmetal mines. MFIRE has been used by U.S. and international companies to simulate fires for planning and response purposes. It is a dynamic, transient-state, mine ventilation network simulation program that performs normal planning calculations. It can also be used to analyze ventilation networks under thermal and mechanical influence, such as changes in ventilation parameters; external influences, such as changes in temperature; and internal influences, such as a fire. The program output can be used to analyze the effects of these influences on the ventilation system. Since its original development by Michigan Technological University for the former U.S. Bureau of Mines in the 1970s, several updates have been released. In 2012, NIOSH completed a major redesign and restructuring of the program with the release of MFIRE 3.0. MFIRE’s outdated Fortran programming language was replaced with an object-oriented C++ language and packaged into a dynamic-link library. However, the MFIRE 3.0 release included no change or improvement to the fire-modeling algorithms inherited from its previous version, MFIRE 2.20. This paper reports on improvements that have been made to the fire-modeling capabilities of MFIRE 3.0 since its release. These improvements include the addition of the t-squared fire as a new fire-source model and the ability to include available heat-release-rate versus time data, the addition of a moving fire source for conveyor-belt fire simulations, improvement of the fire location algorithm, and the identification and prediction of smoke-rollback phenomena. All of the improvements discussed in this paper will be included in MFIRE 3.1 and released by NIOSH in the near future.

Jun 1, 2016

By Doris Hiam-Gálvez

El presente trabajo describe las últimas tecnologías que mejoran la minería en América Latina y la eficacia en el procesamiento del mineral. Así también se revisa el modo innovador de energía a través de la fundición de sales con energía solar, particularmente en regiones desérticas de América del Sur. Cada tecnología ofrece mejoras sustanciales en eficiencia, capital, y costos operativos y contribuye a la reducción el impactom ambiental de las operaciones mineras.

Feb 1, 2012

By Michael W. Lewis

The latest downturn in the world’s metal prices has forced many mining companies to focus on cost reduction and productivity improvements to remain competitive. Maintenance represents a significant part of the overall operating costs in the mining industry. A structured, proactive maintenance approach, such as reliability-centered maintenance, can achieve cost reductions and productivity improvements. Remote condition-monitoring systems are becoming commonplace because they have the potential to identify problems before failure. Detection of equipment degradation before failure will enable repairs to be scheduled, thereby reducing costs and interruptions to production. The mining industry is in the midst of uncertain times. Decreasing commodity prices, demand, head grade and capital availability along with increasing environmental requirements have put pressure on mining companies to significantly reduce costs to maintain short- and long-term viability. Corporations are looking at expansion, merger/consolidation and financial/hedging programs to achieve these cost reductions. Mines are reducing costs by eliminating all but essential expenditures, increasing production levels, reducing overtime and investing in new technologies.

Jan 1, 2000

By C. J. Hall

This paper presents a basic motive column analysis of natural ventilation and shaft resistance, using the density depth diagram. The method makes use of tables showing the state of the air as determined by thermodynamic analysis. Several theoretical examples are given.

Jan 1, 1968

By W. G. Hatch

Introduction In November, 1927, a paper was presented at the Annual Meeting of the British Columbia Division by H. A. Pearse(l), in which he described the milling practice at Britannia and set forth the metallurgical results which were being obtained at that time. In the intervening four years, various changes and additions have been made in equipment and practice, which have resulted in marked improvements in efficiency and costs. These changes and their effects are discussed in the present paper. During the past few years two major changes have been made in plant equipment. The first of these was the. elimination of an intermediate crushing stage by discarding two gyratory crushers in favour of two Symons cone crushers. The latter installation-now effects in one stage a greater reduction than was formerly accomplished in two, that is, by the gyratories together with a set of rolls. The second important change in equipment took place when the original M.S. flotation machines were replaced by six Forrester pneumatic machines, so that now the flotation department consists entirely of machines of this type. A number of minor changes and some further additions to equipment have also been effective in raising plant capacity and concentrate grade, while making noticeable reductions in tailing losses and costs of ore treatment.

Jan 1, 1932

By Tristan Joubert, Fabio Panella, LiLing Chen, Yung Loo, Michael Devriendt, Nasir Qureshi, Ahmad Ali

Tunnel inspections have traditionally been carried out manually by inspectors writing up observations and taking photos of defects. The results from the inspection and the defects observed are dependent upon the rigor of the inspectors and may be subject to repeatability and consistency issues and is often time consuming with elevated health and safety risks. This paper will discuss work that is being carried out in developing and implementing an innovative hardware and software solution integrating machine learning to automate the process of capturing objective tunnel condition information, offering cost and programme savings as well as health and safety improvements

Jun 13, 2023

By C. J. Wilhelm

Brine produced from subsurface formations may be employed successfully instead of fresh water as a flooding, medium in the secondary recovery of oil. The feasibility of this substitution has been proved in the shallow "shoestring" area of eastern Kansas and northeastern Oklahoma, where the supply of fresh water often is limited. In this procedure all brine produced with the oil is returned to the formation and thus is prevented from contaminating streams and fresh-water supplies. This report includes a detailed description of a "flood project" in eastern Kansas studied by the Bureau of Mines. In an attempt to determine whether brine, when handled properly, can be used as effectively as fresh water in flooding oil from partly depleted, formations, an analysis was made of all .own conditions that influence flooding.

Jan 1, 1941

By William Gleason

The Dulles Corridor Metrorail Project is a $3-billion project that will link Dulles International Airport with the downtown center of Washington D.C. by way of a single seat train ride. The project is mostly above ground, but it does include two short, yet complex, tunnels through the area of Tyson?s Corner. The project is being completed in two phases. The Dulles Transit Partners (DTP), led by Bechtel, was awarded the first phase, a $1.6-bil-lion phase that includes 17 km (11 miles) of track with five stations. At Tyson?s Corner, the project includes twin 730-m- (2,400-ft-) long, 6-m- (20-ft-) diameter tunnels. Bechtel is self-performing construction for the $1.6-billion design-build job. Gall Zeidler Consultants was hired by DTP as designer for the NATM tunnel portion of Phase 1, and Beton-und-Monierbau was hired as tunnel subcontractor. Tyson?s Corner is an affluent and congested area that sits 152 m (500 ft) above sea level. To get through the area, it was decided that tunnels would be the best option with the least amount of disturbance to the surrounding areas. However, with extremely shallow groundcover above some points as well as soft soil throughout, the tunnels are also the most complex aspect of Phase 1. About 213 m (700 ft) was constructed utilizing the cut-and-cover method. The remaining 518 m (1,700 ft) is being constructed using the New Austrian Tunneling Method, which integrates the principles of the behavior of rock and soil masses under load, and monitoring the performance of underground construction during construction. ?The tunnel only falls 2 m (7 ft) from one end to the other and we pass through two soil conditions, they are both soft ground,? said Dominic Cerulli, tunnel task manager for Bechtel. ?Soft ground is very tricky because you have to close the ring in a timely manner to minimize settlements at the surface. If you don?t close the ring quickly to achieve a round structure that?s good in compression, the tunnel could start necking and squatting and the ground above it will settle. We are under major roadways, so excessive settlement would be a bad thing.?

Jan 1, 2011

By Y. Zhang, M. Yekich, C. Zhou, C. Jobes, J. Galanko, D. Tuchman, J. Srednicki, J. Carr

The continuous personal dust monitor (CPDM) is an essential instrument for working in hazardous environments, is used to monitor real-time coal dust exposure, and is mandated by the Mine Safety and Health Administration (MSHA) for underground coal mines. Researchers from the National Institute for Occupational Safety and Health (NIOSH) found that it is possible for electromagnetic interference (EMI) between a CPDM and a proximity detection system (PDS) to occur. Various approaches have been taken by researchers and manufacturers to address this EMI issue. Administrative controls were recommended to keep the CPDM six inches away from the wearable PDS device. Shielding pouches were made to contain the electromagnetic (EM) emission from the CPDM. Metal shielding was added to major EM emitting components. EMI filtering with large capacitors was introduced to mitigate EMI. Most recently, a novel magnetic-field-cancellation-based approach was developed and achieved remarkable results. In this paper, we provide a comparison between these approaches. The pros and cons of each approach are presented and discussed, so that mining device manufacturers and operators can best evaluate the technology and controls that improve the health and safety of mine workers.

Feb 1, 2023

By R. Barany

The heats of formation of seven substances were determined by solution calorimetry. At 298.15° K, the heat of formation of lithium sulfate from lithium, rhombic sulfur, and oxygen was -343.1 ± 0.7 kcal/mole, and the heat of formation of lithium sulfate monohydrate from lithium, rhombic sulfur, oxy-gen, and hydrogen was -414.3 ± 0.7 kcal/mo1e. For the silicates, the heats of formation at 298.15° K from the elements were kaliophilite, -503.8 ± 0.5 kcal/mole; leucite, -721.6 ± 0,8 kcal/mole; eucryptite, -505,2 ± 0.6 kcal/mole; alpha-spodumene, -727.9 ± 0.9 kcal/mole; and beta-spodumene, -721.1 ± 0.9 kcal/mole. The corresponding heats of formation at 298.15° K from the constituent oxides were kaliophilite, -42.7 ± 1.1 kca1/mole; leucite, -42.8 ± 1.1 kcal/mole; eucryptite, -16.1 ± 0.7 kcal/mole; alpha-spodumene, -21.0 ± 0.7 kcal/mo1e; and beta-spodumene, -14.3 ± 0.7 kcal/mo1e.

Jan 1, 1966

By John H. Schilling

The Gabbs magnesite-brucite deposit is unique in size and is one of two magnesite deposits being exploited in the United States. It is near the town of Gabbs, which is one hundred miles southeast of Reno, in west-central Nevada. The brucite was discovered in 1927; the magnesite was found while exploring the brucite. During World War II, more than 80,000 tons of magnesium metal was produced from about 900,000 tons of magnesite ore mined from these deposits. An additional 5,000,000 tons of magnesite and 1,000,000 tons of brucite have been produced for use in making magnesia refractories and chemicals. Basic Inc., presently the only producer, mines 1.5 ± 0.25 million tons of ore and waste annually using high-selective open-pit rriethods; the ore is up-graded, calcined, and processed into a variety of products. Known reserves of highgrade (less than 5 per cent CaO) magnesite ore total more than 25,000,000 tons, and there are larger tonnages of lower-grade material; brucite reserves are small. The magnesite and brucite are in generally west-dipping dolomite of the upper member of the late Triassic Luning Formation, in the over-riding plate of the Paradise thrust fault. A great variety of dikes and a stock of Cretaceous granodiorite intrude the Luning Formation in the vicinity of the magnesite-brucite deposit. The magnesite bodies are scattered over an area of about a square mile around a prong of granodiorite which extends north from the stock. The brucite is mainly in two bodies in contact with the prong of granodiorite; at the surface and along deeper cracks the brucite has weathered to hydromagnesite and artinite. In the area of magnesite-brucite mineralization, much of the dark, fine-grained, schistose, regionally-metamorphosed dolomite of the Luning Formation has been marmorized to a lighter-colored, coarser-grained, massive dolomite that is intergrown in varying proportions with the magnesite. The magnesite and marmorized dolomite can not be distinguished visually. In addition to the two varieties of dolomite, the gangue in the magnesite and brucite bodies mainly is the various varieties of dike rock, serpentine and a variety of other "contact" minerals, and "post-ore" dolomite and calcite. The magnesite ( and recrystallized dolomite) is believed to have formed by the hydrothermal replacement of the regionally metamorphosed sedimentary dolomite; alternatively it has been suggested that the magnesite is sedimentarv and formed contemporaneously with the dolomite in an embayment of the Triassic sea. Because all the igneous rocks exposed in the immediate vicinity of the magnesite deposits appear to be younger than the magnesite, the ore-forming solutions are thought to be related to a somewhat older granite which crops out elsewhere in the area. The brucite is the result of contact-metasomatic replacement of magnesite during the emplacement of the granodiorite stock.

Jan 1, 1968

By Lewis C. Karrick

This paper is based on data obtained in the course of the oil - shale investigations of the U. S. Bureau of Mines , conducted in cooperation with the State of Utah . The amount and quality of oil that can be produced from any shale may be made to vary to an important degree by changing the temperature relations existing in the shale charge during destructive distillation . The rate at which the oil is formed from the shale is affected by the rate of heat supply , and therefore by the temperature of the shale during its thermal de composition . The quality of the oil formed may be controlled by altering the temperature of the shale , and therefore , the rate of formation of the oil . Variations in the yield and quality of shale oils may be caused by inherent properties of the retort used , but in any event the properties of the crude oil and yield are very largely the result of the extent to which the thermal de composition has progressed . Recognition of these principles will aid in explaining to a large degree the reasons for the wide variations in oils produced from the same shales by different " processes " . These principles also may be applied in the operation of different types of retorts in order that crude oils of a type most profitable to the operator may be produced . The Bureau of Mines has conducted an extended series of tests in the dee structive distillation of oil shales , in order to determine the wide variations that may be effected in the quality and yield of shale oil by changing the rate and temperature at which the oil is formed . These tests furnished interesting information on the four related points : yield of oil , quality of oil , temperatures required to distill shales , and time required for distillation .

Mar 1, 1923

By James Westfield

A brief résumé follows of activities of the Division of Coal-Mine Inspection that have had a favorable effect on health, safety, and the reduction of injuries at coal mines: 1. The Federal Mine Safety Code fur Bituminous Coal and Lignite Mines of the United States was issued originally by the Director of the Bureau of Mines on July 24, 1946, after consulting with management and labor representatives of the coal-mining industry. The code has been used by Federal coal-mine inspectors while inspecting bituminous-coal and lignite mines as a basis for determining the existence of unhealthful and unsafe conditions and practices in these mines. A revised code was issued by the Secretary of the Interior on October 8, 1953, after further consultations with representatives of management and mine workers and was incorporated by reference in the 1952 and subsequent bituminous -coal wage agreements. The agreement of May 29, 1946, between the Secretary of the Interior, acting as Coal Mines Administrator under authority of Executive Order 9728, and the United Mine Workers of America, covering bituminous-coal and lignite mines in Government possession, charged Federal coal-mine inspectors with the responsibility of making periodic investigations of the mines and reportin; to the Coal Mines Administrator any violations of the Federal Minis Safety Code. Federal coal-mine inspectors also had temporary authority to close mines found to be imminently dangerous, but such authority under Executive Order 9728 was removed on June 30, 1947, when Government control of the mines was terminated.

Jan 1, 1960

By Jankola W. A, Delong O. J

Historically, the silica content of zinc concentrates treated at Cominco's Trail Operations has been low. Silica in the roaster calcine seldom exceeded 1.5 per cent because of the low silica content of concentrate from Cominco's Pine Point mine. With the shutdown of Pine Point, alternate sources of concentrate were required and it was anticipated that calcines containing greater than two per cent silica (with excursions above three per cent) would have to be treated. Previous experience indicated that the existing leaching circuit could not tolerate such high levels. Therefore, a research program was undertaken to identify the key factors affecting silica precipitation; to compare different process alternatives; and to make recommendations for modifications to the existing plant. A project to modify and upgrade the leaching circuit has now been completed. Calcines with higher silica contents are successfully treated, but the upper limit of the circuit is unknown. The results of the research work will be discussed and the new leaching plant will be described. Recent operating results will also be presented.

Jan 1, 1993