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By D. S. Kingery

The data obtained from this study cover test areas that are gassy to ultragassy and pillared areas of different sizes and degrees of tightness. The methods of controlling ventilation, applying bleeders, and supporting bleeder entries varied in the different test areas. It was not possible to study all conditions likely to be encountered in coal mines. Undoubtedly, there are areas where bleeder entries, even though properly planned and maintained, might prove unsatisfactory. However, on the basis of this study, the following observations were made: 1. Tests showed that each bleeder system studied provided some movement of air through the pillared area; the quantities of air delivered to the pillar line, ranged from 23 to 82 percent, depending mainly on the extent to which bleeder re-turns were used as main returns from the section. 2. Pressure measurements taken across pillared areas showed maximum pressure drops ranging from 0.05 inch of water for a shallow gob to 2.69 inches for a very deep gob. The pressure differentials varied with the size and tightness of the gob but proved adequate to induce airflow across worked-out areas or through fringes of the gob to the bleeder return system.

Jan 1, 1957

By A. May

Florida has accumulated about 400 million tons of phosphogypsum, a mineral process waste generated in the production of fertilizer, and is adding 30 million tons to this annually. To minimize storage of this waste and reduce potential environmental effects, the Bureau of Mines conducted research into utilizing the phosphogypsum, by identifying and developing high-volume uses for this material. Admixtures of phosphogypsum, fly ash, and lime that could produce a coarse aggregate suitable for road construction were investigated. Using phosphogypsum with asphalt, cement, cement-kiln dust, silica, clays, and oxychlorides to pro-duce aggregate was also examined.

Jan 1, 1985

By John R. Benham

The Blue Joint Mtn. RARE II area may contain barite resources. One claim, the Woods Creek Barite No. 1, contains two veins of barite of drilling mud quality. The quantity of barite present could not be determined due to limited surface exposures. Sections 1, 2, 11 and 12 of T. 2 S., R. 23 W. in the study area are classified by the U.S. Geological Survey as prospectively valuable for geothermal energy resources. These sections border Blue Joint Creek Hot Springs, which are outside the study area.

Jan 1, 1981

By Benjamin W. Haynes

The Bureau of Mines conducted research to devise technology for increasing the Nation's mineral supply by recovering valuable constituents from currently discarded waste materials. Municipal solid waste (MSW), presently a major disposal problem, represents a significant source of metals, glass, and a combustible fraction that can be used to supplement coal in generating heat and electricity. As part of the total metallurgical system to treat MSW, this study evaluates the combustible fraction of MSW to characterize the various combustible components and to identify the principal sources of elements that eventually may be objectionable from corrosive or environmental considerations. Several possible sources for cadmium, chromium, cobalt, copper, lead, nickel, and zinc have been tentatively identified. These sources are pigments, inks, paper stock, and additives to plastics. A correlation between industry consumption values and measured concentrations in MSW was found for several elements.

Jan 1, 1978

The REL of 1 mg/m3 for respirable coal mine dust does not assure a zero risk for the development of occupational respiratory diseases among all miners exposed during a full working lifetime. Consequently, a medical screening and surveillance program that includes initial and periodic chest X-rays and spirometric examinations is important for the early detection of disease and the prevention of "material impairment of health or functional capacity" [30 USC 8 11(a)(6)(A)]. The medical screening and surveillance program is also useful for disease surveillance, which includes the tracking trends, the setting of prevention and intervention priorities, and the assessment of prevention and intervention efforts. NIOSH encourages both underground and surface coal miners to participate in the medical screening and surveillance program.

Jan 1, 1997

By R. E. Morgan, J. F. Barkley

"INTRODUCTION In city smoke-abatement work it is customary to require approval of the sizing of fuel-burning equipment. This is to insure that, with reasonable attention, the equipment can be operated essentially smokelessly, having such features as ample furnace volume and air supply. To answer the many inquiries that come to the Bureau of Mines as to what dimensions are acceptable and standard, the requirements of a number of smoke-abatement ordinances have been tabulated.CONCLUSIONSStudy of these tabulations shows that even after many years of fuel-burning practice and experience there is no common standard. Variations in the requirements for the same type of equipment under the same conditions of operation are great. This causes considerable difference in installation costs. Over-all costs being affected, the competitive positions of different types of fuel-burning equipment are also affected. It is apparent that there is a lack of information as to proper dimensions that is commonly accepted as authoritative.DISCUSSIONTable 1 gives the minimum furnace-setting heights required by various cities for mechanical underfeed stokers installed under H.R.T. boilers. Figure 1 shows a typical installation. The dimension given for each case is the distance from the dead plate of the stoker to bottom of boiler shell, unless otherwise noted. As shown in the table, different cities use different size-classification systems; it is not possible to make complete, exact, direct comparisons. Table la gives a comparison for various cities, showing the approximate percentage difference in H.R.T. furnace-setting heights required from those recommended by the Stoker Manufacturers' Association arbitrarily chosen to serve as a basis of comparison. The percentages are approxi¬mate because they were calculated as if all heights as given were measured from the dead plate of the stoker. In two cases a lower height is permitted, in a number of cases the height may be the same, and in a number of cases the height must be greater. The percentage increase goes to 100 in one case. Lack of uniformity is quite evident."

Mar 1, 1950

By A. B. Needham

The Great Eastern nickel deposit is located in the western foothills of the Virgin Mountains in the Copper King or Bunkerville district situated in the southeastern part of Clark County, Nev. It is covered by a group of eight claims that can be reached by turning south from U. S. Highway 91 at Riverside, Nev., and driving about 12.6 miles southeast over a winding mountain road, which rises from about 3,000 feet to 4,000 feet in elevation. The climate is dry, with only a small amount of rainfall throughout the year. The temperature ranges from hot during the summer to short periods of freezing weather during the winter months. The vegetation is of the desert variety, and no timber is available for mining. Water for mining purposes would have to be pumped from lower areas. A granitoid gneiss comprises the largest part of the rock outcrops. It has a steeply dipping foliation that strikes about N. 75° E. The gneiss was intruded by basic dikes, which in turn were intruded by pegmatite dikes. The ore occurs as lenticular bodies formed by the convergence of several pegmatite dikes within the main dike. The principal sulfide minerals are pyrite, pyrrhotite, and chalcopyrite, which contain a small amount of nickel. Late in the year of 1939, the Bureau of Mines undertook an exploration project on the Great Eastern property to extend or delimit the known mineralization. Underground work, consisting of 590 feet of drifting and crosscutting, was completed in September 1940, and 1,091 feet of diamond, drilling for downward extension of an ore body in the Lower edit, which was completed in February 1941.

Jan 1, 1950

By A. J. Farstad

The use of radio signals for underground communications was considered as early as the mid-1920's [1] - [4] . However, early experiments did not produce promising results with the type of equipment that was available then [5] . With advancements in solid state technology many of the schemes considered impractical in the early days suddenly became practical. The properties of electromagnetic wave behavior in conducting media have been intensively studied by Wait [ 6] and others and can be utilized not only in communication with trapped miners, but also as a means of locating their position. This report deals with the development of portable electromagnetic equipment, powered by the miner's conventional lamp battery, which can be used to alert surface rescue personnel of the trapped miner Is location. The Westinghouse Georesearch Laboratory (WGL) under BUMINES sponsors hip initially approached the trapped miner location problem using seismic techniques. It was learned from this effort that two serious shortcomings of seismic techniques are (1) the extremely weak signals available on the surface from miner generated hammer blows, requiring long processing times at the surface receiver, and (2) the relatively slow procedure of deploying geophone arrays to sense the seismic uplink signals. By contrast, the electromagnetic techniques have proven much more practical from a deployment time standpoint and in most cases have also proven to be more accurate in determining location. Furthermore, these techniques have been successfully tested using a receiver in a heli- copter for reconnaissance purposes. However, before any electromagnetic location technique can become fully operational, the miners themselves must be equipped with emergency transmitters to be carried with them on each work shift. Consequently, much emphasis has been placed on the development of extremely lightweight transmitting equipment. The performance of some of the electromagnetic location equipment developed by Westinghouse will be described in the following sections. 2.0 Basic Concepts Theoretical concepts for locating magnetic dipoles in the earth have been treated by Wait [ 7] and Olsen [ 8] . A generalized curve for the attenuation of magnetic fields in a conducting half-space is derived from

Jan 1, 1973

By Forrest T. Moyer

THIS CHAPTER of the Minerals Yearbook contains injury experience and related employment information for the coal-mining, coking, oil and gas, peat, and native asphalt industries in the United States for 1962. Injury experience is measured by the number of injuries sustained per million man-hours of exposure in each industry. No attempt has been made to combine these data and present rates reflecting the mineral-fuel industries because the hazards of the separate industries are not comparable. Tabulations showing the trend of injuries and employment for all mineral industries are presented in volume III of the Minerals Yearbook. COAL The injury-frequency rate for the coal-mining industry of the United States increased less than 2 percent, according to reports received by the Bureau of Mines. The number of fatal and nonfatal injuries per million man-hours in 1962 was 45.86, based on final data for anthracite mines and preliminary data for bituminous coal and lignite mines.

Jan 1, 1963

The object of this program was to extend the capabilities of visual paging systems both in size and function. The system developed uses the mine pager phone line for communication, monitoring, and remote control. A central station, using a mini-computer, transmits signals by phase inversion modulation of a 16,384 Hz carrier to as many as 999 remote units. The remote unit addressed returns an echo to indicate that it is functioning and, in the case of monitor units, to convey the monitor data. Magnetically latched display discs, which can be seen from both sides when posted, are used for visual paging. Lists of the addresses of posted pages, unanswered pages, and non-echoing units are prepared by the central station computer. The system was designed to be intrinsically safe and should operate for three months on a 12-volt lantern battery.

Jan 10, 1980

By James P. Ulery

A Bureau of Mines geologic study of Pennsylvanian and Permian coalbeds in southwestern Pennsylvania was undertaken to determine the effects of coalbed geology and petrology on in situ coalbed gas contents. Data were obtained from 18 coreholes from parts of four 7.5 ' quadrangles in southwestern Washington and northwestern Greene Counties, and from a single corehole in Westmoreland County. A total of 88 samples from 24 coalbeds were collected for direct-method testing to determine gas content. The samples were also analyzed for petrographic composition, chemical composition, and vitrinite reflectance values. Corehole information was used to generate isopach maps and geologic cross sections useful in data interpretation. Results of the investigation show that coalbed gas content is related to vitrinite reflectance, but not to petrographic composition. Gas contents are also influenced by other geologic factors such as roof rock lithology and competency, and location with respect to local fold structure.

Jan 1, 1989

By Charles L. Kimbell

Following the pattern established in the 1989 edition of this study, the concept of data availability must be addressed, because there are perceptible changes from year to year, and the availability of accurately reported, precisely defined statistics and nonstatistical information provides the only sound basis for analytical studies of any type. As the countries of eastern Europe, including the numerous states that formerly comprised the U.S.S.R., undergo the transition from centrally planned economies' to market economies, there has been a perceptible increase in information availability for rather obvious reasons. Any industrial operation seeing economic assistance from government and/or private sources outside the country in which the facility is sited must provide some appraisal of its operations at the time it seeks assistance, as well as some information on previous performance to serve as tools in evaluating its potential under the proposed development scheme for which it seeks financial assistance. This situation, coupled with governmental recognition that concealment of much of the national mineral production, trade, and consumption data for purposes of national security probably never was really necessary and certainly proved unnecessary with the end of the so-called cold war, has led to the publication of increasing amounts of both statistical and nonstatistical information in the countries undergoing economic transition.

Jan 1, 1993

By A. F. Colombo

The differences in starch demands that occur between ore types subjected to the anionic flotation of calcium-activated gangue and the range of residual starch contents expected to give the best metallurgical response were evaluated on a batch and pilot plant basis. A phenol-sulfuric acid procedure was used to determine the residual starch contents in the iron ore slurries. Three pilot plant campaigns on samples from a group of orebodies located on the Marquette Range, Michigan, showed that in the rougher flotation pulp, a residual carbohydrate range of 25 to 100 ppm, which is equivalent to a 0.5 lb/short ton spread, yielded optimum results. Concentrates assaying at least 65 percent Fe and less than 6.0 percent Si02 and containing more than 80 per-cent of the recoverable iron were obtained. Both batch and continuous research indicated that starch adsorption is calcium modulated and relatively unaffected by the fatty acid additions employed. Residual starch level is not a critical control factor, but the addition must be adjusted to about 25 to 50 ppm residual starch and kept in this range for most effective utilization of the added tapioca flour.

Jan 1, 1972

By James W. Townsend, William H. King

"INTRODUCTION As a byproduct of its mineral investigation program, the Bureau of Mines has developed a number of operating devices and techniques worthy of note. This paper, prepared under the direct supervision of Paul T. Alisman, chief, Salt Lake City Division, Mining Branch, and under the general supervision of Lowell B. Moon, chief, Mining Branch, reports upon ore such technique.The Wright borehole-surveying instrument developed at the Homestake mine, Lead, S. Dak., has been described in several publications. 3/ For the benefit of those to whom the publications are not available, the instrument is described here. However, this article will be concerned mainly with the technique developed by the Federal Bureau of Mines for using the instrument.In the use of the Wright borehole-surveying instrument, it was found advantageous to develop a standard practice of operation covering type of film, preparation and care of film, loading film in instrument, placing instrument in container, exposure time, unloading film from instrument, development of film, and determination of dip and strike from film impressions."

May 1, 1947

By Kevin Connor

The Government's ban on all commercial mining operations, except for small-scale artisan exploitation of alluvial gold deposits, continued throughout 1985. Minerals produced were kaolin and lime for agricultural uses, and experimental peat harvesting for energy applications. The total value of the minerals produced during the year was estimated at $1.1 million .2 In early 1985, an agreement between the Government and Amoco International Oil Co. was ratified for a petroleum exploration concession covering 248,000 hectares of Lake Tanganyika. Onshore exploration in the Ruzizi Plain was already under way the last half of 1985. By yearend, enough seismic information was available that Amoco hoped to complete data analyses, determine onshore drilling sites, and begin drilling operations before the end of 1986. Also to begin in the latter part of 1986 were seismic studies of Lake Tanganyika. Throughout 1985, Amoco officials were negotiating with the Government of Zaire for expanding the exploration acreage into that country's portion of northern Lake Tanganyika and the Ruzizi Plain. An agreement between Amoco and Zaire could have important beneficial economic implications for both Zaire and Burundi, and onshore seismic work in Zaire logistically supported from Bujumburi could begin almost immediately.

Jan 1, 1987

By Norwood B. Melcher

This report describes preliminary experiments by the Federal Bureau of Mines on the practicability of adding raw pellets of taconite concentrate to blast furnace feeds. The usual industrial practice is to harden the pellets by heating before they are charged to the furnace. The Bureau research demonstrated that raw pellets could be successfully smelted in an experimental furnace with no significant change in coke consumption and only a moderate increase in dust losses. The dust loss was 43 pounds per ton of metal for an all-pellet charge, compared with 7 pounds per ton for an all-sinter charge. Raw taconite pellets undergo only slight degradation during charging to the furnace if 1 percent bentonite is used as a binder. INTRODUCTION Fines and concentrates must be consolidated or agglomerated into larger masses before they can be smelted in a commercial blast furnace. Such agglomeration is usually done by sintering, pelletizing, nodulizing, or briquetting. Sintering has been the more common practice, but with the advent of taconite concentrates pelletizing is increasing in importance.

Jan 1, 1960

By Parviz F. Rad

The Bureau of Mines conducted rock-cutting experiments under constant normal force and constant penetration in an effort to correlate laboratory data with those obtained in the field. Both independent and interacting groove spacing regions were studied, and optimum and critical cutter spacings were determined. For the laboratory work, the effects of specific energy, muck weight, groove depth, cutting coefficient, and size distribution of the muck for both independent and interacting grooves were studied. For field operations, forward thrust, torque, advance rate, and muck size distribution were the parameters studied. Satisfactory correlation is obtained between laboratory cutting results and field performance data.

Jan 1, 1974

By C. M. McCulloch

Examination of several coalbeds in Walker County, Ala., Cambria, Greene, and Fayette Counties, Pa., and Raleigh and Wyoming Counties, W. Va., indicates that cleat orientations are similar throughout a vertical sequence of strata. Studies of cleat orientation were carried out in underground mines that are operating in separate coalbeds vertically above one another. The data show that over a vertical separation of 100 to 400 feet, the average difference in coal cleat orientation between mines is 04° for the face and 08° for the butt cleat. Variations of coal cleat direction between coalbeds examined in strip-mined areas show similar values. Cleat orientations measured at outcrops agree well with the directions measured underground, suggesting that the amount of vertical separation between coalbeds has little effect on the resulting differences in cleat directions. The largest variation of cleat directions between adjacent coalbeds occurs where a large horizontal distance separates two sample locations. Cleat orientations for deeper coalbeds are most reliable where the data are taken from directly above.

Jan 1, 1976

By R. C. Wang

Solid-liquid flow in different pipe geometries was investigated. This investigation was conducted by measuring delivered solids concentration and head loss. The delivered solids concentration was measured to study the effect of pipe geometry on the minimum carrying velocity above which solids do not lag behind the fluid. Head loss was measured to study the effect of pipe geometry on the friction loss. A mathematical formula was developed for determination of the minimum carrying velocity. Darcy-Weisbach's equation and Durand's equation were used for comparison of head losses of pipe shapes. Of the different pipe shapes studied, each having the same interior cross-sectional area, the rectangular pipe with the wide side oriented as the base yielded the lowest minimum carrying velocity at high solids concentrations. The minimum head loss at low velocity and high solids concentration also was attained with this pipe. Although the circular section is known to be the best for transporting liquid only, the present study suggested that pipe geometry is a factor in lowering the operating velocity and reducing head loss in solid-liquid flow.

Jan 1, 1973

By Edmund S. Leaver

This information circular is written is response to the marry requests for information on the recovery, or reason for poor recovery, of fine gold by the amalgamation process. Checking Gold Content Experience has shown that in many cases error has been made because the true told content of a particular sample or deposit was not known. Fire assays of representative samples give accurate results and should be considered final in determining the gold content.

Jan 1, 1928