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By George M. Potter

Under contractural arrangements with the Bureau of Mines, Mountain States Research and Development, Inc. (MSRD) completed a technological investigation to determine the feasibility of in situ mining of metal commodities other than copper and uranium, The study was based upon available literature and experience. The selection of potential candidates for in situ mining was influenced by economic importance, probable amenability to in situ methods, and environmental considerations. Four metals (or metal pairs) were chosen for feasibility studies: aluminum (with a copper byproduct), gold-silver, and manganese were recommended for further study and action; cobalt-nickel was also recommended contingent upon preliminary laboratory leaching and recovery investigations and field geohydrological work. Mining and recovery plans and an economic evaluation are included. Other metals with potential for in situ leaching are lead/ zinc, molybdenum, and vanadium.

Jan 1, 1981

By Floyd C. Bossard

In underground mining operations, the over- riding issue has to be protection of worker health and safety. The employees underground, making a living in a dangerous occupation, know these are major issues. These men bargain their lives and health on the presumption that the operating management knows its business, and they, the underground employees, can pursue their occupation with the assurance that management has provided a safe and healthy ambient underground environment. When management assumes the mantle of protection of underground workers, it has to be positive that qualified engineers have designed the project, and that capable operating personnel are in charge and always available. Those persons with these responsibilities must be knowledgeable in the engineering and occupational health aspects of sine ventilation. The ultimate function of a mine ventilation system is to provide a comfortable, healthy and safe ambient environment for the underground workers. The attainment of these objectives has been complicated with the increased application of electrical equipment and diesel-powered mechanized mining equipment underground (discharging toxic diesel emissions); increased production rates with the attendant increased production of airborne dust; and mine development in increasingly hostile mineral formations containing combustible strata gases, radon gas emissions, along with high heat and humidity. In general, the modern mechanization of present mining operations has resulted in a sore complex set of problems for the engineer planning the underground ambient environment.

Jan 1, 1983

By Knut H. Hubert

The GRATE-KILN System plant at Svappavaara, Sweden, was constructed for LKAB by Allis-Chalmers under a turnkey contract and commissioned in 1969. The plant was designed to produce iron ore pellets from magnetite concentrate at 6100 mtpd using imported fuel oil. It represented the state of the art for plants of its type at the time. Fuel rated capacity was attained within one week of start-up. Product quality, power usage, fuel consumption and machine wear were within warranty limits during sustained production thereafter. As operator skills improved and gas handling system reserve capability was utilized, the plant frequently produced acceptable product at up to 115% of design capacity. During the period 1969 to 1976, market demands increased for high-quality pellets while energy costs rose steadily. At the same time, important advances in the design of GRATE-KILN Systems were being made in other plants constructed by Allis-Chalmers.

Jan 1, 1980

By Kiran B. Chaudhuri

The Kivcet process is technologically the most advanced of the new lead smelting processes which have been developed over the past decade construction of the first commercial scale Kivcet lead smelter which has been designed by KHD Humboldt Wedag for Sociedad Complejo Metalurgico de Karachipampa is at present nearing completion in Bolivia. Some of the measures taken to minimise emission of harmful elements as well as methods employed to minimise energy consumption in the design of the smelter, are presented. Results of recent testwork which have added to the flexibility of the process are summarised.

Jan 1, 1982

By R. Sellaro, E. Sarver

It has long been understood that extended occupational exposures to respirable mine dusts can lead to chronic lung disease. In underground coal mines, coal workers pneumoconiosis (CWP) and silicosis are major concerns. While many efforts have been made with the aim of understanding the mass-based concentrations and silica contents of respirable dusts under a variety of mining conditions, little research has been completed in characterizing dust at the individual particle level (by composition, size and shape). This study employed scanning electron microscopy with energy dispersive x-ray (SEM-EDX) to analyze dust samples collected from an underground coal mine in Central Appalachia. The results indicated that particle characteristics can vary widely between locations, though many trends might be explained based on knowledge of mining conditions. A continuous personal dust monitor (CPDM) was also used during the collection of some samples to determine respirable dust concentrations, which were compared against estimated concentrations based on the particle-level analysis.

Jan 1, 2014

By David L. Kuck

Siderophyle platinum-group metals and sane gold are a thousand times more abundant in metal and chondritic meteorites than in terrestrial or lunar rocks. Type I and II carbonaceous chondrites contain granules of the high boiling point metals W, Re, Mo, Ir and Os. Metal meteorites and the metal fractions of other chondrites contain siderophyle Pt, Pd, Ru, Rh, Os, Ir and Au. Spectra of sunlight reflected from asteroids, when compared with those of meteorites and specific minerals, provide a rough classification and guide to sources of precious platin-group metals.

Jan 1, 1982

By Arif Emre Dursun, Ali Aras, Hakan Özşen

Specific energy (SE) is defined as the amount of work required to cut a unit volume of rock and is used to estimate the performance of excavation machines. Generally, the SE value is produced from full-scale or small-scale rock cutting tests. However, these tests require expensive equipment and experienced personnel, and the testing procedure is time consuming and impractical. Therefore, for estimation of SE, this study aimed to find a solution to estimate SE using rock mechanics test results and Bond work index values (BWi), which can be produced in a more practical, less time-consuming manner and with inexpensive test equipment. Small-scale rock cutting, rock mechanics and Bond work index tests were carried out on seven rock samples, which can be grouped into two different type of rocks: marble and travertine. In addition, the instantaneous cutting rates (ICR) of a selected roadheader were calculated using SE values. Rock mechanics tests performed in this study were uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), ultrasonic velocity (Vp), Schmidt rebound hardness (RL), corrected point load index (Is(50)) and density (ρ). The simple regression method was used to estimate SE from rock properties and BWi. As a result of this simple regression, a significant and highest correlation was found between SE vs. UCS and Is(50). A good correlation was found between SE vs. BTS, RL and BWi values. A moderate correlation was found between SE vs. Vp and ρ.

Jul 28, 2021

By Fred Pena

Cyprus Pima Mining Company is located in the Mineral Hill District of southern Arizona, approximately 22 miles south-southeast of Tucson. Cyprus Pima Mining Company is owned 50.01% by Cyprus Mines Corporation, 24.99% by Utah International Incorporated, and 25% by Union Oil Company of California, with Cyprus having the management responsibility. Cyprus Pima's history has been one of continued expansion from an initial plant of 3,000 TPD in 1957; 6,000 TPD in 1963; 18,000 TPD in 1966; 36,000 TPD in 1967; and 53,500 TPD in 1972. The major reason for Expansion IV was that a large volume of low-grade ore had to be moved to get at a higher grade ore in the course of proper pit development. With mining costs already defrayed, this relatively hard, low-grade material became economically profitable for subsequent milling and concentrating treatment. Similar material previously stockpiled was available for ore treatment. In an effort to meet the continuing search for lower unit costs, the largest milling and concentrating equipment had to be examined. The management of Cyprus Pima Mining Company began investigating autogenous, and semi-autogenous milling in 1964 when two carloads of ore selected from the Cyprus Pima pit were sent to the Koppers--Hardinge Operation at York, Pennsylvania for testing. One car contained approximately 40 tons of hard arkosite and the other contained approximately 40 tons of ore classified as soft Hornfels. The purpose of the testing was to determine the amenability of both ore types to autogenous or semi-autogenous grinding.

Jan 1, 1974

By B. A. Slaker, T. Miller

"An underground limestone mine in eastern Ohio was experiencing significant floor heave and roof falls, attributed to high horizontal stresses. Areas of the mine showing floor heave were monitored with roof-to-floor extensometers and photogrammetry surveys, to determine the rate and magnitude of heave. Extensometer data were recorded hourly at four locations across adjacent entries while photogrammetry surveys of the floor were performed at the same locations every two to five weeks. A final survey was performed using an I-Site 8200 laser scanner. Following instrumentation, floor heave up to 10.1 cm (4 in) was measured by the extensometers, photogrammetric reconstructions, and laser scanner over a 6-month period. The extensometers were biased by the location where they were placed, failing to consistently capture the location and extent of floor heave and cracking. The photogrammetry surveys were not precise enough to capture small magnitude movements. Mining in the area was halted and within several months the floor movement and incidence of roof falls was significantly lessened. INTRODUCTION Limestone formations in the United States can be subject to relatively high horizontal stresses due to the presence of tectonic loading of the strata. Horizontal stresses have a documented history of causing stability issues in underground limestone mines. Kuhnhein and Ramer (2004) discussed the influence of horizontal stress on complex ground control interactions associated with limestone pillar design and mine layouts. Esterhuizen et al. (2008) documented roof damage observations associated with high horizontal stresses such has roof guttering, beam instability, oval-shaped falls, and failure propagations. There have also been a number of documented case histories of horizontal stress causing unexpected roof and pillar failures at shallow depths (Stacey and Yathavan, 2003). To the knowledge of the authors, there has only been one well-documented case of floor failure causing stability issues in an underground limestone mine. Murphy et al. (2015) documented the role that a weak, moisture-sensitive floor had in the development of a massive roof collapse. For this paper, the study site neighbored, and was in the same general geology of, the site in Murphy et al. (2015). However, the weak, moisture-sensitive floor was not present for the current study. The current study site has experienced significant floor instabilities caused by high horizontal stresses. The instability area was monitored using two different methods to determine if the floor failure would eventually propagate into roof or pillar failure. The objective of this paper is to analyze displacement monitoring measurements from string potentiometers and remote sensing techniques in an area experiencing active movement. Based on the measurement trends and observed damage from inside of the mine, the presumed failure process will be discussed."

Jan 1, 2017

By Robert B. Scott

Acid mine drainage, discharging from coal beds, has polluted our streams and rivers since early time. These pollutants affect water quality by lowering the pH, reducing natural alkalinity, increasing total hardness, and adding undesirable amounts of iron, manganese, aluminum and sulfates, The tangible damages are the costs involved in replacing equipment corroded by the acid water, additional treatment costs at municipal and industrial water treatment plants, and damages resulting from corrosion of steel culverts, bridge piers, locks, boat hulls, steel barges, pumps, and condensers. Intangible damages, which are real and important, include destruction of biological life of the stream, reduced property values, and streams rendered undesirable for recreational uses.1 The major problems of mine drainage occur in the anthracite and bituminous coal regions in Appalachia. However, many of the western mining states have significant mine drainage problems in specific areas, but the overall problem is not as great as in the eastern states.

Jan 1, 1970

By Dale W. Norris

United States Steel's Cumberland Coal Operations is located in Greene County in the southwest corner of Pennsylvania. The mine and related facilities have been in operation since September of 1977. Production from this mine, U. S. Steel's first commercial coal mining venture, will eventually reach a level of 2.72 million mt of clean coal per year and is totally committed to electric power generation. Cumberland is a slope mine in the Pittsburgh seam and is mined by continuous mining machines and longwall. The coal from the mine is trans- ported by belt to the surface, taken through a rotary breaker for initial preparation, and stored in raw coal silos. It is then processed through the preparation plant and taken to a clean coal silo where it is held for train loading. Cumberland Mine operates its am 28.16 km railroad to transport the coal to the Monongahela River. The unit train consists of thirty-one 90 mt cars. The coal, once loaded on barges, is then shipped to the customer. Cumberland Mine is one of the most modern coal preparation and unit train loading systems in the nation. The preparation plant is de- signed to receive coal from the silos at a rate of 720 at per hour. The +6.35 mm material is screened out and cleaned in a Daniels heavy media vessel with two 3.35 m weirs. Minus 6.35 mm material is fed to sixteen #88 Deister concentrating tables. The cleaned coal from this circuit is dewatered, and all effluents from the mechanical dewatering report to the classifying Cyclone sump for classification through ten 35.6 cm cyclones. The cyclones overflow material (-150 mesh) is processed through two banks of three 8.5 m3 Denver D.R. flotation machines. The cyclone underflow pro- duct (28-1 0 mesh) is processed in two banks of 5 six 2.83 m Denver Sub A machines. The clean flotation product is then dewatered in Bird screen bowl centrifuges, blended with the other clean coal size fractions, and the total plant product further dewatered in a thermal dryer.

Jan 1, 1980

By Zong‑yu Li, Shao‑jian Ma, Xiao‑jing Yang, Jin‑lin Yang, Xing‑nan Huo, Heng‑jun Li

Optimizing and adjusting the particle size composition of grinding products is of great significance for improving economic benefits and resource recovery and utilization. In this study, grinding contribution and quantitative separation of impact and grinding mechanism in cylindrical mill were creatively researched, and the grinding technical efficiency of impact and grinding was coupled to the grinding technical efficiency of grinding in drop-off mode. The results showed that the contribution rate of impact and grinding in grinding in drop-off mode varied with the grinding time. On the whole, the contribution rate of impact action increases with the grinding time and gradually becomes stable, and the contribution rate of grinding effect was just the opposite. Under the experimental conditions, the main contribution of the grinding process is impact action, and the contribution of grinding action is auxiliary. In addition, the contribution rate of impact and grinding effect in grinding in drop-off mode was also related to the feed particle size. The contribution rate of impact effect decreased with the decrease of feed particle size, while the contribution rate of grinding increased inversely.

Aug 3, 2023

By J. Payton

Public Service Company of Oklahoma began burning sub-bituminous coal in December, 1979. Initially PSO had a single source coal supply from Jacobs Ranch Mine, and in 1982 added deliveries from Clovis Point mine. Both are Powder River Basin (Wyoming) coal mines. In 1986 PSO began burning Oklahoma coal to meet Oklahoma's 10% native use law. PSO experienced random s lagging during certain blends of these coals. PSO installed a boiler performance system to help control the slagging problems from the various coal blends, to improve boiler efficiency, and increase total coal consumption.

Jan 1, 1990

By J. Marts

Underground longwall coal mining sections are operated as sealed gobs if the coal is prone to spontaneous combustion. Sealing along the gate roads during longwall face retreat limits the flow of fresh air (oxygen) into the gob and, thus, deprives the spontaneous combustion reaction of oxygen. In a project sponsored by the National Institute for Occupational Safety and Health (NIOSH), researchers at the Colorado School of Mines have used computational fluid dynamics modeling to simulate the flow of gases in sealed longwall gobs. The models were validated using measurements and observations from the field and demonstrate that targeted injection of nitrogen along the gate roads inby the face can be used to control the size and location of explosive methane clouds within the gob and to minimize or eliminate the explosion hazard resulting from the formation of flammable methane-air mixtures.

Sep 1, 2013

By Vinícius Resende Domingues, André Pacheco de Assis, Bernardo Cascão Pires e Albuquerque

"The increasing demand for underground works in urban centers, and in particular the need to build undercrossing tunnels, requires constant evolution in building techniques in order to achieve success and safety. In the case of Brasilia, capital of Brazil, in order to preserve an important avenue (Eixo Monumental), where are located many historical monuments, the construction of a tunnel was envisioned as an option to interconnect the National Stadium (on one side of the avenue) to the Convention Center Ulysses Guimarães (on the other side). The excavation design is comprised of a coverage smaller than one diameter, height of 7.5 m, width of 9.0 m and length of 25 m. In order to enable a negligible influence on the avenue’s usage, the structure is designed as a portico system composed of pipe canopy. In this context, this study presents the portico analytical solution computed with the aid of the software Mathematica and a numerical solution using the software ABAQUS. INTRODUCTION Undercrossing tunnels are increasingly common in urban centers as alternative roads or as access to underground works of large dimensions (stations and parking lots). The geomechanical conditions of the soil mass, not always favorable, and the low distance between tunnel’s ceiling and the surface require intense treatment of the soil massif and execution of a rigid support system. The importance of the road just above the undercrossing tunnel emphasizes the need for a highly competent monitoring system because existing structures require minimum allowable displacement and do not allow the interruption of traffic. The soils that are excavated for the construction of undercrossing tunnels are composed, in most cases, of layers of fill and / or soft soil or weak rock, showing stability problems when subjected to tunneling operations. The combination of low coverage and week ground is solved by soil improvement techniques and strengthening of the excavated cross-section with further advance with the so-called New Austrian Tunneling Method (NATM). Another option is to build structural frames that support the surface. In this research, and based on the context of a case study, we propose the study of the construction technique comprising a portico structure composed of pipe canopy. For this paper, the technical standards used are the Brazilian ones as the case study refers to this country."

Jan 1, 2016

By Osvaldo Bascur

Large metallurgical complexes have more data than a small city and much of it is "real time," changing rapidly as internal and external conditions evolve. As corporations buy and sell assets and reengineer their staff, the structures and tools that were used to understand these data are lost. This results in significant deterioration in the ability to maintain a "smart" operation. The solution is to use the sophisticated new tools built for the Internet so as to leverage information in a familiar browser format that people can use and understand. This paper describes the use of Internet technologies with plant data. Examples are drawn from existing industrial sites. Users must project where this technology will lead - standing still is the most dangerous philosophy and the only one guaranteed to be obsolete. These examples show the way to leverage existing workers with information technology.

Jan 1, 2000

By Frank E. McCall, John K. Marshal, Fred Garcia

Since the advent of longwall mining systems in the United States, mine operators are increasingly relying on methane drainage techniques to supplement the ventilation system. The most commonly used technique is the vertical gob borehole. The number and spacing of vertical gob boreholes per panel is generally based on experience and underground conditions. To design a more efficient methane drainage systems, mine operators must accurately determine methane gas produced. Thus, mine operators must monitor gas flow and methane gas concentration on every vertical gob borehole on active panels at least once or twice during each 8-hr shift. As the mine grows, it is possible to have more than one operating longwall and many vertical gob boreholes. Thus, daily visits to each vertical gob borehole site can become very time consuming. During weekends when methane gas concentrations typically drop because there is no mining activity, borehole sites may not be visited. To obtain accurate gas flow data, a gob borehole monitoring system was designed and constructed by the U.S. Bureau of Mines (USBM). Gas flow, methane gas concentration, gas temperature, barometric pressure, and vacuum pressure of the exhaust fan are the parameters collected by the system. The system also includes circuitry for automatic shutdown of the exhaust fan and an alarm system before an unsafe condition is created. Telemetry components were also integrated into the system to allow for transmission of borehole data to the mine office. As a test, the system was installed and operated on a vertical gob borehole for six months. Test results indicated that intermittent measurements with hand-held instruments from vertical gob boreholes were always higher than gas flows measurements made by the gob gas analyzer system. This paper describes the system components, operational characteristics, and the results of the test program.

Jan 1, 1995

By Shaojun Bai

Siderite ore with high phosphorus content was reduced isothermally at 1,050° C with pulverized coal and different dosages of sodium carbonate. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energydispersive analysis of X-rays (EDAX) were used to characterize the samples. The influence of sodium carbonate on the carbothermic reduction process was investigated. Sodium carbonate and its dosage played a considerable role in the carbothermic reduction. The iron particle size in the reduced ore was below 20 µm, and fayalite was abundant without sodium carbonate additive. With a mass ratio of Na2CO3-to-ore of 5% additive, the iron particle size in the reduced ore was generally above 50 µm, and the diffraction intensity associated with metallic iron in the XRD pattern increased. The effect of sodium carbonate on the phase transformation of fluorapatite during carbothermic reduction was also addressed via thermodynamic calculations and aqueous leaching experiments. The results showed that the fluorapatite was not reduced to P2 at 1,050° C, and a portion of the fluorapatite was converted to soluble phosphate. The reduction of siderite can be catalyzed by adding an appropriate amount of sodium carbonate. This catalytic activity was caused by an increase in the reducing reaction activity of FeO and the acceleration of the carbon gasification reactions. The decrease in phosphorous content in the iron concentrate was attributed to an improvement in the separation of the iron phase from the slag phase when sodium carbonate was added and with the formation of soluble phosphate.

By Lowell T. Harmison

I appreciate very much the invitation to speak with you and the opportunity of bringing you messages from both the Secretary of the Department of Health and Human Services and the Assistant Secretary for Health/Acting Surgeon General of the U.S. Public Health Service. I would like to take this opportunity to congratulate you (the organizers of this Conference) on identifying the critical issues in the field and assembling such a broad array of experts to address them. I would like to present a brief view of the emerging framework for health that puts into perspective some of the aspirations of the Administration and to highlight several points with regard to prevention and occupational health. The goals are: 1. To improve the overall health status of our people. (This has been and will remain the National policy regarding health.); 2. To engage the Nation in the important effort of enhancing public health. (This is not reserved exclusively for the activity of the Federal Government or for State Governments. Public health has to be a cooperative effort that brings together all of the people engaged in the process of serving the people.); and 3. To pledge that health care will not be priced out of anyone's reach because of inflation. (It is clear that there are major tasks of bringing about economic recovery in our country. One aspect of this effort is to guard against the cost of health care not being allowed to rise beyond the reach of persons who need that care.) "How will these goals be achieved and what must change in the delivery of health and medical care in our society?" There are a number of real issues as well as perceptions that adversely affect the attainment of these goals: First, The cost of medical care is soaring and the public, industry unions and other elements of our society are becoming concerned. (They recognize the problem and are demanding a solution.); Second, There is a growing concern about the priorities that have been set. (For example, the evidence that preventive interventions are the most effective approach is overwhelming, yet medicine has not yet given that a high priority.); and Third, There is the perception that physicians do too much to too many people at too great a cost and that too much and too costly technologies are used. In view of the perceptions, we all must accept some changes and the challenges that needed changes will bring. A month before the new budget went to Congress, President Reagan went on nationwide television and told the American people that, "It is time to recognize that we have come to a turning point and we are threatened with an economic calamity of tremendous proportion and the [old business as usual treatment can't save us. Together we must chart a new course]." Now eight months down the road from this and a long Spring and Summer of discussion both within the Executive Branch and in the Congress, many plans and programs and concepts have emerged. The new course has been charted and the turning point has been made. Business as usual has been put aside and the Administration's leadership has been stretched and tested in putting forth a better approach with the reality that money is tight and that old habits of delivering care are difficult to change. The Congress has now given us a look at a new health budget that takes into account some of the harsh economic realities and that does make allowances for the persistence of familiar behavior. Against this background, it is now possible to begin addressing ways to provide health services to people at a price the Nation can afford to pay. There are without question difficult decisions involved but the Administration is committed to supporting and improving health care in America. It has been the President's contention that one of the principal causes of the inflationary spiral in the country was the steady and indefensible growth of the Federal budget. The problem stems from the fact that we have been living well, but beyond our means for nearly 30 years. Now we are discovering that there is a bottom to the barrel after all. It is possible for our society to run out of things like energy (oil), water or money. The health bills must be paid -- by Government, by insurance, by parents or by someone. Each year with a bigger shopping list and more money to spend the Federal Government went into the marketplace to buy. This action altered the

Jan 1, 1981

By Kanaan Hanna, Mir Heydari, Dipack Sengupta, Gordon B. French

This article, first in two, discusses the safety, technology, and economic impact of eliminating safety fuse from metal and nonmetal mines. It is based on operation and manufacturer experience over the past five to 10 years. If safety fuse is eliminated, blasting accidents will decrease. There should be only limited technical impact. The economic impact will be minor for large operations, but will be significant enough for small operations that some will likely close rather than change. Most mines would probably change over, with the market absorbing the extra cost. Elimination of safety fuse would obviously have an impact on the two safety fuse manufacturers. One manufacturer produces an alternative system and would be unaffected. The other, however, will be affected if it does not change its production strategy. From the standpoint of employment and production, abolishing safety fuse will have a very minor effect on the mining industry as a whole. This article discusses the current use of initiation systems, incidence of accidents, and fuse consumption. Next month, part two describes the economic impact of eliminating safety fuse on the mining industry and manufacturers, and presents an economic analysis of the initiation systems. Introduction The objective of this study was to determine the safety, technology, and economics of eliminating safety fuse from metal and non-metal mines. There were five major tasks: • Studying initiation-related accidents from the Health and Safety Accident Center (HSAC) data file; • Visiting mines, collecting relevant data, and interviewing mine operators; • Establishing the trend in safety fuse consumption and type of users; • Corresponding with fuse manufacturers, domestic and foreign; and • Developing an idealized blasting cycle to evaluate the possible economic impact of safety fuse elimination on large and small operations. More than 450 explosives-related accident reports have been screened and analyzed by investigating HSAC files. These reports have been studied and classified according to the four initiation systems, size and type of mines, and time and frequency of accidents from 1973 through 1978. Twenty-four mining operations were visited to obtain supporting data for this study. Mine personnel were interviewed to determine attitudes about safety fuse and alternative detonating systems. This article decribes available data. It also attempts to provide information that can be used to answer such questions as: • Is the use of safety fuse (an antiquated detonation system) a major cause of mining accidents? • Are alternative systems available that could result in fewer in-juries to miners?

Jan 1, 1984