Search Documents

By A. A. Sonnek

A simple, portable helium analyzer was developed primarily for field use. Its utility lies in making preliminary surveys before exact analyses are required. The analyzer is based upon chromatographic principles; that is, separation of gas mixtures resulting from variable retention times of the components with respect to a separation medium (column-packing material). It uses thermistors for sensing detectors, a dry battery as source of power, and a micro-ammeter for indicating helium concentration. The absolute accuracy of the instrument depends upon the recency and care with which the instrument is calibrated with a standard gas. The unknown gas should be analyzed immediately after calibration, and another calibration should be made before another unknown sample is analyzed. The instrument is simple to operate, requiring approximately 15 minutes, after calibration, to determine the helium content of a natural gas sample. Although developed primarily for helium determination, the analyzer possibly can be used for other analyses that can be performed at ambient temperatures.

Jan 1, 1965

By J. J. Drost

This Bureau of Mines investigation studied the effect of thermal treatments upon concentratability of a western Mesabi Range nonmagnetic taconite ore and is a sequel to Bureau of Mines RI 7567. Magnetic tube tests were used to develop the data needed to calculate separation efficiency, the primary measure of concentratability. A horizontal tube furnace was employed to heat treat and reduce the hematitic ore samples. The two variables studied were roasting temperature and cooling method. The manner of cooling, either by slow cooling or quenching in water, produced no significant difference in concentratability. Roasting temperatures employed ranged from 500° to 1,000° C, and a temperature of 650° C effected the best concentratability. The temperature of 650° C correlated with the most effective roasting temperature for grindability.

Jan 1, 1973

"There is considerable evidence that all mine dusts do not present the same health hazard. Rank of coal and composition, especially silica content of the mine dust, shape, and surface charge are risk factors that affect the incidence and severity of CWP. Current efforts of Center researchers involve characterization of:•,size/shape/composition•,surface and functional groups•,particle interactions.Work is underway to prepare and characterize respirable coal dust samples, and to develop and evaluate techniques and procedures for the characterization of respirable dust. A suite of standard samples including anthracite, medium volatile and high volatile bituminous coals, quartz, clay, and rock dust have been prepared and thoroughly characterized with respect to the distributions of particle size and compositions. A comparison of the morphology of the standard dust particles with similar particles collected in an underground coal mine is given in Figure 43. Samples of these characterized (Standard) dusts have been distributed among various research groups associated with the Center.The aerodynamic diameter of a particle is a particularly important characteristic since this parameter determines the point of deposition in the human respiratory tract. A 3-dimensional numerical model for theoretically determining the equivalent aerodynamic diameter of irregular shaped particles has been developed and used to analyze coal dust particles and a particle shadowing technique has been developed for .experimental 3-dimensional shape analysis (Figure 44). In the theoretical technique, the equivalent aerodynamic diameter of the particle is numerically determined from computation of the fluid drag on the particle. This allows the aerodynamic diameter of any regular or irregular shaped particle to be determined as a function of the particle's orientation or as an average over all particle orientations. The technique is quite accurate in that the aerodynamic diameter of several coal dust particles have been numerically determined to be within 5% of experimentally measured values."

Nov 1, 1988

By James S. Browning

Domestic production of lithium minerals, source of the lightest metallic element, has increased from an average of 1,327 short tons of concentrate in the 1935-39 period to approximately 37,830 short tons in 1954. This rather phenomenal growth in production and use reflects growing industrial interest in the metal and its salts. This information circular has been prepared to summarize for the casual technical reader the reserve, mining, processing, and consumption situation pertaining to the mineral spodumene - the principal source of lithium. A relatively complete bibliography is included for those who may need more detailed information.

Jan 1, 1958

By Harry Perry, Mary S. Esfandiary

This is a revision of a directory of coal research organizations throughout the world that was first published in 1961 as Bureau of Mines Information Circular 8008. Because of the wide acceptance of the first edition , a revision which would supply up- to - date information on coal research and which would facilitate communication among organizations of similar interest seemed important . This compilation includes the names and activities of organizations of various types -government , university , private , and industry . The areas of investigation that each organization is engaged in are indicated in broad terms : Analysis and constitution , mining and geology , preparation , briquetting , combustion , high- and low-temperature carbonization , gasification , conversion to solid and liquid fuels , and health and safety . Publications issued by and describing the work of each organization are cited ; almost all of the organizations also publish results of their investigations in the technical press . Selected technical and trade publications that publish information on the science and technology of coal and are not published directly by any of the organizations listed are cited in the pages following the list of organizations in each country . Information that would improve coverage and accuracy of the next revision of the publication will be welcomed by the Bureau of Mines .

Jan 1, 1966

By Raja V. Rarnani, Robert L. Frantz

"The Generic Mineral Technology Center for Respirable Dust (GTCRD) was created at The Pennsylvania State University and West Virginia University by a congressional initiative in 1983 responding to recommendations in the 1980 National Academy of Sciences study on the Measurement and Control of Dust in Mines. Many of these recommendations dealt with the need to initiate focused fundamental research for further professional progress in dust control. Long-term, sustained support was emphasized to develop expertise in respirable dust research. In creating this Center, Penn State and West Virginia University were specifically recognized for their expertise in and facilities for research on coal mining and medicine. Today, the Center includes the Massachusetts Institute of Technology, the University of Minnesota, and the Michigan Technology University. The Respirable Dust Center is the only organization that coordinates and integrates the medical, scientific, and engineering aspects of respirable dust disease. The Center works with the U.S. Bureau of Mines (USBM), Mine Safety and Health Administration (MSHA), the National Institute for Occupational Safety and Health (NIOSH), the United Mine Workers of America (UMWA), and the U.S. coal industry in defining the research priorities for the programs of the Center to enhance research synergism.The Center's mission is to enhance the health, safety and productivity of miners by advancing the fundamental understanding of all aspects of respirable dust associated with mining and milling and the interaction of dust and lungs to reduce the incidence and severity of respirable dust disease.All Dust Center activities are focused to be responsive to this mission, which is shared by the several federal agencies closely associated with the GTCRD. While significant progress has made mine atmospheres cleaner and healthier, respirable dust-related disease remains the nation's most pernicious industrial hazard.The goals of the GTCRD were formulated with recognition of the diverse scientific, engineering, and medical aspects of respirable dust, in addition to a need to enhance researcher interaction, as well as education and technology transfer efforts, in the respirable dust area. These goals reflect the needs of the mining industry as determined by the National Academy of Sciences Committee on Measurement and Control of Respirable Dust study done in 1980. The report of this committee encouraged the Bureau of Mines to redirect its research efforts ""...toward obtaining fundamental understanding of the origin, transport and characteristics of respirable coal mine dust."" The GTCRD's goals, detailed in chapter three of this document, were formulated to mesh with NAS recommendations."

Jan 1, 1995

By Donald W. Mitchell, John Nagy, Edwin M. Murphy

To increase safety and productivity in mining , the potential uses and hazards of rigid foam were investigated by the Bureau of Mines Experimental Coal Mine . This research resulted in the development of chemical formulations , spraying equipment , and application procedures that permit safe and effective use of urethane foams for improving mine ventilation , for reducing weathering of mine rock and steel , for constructing seals in fire areas , and for thermal insulation .

Jan 1, 1964

By F. S. Crawford

It has been said that safety promotion passes through four stages--the band-playing, the machine-guarding, the protective equipment, and finally the educational stage; the last is the most important in the development of the safety program. It has been estimated that only 15 percent of accidents can be pre- vented by machine guarding and protective equipment; the other 85 percent must be stopped by the safety efforts of the individual workers and their supervisory officials, and one of the fundamentals of safety work is the education of workers to develop safety consciousness or safety mindedness. One way of educating men to think about safety is by the use of posters. Safety engineers at the Calumet 2 Hecla mines in Michigan have been conduct- ing a safety contest among the men by the use of posters of an unusual type in addition to those usually employed to illustrate bad practices and to display the number of days without a lost-time accident. The first requisite for the success of the safety poster is a good artist or draftsman; in the poster contest instituted at the Calumet & Hecla mines two sheets were prepared illustrating various conditions in the slope workings, including a large number of unsafe practices. The object of the contest was to get the men to think about safety through criticism of the unsafe conditions displayed on the posters. The following notice accom- panied the posters:

Feb 1, 1935

Although the Stamler feeder/breaker has been used for coal crushing in underground mines for many years, it has only recently been applied to other crushing operations. Two companies presently using Stamler feeder/breakers for rock crushing were contacted regarding their experiences with the units in actual field use. In both cases information was obtained directly from the individuals responsible for field operation and maintenance of the units. White Pine Copper Co. has been using Stamler feeder/breakers for over two years to crush copper ore. They now have fourteen 450-ton-per-hour units on line. The ore has a compressive strength of from 18,000 to 28,000 psi and is extremely abrasive. Maintenance is performed on a tonnage basis. The breaker shaft is replaced every 250,000 tons (requiring about 4 hrs) and picks are replaced about every 1500 tons by the operator (requiring about 2 min per pick). Very little unscheduled maintenance has been required. Crushing costs are fairly high (estimated at 13 to 15t per ton including maintenance and operation) because of tale extreme abrasiveness of the material. A new Stamler feeder/breaker with Ultramet wear surfaces was put or line in June 1976. Ultramet was found to increase the life of belt transfer station surfaces by up to 400 percent and it is hoped that it will do the same for the feeder/breaker. At this time it is still too early to evaluate the performance of the Ultramet unit. If it does improve abrasion resistance, crushing costs could be greatly reduced. White Pine is very pleased with the units and the service provided by Stamler.

Jan 1, 1976

By Charles W. Huggins

Electron diffraction and electron microscopy were used to determine the unit cell parameters of garnierite [(Ni,Mg)3 Si2O5 (OH)4] and to examine its crystal habit. Bundles of ribbons, many less than 200 A. in cross section, make up the bulk specimen of the garnierite Electron diffraction revealed the unit cell to be monoclinic. Unit cell parameters were: a, 5.33 A,; b, 9.23 A.; c, 14.96 A.; and ß, 94°441.

Jan 1, 1961

By Clarence O. Babcock

Model pillars of limestone, marble, sandstone, and granite having length to diameter ratios of 3:1, 2:1, 1:1, and 0.5:1 were broken in axial compression to determine whether lateral end constraint affected the breaking strength. Steel rings bonded to the ends of the model pillars with epoxy provided, during the loading cycle, a lateral end constraint of about 17 to 30 percent of the average axial stress. The effect of this constraint was to increase the breaking strength of the rock as compared to cylindrical pillars without constraint. The percentage increase in breaking strength varied with rock type and increased as the length to diameter ratio decreased. The maximum increase in breaking strength was 35 percent for marble pillars having a length to diameter ratio of 0.5:1. A theory was developed which relates the expected constraint to the physical properties of the ring and rock.

Jan 1, 1968

By W. R. Wrzensinski

This report presents the findings from a l-yr Bureau of Mines program in which sulfur concrete reinforcing materials were tested and evaluated to determine their resistance to corrosion. It also summarizes the permeation characteristics of sulfur concrete and the exemplary performance of precast, reinforced sulfur concrete structures in various industrial environments. The Bureau is furthering the development of sulfur concrete technology as part of a larger effort to find uses for the Nation's plentiful sulfur resources in construction materials. Sulfur concrete is a corrosion-resistant material that can be used in acid and salt environ-ments where conventional materials fail. Penetration of corrosion-inducing agents is minimized because of the low permeation characteristics of sulfur concrete.

Jan 1, 1988

By A. J. Kraemer

"During the past several years a great deal of discussion has centered around the question of the permissible limit of sulphur content in fuels for automotive and aviation motors. Under certain conditions of operation, sulphur in motor fuels causes the formation of corrosive substances which attack bearings, wrist pins, and other parts of engines. On the other hand, in making gasoline from certain stocks, the gasoline fraction normally contains a relatively large proportion of sulphur compounds. By the generally used processes of reducing the sulphur content, a significant part of the gasoline fraction is lost as motor fuel, and added expenses are entailed for chemicals, labor, and other process costs. This condition has been an economic burden to some refiners of high-sulphur crudes. In some instances the treating losses have been rather severe and the treating costs relatively high, but the data presented in this paper indicate that the reduction of sulphur content of motor fuel is a problem to a relatively small number of refiners and of little or no concern to the remainder; in fact, more than 90 per cent of the 153 samples analyzed passed the Federal specification requirement, Which limits the sulphur content to 0.10 per cent. 3This report is based upon the results of an examination for sulphur content, Doctor test, copper strip corrosion, and color of the samples collected during January, 1930, for the twenty-first semiannual gasoline survey of the Bureau of Mines. The results of the gravity ad distillation tests of the survey were published as Report of Investigations 2995. The numbering of the samples given in this report is the same as in Report of Investigations 2995; for example, No. 25 of this report is the same sample as No. 25 of Report of Investigations 2995."

Jun 1, 1930

By C. E. Arthur

The Bureau of Mines has investigated the problem of radioactive contamination using nuclear explosives to fracture petroleum reservoirs in an attempt to stimulate production. It was concluded that some contamination of petroleum products will almost certainly occur. However) the degree of contamination cannot be predicted except by a full-scale experiment) since simulating the problem in the laboratory is economically impossible because of the extremely high temperatures and pressures that must be reached in extremely short time intervals if a reasonable analog is to result.

Jan 1, 1965

By R. V. Ramani, S. Shankar

"The phenomenon of re-entrainment is seen in environments such as sand dune formation, soil erosion, fugitive dust emission and the spread of radionuclides from accidents involving nuclear weapons. A thorough review of existing literature reveals that work on re-entrainment of dust in mine atmospheres is scant. The present study was undertaken as a part of ongoing research at the Generic Mineral Technology Center on Respirable Dust at the Pennsylvania State University on the development of methods to predict ambient dust concentrations in mine atmospheres (Ramani, 1983). The contribution of re-entrainment to the spatial and temporal concentration of dust in mine airways is being studied. The research has included wind tunnel and in-mine studies.A set of seven experiments was performed under controlled conditions in the US Bureau of Mines' Lake Lynn Laboratory mine. Two types of source coal dust, anthracite and bituminous, were subjected to various airflow rates and were subjected to walking by two different individuals. Six sets of instruments were used along the test section for sampling airborne particles. The average air velocity just above the coal dust bed varied between 2.1 to 3.2 m/sec.Due to re-entrainment as a result of the airflow conditions, the average respirable dust concentration in the center of the mine airway increased to 0.09 mg!m3 (standard deviation= 0.03 mg/m3)from an initial value of 0.02 mg/m3. The concentration of all (total) airborne dust increased to 0.17 mg/m3 (standard deviation = 0.10 mg/m3) from an initial value of 0. 02 mg/m3. The action of people walking, however, caused higher amounts of re-entrainment. The average concentration of respirable and total dust at the center of the mine airway increased to values of 0. 28 mg/m3 (standard deviation of 0.12 mg/m3) and 1.53 mg/m3 (standard deviation of 1.0 mg/m3), from initial values of 0.03 and 0.05 mg/m3, respectively. Jr was observed that the dust concentrations were much higher near the floor, immediately at the end of the coal-dust bed.Depending on the level of activity and the amount of dust deposited in the mine airways, re-entrainment may become an important source of airborne dust in areas away from the point of actual mining."

Dec 1, 1996

By Wesley A. Grosh

The Toncrae-Howard copper deposits in Floyd County, Va., were first mined about 1800. The property has been operated or under development at various times since then for iron, copper or sulfur, although the total production has been small. The deposit consists of a vein or zone of sulfide mineralization in schist composed mainly of pyrrhotite with minor copper values in the primary zone and some rich areas of copper mineralization in the altered zone. The Bureau of Mines, in an attempt to develop minable copper ore during the war, opened part of the mine for examination and sampling, deepened the shaft and other underground work, and drilled 29 holes totaling 2,187 feet.

Jan 1, 1948

By H. C. Fuller

Depletion of iron ore in the Nation's large deposits has directed attention to other sources. One of these is the titaniferous iron ore of the Iron Mountain, Wyo., area. Tests were made to determine the feasibility of smelting this ore, which contains about 20 percent titanium dioxide (Ti02), in an electric-arc furnace to produce pig iron. Initial tests, which were made in a 30-pound-capacity induction furnace, demonstrated that the iron could be easily reduced to metal and that limestone was a suitable and effective flux. Larger scale tests then were made in a 50-pound-capacity electric-arc furnace to obtain the more detailed information necessary for the planned continuous operation of a still larger arc furnace. The principal facts determined by preliminary batch-smelting studies were that (1) 9 pounds of limestone flux was required for each 100 pounds of ore smelted, (2) expensive coke was not required because coal proved to be a satisfactory reductant (near stoichiometric carbon was optimum), and (3) overreduction, which produced a viscous slag, must be avoided.

Jan 1, 1961

By Robert H. Peters

How can employees be stopped from engaging in unsafe work practices? It is often easier to prevent employees from performing unsafe acts through manipulations of the work environment than through various training or motivational programs. Therefore, it is important that accident prevention programs seek to identify the reasons for the unsafe behavior and to redesign tasks and the work environment (e.g., tools, equipment, physical surroundings) in order to remove employees from sources of harm and to prevent situations from arising that would prompt them to perform unsafe acts. Unfortunately, in the mining industry the work environment is often innately hazardous, rapidly changing, and difficult to predict, making it very difficult, perhaps impossible, to fully protect the employee by environmental manipulations. Therefore, it is important that effective methods be identified for influencing mine employees to work safely. Various strategies have been used to convince employees to avoid unsafe acts and/or adopt self protective behaviors. The intent of this article is to provide guidance to mine operators concerning the use of four techniques for influencing mine employees to work safely: (1) employee surveys, (2) incentives, (3) fear communications, and (4) disciplinary actions.

By W. G. Pariseau

The U.S. Bureau of Mines has been conducting a series of rock mechanics investigations at the Lucky Friday Mine in the Coeur d'Alene Mining District of northern Idaho. The present study uses rock deformation measurements to validate and calibrate a geomechanical model of the experimental Lucky Friday underhand longwall (LFUL) stope on the 5,100-ft level of the Lucky Friday Mine, Mullan, ID. The calibrated three-dimensional, finite-element model and measurements of rock mass displacement show a correlation of 0.795. The calibration reduces rock mass modulus to 14 to 17 pet of laboratory values and rock mass strength (with an energy rule) to 37 to 41 pet of laboratory values. This model suggested that stress-related ground control problems would be encountered west of the stope where the vein makes a right-angle turn and then splits. Rock burst activity was concentrated in this area during mining of the LFUL stope.

Jan 1, 2010

By Maria I. De Rosa

Table 28 and figure 10 show the number of fires and fire injuries for surface sand and gravel mines by state during 1990-2001. Table 28 also shows the injury risk rates, employees' working hours, and lost workdays. At surface sand and gravel mines, a total of 70 fires with 60 injuries occurred in 29 states during 1990-2001. Fifty-nine of the fires caused 60 injuries (none of the fires involved contractors). The yearly average was 5.8 fires and five injuries. The Ewhr value was 741 x 106 hr (Irr = 0.016), and the LWD value was 6,921. California had the most fires (nine fires and five injuries), followed by Michigan (six fires and six injuries) and Pennsylvania (five fires and five injuries). Of these states, Pennsylvania had the highest injury risk rate value (Irr = 0.052). Table 29, partly illustrated in figure 11, shows the number of fires, fire injuries, risk rates, employees' working hours, and lost workdays by time period. The number of fires and fire injuries show an increase during the second period followed by a decrease during the fourth period followed by a small increase during the fifth period and a sharp decrease during the last period. Employees' working hours increased during most of the periods. The Irr values follow patterns similar to those shown by the injury values.

Jan 1, 2004