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By John T. Dieckmann

This report documents the work performed and the results obtained in a 2-year development of a Mobile Inert Gas Generator for use in the Bureau of Mines Remote Sealing System for fighting underground coal mine fires. The performance requirements of an inert gas generating system for the Remote Sealing System were clearly established. A thorough review of seven possible system designs meeting these requirements was conducted. An air cooled, distillate oil fired combustion type inert gas generator was selected for further detailed design, hardware fabrication, and performance testing. The Inert Gas Generator constructed under this program has been thoroughly performance tested and has been operated in the field for approximately 200 hours. The system has met or exceeded all important performance requirements. The system was used in the fire fighting efforts at the Bethlehem Mines Corporation Cambria Division Mine 33 fire and contributed to the successful containment of the fire. The system was also employed in the demonstration of entire Remote Mine Sealing System at the Jenney Mine in the fall of 1978. The system is currently avail-able for fighting any future underground coal mine fires.

Jan 1, 1979

By G. R. Palmer

Preliminary studies by the Bureau of Mines were conducted to determine the feasibility of a multiple-compartment, ion-exchange (MCIX) column simulator for examining the effect of multiple-orifice plates in the column. A rectangular, five-orifice, three-compartment, MCIX simulator with a cross-sectional plate area of 0.66 ft2 was used for the investigation. Orifices with open areas of 1, 3, and 5 percent were used with various operating conditions. The study was separated into three separate sections: (1) solution flow effect, (2) fluidization effect, and (3) resin transfer effect. The solution flow and fluidization studies showed that for solution flow rates of about 3 gpm/ft2, a I-percent open area plate functioned best, while at solution flow rates of 9 and 15 gpm/ft2, the best open areas were 3 and 5 percent, respectively.

Jan 1, 1981

By Peter K. Mathison

The U.S. Bureau of Mines has developed a hydrologic monitoring system for in situ leaching operations. This system records and displays flow and pressure information from sensors located in leachant injection and recovery wells. Continuous monitoring of hydrologic conditions is important during leaching operations because hydrologic factors such as aquifer permeability, solution injection rates, injection pressure, and solution recovery rates interact and change over time. This hydrologic monitoring system has been tested in an underground setting at the Cyprus Casa Grande copper mine. The system consists of hardware and computer software components and includes two Bureau-developed software applications. This publication describes the implementation of the hydrologic monitoring system and the software developed at the Bureau in support of in situ leaching research.

Jan 1, 1994

By C. W. JEFFERS

At its annual meeting on March 5, 1928, in Washington, D. C., the Joseph A. Holmes Safety Association gave to the Ford Collieries Co., Curtisville, Pa., a certificate of honor for "having worked 922,628 underground man-shifts from August 14, 1920, to December 31, 1926, producing 5,755,669 short tons of coal without a fatality." This remarkable record certainly deserved recognition. It developed that this company's freedom from fatalities continued until October 2, 1929, hence the full period during which no underground fatalities occurred was from August 14, 1920, to October 2, 1929, or 9 years, 1 month, and 18 days, the total tonnage being over 7,700,000. Table 1, shows the complete safety record of the Ford Collieries Co. since 1920 as given by the officials of the company. The first item in Table 1 shows a remarkable performance. This company since 1920 has mined 15 times more coal per fatal accident than the average pro- duction per fatal accident for the State of Pennsylvania in 1928 (255,257 tons). Excluding the two fatalities (one in 1922 and one in 1929) the severity rate for the same period has been 1.259 per thousand hours worked, a record of which the company may justly be proud. However, including the fatal accidents the rate is 2.407. This compares favorably with an average of 12.4 in 1928 for 66 mines in the National Safety Competition. The Ford Collieries Co. operates three mines located in the vicinity of Curtisville, Allegheny County, Pa. One of these mines, Benjamin No. 1, is idle at the present time. The officials are: A. R. Pollock, general manager, Curtisville, Pa., and C. W. Pollock, assistant general manager in charge of safety and operation.

Sep 1, 1930

By R. E. Coleman

The molecular species occurring at the mineral-reagent interface of the galena-aqueous potassium ethyl xanthate system was studied by developing a technique for using an attenuated reflection method in conjunction with standard infrared spectroscopy procedures. Lead ethyl xanthate was detected from the infrared spectra of all galena surfaces treated in the pH range of 7 to 11. At pH 8.5, lead ethyl xanthate formed as a film chemically bonded to the galena surface. A solvent extraction sampling method was employed with infrared spectroscopy to obtain quantitative data on the lead ethyl xanthate removed from the galena surface. The data showed that between pH 7 and 11 thy quantity of lead ethyl xanthate physically adsorbed decreased as the pH was decreased; in the same pH range, the quantity of free lad ethyl xanthate in the aqueous medium remained constant, and the amount of unreacted xanthate varied.

Jan 1, 1966

By Aldo L. Furno

Sufficient quantities of combustible vapors are released by some sulfurs to produce flammable atmospheres under prolonged storage. Hydrogen sulfide and carbon disulfide appear to be the principal flammable constituents in the vapor space above molten sulfur. If sufficient carbon disulfide is present, ignition of the vapor-air mixtures can occur spontaneously on contact with the heated surfaces found within storage tanks.

Jan 1, 1963

By Thomas M. Barczak

This U.S. Bureau of Mines report examines the causes and consequences of longwall face sloughage. Theoretical relationships were developed to evaluate mechanisms that produce slough age. From these relationships, contributory factors were identified for further analysis in field efforts. A survey identified 12 mine sites with sloughage problems, and these were investigated. From these studies, it was determined that the depth of cover and mining height are the two most significant factors causing sloughage on longwall faces. Coalbed friability and cleat orientation also were found to be significant factors in promoting sloughage. It was concluded that sloughage is primarily a problem in thicker seams or seams with friable coalbeds, and that the problem is more severe as the depth of cover increases. Sloughage also was found to increase as the rate of mining decreased. Observations indicated that face slough age can increase dust generation significantly on longwall faces. Current efforts to control dust generation from longwall sloughage are described.

Jan 1, 2010

By Robert M. Doerr

The purpose of the investigation was to determine the oxidation behavior of selected tungsten-cobalt alloys. Specimens of Wand W-Co containing 0.7, 1.7, 3.4, and 9.7 weight-percent Co were subjected to pure 02 at 1,000° and 1,100° K, and specimens of W-Co containing 29.8 weight-percent Co, at 1,100° K. Reaction kinetics were determined volumetrically. For specimens other than those containing 29.8 percent Co, the reactions proceeded at about a constant rate at either temperature, indicating the formation of a scale of constant protectivity; the reaction rates were essentially independent of the Co concentration. The scales on these alloy specimens consisted principally of WO3 and CoWO4. Specimens of a 29.8 weight-percent Co alloy, consisting primarily of the W6CO7 phase, oxidized with only slight deviations from the parabolic rate law at 1,100° K. The protective scale on these specimens consisted chiefly of Co3O4, CoW04, and W1 8°49; Co3O4 was outermost, and the W18O49 was adjacent to the alloy. The results suggest that the Co-rich outer scale inhibited the inward transport of 0 to an extent sufficient to greatly limit the amount of the nonprotective WO3 formed, so that protective W18O49 formed instead.

Jan 1, 1967

By J. A. Organiscak

The Bureau of Mines recently investigated dust generation and methane liberation during half-and full-web cutting at a double-drum shearer longwall face. This study was conducted to ascertain the health and safety aspects of wider web shearing at longwalls. Results from these underground tests showed that deeper web cutting reduced dust generation and methane liberation per ton of coal mined, while significantly improving shearer production rates. When cutting with the airflow (head-to-tail cut pass) full-web cutting decreased dust generation per ton by 16 pct at the shearer and 6 pct at the tailgate, with an increase in shearer production rate of 72 pct. Methane liberation per short ton also deere~sed by 36 pet at the shearer and 22 pct at the tailgate. Full-web cutting against the airflow (tail-to-head cut pass) decreased dust generation per ton by 41 pct at the shearer and 37 pct at the tail-gate over half-web cutting, with an increase in shearer production rate of 61 pct. Methane liberation per ton also decreased by 35 pct at the shearer and 41 pct at the tailgate. These improvements for full-web cutting are a reflection of improved cutting efficiency (less dust and methane produced from cutting) and less new face area exposed per ton of coal mined (less methane liberated from face per short ton of coal mined).

Jan 1, 1988

By James P. Ulery, Frank E. Chase

Clay veins found in coal mines have caused numerous injuries and fatalities. These structures plague all phases of mining, including entry development, pillar recovery, and panel extraction. Clay veins also increase production costs and may disrupt or halt mining. These detrimental aspects have prompted the Bureau of Mines to investigate the physical characteristics of and roof instability problems associated with clay veins. This was accomplished by observing and mapping clay veins in surface and underground mines. The occurrence and origins of clay veins were also investigated to determine predictive capabilities. The investigators found that clay veins normally occur in more stable, less rapidly subsiding coal basins. Clay veins result when tensile stresses develop fissures which are later infilled. These fissures can be propagated by compactional processes and/or tectonic stresses active during and subsequent to coalification. The Bureau also found that associated faults, fractures, and slicken-side planes commonly parallel clay veins and disrupt the lateral continuity of the immediate and, sometimes, main roof. When clay veins parallel or subparallel the direction of face advance, the roof is segmented into cantilever beams, causing unstable conditions. Consequently, the strata on either side of the clay veins should be bolted and strapped together to form a beam.

Jan 1, 1987

By W. L. Crentz

Before Korea was partitioned along the 38th parallel following World War II, the coal fields of South Korea, with the possible exception of the Samchok area, were not considered important to the industrial needs or Japan or Korea. Much of the demand for electric power in South Korea was met by hydroelectric installations north of the 38th parallel. Following cessation of hostilities between Japan and the' Allied nations in 1945, hydroelectric power continued to flow into South Korea from the north until 1949, when the North Koreans severed the power lines into South Korea, thereby forcing that section of the country to depend almost entirely upon coal to generate electric power.

Jan 1, 1953

By Robert C. Dyni

This U.S. Bureau of Mines (USBM) report summarizes a field demonstration of pneumatic backfilling technologies conducted at the abandoned Hillside Coal and Iron Slope in Vandling, P A. Researchers demonstrated two pneumatic backfilling technologies recently developed under the USBM's Abandoned Mine Reclamation Research Program, the Pneumatic Pipefeeder and the High-Efficiency Ejector. Both systems had previously been evaluated at the USBM's subsidence abatement investigation laboratory near Fairchance, P A. The objective of the demonstration was to fill 100% of the abandoned tunnel with backfill stone to prevent further subsidence. The Pneumatic Pipefeeder was used for 21 days, at a rate of 63 to 124 t/ d (69 to 136 st/d), to fill 88% of the tunnel. The High-Efficiency Ejector was used for 2 days, at a rate of 125 to 132 t/d (138 to 146 st/d) to fill the remaining 12% of the tunnel. The backfill placed by both systems was tightly compacted. The major problem encountered was wear on the polyethylene pipeline from the abrasion of the high-velocity backfill. The use of heavier steel pipe minimized the problem. A cost analysis for the entire project is given.

Jan 1, 2010

Develop a user-friendly computer program that permits those interested in mine health and safety to access and analyze on a personal computer (PC) employment, production, and accident data for U.S. coal and metal-nonmetal mines. This software is being designed with a major focus on flexibility and case of use. The Mine Accident Decision Support System (MADSS) will be available for distribution in mid-1994. Currently, the U.S. Bureau of Mines (USBM) is seeking volunteers willing to pilot test a preliminary version of the software and to provide suggestions for its improvement. Background Since 1975, the Mine Safety and Health Administration (MSHA) has compiled large data bases of information about U.S. mines and the reportable accidents, injuries, and illnesses that have occurred in those mines. Employment and production data arc collected on a quarterly basis from each mine and accident information is collected on an incident -by-incident basis. The USBM has compiled estimated costs for each of these accidents using computer models. All of this information is potentially useful to mine health and safety researchers. However, it has been underutilized because it is stored in large mainframe data bases that arc inaccessible to many users and/or are cumbersome and difficult to use.

Jan 1, 1993

By A. B. Needham

A number of the pegmatites in the southern Black Hills of western South Dakota contain sheet mica; and as the demand increased during World War II the area became an important producer of strategic qualities of mica. During this period of maximum activity, the U. S.. Geological Survey made detailed studies of the geological structural control, the mineralogical associations, and the production Of many pegmatites in the Black Hills. On the basis of results of this study, and at the suggestion of the Geological Survey, several of the pegmatites were examined by the Bureau of Mines, and a few were selected for further investigation. Accordingly, the White Bear, Silver Dollar, Buster Dike, and Hot Shot mines were diamond-core-drilled in 1947. The Hot Shot mine was investigated further by deepening the shaft and crosscutting the pegmatite in 1948. The mica-bearing deposits occur in lenticular intrusions of pegmatite in schists of various mineral composition. Eleven diamond-drill holes, totaling 2,111.4 feet in length, were completed on the four deposits. The shaft on the Hot Shot deposit was deepened 44 feet to the 112-foot level, and crosscuts were driven from the bottom of the shaft to the hanging Wall and foot wall of the pegmatite. This publication briefly describes the location, ownership, and history of the deposits and gives details of the work done by the Bureau of Mines and the Geological Survey.

Jan 1, 1950

By T. E. Gray

This report describes the preparation characteristics of the significant coalbeds in Harrison County, W. Va. It is one in a series of Federal Bureau of Mines reports planned to determine coals suitable for the production of metallurgical coke, either as mined or after beneficiation. Over 6.5 million tons of coal was produced in Harrison County, W. Va., in 1958, of which over 3.7 million tons was cleaned mechanically in seven preparation plants. All of the coal cleaned was from the Pittsburgh bed. It has been estimated that more than 1,816 million tons of coal remains in the county in beds 12 inches or more thick. The Pittsburgh and Redstone beds were selected by the Bureau for a study based on current production rates and estimated minable reserves. Sample locations were selected following a study of the literature, conferences with mining engineers and mining company officials in the field, and examination of the available sites. Six samples were collected from the Pittsburgh bed, and three samples came from the Redstone bed, Float-and-sink tests of the samples collected from the Pittsburgh and Redstone beds showed that neither coal could be upgraded to a metallurgical fuel under the standards set up for this study, even after intensive preparation. Finer crushing of the samples moderately increased the yields and slightly reduced both the ash and the sulfur contents in the 1.30-specific-gravity float fractions. Finer crushing slightly decreased the yields in the 1.58-specific-gravity float fractions, whereas it reduced the sulfur content 0.11 percent for the Redstone sample and 0.46 for the Pittsburgh sample.

Jan 1, 1961

By C. J. Wilhelm, John M. Devine, Ludwig Schmidt

"Steel tanks often corrode rapidly in oil fields where the Gas produced with crude contains an appreciable quantity of hydrogen sulphide. In many instances working tanks have been discarded after only six months of service because of failure induced by corrosion.Aluminum has been used for some time in the fabrication of certain equipment incidental to the handling of oils containing hydrogen sulphide gas in solution, and has exhibited no carious corrosive action. These uses indicated that aluminum tanks,be equally effective in counter- acting hydrogen sulphide corrosion. Consequently, in the spring of 1920, an all-aluminum stock tank of 500 barrels capacity and a ""composite"" tank of equal capacity, having a steel bottom and bottom ring and an aluminum top and top ring, were placed in service on the State-Lassiter lease of the Gulf Production Co, in Crane County, Tex. These tanks were under observation for one year, the toot being sponsored by the Gulf Production Co., the Aluminum Co. of America, and the Parkersburg Rig and Reel Co. The results of this preliminary test sustained the belief that aluminum is highly resistance to hydrogen sulphide gas and likewise indicated the type or grade of aluminum which could be most economically used for lease tankage. However, in this preliminary test the tanks were not subjected to contact with the quantities o highly concentrated brines such as often are associated and produced with crude oil. Therefore, it was suggested by representatives of the aluminum Co. that additional tests be made to include production conditions in large quantities of brine would be handled, for pact experience had shown that aluminum often is susceptible to the corrosive action of brines."

Apr 1, 1931

By K. K. Kelley

The heats of formation of two lead vanadates (Pb2V207 and Pb3V208) and manganese vanadate (MnV206) were determined by hydrochloric acid solution calorimetry, supplementing previous Bureau of Mines measurements of the vanadates of calcium, magnesium} and sodium. Heat and free energy data for 11 vanadates were assembled on a common basis. The stability of comparable vanadates (with respect to the oxides) increases in the following order: Magnesium, manganese, lead, calcium, sodium.

Jan 1, 1963

By R. V. Ramani, R. Bhaskar

"The control of respirable dust in mines has been given paramount importance due to the health and safety implications associated with fine dust. The understanding of the temporal and spatial behavior of dust has been recognized as essential for increasing the efficiencies of the existing control techniques and for developing new control strategies. Mining-related studies in this area are, in general, limited. They are also mostly experimental. Some mathematical and computer analyses have been attempted. In this paper, first a review of the mathematical studies performed in the last three decades in this area is presented. Second, a mathematical model for analyzing dust flow in mines is proposed. The model takes into account a number of factors affecting dust transport. It incorporates varying dust generation source strengths and dispersion, deposition, and coagulation of dust in mine airways. Finally, application areas for the model are discussed. A computer program based on the mathematical model has been developed. The program will output the dust concentration in the mine atmosphere as a function of time and distance from the source. The amount of dust deposited on the sides, roof, and floor of the airway is also determined.IntroductionAn airborne dust cloud is a complex system containing particles of varied size, density, shape and state of aggregation. The behavior of the particles is dependent on a number of complex physical mechanisms, often opposing in nature. The net interaction results in the ambient concentration. This size dependent behavior of particles contrasts with that of gases, an area quite widely studied.The term aerosol is used to describe clouds of microscopic and submicroscopic particles in air such as chemical smoke or particulate matter released from smoke stacks. An aerosol system can be regarded as an arbitrary element of volume filled with gas and suspended particles of possible highly variable physiochemical nature. The parameters that are used to describe an aerosol system include concentration, mass average velocity and particle mass and radius. In characterizing such systems, several assumptions are made. Among these is the assumption that particles are smooth, inert and rigid spheres. Again, for example, when the particles are in transport, the possibility of collision exists. As a result of the collision, the particles may coalesce to form larger particles. The probability of sticking is considered a known quantity (lady, 1970). In this paper, the application of the principles used in aerosol systems is explored for the study of the transport and deposition of fine coal dust in underground mines."

Jun 1, 1988

By Otis E. Perkins

This paper is one of a series being prepared for the United States Bureau of Mines to disseminate technical information retarding the methods used in mining nonmetallic minerals. The cost tabulations represent operating expenditures only and not total costs. It is recognized that publication of total costs might in many instances cause embarrassment to individual operators as well as to the industry as a whole. On the other hand, operating costs are essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue. This paper deals particularly with methods and costs of dredging, classifying materials, and transportation at the plant of the Ross Island Sand & Gravel Co. of Portland, Ore. ACKNOWLEDGMENTS The author wishes to acknowledge the assistance of Harold Blake, general manager of the company, and of A. V. Kramer, cashier in charge of the plant office.

Jan 1, 1933

By J. D. Kalasky, Stephen Krickovic

A degasification experiment was conducted in a Pocahontas No. 3 coalbed mine in Virginia. It involved (1) drilling holes in the coalbed in the out- side headings of a set of five being developed in virgin area, and (2) conducting a methane emission rate study as mining progressed and additional holes were drilled. Degasification from all drill holes except the longest in each of the outside headings and the first three drilled (excluding the in-situ pressure hole), was erratic and inconsequential in methane emission rates. The two longest holes liberated 66 and 79 cfm of methane, which is significant for the coalbed, but such quantity lasted a relatively short time; the first three were uniform but low in methane emission.

Jan 1, 1972