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By W. C. Holliman

This report on the characteristics of commercial aviation gasolines presents compilations of inspection test data furnished on their products by manufacturers of commercial grades of aviation gasoline, and special data obtained in Bureau of Mines laboratories on samples of these gasolines. Data and physical samples for the survey were submitted by 15 manufacturers on 18 grade 80, 21 grade 91/98, 22 grade 100/130, and 10 grade 115/145 aviation fuels.

Jan 1, 1948

By O. M. Bishop

"INTRODUCTION Early in World War II, the Bureau of Mines realized that reserves of fluorspar ore at many mines in the southern Illinois fluorspar district were not being developed as rapidly as the old ones were being depleted. At some mines the measured and indicated ore reserves were almost entirely depleted, although geologic factors favored new discoveries. The Leo mine, which had not been worked since 1938, was among this group of mining. The Bureau of Mines, together with the Illinois Geological Survey examined the property, studied the mine records and,geologic factors in 1944, and agreed that exploratory drilling was warranted Funds were,obtained for the work in the fiscal year 1945, and drilling was done; between October 27, 1944, and June 15, 1945.The property was owned in fee simple by the Hllside Fluor Spar Mines at the time exploration was begun in October 1944. Subsequently, in 1945, the Inland Steel Co. acquired of the Hillside property."

Jan 1, 1947

By M. J. Beus, M. K. Larson, J. K. Whyatt

U.S. Bureau of Mines researchers reviewed an in situ stress estimate developed from measurements of overcore strain taken at test sites on the 7300 and 7500 levels of the Star Mine near Mullan, ID. Although the field measurements of overcoring strain were found to be useful, significant deficiencies were found in the stress estimation procedure. A new stress estimate was developed incorporating statistical methods and an improved understanding of stress concentration factors for interpreting overcore strains recorded by doorstopper cells. Spatial variability of overcore strains and the implications for stress field variability were explored.

Jan 1, 1995

By William M. McKewan

The U.S. Bureau of Mines has established a wire rope research laboratory to examine the factors that affect the life of wire rope. Ropes of sizes ranging from 3/4 to 2 in. in diameter and from 2 to 35 ft in length were tested to determine their breaking strength, elongation, and torque. This was done to characterize the test equipment on ropes used in mine hoisting systems.

Jan 1, 1990

To provide a means for mechanically separating and recovering nonferrous metals continuously from non-magnetic reject material produced at scrap automobile shredding facilities. Approach The Bureau of Mines developed a water elutriator system that separates metals from shredded scrap auto-mobiles based on differences in specific gravities. A premium-quality product, containing aluminum, magnesium, lead, zinc die cast, copper, copper alloys, and stainless steels, is obtained. How It Works Mixed nonmagnetic reject material currently being separated at automobile shred-ding facilities is introduced onto the top of an upwardly flowing vertical column of water. The water, overflowing a weir in the top of the vertical column, carries with it the floating, lightweight waste materials, mostly combustibles, while the heavier pieces sink through the rising water. Medium-density substances such as glass, rubber, and heavy plastics are carried off through a side port, located in the upper third of the column. The cleaned, mixed metal product sinks to the bottom and is continuously removed from the base of the column with a bucket elevator having perforated buckets. All three categories of material are removed from the system on separate wire mesh belt conveyors. Most of the water drains through the belts into a holding tank and, after settling, is recirculated back through the elutriator column. The purity and recovery of the metal product are influenced by two elutriator operating variables: the flow rate of water through the vertical column, and the height of the overflow weir at the top of the column.

Jan 1, 1983

By Fun-Den Wang

A two-dimensional plane strain analysis by the stiffness matrix method was used to analyze two basic pit slope configurations. The magnitudes and the directions of stresses are given for a V-shape and for a flat-bottom pit with the slope angle varying from 30° to 90° at 10° intervals, Stress effects due to irregular pit configuration or to in-situ forces are discussed. Equations of similitude for gravity loading are given. Expressions are also given for the stresses at the toe as a function of slope angle. Procedures are given for finding the stresses in any geometrically similar pit slope of different dimensions and material properties from the stresses and equations presented in this report. Numerical results show that the V-shape pit slopes have lower stresses than the flat-bottom pit slopes; hence, they are inferred to be more stable.

Jan 1, 1970

By Dean H. Ambrose

[Mining and processing earth's materials form the basic building blocks from which many technology advancements and products are made. Virtually all metallic and non- metallic products are derived from a substance found in our earth that we blend, mold, extrude, or pulverize into something useful, the mining industry is responsible for the first step of this process: extraction from the ground. Mining particularly coal mining. poses significant risks to both humans and machines. As raw materials are]

Jan 1, 2009

By G. L. Neumann

In October 1949 the College Park Branch of the Mining Division instituted a survey of the New England pegmatites. Many of the New England pegmatite deposits were superficially examined, and the Bumpus quarry in Albany, Oxford County, Maine (see fig. 1), was selected for a diamond-drill exploratory-development project to supply information for developing more economical mining methods and no increasing production of beryl and other scarce minerals associated with pegmatitic intrusives. The Bumpus quarry has been mined intermittently by three operators since it was opened in 1927. At the time of drilling, the vein or dike (see figs. 2 and 3) had been mined to a depth of 60 feet for a strike length of 280 feet. The dike averages 40 feet in thickness and dips 50 degrees southeast. The Bureau of Mines drilled seven diamond-drill holes between September 27 and November 27, 1950. These holes showed that the dike persists for at least 350 feet to the east and probably 200 foot to the west of the present excavation. The drilling also indicated that the dip, as exposed at the surface, continued unchanged at 500 to a depth of at least 50 foot below the pit. The dike was not delineated, although it fingered out as pegmatite interbanded with Granite, diorite, and gneiss in diamond-drill hole B-4, approximately 250 feet west of the pit. Further drilling will be necessary to find the extent of this pegmatite dike and to determine the safest and most economic mining system.

Jan 1, 1952

By John P. Harmon

Vehicles traveling on untreated dirt and gravel roads at open-pit mines disseminate high concentrations of dust (fig. 1). Excessive dust creates safety hazards by reducing visibility and may endanger the health of the men who breathe it. If the dust contains free silica, it can cause silicosis. In addition, maintenance costs of mechanical equipment are increased if equipment is operated in extremely dusty places. Dust on haulage roads in hot, arid country can be controlled if the surface of the road is sprinkled frequently and adequately with water. Often, when roads are sprinkled with water to control the dust, hazards are caused through reduced traction and skidding because of the mud that is formed on the surface of the road. Reducing the amount of water used will help to reduce the hazard of skidding.

Jan 1, 1957

By Robert H. Merrill

This Bureau of Mines report summarizes the design and tests of a gage that will simultaneously measure the deformation of a borehole along three diameters 60 degrees apart; the measurements are in a single plane normal to the axis of the borehole. The inherent errors in measurement are considered together with the problems associated with the use of the gage in the relatively severe environments in and around mine openings. These problems were treated in the design and tests of the gage and the results establish that the gage can be used to satisfactorily is determine estimates of the stresses in rock.

Jan 1, 1967

By Frederick M. Fowkes

Dusts can be filtered out of air streams onto polymer surfaces by electrostatic trapping resulting from the spontaneous transfer of electrons upon contact between dust particles and the polymer surfaces. Such spontaneous contact electrification has been studied quantitatively in this contract with the aid of modern semiconductor charge-sensors with the aim of determining what basic principles govern the sign and magnitude of contact electrification. Information obtained by capacitance-voltage measurements of thin polymer films on silicon showed that charges as large as 4 x 1012 electrons per cm2 develop spontaneously, and that such a charge gives adhesional forces of 165 pounds per square inch (11 atmospheres). Direct measurement of dust polymer contact electrification, using silicon surface channel conductance sensors, also showed spontaneous charges of more than 1012 electrons per cm2. Some polymers can either donate or accept electrons. These included chlorinated polyethylene, chlorinated polypropylene, polyethylmethacrylate, and a copolymer of maleic anhydride with n-octadecylvinylether. Other polymers never accepted electrons but could donate electrons; these included polystyrene, pulychlorostyrune, polyvinylchloride, polyvinylacetate, a polycarbonate (Lexan), and cellulose tributyrate. Contact electrification studies were made with dusts (coal dust, a channel black, or a silica powder) contacting thin films of various polymers solvent-cast onto the semiconductor charge-sensor. Sometimes charging was instantaneous and sometimes slower, but in all but one case (coal dust on a copolymer of maleic anhydride with n-octadecylvinyl ether) the charge trunsfer was a donation of electrons by the polymer to the dust. Some

Jan 1, 1973

By W. W. Adams, V. E. Wrenn

"Production of explosives in the United States during the calendar year 1936, as represented by reports of sales by manufacturing companies, totaled 391,604,500 pounds, an increase of 27 percent over the amount produced during 1935. This quantity included 81,698,375 pounds of black blasting powder (granular and pellet), 262,047,106 pounds of high explosives other than permissibles, and 47,859,019 pounds of permissible 5/ explosives.The manufacturers' reports to the Bureau of Mines classify the sales of explosives according to five main classes of work in connection with which the explosives were used.Coal mines used 87 percent of the total amount of black blasting powder sold, bituminous-coal mines 79 percent, and anthracite mines 8 percent; coal mines also consumed 98 percent of all permissible explosives and 9 percent of the high explosives other than permissibles. The coal-mining industry consumed 16 percent more explosives in 1936 than in the preceding year, the increase at bituminous mines being 21 percent and that at anthracite mines 4 percent.Metal mines used 29 percent of the high explosives other than permissibles and less than 1 percent of the black blasting powder and permissible explosives. The total quantity of the three classes of explosives used in metal mining in 1936 was 36 percent more than the quantity so used in 1935."

Jul 1, 1937

By D. K. Steele

An 18-in-diam column water elutriator was designed, tested, and operated by the Bureau of Mines for recovering nonferrous mixed metals from automobile shredder rejects. The waver elutriator separated metals from nonmetals contained in shredded nonmagnetic rejects. The unit was constructed and integrated into a local automobile shredding operation. Nonmagnetic rejects from the automobile shredder were fed onto the surface of a column of rising water. Dense materials fell through the rising water and were collected as a sink product at the bottom of the column; medium-density materials were removed as an intermediate product in a water flow through a discharge port located between the overflow and sink; and light materials were immediately carried out in the overflowing water at the top of the column as a float product. Nearly 99 pct of the mixed metals were recovered from the nonmagnetic rejects as a 70-pct-metal concentrate. Other operating conditions yielded a 93.7-pct-pure-metal product resulting in a 93.1-pct metal recovery. Float rejects are combustibles, light plastics, foam rubber, and minimal amounts of coated and uncoated copper wire. The middling discharge contained mainly medium-density rubber, plastics, glass, rock, coated and uncoated copper wire, and frequently some thin-sheet stainless steel and wrought aluminum. Maximum metal recovery in the operating program was achieved using a water velocity of 52 fpm (650 gpm). Maximum purity was obtained with a velocity of 88 fpm (1,100 gpm). .Water was recycled through a 12,000-gal baffled clarifying tank. Entrainment water losses with the float and middling rejects averaged 50 gpt of reject feed. Records maintained by the shredder operator show a 34-pct increase in nonmagnetic metals recovery during a 1-yr operation of the water elutriator as compared to recoveries from a previously used air classification system.

Jan 1, 1983

By Wallace W. Roepke

Research on coal cutting at the Bureau of Mines Twin Cities Research Center (TCRC) has evolved from a purely mechanical approach, specifically to reduce dust or frictional methane ignitions, into an understanding of the complexity of the cutting system relationships. Achieving an understanding of these relationships requires a wide variety of testing techniques and equipment. Laboratory facilities and the associated equipment exist for shallow to deep cutting in both coal and coal-inclusive rock with any desired bit type. Research efforts with this equipment are providing insight for significant advances to help solve the problems of pneumoconiosis and frictional ignition. This effort will ultimately affect both respirable dust and methane ignitions at the face through better bit design and will increase the salable percent of run-of-mine (ROM) coal processed. It will also affect the design of rotary-drum cutting continuous mining machines (CMM) and longwall machines. This report describes the main features of the coal cutting research facilities at TCRC.

Jan 1, 1983

By Oliver Bowles

The exingencies of a world war have brought home to the American public, especially the people of the. Eastern States, the urgent need for conserving fuel. Transportation problems in the East have created an unprecedented situation wherein fuel-oil supplies are greatly restricted, and the consequent increase in demand for coal further complicates the problem of transporting and storing that commodity. People should awaken to the need for utilizing every possibly means of conserving to fuel, even to the extent of reducing the temperature in their homes.

Jan 1, 1942

By G. St. J. Perrott, G. W. Jones

"In the course of its investigations pertaining to the promotion of safety the Bureau of Mines is actively engaged in investigating all promising materials that may be of value in rendering methane or other combustible gases, vapors, or solids less inflammable.Added substances are of value if such additions narrow the limits of inflammability, raise the ignition temperature, lower the speed of propagation of flame, or reduce the maximum pressure developed. Of major importance is the effect of added materials on the limits of inflammability, because methane is the chief combustible s liberated in mines, considerable work has been done with extinguishing agents on methane flames. For obvious reasons, a substance to be of value for the extinction flames should be a gas, or a liquid having a sufficient vapor pressure to give concentrations of the vapor in sufficient amounts to extinguish the flames or markedly narrow the limits of inflammability. The substance should be nontoxic, cheap, and noncorrosive and must be incombustible. Solids, such as rock dust, are undesirable and of little value for combustible gases because they soon settle out of the atmosphere, and their flame- extinguishing value is thereby lost. There are at present only a few gases and vapors-for example, nitrogen, carbon dioxide, and carbon tetrachloride-which meet these requirements.The extinction of methane flames by nitrogen, carbon dioxide, and argon has been reported by Coward and Hartwell 4; the extinction by water vapor by Coward and Gleadell 5, and the extinction by helium and carbon tetrachloride by Coward and Jones 6."

Oct 1, 1930

By Robert A. Miller

This computer program determines the price per ton of coal needed to obtain a profit of 12 percent discounted cash flow. From a predetermined equipment and manning list, the program calculates all costs and prints seven tables, Including the equipment and manning tables and the discount cash flow table. Forty-four of the input variables may be readily changed to study their effects upon the final price per ton of coal or upon individual cost items. The method is adaptable for any type of mining and with additions, for beneficiation processes. This program was written in Fortran IV for use on the IBM 11302 and with few modifications can be used on other computers.

Jan 1, 1971

By D. A. Wilson

A process was developed on a laboratory scale in which a solid waste byproduct from refining of secondary lead was converted into three valuable products. Roasted lead blast furnace matte was leached with water to recover copper. This was followed by brine leaching to recover lead. Residues were finally smelted to yield pig iron. Copper was precipitated as cement copper and the lead product obtained was a mixture of pure 3PbO.PbC12.xH20 and Pb(OH)C1. Copper recovery was 89 percent and lead recovery was 96 percent.

Jan 1, 1967

By Richard J. Kline

The underground mining industry is presently using the fluid network analyzer and digital computer to analyze ventilation systems. The availability of the digital computer and ventilation programs to mining companies has escalated its use, permitting the design and modification of new or existing mine ventilation systems to be projected completely and thoroughly with consistent precision. Because the analog computer has been analyzing ventilation systems accurately for many years, a comparison of the analog and digital methods was warranted. This report summarizes a detailed comparison for one mine, based on parallel analyses by the two computer systems.

Jan 1, 1972

By A. Aly Selim

This report describes the feasibility of predicting percussive drilling rates by equations derived from statistical regression analysis. The least squares statistical method was used and the analysis was performed both by direct and by stepwise linear regression analysis. The predicted penetration rate is a function of the drill power and the physical properties of the rocks penetrated. The results show promise that the technique may be of value in providing a mathematical model by which percussive drill manufacturers and users can predict the performance of a given drill. Experimental work involved two mining type percussive drills. Penetration data for these drills were determined from nine rocks drilled in the laboratory. Drill work rates (power) were determined in a separate series of experiments. Rock physical properties were measured from diamond-drill core samples taken from the same blocks used for percussive drilling.

Jan 1, 1970