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By W. W. Adams

"The main purpose in the compilation of accident statistics is to reveal conditions that may result in injury to persons or property so that remedial measures may be applied. For practical reasons it is usually found necessary to restrict inquiry to conditions which actually have caused personal injury, and to omit those which nay, but have not yet, resulted in damage, Fortunately or unfortunately, there is a sufficient number of the former to indicate the existence of hazards so numerous as to require all of the attention which the industry can devote to the subject.Two years ago, the Bureau of 'mines, in cooperation with the National Safety Council, undertook an intensive campaign to obtain more complete and satisfactory information regarding mine accidents than had theretofore been available. Since 1911 the bureau had been receiving annual summaries from all companies operating metal mines, showing, in a general way, the number and causes of accidents that occurred during the preceding year and the number of men employed at the mines. Monthly summaries of fatal accidents at coal mines were received from the state inspectors, showing the number of deaths attributed to each of 22 main causes of accidents, Information for individual coal mines was not furnished.While this information, nation-wide in scope, is indispensable because it epitomizes the progress or retrogression in the industry as a whole, and serves as a background of specialized studies, yet certain classes of acci¬dents, for example, those that are more or less peculiar to specific districts or mines, require an analysis in greater detail than is possible on the sole basis afforded by the annual summaries.The need for more specific information was realized some years ago in the State of Pennsylvania in connection with the administration of the workmen's compensation law, The mining industry is well acquainted with the val¬uable studies of accidents, particularly nonfatal accidents, in the mines of that State being conducted by Mr. Rush N. Hosier."

Sep 1, 1924

By John J. S. Sebastian

A laboratory-scale investigation was made of the basic problems involved in developing a ceramic heat exchanger to operate at high temperatures for using nuclear heat from gas-cooled process-heat reactors. Technical data were obtained on transferring heat by forced-convection from helium to air in a single-tube vitreous-alumina heat exchanger. Coolant air was passed through the annulus parallel with, and either concurrently or counter to, the flow of helium inside the tube. The data obtained pertain to removing heat from the helium. Average inside film coefficients were determined at mean surface temperatures of 200° to 1,570° F., inlet-gas temperatures of 1,450° to 2,665° F., and Reynolds numbers up to 560. The gas-to-surface temperature ratios were varied from 1.05 to 7.6. The tabulated results are shown in the appendix at the end of this report. The film coefficients of heat transfer were correlated by taking into account the physical properties of the helium at the average fluid temperature. With experimental conditions pointing to a laminar flow, the Nusselt number was found to decrease as the ratio of gas-to-wall temperature was increased to a value of 3. However, within the range tested, gas-to-wall temperature ratios above 3 did not affect the Nusselt number, regardless of the value of the Graetz number. Thus, beyond this point any increase in this ratio ceased to influence the heat-transfer relationship.

Jan 1, 1962

By D. A. Reynolds

[A few studies on the relationship of the fusion temperature of the ash of coke to that of the corresponding coal have been made on commercial high-temperature cokes. R. J. Rose3/ in 1921 compared the' fusion temperatures of the ashes of 10 coals and. the cokes produced from them and concluded tat they were in such close agreement that either figure could be used. More recently, Quarfort4/ found that the ash of coke fused at a somewhat lower temperature than that of the original coals As the ash of a coal and that of the coke produced therefrom have the same origin their chemical composition should be identical, provided that carbonization has not altered the inorganic, or ash-forming, constituents of the coal, and such alteration seems highly improbable. However, it has been shown5/ that coke is liable to contamination by iron during crushing and preparatory to sampling. Pieters6/ found that coke ash was cantaminated in this manner up to 0.4 percent. extraneous iron would lower the ash-fusion temperature because such iron may form ferrous silicate, which is readily fusible,7/ These results provide a basis for the prediction that the ash of coke will fuse at a lower temperature than that of the corresponding coil., especially if the fine grinding of the coke was done by rubbing surfaces of iron, as in a disk pulverizer or bucking plate.]

Jan 1, 1940

Provide the U.S. mining industry with technology for designing environmentally sound, low-cost in situ leach mining operations to produce copper from small, deep, and/or low-grade copper oxide deposits. Approach Investigate the feasibility of a new mining method--in situ leach mining-as an alternative to conventional mining for copper. Study fundamental leaching technology that will facilitate future commercial operations. Develop guidelines and procedures that will enable mine operators to design and evaluate in situ leach mining operations for any specific copper oxide deposit.

Jan 1, 1989

By T. M. Ruff

A prototype mucking machine designed to operate in narrow-vein stopes was developed by Foster- Miller, Inc., Waltham, MA, under contract with the U.S. Bureau of Mines. The machine, called a compact loader-trammer, or minimucker, was designed to replace slusher muckers in narrow-vein underground mines. The minimucker is a six-wheel-drive, skid-steered, load-haul-dump (LHD) machine that loads muck at the front with a novel slide-bucket system and ejects it out the rear so that the machine does not have to be turned around. To correct deficiencies of the tether-remote-control system, a computer-based, radio-remote-control system was retrofitted to the minimucker. Initial tests indicated a need to assist the operator in guiding the machine in narrow stopes. An automatic guidance system that used ultrasonic ranging sensors and a wall-following algorithm was installed. Additional tests in a simulated test stope showed that these changes improved the operation of the minimucker. The design and functions of the minimucker and its computer-based, remote-control system are reviewed, and an ultrasonic-sensor-based guidance system is described.

Jan 1, 1992

Coal, America's most abundant fossil fuel, is expected to play a key role in our pursuit of energy independence. A substantial increase in coal exploitation will be required if we are to fulfill our future energy needs. It is essential that new developments continue if stable coal prices are to be achieved and maintained. The challenge of the mining industry is to continue these developments in the face of problems related to increasing labor costs, inflation and environmental restoration. With expectations of increased activity in surface coal mining, the U.S. Bureau of Mines has authorized this study to determine the preliminary economic and technologic feasibility of underspoil haulage in area strip coal mines and to identify geologic and geographic areas where such a system could be used. These objectives were met by literature search, data-gathering visits to several active area strip mines and by analyzing various haulage systems that were superimposed on three model mines. Potential advantages of such a system include: 1) improved mine design; 2) lower mine operating costs; 3) improved land reclamation; 4) lower manpower requirements; 5) lower mobile equipment requirements; and 6) smaller, less sophisticated maintenance facilities.

Jan 1, 1975

Reduce respirable dust exposure of workmen operating auger-type continuous mining machines. Approach: An auger miner was fitted with an exhaust system which draws dust laden air through a [scruber] and discharges it behind the line curtain. How It Works: Dusty air is drawn into the space above the coal conveyor and through a scrubber, by two fans mounted side by side above the conveyor. Exhaust from the fans passes through a duct to the side of the auger miner, and into tubing that runs back and into the air return passage formed by the line curtain. See Figure 1. Of the 5,000 cubic feet per minute of air normally entering the working place, 4/5 is drawn out through the dust exhaust system. The system was installed on a Wilcox Mark 20 Miner and tested underground by personnel of the Bureau's Pittsburgh, Pa., Mining and Safety Research Center, under a cost sharing

Jan 1, 1976

By Steven W. Schmauch

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines Studied 25,340 acres of the 28,960-acre Twelve Mile Creek Wilderness Study Area (OR-003-162) in order to evaluate its identified mineral resources. The study area is located in Malheur County, OR, about 30 miles northwest of McDermitt, NV. The area is underlain by thick sequences of rhyolite to with lesser amounts of andesite and basalt flows. Bureau of Mines personnel reviewed pertinent literature, mining records, and examined the study area for possible mineral resources in geologically favorable sites. There are no organized mining districts and no record of past or current mining activity. Based on sample results, published literature and field observations, there are no identified mineral resources.

Jan 1, 1987

By Walter C. Woodmansee

The only reported mineral production in 1977 was small output of alluvial gold, valued at an estimated $54,320.2 In addition, marine shells are gathered for use in lime manufacture, although output was not reported. Proposed development of a bauxite mine and smelter, involving Rennell and Vaghena Islands, was deferred in June. Conzinc Riotinto of Australia Ltd. (CRA), in partnership with Mitsui Mining & Smelting Co. Ltd., and the Solomon Government, with- drew from the project, and Mitsui, which conducted a feasibility study and metallurgical testing of the bauxite, decided to defer further work because of slack demand for aluminum in Japan and difficulties in arranging financing. The Mitsui feasibility studies reportedly indicated that the project could be viable despite technical difficulties and relatively high initial investment costs. The project was to produce 1.5 million tons of bauxite and 600,000 tons of alumina per year from reserves totaling 60 million tans at 45% to 50% A1203.

Jan 1, 1981

By Earl C. Redman

The Juneau Gold Belt, centered on Juneau and approximately 120 miles long by 10 miles wide, stretches from Berners Bay on the north to Windham Bay on the south (fig. D-l). Access within the Juneau Gold Belt is provided by the Glacier, Thane, and North Douglas Highways. The Glacier Highway extends northwest from Juneau for approximately 40 miles to Echo Cove, and the other two roads end 5.5 miles southeast and 12.6 miles west from Juneau, respectively. None of these roads connect with other highway systems and access to other areas is restricted to airplanes, the State ferry system, and commercial barge lines. BUREAU ACTIVITIES The majority of lode gold produced in Alaska came from the Juneau Gold Belt portion of the Juneau Mining District. To evaluate the economic potential of the Gold Belt, the Bureau located 173 mines and prospects within the area. A total of 263 ad its and shafts were found and 56,650 feet of underground workings were mapped. The Bureau collected and analyzed 1,557 samples during the study. In addition, considerable detailed geologic map-ping was done in the vicinity of the mines and prospects from which ore control models were developed.

Jan 1, 2012

By William G. Hedling

The operation of electric face equipment in underground coal mines has proven to be extremely hazardous to mining personnel, including equipment operators and others working in the vicinity of active equipment. Recent industrial engineering studies* of accidents and fatalities indicate that a major contributor to this hazardous situation is noncompliance with modern principles of human engineering, particularly lack of standardization of control configurations. Control configurations differ not only among different machine types, but also among the same machine types produced by different manufacturers. This lack of standardization can produce a high incidence of error in the operation of electric face equipment, thus creating a potential source of accidents. Other examples of non-compliance with human engineering principles are the widespread use of identical black, round control knobs (regardless of the function being performed), and the inappropriate location, spacing, and labeling of controls. Any or all of these factors may place the operator in a "negative transfer" situation, which means that control manipulations appropriate for one type of machine are different from (or even the reverse of) the control movements required to produce the same effect on other machine types. This situation increases the accident potential to the operator, as well as to others in the vicinity. Accident potential is further increased by circumstances which do not allow for large error tolerance-specifically, emergency procedures. Reports of accident statistics cite operator inexperience as a primary cause of most accidents involving underground electric face equipment. Several factors contribute to operator inexperience, including: 1. High personnel turnover 2. Employee absenteeism 3. Current union practice of bidding for jobs.

Jan 1, 1974

By Reed. Donald F.

"Deposits of gray hematite occur in two districts in Talladega County, Ala., the Emauhee-Tallasochatchee and Weewoka, both in the vicinity of Winterboro, 50 miles east of Birmingham.The deposits were investigated by the Bureau of Mines in 1943 and 1944. Approximately 13,000 feet of diamond drilling was done and 6,000 linear feet of trenches excavated and sampled.A total of 13,000,000 tons of ore averaging 36 percent iron was indicated in all areas.A detailed discussion of each property investigated, drill logs, and sampling results are given in this report.In the work done in the Talladega County iron investigation, special acknowledgement is due to Paul M. Tyler, formerly regional engineer, Eastern Region, and Richard W. Smith, formerly district engineer, for aid and direction of the project; also to J. B. Clemmor, metallurgist, for diligent research work in the Southern Experiment station laboratory. All were members of the Bureau of Mines Staff.The project was conducted in cooperation with the Federal Geological Survey, whose field work was in charge of T.G. Andrews assisted by Brewster Baldwin. The able and valuable assistance of Andrews and Baldwin aided greatly in accomplishing the project.The areas investigated by the Bureau of Mines were in two districts: The Emauhee-Tallaseehatchee district, between Sylacauga and Sycamoer (marked B on fig. 1) and the Weeworka district, between Winterboro and Sycamore (marked A on fig. 1)."

Mar 1, 1949

By Terry J. Close

A mineral resource survey of the 236-mil (611-km2) Hyalite-Porcupine-Buffalo Horn wilderness study area (RARE 11 Areas No. 1-155 G, Gallatin Divide; and H, Hyalite) between the Gallatin and Yellowstone rivers in Montana, indicates there are phosphate rock and petrified wood resources (fig. 1). The area also has some potential for oil, gas, and geothermal resources. Stone and alluvium are abundant but appear to have little potential for development because other sources are available nearer to markets.

Jan 1, 1981

By C. M. St. John

A series of analyses of possible mining excavations associated with the development of copper nickel deposits of the MINNAMAX site in Northeastern Minnesota is presented. Specific areas such as roof and pillar stability and excavution orientations are addressed. The majority of these analyses were conducted using a boundary element method but some cases were also analyzed using the finite element method. Comparable results were obtained using the two methods but the boundary element method required less data preparation time and computer run time. Results of the analyses, as well as indicating the capabilities of geotechnical numerical models, provide some insights into behavior around multiple excavations in jointed rock.

Jan 1, 1979

By A. G. Kim

Methane and other hydrocarbon gases, byproducts of coalification, are emitted from coal at widely varying rates and often present ventilation problems during mining. The air in some coal mines apparently contains no methane. To determine if coals from mines which bid no history of detectable gas emission contained adsorbed methane, samples of coal at the shaft bottom and at an active face were obtained and placed in sealed metal cylinders. The atmosphere around the coal was sampled and analysed by gas chromatography. Methane, ethane, ethylene, propane, propylene, and butane were found to have been desorbed from these coals. Hydrogen and helium were also detected. An estimate of the amount of residual gas per ton A coal indicated that coal samples from the active face generally contained more adsorbed gas than coal samples obtained from the shaft bottom, although in both instances the total amount of gas was relatively small.

Jan 1, 1973

By H. Kenworthy

This report concerns cooperative milling investigations of the Central mill of the Eagle-Picher Mining &. Smelting Co, The work carried on at the Central mill and the Rolla, Station shows that: It is possible to reduce the Central mill heavy-medium plant tailings by 0.05 to .15 percent zinc; the 3/16-inch to 10-mesh fraction of the jig feed can be treated by sink-float to obtain a tailing containing only half as much zinc as the jig tailing; Humphreys spiral concentration of the flotation tailing does not recover enough zinc to be economically attractive; and crushing and wet grinding of ferrosilicon for heavy medium are commercially feasible. The Eagle-Picher Co. operates extensive mines in the Tri-State area of Missouri, Kansas, and Oklahoma. The ore is milled at its Central hill, which also accepts custom ores. During the recent war the mill handled about 12,-000 tong- of low-grade ore per day. The company milled about 50 percent of the district tonnage and purchased nearly 90 percent of the custom ore. About 50 percent of the mill feed was from company mines. Zinc is the chief value in the Tri-State ores,-with Varying quantities of lead and cadmium minerals, as well as small amounts of germanium and gallium.

Jan 1, 1949

By W. T. Benson

The Bureau of Mines has undertaken investigations to examine selected deposits of beryllium throughout the United States. The beryllium deposit about 6 miles southeast of Lone Pine in the Owens Valley region of Inyo County, Calif., was among those selected for study. In 1960, field work was conducted on the Inyo Beryl claim to determine the extent and character of the beryl-bearing deposit. This report describes the work that was done. In the area investigated, the beryl occurs disseminated in granite and limestone and as stringers. Apparently, the stringers are related to nearby pegmatite dikes, inasmuch as some appear to contain fine-Grained pegmatite. Granitic rocks enclose most of the stringers, which occur as fracture fillings, ranging from thin seams to 4 inches in thickness. The stringers are of muscovite, quartz, albite, and beryl. Some also include epidote and fluorite. For the most part, they are widely spaced. Therefore, mining of substantial tonnages averaging better than 0.2 percent beryl does not appear feasible.

Jan 1, 1962

By Eugene L. Grumer

High-expansion foam was applied to the flames of six fuels burning in a 1-foot-diameter tray. The flames of three hydrocarbon fuels were more readily extinguished than the flames of methanol, acetone, or unsymmetrical dimethyl hydrazine. The result is rationalized on the basis that heat transfer from flame to fuel surface is primarily radiative with the hydrocarbons and more largely convective with the nonhydrocarbons. INTRODUCTION Equipment for producing high-expansion foams has been developed by the Bureau of Mines to control coal mine fires.5 Recently such equipment has been redesigned for portability and has now been produced commercially for other fire-fighting applications. In May 1961, a 50-by 50-foot gasoline fire was extinguished within 2 minutes by a trailer-mounted foam unit that produced 12,000 cu.ft./min. of high-expansion (1,000:1) foam.6

Jan 1, 1962

By E. C. Hoeman, W. C. Stoecker, R. C. Redfield

"INTRODUCTION Industrial sands, characterized by specific physical and chemical proportion, are,essential new materials for the manufacture of glass, sodium siliante and other products. Sands of suitable characteristics are used extensively for molds and cores in the casting of metals as a granular medium in municipal water filters, as abrasives, as traction sand to prevent the slipping of driving wheels of self-propelled vehicles on trucks and in various ceramic and other structural forms. In addition to the use of common silicon sands in concrete, cement, and mortar, special sands find use in sand-lime brick oxychloride cement, and flooring, for coating prepared roofing, and for placing ware in saggers although sand for sandpaper has been mostly displaced by other harder mineral or synthetic grains, other abrasive uses are numerous and include sandblasting stone sawing, glass burnishing and finishing."

Oct 1, 1945

By Richard H. Bares

One criterion central to most definitions of reclamation is the restoration of mined lands to their original productive potential. This is often difficult to achieve on mined lands in the Northern Great Plains because of the rigorous climate (Bares 19;2) and various soil related problems including sodicity, salinity, soil permeability, low organic matter and plant nutrient deficiencies (Malakondaiah and Safaya 1982). Field study sites were established on recontotured mined areas during the early 1970's (prior to the topsoil mandate) in which several amendments were tested for their ability to improve spoil/topsoil conditions and, hence, increase plant production. Physical and chemical properties of these control (untreated) and amended spoils and topsoils have been summarized (Safaya et al. 1982). A number of grass and legume species combinations were studied. The general effects of one time (prior to seeding), single rate (approximately 100 mT ha-1) application of leonardite and/or slack coal to spoils and topsoils was the reduction of grass dry matter yields (NB 1 test site: dry matter yield (DMY) without slack was 110 g m 2 yr I ; DMY with slack was 80 g m -2 yr 1 I and the promotion of legume establishment and yield (SB test site: DMY without leonardite was 13 g m 2 yr -1; DMY with leonardite was 93 g m 2 yr 1). On South Beulah topsoil, treated with leonardite, production of weedy species was remarkably lower than that without leonardite (SB test site: DMY without leonardite was 252 g m - yr -1; DMY with leonardite was 177 g m 2 yr 1). The general effect of commercial fertilizer applied one time prior to seeding (rates ranging from 9-13-0 to 44-1 12-28 kg ha-1 of N-P-K) was to increase plant production during the first two to three years after which the effect disappeared. This effect was much more pronounced on spoils (NB I test site: DMY on spoils without fertilizer was 53 g m -2 yr -1; DMY on spoils with fertiliser was 132 gm -2 yr -1). Weedy species accounted for most of the biomas, production during the first growing season. Three of the test sites were designed to study plant production on topsoils and spoils. Establishment and production of grass species were comparatively better on topsoils (30 cm in depth) than on spoils while legumes were most successful on the soils (Center test site, 1979; DMY of grasses on topsoil was 170 g m 2 yr -1 DMY of grasses on spoils was 52 g m -2 yr -1; DMY of legumes on topsoil was 20 g m -2 yr -1; DMY of legumes on spoil was 191 g m 2 yr -1). Total plant production on topsoiled (302 m thickness) plots at the South Beulah site (DMY in 1979 of 269 g m 2 yr 1) was comparable to that of native western wheatgrass prairie (DMY of 262 g m -2 yr -1). An experiment was conducted to find out if time of planting would have any effect on establishment of grasses on spoils. It was fund that late fall seeding was superior to spring planting for establishment of wheatgrasses at NB 3 test site (Control Plot, 1975: DMY on spring-seeded was 1 g m -2 yr - 1; DMY on fall-seeded was 55 g m -2 yr -1). In general, wheatgrasses (slender, streambank, thickspike and western) yielded the most aboveground biomass of all the grass species tested; yellow sweetclover was the most successful legume. Yellow sweetclover established and was productive on both spoils and topsoils but only where competition with grasses was apparently minimal. Durar hard fescue established and thrived on topsoil but dry matter production was low compared to that of wheatgrasses. Emerald crown-vetch demonstrated a potential for growth on spoils where water conditions were adequate, whereas side-oats grama, prairie sand-reed, alkali sacaton, and bird's -foot trefoil demonstrated only sporadic success. Little bluestem did not become established at any of the test sites. Peak production of the planted species, especially grasses, was generally reached by the second week of July. Legume and weed production continued to increase into late August.

Jan 1, 1982