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By G. D. Jermain

Exploration of the Antimony Peak district by the Bureau of Mines was conducted under the authority of the Strategic Minerals Act of 1939. Antimony was one of the seven metals designated at that time as strategic by the Secretaries of War, Navy, and Interior upon advice of the Army and Navy Munitions Board. As a result of many field examinations, the Antimony Peak property was chosen as one of the most attractive for the possible development of emergency antimony reserves. Exploration by the Bureau of Mines began in November 1940 and was concluded in May 1941.

Jan 1, 1949

By George L. Gates

The Bureau of Mines developed a rapid instrumental method of analyzing oil well scales containing primarily barium sulfate. After removal of oil and water by carbon disulfide) the scale was dissolved in strong hydrochloric acid. The cations, barium, calcium, strontium, magnesium, and iron, were determined with the flame photometer using the method of additions. Sulfate was deter-mined colorimetrically after separation by selective adsorption on an alumina column. Phosphate was determined colorimetrically and carbonate titrimetrically. The method was reasonably accurate, although iron and magnesium were found to have mutual interference.

Jan 1, 1965

By J. R. Thoenen, J. L. Vallely, M. C. Malamphy

"SUMMARYMagnetic and gravimetric surveys wore conducted over an area of ap¬proximately 1,400 square miles in the bauxite district of central Arkansas. The primary purpose of these surveys was to discover any possible buried and hitherto unknown syenite masses favorable for the occurrence of bauxite and to determine the approximate position of the buried flanks of the known syenite masses which might offer conditions favorable for the discovery of new ore bodies.Those surveys indicated that the various syenite outcrops were domes or bosses on a large batholith and that ether similar domes occurred on the batholith but did net outcrop.Drilling on the local geophysical anomalies proved the presence of 10 buried domes, but only 2 of them were found to project above the upper surface of the Midway clays, a requisite of conditions favorable for the occurrence of bauxite ore bodies. The geophysical data indicated the approximate configuration of the buried flanks of the known syenite coutcrops, and the portions of these flanks that project above the Midway have now been outlined more accurately by drilling.The geophysical surveys have produced evidence permitting the elimi¬nation of a large area as unfavorable for the occurrence of bauxite.Magnetic surveys extending along the Midway-Wilcox contact from Gurdon, in Clark County, on the southwest to Searcy, in White County, on the northwest have proved the improbability of the existence of other syenite masses similar to those found in Pulaski and Saline Counties. A detailed magnetic survey of the Magnet Cove area in Hot Spring County has proved that the syenite mass exposed in that locality is an isolated intrusion and entirely unrelated to those of Pulaski and Saline Counties. This syenite mass does not occur under conditions believed to be favorable for the occurrence of bauxite."

Feb 1, 1945

By W. H. Oppelt

A lignite from west-central North Dakota (Mercer County) was dried by the Bureau of Mines by the Fleissner process at saturated steam pressures to 1,500 pounds per square inch absolute (p.s.i.a.). Normally, the process is operated at pressures of 200 to 370 p.s.i.a. At the highest pressure the temperature of the saturated stearn is 596° F. The purpose of the investigation was to evaluate the influence of very high stearn pressure and temperature on moisture removal, steam consumption, and physical and chemical characteristics of the dried lignite. Two drying cycles were used: A normal cycle, corresponding to previously established standard time requirements, and an accelerated cycle, wherein time requirements were determined by boiler capacity and handling speed. Blank tests to determine stearn requirements for heating the empty autoclave were performed for each cycle and each test condition. Moisture removal, final moisture content, net steam consumption, and size stability of the dried lignite were determined.

Jan 1, 1959

By J. D. Warne

The ferberite district of Boulder County, Colo., has been an important producer of tungsten since 1900. During World War I, high prices for tungston concontrates resulted in a brief period of intense activity, and the production in 1917 was 2,707 tons of 60 percent W03 concentrates. Production declined thereafter, and in 19.2 the tungsten produced in Boulder County represented about 4 percent of the Nation's output, being exceeded only by the scheelite production in California, Nevada, and Idaho. Boulder County has boon an important source: of tungsten in the Korean emergency; the present report does not describe this recent activity, as it will be covered by a future publication. Tungsten occurs in small ore shoots of narrow and irregular veins. Most of the ore shoots have been found outcropping on the surface. Core drilling; has been used by the larger operators to explore for new veins and to locate extensions of known veins.

Jan 1, 1953

By Robert F. Chaiken, Thomas H. Dubaniewicz, Gregory M. Green, Kenneth L. Cashdollar

Optical technologies have progressed rapidly in the past 15 years. One application of laser technology in underground coal mines currently under evaluation is the remote measurement of explosive methane gas. Federal regulations require that atmospheric monitoring systems used in gassy underground mines where permissible equipment is required shall be intrinsically safe. Mine Safety and Health Administration criteria for the evaluation and testing of intrinsically safe apparatus and associated apparatus contain no specific guidance for optoelectronic components such as diode lasers. The National Institute for Occupational Safety and Health is conducting a study to help provide a scientific basis for developing appropriate safety guidelines for optical equipment in under- ground coal mines. Results of experiments involving ignition of methane-air mixtures by collections of small heated particles of Pittsburgh seam coal and black iron oxide are reported. The inert but more strongly absorbing iron oxide targets consistently ignited methane-air mixtures at lower powers than the coal targets. Minimum observed igniting powers for laser energy delivered by 200, 400 and 800 pm core fiber optic cables and directed onto iron oxide targets in methane-air atmospheres were 0.6, 1.1, and 2.2 W, respectively. Comparisons with the results of other researchers are made. A thermal layer theoretical approach to describing the process is included as an appendix.

By Oliver C. Ralston, and others

"INTRODUCTION Investigations of the Nonmetals Division are now conducted at College Park, Md.; Tuscaloosa. Ala.; Seattle, Wash.; and. Norris, Tenn. The last of these was acquired, this year by arrangement with the Tennessee Valley Authority and is engaged in electrothermel research, using power generated by the T.V.A. and. raw materials from that region. In general, the work of the division is concerned with dressing nonmetallic minerals end utilizing the products there-from. Coal, salts, and waters are investigated, and the suitability of apparatus and equipment is studied.As the Metallurgical. Division of the Bureau of Mines makes routine tests of certain nonmetallic ores under prescribed conditions for the public if they are of general interest, the published reports of that division should be read and thus, with the reports of tile Nonmetals Division, the whole field may be covered."

Oct 1, 1939

By Mohan K. Wali

Soil and vegetation development were studied on abandoned mine sites near Velva in Ward County, North Dakota. The sites studied were 1, 7, 17, 30 and 45 years old since abandonment; unmined sites were also studied to provide measures of comparison. Species diversity was the highest at unmined sites (114) and lowest at the I year old site (26); sites 7, 17,30 and 45 years old had 37, 52, 43 and 68 species, respectively. Stand ordination revealed that site ages were the most important in influencing species diversity and composition. Stand-environ-mental complex ordinations encompassing 53 variables showed topographic variables to be the most important followed by site ages. Rates of nutrient accumulations were as follows: organic carbon 13.1 g m-2 yr-1; nitrogen 2.5 g m-2 yr-1; phosphorus 0.01 g m-2 yr-1; potassium 0.49 g m-2 yr-1. Carbon-nitrogen ratios showed the widest range for 1 year old sites (5-40) but 70 percent of the 45 year old sites showed values below 15 which were com-parable to the unmined mixed grass prairie sites. Species distributional diagrams are provided to show their habitat preferences which may be helpful in formulating species prescriptions for revegetation.

Jan 1, 1982

By Young W. A.

The Eagle Silver mine is in the Rush Valley mining district, Tooele County, Utah, and is now operated by the Hampton Mining Co. The property, originally referred to as the Argent, is reported to have been one of the first discoveries in the district. The early operators mined ore to a depth of 850 feet, at which point the property was abandoned because of excessive water. During 1905 the Honerine tunnel was driven into the area approximately 1,800 feet below the collar of the Argent shaft. This tunnel served to drain the levels above and operations were resumed. Ore deposits in the Eagle Silver mine occur in the Galena King lime-stone, a 20-to 60-foot member of interbedded quartzite and limestone in the Oquirrh formation of Pennsylvanian age. This member has been faulted along the bedding, forming the Galena King gouge. Mineralization commonly occurs in or near this gouge area in a brecciated, highly altered, pipelike zone. The known ore shoots occur in association with the breccia pipe, commonly adjacent to cross faulting and porphyry intrusions. In general, two ore shoots have been mined on the upper levels of the mine, one lying to the east and the other to the west of the breccia zone. The Bureau of Mines diamond-drilling program was begun during the latter part of 1948 and completed early in 1949. Nine holes were drilled, aggregating 852.8 feet. Sludge and core samples from mineralized sections were analyzed in the Salt Lake City laboratories. A total of 87 sludge, 71 core, and 11 chip samples was submitted for analysis.

Jan 1, 1950

By G. Richards Gwinn

The mineral olivine, though known to mineralogists for many years, was of little commercial value in the United States before 1933. It was first described in 1790 by Johann Gottlieb Werner, who named it "olivine in allusion to its olive-green color. Commercial olivine first attracted attention because of its refractory properties. Further research has developed methods of extracting the magnesia content for the production of various magnesium compounds. Experimental and pilot-plant work also are in progress to make olivine available as a low-cost raw material for the production of magnesium metal.

Jan 1, 1943

By David D. Walker

The purpose of the investigation was to describe and appraise tungsten deposits in Montana . The work supplements previous investigations made by Pattee ( 10 ) and Walker ( 17 ) in selected areas of the State . Scheelite deposits in tactite are the most numerous and most important economically , having accounted for nearly all of the State's tungsten production . Of the 64 deposits examined during the current study , 50 contained scheelite , 11 hubnerite , 2 wolframite , and 1 ferberite . The State's major tungsten production has been from scheelite deposits in Beaverhead County . The report lists , by counties , the type and grade of each deposit . The more important occurrences are accompanied by geological and assay maps .

Jan 1, 1963

By K. A. Johnson, H. F. Yancey

"INTRODUCTION Coals vary so widely in their burning characteristics that all coals prepared for domestic stoker use cannot be burned efficiently on every type of stoker. The overfeed stoker, a large number of which are in use in the Pacific Northwest, operates satisfactorily when burning low- to high-ash, noncaking bituminous or subbituminous coals, whereas on the clinkering-type, underfeed, bituminous stoker both caking and noncaking bituminous and subbituminous coals are burned, generally with ash contents below 12 percent and ash-softening temperatures between 1,800º and about 2,600º F. Because fly ash continues to be one of the most troublesome factors in domestic underfeed stokers, noncaking coals especially must be chosen carefully with respect to size composition, particularly as regards the exclusion of excessive fines. Their formation as a result of degradation in storage handling or because of crushing in .the stoker worm will increase the fly-ash nuisence.Bituminous and subbituminous coals with higher ash-softening temperatures and, often, higher ash contents have not been able to enter the domestic stoker-coal market in the Pacific northwest because clinkers are not formed readily during clinker-type underfeed-stoker burning, especially in mild weather, and because of the labor and attendant inconvenience required in handling larger volumes of ash. The work described in this report was undertaken to enable mines producing coals of the kind described to enter the stoker-coal markets. The anthracite stoker selected was one that conveys the refuse from the ash pit of the furnace and deposits it into one of two covered, dust-tight disposal cans."

Dec 1, 1945

By H. M. Smith

Data from the Bureau of Mines routine method for the analysis of crude petroleum are used to characterize crude oils. Some data are used directly while other data are used to calculate the aromatic) naphthene) and paraffin contents of the distillation fractions and the correlation index of the paraffin-naphthene portion of the fractions. The calculated properties show significant differences in composition between crude oils. The methods of calculation and interpretation of data are explained and illustrated.

Jan 1, 1966

By William L. Crentz

In a Nation-wide appraisal of coking-coal reserves and of the practicability of upgrading marginal deposits to metallurgical standards, this study of the preparation characteristics of the coals in Cambria County, Pa. , was undertaken. Over 90 percent of the coal remaining in Cambria Comity is found in the Upper Freeport, Lower Freeport, Upper Kittanning, and Lower Kittanning beds. The Middle Kittanning bed, although mined on a commercial scale in the past, is not an important bed now, as most of the remaining reserves are too thin to be mined over wide areas. For many years, Cambria County has been an important source of coal for industrial and metallurgical purposes. The) principal production comes from the Lower Kittanning bed, which accounts for almost .60 percent of the Cambria County coal output. Table 1 shows the county's coal production, by beds, during 1948.

Jan 1, 1950

By Frederick K. Allgaier

This report presents the final data from a 5-yr Bureau of Mines study designed to determine the surface subsidence characteristics resulting from longwall coal mining in a geologic environment common to the Western United States, It includes a description of the geologic setting of the study site, the mine plan, measurement techniques, and results of the monitoring program. Measured subsidence values were obtained over four adjacent longwall panels- Major subsidence characteristics such as longitudinal and transverse profiles, angles of draw, time-related subsidence development, and critical width are discussed. The maxima subsidence value of 5.8 ft was 68 pct of the mining thickness. The average angle of draw was 30°, Subsidence at the center of the first panel continued for 46 months following undermining. The lengths of the longwall panels precluded a definitive determination of the critical width and maximum possible subsidence.

Jan 1, 1988

By W. H. Blackburn

This paper describing the milling practice at the Tybo concentrator is one of a series of similar papers being prepared by the United States Bureau of Mines on milling methods and costs at the various mills in the United States. ACKNOWLEDGMENT A large part of this paper way prepared by H. M. Lewers, mill superintendent of the Tybo plant of the Treadwell Yukon Co., Ltd.

Jan 1, 1931

"The main objective of this research is to identify the mechanisms of control of respirable dust generation in coal mines. Full understanding of the mechanics of crack propagation in coal is of fundamental importance in studies of the generation and control of respirable dust.The main objectives of this fracture investigation are: 1) to determine reliable data on the fracture toughness of coal as a parameter controlling unstable crack propagation; 2) to determine fracture propagation velocity in coal providing data on the terminal velocity at which crack bifurcation occurs and fine fragments of coal material are generated; and 3) to apply the critical strain energy density criterion to model mixed mode crack propagation in coal.The development of the protocol, laboratory procedure and equipment necessary to conduct an extensive mixed mode fracture toughness testing program has been completed. About 80 mixed mode fracture toughness tests, 10 good fracture velocity records and over 50 fracture surface examination with the SME are available. The details of the mixed mode fracture toughness testing are available in a paper titled, ""Development of Mixed Mode Testing System for Geologic Materials"" which is available from the center. The average fracture toughness and critical strain energy density values for the three seams investigated to date are included in the attached Figures 71, 72, 73."

Nov 1, 1988

By A. L. Engel

In previous reports5/ of ore-testing studies, tests made by established methods on typical ores selected as representative of certain mining districts have been described in considerable detail. In addition to established test procedures, such as screen analysis, chemical analysis, microscopical examination of ores and products, sink-and- float separation, gravity concentration, flotation, ,and magnetic separation with or without roasting, it was sometimes necessary to apply other methods, such as leaching, in instances where physical separations were not feasible.

Jan 1, 1940

By Oliver A. Dibble

This paper it one of a series being prepared for and published by the United States Bureau of Mines, describing mining methods and costs at clay pits throughout the United States. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating expenditures only and not total costs. It is recognized that publication of total costs might in many instances cause embarrassment to individual operators as well as to the industry as a whole. On the other hand, operating costs are essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue. The open-pit recovery of clay for cement plants is a comparatively simple operation in comparison with underground mining of clays; nevertheless, it represents an appreciable factor in the cost of cement manufacture. The following report deals specifically with the methods employed by the Aetna Portland Cement Co., which operates cement mills at Fenton and Bay City, Mich., in recovering clay from their pit at Corunna, Mich., on the Grand Trunk Western Railway.

Jan 1, 1932

By R. F. Abernethy

Analytical results, including ash fusibility data, are presented by the Bureau of Mines for 10 major constituents in coal ash from 373 samples of commercial U.S. coals. Determinations of Si02, Al2O3, Fe2O3, and P2O5 were made by colorimetric methods, Na2O and K2O by flame photometry, Ti02, CaO, and MgO by a spectrochemical method, and SO3 by a gravimetric method. In bituminous coal ashes the silicon, aluminum, and iron calculated as oxides often make up about 90 percent of the ash.

Jan 1, 1969