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The Technology Transfer Seminar on Mine Communications held on March 21-22, 1973, at the Pittsburgh Mining and Safety Research Center, Bruceton, Pa., presented information about recently developed equipment, instruments, and techniques for use in mine communications systems. All of the basic ideas presented in the fine seminar are operational in the Bureau of Mines Safety Research Mine in Bruceton.

Jan 1, 1974

By d&apos, Kathleen J. Amico

THIS SUAMMARY is shown in Minerals Yearbook volumes I and III of this series on mineral production in the United States, its island possessions, the Canal Zone, and the Commonwealth of Puerto Rico, and on the principal minerals imported into and ex- ported from the United States. The several commodity and area chapters contain further details on production. A summary table comparing world and U.S. mineral production also is included. Mineral production may be measured at any of several stages of extraction and processing. The stage of measurement used in the chapter is normally what is termed "mine output." It usually refers to minerals in the form in which they are first extracted from the ground, but customarily includes for some minerals the product of auxiliary processing operations at or near mines.

Jan 1, 1962

By D. R. Flinn

The Bureau of Mines has studied the electrochemical parameters important to the preparation of coatings of the platinum-group metals. Using molten mixtures of sodium and potassium cyanides in an inert atmosphere, techniques have been developed that permit the preparation of baths for platinum, rhodium, and iridium electrodeposition. Cyclic voltammetric and slow sweep rate linear polarization techniques have been utilized to determine optimum potential and current values for preparation of plating baths and for the electrodeposition of coatings. Techniques are described for the deposition of platinum and rhodium coatings at near 100 percent anode and cathode current efficiencies, and for iridium at approximately 80-percent efficiency. Palladium deposition from these molten cyanide baths remains un-satisfactory. The chemistry of the palladium-containing cyanide bath is discussed. Examples of scanning electron microscope photomicrographs of typical platinum coatings are presented. Techniques are described for the preparation of platinum coatings on large objects.

Jan 1, 1982

By Arthur J. Hudson, Lawrence W. Scott

The performance of RETIMET metal foam as a flame arrester on explosion-proof enclosures was investigated by the U.S. Bureau of Mines both in laboratory tests and at the U.S. Mine Safety and Health Administration's (MSHA's) Approval and Certification Center, Triadelphia, WV. The objective of this research was to develop a permissible pressure vent for use on lightweight, vented, explosion- proof enclosures. In laboratory tests, four grades of RETIMET, a stainless steel foam material, were evaluated: (1) 45 NC-7, (2) 45 NC-13, (3) 80 NC-7, and (4) 80 NC-13. Explosive gas mixtures were prepared by a dynamic flow system. Ignition was by a low-voltage arc. Each grade of RETIMET metal foam successfully arrested the flame front in all methane-air tests. To evaluate RETIMET metal foam on large, commercial size enclosures, a multicompartmented enclosure was designed and tested in MSHA's explosion gallery in Triadelphia, WV. Extensive explosion testing revealed that a minimum vent-area-to-enclosure-volume ratio of 11.33 in2/ft3 is required to keep internal pressure rises below 3 psig. The RETIMET metal foam functioned satisfactorily in all tests as evidenced by the absence of external ignitions.

Jan 1, 1992

By Charles C. Myers, Robert M. Doerr

The apparatus described was developed for determining the kinetics of gas - solid reactions at high temperatures by measuring the volume of gas consumed with respect to time . This apparatus consists essentially of a horizontal precision- bore glass tube connecting a small reaction chamber in a furnace to a large constant - temperature reservoir . A drop of mercury in the tube separates the two sides of the system and serves as an indicator that moves at a speed proportional to the rate of gas consumption . The sensitivity of the apparatus depends inversely on both the density of the gas in the system and the cross - sectional area of the tube ; with a tube having an area of 0.079 cm² , the sensitivity for oxygen at 308 ° K and 0.5 atm is 20 cm/mg . The reproducibility of data with the volumetric apparatus is good .

Jan 1, 1964

By R. V. Ramani, R. Stefanko, G. W. Luxbacher

The Federal Coal Mine Health and Safety Act of 1969 has dictated major changes in mine ventilation with regard to both air quantity and quality. Requirements have also been placed on the ventilation of beltlines, gob and face areas, and air velocities on trolley haulage roads are limited. Escapeways, separate from trolley haulage roads and on an intake split of air, must be maintained continuous to the surface. These and other similar requirements have not only precipitated several modifications to existing ventilation systems but also have greatly increased the complexities of new mine ventilation planning. It is apparent that the use of computers in ventilation system analysis and design is a necessity. SUMMARY Although computer oriented analysis of mine ventilation systems was introduced over two decades ago, it has yet to receive widespread acceptance in the United States. Central to this problem is the fact that, while many computer programs for network analysis have been developed, no attention has been paid to the development of computer input data. Consequently, without this foundation, program applications have been infrequent. This thesis has directly attacked this problem and has presented all pertinent information basic to the development of good computer input data. The areas that were covered include quantity measurement, pressure measurement, fan testing, survey data balancing, and the development of a network schematic from the ventilation survey results. These discussions on data collection and the corresponding reduction to computer coding have been illustrated by an application of a ventilation simulation program to an existing mine in Southwestern Pennsylvania. The use of a ventilation

Jan 1, 1977

By Gary P. Sames

Shale roof deterioration in coal mines. caused by ventilation air humidity fluctuations, is a common ground control problem. Shale roof deterioration often results in increased accidents, decreased production, inadequate ventilation, and increasing operating costs in maintaining haulage roads and airways. The results of Bureau of Mines research indicate that air tempering entries are an effective method of controlling deterioration prone shales. Some of the conclusions and recommendations drawn from Bureau research include (1) moisture sensitive shales will react adversely to moisture gains and losses, (2) the majority effect of specific humidity fluctuations can be concentrated in and absorbed by tempering entries, (3) tempering entry panels should be located as near to the main intake as possible, (4) tempering panels should be designed for a conservative recovery and provide a minimum of 20-to 30-min air residence time, (5) ventilation and escapeway requirements must be considered early in panel design, and (6) an efficient support and sealant plan can increase the life expectancy of a tempering panel.

Jan 1, 1985

"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 Joseph Grumer

In addition to nine powder and gaseous extinguishants of propagating Pittsburgh seam coal dust-air explosions earlier evaluated,6 10 other powders have similarly been evaluated under like conditions such that wall quenching of the coal dust-air flames was virtually absent and the dust concentration was temporally and spatially uniform to within about ±5 percent. None of the newly examined extinguishants was better than Purple-K (potassium bicarbonate); the 10 of this report are anhydrite (calcium sulfate), monobasic (4 types) and dibasic ammonium phosphate, natural and synthetic cryolite (sodium fluoalumi-nate), sodium sulfate, and tricalcium phosphate. Except for anhydrite, sodium sulfate, tricalcium phosphate, and the cryolites, these materials were about equally effective, when present in relatively low concentrations (weight-percent of the coal dust-extinguishant mixture). The maximum oxygen concentration for the extinguishment of otherwise uninhibited coal dust explosions and the influence of coal dust particle size and the volatile content of the coal were also explored. For the present, the choice of the inhibitor among the good ones evaluated is not as critical as the system to be used to deploy the extinguishant against a coal dust explosion.

Jan 1, 1973

By Jim F. Lemons

The Bureau of Mines Minerals Availability System collected and analyzed data for 34 nonlaterite and 9 nickeliferous laterite domestic chromite deposits in order to assess their viability as sources of chromium under present technologic and economic conditions. These 43 deposits, none currently in production, contain approximately 6.3 and 22.3 million metric tons of Cr203 at the demonstrated and identified resource levels, respectively. Approximately 4.6 and 15.6 million metric tons of Cr203 are recoverable at the demonstrated and identified levels, respectively, for the 34 nonlaterite deposits. None of these resources are economically recoverable at January 1981 market prices. Production of metallurgical-grade chromite (market price $128 to $144) would require a minimum chromite market price of $237 per metric ton. Chemical-grade chromite production (market price $74 to $85) would require a chromite market price in excess of $188 per metric ton. From the 34 nonlaterite deposits, roughly 5.4 and 17.6 million metric tons of ferrochrome could be produced at the demonstrated and identified resource levels, respectively; however, a minimum market price of $770 per metric ton of ferrochrome would be required to stimulate production. The nine nickeliferous laterite deposits were not evaluated through production stages because of uncertainties in process technology and cost.

Jan 1, 1982

By Edward D. Thimons

The Bureau of Mines developed a stopping design that allows the stopping to be blown down by strong blast forces without incurring any permanent damage. Trials with the new stopping, dubbed the quick-fix blowout stopping, have been conducted in the Bureau's Safety Research Coal Mine at Bruceton, Pa., and in two New Mexico uranium mines. Results have been favorable in all cases. Compared with conventional brattice stoppings or wood bulkheads, the quick-fix blowout stopping is easier and less time consuming to install, is easier to maintain, and in most cases is just as efficient an air barrier. There is same indication that the shape of the stopping makes it more resistant to blast fore s than the fabric stoppings now in use.

Jan 1, 1976

By Gerald W. Elger

This report describes development of the fusion-leach crystallization precipitation process for producing a hafnium content feed material for hafnium-zirconium separation plants. Mixtures of zircon, potassium silicofluoride, and potassium carbonate (or potassium chloride) were fused to prepare soluble potassium zirconium hexafluoride-potassium hafnium hexafluoride salts. High extraction of these salts was obtained by countercurrent leaching the fused material in dilute hydrofluoric acid. About one-half of the hafnium was recovered in hafnium-enriched mother liquor by cooling clarified lead: liquor to crystallize most of the zirconium salt. Additional hafnium was recovered from the primary crystals in a multiple dissolution-recrystallization step. Hafnium-enriched oxides having a hafnium-zirconium ratio of more than three times that of zircon were precipitated from the combined mother liquors. The hafnium and zirconium recoveries in the precipitate were 83 and 24 percent, respectively. About 71 percent of the zirconium and the remainder of the hafnium were recovered in potassium zirconium hexafluoride crystals of low-hafnium content.

Jan 1, 1966

By E. Wittenau

This paper describing the concentrator practice of the Copper Queen Branch of the Phelps Dodge Corporation at Bisbee, Ariz., is one of a series of papers on milling methods and costs being prepared by the United States Bureau of Mines. The Copper Queen Concentrator treats 4,000 tons of copper ore daily by preferential flotation, whereby the copper sulphides are floated and considerable iron pyrite is depressed. During 1929 the heads to the concentrator averaged 2.15 per pent of copper, the recovery was 91.32 per cent of the total copper, and the concentrates produced contained 12.92 per cent of copper.

Jan 1, 1931

By Glenn C. Reed

"Preliminary examination of the Glass Buttes mercury deposits, Lake County, Oregon, was made in August 1945 at the request of W. S. Lazier, present lessee of the deposit.Most of the prospect openings in the area were inspected. The more significant workings were sampled and napped in detail. This report presents the data obtained from the investigation to date.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. noon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. P. S. Dean, assistant director.Special acknowledgment is due to S. H. Lorain, chief, Albany Division, Mining Branch and to S. R. Zimmerley, chief, Salt Lake City, Utah, Metallurgical Division, for analyses of the ores.The presence of quicksilver in the Glass Buttes district has been known since about 1930. The area immediately north of Middle Butte has been superficially prospected by numerous test pits, trenches, shafts, and short adits, which revealed a number of opalized zones. Many of these opalized zones contain weak to strong concentrations of cinnabar. The area has not boon explored thoroughly; no mercury has been produced from any of its deposits.A block of 48 full-size claims has been located to cover a large part of the area in sections 34 and 3, Tps. 23 and 24 S.,R. 23 E.,W.M. These claims, held by, location are owned by H. S. Miller, lumberman of Bend, Ore. W. S. Lazier, 10N. W. 20th Avenue, Portland, Ore., currently controls the property under,a nominal leasing agreement. J. W. McDaniel, 44 Lake Place, Bend, Ore., has done much of the underground and surface exploration on the property.The Glass Buttes district is an area of low relief in the Deschutes River drainage system near the northeast corner of Lake County, Ore. (See fig. 1.) The arid climate is marked by extremes of winter and summer temperature. Water for cane use is not available in the immediate area. Well water, however, can be obtained in limited supply on ranch property 5 miles to the south."

Aug 1, 1946

By Jr. Kauffman

The data contained in this report were obtained incidental to the Bureau of Mine's investigation of the lime-soda sinter process as applied to the recovery of alumina from siliceous bauxite, kaolin, and other high aluminous materials. The Bureau of Mines was charged by Congress to investigate processes for the production of aluminum from domestic low-grade ores. The Eastern Experiment Station at College Park, Md., conducted laboratory and pilot-plant investigations of the recover-y of alumina by the lime-soda sinter process. Reports by the College Park staff covering the recovery of alumina from these sources have been published. The lime-soda sinter process involves the sintering of the finely ground siliceous bauxite or clay with limestone and soda ash in a rotary kiln. During the sintering the alumina supposedly reacts with the soda ash to form soluble sodium aluminate and the silica combines with the lime to form the insoluble orthosilicate. In the early stages of the investigation it was considered desirable to know the temperatures at which the phase changes occurred during the sintering operation. The total time involved in the passage of any given portion of the charge through the kiln was 28 minutes. The exposure time of the charge to temperatures above 600° C. (decomposition temperature of kaolinite) was, roughly, half the total. The exposure to the full temperature of the kiln, 1,100° C was only 3 minutes. (Subsequently, the maximum kiln temperature and retention time were increased.)

Jan 1, 1949

By M. J. Sapko

The U.S. Bureau of Mines has developed a portable meter for measuring the component concentrations in binary dust mixtures whose constituents have different optical reflectivities. The meter has been successfully tested with coal dust-rock dust mixtures taken from coal mines in Europe and the United States and fluorinated-carbon mixtures that change from carbon black to pure white during fluorination. Additional study has also substantiated the theoretical expressions used in the design of the meter.

Jan 1, 2010

By R. H. Jefferson

An electrochemical method to selectively determine sulfur dioxide in the presence of sulfur trioxide was investigated. A hydrophobic gas-permeable membrane separates the gas sample solution from an internal filling solution containing a fixed quantity of chloride ion and a sufficiently large excess of sodium bisulfite so that its concentration may be considered constant. Sulfur dioxide diffuses through the membrane to dissolve in the internal filling solution and liberates an equivalent quantity of hydrogen ions. The electromotive force between a precision-ground, flat-ended pH electrode, which acts as the sensing element, and a chloride sensing electrode, which acts as the reference element, gives a direct measure of S02 in the gas sample solution. Calibration curves in water, tetrachloromercurate (TCM) , and citrate buffer absorption solutions were closely parallel with slopes in their linear segments, ranging from 57 to 52 mv/decade of S02 concentration. The slopes compare reasonably well with the theoretically expected slope of 58 millivolts at 21° C. The water standard curve was linear with respect to the logarithm of S02 concentration from 1 to 1,000 ppm S02; the TCM standard curve was linear from 10 to 2,000 ppm S02; and the citrate standard curve was linear from 30 to 5,000 ppm S02' The high efficiency and nontoxicity of citrate favor it as a substitute for the conventionally used TCM in the absorption solution.

Jan 1, 1976

By J. S. Walker

The Bureau of Mines monitored surface subsidence and water level fluctuations in 10 shallow observation wells above a series of four adjacent longwall panels in southwestern Pennsylvania, for about 4 yr. This study attempted to correlate the changes in the water levels within the observation wells to the measured vertical and horizontal ground movements associated with subsidence. Results of this study indicate that the fluctuation of the water levels appears to be a function of the well location relative to the mine layout and the proximity of mining. Wells are generally unaffected by mining of a preceding panel unless they are located within the angle of draw for that panel. Wells located at the centerline of a longwall panel exhibit the greatest fluctuation and head loss. This relationship may be related to the strain developed by the advancing longwall face. The water levels in the wells monitored fell at the greatest rate when the ground surrounding the well was in tension. The rate of the decline decreased as the dynamic development of the strains was changing from tension to compression. The water levels were found to be near the premining level before the ground was subject to maximum compressive strain. Nine of the ten wells investigated recovered to their premining water level after mining was completed.

Jan 1, 1988

By Shirley F. Colby

A continued rise in construction activity in 1941 forecasts further increases in the demand for building materials of mineral origin, Recent studies by the Bureau of Mines, United States Department of the Interior, reveal that sales of mine and quarry products and their derivatives as a class have followed the long-term trend of construction activity in the past and are benefiting now by the upswing in all types of building. At present most building materials of mineral origin are holding their own in the competitive arena. A few are slipping behind, but others have forged fax ahead. Prominent among those that have surpassed general construction activity since 1925 are sand, gravel, and crushed stone (used in concrete and road metal and railroad ballast) and cement. Both building stone and roofing slate have followed the building curve closely, although in the last few years sales of roofing slate have risen above the curve and sales of building stone have dropped below it. Clay products and building lime, on the other hand, have lagged behind the general procession. Gypsum sales likewise dropped behind, but during the last few years, this industry, thanks to the wider acceptance of its newer products, has staged a marked recovery so that it now stands in about the same relation to total construction activity as it did is 1927-25.

Jan 1, 1941

By J. B. Gayle

The removal of coal particles from a slurry by flotation is made possible by the formation of stable aggregates with air bubbles of suitable sizes. The formation of such aggregates is theoretically possible only for certain favorable combinations of the solid-liquid-gas interfacial tensions. Because interfacial tensions involving solid phases are not conveniently measurable, a related variable, the contact angle, frequently is used as a measure of the floatability of various materials. Zero angles indicate nonfloatable substances, and large angles indicate substances having a high degree of floatability. During a study of contact angles for coal and substances related to coal in their similarity of response to various physical and chemical treatments, particularly flotation, carbonization, and oxidation, the reproducibility of replicate determinations taken within a 4-hour period was found to be much better than that for comparable results taken over a longer period of time. Consideration of possible causes for these differences led to an investigation of the effects of temperature variations on contact angles. References to literature revealed only a small amount of information, some of it apparently conflicting. Specifically, Sutherland and Wark4/ found that temperature variations "within limits" did not appreciably influence the angles measured for galena conditioned with potassium ethyl xanthate. On the other hand, McGlashan and McLeod5/ presented preliminary data showing that for sphalerite conditioned with potassium ethyl xanthate the angle is maximum at 25° to 35° C., depending on the pH of the system.

Jan 1, 1960