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Provide low-cost fire protection for big bulldozers. Approach A fire protection system, previously used on mobile logging equipment and adapted to surface coal augers, has now been adapted for use on large mining bulldozers. How It Works Heat sensors mounted in the engine compartment and hydraulic hose areas detect the fire, usually before the operator does. This causes the system to automatically discharge A-B-C class dry chemical extinguisher through a fixed piping system. The system can also be manually activated from either the opera-tor's cab or ground level. Location of the principal components of the system are shown in the drawing The heat sensors of the sys-tem consist of bimetallic strip switches which operate at about 10000F temperature. Switch operation results in release of compressed gas from a small storage cylinder. The gas expands to blow the dry chemicals out of the nozzles, in a spray that lasts about 15 seconds. The compressed gas used is usually nitrogen, although carbon dioxide is also used.

Jan 1, 1978

Provide a more efficient method of cooling hot working environments in deep mines than is possible with single stage spray coolers or cooling coil heat exchangers. Approach Pass warm mine air through several stages of horizontally oriented water sprays fed by the chilled water supply of the mine. How It Works This concept extends the capabilities and potential applications of the coolers described in Technology News nos. 71 and 93. In this multi-stage design, hot ventilation air is cooled while passing through horizontal water sprays. Air enters the cooler through a diffuser section which slows the airflow and distributes it evenly across the cooler with a minimum of pressure drop. This ensures uniform exposure of the warm air to the cool water and consequent high thermal efficiencies. In the three-stage cooler shown, cold mine service water is sprayed from the first water stage manifold on the downwind end of the cooler. Slightly warmed water from this spray stage is collected in a sump, pumped and then resprayed through the second stage manifold. The process is repeated again for the third-stage. An overall counterflow heat exchange effect is thus achieved by exposing the hottest incoming air to the warmer, third-stage water spray first and to the coldest, first-stage water spray last. Wave plate eliminators can be employed between stages of water sprays to increase thermal efficiency or at the outlet to minimize the water discharged into the mine ventilation air. Cooled air can then be ducted to hot work spaces or simply released

Jan 1, 1985

By C. A. Herbert

"The Bureau of Mines for a number of years has conducted experiments at its experimental mine near Bruceton, Pennsylvania, on the explosibility of coal dust, with particular reference to dust explosions in coal mines, and the knowledge so rained may well be applied to the handling of coal dust at industrial plants and elsewhere.Powdered coal is coming into use more and more as a fuel, and the dangers incident to its use should be recognized and guarded against, as a number of accidents have occurred in recent years due to ignorance of this danger or to carelessness.Within the past three years two very serious accidents, under almost identical circumstances, have occurred on the surface at two different coal mines in Southeastern Iowa, due in each case to the sudden ignition of a cloud of fine coal dust.The first accident resulted in the burning of six men, three of them fatally; the second burned eleven; three men died as a result of their burns.The mines in the Southeastern part of Iowa, where these two disasters occurred, are operating in a thin coal bed averaging about three feet in thickness, and are worked on the long-wall advancing system similar to that of Northern Illinois.The miners in this section are paid on a screened coal basis; in other words, receive no pay for the fine coal. As a result they use forks in loading the coal into the mine cars, and naturally a considerable quantity of coal is left along the roadways. Subsequently this fine coal, together with the roof rock that is taken down to give sufficient height on the roadways, is loaded into cars and dumped in piles on the surface. This roof rock is a block, oily shale and the contribution of fine coal and oil shale gives ample combustible material to thoroughly burn the rock as it is dumped."

Jul 1, 1923

By Thys B. Johnson

A three-dimensional dynamic programing method is presented for determining the optimal ultimate open pit limit. The method given is based on the block concept and is an extention of the two-dimensional Lerchs-Grossmann approach. The three-dimensional technique presented herein is fast and simple and may be used for an initial open pit evaluation when only limited data are available or as a more refined model when the entire deposit is well delineated. The method is illustrated by simple numerical examples and is also presented in algorithmic form. A computer program was written in Fortran IV which implements the three-dimensional algorithm and some computational aspects are discussed.

Jan 1, 1971

By James R. Means, George Bowser

A new phone system was developed that provides eight full duplex communications channels over a single twisted shielded phone line, with no central switching station or line amplifiers. This system greatly simplifies installation and maintenance over that required with conventional switching systems. The system is based on microprocessor technology and digital frequency synthesis. Frequency division multiplexing is used over a bandwidth of approximately 300 kHz, and a baseband voice channel (compatible with conventional pager phones) is provided as a backup to assure communication if the multiplex features fail. Multiplex operations are controlled over a 30-kHz digital channel. The system is designed to operate with up to 16 km (10 miles) of cable plant and a maximum phone separation of 8 km (5 miles). The digital techniques permit a limited amount of monitoring and control capability to each phone. This consists of two pair of contact inputs or outputs, to be used as desired. These "flags" may be read or controlled by a dispatcher's phone.

By Will H. Coghill

Titanium is a well-known component of bauxite ores, sometimes occurring in sufficient quantity to mace its recovery worth considering. This question has been raised by some of the companies lixiviating bauxite ores. At the East St. Louis plant of the Aluminum Ore Co., a subsidiary of the Aluminum Co. of America, the waste sludge discharged daily contains over 75,000 pounds of Ti02. The sludge is all through 20-mesh, and a large proportion is slime. A supple of the waste was deslimed so that a gravity-concentration test of the "sand" could be made. The Aluminum Ore Co. cooperated in the work and made the chemical determinations In order to anticipate the results of table concentration a series of specific gravity fractions (float-and-sink) was made with heavy liquids. Acetylene tetrabromide was used for a density of 2.95, methylene iodide for 3.33, and thallium formate for 3.78, and the double salt of thallium formate-malonate made the separation at slimed sample appears in Table 1.

Jan 1, 1928

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 H. P. Greenwald, G. E. McElrey

"Part IV.- The Resistance Caused by Right-Angle Bends. IntroductionThis paper deals with the fourth phase of an extensive research on coal-mine ventilation factors. A comprehensive report of the entire work is in course of preparation, but abstracts of the various chapters are being prepared in order to make the major results public as rapidly as possible. Parts I, II and III were issued as Serials Nos. 2621 (July 1924), 2647 (October 1904) and 2671 (March 1925) and dealt with the resistance of unobstructed entries, the resistance due to mine cars and, the resistance of timbered entries respectively.Description of the Tests With the last cutthrough between the two butt entries of the test section in the Experimental Mine open, the air flow was deflected, around two right-angle bends in the same direction, the butt entries being 50 feet center to center and approximately 6 by 9 feet in cross section. Each bend had a dead end opening off of it; that at the first bend was in the direction of flow and that at the second bond was at right angles to the flow. For a primary test condition the inner corner of each bend was trimmed square and the dead ends were closed off with board brattices set flush with the line of the cut-through.The two corners of the first band were, then modified both independently and in conjunction. Various modifications of both bends in conjunction were also tested with rather surprising results as to the effect of conditions at the first bend, upon the pressure losses at the second. To confirm the theory developed to fit these results a series of tests were made to give a direct comparison of the -pressure losses as between two bends with the air flow deflected in the some direction at each and with the air flow deflected in opposite directions. The former is designated ""double"" and the latter a ""reversed"" right-angle bend. This series of tests was conducted, however, on the bends at one of the intermediate cutthroughs at which the flow could be deflected us either direction at the second, bend. Here also the average cross-section was 6 by 9 feet and the bends were 50 feet apart."

Jan 1, 1928

By B. W. Madsen

As part of a program to maintain an adequate supply of minerals and metals to meet national economic and strategic needs, the Bureau of Mines conducted research to determine the diffusion coefficients for ferric ions in synthetic copper leach solutions. Determination of ferric ion diffusion coefficients in typical dump leach solutions is necessary for predicting leaching rates of copper from large-scale leaching operations and for optimizing concentrations of ferric iron in solutions to maximize leaching efficiency. Derivative chronopotentiometry, an electroanalytical technique, was used to determine ferric ion diffusion coefficients. The diffusion coefficient decreased dramatically with increasing concentration of iron in solution. An empirical model was used to relate the ferric ion diffusion coefficient to the total amount of sulfate in solution. Measuring the diffusion coefficient dependence on temperature yielded an activation energy of 5.5 kcal/mole of ferric ion. Activity coefficients of ferric ions as a function of concentration were calculated from diffusion coefficient data.

Jan 1, 1981

Minimize the effects of underground mine conveyor belt fires by developing methods to prevent automatic fire suppression system failures. The Problem Fire protection is achieved by prevention, early detection, and planned fire-fighting response. Automatic fire suppression systems are one form of planned fire-fighting response. When these systems are properly designed, installed, and maintained they can effectively control fires. Conveyor belt fires account for about 20% of underground coal mine fires. Fire protection requirements have been established for underground locations because of potential for start and spread of fire and the restricted personnel egress in a fire situation. Belt conveyor systems arc potentially dangerous because of the high fire incidence rate, high temperatures, dense smoke, toxic gases, and rapid flame-spread rate. While investigating the conveyor fire suppression problem, the Bureau identified automatic fire suppression system reliability as a potentially serious deficiency within the mining industry. Table 1 lists common failure modes fur three Fire suppression system types. This table summarizes findings of Mine Safety and Health Administration electrical inspectors responsible for inspection of belt protection automatic fire suppression systems. Batteries, contact points, control wires, and electric servocontrols are all prone to failure. Figure 1 shows rock-dust-contaminated relay contact points. This condition is dangerous because of the chance of intermittent failures, which might allow systems to pass annual functional testing, yet fail during actual fire emergencies.

Jan 1, 1989

Studies on coal mine drainage sludge densification have led to the following conclusions: 1. Coal mine waters containing iron principally in the ferrous (Fea+) state can be treated by a modification of the commonly practiced lime neutralization process to yield a ferromagnetic sludge. The sludge, presumably composed in large part of a hydrated ferrosoferric oxide (Fe304.xH20), is much denser and faster settling than the ordinary "yellowboy" sludge obtained by lime neutralization and aeration at ambient temperatures. 2. The magnetic sludge preparation technique involves (quantitative) precipitation of iron (largely as Fe(OH)2) by the addition of hydrated lime to a pH of 8.5, separation of the resulting sludge from the aqueous phase, and heating of the sludge concentrate to at least 80 C (176 F), preferably higher, followed by mild aeration. 3. Magnesium, present as Mg2 in most coal mine drainage waters, inhibits the formation of the magnetic sludge. This inhibition can be adequately minimized by keeping the pH below 9.6 during lime addition (thus avoiding the coprecipitation of Mg(OH)2) and by separating the sludge from the bulk of the aqueous phase before the heating step, as indicated in (2) above. 4. Aluminum, commonly present in coal mine drainage waters, also inhibits the formation of the magnetic sludge. This inhibition is of practical significance when the molar ratio of aluminum/total iron is greater than 0.18. Below this value, sludges are still appreciably magnetic, but are bulkier and slower settling than those obtained when aluminum is absent. Unlike magnesium inhibition, aluminum inhibition cannot be minimized by the scheme indicated above, since aluminum precipitates as Al(OH)3 near pH 4 and remains dispersed within the sludge. 5. The limitation on aluminum content is probably the most serious restriction affecting the feasibility of the magnetic sludge process as presently conceived. Nevertheless, a limited review of available water quality data has indicated that, in terms of relative acid and iron loadings, a significant number of major coal mine discharges in the eastern Ohio River basin may be amenable to treatment by a magnetic sludge process. 6. Data from tests on the use of magnetic seeding materials indicate that seeding did not enhance the formation of a magnetic sludge under the experimental conditions employed.

Jan 1, 1971

By Oliver Bowles

"In a previous report of the Bureau of Mines (Serial No. 2080 reference was made to a fatal accident from falling rock in a quarry in Utah, and ways of avoiding such accidents were pointed out. A fatal accident similar to it in some respects recently occurred in a limestone quarry in Maryland. All operators of stone quarries are desirous of reducing accidents to a minimum, and almost without exception they welcome any suggestions having in view the establishment of safer quarry practice. It is believed, therefore, that a brief outline of the cir-cumstances surrounding this later accident may be of practical advantage to quarry-men, as it may serve as a guide to them in so conducting operations that such unfortunate occurrences may be reduced in number.The quarry where the accident occurred is in form a circular pit 500 to 600 feet across an 80 to 100 feet deep. The rock is a dense limestone with the beds dipping at an angle of 35 to 45 degrees from the horizontal. Numerous erosion cavities in the form of pockets or narrow spaces following joint planes are filled with red sand and clay. They are confined largely to the upper 20 or 30 feet of the deposit. Open bedding planes are 4 to 10 feet apart toward the surface, and are spaced at wider intervals toward the base of the quarry. The open bedding planes present smooth uniform rock surfaces that dip steeply into the pit at the northeast side of the quarry opening. These smooth surfaces constitute a source of danger, as they may permit loose material to slide into the pit.In this particular instance a blast had been discharged, throwing down a mass of rock for steam-shovel loading. Three men wore employed thereafter for a period of about two days in cleaning down all loose material that might be dangerous to workmen luring the loading process. A mass of red sand and clay in which several large bowlders were embedded was left on one of these slanting surfaces, for the material seemed to be sufficiently secure to be quite safe. The lower edge of the slanting surface was about 25 feet above the quarry floor. The quarry conditions are illustrated in fig. 1, where (a) represents the quarry floor, (b) the vertical quarry (c) the slanting joint plane surface, and (d) the rock and earth resting on the surface."

Dec 1, 1921

By H. C. Loesche

The problem of signaling to the hoisting engineer from the cage in a shaft mine has been given considerable thought and attention by engineers and mine operators seeking to Increase the safety and efficiency of hoisting. HISTORY R. L. Rutherford,3/ an employee of the Magma Copper Co., Superior Ariz., realizing the need for a simple and practical moving-cage signaling system, began a serious of experiments early in 1937, Available electrical moving-cage signal in operation at this date required that signal wires be installed in the shaft to make a simple, positive signal without wires, the first experiments used the pipe lines in the shaft for carrying the signal current, but these experiments were not successful.

Jan 1, 1945

By BUREAU OF MINES

The Bureau of Mines, in its investigations of respiratory apparatus for use in mines and allied industries; tests equipment that is voluntarily submitted by manufacturers in accordance with published schedules of tests. These tests are designed to insure that the equipment has the minimum requirements for safety in use. Approval certificates are issued for apperatus that meets the bureau's specifications, and the manufacturer is permitted to mark his equiment with a seal showing that it has been approved as "Permissible." A complete list of per- missible self-contained oxygen breathing apparatus, gas masks, and hose masks tested prior to January 1, 1930, was published in Bureau of Mines Information Circular 62309. The present list includes all equipment tested and approved prior to July 1, 1930.

Sep 1, 1930

By John W. Frey

This paper presents one of a series of digests of foreign mining legisla- tion and court decisions which is being prepared in advance of a general report relative to the rights of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the laws of Trinidad has been prepared from the best information available in ashington but is released subject to correction and amplification, if necessary, by the proper American diplomatic and consular officers to whom it is being referred through the courtesy of the Department of State.

Sep 1, 1930

By Raymond B. Ladoo

Talc mining ·in the state of New York was first started about 1876, but important production did not start until 1880, when about 4,000 tons were shipped, In 1883 the production was about 6,000 tons valued at $75,000, or an average of $12.50 per ton, From this date the production gradually inc~eased to a peak of 93,236 tons in 1916, valued at $961,510 or about $10,30 per ton, In 1918 the production declined to 71,167 tons valued at $902,100, or about $12,70 per ton. For ma.ey years New York ,-Jas the largest producer in the United states, but in 1917 and 1918 its output was surpassed by Vennont in tonnage thou[;h not in value. In June, 1920, there were three companies producing talc in the Gouverneur district, st. La,1Tence Co'Ul'lty, and one near Natural Bridge.

Oct 1, 1920

"The Generic Mineral Technology Center on Respirable Dust was established in August 1983, at the request of the Bureau of Mines, to conduct research that affords ""...each miner the opportunity to work underground during the period of (his/her) adult working life without incurring any disability from pneumoconiosis or any other occupational disease"". The Center consists of the Mining and Mineral Resources Research Institutes (MRI) of The Pennsylvania State University (PSU) and West Virginia University (WVU) in association with the MRIs of the Massachusetts Institute of Technology (MIT) and the University of Minnesota (UMN). (FIGURE 34) Michigan Technological University (MTU) is also affiliated with the Center in the area of diesel particulates.The Center brings together experts concerned with particles causing potentially disabling or fatal diseases including pneumoconiosis (""black-lung""), silicosis, and asbestosis. The latter is of deep concern not just to workers in the mineral sector of the economy but also to the general populace. The primary goal of the Center is to reduce the incidence and severity of respirable dust disease through advancing fundamental understanding of all aspects of respirable dust associated with mining and milling, and the interaction of dust and lungs. The research program of the Generic Mineral Technology Center explores these scientific, engineering or medical concerns with the objective of refining existing strategies and developing new respirable dust control techniquesand technology that are consistent with the fundamental dust-lung interaction processes that lead to mine worker disability. The work concentrates on five areas (FIGURE 35):"

Nov 1, 1988

By Dana Reinke, William Wiehagen, Launa Mallett, Charles Vaught, Kathleen M. Kowalski, Michael J. Brnich, Lynn Rethi, Lisa Steiner

Safety and health professionals from all sectors of industry recognize that training is a critical element of an effective safety and health program. A major concern in the mining industry today is how to train the present aging workforce plus the expected influx of new and less experienced miners and mine operators as the cohort of older workers retire. This paper defines the problem, offers a model to structure the inquiry, and presents the key issues a multi-disciplinary team of NIOSH researchers identified, based on an extensive review of the current literature in relevant areas. Issues include differences between cohorts, such as the newer workers (Generation M), and present workers (Boomers) with respect to their physical, social, psychological, and cultural characteristics, their learning styles and work expectations. Specific issues for an aging workforce are discussed. Some preliminary recommendations are offered on the type of training needed.

By J. B. Janus

This Bureau of Mines publication updates a series of reports on the quality of coal purchased under specifications for Government use. Listed are analytical data on the composition and quality of tipple and delivered samples of coal collected during the period July 1975 through September 1976.

Jan 1, 1977

By R. P. Beyer

Low-temperature heat capacities and standard enthalpy of formation of copper difluoride (CuF2) were determined by the Bureau of Mines. The low-temperature heat capacities were determined from 11 to 302 K by adiabatic calorimetry. The enthalpy of formation was determined by HC1 solution calorimetry. The standard values of entropy (S°) and enthalpy of formation (?Hf°) at 298.15 K are l8.65±0.03 cal/deg mole and -129.02±0.29 kcal/mole, respectively.

Jan 1, 1978