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Prevent the propagation of a fire and control the spread of smoke and toxic gas in underground mines. Approach A fire door suitable for large openings in underground noncoal mines and providing protection for openings requiring 11/2 hours of fire resistance, a 250°F maximum temperature rise, and high pressure differentials was de-signed, laboratory tested, and in-mine tested. How It Works The door is a double-acting swing type. Its two panels. connected by an overhead linkage, open in opposite directions. Consequently, high pressure differentials across the door have little effect on the force required to open and close the door. The door is constructed of 14-gauge sheet steel skins welded to both sides of a 5-inch-wide steel channel frame. The frame is rein-forced with 5-inch-wide steel channels in a horizontal and diagonal pattern. The voids between the reinforcing members are filled with a ceramic fiber insulation material to limit the surface temperature rise of the unexposed side of the door during a fire. A fire -resistant neoprene-coated fabric is used to seal around the edges of the door panels. The door is opened and closed by an air cylinder, attached to the over-head linkage and operated by lanyards on either side of the door. The door design includes an optional airlock manway for drifts of adequate width.

Jan 1, 1983

By H. G. Lucas

A feeder screw supplied at constant pressure by a hopper-orifice arrangement was developed for feeding solids in size ranges up to several hundred micrometers at constant flow rates. Performance of the feeder was evaluated by measuring the flow rates obtained with 3-to 7-micrometer coal ash, 70 percent through 200-mesh coal, and minus 325-plus 400-mesh coal ash. Constant feed rates within a few percent of set values were achieved for half-hour periods for the larger particles and for 5-minute periods for the finer particles. Suggestions are given for feedstock preparation and feeder operation for optimum performance.

Jan 1, 1974

By Robert H. Schutz

This publication lists and describes devices approved jointly by the Secretary of Interior and the Secretary of Health, Education, and Welfare, under the provisions of [§]70.300-1, Part 70, Subchapter 0 of Chapter I, Title 30, Code of Federal Regulations (35 F.R. 5548, April 3, 1970), for use as respiratory protection against respirable pneumoconiosis-producing dusts. Included are type C supplied-air respirators approved under Bureau of Mines Schedule 19R and dust, fume, and mist respirators approved under Bureau of Mines Schedule 21B.

Jan 1, 1971

A primary objective of the Surface Mining Control and Reclamation Act is to establish uniform national regulatory standards to protect the environment during mining and for reclaiming land after it is disturbed by current and future surface coal mining. In recognition of the wide range of climatic and geologic conditions in coal-producing areas, Congress provided that individual states may establish their own programs for regulating surface and underground coal mining and reclamation on private land. The standards for state programs must be at least as effective as the federal standards. Initial and Permanent Regulatory Programs Congress recognized the importance of establishing regulations to implement the Act as quickly as possible, while recognizing that the preparation of such complex regulations would be a lengthy process. Consequently, a two-phase schedule was established. An abbreviated initial program was put in place immediately, followed by a more extensive and detailed permanent regulatory program. The initial program regulations were published in December 1977, and mine permits issued by states after February 1978 were required to conform with those regulations. Regulatory provisions contained in the initial program included 12 basic performance standards, continuation of existing state permitting, bonding, and enforcement processes (although if those features did not already exist, they did not have to be added), a federal inspection frequency of once every six months, joint state and federal inspection and enforcement in states that had existing programs, and the prohibition of mining in the specific areas listed in the Act. Permanent program regulations were published in March 1979, following extensive review and comment from the public, including the coal industry and organized environmental groups. The regula¬tory provisions in the permanent program expanded those in the interim program by including the implementation of all performance standards contained in SMCRA, a new permitting process, a requirement for performance bonds, an increased inspection frequency (one per month), a new enforcement process, and a process for designating lands unsuitable for surface mining. The regulations for the permanent program have been revised several times since 1979; more revisions can be made as new mining and reclamation tech¬niques are developed. Such changes were anticipated by Congress; in fact, a provision in SMCRA for experimental practices encourages advances in mining and reclamation techniques.

Jan 1, 1992

By C. L. Severy

On the Pacific coast during World War II, a tremendous ship-building industry was developed, Early in the war it became impossible to obtain in- got or steel scrap for ship ballast. Magnetite, an oxide of iron, was sub- stituted as it fulfilled the requirements of weight for available space in the ships. Consequently, a new use for the western magnetite was rapidly developed.

Jan 1, 1948

By G. E. McElroy

[During the period July, 1923, to April, 1924, we made a large number of careful determinations of the resistance to the passage of air in selected sections of airways in the metal mines of Butte, Mont. The experiments were conducted with the cooperation of the Anaconda Copper Mining Co., Frank D. Cannon, mining engineer of that company, and Fred P. Gaethke, mining engineer of the bureau, assisted in carrying out this work. This paper summarizes the, main group of data obtained in the form of a table, of friction factors, or coefficients of friction that is, values of K in the generally accented formula or air flow of [P = KSV or H = KSV2 ] where, in units customary to mining practice;]

Jan 1, 1925

Improve the dust control effectiveness of dry collection systems on surface coal mine drills. Approach Use a dust pelletizer to convert the respirable dust particles discharged by the dry collector into dust pellets that present no health hazard. Background Blasthole drills are well-known sources of respirable dust that can contain significant amounts of quartz. The drills frequently use a dry cyclone-filter type collector that can obtain dust reductions theoretically greater than 95 pct. However, surface mine drills using dry collectors typically have three major dust sources that significantly reduce the overall effectiveness of the collection system: (1) the dust collector dump cycle, (2) drill shroud leakage, and (3) leakage around the drill stem seal in the drill table.

Jan 1, 1989

Develop a method of dewatering ultrafine mineral waste that will increase water recovery from the waste and produce a dewatered material that eliminates the need for large settling ponds. Background In the hydrometallurgical treatment of many ores and concentrates to recover mineral values, slurries of fine particles are generated. Some of these slurries settle slowly and are difficult to dewater. This inherent property causes environmental and handling problems for the minerals industry. Examples of such problem wastes are clay wastes generated during the mining and beneficiation of phosphate ores, the processing of coal to produce a low-ash material, the cleaning of bentonite, beneficiation of potash, and the recovery of mica from clay-containing ores. At the present time these waste slurries are treated by techniques such as impoundment, thickening, and thickening followed by filtration. But factors such as new environmental regulations, the loss of mineral values in the waste slurries, the need to recycle water in the processing facility, and the lack of land suitable for impounding the waste have shown that new technology will be needed in the future to handle waste slurries.

Jan 1, 1986

By Loyal Clarke, H. H. Storch

"The discovery of large deposits of polyhalite (K2S04.MgS04.2CaSO4.2H2O) in Texas has led to an investigation of possible industrial proecsses for the extraction of potash from this material. This mineral was first discovored in small quantities in the European potash deposits in or about the year 1800. Chemists fire thought it to be a form of calcium sulphate, but a more accurate analysis by Strohmiyer indicated the composition as given by the above formula.The decomposition of polytalite by aster is very slow and results in the formation of a layer of gypsum at the surface of the polyhalite which retarts the solution of the potaseium and magnesium sulphates. To obtain a substantial yield of K2S04 in solution it is necessary to use large amounts of water at room temperature, for he concentration of K2S04 is limited by the low solubility of syngonite (K2S04.CaS04.H2O) whereas at 100º C. several days boiling are necessary to obtain more than a 6 per cent K2S04 solution even when finely powdered polyhalite is employed.In 1854 H. Rose discovered that calcination, followed by leaching with water, resulted in a larger extraction of the potassium and magnesium sulphates, as compared with leaching without precalcination. During the course of a series of investigations concerning formation of oceanic salt deposits, Van't Hoff and his pupils obtained sufficient data to construct the equilibrium diagram for the system K+Mg+SO4--Ca++.H2O for 25° C. and for 83° C. These data are very well summarized. in the International Critical Tables' and by Boeke and Eitel. From a consideration of the diagrams for 83º C. one would conclude that an extraction of polyhalite with moderate amounts of water at 33º C. would result in a solution whose maximum concentration of K2So4 would be about 3.6 grams per 100 grams of water and of M2SO; about 4.0 grams per 100 grams of water, corresponding to equilibriumwith the solid phases: Polyhalite potassiam-calcium pentasulphate and anhydrite.The fact that it has been found possible to obtain as high as 11.4 grams of K2S04 per 100 grams of water (see table 6) and an equivalent amount of MgSo4 (8.1 grams per 100 grams of water was obtained corresponding to a ratio K2/Mg of 0.98; indicates that the formation of these complex salts is very slow. To be sure, this results was obtained at 100° C. instead of 83º C. However, the work of Anderson and Nestall 9 on the double salts of calcium and potassium sulphates at 100º C. indicates that the diagram at 100º C. C. would not be greatly different from that at 83º C. This slow rate of approach to equilibrium when combined with precalcination of,of polyhzli-,a is the 17,asis of some of the more p:olisinE methods of extracting potash from polyhalite."

Jun 1, 1930

By F. S. Karn

Measurements were made of the flow of helium, methane, ethane, butane, and toluene through thin disks of coal. All measurements were made on a dense layer in the Pittsburgh seam identified as attritus. Flow increased with pressure differential and temperature. At room temperature and a pressure differential of 1 atmosphere flow rates along the bedding plane of Pittsburgh seam coal were helium 881 X 10-10 cm2 sec-1, methane 1.2 X 10 -10 cm2 sec-1, ethane 0.54 X 10-10 cm 2 sec-1, n-butane 0.35 X 10-10 cm2sec-1, and toluene 3.8 X 10-10 cm2sec-1. Flow rates were 50 percent lower across the bedding plane of the coal than along the bedding plane. Activation energies were 3.9 kcal mole-1 for helium and 13.6 kcal mole-1 for methane, with diffusion measured either along or across the bedding plane.

Jan 1, 1970

Reduce shaft sinking costs and workers exposure to mechanical hazards, drill dust, blast dangers, and fumes. Approach Replace drilling and blasting by using a large, cab-mounted impact breaker suspended from the bottom work deck of the galloway. How It Works The pneumatically actuated impact breaker is positioned by an articulated boom con-trolled from an operators cab. The breaker delivers 2,000 ft-lb blows that fragment the rock at the shaft bottom. Mucking is accomplished by a backhoe bucket on an articulated boom mounted on the cab. See photograph. The mucked material can be removed either by dumping into a previously drilled borehole or by being lifted out in a muck bucket as shown in the drawing. Positioning of the breaker, rotating the cab around its vertical axis, and moving the cab support frame around the perimeter of the shaft are all controlled by one joystick. Separate controls position the mucker boom, which can be swung horizontally through a 180° degree arc towards either side of the cab. Because the cab can be rotated to any position around its vertical axis, and can also be moved in a horizontal circle around the shaft, virtually any position on the bottom of the shaft can be reached by the breaker and mucker.

Jan 1, 1981

By Rudolf E. Greuer, Linneas W. Laage, Xinton Chang

All output is saved in the file MFIRE OUT m the di¬rectory and on the disk containing the program The file can be inspected with a text processor and sent to a print¬er, if needed CONTENTS OF OUTPUT FILE The comment lines, reference temperature, air densi¬ty, a table of the units of measure for the results, and the average values are shown at the beginning of MFIRE OUT All input data will be shown in the output file if LOUT on Control line number 1 is _<-1 For each contamination source, a new branch will automatically be setup The new airway and junction ID numbers will not interfere with the original numbering scheme of the data file Next are the results of the selected simulation(s) in the following order network balancing, network balancing considering temperatures, transient-state modeling, and altered equilibrium due to fire and distribution of the contaminants. Depending upon the contents of the data file, and the simulation selected, attention, warning, and error message will be shown at locations where calculations resulted in unusual conditions

Jan 1, 1990

By A. R. Rule

This report describes preliminary studies by the Bureau of Mines to develop a procedure for extracting the fluorine from low-grade fluorspar ores in which the CaF2 particles are finely locked in the calcite matrix. A combination of flotation beneficiation and pyrohydrolysis is applied to recover and to liberate the fluorine. Flotation of a finely locked high-calcite fluorspar ore containing only 11.7 pct CaF2 recovered over 92 pct of the fluorspar at a grade of 51 to 52 pct CaF2. Pyrohydrolysis of the flotation concentrate liberated nearly 90 pct of the fluorine as aqueous HF. By this procedure over 80 pct of the fluorine contained in the original ore was extracted.

Jan 1, 1974

By Kihong Park

A hygroscopicity tandem differential mobility analyzer (HTDMA) technique is used to determine size-effect of nanoparticles (NaCl, (NH4)2 SO4, KCl, NH4NO3, MgCl2,CaCl2) on their hygro­scopic properties (deliquescence relative humidity (DRH) and hygroscopic growth factor (GF)). The HTDMA system uses a combination of two nano DMAs and two regular DMAs to measure particle size change in a wide dynamic particle size range. Particles are subsequently analyzed with a transmission electron microscopy to investigate the potential effect of particle structure or morphology on the hygroscopic properties. We found that structural properties of NaCl and (NH4)2SO4 particles also play an important role in determination of the DRH and GF and are more pronounced at smaller diameters. Data show that the DRH of NaCl nanoparticles increased from *75% up to *83% RH at 8 nm and that their GF decreased with decreasing size. The extent to which the GF of NaCl nanoparticles decreased with decreasing size was greater than theoretically predicted with the Kelvin correction. The GF of furnace-generated NaCl nano­particles that have pores and aggregate shape was found to be smaller than that of atomizer-generated particles that are close to perfectly cubic. For the case of atomizer-generated (NH4)2SO4 nanoparticles, we observed no signi?cant size-effect on their DRH, and the measured GF agreed well with predicted values using the Kelvin correction. For furnace-generated (NH4)2SO4 nanoparticles, a gradual growth at moder­ate RH without noticeable deliquescence behavior occurred. Their TEM images showed that contrary to atomizer-generated (NH4)2SO4 nanoparticles the fur­nace-generated (NH4)2SO4 nanoparticles are not perfectly spherical and are often aggregates having pores and holes, which may favor holding residual water even in the dried condition. For atomizer-generated KCl, MgCl2, and CaCl2 nanoparticles, we observed no signi?cant size-effects on their DRH and GF for the mobility size as small as 20 nm.

Jan 1, 2008

By R. H. King

A very simple cold-bend test was devised and tested for evaluating thermoplastic jackets used on mine-power-feeder cables. A test sample is bent into a semi-circle whose radius is equal to the minimum bend radius recommended by IPCEA and then cooled to the, desired test temperature (-35°C). While at temperature, the sample is straightened by pulling the cable ends with a winch arrangement. The results show that of the jackets tested, those which cannot withstand the test literally burst when the sample is straightened.

Jan 1, 1978

By J. B. Littlefield

The Greenburg-Smith impinger was developed at the Bureau of Mines in cooperation with the United States Public Health Service in 1922 in the course of an investigation of dust-sampling instruments available at that time. Although it is not used extensively outside of the United States, it is now soused in this country to collect samples for the determination of any dustiness, and most of the information correlating degree of dustiness with physiological effect has been obtained by the impinger method. The chief disadvantages in the use of the regular impinger, especially in mines and other places accessible with difficulty, are its bulk, weight, and power requirements. It requires a source either of electricity or of compressed air, which necessitates connections and extension of existing supply lines to each sampling point; the only alternative is the use of a relatively large pump hand-operated with considerable effort.

Jan 1, 1937

By R. V. Ramani, A. S. C. Owili-eger

Mathematical modeling is a scientific exercise with the objective of developing simplified mathematical statements that relate to one another the same way as the processes that are being modeled. The utility value of the model is dependent on the ability of the model to closely approximate prototype behavior. Development of a perfect model, therefore, is an unrealistic objective because of the simpli¬fying assumptions made in building it. However, for a model to be acceptable for application, its operating characteristics or data generated from it should, within reasonable accuracy, duplicate proto¬performance. The validity and accuracy of a model depends on the mathematical constraints presupposed in model formulation. The final model must be tested for mathematical validity and for closeness of representation of the prototype. Mathematical validity, does not, however, imply that the model is accurate and correct but is prerequisite. Model testing and verification for the steady state model are given in Owili-Eger et al (1973). The unsteady state model has been tested for mathematical validity and found to be correct but has not yet been applied to a field condition for lack of data. However, in the application discussed below, the unsteady state model results are compared with pressure curves reported in literature and also with results from the steady state model. Coal seam characteristics and gas reservoir pressure used in this application are extracted from Kissell (1972). These characteristics are for the Pittsburgh seam, Federal No. 2 Mine, Fairview, West Virginia.

Jan 1, 1974

By Susan B. Bealko

Mining provides a large part of the energy and raw materials that feed this Nation&apos;s economy. Copper pipe, concrete, and window glass serve as well known examples of the reliance on minerals in modern society. Less appreciated, but as important, are the hundreds of mined commodities that are an integral and necessary part of everyday products, ranging from medicines and computers to carpet and paper. Coal is a major portion of the country&apos;s energy mix today, as it will likely continue to be in a future hydrogen-based economy. The domestic mining industry also provides strategic minerals that are important for the Nation&apos;s security. The processes to recover these mineral commodities are among the most demanding and complex in an industrial society, and this inherently dangerous industry has historically had the highest risks of fatality and injury. The mining industry has been undergoing some trying and challenging times because of the recent mine disasters in the coal fields. These events have been alarming in light of the strong and encouraging safety record that has characterized mining in the United States for most of the past decade. While mining communities deal with their grief, mine operators, government regulators, and other safety personnel, set about trying to determine why these fatalities occurred. Subsequently, the mining industry is currently experiencing changes in legislation at an unusually rapid pace. The most recent regulatory changes are the Mine Improvement and New Emergency Response Act of 2006 (MINER Act) and the temporary emergency standard for mine seals. The new mine safety laws call on the nation&apos;s mines to adopt certain procedures and safety technologies immediately, or as soon as they become commercially available. Putting all the provisions in place from these new laws is a major undertaking, and will necessitate strong collaborations and partnerships among mine operators, manufacturers, regulatory and research agencies, labor unions, and community groups. It is against this background that Prevention through Design (PtD) components for the Mining Sector are recommended.

Jan 1, 2008

By A. W. Maynard

Simple chemical spot tests for the identification of major alloying elements in aluminum-base alloys are described. The tests are suitable for use by nontechnical personnel working outside a laboratory. Tests for zinc, copper, manganese, and magnesium employ electrographic sampling methods and sample papers. Use of electrographic sampling in a test for magnesium in aluminum is made possible by using glass fiber filter paper. Differentiations between magnesium and magnesium-silicon alloys of aluminum and between aluminum-base and magnesium-base alloys are made by direct chemical solution tests. Description of a device for obtaining reliable electrographic samples is included. A sequence of testing for identification by alloy groups is given.

Jan 1, 1971

By H. Carroll

An ozone detector was built and evaluated for its applicability in smog-chamber studies. The detection method is based on the reaction of ozone with ethylene and the measurement of resultant chemiluminescence. In the first phase of evaluation, the detector&apos;s response to ozone was studied as a function of several instrument parameters, and optimum conditions were defined for the maximum and most stable responses to ozone. In subsequent evaluations, the method was checked for sensitivity, precision, and interferences and was compared with two alternative methods. Results showed the chemiluminescence method to be acceptably sensitive and precise for smog-chamber studies and superior to the Mast ozone meter and KI (colorimetric 1 percent neutral-potassium iodide method) methods in that it is specific for ozone.

Jan 1, 1972