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By Lloyd A. Morley

This Bureau of Mines publication presents a comprehensive review of mine electrical power-system theory and practice. It discusses fundamental theory and the vital aspects to be considered in planning and designing mine electrical power systems. The report is divided into three major sections. The first presents the history of electricity in mining and the fundamentals of electrical phenomena and components. The second focuses on power-system components: motors, grounding systems, cables, and protective equipment and devices. The final section includes mine power-center equipment, switchhouses and substations, batteries, and mine maintenance.

Jan 1, 2003

By H. B. Humphrey

[EXPLOSION of gas and dust in coal mines, have caused death t lid injure to mines, and destruction of workings in all countries where coal is mined underground. In the United Stales the first reported explosion wits in Min; explosions have continued to the present. The danger to film ill it mine When an explosion occurs in not always measured by the violence created or by their nevi lies, to the area through which flame and Violence extend. As many, perhaps more, risen have died from gases and lade of oxygen (known as "after-damp") than have been killed by the blast and hart. Me explosions often are caused by it combination of factors, including concentration of methane in air, formation of clouds of dust, and the presence of a flame or spark. These explosion factors have varied with changes ill milting method and practises over the years, but the basis causes have always been the salve. Understanding of the causes and to acceptance of ways to guard against explosions and their effects have been slow to spread from investigates to officials and Own to bosses and miners. To a considerable extent there hats lawn a belief that explosions were a joining risk but might hr, put oil hut could not be presented. Such belief is based on the human failure to maintain and observe necessary precautions. These failures, caused by inertia to change, carelessness, or reliance on continuance, of past explosion-free years, are being reduced in number and effect by education of miners and supervisors and acceptance of higher prevention standards.]

Jan 1, 1959

By D. A. Reynolds, J. D. Davis

"This work was begun in l928, with the cooperation of the American, Gas Association, and the Association contributed financial aid for that year and for the 4 years following. In 1933 financial aid was discontinued, but the Advisory Committee, under the able, Chairmanship of J. S. Haug, has continued to function through the years to the present date. Mr. Haug's annual reports have been published in the Proceedings of the American Gas Association. The purpose of this paper is to bring the index of coals tested by the Bureau of Mines-American Gas Association (EM-AGA) method up to date, to discuss development of auxiliary tests, and to outiline the uses to which the methods have been put in promoting the war effort.COALS TESTEDThe test methods developed with the advice of the Advisory Committee had been applied to 66 coals up to 1942, and an index giving the serial number, origin, and analyses of these coals was published as Bureau of Mines Technical Paper 637. Since this paper was published, 20 additional coals have been tested; the source and analyses of these coals are given in table 1. The table also refers to publications that have been issued. Complete series of tests at high, medium, and low temperatures,have been made on most of these coals, and blending tests with 20 and 30 30 percent of low-volatile coals have also been made at 900°C.; however a few low- and medium-volatile coals (60, 70, 74, 79, and 80) were bested,at high temperatures only. Those coals were mined in eastern Oklahoma and western Arkansas. The test work included low- and high-temperature assay tests, petrorraphic analyses, and plasticity tests since its inception; and for the last 20 coals of the series, expansion and oxidation tests have been made where applicable."

Jun 1, 1944

By George A. Morgan

The production and processing of crude petroleum and natural gas are the dominant economic sectors of the Middle East. The 15 countries that constitute the region accounted for 28% of world crude petroleum output, 17.2% of world natural gas plant liquid production, and 5.3% of world dry natural gas production. Only Cyprus and Lebanon were not crude petroleum producers. About 66% of total world crude petroleum reserves and 31 % of total world natural gas reserves are in the Middle East. Transportation and port facilities in the region are geared to expediting efficient and rapid shipment of these materials. Export sales of these fuels provide funding for further diversification of the mineral industry. Additional development of downstream facilities for producing energy-intensive metals such as aluminum and byproducts of the fuels such as petrochemicals and fertilizers can be expected. Earnings from the industry are also channeled by several Governments in the region to mineral industry projects in Africa and elsewhere. Several countries in the region own major petroleum refineries and distribution facilities worldwide. Petroleum prices rose overall during the year owing to the invasion by Iraq of Kuwait in August 1990. Output from both countries, the fourth and fifth largest producers, respectively, in the Middle East, was negatively affected by the war. Kuwaiti crude oil wells and pipeline facilities suffered extensive war damage while exports of petroleum and petroleum refinery products by Iraq ceased owing to a U.N. embargo. The embargo also impacted Jordan, an exporter of phosphate and potash. Shipments of crude petroleum by pipeline from Iraq through Saudi Arabia and Turkey and by vessel through the Persian Gulf were terminated. However, the loss in production from Iraq and Kuwait was more than made up by accelerated output from other Middle East and world producers. Saudi Arabia, in particular, with its excess production capacity, accounted for the largest portion of the increase.

Jan 1, 1992

By G. R. Hopkins

For several years prior to about the middle of 1928 both the number and capacity of natural-gasoline plants showed a steady increase; this resulted from a material gain in the supply of casinghead has due to the discovery of a number of flush fields with relatively high gas-oil ratios. From 1928 to date some form of proration has been continually in force, with a consequent curtailment in the supply of wet gas. This decline in available gas and a severe decrease in prices, due largely to the increasing competition of light refinery products, has eliminated virtually all of the weaker units during the last 5 years, with the result that the number of plants declined from 1,155 on January 1, 1928 to 19035 on January 1, 1930, to 909 on January 1, 1932, and then to 859 on January 1, 1934, The struggle of the small high-cost producers to exist is illustrated further by the trend in the number of shut-down plants, which has increased from 36 on January 1, 1930 to 100 on January 1, 1932 and to 128 on January 1, 1934. The increase in the number of plants prior to 1929 resulted in a material gain in the total capacity, but the decline in number between 1929 and 1932 was not followed by a corresponding decrease in capacity, as gains resulting from the construction of a few very large plants overbalanced the loss due to the dismantling of a large number of small ones. However, the low prices of 1932 and 1933 supplied little incentive for new construction, and the total capacity declined in approximately the same ratio as the number. Thus the total capacity declined from 11,387,000 gallons daily on January 1, 1932 to 13,060,000 gallons daily on January 1, 1934, Of the latter 9,181,000 gallons (91 percent) represented the capacity of the operating plants and 679,000 gallons (9 percent) the capacity of the idle plants.

Jan 1, 1934

By F. E. Spencer

Calculated equilibrium data are presented for three phases in the flue gas stream from a hypothetical open cycle MHD generator. A typical coal is "burned" with 1.0 gram-mole K2O seed per kilogram coal and with 101 percent of stoichiometric air. Tables of composition and the overt thermodynamic properties, enthalpy and entropy, are given for the temperatures 2200 (-100) 1100 kelvins, pressures 1.0 and 1.5 atmospheres, and slag rejection figures of 90 and 75 percent.

Jan 1, 1973

By Joseph A. DeCarlo

The rapid growth of the organic chemical industry in the United States and abroad has focused attention on the future raw-material sources for this important industry. Chemical products are essential to modern civilization; and millions of tons of organic chemicals are used annually, ranging from basic raw materials to finished chemical products such as drugs, cosmetics, and soaps. Hundreds of chemical products are made directly or indirectly from coal, but in this report "coal chemicals" will be limited to crude tar, crud light oil, and ammonia recovered in the high-temperature carbonization of bituminous coal and the important principal products obtained by processing these materials. Specifically these include benzene} toluene, xylene, naphthalene, creosote oil, tar acid oil, pitch, and ammonium sulfate. Therefore the term "coal chemicals", wherever used in this report, includes only these products and does not include the secondary or intermediate products such as styrene, synthetic phenol, aniline, phthalic anhydride, or finished products made from these, such as synthetic rubber, plastics, and dyes. The United States leads the world in production and consumption of coal chemicals. In the past five years nearly one-fourth of the total output of coal-tar crudes in the world was produced in the United States. Consumption of some of the more important products derived from these crudes such as benzene, toluene, xylene, and naphthalene, however, ranged from about one-third to one-half of the world total because of imports and production of benzene, toluene, and xylene from petroleum. The synthetic organic chemical industry of the United States was established during World War I on chemical raw materials obtained by the high-temperature carbonization of bituminous coal but this source of supply currently furnishes less than 40 percent. More than 60 percent of the chemical raw materials used to produce organic and inorganic chemical is supplied by the petroleum industry and production of petrochemicals is rising rapidly.

Jan 1, 1960

By Th. G. Sahama

This paper contains some new thermodynamic data for silicates in the series Mg2SiO4-Fe2SiO4 and MgSiO3-FeSiO3 and Lives the result: of a thermodynamic attack on the problems of stability end paragenoses. Although some data are lacking, satisfactory agreement with mineralogical and petrological observations is indicated.

Jan 1, 1949

By Ferdinand Roehlich

An evaluation of the use of manually activated, installed,. dry chemical fire protection systems on underground metal and nonmetal mine vehicles is described. In addition, an assessment of the possible health risks posed by the dry chemical extinguishing agents used in such systems is provided. Work involved installation of fire protection hardware on an operating piece of underground metal/nonmetal mine equipment and, via actual fire tests, a determination of the effectiveness of the hardware in extinguishing on-vehicle fires. Two fire protection systems were installed on a Caterpillar 988 front-end loader in St. Joe Mineral's Fletcher mine, near Viburnum, Mo. Both a fully pressurized Safety First CM-20 and a nonpressurized cartridge actuated Ansul A-101 were installed for comparative purposes. Both systems operated satisfactorily during an 8-month endurance trial period which preceded the actual fire tests. Each system was able to extinguish an 18" x 4" class B test fire placed in the engine area of the machine. The health hazards analysis of dry chemical powder consisted of a detailed search of published literature relating to these multipurpose agents. This data was verified via a controlled laboratory analysis of two monoammonium phosphate based powders (Safety First Unikem and Ansul Forey) and an analysis of air samples collected at various locations on the test vehicle during the fire tests. Although the powder was found to be nontoxic, two potentially dangerous thermal decomposition products were identified--ammonia and phosphoric acid. However, later analysis indicated that an operator would not be exposed to dangerous concentrations of either compound if he were to remain outside of the powder cloud. A "Selection and Use Manual for Manually Activated, Fixed Fire Suppression Systems on Underground Metal and Nonmetal Mining Equipment" was prepared both as an, appendix to the report and for distribution under separate cover.

Jan 1, 1977

By M. M. Tilman

The Bureau of Mines conducted research to determine the feasibility of strengthening experimental magnesium-base sheet alloys by strain softening induced by controlled cold rolling followed by selective heat treatment. Relatively small alloying additions having potential for producing strain softening were selected from metals that are readily avail-able. Tensile properties comparable to minimum properties of the most commonly used magnesium-base sheet alloy AZ31B, in the H24 condition (strain-hardened and partially annealed), were obtained in an Mg-IMM (mischmetal)-O.5Mn alloy after strain-softening rolling followed by heat treatment. Tensile properties of the experimental alloys in certain conditions are also compared with minimum tensile properties of other standard magnesium sheet alloys. Incidental to the principal objectives, apparent superplastic behavior was observed in three experimental magnesium-base alloys containing MM, MM plus manganese, and MM plus zirconium.

Jan 1, 1985

The investigations reported herein comprise preliminary studies to evaluate large scale mining systems adaptable to the thicker oil shale deposits in the deeper central portion of the Piceance Creek Basin. The studies include an evaluation of the geology, hydrology and resources of the Basin., evaluation of a potential prototype mine site, synthesis of rock mechanics data on Green River Formation oil shale, selection and preliminary design and cost evaluation of six potential mining systems and a ranking analysis to aid in selecting the most promising system. Results of the ranking analysis indicate the following four systems to be most promising for large scale underground oil shale mining: - Chamber and pillar (using spent shale backfill) - Sublevel stoping with spent shale backfill - Sublevel stoping with full subsidence - Block caving with LHD's Recommendations for phase II are to investigate the above systems in greater detail, refine present cost data, and perform economic evaluations of oil shale mining using these systems.

Jan 1, 1975

By John J. Mulligan

The Bureau of Mines investigated the tin deposits of the Cape Mountain area during July and August 1962 to test the effectiveness of detrital-cover sampling in permafrost areas as a relatively cheap and simple means of guiding mine development and exploration. Results indicate that systematic detrita1-cover sampling can be used effectively to delineate obscure deposits with sufficient accuracy to permit sampling with a minimum of trenching or drilling. Extensions of known outcroppings were traced in sufficient detail to guide lode sampling and several previously unknown tin-bearing lodes were found and sampled. Lode sampling was limited to the minimum needed to establish the reliability of detrital-cover sampling results. The results of previous lode and placer investigations are summarized and detrital-cover sampling methods and results are described in detail.

Jan 1, 1966

By Ronald P. Hollenbeck

The value of mineral production in Alabama increased 1 percent above the record high set in 1965. Alabama ranked second among the States in the production of bauxite, third in the production of masonry cement, native asphalt, and scrap mica, sixth in the production of portland cement, ninth in the production of iron ore, and tenth in the production of lime. The mineral industry of Alabama was dominated by the mining and processing of coal and stone, the manufacturing of cement, and the production of crude petroleum. These industries accounted for 87 percent of the State's total value of mineral production, compared with 85 percent in 1965.

Jan 1, 1967

By J. T. Matson

This paper describing the mining practice at the Pecos mine of the American Metal Co. of New Mexico, a subsidiary of the American Metal Co., Ltd., is one of a series being prepared by the Bureau of Mines on mining methods, practices, and costs in the various mining districts of the United States. The mine is producing about 18,000 tons per month of zinc-lead-copper ore, chiefly by the square-set and cut-and-fill methods. Costs are given for 1927, 1928, and 1929, the whole producing life of the mine to date.

Jan 1, 1930

By B. M. O'Harra

The residues resulting from the retort distillation of zinc ores have from 40 to 75 per cent of the weight of the original ore and contain from 5 to 15 per cent zinc . A rough estimate indicates that approximately 450,000 tons of residues are produced annually in the United States , containing about 36,000 tons of zinc . Besides the current production of residues there are at many smelter sites large accumulations from past operations which are available for treatment if this can be done profitably . In addition to their zinc content the residues contain much unconsumed coal , which has been carbonized during the distillation process , and those from most western ores also contain lead and silver . In this paper is summarized the information obtained in a survey , recently made by the Bureau of Mines , in cooperation with the Missouri School of Mines and Metallurgy , of processes which are in use or which have been suggested for the treatment of retort residues . The complete report of the survey is to be published as a Technical Paper of the Bureau of Mines .

Apr 1, 1923

By D. Bienstock

The use of alkalized alumina in removing sulfur dioxide from a coal-combustion flue gas at 625° F was investigated on a pilot plant scale. The absorber was 26 feet long and 1.6 inches ED. Counter-current gas-solids flow at gas velocities of 8 to 15 ft/sec in the presence and absence of baffles, as well as solids entrainment at gas velocities of 20 to 23 ft/sec with solids recycle, were employed. The spent absorbent as regenerated as fixed bed with the reducing gases--reformed natural .7.7d hydrogen. Of absorption-regeneration were successful completed using the alkalized alumina rolled into spherical granules 10 to 16 mesh. There was no loss in activity of absorbent toward SO2 with a modest attrition equivalent to 0.l percent of the solids feed. Supporting studies were conducted on the effect of the sodium content in the absorbent, the composition of the reducing gas, thermal treatment to increase absorbent hardness, and removal of absorbed chlorine from the absorbent. A mathematical model was formulated to describe the removal of SO2 by alkalized aluminum from fixed and falling beds.

Jan 1, 1967

By Stephen P. Holt

During the spring and summer of 1946, the Bureau of Mines put down 8 churn-drill holes and 9 diamond-drill holes, totaling 3,535 feet of bore, at the Blewett zinc-lead deposit in Jo Daviess County, Ill. Attention of the Bureau of Mines was first directed to this deposit by the Illinois State Geological Survey, which had investigated the Blewett mine. In the opinion of the Survey and the Bureau of Mines, the record of production and results of drilling previously done on the property were considered sufficient justification for continuing investigation to the north and south along a projection of the trend. This report describes the work done by the Bureau on this, property and presents the data obtained.

Jan 1, 1948

By Noel N. Moebs

The Bureau of Mines studied the feasibility of water diversion and overburden dewatering for underground coal mines in the Appalachian region. All relevant published literature pertaining to the occurrence and control of surface and ground water in underground coal mines was reviewed, and the impacts of mine water with respect to health and safety, production, environment, and costs were assessed and are described in this report. The report also identifies the sources of water inflow into underground coal mines, and gives a summary description and evaluation of techniques that can be used to reduce the amount of water entering these mines. Engineering practices currently used by operating coal mines in the Appalachian region to prevent the movement of ground and surface water into active coal workings were reviewed and are summarized. Major emphasis has been placed on the identification of geologic and hydrologic conditions of the site, the water control methods used, and an evaluation of their technical and cost effectiveness.

Jan 1, 1985

By Robert E. Manning

The Federal Coal Mine Health and Safety Act of 1969 has placed stringent limitations on the noise levels in which employees may work. This act can result in both increased labor costs because of noise-exposure time limitations and in high capital costs for modification of present equipment, and the design of new equipment, to comply with the law. The development of new noise-control systems is thus of immediate interest to industry. A current Research program at U. S. Steel is aimed at developing methods of controlling both the exhaust-air noise and the mechanical noise of a Stoper drill, a pneumatic percussive tool used for roof-bolting purposes in coal mines which has an approximate air consumption of 100 cubic feet per minute. This program is being performed under a contract between USS Engineers and Consultants, Inc. and the Pittsburgh Mining and Safety Research Center of the U. S. Bureau of Mines. In previous work at U. S. Steel, kidney-shaped mufflers were designed that wrap around the air leg of the drill for control of the exhaust noise. These mufflers were designed with the aid of a digital computer program that predicts the acoustic performance of mufflers.

Jan 1, 1975

By John R. McWilliams

This is one of a series of reports being published by the Bureau of Mines on mining methods and costs at various mines throughout the United States. Including the Holden mine in this series is particularly appropriate at this time. The mine was operated on a low-cost, large-scale production basis to compensate for low-grade ore. Even with the best conditions and the most efficient methods, the margin of profit was small. Under the present situation of rising costs and lowering metal prices, the profit margin vanished. On June 28, 1957, the mine operations ceased; therefore, this report can review the entire life span of the mine.

Jan 1, 1958