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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 D. B. Gawthrop, A. Taylor, G. St. J. Ferrott

"This paper presents data obtained as part of an investigation of the explosive properties of ammonium nitrate. During the course of the work: it was found desirable to investigate the sensitizing action of nitrostarch in mixtures of ammonium nitrate containing low percentages of this material. Data were derived as to the sensitivity to decomposition by heat and the completeness of detonation and,of detonation of straight ammonium nitrate, as compared with ammonium nitrate-nitrostrarch mixtures containing 1 to 10 per cent of nitrostarch.The ammonium nitrate was a sample of coated material obtained from the salvage of amatol shells. Its analysis was as follows:"

Feb 1, 1930

By Chas. F. Jackson

The annual reports of the supervising engineering of the nine sections comprising the Mining Division are assembled in the following pages and constitute the annual report of the division. In planning activities, the aim is to adapt them to changes in conditions, in the needs of the mining industries, and in the public interest; those current activities that contribute most to problems of present concern are emphasized, investigations of less immediate importance being recessed, if necessary.

Jan 1, 1940

By Chas. F. Jackson

The annual reports of the supervising engineers of the nine sections comprising the Mining Division are assembled in tie following pages and constitute the annual report of the division. In planning activities, the aim is to adapt them to changes in conditions, in the needs of the mining industries, and in the public interest; those current activities that contribute most to problem of present concern are emphasized, investigations of less immediate importance being recessed, if necessary.

Jan 1, 1940

By D. L. Paulson

The Bureau of Mines studied the feasibility of producing copper matte in an electric furnace from blends of copper concentrate similar to those currently smelted in a gas-fired reverberatory system at an installation in Tacoma, Wash. A 800-kva electric-arc furnace was used to determine the distribution of constituents when arseniferous concentrates are being smelted in an electric-arc furnace. Test results from smelting 40 tons of materials indicated that electric smelting is more like a conventional gas-fired system than originally expected. Although gas composition over the molten bath is much different in an electric furnace, the secondary constituents such as arsenic, lead, zinc, and antimony behaved the same as in a reverberatory furnace. The results established that an electric furnace would be compatible with sulfur and particulate recovery facilities that are being used.

Jan 1, 1976

By E. J. Matson

From February until July 1943 the Bureau of Mines conducted an exploration project at the Majuba Hill mine to determine tonnage aria grade of the copper and tin ore and to search for extension of the mineralization. The work comprised sampling, long-hole drilling, underground excavation, and ore-dressing test.

Jan 1, 1948

High resolution seismic refraction tomography has proved to be a useful tool to effectively estimate depth of blast induced damage in a mine face. Excavation blast damage can be as shallow as 1 to 2m and requires resolution at a fraction of a meter for effective imaging. We used an accelerometer with flat frequency response to 1000Hz to record data at spacings of approximately 0.25 to 0.5m along mine walls. First arrival times from the seismic data were used to produce P-wave velocity tomograms. The tomograms show transition from low velocity zones to velocity associated with competent rock. We interpret the low velocity zones to indicate residual fracturing from blasting. Experiments on a concrete test block and at two underground mine locations give results that are consistent with fractured rock transitioning to competent rock. Our method can be applied efficiently in an underground environment to provide continuous velocity information with depth into a mine wall over a span of approximately 10m.

Jan 1, 2009

By Graham W. Marks

This report is the fourth of a series concerning the development of spectrochemical methods for the analysis of ore samples and related Metallurgical materials by the total-energy method. In this report, the application of this method to the determination of thallium is discussed. This element lies in group III of the periodic tale; one other Clement of this group; indium, has already been investigated.

Jan 1, 1949

By R. T. Artz, Simpson. O. V.

"INTRODUCTION The provision of escapeways from coal mines is a moral and, in most States, a legal obligation of mine owners and operators. The obligation is not always fulfilled because of the hope that no occasion will ever arise requiring the use of such facilities, and, as time passes without the need for using them, a false sense of security is born in the belief that ""it can't happen here.""The disastrous fire in a mine in Ohio on July 5, 1944, again focused attention on the importance of escapeways in averting disasters and made it clear that one or more dependable exits must be provided from a mine and parts thereof where men might be trapped by being cut off from the regular travel route. This matter of always-having available travelable exits has been advocated for many years by the United States Bureau of Mines."

Aug 1, 1948

By A. L. Engel

In recent investigations of chloride Volatilization of gold at the Reno Station, it was found that the addition of small amounts of copper and NaCl to the charge brought about improved volatilization of the gold. The investigations described in this report were concerned with the recovery, in an aqueous medium, of fumes from chloride volatilization of gold. It was attempted to discover a suitable aqueous medium that would permit absorption, solution, or precipitation of all the volatilized gold immediately upon contact with the medium. A simple laboratory apparatus was employed to produce fumes by volatilization. To this furnace was attached an absorption train consisting of a series of chambers containing the aqueous medium, through which the fumes were drawn by suction. A satisfactory synthetic ore that contained metallic, gold in a quartz-matrix was made and utilized, enough. gold being present in a' small amount of material to permit an accurate, metallurgical balance of the volatized values' to be obtained in all the experiments.

Jan 1, 1949

By H. W. Kilau

The U.S. Bureau of Mines examined the wettability of bituminous and subbituminous coals before and after exposure to ambient air atmosphere, as part of an ongoing project investigating the coal-wetting abilities of surfactant solutions intended for the suppression of dust during coal mining operations. Exposure periods were generally 7 days or less, and the changes in wetting response were measured with a capillary penetration apparatus. Wetting solutions tested included a nonionic surfactant, two anionic surfactants, and pure distilled water. After exposure, higher ranked bituminous coals treated with nonionic surfactant solution and pure water showed increased wettability, but lower ranked subbituminous coals showed decreased wettability. With the anionic surfactants, the coals demonstrated opposite responses. The wettability changes appeared to be related to the coal moisture content. These changes may be amplified by specific, but incompletely understood, interactions between surfactant polar groups, absorbed water, and the coal surface.

Jan 1, 1989

Argentina follows Venezuela and Mexico as the largest producers of crude petroleum and natural gas in Latin America. Argentina 1S practically self-sufficient in fuels, but relies substantially on imports for its supply of copper, iron ore, ferroalloys, sulfur, and fertilizers. Mining activity is limited and is in an incipient stage of growth, considering the country's potential for mining. Most nonfuel mineral output in 1979 consisted primarily of minerals used for construction, while only 9% are other nonmetallic, and 2% are metallic minerals. Argentina is Latin America's major producer of boron minerals and uranium (yellow cake). Mineral exports consist primarily of borates, uranium concentrates, and of late, some tin. These exports have in the past been shipped mostly to Great Britain. London banks have been involved in arranging financing for St. Joe Minerals Corp. IS planned development of the El Pachon copper deposit (see map), and were being counted upon to also back the development of large copper and manganese projects. The following is a review of Argentine mineral production in 1979: (For 1981, the production of boron minerals is put at 167,000 metric tons and uranium at 300,000 metric tons.)

Jan 1, 1982

By P. L. Woolf

An investigation was conducted to evaluate the use of a formcoke as the total fuel in the Bureau of Mines experimental blast furnace. The formcoke performed very satisfactorily, and comparisons made with a metallurgical coke showed that the performance with the formcoke was somewhat superior under the experimental conditions used.

Jan 1, 1966

By J. E. Zeilinger

This Bureau of Mines report describes the preparation characteristics of the significant coalbeds of Clarion County, Pa. Of the 15 samples collected, 1 was of metallurgical quality as received, 4 could be sufficiently upgraded to provide acceptable products, and the remaining 10 samples could not be upgraded to metallurgical quality because their sulfur contents could not be lowered to meet the standard. For steam or power generation, 1 sample was of low sulfur content as received, 1 sample could be upgraded to low sulfur content, and 10 samples could be upgraded to medium sulfur content. The original sulfur content of the remaining three samples can be appreciably reduced by removal of the sink 1.58 specific gravity material; however, these coals would be classified as medium sulfur coals both before and after removal of the sink material.

Jan 1, 1968

By Bernard J. Steblay

Two instruments have been constructed that extend microseismic data collection and processing capability for Bureau of Mines research in rock burst, coal bounce and outburst, and roof fall monitoring. The first instrument is a 13-channel tape-triggering system. This system allows better utilization of instrumentation tape recorders by collecting data digitally, turning the tape on only when valid data are present, and increasing the dynamic range of the recorder by using digital data. A digital-to-analog converter is used to provide analog output of the recorded digital data. The instrument records a much larger time slice of transient events than do current commercial devices. The second instrument is a microseismic energy measurement device. This device uses recent developments In integrated circuits to overcome the dynamic range and accuracy limitations of previous instruments. The analog signal is converted to a digital one, and then high-speed multiplication techniques are used to square the amplitude value in real time and integrate it.

Jan 1, 1983

By Rogers F. Davis

This publication has been prepared to supply manufacturers and industrial users a listing of mobile diesel-powered equipment and subassemblies approved and certified by the Bureau of Mines for use in noncoal mines. Testing of diesel-powered equipment is one phase of the Bureau's program of health and safety that concerns approval of electrical and diesel equipment designed to prevent explosions, fires, shocks, or toxic hazards in underground mines, when such equipment is used and maintained properly. Manufacturers submit machinery and component parts to the Bureau for study of their design, safety features, and use. Equipment must pass exacting tests and must meet strict requirements established through research and experience and listed in the Bureau's permissible schedules before the Bureau approves it as permissible for safe use in mines.

Jan 1, 1963

By E. C. Perkins

Preliminary experiments are reported utilizing bacteria to leach manganese from a variety of domestic low grade manganiferous materials. In two large leaches manganese extraction ranged from 71.7 to 92.5 percent, and the products analyzed over 48 percent manganese. Nutrient requirements and leaching time experiments were made. The mechanism of leaching is not understood, but is different than the mechanism encountered in the microorganism accelerated leaching of copper in the presence of sulfide minerals.

Jan 1, 1962

By Edwin C. Reeder

This is one of a series of papers dealing with mining methods and costs prepared under the sponsorship of end in cooperation with the United States Bureau of Mines. The mining methods described in this paper are those used in one of the large mines producing fluorspar in the Kentucky-Illinois fluorspar field, located in southern Illinois and western Kentucky on the Ohio River. The occurrence of ore and the methods of wining are similar to those in other mines in the district; therefore information regarding methods and the results obtained should be of interest. Improvements in methods have been made as experience developed the need of them. The trine is situated at Rosiclare, Ill., on the Illinois Central Railroad, and shipments are also made b r barge on the Ohio River.

Jan 1, 1930

By D. R. Tesarik, F. M. Jones, J. B. Seymour, L. A. Martin, T. J. Williams

Determining backfill stress is an important part of evaluating mine safety, whether personnel are working in proximity to backfill or in other areas of the mine where backfill is an integral part of regional support. To assist in determining stress in backfill more accurately, researchers from the Spokane Research Laboratory of the National Institute for Occupational Safety and Health, Placer Dome, Inc. (Turquoise Ridge Mine), Peabody Energy Co. (Foidel Creek Mine), and Hecla Mining Co. (Lucky Friday Mine) used temperature readings recorded by thermistors to correct for the influence of temperature on stress data. These thermistors were positioned in the stems of earth pressure cells installed in backfill. Corrections were then calculated and compared using four different methods: polynomial equations fit to temperature-versus-stress plots before the pressure cells were loaded by overburden, a factor provided by the manufacturer, a theoretically derived factor, and a linear correction factor based on information collected during periods when no mining was taking place. To evaluate the accuracy of these methods, corrected stresses were calculated using each method and results compared to cumulative stresses caused by blasting at one of the mines. Results indicated that only a small percentage of the temperature effect on stress was corrected using the factor from the manufacturer because that factor accounted for only the pressure transducer and not the entire instrument body. Stresses adjusted with a linear correction factor based on information collected during periods when no mining was taking place were the most accurate. Stresses recorded at two other mines were corrected using the theoretical method and the polynomial equations method; the two methods produced similar results. For some time intervals, the results were identical.

Jan 4, 2006

This project, "Analysis of Men, Materials and Supplies Handling Systems in Underground Metal and Nonmetal Mines" documents the productivity and safety aspects of the existing equipment and systems utilized in transporting personnel and supplies from the surface to the underground production work place. The Present Systems Study (this text -Volume II) documents the productivity and safety of existing men and material movement systems for six representative underground metal and nonmetal mines. Identification of common problem areas was performed using recognized industrial engineering techniques. The back-up data for the industrial engineering analysis of each mine is included as respective appendices (Volume III). A summary of the study background material, six mines' problem areas, comparison of problem areas, problem analysis, and solution recommendations are included as the project final report (Volume I), bound under separate cover.

Jan 1, 1975