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By V. F. Parry

[Approximately 7-1/2 million tons of subbituminous coals are mined annually in Colorado, Wyoming, and Montana, of which 50 percent probably reaches domestic consumers. The moisture of these subbituminous coals is high, averaging about 25 percent when they are mined. The coals are non-caking end stack to a variable degree when exposed to normal atmospheric conditions. They are good domestic fuels, are considered to be smokeless in most furnaces, and have been used for many years in hand-fired domestic furnaces in which the practice is to employ large lutes for efficient combustion.]

Jan 1, 1941

By Jr. East

The Bureau of Mines conducted an investigation of the Nightingale tungsten deposit about 38 miles north of Fernley, Nev., from September 1939 to March 1940, to determine possible resources of tungsten ore. The property was owned by the Gold, Silver & Tungsten, Inc., which maintained its offices in Boulder, Colo. Ore was discovered in 1917, and some ore was mined in 1918 and treated in a mill at Toulon, a station on the Southern Pacific Railroad, 40 miles east. Same shipments were made since 1918, but no production figures are available. The ore is mined from nearly vertical tactite bodies at the limestone-granite contact. The Bureau of Mines excavated 944 linear feet of trenches, drifted 52 linear feet, sunk a shaft 20 feet in depth, sampled the underground workings by cutting 743 linear feet of channels, sampled the surface trenches by cutting 415 linear feet of channels, and drilled 9 diamond-drill holes, totaling 3,000 feet. The ensuing sections note the location and physical features of the district and specify the property and ownership. The history of the mine is briefed, and the geology and mine workings are described. The work done by the Bureau of Mines is summarized and supplemented in detail by assay maps, logs of diamond-drill holes in appendix A, and a table of sample analyses in appendix B.

Jan 1, 1950

By T. C. Wesson

The need for elemental-analysis information on coal mine dust for use in health and safety research prompted this study by the Bureau of Mines. Neutron-activation and X-ray fluorescent techniques were used to obtain five-element analysis (silicon, aluminum, iron, calcium, and magnesium) on 444 samples from 68 coal mines in 10 States. From these analyses, the average composition of the dust in coal mines was determined. The contribution of the primary dusting material (limestone dust) to the makeup of coal mines was shown. Regional differences in mine-dust composition were indicated.

Jan 1, 1974

By Robert S. Sanford

In April 1948, the Bureau of Mines was requested to evaluate the graphite deposit' known as the Benjamin Franklin and Just mines in Chester County, Pa. After preliminary investigation, it was recommended that the Bureau core-drill, trench, and sample the deposit and make beneficiation tests on the ore. During the first and second World Wars, flake graphite was in short supply, and a number of deposits in the United States were exploited. In 1942, the Defense Plant Corporation, through its lessee, the Benjamin Franklin Graphite Co., purchased 70.263 acres of graphite-bearing land and built a complete mining and milling plant with a capacity of 300 tons of crude ore per 24-hour day at a cost of $426,250 (Plancor No. 1254).

Jan 1, 1949

By W. Hodge Caraway

This report presents the results of an evaluation of several indirect methods of measuring the water content of oil-reservoir rocks. The water content of oil-base cores is considered to be most nearly representative of the water content of the undisturbed petroleum reservoir and therefore, the direct method of measuring the volumes of water in cores cut in oil-base drilling fluid was adopted as a standard for comparison. The indirect methods evaluated included (1) displacement through a semipermeable membrane by air, (2) centrifuge, (3) evaporation, (4) mercury injection, (5) chloride dilution and (6) electric logs. Approximately 270 samples of cores from petroleum-reservoir rocks were used in the study. The cores, most of which were cut with oil-base mud in the hole, were taken from oilfields in California, Texas Gulf coast, Colorado, Oklahoma, and Alaska.

Jan 1, 1959

By S. H. Ash

[On December 2, 1932, the Governor of California called upon the representatives of the mining industry of the State to attend a meeting at Sacramento to discuss ways and means of assisting is relieving some of its perplexing and extremely distressing problems, particularly the mounting cost of accidents which faces the industry with an industrial insurance rate for classification of $11.85 per $100 of pay roll, effective January 1, 1033. The significance of this fact is at once apparent when it is realized that the classification rates per $100 of pay roll for mining have steadily increased for some time, as follows: $3.91 in 1924, $5.54 in 1925 and 1926, $8.04 in 1927, $8.53 in 1928, $9.05 in 1929, $9.42 in 1930, $10.54 in 1931, $10.99 in 1952, and $11.85 in 1133. In other words, the cost rates have acre than doubled, wile statistics indicate that the accident rates nave shown an entirely different trend. At the meeting mentioned, one of the management officials sounded an effective keynote when he declared that a spade should be called: a spade. The perplexing problems of any industry can be approached best and remedies applied if that policy is kept to the front. It is appropriate to mention that high accident rates and a decrease in wages in recent years have unquestionably accounted in part for a unit cost rate, on a pay-roll basis; it also is well to explain that the policy years3 1926 to 1930, inclusive, are the years on which the accident-cost experience for 193: is based. That accident rates :lave not undergone the expected beneficial chance in California's experience is apparent in the words of a Bureau of Mines report:4]

Jan 1, 1933

By Phillip N. Yasnowsky

"In this Bureau of Mines report, the Federal income tax treatment of mineral exploration and development expenditures is summarized, and changes in the tax treatment of these expenditures since 1951 are detailed and analyzed. Although no attempt is made to establish causal relationships, major tax changes favorable to exploration and development activities did occur in 1951 and 1966 when the Nation was engaged in military actions and the economy was expanding. More recent changes have been unfavorable to exploration and development and were parts of major tax reform efforts. INTRODUCTIONThis Bureau of Mines report discusses the Federal tax law provisions relating to mineral exploration and development expenditures. These provisions, contained mainly in sections 616 and 617 of the Internal Revenue Code of 1954 (Title 26 of the U.S. Code), apply specifically to minerals (other than oil and gas), and thus are of interest to the Bureau of Mines.Bureau of Mines involvement in this subject stems from the legislative mandate in the 1913 amendments to the Organic Act of 1910 (the Act creating the Bureau) to conduct economic investigations of the mineral industries. Congressional concern with the financial conditions in the economic and mineral industries was expressed more recently in the Mining and Minerals Policy Act of 1970 and in the National Materials and Minerals Policy, Research, and Development Act of 1980. The General Accounting Office recommended in 1976 that the Department of the Interior ""identify and evaluate laws and agency programs that affect maintaining and developing a sound and stable domestic mining and minerals industry"" (17, p. iii). 2Taxes, a source of revenue to governments, are a cost to private firms. Thus, taxes directly affect private sector profits, and unique tax provisions are designed to encourage (or discourage) activities such as agriculture, construction, or mining. Even the international competitiveness of the domestic mineral industries may be affected by taxes because many minerals are traded in world markets."

Jan 1, 1985

By J. S. Gomer

The U.S. Bureau of Mines conducted Cu exchange tests for six common clays under simulated in situ leaching conditions. Regression equations were obtained from the data expressing the Cu exchange capacity as a function of Cu concentration, pH, and temperature. Using these equations, an analysis was made of the impact each clay could have on overall Cu recovery. The results suggest that Ca and Na montmorillonite clays could have a major impact on Cu recovery and that attapulgite and illite clays could have a smaller, but still significant, impact. Kaolinite and ripidolite clays pose little threat to loss of Cu from in situ leaching solutions.

Jan 1, 2010

By W. H. Young

The thickness of the coal seam is one of the more important items influencing the productivity and general overall efficiency of operation 1 of a coal mine. The average thickness of coal seams mined in the United States decreased 2 inches between 1950 and 1955 to an average of 62 inches, which also is 3 inches less than the 65 inches in 1945. The decrease in thickness is due partly to the increased production from strip mines with thinner seams and partly to the increased percentage of total production at underground mines in certain States having thinner seams. The thickness of seams at auger mines was measured for the first time in 1955 and was 53 inches. Though bituminous coal and lignite is mined today from seams of exceedingly variable thickness -less than 2 feet to ore than 50 feet -a large majority of the production, 65 percent in 1955, came from seams 3 to 6 feet thick. This is not surprising since the coal seam of moderate thickness presents the least mining difficulties.

Jan 1, 1957

By Jack O. Jones

The Furnish mine, Caharrus County, W. C., was operated intermittently until 1905 as a gold mine. Scheelite was discovered by A. L. Mash in the mine dumps of the Furniss and Phoenix mines, and he later informed the Bureau of Mines of his discovery. The Bureau of Mines, in two projects at the deposit in 1948 and in drilled 12 holes totaling 1,706.6 feet, examined and sampled the underground workings, excavated by bulldozer and hand, 3,155 linear feet of trenches and collected numerous samples for assay. The best scheelite shown; was found in the underground exposure of the Furniss mine.

Jan 1, 1950

By Richard N. Spencer

This report describes investigations of the economic merits of multiple zone mining and beneficiation versus selective mining of altered Western phosphate rock. The same deposit was considered in both instances and it was assumed that the grade of selectively mined ore was comparable to the grade of the concentrate from beneficiation. The beneficiating scheme used for the investigation was one proved by small continuous circuit operation. All economic factors were found to favor multiple zone mining plus beneficiation. Capital requirements and production costs were lower, and production life of the deposit was extended 4.5 times. The concentrate from beneficiation would be a uniform high-quality feed for acidulation and would be low in stable metallic oxide (R203) content. Such a feed would permit improved plant operating control, and the low R203 would promote more rapid filtration and minimize sludge formation in the phosphoric acid. With the proposed treatment, the concentrate produced by flotation from this deposit would cost about 1.5 times as much per ton as the concentrate produced by classification sizing. Therefore, inclusion of a flotation step in treatment schemes requires an economic analysis for each ore deposit.

Jan 1, 1971

By B. J. Moore

This publication contains routine analyses and related source data for 374 natural gas samples from 24 States and 5 foreign countries. These samples were collected during calendar year 1966 as a part of a continuous survey of the free world for occurrences of helium in natural gas. This survey has been conducted in the United States by the Bureau of Mines since 1917. In late 1965, the survey was expanded to include foreign gasfields. The analyses of foreign samples contained in this publication represent the first samples received as a result of this expanded program. The analyses published herein were made by mass spectrometer and a special helium analysis apparatus, which are described in Bureau of Mines Bulletins 4863 and 576.4 Eight previous publications have been made to present the results of 7,244 gas analyses made? by the Bureau of Mines Helium Activity prior to 1966. The first three, Bulletins 486,5 576,6 and 617,7 contain analyses and related

Jan 1, 1967

By Roswell W. Prouty

As part of a general plan for control and economic utilization of the waters of the Missouri River Basin as well as development of its inherent power resources, the Corps of Engineers of the United States Army has under construction a rolled earth dam near the site of old Fort Randall in South Dakota. The dam is in Charles Mix and Gregory Counties on the Missouri River at a point about 922 miles above its mouth. It is approximately 125 air-line miles southeast of Pierre and 55 miles southwest of Mitchell, S. Dak. The storage reservoir to be formed by the dam will extend upstream for 150 miles and, at maximum operating pool level, will cover an area of some 107,000 acres. It will have a storage capacity of 6.2 million acre feat.

Jun 1, 1949

By Donald F. Reed

In the latter half of 1948 the Bureau of Mines investigated the Magnet Cove Rutile Co.'s prerty in northern Hot Spring County, Ark. This work was supplemental to the work done by the Bureau on the same property in 1945.2/ It was undertaken for the purpose of investigating the extent of the ore body toward the south and west and at depth and to obtain representative samples of the ore for metallurgical tests. For the latter purpose, the samples were so taken as to minimize alteration of the physical characteristics of the ore, these characteristics being determining factors in working out processes of bencficiation. During the investigation, 27 holes were drilled, 10 with a diamond-coro drill end 17 with churn-drill rigs using a Baker standard cable-tool core barrel. Drilling developed an extension of the ore deposit westward from the previously mined area but did not disclose the full depth of mineralization. Metallurgical tests to determine methods of beneficiating the ore and utilizing the resultant products are now in progress.

Dec 1, 1949

By Nar S. Dala1, Xianglin Shi, Val Vallyathan

"Electron spin resonance (ESRJ and cytotoxicity measurements were made on newly fractured silica to examine specifically the role of the fracture-induced, silicon-based radicals (Si· and SiO·) and silica-generated hydroxyl (·OH) radicals in the mechanism of the cell membrane damage by silica. The concentration of the Si· and SiO · radicals was controlled through decay processes, thermal annealing, and boiling, while that of the ·OH radicals was varied by using catalase, superoxide dismutase, KMnO, Na;iSeO:y ascorbic acid, and metal ions, and monitored via ESR spectroscopy. The dust's cytotoxicity potential was evaluated by measuring the silica-induced hemolysis and also by determining lipid peroxidation (using linoleic acid). From the comparison of hemolysis and ESR results it is deduced that the radicals play little or no role in the silica-induced hemolysis. However, the lipid peroxidation data indicate that the radicals might be involved in the initiation of an oxidative chain reaction leading to the macrophage membrane damage through lipid peroxidation. INTRODUCTIONThe biochemical mechanism of quartz-related pneumoconiosis is still not fully understood. It is believed, nevertheless, that one event of primary importance is the perturbation of cell membranes by the dust particles (Allison et al., 1966; Allison and Harrow, 1971; Bateman et al., 1982; Parazzi et al., 1968; Reiser and Last, 1979; Shi et al., 1989; Summerton et al., 1977). The ensuing cell: membrane damage unleashes certain lytic enzymes resulting in additional cell injury and eventual fibrosis (Nolan et al., 1981; Summerton et al., 1977). Thus considerable effort is currently being made toward the understanding of the processes by which quartz particles disrupt the membrane of a red blood cell (RBC) or a pulmonary alveolar macrophage (PAM). A simple but important method of evaluating the membrane damage potential of a dust is the hemolysis test (Harington et al., 1971). Even though this test is used routinely for screening dusts for their cytotoxicity potential, the biochemical mechanisms underlying the cell lysis by many dusts, including quartz, is still controversial (Kilroe-Smith, 1974; Singh and Rahman, 1987), and this provided us the impetus for the present undertaking."

Jan 1, 1990

The Bureau of Mines performed cratering experiments in a homogeneous granite to test scaling laws for charge weights of 0.00476, 0.0220, 0.0900, 0.304, and 1.03 lb. Agreement among the data was best when empirical scaling exponents greater than one-third were assumed. Although the analysis showed that the best empirical scaling exponents were 0.37 for crater volume, 0.38 for crater radius, and 0.39 scaling for crater depth, all three crater dimensions could be scaled with a 0.38 scaling exponent.

Jan 1, 1970

By Chas. F. Jackson

The annual reports of the supervising engineering of the nine sections comprising the Mining Division are assembled in the following pages and constitute the annual report of the division. In planning activities, the aim is to adapt them to changes in conditions, in the needs of the mining industries, and in the public interest; those current activities that contribute most to problems of present concern are emphasized, investigations of less immediate importance being recessed, if necessary.

Jan 1, 1940

By Chas. F. Jackson

The annual reports of the supervising engineers of the nine sections comprising the Mining Division are assembled in tie following pages and constitute the annual report of the division. In planning activities, the aim is to adapt them to changes in conditions, in the needs of the mining industries, and in the public interest; those current activities that contribute most to problem of present concern are emphasized, investigations of less immediate importance being recessed, if necessary.

Jan 1, 1940

By G. W. Jones

In cooperation with the Edison Electric Illuminating Co. of Boston, Mass., and the Boston Consolidated Gas Co., a survey has been conducted continuously since 1929 by the Bureau of Mines to determine the general hazards of combustible gases and vapors in manholes of the Edison Electric Illuminating Co. The New England Telephone & Telegraph Co. also has cooperated in the investigation, and tests have been made in its manholes since May 1, 1933. Yearly reports6/ on the results obtained since the beginning of the survey have been published. The method and procedure of conducting the survey in 1936 were the same as heretofore.

Jan 1, 1938

By George A. Morgan

The production and processing of crude petroleum and natural gas are the dominant economic sectors of the Middle East. Development of downstream petrochemical and fertilizer industries continues as a major investment area. In 1993, the 15 countries that constituted the region accounted for 29 % of world crude petroleum output, 19 % of world natural gas plant liquid production, and 6 % of world dry natural gas production. Only Cyprus and Lebanon were not crude petroleum producers. Regional output was up for most major mineral commodities. A major exception was phosphate rock, which declined sharply owing to reduced worldwide demand. Total crude petroleum output declined by over 100 Mbbls, again owing to slack demand in the major industrial countries.

Jan 1, 1995