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By Richard G. Almes

Since the failure of a major coal refuse disposal embankment and impoundment in the Buffalo Creek watershed near Man, West Virginia in early 1972, there have been extensive changes in the design and construction requirements for coal refuse disposal facilities located throughout the United States. The primary emphasis has been on improving the safety of these facilities, particularly for impoundments which are capable of storing millions of gallons of process water and storm runoff. The Mine Safety and Health Administration (MSHA) of the U.S. Department of Labor (formerly the Mining Enforcement and Safety Administration, U.S. Department of interior) has been the lead federal agency in promulgating regulations pertaining to coal waste disposal. In 1974 and 1975, studies were undertaken by our firm under contract to the Mining Enforcement and Safety Administration to prepare a comprehensive engineering and design manual to be used by operators and engineers in the planning and design of coal refuse disposal facilities with the intent ion of avoiding any more Buffalo Creek failures. The resultant 800-page document addresses major subjects such as safety, environmental controls, and cost. Specific topics include characterization of coal refuse, classification of disposal facilities, project planning, geotechnical investigations, testing and design requirements, hydraulic and hydrologic design, environmental factors, operations, and monitoring, instrumentation, and maintenance.

Jan 1, 1980

By V. G. Lofftus

Since plant start-up in January 1983, Golden Sunlight Mines, Inc. has implemented several process changes and improvements. Among these are a pulp preaeration circuit and a sand tailings retreatment circuit. The purpose of the preaeration circuit is to reduce reagent consumption during gold dissolution. The sand tailings retreatment circuit was added to recover and process separately pyrite concentrate to maintain acceptable overall gold recoveries with the more refractory sulfide ores. Research and plant operating data along with process and improvement descriptions are presented.

Jan 1, 1987

By Langtry E. Lynd

The titanium dioxide pigment industry in the United States has always relied to varying degrees on imported titanium concentrates. Dependence on foreign ilmenite was especially high (generally over 85% of consumption) until 1942, when large-scale U.S. production of ilmenite began, and has since ranged from 12% to 47%. Rutile import reliance was generally in the 45% to 80% range until the early 1960's, when increased use in the chloride pigment process raised dependence on imported rutile to over 90% in most years since 1963. Import reliance of zircon, obtained almost entirely as a byproduct of titanium mineral production, has generally ranged from about 30% to 65% of consumption. This paper will examine the history of U.S. sources of these heavy mineral commodities, and will discuss the potential U.S. future supply in view of changing industrial uses and processes and the anticipated development of new heavy-mineral-sand processing operations, such as those at Richards Bay in the Republic of South Africa and in Sierra Leone.

Jan 1, 1978

By Liming Yuan, Isaac Zlochower, RICHARD THOMAS, Thomas H. Dubaniewicz, Teresa Barone

Mining vehicle manufacturers are developing lithium-ion (Li-ion) battery electric vehicles as an alternative to diesel-powered vehicles. In gassy underground mines, explosion-proof (XP) enclosures are commonly used to enclose electrical ignition sources to prevent propagation of an internal methane (CH4) air explosion to a surrounding explosive atmosphere. Li-ion batteries can create pressurized explosions within sealed enclosures due to thermal runaway (TR). Researchers at the National Institute for Occupational Safety and Health (NIOSH) measured TR pressures of lithiumiron phosphate (LFP) cells as a function of free space within sealed enclosures and observed an inverse power relationship. A well-confined cell produced 294 bar (4260 psia) of pressure during a TR, far exceeding minimum pressure containment specifications for conventional XP enclosures. Results indicate that adding enough free space surrounding LFP cells can reduce TR pressures to levels below that expected for CH4-air ignitions. Measured TR temperatures were below the minimum autoignition temperature of CH4-air.

Nov 6, 2020

By N. B. Aughenbaugh

Subsidence due to abandoned coal mines has received copious attention recently. This is a result of many factors such as the enactment of new mining laws and the effect subsidence has on land use over the mines. Prediction of subsidence features and the time aspects over supercritical extraction (i.e., longwall and high extraction ratio pillaring) is relatively accurate. However, predicting when subsidence will occur and the surface features' size and shape above subcritical extraction of room and pillar mining is not yet possible. This paper will discuss the factors that influence the time aspects of subsidence in room and pillar mining.

Jan 1, 1983

By George Fumich

The Office of Coal Research has been supporting the development of processes for producing synthetic pipeline gas from coal since 1964. .Some of this work has also been jointly supported by the American Gas Association. The work has progressed through laboratory investigation, to bench scale, to pilot plant. It was far from a crash program, generally being fund-limited.. As of one year ago, we had reached the following position: 1. The Institute of Gas Technology HYGAS. process pilot plant in Chicago, Illinois, was in the process of being finally completed. This plant is designed to produce about 1,500,000 cubic feet of pipeline-quality gas per day from 75 tons of coal. 2. The Consolidation Coal Company, CO2 Acceptor Process pilot plant in Rapid City, South Dakota, was well._ on its way to completion. This plant, designed primarily for lignite and subbituminous coals, has about one-half the design capacity of the HYGAS plant. Additionally, the initial construction did not provide for cleanup and methanation; only the preliminary synthesis gas is produced. 3. The Bituminous Coal Research, Inca, BI-GAS pilot plant was in a preliminary design stage. A site had been selected near Homer City, Pennsylvania, to build this plant, planned to consume 120 tons of coal per day. Meanwhile, as you are all well aware, a natural gas shortage was developing in this country. Much has been published about it, so I will not. bother you with further details. Suffice it to say that the reserve-to-production ratio has been steadily declining, because we have been using.-as-faster than we have been find-

Jan 1, 1972

By Cleophus Short

[Of the many occupations in and about the coal mines, those of the haulage crews are among the most hazardous. Statistics ship that the second greatest number of fatalities about the coal mines occur during haulage ion and through the use or misuse of haulage equipment. During the five year period between January 1, 1957 and January 1, 1962, the m stone mine had a. Sack haulage frequency of 4098 and mined 3, 541,939 toads per haulage fatality. Coal mire haulage is similar in respects to railroading. We gee very serious consideration to the instillation of tack and to the selection of the haulage crews. In doing this, we are attempting to have our coal mine haulage as. Safe as that of the railroads.]

Jan 1, 1963

By Howard E. Kremers

Although more than 100 thorium-rare earth minerals are known, only a few have any commercial significance. Monazite, thorite, bastnasite, and some exotic thorium rare earth ores are reviewed Commercial interest is presently centered on monazite from the Union of South Africa, and thorite from this country. Thorium became commercially important with the development of the incandescent gas mantle about 75 years ago, Gas mantles consist of thorium oxide with small amounts of cerium oxide. The thorium nitrate used to make gas mantles was first obtained from rare thorium minerals, As a matter of fact, this use of thorium is still important and is one of the largest commercial uses for thorium materials. The discovery of monazite sand placer deposits along the coasts of Travancore, India, and in some Brazilian beach s .s, and the development of the old North and South Carolina monazite stream placers gave the mantle industry of 30 to 40 years ago a comfortable inventory of thorium ore. Even today, the thorium industry depends largely upon monazite ores for its source of thorium. This paper will briefly describe some of the major thorium ores and their principal deposits insofar as they relate to the thorium industry in this country. Because of similar chemical and physical properties, thorium always occurs with the rare earth elements and with varying amounts of yttrium. Thorium may predominate over rare earths, as in thorite-type minerals, or may represent only a fraction of the rare earth content. Typical ratios of thorium to rare earths in various minerals are given in Table 1, The average thorium content of the earth's crust is about 12 grams per ton, and in this respect thorium approximates lead, molybdenum, and some of the rare earths in abundance. The ore minerals of greatest importance to the-thorium-rare earth industry are monazite, thorite-type minerals, bastnasite-type- ores, and the family of minerals which is characterized by a preponderance of the heavy rare earths and yttrium. The latter classification includes xenotime, gadolinite, samarskite, euxenite, etc, The first two, monazite and thorite, are of greatest significance.

Jan 1, 1958

By Juan L. Yarmuch, Gonzalo Sepulveda

This article presents a novel approach to address the mining width-constrained open pit mine production scheduling problem in the context of medium-term planning. A mathematical formulation is proposed to incorporate mining width constraints into the production scheduling process, aiming to maximize the NPV of the schedule while ensuring enough room for the operation of mining equipment. To tackle the computational challenges posed by large-scale instances of the problem, we propose a method based on variable fixing and horizontal precedence generation. In this study, we apply the developed model to real-world scenarios from Radomiro Tomic short-term mine planning problems such as optimizing the timing of major truck maintenance and the impact of external factors, like the delay in the production of the Chuquicamata underground project. Remarkable improvements are observed with the mining width-constrained model. Specifically, the mining width satisfiability is enhanced from 2 to 60% compared to the traditional open pit mine production scheduling model, underscoring the significance of incorporating these constraints. The proposed method showed good results reaching optimality gaps within 5%.

Mar 28, 2024

By L. H. E. Weyher

In a previous paper presented at the 1966 Annual Meeting of AIME we reported our work, conducted at the Pennsylvania State University, on the hydrocyclone washing of fine coal.' The initial evaluation based on that work demonstrated the feasibility of hydrocyclones as fine-coal cleaning devices, and in that previous paper we presented selected test data that showed in principle how product yield and assay respond to variations of the major cyclone operating variables. The present paper reports in greater detail on the findings and presents a comprehensive evaluation of our data as follows: ? Hydrocyclone throughput rates were related to feed pressure and other variables by regression equations. These equations are compared with other capacity- versus-pressure drop expressions taken from the literature on classification cyclones.

Jan 1, 1968

By Y. Ye

Typically, rougher molybdenite flotation and recovery from bulk copper/ molybdenum concentrates involves the use of alkalisulfides, Nokes reagents, cyanides, oxidants, and/or thermal treatment for the depression of copper sulfide minerals. The bulk copper/molybdenum feed generally varies from 0.2% Mo to 1.0% Mo, and with traditional reagents the single-stage rougher flotation recovery of molybdenite varies between 40 and 90% at a concentrate grade of 5 to 10% Mo. With ozone conditioning for copper depression, however, improved separations appear to be possible, as demonstrated by tests with Cu/Me concentrates from both the Phelps Dodge Morenci Operations and the Kennecott Copperton Operations. Single-stage rougher flotation after ozone conditioning can provide a molybdenum concentrate at a recovery of more than 90% and a rougher concentrate grade higher than 20% Mo in some cases. Subsequent cleaner flotation with additional ozone conditioning results in relatively copper-free molybdenum concentrates containing as much as 52% Mo. Preliminary analysis indicates that, with a multistage ozone conditioning/flotation strategy, the process is technically and economically viable and should be suitable for industrial application.

Jan 1, 1990

By John W. Barnes

In seeking cost reductions, control methods are a fertile field because they significantly affect labor and other costs. While process control in uranium mills is excellent by the evidence of high recovery, the costs seem high to those familiar with extractive operations for other metals. To some extent this high cost is inevitable, because of exacting quality control-, the technically complicated recovery processes; poor control over grade and nature of mill feed- special problems arising out of the radioactive property of the material. Practices used in uranium mills and the limitations indicated for instrumentation and automation are discussed. It is concluded that any large investment in automatic controls should be preceded by a careful study of their reliability and maintainability, and an estimate of the net income after taxes smaller plants my find it more profitable, or at least less risky, to concentrate their efforts on the possible reduction of some control problems and to development of a stable force of skilled employees. The observed experience does not inspire optimism that ore-dressing plants can be extensively automated although certain unit operations offer a challenge for improvements in instrumentation and machine design.

Jan 1, 1960

By J. DuCarme, A. Smith, M. Reyes

"A magnetic proximity detection system is mounted on a mobile mining machine to prevent underground workers from being pinned or struck by machine motion. The system generates magnetic fields around the machine to determine safe working distances. The minerworn component measures the magnetic field in order to approximate location. Large masses of steel, such as those from mining equipment, can alter the magnetic field distribution. This affects the locational accuracy of the system, thus adversely impacting worker safety. To examine this problem, U.S. National Institute for Occupational Safety and Health researchers developed a method and test system to study the influence of a steel mass on the magnetic field distribution. The results show that a steel plate can strengthen the magnetic field perpendicular to the generator by up to 40 percent. Furthermore, they show that the degree of the influence on the field distribution is a function of distance. The results from this study can be used to further develop and improve the performance and reliability of electromagnetic proximity detection systems used in underground mining applications.IntroductionOn average, 250 miners are injured every year, and 43 miners were reported to be killed by striking or pinning accidents involving continuous mining machines in the United States between 1984 and 2015, according to the U.S. Mine Safety and Health Administration (MSHA, 2015). Continuous mining machines are large mobile machines used to mechanically cut coal in underground mines. These machines weigh approximately 60 t (132,000 lb) each. Although modern continuous mining machines can be remotely controlled, operators still need to be close to the machine primarily because of the low visibility and wide blind spots of the underground working environment.The MSHA promulgated a final regulation in 2015 that requires the use of proximity detection systems on all continuous mining machines except fullface machines. MSHA has approved five such systems to be intrinsically safe for use in underground coal mines: (1) Strata Worldwide’s HazardAvert System, (2) Frederick Mining’s Model 200 HazardAvert Detection System, (3) Nautilus International’s Coal-Buddy System, (4) Matrix Design Group’s M3- 1000/Joy Global SmartZone Gen 1 and (5) Matrix Design Group’s IntelliZone/ Joy Global SmartZone Gen 2."

Jan 6, 2018

By L. H. Michaud

An existing mining company plans to extend their surface coal mining operations in central Pennsylvania. Although the proposed site contains pyritic material, the results of the acid-base accounting for the site show an overall NP:MPA ratio of 4.26:1 for the entire site. The pyritic material is, however, associated with the lower of the three seams to? be mined. If traditional dragline mining methods were used, this would result in the acidic material being placed at the top of the spoil piles, exposing it to air and water, and therefore to the formation of Acid Mine Drainage (AMD). Further concerns are associated with the fact that the alkaline material is not distributed evenly over the mine site. In order to prevent the formation of AMD, the company has proposed to mine the area using Truck/Shovel mining methods. This technique offers a more flexible alternative for cut sequencing and for the selective placement of waste material. Working with the Department of Mineral Engineering at The Pennsylvania State University, a mine plan was developed for this site. This plan results in the layering of the alkaline and acidic spoil in order to achieve an overall net alkalinity in all spoil areas. Mining of this site should therefore not result in the formation of AMD.

Jan 1, 1994

By E. G. Cauda

Diesel engines are a major source of underground miners? exposure to nitrogen dioxide. In an effort to reduce the exposure of underground miners to regulated and unregulated diesel emissions, primarily particulate matter, mining companies in the U.S. are retrofitting existing and introducing new engines with various exhaust aftertreatment technologies. Different aftertreatment devices, or changing the operating temperature of a selected device, can have unexpected effects on the concentration of nitrogen dioxide emitted by a diesel-powered piece of equipment. This paper provides an overview of the effects different exhaust aftertreatment technologies available to the mining industry have on no2 emissions.

Jan 1, 2010

By Roberto L. Romero

The dressing of Bolivian tin ores has been done up to the present by classical. gravity methods, taking advantage of the high specific gravity of cassiterite compared with that of the accompanying gangue. For this purpose, jigs and shaking tables are used in the treatment of the various size fractions in which the ore is classified. Bolivian ores are mainly of the vein type and, to obtain a reasonable separation, crushing and several stages of grinding are necessary during the process to substantially liberate the cassiterite from the gangue. Gravity processes for cassiterite are effective for sizes down to 200 mesh. Below this size the efficiency of the gravity methods falls off very rapidly with increasing fineness of the mineral grains. The conventional treatment for this material is desliming followed by tabling on shaking tables various other types of machines have been designed for the gravity treatment of these fine particles but they have had limited success. Bolivian ores contain an appreciable amount of minus 200 mesh material constituted by "primary fines" caning from the mine itself, and "secondary fines" originated during the crushing and grinding necessary for liberation of the difficulty in the treatment of these fine particles is one of the causes why the recovery of tin in concentrates is only of around 50% in the mines owned by Corporacidn Minera de Bolivia, the State owned enterprise. The average figure for other Bolivian mines is

Jan 1, 1971

By W. Gibson Jaworek

Of increasing importance to the student of fuels economics has been the extent to which different primary energy sources can substitute for each other in the various energy markets of the nation. Knowledge of the nature and extent of fuel interchangeability can aid the fuels economist in projecting trends of energy utilization, as well as giving him a better understanding of the past and present conditions of fuel markets. It is also important to the consumer to know just how much flexibility he can maintain in his energy consuming operations. And, finally, various governmental bodies show keen interest in the degree of energy substitutability in determining public policies concerning the fuels industries. The presence of excess fuel production capacity in the United States during the early 1960's indicates that fuel interchangeability should become more prevalent in the increasingly competitive energy markets of the nation. Discussion of fuel intercompetition is almost always restricted to qualitative terms-because of the lack of comparable statistical data, between the different energy sources in geographic or "type-of-use" fuel, markets. There are exceptions, of course, such as, the excellent fuel consumption data which are available on steam electric generating plants throughout the nation. In other sectors, statistics are at best incomplete.' Inmost instances, indirect fuel consumption indicators, such as sales of fuel burning equipment, are extensively used to measure market shares of a particular fuel; however, these indicators are hard to evaluate precisely without prior knowledge of the total competitive market.

Jan 1, 1961

By Fred Pena

The VERTIMILL has proven itself to be a reliable performer in heavy duty industrial applications. Applications have been extensively used in the mining industry, flue gas desulfurization applications, and industrial minerals field. The machine is a vertically stirred machine that utilizes a screw operating in a grinding media. Grinding media types have ranged from several sizes of steel balls as the most common to pebbles or ceramic media. Mesh-of-grind and final product size are the determining criterion for the selection of the media size used. Product size consists have ranged from very coarse to super-fine grinds of less than 25 microns. Savings in consumption of power, grinding media, and liners when compared to a conventional ball mills, have been realized. Savings in consumption of reagents have also been demonstrated.

Jan 1, 1992

By Feng Liu

"With seven new applications for plans of work for exploration in the international Seabed Area approved by the Council during its twentieth session of the International Seabed Authority, 26 total approvals have been made by the Council up to date. Among them, three contracts were made with COMRA. On 8 August 2014, China Minmetals Corporation submitted another application to the Authority for approval of a plan of work for exploration for polymetallic nodules in the Area, which is also sponsored by the Government of the People’s Republic of China.China is one of the main contributors to the international seabed regime. The Presentation will describe China’s activities in the Area, such as exploration, technology development, environmental protection and policy making.JIAOLONG is a submersible with capacity of 7000 meters. JIAOLONG’s sea trials were carefully made in 4 years, from 2009 through 2012 and it successfully dove to a depth of 7062m in June 2012 at Mariana trench. A so called "Test Application Phase" started thereafter, and is planned to last for 3-4 years. Two cruises and 4 legs have already been made since then. A wide-range of findings were obtained during dives in South China Sea, and in COMRA’s Exploration Contract Areas for polymetallic nodules and cobalt-rich ferromanganese crusts. This presentation will reveal the colorful findings."

Sep 1, 2014

The mining industry is an important economical factor in Vietnam. Mining is presently being conducted at about 60 locations and at over 1000 mines. Petroleum extraction and coal mining are the most important parts of industry though metals such as zinc, tin, chromites, iron are also extracted. Last year the sector produced 20 million tons of crude oil, 26 million tons of coal and 500,000 tons of apatite. In particular, Vietnam is one of the world?s largest producers of anthracite, and it is one of the top producers of ilmenite and zircon in the Asia-Pacific region. The government intends to increase the mining production on all levels, however, at present one can observe adverse impacts of the mining activities on the natural environment such as insufficient waste dump rehabilitation, occurrence of acid mine drainage, mining subsidence and emissions as well as lack of appropriate water treatment facilities. This paper describes the current mining situation, future perspectives, the major environmental challenges of the country and approaches to solve these problems. Particular emphasis will be given to the research project ?RAME ? Research Association on Mining and Environment in Vietnam?, a venture carried out by universities, research centres and industry. This project is worked out in collaboration with the national Vietnamese coal and industrial minerals company VINACOMIN.

Jan 1, 2006