Search Documents

By A. Z. Dimitroff

An improvised rock-dust disseminator, consisting of a 10-gallon galvanized metal milk can that dispenses rock dust in return air currents by the injection of compressed air has reduced the float dust explosion hazards at the Koehler coal mine, Koehler, N. Mex.

Jan 1, 1965

In connection with tin strategic minerals investigations of the Bureau of Mines and the Geological Survey under authority of the Strategic Materials Act (Public 117, 76th Cong., 1st sess.) a study is being made of tin deposits in the United States in an effort to improve the situation with respect to domestic supplies. These studies include sampling and exploration of some of the larger deposits with the objective of establishing emergency reserves, if possible to do so. Two exploration projects have been completed, and the over-all results obtained are set forth in this progress report. RESOURCES Tin was first discovered on this continent in 100 in the Temescal Mountains of what is now southern California. In the ensuing century, occurrences of tin have been reported in no less than 17 States and Alaska. Although most of these are of scientific interest only, tin-bearing veins and placers in California, Alabama, North and South Carolina, Virginia, South Dakota, Wyoming, Texas, New Mexico, and Alaska have been extensively explored, and largo sums of money have been expended in recurring attempts to exploit them.

Jan 1, 1941

By James R. Aggson

The theoretical relationships that are used to calculate in situ rock stress magnitudes and directions from borehole deformation data obtained during overcoring are based on the assumption that the rock is a linearly elastic material. Strictly speaking, this assumption is not valid in any rock. Thus, investigators using overcoring techniques must either accept various degrees of nonlinearity and the associated inaccuracies or use core testing techniques that address the problem and compensate for elastic nonlinearity. Previously developed test procedures for stress-relief overcores partially correct for nonlinearity. This Bureau of Mines paper describes a test procedure that completely corrects for elastic nonlinearity in stress-relief overcores.

Jan 1, 1977

By Fred N. Kissell

In this report the importance of diffusion in controlling the emission of methane in mines is examined. An in-situ diffusion parameter is defined and calculated for a hypothetical unfractured lump of coal in the Pittsburgh and Pocahontas No. 3 coalbeds. The values obtained are similar to those obtained with lump coal in laboratory experiments.

Jan 1, 1972

Permit visual inspection of underground cavities dam the surface. Approach A closed circuit TV camera and a 35mm still camera are lowered down a borehole, and remotely operated. How It Works A platform holding the cameras, and other equipment is lowered on a graduated cable until the depth of interest is reached. Then a quartz lamp and the TV camera are turned on. The television picture is monitored at the surface and recorded on video tape. Areas of special interest are photographed with a 35mm still camera. These photographs contain more detail than TV images because photographic film is capable of higher resolution than a TV transmission.

Jan 1, 1979

By John C. Machisak

THIS CHAPTER of the Minerals Yearbook relates to employment data and injury experience in the metal, nonmetal, and quarrying industries. Combined statistical data on the mineral industries as a whole can be found in volume Ill. Each industry in the chapter is shown separately, and no attempt has been made to combine and show an overall picture. The voluntary reporting of data on injuries and employment by operators of metal and nonmetal mines and quarries has contributed substantially to the promotion of safety in these industries. Data on injury and employment in the clay mining and milling industry are included for the first time. Table 6 contains data for clay mines only for 1955 and for clay mines and mills for 1956. The clay-mill figures are included with other nonmetallic mills in table 5. The information for norunetallic mills was compiled and published for the first time in the 1955 issue of this report.

Jan 1, 1958

By M. D. Schlesinger

Mercury exists in coal in minute quantities, but the large tonnages of coal consumed could represent relatively large amounts of mercury entering the environment. Limits have now been placed on the emission of mercury, and it is important that reliable analytical methods be available to the chemist. The Bureau of Mines has evaluated analytical techniques used by a number of laboratories; most used vapor phase atomic absorption as the final detection method. Neutron activation was used by some of the laboratories. All of the methods described could be applied, but they require careful manipulation to prevent loss or mercury contamination. In the samples analyzed the mercury content ranged between 0.05±0.01 and 0.4l±0.06 part per million.

Jan 1, 1972

By W. M. Dressel

A simple field test for detecting the presence of germanium in rocks, coals, and flue dust has been developed by the Bureau of Mines. The method consists of dissolving germanium from the samples by either acid or fusion treatment methods, adding a few drops of hematein or phenylfluorone dye, and extracting the resulting colored complex with carbon tetrachloride. INTRODUCTION Germanium is obtained commercially as a byproduct of zinc production, as a coproduct of base-metal refining from germanium-bearing mineral, and as a recovered product from the ash of some coals. The growing use of germanium in the electronics industry has increased demand for this semiconducting metal to the extent that an intensive search for new sources of supply is necessary.

Jan 1, 1962

By Frank E. Chase

Kettlebottoms are columnar masses of rock--the preserved casts of ancient tree stumps--embedded in coal mine roof strata (of which they are a part). Because unsupported kettlebottoms can detach from a mine roof without warning, they are a hazard to miners. The primary objectives of this investigation were (1) to better define and describe kettlebottoms and (2) to evaluate kettlebottom support techniques in terms of safety and effectiveness. A telephone survey of mine operators, interviews with Mine Safety and Health Administration (MSHA) personnel, and underground mine visits were conducted in Pennsylvania, West Virginia, and Kentucky. Information gathered during this investigation indicates that the size and frequency of kettlebottoms in mine roof are dependent upon past geologic events and biological processes active during the deposition of roof sediments. To ensure the safety of mine personnel, all undermined kettlebottoms should be supported. The roof should be bolted next to kettlebottoms less than 3 ft in diameter, close enough to allow a portion of a wood or steel header to be extended beneath each kettlebottom for support. Two bolts and a wood plank or steel strap should be employed to support kettlebottoms over 3 ft in diameter.

Jan 1, 1983

By Jon C. Volkwein

Dust concentrations inside and outside enclosed cabs on several types of mining machinery were measured by the Bureau of Mines. Results indicated that properly enclosed cabs can offer significant dust protection for machine operators. Recommendations for improvements in cab technologies were discussed.

Jan 1, 1979

By Douglas D. Reynolds, Tarek Deeb, Qunli Liu

Landmines are a great threat to military vehicles and their occupants. Mine blasts can completely destroy vehicles and kill all the occupants or disable the vehicle and leave the occupants severely injured. Injuries sustained during a landmine blast come from fragmentation that enters the vehicle through a hull breach, hot gasses expanding through the vehicle, or shock created from the extreme pressure of the blast (Lafrance, L.P. 1998). Mitigating the high acceleration experienced by the occupants during survivable mine blasts is the focus of the research being addressed in this paper. Method The objective of the project reported in this paper was to prove the feasibility that pneumatic seat technologies that employ light-weight, foam-filled, inflatable air bladder seats and seat backs can be used to protect the crews of lightweight combat vehicles against the detrimental and injurious effects of mine blasts. This protection includes reducing the shock energy experienced by seated vehicle crews during mine blast initiation and at vehicle slam-down to below potentially injurious levels. Figure 1 shows a schematic representation of the proposed lightweight, foam-filled, inflatable mine blast attenuating seat. It will consist of specially designed interconnected seat and seat back lightweight, foam-filed, air bladders that are supported by a rigid frame. [ ] Results Air gun tests and finite element analyses were conducted to determine the effectiveness of a light-weight, foam-filled, inflatable air bladder seat shock isolation system in isolating a vehicle occupant from the injurious effects of a mine blast. Figures 2 through 5 show analytical and experimental results associated with a 65.8 kg mass resting on an inflatable air bladder that is exposed to a shock input.

Jan 6, 2006

Enable mine personnel to determine the effectiveness of and to optimize the mine fire stench warning system without resorting to costly trial and error fire drills. Approach The mine fire stench warning system is used by underground metal/nonmetal mines to warn mine workers of a fire or other emergency. Stench is released directly into the mine ventilation and/or compressed air lines, and its repulsive odor warns miners to evacuate the mine or to follow other established emergency procedures. Unfortunately, since most deep metal mines have complex ventilation systems, some areas of the mine may receive nauseatingly high concentrations of stench while other areas, in more remote locations, may receive no warning or greatly delayed warring at best. The Bureau of Mines, through research, endeavored to solve this problem with a computer modeling system designed to calculate the distribution of odorant by the stench warning system.

Jan 1, 1986

Graduate education is an integral part of the Center's research program. The scope of. work and the duration of each research project is calculated, in part, by taking into consideration the needs of the graduate research program and graduate training. Full development of student involvement, as demonstrated by the research practicum which is offered to qualified senior undergraduates at Penn State University and is designed to acquaint them with research methods and techniques and inform them of the opportunities available in this field. and the fulfillment of graduate program requirements are of the utmost concern. The Pennsylvania State University and West Virginia University have accredited mining engineering curricula and rank among the schools with the largest enrollment in this area in the nation. The number of undergraduate students enrolled in mining engineering at Penn State and West Virginia University account for nearly 20%, of the total undergraduate enrollment in this discipline in schools across the United States. The Pennsylvania State University. West Virginia University, Massachusetts Institute of Technology, University of Minnesota, and Michigan Technological University, have granted a total of thirty-five (35) doctorate and masters degrees which can be directly attributed to research conducted in the Center.' Of these graduates, fifteen(15) have found employment in the mineral sector of the economy, i.e., in private industry, with government agencies, and at various universities, worldwide. In addition, a number of those graduating with masters degrees are currently pursuing a doctorate degree.

Aug 31, 1989

By A. W. Henderson

The growing importance of halide metallurgy for preparing high-purity metals has stimulated research to extend halogenation reactions to the direct extraction of metals from low-grade sources. This Bureau of Mines investigation involves a pioneering study of chlorination reactions in the presence of a fluorine donor. Tin slags containing tantalum and columbium and a zircon concentrate containing a relatively high ratio of hafnium to zirconium were studied. Direct chlorination of these materials at 500° C. yields only a 5-percent conversion of tantalum and columbium or zirconium and hafnium to anhydrous chlorides. This investigation showed that small additions of calcium fluoride to the reaction increased the recovery of tantalum and columbium to 95 percent and the recovery of zirconium and hafnium to 27 percent. These results were achieved with ratios of calcium fluoride to mineral or slag of only 0.2. Silica, the major impurity in the materials studied, was found to be converted to silicon tetrafluoride during chlorination in direct proportion to the quantity calcium fluoride added to the charge. However, large additions of calcium fluoride decreased the volatility of the resulting halides of tantalum, zirconium, and hafnium. Smaller amounts of calcium fluoride also favored recovering minor metal constituents in the zircon concentrate (uranium, thorium, and rare earths).

Jan 1, 1962

By S. R. Zimmerley, John Gross

"The investigation discussed in this paper was undertaken to obtain fundamental data on crushing and grinding and has been confined, so far, to work on quartz.The results of crushing or grinding have hitherto been judged entirely by the amount of the various-sized particles produced, based. on sieve sizing for particles above 74 microns in size and on microscopic measurement or elutriation for particles below 74 microns - a method which could give only a general idea of what had been accomplished.There was a distinct need of a ""yardstick"" for the measurement of crushed material. It appeared that no advance in the fundamental investigation of crushing and grinding could be made without a reliable method of surface measurement and that such a measurement would have to be based on some property of the surface of the crushed material.A number of attempts based on various surface actions, such as adsorption and heat of wetting, were made to measure surface on quartz particles, but all gave unsatisfactory results. After some preliminary work it was decided that a dissolution method based on Wenzel's law-- ""the reaction velocity between solids and liquids is proportional to the area. of contact""4 -- would be the most feasible.Early use of the dissolution method had been made for surface measurements5, and lately Dr. Geoffrey Martin and his coworkers in England used the dissolution method to determine surface on quartz. They compared the amount of quartz dissolved from a sample in one hour by a hydrofluoric acid solution, with the amountdissolved from a measured quartz cuboid6,After investigating the solvent power of sodium carbonate, sodium hydroxide, and hydrofluoric acid for quartz, hydrofluoric acid was selected as the most suitable solvent, and a dissolution method was developed which gives very reliable results.During the dissolution of quartz in hydrofluoric acid, the reaction velocity changes for two reasons: there is a change in concentration of solution, and a change of surface of the solid. The amount of quartz dissolved in a definite period of time is therefore not a true measure of surface. If, however, the reaction velocity or rate of dissolution for various periods of time be plotted, a curve will be obtained which, if extrapolated to the zero time ordinate, will give the rate of dissolution before any change of surface or any change in the solvent has taken place, and which is a true index of surface. This rate of dissolution, expressed in percentage of the original sample at the zero time ordinate, is designated herein as the ""Initial Rate"" or as simply ""I. R."""

Jul 1, 1928

By M. O. Renwick, Paul Zinner

"INTRODUCTION In September 1943, the Bureau of Mines conducted a limited program of churn drilling on the Winskell property in the Shullsburg area of Lafayette County, Wis. The work was undertaken as part of a general investigation by the Bureau of the zinc-producing area of southwestern Wisconsin at a time when special effort war being made to increase the production of metals necessary for the war program.Drilling described supplemented a previous drilling program conducted by the Vinegar Hill Zinc Co. The results of both programs encouraged subsequent investigation by the Cuba Mining Co. and eventual development of the Andrews mine.ACKNOWLEDGEMENTSIn its program of investigation 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 such project as soon as praticable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the investigative work, and prepares the final report."

Aug 1, 1947

By R. Hogg, E. Kaya

"The presence of agglomerated particles in airborne dust in coal mines has been confirmed by SEM examination of static samples collected on substrates. In addition, the effect of agglomerated particles on the performance of cascade impactors and cyclone-type personal samplers has been studied. Simple procedures have been developed for evaluating the extent of agglomeration in air-borne dust by comparing the observed size-selectivity of the sampling devices with that expected under idealized conditions. Applications of these techniques in the laboratory and in underground mines are discussed.INTRODUCTIONAirborne dust is invariably present in mine atmospheres. Particle size is a primary factor in determining the behavior of the dust, its effects on miners' health and the effectiveness of dust control measures. Obviously, agglomeration of the dust particles can have important effects on: ""natural"" dust removal processes such as settling• the use of water sprays etc., for dust control• pulmonary deposition characteristicsIn addition, the presence of agglomerates could influence the effective toxicity of the dust. For example, ultrafine particles are often thought to be relatively unimportant in the development of respiratory ailments because of their low deposition efficiency. However, the latter could be substantially increased if such particles were present in larger agglomerates. It is by no means obvious that there should be significant agglomeration of the airborne dust in a mine atmosphere. In fact, calculations based on the classical coagulation theories indicate that, at the kinds of dust concentrations that exist even in what would be regarded as “very dusty"" atmospheres, the coagulation half-time* .should be of the order of weeks or even months. On this basis, agglomeration would be expected to be essentially negligible. On the other hand, laboratory experiments (Polat et al., 1991) have revealed very extensive agglomeration in the airborne dust released during the crushing of individual coal and mineral particles. It is postulated that such agglomeration occurs immediately at the point of dust generation. In other words, many of the fine fragments produced on fracture are never completely separated from their neighbors."

Mar 1, 1992

New Continuous Personal Dust Monitors (CPDM) submitted to NIOSH for approval to sample coal mine dust must accurately measure respirable coal mine dust in mine environments. There are two steps in the process which may be done in any order. The manufacturer is required to submit the results of a comparative underground coal mine dust sampling study, where the candidate CPDM is compared to an approved coal mine dust sampling device (currently the Coal Mine Dust Personal Sampling Unit (CMDPSU)). This testing shall follow the guidelines outlined below and shall demonstrate through weighted regression analysis that the mean coefficient of variation with bias correction is equal to or less than 12.8%. The other step involves laboratory testing to determine the electronic and environmental stability. This testing must be conducted by a private, commercial, academic or other laboratory approved by NIOSH.

Jan 1, 2009

Four actual coal mine waters were used in various phases of the research program. All were from the Sewickley Creek area In Westmoreland County, Pennsylvania. The BCR designations, site locations, and nature of the mine water samples are described briefly in the following paragraphs.

Jan 1, 1971

By R. W. Van Dolah

The feasibility of formulating cap-sensitive slurry explosives for use in underground mines with potentially flammable gas atmospheres was examined. Formulations containing aluminum metal as sensitizer and sodium chloride to reduce incendivity were prepared; some were cap-sensitive and had adequate air-gap. Flaked aluminum metal rather than the atomized type proved to be the more effective sensitizing agent of the formulations tested for incendivity in the large gallery of the Bureau of Mines, some were found to be suitably nonincendive.

Jan 1, 1968