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By W. W. Adams

The year 1937 was signalized by increased employment in the metal-and nonmetal-mining 4 industry of the United States. Measured by the number of men working, there was a 17-percent gain in employment compared with 1936. In total number of man-hours worked at all mines, the gain was slightly over 18 percent. Hazards connected with mining resulted in more accidents to the workers than in 1936, but the increase in number of accidents caused only a slight rise in the accident rate because of the much larger increase in the number of man-hours worked. In fact, the fatality rate per million man-hours of exposure was lower in 1937 than in 1936, but the rate for nonfatal injuries increased slightly.

Jan 1, 1940

By Sidney Katell

This study estimates capital investment, operating costs, and selling prices for four underground bituminous mines producing coal with annual production ranging from 1.06 to 4.99 million tons. It is assumed that the mines have a 20-year life. Wages and union welfare payments are considered as of November 12, 1973, under the Bituminous Wage Agreement of 1971, and costs for material and equipment are based on 1973 indexes. Initial capital investment ranges from $12,540,700 for the 1.06-million-ton-per-year (MM tpy) mine to $44,720,500 for the 4.99 MM tpy mine. Total capital investment ranges from $21,850,700 to $75,693,500 for the same mines. Corresponding selling prices for the coal range from $8.76 to $7.53 per ton, assuming a 12-percent discounted cash flow rate of return after Federal income taxes.

Jan 1, 1974

By James S. Browning

The Bureau of Mines conducted laboratory batch and small-scale continuous flotation tests of weathered mica pegmatite ores from Alabama and North Carolina to determine the technical feasibility of recovering commercial-grade mica concentrates. A new anionic-catonic method was developed for recovering mica in the presence of clay slimes. In continuous tests, concentrates containing 98.1 percent mica were obtained from the Alabama pegmatite ore; the North Carolina pegmatite ore concentrates contained 97.2 percent mica. The recoveries were 83.8 and 81.6 percent, respectively.

Jan 1, 1965

By A. M. Evans

Because of an urgent national need for manganese, the deposits in the Little Florida Mountains of Lune County N. Mex., were visited by O.H. Metzger, an engineer of the Bureau of Mines, on June 12 and 13, 1940, accompanied on the second day by S. G. Lasky, a geologist of the Federal Geological Survey. After this preliminary examination, it was recommended that exploratory work be done by the Bureau of Mines on several properties in the district. An exploratory project of trenching, sampling, and core drilling was started by the Bureau of Mines in September 1940 and completed in May 1941.2/ Work was done on three properties - the Luna mine, the American group of claims, and the Manganese Valley mine. The Little Florida manganese district is situated on the eastern slope of the Little Florida Mountains about 2 miles south of U. S. Highway 80-90, 12 to 14 miles southeast of Deming, Luna County, N. Mex. The principal claims comprise the Luna Manganese, American, and Manganese Valley groups.

Jan 1, 1949

By James J. Dowd

The investigation to evaluate the reserves of coking coal is being made by the Bureau of Mines in three parts: (1) To estimate known measured and indicated recoverable reserves of all coking coal; (2) to upgrade marginal coals through effective preparation; and (3) to study the carbonizing properties of coal and coal blends not now widely used for metallurgical coke making. This is the tenth of a series of reports giving the results of studies by counties under part (1) of the investigation. (See appendix.) This report covers Knott County, Ky., which comprises parts of the Salyersville, Prestonsburg, Troublesome, Hindman, Pikeville, Cornettsville, and Whitesburg quadrangles. (See fig. 1.) A base map for each bed in each quadrangle was made to the scale 1 inch equals 1,200 feet. Maps of mines, locations of drill holes, bed and total coal thicknesses, and the outcrop of the bed were plotted on the maps. With all available data plotted, isopach lines were drawn to limit areas of known unmined reserves in beds up to 14 inches thick, 14 to 28 inches thick, 28 to 42 inches thick, and over 42 inches thick. These areas of coal reserves also were divided into "measured" and "indicated" categories. All areas in each thickness range and category, mined-out areas, areas excluded from the estimate but which may contain reserves based only on geologic inference, and areas outside of the outcrop were measured by planimeter on the base maps. Estimates of total reserves 14 inches and more thick and maps for individual beds were prepared from these data.

Jan 1, 1952

By Corate L. Brierley

Low-grade porphyry copper ores containing chalcopyrite as the primary mineral was leached by two strains of acidophilic, thermophilic microbes belonging to the genus Sulfolobus. Leach tests were conducted in glass columns heated to 60-70° C. Pinto Valley and San Manuel ores sized to -1/2 inch + 50 mesh were effectively leached by the thermophilic organisms, but pinto Valley and Cyprus Bagdad ores sized to -2 inch + 1/2 inch resisted leaching. Aeration did not contribute measurably to bacterial copper extraction, since two columns, one inoculated and one sterilized, having a rest/ leach cycle without recurrent aeration exhibited copper extraction patterns similar to those of the aerated columns. Distilled water can be substituted for 9K medium without diminishing copper extraction. Decreasing the pH of the leachate to about 1.8 enhanced the extraction of copper from pinto Valley ore with the thermophilic microbes. Thiobacillus ferrooxidans was found to be relatively ineffective at copper extraction from pinto Valley ore. Of eleven solvent extraction reagents tested, Adogen 364 and Warsol at concentrations of 0.1% and 0.012 were inhibitory to oxygen uptake by the two Sulfolobus strains. Di-2-ethyhexyl phosphoric acid at concentrations of 0.1%, 0.01% and 0.001% were totally inhibitory to the respiration of both organisms.

Jan 1, 1979

By F. E. Griffith, C. H. SEELING

Cardox blasting is used widely in coal mines in the United States . A model of a Cardox blasting device was approved by the Bureau of Mines subject to certain conditions and limitations , and the approval was extended to other models from time to time . Certain special hazards are entailed in the use of Cardox as with explosives . One of these is flying shells . In some blasts , the Cardox shell is violently ejected from the borehole and flies like a projectile , frequently ricocheting off solid objects and striking points considerably off the line of its initial flight . Flying shells have been known to pierce the webs of structural - steel beams , to pass through both sides of allsteel mine cars , to be driven through stout hardwood timbers , to knock out timber sets , to damage loading equipment , and to break or short - circuit power lines . A considerable number of shot - firers and other workers have been struck by flying shells and killed or injured . Accidents from this cause , although not as frequent as other types of mine accidents , are usually serious , closely approximating accidents caused by blasting with ordinary explosives . The increasing number of such accidents prompted a Bureau of Mines field investigation of possible methods of preventing dangerously violent ejections of Cardox devices . This report contains pertinent data collected during the investigation and describes methods tested and discarded as well as the development and proof of an apparently satisfactory method .

Jun 1, 1943

By H. B. Humphrey, F. E. Cash

From 1900 to 1929 , 1,005 or approximately 30 per cent of all fatalities in the coal mines of Alabama were caused by fires or explosions of gas and dust . In the 3 -year period from 1927 to 1929 only 15 men were killed by these causes , a reduction from 30 to 9 per cent of the total . Notwithstanding this marked improvement , which is due largely to the efforts made by the State inspection department , the operators , and the Bureau of Mines to stamp out this type of disaster , Alabama still has more than its share of such fatalities which can and should be prevented. A list of explosions from 1894 to 1929 compiled from information obtained through the records of the State Inspector's office , the reports of Engineers of the Bureau of Mines , and the operators , is given in Table

Oct 1, 1930

By K. E. Tame

The Bureau of Mines is studying possible modifications in conventional uranium ore-processing steps to confine and permit controlled disposal of radioactive wastes. Surveys of Ra226 contamination of liquid wastes from uranium mills indicated that the Vanadium Corporation of America plant at Durango, Colo., had one of the more urgent problems. A possible procedure for minimizing the waste disposal problem was to reuse the waste solution in the mill--in effect, erasing the need for disposal of liquid waste. In examining this possibility, interlocked bench-scale leaching and solvent extraction tests simulating the Durango flowsheet were made. The simulated reuse of barren raffinate for leaching and washing was carried through three separate campaigns of 9, 12, and 35 cycles each.

Jan 1, 1961

By C. E. Arthur

The Bureau of Mines has investigated the problem of radioactive contamination using nuclear explosives to fracture petroleum reservoirs in an attempt to stimulate production. It was concluded that some contamination of petroleum products will almost certainly occur. However) the degree of contamination cannot be predicted except by a full-scale experiment) since simulating the problem in the laboratory is economically impossible because of the extremely high temperatures and pressures that must be reached in extremely short time intervals if a reasonable analog is to result.

Jan 1, 1965

By R. V. Ramani, R. A. Jankowski, R. Bhaskar

"The spatial distribution of airborne dusts, deposition of dust in the airway, as well as the effect of airflow velocity and particle density on dust behavior in mine airways were studied in a set of experiments performed in a mine airway under controlled conditions. Considerable deposition of dust near the source was indicated. Pronounced effects due to velocity were observed in ambient dust concentration and deposition along the mine airway, both in the respirable and the total size ranges. Cross-sectional concentration measurements indicate an increase in concentration from the roof to the floor. The average cross-sectional concentration is about 75% of the concentration in the center of the airway.IntroductionA number of studies have been performed since the early 1950s on the behavior of dust in mine air (Bradshaw and Godbert, 1954; Dawes and Slack, 1954; Bradshaw et al., 1954; Hall, 1955-56; Reinhardt, 1971; Ford, 1971; Courtney et al., 1982). While the experimental data available from these studies are indeed useful in understanding dust cloud behavior in a specific situation, no generalized conclusions can be drawn because of the lack of data on parameters such as flow velocity, size distribution of the source dust, and particle density. These change from mine to mine or even within the same mine. The present study is aimed at providing a better understanding of the temporal and spatial behavior of dust particles in underground' mine airways (National Academy of Sciences, 1980). The characteristics studied encompassed airborne concentrations and floor depositions over the entire size range as well as the respirable size range. The experimental results in this paper are intended to complement a mathematical model developed to predict ambient concentration and deposition of airborne dust in mine airways (Bhaskar and Ramani, 1986)."

Aug 31, 1989

By Raymond M. Stateham

A portable, handheld infrared scanner has been used to detect abnormal surface temperature on dumps of flood-generated trash near Wilkes-Barre, Pa. Three of eight dumps examined had thermal anomalies on the surface, indicating temperature buildup at depth. The anomalies found with the scanner were verified by measurements with a thermocouple probe or a carbon monoxide detector. One week after the investigation was completed, open fire broke out at the site of one of these thermal anomalies; about 6 weeks after the investigation, a thermal anomaly in another dump was verified when a trench was excavated in the dump.

Jan 1, 1973

Major activities of the Bureau of Mines Explosives Research Center during fiscal year 1965 (July 1, 1964, to June 30, 1965) are reviewed briefly. Part 1 summarizes significant accomplishments of the projects that were active during the report period. Part 2 presents short abstracts of the publications that appeared in the Bureau series and in other media during fiscal year 1965. Publications issued after June 30, 1965 are noted where pertinent in footnotes but are not abstracted.

Jan 1, 1966

By Clayton M. Rumsey

The U.S. Bureau of Mines investigated prospects and mineralized areas in and adjacent to the Indian Pass and Picacho Peak study areas in 1983 and 1984. The Indian Pass study area contains 33,640 acres and the Picacho Peak study area contains 5,450 acres. The study areas are located in the southeast corner of California and are underlain by Precambrian gneiss, Pre-Tertiary metavolcanic and metasedimentary rocks, and Tertiary volcanic and non-marine clastic rocks. Low-grade gold-silver resources may be present in hydrothermally altered gneiss in the upper plate and altered schist in the lower plate of the Chocolate Mountain thrust fault. The thrust fault is exposed in the study areas for about 3.5 miles west and 5 miles east of Indian Pass. Mineralized zones in the thrust plates were not discovered until 1983. Earlier prospecting explored areas containing minor copper carbonate occurrences in schist and sedimentary and volcanic rocks that are younger than the thrust. Twenty-three mines, prospects, and mineral occurrences inside the study areas and fourteen outs; de were examined for this study. These surficial copper occurrences have been prospected extensively in the study areas; large areas have been scraped, pitted, and trenched by bulldozers. However, they appear to be of limited economic significance. Slightly mineralized zones are in the northwest part of the Indian Pass study area where granite contacts sedimentary and volcanic rocks.

Jan 1, 1986

By Robert W. Freedman

Vacutainers are used by the Bureau of Mines and the Mining Enforcement and Safety Administration (MESA) for sampling mine air and products of combustion. Tests were conducted on both 10-ml and 30-ml sizes to study shelf life stability during storage, pretreatment of stoppers, and handling of a wider range of compounds. A chamber was constructed to provide convenient, efficient evacuation of the Vacutainers shortly prior to use. Fixed gases and C1 ?C5 hydrocarbons could be stored for 1 week or more after sampling. Where decreases occurred (C02 and C3-C5 hydrocarbons), they were predictable as a function of storage time. An unexplained phenomenon, slow accumulation of CO in evacuated Vacutainers, occurred after a few weeks of storage. The levels were low and time dependent. Attempts to eliminate this behavior by pretreating the stoppers were unsuccessful.

Jan 1, 1976

By R. E. Morgan

Two sizes of Pennsylvania anthracite were gasified in the new-type Lurgi pressure generator at the Dorsten, Germany, works of the Steinkohlengas, A. G. These tests demonstrated that Chestnut-size anthracite and a Rice-Buckwheat mixture containing 27 and 19 percent ash, respectively, could be gasified satisfactorily at an elevated pressure in a fixed bed with oxygen and steam. These coals were especially prepared to approximate a rough-cleaned coal and a washed and screened product. The operating data obtained from the two tests and materials requirements are summarized. A wide range of reactant ratios could not be tested, nor could optimum operating conditions be determined, as the generator was being used throughout the testing program, employing normal operating practices, to produce gas for the gas grid; and the most economical coal, steam, and oxygen ratios may not have been used. Comparative costs are presented of the raw materials required for producing a high-B.t.u. gas, based on the operational data obtained from these tests and, to some extent, on data extrapolated from laboratory experimentation. A flowsheet of a proposed process for producing a high-B.t.u. gas by Lurgi gasification, followed by methanation, is also included.

Jan 1, 1958

By L. A. Johnson

The Bureau of Mines analyzed three cores from the south Seep Ridge area of the P. R. Spring tar sand deposit of northeastern Utah. Four tar sand zones are indicated in the area. The zones range in average thickness from 13 to 24 ft. The total net thickness of the tar sand in the three coreholes ranges from 71 to 112 ft. The tar sand occurs between the depths of 27 and 254 ft. It has good porosity, 25.6 pct of bulk volume; high permeability before and after oil extraction, 819 and 2,218 md, respectively; but a relatively low oil saturation, 36.5 pct of pore volume. Gravity of the oil ranges from 8.20 to 16.5° API.

Jan 1, 1975

By J. F. Barkley

The following questions and answers were prepared principally to supply information in answer to general inquiries received by the Bureau from those contemplating the use of propane and butane fuels . Primary or basic information only is covered; this usually gives enough guidance for most inquirers . To those who wish information of the treatise type , the handbook , Butane- Propane Gases , published by the Jenkins Publications , Inc. , 1709 West 8th Street , Los Angeles 14, Calif . , is suggested .

May 1, 1949

By F. M. Goodwin, John Campbell, W. P. Yant, G. W. Jones

"INTRODUCTION The cooperative investigation dealing with the general hazards of combustible gases and vapors in manholes owned by the Edison Electric Illuminating Co. and the New England Telephone and Telegraph Co. in Boston, Mass. and surrounding territory, was continued during 1934.The method and procedure of conducting the survey for 1934 were the same as those followed heretofore.ACKNOWLEDGMENTSThe cooperative investigation was arranged through the interest and effort of F. D. Comerford, president of the Edison Electric Illuminating Co. of Boston; E. M. Farnesworth, Jr., vice president and general manager of the Boston Consolidated Gas Co.; and A. C. Fieldner, chief engineer, Experiment Stations Division, U.S. Bureau of Mines. Thomas H. Haines, superintendent, Distribution Department, of the Edison Electric Illuminating Co., cooperated in furnishing both men and information for the work.The New England Telephone and Telegraph Co., through Chief Engineer G. K. Manson, R. F. Esterbrook, H. G. Crush, and A. J. McCarron, cooperated by assigning a telephone company employee for the test truck. The company has borne its proportionate share of the expense and has taken an active interest in the work during the year. The test crew was operated under the direct supervision of John Campbell, superintendent of the Special Service Department of the Edison Electric Illuminating Co., and 7. M. Goodwin, vice president of the Boston Consolidated Gas Co."

May 1, 1936

By Jack E. Fraley

In this Bureau of Mines study, sealants containing mineral wool, cement, etc, were sprayed through dry-process equipment that propels dry material pneumatically to the water-adding nozzle. Advantages over slurry applications include no mixing, no extensive cleanup, and freedom from hardened cement in equipment should power be lost. Sealants with large mineral wool nodules (>l-inch) were sprayable at rates to 900 square feet per hour for 1/2-inch thickness with little dust and smooth material flow through equipment, but they were weak for mine use, Materials containing small wool nodules (1/4-inch) were stronger but tended to plug lines because the nodules were inadequately separated in the shredder. Increasing the dedusting oil also increased line plugging by holding the nodules together in larger lumps. Best results were obtained using a 3/4-inch-nodule wool with cement binder, which provided both smooth flow through the machine and adequate strength.

Jan 1, 1977