Search Documents

By Cecil E. Lester

Since the advent of coal mining, the minimal lighting in the under¬ground working place has been an obstacle to the safe and efficient performance of the miner's many tasks. Compounding this problem is the fact that the machines being operated in the working place are so large that the vertical and horizontal clearances around the machinery are severely limited. Consequently, in these poorly lighted and congested working places, the machine operator is unable to utilize his peripheral vision. He cannot see hazards as they develop and, too often, cannot react in time to avoid serious injury or death to himself or his fellow miners. The greatest hazard to miners inby the last open crosscut is from falls of roof which are often preceded by warning signs such as falling rock fragments, roof supports taking weight, or a sudden reduction in the height of the working place. These warning signs often go undectected because the machine operator's attention is focused on the small circle of light emitted from his cap lamp. Congress recognized the illumination deficiencies, and, in the Federal Coal Mine Health and Safety Act of 1969, charged the Secretary of the Interior with the authority and responsibility for development and promulgation of minimum standards for illuminating working places in coal mines. These standards have been developed and, as stated in the April 1, 1976 Notice, Federal Register, Volume 41, No. 64, will be promulgated on October 1, 1976, as mandatory regulations under Section 75.1719, Title 30, Code of Federal Regulations. The regulations require that the designated surfaces within the miner's normal field of vision be illuminated to 0.06 foot-lamberts while self¬propelled mining equipment is being operated in the working places. The term "working place" is defined in the Act as "the area of a coal mine inby the last open crosscut".

Jan 1, 1976

By E. C. Lane

The motor gasoline that is being marketed in the United States this winter is practically the same 'as that sold a year ago. In fact, there has been little char sin this commodity during the year, as the gasoline sold last summer was almost as volatile as that marketed last winter. Boring the past eight years, the Bureau of Mine's has made semi-annual surveys of the gasoline marketed in the United States, the survey just completed being the fifteenth in the series. The cities in which samples have been collected have been chosen as representative of the more important marketing territories as it is obviously impracticable to obtain a sample of every gasoline sold in the entire country.

Jan 1, 1927

By Keith L. Harris

Real gross national product3 (GNP) grew at a seasonally adjusted annual rate of 4.2% in the fourth quarter compared with a revised 4.3% rate in the third quarter, according to the most recent estimates released by the U.S. Department of Commerce (table 1). Expanding inventories, Government purchases of goods and services, residential fixed investment, and a narrowing of the trade deficit fueled the growth. Significantly reduced consumer demand led to the heavy inventory growth. Almost half of the buildup in inventories consisted of automobiles because consumers reduced purchases when Detroit ceased most incentive programs in late summer. Reduced consumer demand also affected imports, however, and the narrowing of the trade deficit resumed after widening in the third quarter. Nonresi- [ ] dential fixed investment also declined after a strong gain in the third quarter. On a year-to-year basis, the economy grew at an inflation-adjusted rate of 2.9%, the same as that of 1986. However, on a fourth-quarter-to-fourth-quarter basis, the real growth reached 3.8%, the highest growth since 19M, and exceeded the Reagan Administration's estimate of 3.4%. Rising merchandise exports accounted for about one-third of the growth in GNP for all of 1987 and are expected to continue to grow as domestic manufactures benefit from the lower value of the dollar vis-a-vis other major trading country currencies. Consumer demand became a less important factor of economic growth, but employment continued to grow (table 2), and civilian unemployment declined by 0.9 percentage points (December to December) as the industrial sector geared up to increase exports. Inflation, as measured by the fixed-weighted GNP price index, remained low at 3.4%.

Jan 1, 1988

By Alice V. Peter

Meerschaum or sepiolite is employed principally in tobacco pipes and cigar and cigarette holders, although a few other uses of minor importance are Down. The unique value of a meerschaum pipe is derived from the owner's pleasure in watching the color deepen with smoking and in having the color "set" at the desired shade. The name "meerschaum" (German for "sea foam") is applied because the material, when pure and dry, will float on water. Owing to its resemblance to the porous, bonelike structure of the cuttlefish, or septa, it is also known as sepiolite. There are a few scattered deposits of meerschaum in. the United States which have yielded a small product ion, but the world's supply of the' material is obtained fined principally from Asia Minor, Meerschaum deposits near Eski-Shehir, Turkey, are said to have been worked 2,000 years ago, but commercial exploitation is a development of the last hundred years DESCRIPTION AND PROPERTIES Meerschaum is a hydrous magnesium silicate (H4Mg2Si3010) having the following theoretical analysis: Si02, 60.8 percent; MgO, 27.1 percent; H20, 12.1 percent. It is a soft. (H.2 - 2.5), fine-grained, earthy, white, gray, or yellow material. It is very light weight when pure (specific gravity, 1 to 2) and is highly absorbent. Because of its porosity the proportion of water present in the mineral is affected by the humidity'of the atmosphere. In a moist atmosphere the water content may be as much as 21.7 percent. Then wet the material is soft and somewhat plastic. When dried again it becomes lard and tough. The toughness is especially apparent in some forms that have a fibrous or leathery texture.

Jan 1, 1934

By Industrial Research Office

"The U.S. Bureau of Mines established on August 15, 1983, the Generic Mineral Technology Center for Respirable Dust within the Mining and Mineral Resources Research Institutes (MRIs) at The Pennsylvania State University and West Virginia University in association with participating MRIs at Massachusetts Institute of Technology and the University of Minnesota. The Center's research program has been developed with recognition of the stated objective of the Federal Mine Safety and Health laws which is to ""... permit each miner the opportunity to work underground during the period of his entire adult working life without incurring any disability from pneumoconiosis or any other occupation-related disease . . . ."" The Center's program is designed to permit an accelerated attack on the fundamental research problems for the control of respirable dust in mines.The primary goal of the Center is to reduce the incidence and severity of respirable dust disease through advancing the fundamental understanding of all aspects of respirable dust associated with mining and milling and the interaction of dust and lungs. The Generic Technology Center's research program explores these concerns with the objective of refining existing strategies and developing new respirable dust control techniques that are consistent with the fundamental dust-lung interaction processes that lead to mine worker disability. The work concentrates on: (1) control of dust generation; (2) dilution, dispersion and collection in mine airways; (3) characterization of dust particles; (4) interaction of dust and lungs; and (5) relationship of mine environment, geology, and seam characteristics to dust generation and mobility. The fundamental aspects of this work are applicable to the control of respirable dust problems in both hard rock mines and coal mines and to other dusts such as diesel-generated. The Center activities involve the training of engineers and scientists, graduate students and undergraduate students through their respective institutions, and the technology transfer to the industry. The Center also serves as the reference center for publications' in the respirable dust area.The Center is composed of faculty from the four universities/institutes listed above. The personnel, facilities and equipment that are available to the Center from these entities are diverse, complementary and comprehensive. More than fifty scientists, engineers; and medical personnel in the Center are engaged in respirable dust research. Additionally, the expertise and facilities of the NIOSH--Division of Respirable Disease Studies are available as a result of the existing relationship between NIOSH and West Virginia University.The breakdown of the dust research program into the five areas mentioned above recognizes the importance of an integrated fundamental research approach to the respirable dust problem compatible and complementary with the existing and ongoing U.S. Bureau of Mines activities. The specific projects in the research areas are a result of a careful evaluation of the past and ongoing research activities, the identification of areas where data and information are scarce, and awareness of the recommendation of the National Academy of Sciences Study on the Measurement and Control of Respirable Dust. Penn State is the administrative unit for the Center. Funding to date is nearly $6.5 million."

Aug 31, 1989

By D. C. Fleck

The Bureau of Mines, in a cooperative research program with four lead companies, has investigated ferric chloride leaching of galena to prepare lead chloride for molten-salt electrowinning to produce lead metal. The hydrometallurgical-electrolytic process is an alternative to the sintering-smelting-refining process currently used to produce lead metal and avoids the environmental problems associated with a conventional smelter. During investigations on the electrowinning aspects of the work, it was noted that certain cations, moisture, and sulfate in the electrolyte affect lead metal purity, cell voltage, current efficiency, and viscosity of the electrolyte. Results of bench-scale tests are re-ported on the effects of CaCI2, CuCI2, FeCI2, MgCI2, NaCI, ZnCI2, PbS04, and moisture on electrolysis. As impurities increased in the electrolyte, current efficiency decreased. CaCI2, CuCI2, and FeC12 decreased current efficiency by 12 to 47 pct. ZnCl2 gave a small voltage increase, while CaCI2 addition equivalent to 4.9 pct Ca caused a 50-pet increase in voltage. The lead metal was contaminated in direct proportion to the CuCI2 buildup in the electrolyte, Anode corrosion was observed with MgCI2 and MgC12?6H20. Viscosity increased appreciably with the buildup of NaCI, CaCI2, and sulfate. Electrolyte foaming occurred with ZnC12, MgC12?6H20, MgC12, FeC12?2H20, and FeCI2. Moisture inhibited the coalescence of the lead metal.

Jan 1, 1983

By K. Robert Dorman

This Bureau of Mines report describes laboratory and field experimentation in building mine ventilation stoppings, air-door frames, and fan bulkheads with a civil construction technique. Shotcrete is applied to a free-standing, three-dimensional wire-truss panel, which is easily cut and rapidly erected. In mines where shotcrete equipment is available, this technique should be faster and cheaper than conventional block-and-mortar or monolithic concrete construction.

Jan 1, 1980

Provide an economic alternative to drill-blast excavation with the same ability to excavate openings of varied orientation, shape, and size. Approach Develop an efficient, adaptable, mechanical excavation machine that produces unconfined tensile failure in rock. How It Works A drill-split fragmentation machine that combines a drill and a unique splitter has been developed. The drill and splitter are mounted on a carriage that positions the splitter in a hole immediately after it is made by the drill. The splitter creates force loads that cause the rock to fragment, and the process is repeated for excavation. The unique splitter applies both radial and axial loads to the rock mass, which produces an excavation action comparable to pulling a plug. This excavation action distinguishes the radial-axial splitter from typical demolition splitters, which require a free surface parallel to the axis of the splitter toward which to break rock.

Jan 1, 1989

By L. E. Schultze

As part of its goal of maintaining an adequate supply of minerals to meet national economic and strategic needs, the Bureau of Mines devised a processing sequence for recovering uranium from carbonaceous ores. Uranium extractions of 97 pct were obtained by contacting the ore with a solution containing 400 grams of ferric sulfate hydrate in 200 ml water for 3 hr at boiling temperature (96° C). Uranium was recovered from the leaching solution by solvent extraction with tri-issooctyl amine. The barren ferric sulfate solution was recycled to the leaching system. The leaching process resulted in no detectable dissolution of carbonaceous material from the ore. Work on the project was terminated in 1978 because of a transfer of responsibility to the U.S. Department of Energy.

Jan 1, 1981

By Herbert R. Appell

Urban refuse, cellulosic wastes, and sewage sludge have been converted to heavy oil by heating under pressure with carbon monoxide and steam. Conversions of the organic matter to oil, water, and gas have averaged near 90 percent at temperatures of 250° to 400° C and pressures of 1,500 to 5,000 psi. The yield of oil, based on the dry organic matter of the waste materials, is usually near 40 percent. This is the equivalent of more than 2 barrels of oil per ton of dry, ash-free waste material. The oil from urban refuse and cellulosic wastes has a sulfur content near 0.1 percent. This low sulfur content makes the oil from refuse a desirable source of fuel oil.

Jan 1, 1970

By A. J. Strazisar

The Bureau of Mines conducted a laboratory investigation to study the effectiveness of low-pressure steam and water spray in suppressing respirable dust at the tips of a saw-type cutting wheel. Suppression efficiencies were found to be proportional to the amount of the water or steam applied at the cutter tips. For equivalent water output rates, a maximum efficiency of approximately 80 percent was reached for both steam and water spray. Results from the steam and water spray tests showed an increase in suppression efficiency with an increase in particle size of 1 to 8 micrometers. The data indicate no advantages for using steam as a dust suppressant.

Jan 1, 1972

By M. M. Tilman

The Bureau of Mines conducted research into the dispersion strengthening of lead by the coprecipitation method. Commercially available reagents in water solutions were reacted to form homogeneous precipitates of lead and aluminum compounds. The resulting precipitates were roasted to oxides and reduced in hydrogen to form mixtures of lead powder and alumina. The powders were isostatically pressed into billets which were extruded into rods. The rods were rolled into strip to provide material for testing. Alloys containing 0.5, 1, 2, and 3 nominal volume-percent A1203 were tested in short-time tensile tests and in tensile creep tests. An alloy of Pb-3 volume-percent A1203 exhibited an average tensile strength of 8,570 psi after rolling to 75-percent reduction at 125° C but had no measurable elongation. Alloys of lower A1203 content provided a better compromise between tensile strength and ductility. For example, an alloy of Pb-0.5 volume-percent A1203 had an average tensile strength of 6,590 psi with 9-percent elongation after rolling to 75-percent reduction at 125° C. Creep rates of dispersion-strengthened Pb-A1203 alloys were below 1 percent in 10,000 hours at stresses of 2,000 to 4,000 psi.

Jan 1, 1971

By B. K. Cantrell, K. L. Rubow

"Quantifying exposure to diesel exhaust aerosol in an underground coal mine depends on the ability to measure this component of respirable mine aerosol separately from coal dust. Such measurement is complicated by the carbonaceous nature of both the diesel and coal dust particulate that make up the respirable aerosol. Hence, special sampling and analytical techniques must be used to distinguish between these two aerosol components.As part of a continuing study of diesel exhaust aerosol characteristics, the U.S. Bureau of Mines has applied size selective sampling together with gravimetric analysis to separate and measure respirable diesel exhaust and coal dust aerosol concentrations in diesel-equipped underground coal mines. This technique is based on the premise that the diesel portion of the aerosol is predominantly submicrometer and the mineral dust portion is mostly greater than 1 µm in size. In the study, chemical mass balance (CMB) modeling, based on the distribution of chemical elements in aerosol and aerosol source material samples, is used to referee the analysis of diesel exhaust and mineral dust aerosol concentrations from the size selective sampling results.Based on the results of the study, the Bureau, in cooperation with the University of Minnesota and the U.S. Mine Safety and Health Administration (MSHA), have developed a prototype personal diesel exhaust aerosol sampler for underground coal mines. The sampler has three stages: a preclassifier stage to select for respirable aerosol, an inertial impaction stage with an aerodynamic diameter(d) size cut at 0.8 µm to separate diesel aerosol from mineral dust and collect the mineral dust, and a final filtration stage to collect the diesel fraction of the sample. The sampler has been evaluated in both laboratory and field experiments conducted by the Bureau, MSHA, and the Generic Minerals Technology Center for Respirable Dust (GMTC-RD)."

Mar 1, 1992

By M. G. Downey

The stone resources in certain localities and the kinds of stone available often influence manufacturing companies in their choice of plant location and in possible expansion of their activities. Limestone in particular is an important raw material for many processing industries. In planning highways and public works and placing contracts therefor, the availability of aggregates and road stone is significant. On the other hand, persons who contemplate entering the stone business or opening now quarries need information as to possible competition. To meet the growing need for regional data of this type, the Bureau of Mines has compiled from its records and presents herein the location of stone quarries by States and counties and by kinds of stone. The list covers all stationary and portable commercial quarry operations whose production statistics for 1940 were reported to the Bureau of Mines but does not include undeveloped deposits and noncommercial or Government-operated quarries.

Jan 1, 1941

By James L. Hendrix

A study was made of the United States Bureau of Mines' chlorine-oxygen leaching process for complex sulfide concentrates. The investigation sought to determine the kinetic order and IT mechanisms involved in the reactions betweens sphalerite, and galena with chlorine. The influence of copper on the extraction rates was also studied. It has been shown the rates of reaction of chlorine in aqueous solutions with sphalerite and galena are both zero order at 373K with the rate limiting step being the chemical reaction. Addition of cupric chloride increased the extractions of both lead and zinc.

Jan 1, 1980

By Harry W. Campbell

During 1983, the U.S. Bureau of Mines conducted a mineral survey of 19,700 acres that included the Fish Creek Mountains WSA (Wilderness Study Area), 15 miles southwest of the Salton Sea. Two United States Gypsum Co. claim groups in the WSA have more than .20 million tons of inferred gypsum reserves. These high-grade, surface and near-surface gypsum deposits are an extension of a gypsum bed that has been mined continuously since 1922. The Waters prospect in the central part of the WSA has large quantities of limestone suitable for many commercial uses. Sand and gravel is plentiful in the WSA in alluvial fan and ancient shore-line deposits. Limestone and alluvial deposits are not economic because similar material is closer to potential markets. No evidence of energy minerals or geothermal resources was identified in the WSA. A portion of the eastern Fish Creek Mountains WSA is leased for oil and gas exploration. United States Gypsum Co. holds eighteen unpatented placer claims in the northwestern part of the WSA. No other mining claims or mineral leases were identified in the study area. No mineral production is known from within the WSA.

Jan 1, 1986

1. In 2003, a total of 4,357 stone mining operations reported employment to the Mine Safety and Health Administration (MSHA). The major industrial classifications in stone mining are dimension stone (used for construction purposes), crushed and broken stone (aggregates), cement, and lime. • Stone mines comprised 30.3% of all mining operations. • Mines producing crushed and broken stone (n = 3,412) comprised 78.3% of all stone mining operations.

Feb 1, 2005

By Gerald L. Finfinger, Syd S. Peng

Geology is an integral part of roof control, mine design, and production operations. Yet, the importance of geology, coal/rock as an engineering construction material and its properties and behavior within the planned mine areas, in overall mine production operations has not been hilly appreciated. Of all of the engineering disciplines, mining engineers work with the most challenging construction materials. They must deal with rock materials as they exist in their natural states and design mine structures without well-known and defined properties. Further complicating the design process is the variability of the in-situ rock materials with rock types and rock properties varying widely from place-to-place. Predicting properties in advance of mining is difficult and oftentimes impossible. This is why some types of roof-control failures may suddenly occur in some areas when a single roof-control technique is consistently applied to an entire panel, section, or mine. Many roof-control techniques are primarily applicable to the geological conditions that were assumed in the development of those techniques and variations of the rocker rock properties may require modification or significant redesign of the support technology.

By G. R. Hopkins

"The average heat requirement per barrel of crude refined in the United States rose from 579,000 B. t. u. in 1940 to 584,000 B. t. u. in 1941. This marked the second successive year in which there was an apparent loss in fuel efficiency at refineries. This ""loss"" took place despite an increase in crude runs, which used to be an invariable indicator of a lower average.Probably the chief factor in the increased heat requirement in 1941 was the gain in the over-all gasoline yield from 43.1 percent in 1940 to 44.2 percent in 1941. Possibly another important factor was the further use of obsolete equipment to increase throughput.The refiners used more of all kinds of fuel excapt coke in 1941 than in 1940. However, the only fuels which increased materially in relative importance were refinery gas, which contributed 51.6 percent of the total heat units in 1941 compared with 50.7 percent in 1940, and natural gas, the share of which rose from 17.1 percent in 1940 to 18.0 percent in 1941. The changes in the percentages for the other fuels were as follows: Oil decreased from 25.7 to 24.1 percent; acid sludge fell from 2.7 to 2.5; coal remained at 3.4 percent; and coke (including steam) fell from 0.5 to 0.4 percent.New records for fuel efficiency were set in all three of the districts east of the Mississippi, namely, East Coast, Appalachian, and Indiana, Illi¬nois, etc. All the ether districts reported higher average fuel requirements in 1941, except the Louisiana Gulf and Arkansas-Louisiana inland.Since the year of the first statistics, the refiners have steadily increased their purchases of electricity. In 1941 total purchases were 1,862,996,000 kilowatt-hours, or 11 percent more than in 1940."

Apr 1, 1943

By D. C. Fleck

This report describes a method of using sodium for reducing titanium tetrachloride, developed at Boulder City, Nev., as part of the Federal Bureau of Mines effort to improve the extractive metallurgy of titanium. Finely divided titanium metal, titanium lower chlorides, or a mixture thereof was produced in a continuous operation at temperatures between 105° and 205° C. by the reaction of molten sodium and vaporized titanium tetra-chloride in an agitated bed of finely divided inert solids (powdered sodium chloride or the reaction products). Composition of the product was controlled by varying the relative quantities of sodium and titanium tetrachloride used. A description of the operations and analytical data of the reaction products are given.

Jan 1, 1960