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By Lloyd A. Morley

This eight-chapter document is the second volume of a two-volume report that presents a comprehensive outline of coal-mine electrical power systems from theory to practice. Together, the two volumes contain the vital aspects that go into planning and designing a mine power system. Building upon Volume I, the subject of protective equipment and relaying starts Volume II, first as an introduction in Chapter 8, then by a treatment of device selection in Chapter 9. Chapter 10 continues system protection in terms of transients and overvoltages. Chapter 11 describes the design of major power equipment, including power centers, switchhouses, and substations. Solid-state applications in mining are given in Chapter 12, and batteries and battery charging are discussed in Chapter 13. Chapter 14 covers electrical-equipment in hazardous locations of mining operations. The report concludes with Chapter 15, a discussion of electrical maintenance as well as some specific mine electrical problems. Information on surface and underground use is included in all these chapters. An index finishes the documentation and is cross-referenced to both report volumes.

Jan 1, 1982

By R. R. Sayers

The increasing use of hydrogen fluoride (annual consumption now exceeds 500,000 pounds (1)4/) directly and its occurrence as a byproduct of the utilization of fluorine compounds in the mineral industries, especially in metallurgical processes and in the refining of petroleum products, has aroused interest in its toxicity, and a brief review of the literature, with special reference to the hazard of poisoning in the mineral industries, seems to be opportune. Recently, residents in the vicinity of aluminum plants have been complaining of injury to livestock and vegetation as well as to their own health from the gases discharged into the air during operation of the plants, hydrofluoric acid gas apparently being the offender. The comparatively recent utilization of hydrofluoric acid in the alkylation process for the production of high-octane gasoline has raised the question of the hazard of poisoning in the petroleum Industry. In addition, the use of fluorine-containing refrigerants has extended the potential al exposure outside of industry (2).

Jan 1, 1945

By Robert J. Shanley

The computer program, HYBMODE, has been developed to meet the need for a fast and economical method for clustering data points on the sphere. The algorithm used in this development is an extension of D. Wishart's one-level mode analysis. The program can be used to cluster either vectorial or axial data; it is currently being used by the Bureau of Mines to cluster fracture orientations.

Jan 1, 1974

By C. J. Sullivan

"The outlook for supplying the world's metal needs in the next twenty-five years is good, although in several cases basic costs are likely to increase with rising demand. Metal prices calculated at a constant dollar from 1900 to the present show that for nickel, copper, silver, lead, zinc and tin, prices -and presumably production costs -fell from 1900 to the early 1930s. Since then, they have generally risen, apparently reflecting some depletion in relation to demand. This tendency has been accentuated since the post-World War II adoption of managed, full-employment, growth economics, which have resulted in a sharp escalation in world demand for metals. (Abandonment of such policies, apparently now under consideration in North America, would, of course, affect the pre-dictions of this paper.) Nevertheless, metal prices generally are still below those prevailing in 1900. Exploration potential exists for disseminated ores of many metals still thought of as characteristic of lode and vein deposits. These include uranium, silver, gold, tin and nickel and, to a lesser extent, lead and zinc. Considering the discovery potential for some principal metals in relation to expected demand and prices, I would tend to rate them as follows: molybdenum, zinc, lead, uranium, silver, gold, tin, nickel and copper."

Jan 1, 1970

This Kaiser Engineers report on the feasibility of surface mining on the North Slope of Alaska has considered the quantity and quality of the North Slope deposits with attention paid to the economic, technical, and environmental constraints of the mining systems suggested for the three candidate minesites at Kukpowruk River, Elusive Creek, and Kuk River. Site selection, based on coal rank and quality as well as seam thickness and geometry, also considered demonstrated and hypothetical reserves relative to three mining systems (dragline, shovel, dragline and shovel), mining equipment requirements, infrastructure, and transportation relative to the Arctic environment and costed for potential markets. Throughout the report the delicate permafrost environment has received particular consideration. Recommendations based on the technical, economic, and environmental feasibility of mining the coal deposits of Northern Alaska by surface mining techniques have resulted in two conclusions: 1. The coal deposits can be mined with currently available technology; 2. It is uneconomic to mine these coals given current coal resource estimates, costs, and market conditions. A literature survey is included in appendix.

Jan 1, 1977

The United States Bureau of Mines is establishing a computerized mineral inventory system to help the Federal Government appraise its mineral position and prepare programs insuring against critical shortages of materials. This system, called the Minerals Availability System (MAS), is a component of the Bureau's minerals intelligence function designed to conduct and maintain an inventory of minerals important to the Nation. The MAS defines the physical and commercial availability of the mineral resources. Known resources are evaluated and classified by deposit for entry into a computer storage and retrieval system. An integral concern of these evaluations is the cost of mining and beneficiating the ore contained in specific deposits. To meet this concern, a cost handbook was developed as an aid to preparing feasibility-type estimates for capital and operating costs of mining and primary beneficiation of various types of mineral occurrences. Cost data, obtained from U.S. and Canadian companies, were used as the basis of this handbook. The handbook presents cost curves and equations for each component of the mining and beneficiation process. Factors for each cost component are also given, thereby allowing the updating of cost for time, geographic location, labor rates, and mining and milling conditions. Included in the latter conditions are items such as the length of haul, need for rock bolts, and a rock work index for ores and rocks of various hardnesses. 1.2. USE OF THE HANDBOOK Using the handbook a feasibility-type estimate falling within 25% of expected actual cost is obtainable by summarizing cost components. This handbook should not be used to determine the cost of any single component of a mining or beneficiation system, as any single component may not fall within the 257 limit. It must be understood that anyone who uses the handbook must have a comprehensive knowledge of mining and processing technology and cost estimating procedures. The handbook was intended to be used internally by the Minerals Availability System. Because

Jan 1, 2012

By B. M. O'Harra

Zinc smelting is frequently termed a ba.ckward art. The term is hardly true, for great progress has been made in recent years in the design and in the thermal efficiency of the retort furnace, in the quality of retorts, in the recovery of zinc, and in the ability to treat more impure and complex ores. The fact remains, however, that the peculiar physical and chemical properties of zinc have delayed such immense advances-large smelting units, high recovery, lowunit costs, and ability to treat low-grade ores-as have been made in the metallurgy of lead and copper. In current retort-smelting practice, the ores, if carbonates, are calcined to remove carbon dioxide; or, if sulphides, are roasted to remove sulphur. The sulphur must be eliminated as completely as possible, usually to less than 1 per cent. This means that the roast must be continued for a long time at a high temperature, with resulting high cost and small capacity per furnace. The roasted ore is mixed with about 50 per cent of its weight of reducer, which may be fine coke, anthracite, or nonbituminous coal. This mixture is charged into horizontal fire-clay retorts. The retorts used in this country are about 8 inches in internal diameter by 4 feet in length and hold 50 or 60 pou~ds of ore. The diameter of the retort is limited by the tirrie required for the heat to penetrate to the center of the charge; the length by the strength of the retort, which at the high temperature employed can not support the weight of the charge if the span is more than about 50 inches. The retorts are heated externally by coal, natural gas, qr ·producer gas to a temperature of 1,200° C. or more. The zinc oxide is reduced to zinc, which is volatile at this temperature, and passes into a conical fire-clay condenser. attached to one end of the retort, where it conde_nses to liquid zinc and is removed. Twenty-four hours are required for distillation, and because of the low heat conductivity of the retort walls 11.nd of the ore charge itself, the heat efficiency even of the most modern regenerative furnacei;; is only about 12 per cent. The retorts have a short life, 30 to 6Q days, at the high temperature required-; zinc losses are heavy, usually 10 per cent or more; and the proportion of impurities in the retort charge must be carefully controlled to prevent the rapid corrosion of retorts. For these reasons, much work has been done in an e:ff ort to, find cheaper and more efficient methods o.f recovering zinc from its ores. Various methods have been proposed for smelting in the blast furnace. Some of these contemplated the production of zinc vapor and its condensation to liquid; others attempted to produce liquid zinc directly by smelting under pressure. It is now realized that fundamental difficulties render these proposals impracticable. The electric furnace for smelting offers obvious advantages in the way of the efficient utilization of energy, large units, easy attainment of high temperatures, and the possibility of treating complex ores. E. H. and A. H. Cowles first suggested a design for an electric furnace for the reduction of zinc ores and patented their process in 1885. Their attention was soon directed to other uses for their furnace and nothing further of importance was done in the electric smelting of zinc until about 1900. Several investigators then started work upon various processes and had more or less success. The chief difficulty they encountered was the impossibility of obtaining more, than a small amount of the zinc as liquid metal because most of the zinc vapor condensed as blue powder. Interest in the electrothermic metallurgy of zinc increased, many patents on processes and furnace design were taken out, and the literature on the subject grew, until in 1914 and 1915 the problem seemed to be approaching solution. About this time the hydrometallurgy of zinc, the development of which had been lagging somewhat behind that of the electrothermic metallurgy, sprang into the limelight and a commercial process was soon perfected. This rapid development, perhaps aided by the war premium on the high-grade spelter produced by electrolytic deposition, distracted attention from electric smelting to some extent, though progress continued. With the perfection and standardization of the electrolytic process has come a better realization of its limitations, especially the necessity for large-scale operation ·and the difficulty of obtaining high extraction. Because of these limitations the electrothermic metallurgy of zinc still has a field of its own and in fac-t promises to become a strong competitor of both hydrometallurgy and retort smelting except under conditions highly favorable to the latter methods. Because of the imperfections of the retort and electrolytic processes and the promise that the electric furnace offers in overcoming these imperfections, the. United States Bureau of Mines, in cooperation with the Missouri School of Mines and Metallurgy, has undertaken a study of the electrothermic metallurgy of zinc.

Jan 1, 1923

By Martyn F. Roetter

The objectives of the work described in this report are to determine the communications requirements and need for communications, both for voice and control, on longwalls, and to make recommendations for longwall communications equipment and systems. These recommendations are designed to guide the future development of longwall communications. Information necessary for the accomplishment of this work has been gathered by a series of visits to longwall mines and discussions with longwall mine operators, as well as with suppliers of longwall communications and mining equipment and with Bureau of Mines personnel. In addition, it has proven possible, through personal interviews and literature evaluation, to gain an understanding of the experience and attitudes towards longwall communications in countries where longwall mining is far more widespread than in the U.S., namely the Federal Republic of Germany, the United Kingdom, France and Belgium.

Jan 1, 1976

By Richard H. Spencer

The purpose of this program was threefold: (1) to identify the symptoms of poor or inadequate performance of trolley carrier phone systems; (2) to assess the root causes of performance difficulties and classify them on the basis of equipment, coupling, or transmission; (3) to propose, analyze, test, evaluate and verify means of overcoming performance difficulties. Based on interviews and discussions with knowledgeable persons, laboratory experiments, and in-mine measurements, it was determined that the major impediment to good carrier phone system performance is the extreme signal attenuation found on the trolley wire/rail largely due to the many bridging loads. Three means are identified to help overcome the performance difficulties: the low impedance trolley wire, a method of improving performance by capacitively loading the transmission line; the dedicated wire, a low-loss means of extending trolley signal coverage; the use of isolators to remove the offending bridging loads at the carrier frequency. Other subjects treated in the report are design reviews of hardware, guidelines for the use of information in the report, recommendations, and a description of a probe for measuring trolley wire current.

Jan 1, 1977

A symposium was held on January 30 and 31, 1973, at Pittsburgh, Pa., to review the state-of-the-art in designing and utilizing diesel-powered equipment in underground mining. The Health and Safety Activity of the Bureau of Mines sponsored the symposium with major assistance from the following four participating organizations: The American Mining Congress J. Allen Overton, President The United Mine Workers of America Arnold R. Miller, President The National Independent Coal Operator's Association Cloyd D. McDowell, President The Bituminous Coal Operators' Association, Inc. Guy Farmer, President Seventeen papers were presented during four half-day sessions devoted to the general subjects of the diesel engine, the place of the diesel in underground mining, health protection using diesels underground, and maintaining safety of diesels underground. Eleven of the speakers were from industrial organizations here and abroad; one represented the Provincial Government of Nova Scotia; two were with the Department of Health, Education, and Welfare; and three reported on Bureau of Mines work related to diesels.

Jan 1, 1975

Surface mining and reclamation of a southeastern Ohio site with sandstone-shale overburden resulted in (as compared to premining levels): 1) runoff volumes and peak rates that increased by a factor of from 2 to 10 during mining and after reclamation, 2) destruction of the "aquifer" perched on the underclay of the mined coal bed and gradual, but, as yet incomplete redevelopment of this aquifer after reclamation, 3) no immediate effect on another, lower perched "aquifer", 4) up to 100 times greater sediment concentrations in runoff. Results were influenced by increasing annual precipitation amounts through the period of record; 1978, 1979, and 1980 (postreclamation years) experienced precipitation amounts approaching or exceeding long-term normalcy for the area. Part of the reason that the site produced more runoff after reclamation than before mining is that the premine condition was one of an open, porous soil under woodland, while the postreclamation condition was one of a compacted, bulldozed soil. Sediment concentration results were influenced by failure of the postreclamation erosion control system and by a series of detention reservoirs above the stream monitoring station.

Jan 1, 1983

These proceedings consist of papers presented at Bureau of Mines Technology Transfer Seminars in August 1983 for the purpose of disseminating recent advances in mining technology in the area of large mobile surface mining equipment safety and health. The Bureau of Mines conducts several of these seminars each year in order to bring the latest results of Bureau research to the attention of the mining industry as quickly as possible.

Jan 1, 1983

By Robert L. Lagace

The purpose of the work reported herein was to investigate whether available telephone multiplexing equipment offered a means to rapidly upgrade the traffic-handling capacity of present mine telephone systems and provide for selective calling for safer and more efficient mine operation. Common sense was used to decide whether or not an item could be termed "available." Since conventional telephone gear is not designed to interface pager phones for example, existing shelf items would require adapters to compatibly interface these two types of gear for independent operation over the present single twisted pair used in mines. These and similar small items were allowed, but if a system required any extensive design work to adapt it for the mines, we ruled it "not available."

Jan 1, 1975

By D. J. Parker

Because of its convenience and availability, natural gas (and to a much less extent manufactured gas) in being used more generally throughout the country for domestic and industrial purposes. With this use, specific and little-recognized hazards have arisen owing principally to the fact that the public and the consumer lack knowledge of the explosive property of this fuel. During the past 8 years gas explosions hove occurred in public and private buildings with loss of more than 300 lives and injury to many others. Such appalling catastrophes can and will be prevented if and when the necessary precautions are taken in the construction of buildings and the installation and maintenance of gas lines and gas appliances, plus adequate supervisions inspection, and education.

Jan 1, 1941

By Paul B. Queneau

Formulation and commercial utilization of solid-waste incinerator slag by-product is the focus of this paper. Particular attention is given to iron aluminosilicate melts having compositions similar to that of nature's basalt The earth?s crust can be viewed as an environmental laboratory for predicting stability of various silicates; small-scale laboratory experiments are necessary to confirm findings there from. An ideal slag consumes flux additives at acceptable cost, is compatible with furnace refractory, flows readily from the furnace, and has physical properties suitable for its commercial utilization -all within the critical constraint that the slag is environmentally stable. Examples of successful solid waste slagging practice, including tonnage, utilization and pricing, are provided from metallurgical and waste treatment operations of North America. Western Europe and Japan.

Jan 1, 1991

By A. Halim, A. Martikainen, S. GYAMFI

This paper outlines a unique case of the development of strategies to reduce ventilation and heating costs in Konsuln iron ore mine in northern Sweden. The mine, located just south of Luossavaara-Kiirunavaara Aktiebolag’s Kiruna iron ore mine, was developed as a test mine from 2018-2020 for the Sustainable Underground Mining (SUM) project. Besides functioning as a test mine, Konsuln also contributes to ore production. The existing mine ventilation system was designed for the current production rate of 0.8 million tons per annum (Mtpa). There is a plan to increase this rate to between 1.8 and 2.0 Mtpa.

Sep 30, 2021

Two different techniques were used to make measurements of the absolute value of electromagnetic noise in an operating coal mine, Robena No.4, located near Waynesburg, Pennsylvania. One technique measures noise over the entire electromagnetic spectrum of interest for brief time periods. With present instrumentation, the spectrum can be covered from 40 Hz to 400 kHz. It is recorded using broad-band analog magnetic tape, and the noise data are later transformed to give spectral plots. The other technique records noise envelopes at several discrete frequencies for a sufficient amount of tine to provide amplitude probability distributions. The specific measured results are given in a number of spectral plots and amplitude probability distribution plots. The general results are that at frequencies below 10 kHz, power line noise within the mine is severe. Impulsive noise is severe near arcing trolleys, and at lower frequencies near any transmission line. Carrier trolley phone signals and harmonics are strong throughout the mine whenever the trolley phone is in operation. Additional information beyond that included in this report may be obtained from the authors, who are with the Electromagnetics Division of the National Bureau of Standards.

Jan 1, 1974

By Lloyd A. Morley

This seven-chapter document is the first volume of a two-volume report that presents a comprehensive outline of coal-mine electrical power systems from theory to practice. Together, the two volumes contain the vital aspects that go into planning and designing a mine power system. After a short introductory chapter, Chapter 2 discusses the history of electrical use in mining and introduces "typical" mine- power-system arrangements. Chapter 3, 4, and 5 supply basic information on electrical theory, circuit analysis, and motors. Next, the Grounding and Distribution Chapters detail unique aspects of mine power systems. Elements of surface and underground use are included in all these chapters. An index concludes Volume I and is cross-referenced to both report volumes.

Jan 1, 1982

By Edmund S. Leaver, R. S. Dean, T. L. Joseph

The metallurgy of manganese has developed along the lines of iron metal¬ lurgy. Enough high-grade ore has Been available so that by reduction with carbon it could be turned into an iron-ma.nga.nese alloy and a slag containing some 9 to 15 percent manganese. More siliceous ores have been smelted in the blast furnace to form iron-silicon-manganese alloys called spiegel. When lower-grade ores came in for serious consideration, which lias only been since l°l4, two types of processes received the most consideration — hydrometallurgical processes to produce a concentrate which could be smelted like the higher-grade ore and processes involving concentration of the manga¬ nese from manganiferous iron ores by preferential reduction of the iron (184)1. Special chapters in this bulletin are devoted to the production of ferro¬ manganese from ore, the hydrometallurgy cf manganese, and the Bureau of Mines modification of the preferential reduction process. Other methods of producing manganese alloys from low-grade or refractory ores have been suggested and may find future application. Manganese has a very high affinity for sulphur and is particularly adaptable to concentration by matte smelting. According to Betts (26), manganese silicate may be smelted with pyrite to give manganese sulphide and iron silicate. This method would be applicable to concentration of either the silicate or carbonate ores. The sulphide, once obtained, could be roasted to oxide and reduced in the usual way. Another possibility for the production of manganese from silicate ores involves their reduction by silicon or manganese silicides. Swedish Patent 52290, February 25, 1925. covers the reduction of a slag rich in manganese by silicon-manganese alloy containing more than 10 percent silicon, Joseph H. Brennan (38.) describes the concentration of manganese iron ores by partial reduction with silicon. Beckett (7,4,19) describes the reduction of manganese dioxide with a manganese silicide for the production of standard ferromanganese. Beckett gives as a typical alloy, manganese 64.4, silicon 24.6, and as a typi¬ cal ore, 5S.5O manganese as MnO^. The product of the reaction between these two is 80.11 percent manganese and 1.22 percent silicon.

May 1, 1934

By Grant R. Brown

This report presents the results of a study examining the relationship between supervisor characteristics and performance in underground coal mines, The specific objectives of the research include; document tasks performed by first-line supervisors during a normal shift; explain why supervisors carry out their duties as they do: identify salient characteristics of effective first-line supervisors; and formulate criteria for selecting and developing candidate supervisors. To accomplish the study objectives, on-site observation and data collection was carried out at 13 underground mines in Illinois, Ohio, and Pennsylvania. One hundred thirty-eight first-line supervisors were observed during a full work-shift and discussions with the supervisors and the mine superintendent were held during the course of the visit. The observational data from the study provide a detailed description of what supervisors to during their shift. The report begins with an introduction discussing the problem being studied and objectives of the research. The literature related to supervisor selection is then reviewed. The following section describes the research design including data collection procedures and statistical methodology used in the study. The next sections present the analysis of mine, section, crew, and supervisor characteristics. The report concludes with a discussion of the results of the study and recommendations concerning supervisor selection and development.

Jan 1, 1987