Search Documents

By D. Harrington

Most of those in the Health and Safety Branch, Bureau of Mines, necessarily participate in activities associated with essentially all phases of the mineral industries, including coal and noncoal mines, quarries, smelters, metallurgical plants, and various petroleum operations. One of the strictly war activities of the branch - the Explosives Control Division, which administers the Federal Explosives Act of December 26, 1941 - has functions that require contacts not only with nearly all phases of the mining and allied industries but also with those engaged in scores of other occupations that manufacture, store, use, or possess explosives, or many of the ingredients of explosives. The field men of the Health and Safety Branch (approximately 300 in number) Are occupied full time in health and safety activities and annually make thousands of contacts with people in the mineral industries as well as the plants in which they work. From these they formulate several thousand written reports containing sources of thousands of conclusions and recommendations aimed at reduction of health end safety hazards in these industries. Although such activities have been greatly increased during the war and immediate pro-war periods, they have been in effect to a considerable extent since the Bureau of Mines was created in 1910.

Jan 1, 1944

By G. H. Wigton

This paper, describing the concentrator practice of the Chief Consolidated Co., is one of a series being prepared by the United States Bureau of Mines. The concentrator adjoins the town of Eureka, Utah, in the Tintic mining district. The Chief Consolidated, Eureka Lilly, Plutus, and Grand Central mines, all of which are owned or controlled by the Chief Consolidated Mining Co., are the principal sources of milling ore. The ore is transported from mines to mill by railroad. Although all the mines are within 3 miles of the mill, the railroad distance varies from 1 mile to 12 miles.

Jan 1, 1930

By Gene Asai

The Bureau of Mines investigated the caustic extraction of alumina and soda from retorted dawsonite-bearing oil shale, as part of a program to devise technology for treating alternative domestic sources of alumina for the production of aluminum metal. Colorado oil shale yielding 13 pct oil (35 gal/ton) and containing 12 wt-pct dawsonite (representing about 4 pct extractable alumina) was retorted to obtain oil-free (spent) shale Spent shale was leached with dilute NaOH to determine the effect of particle size, retorting temperature, leaching variables, and storage conditions on extraction of alumina and soda and dissolution of impurities. Maximum alumina and soda extractions were obtained by promptly leaching minus 28-mesh spent shale, obtained by retorting raw shale at about 5000 C, with 0.5N NaOH. Under these conditions, dissolution of impurities such as Ca, Fe, Ti, and P was low. Leaching tests were made on spent shale stored for periods of up to 30 days at 0° to 42° C and at 0 to 100 pct relative humidity (RH). These tests indicated that significant reductions in alumina extraction would occur if spent shale were stored in ambient Colorado air under naturally fluctuating temperature and humidity.

Jan 1, 1983

By D. J. Parker

Before the various States began to enact workman's compensation laws accidents were considered inherent in many industries, and little or no effort was made to prevent or reduce them. The hazard was accepted by the employee with the job, and the avoidance of accidents by mental alertness or physical agility was largely his responsibility. After the employee had given evidence of enough skill inn performing his allotted task efficiently the responsibility of the employer apparently ceased with respect to the personal safety of the employee. However, following the enactment of workmen's compensation laws, at least two facts that had not before been fully appreciated soon became apparent: (1) The majority of accidents can be prevented if the management firmly determines to prevent them; (2) frog a monetary point of view alone accidents are decidedly expensive, both to employer and to employee. It is now evident that savings effected by conscientious safety effort add substantially to net profits of operation.

Jan 1, 1934

By J. Sammarco

Proper illumination is critical to a miner?s ability to detect hazards in underground mines. Moving hazards are often located in the miner?s peripheral field-of-view, while slip/trip/ fall hazards are often located in the forward field-of-view. The objective of the research described in this paper was to determine if light-emitting diodes (LEDs) improve visual performance as compared to traditional incandescent (INC) cap lamps. The research presented focuses on comparative studies of a National Institute for Occupational Safety and Health (NIOSH) prototype LED, a commercial LED and an INC camp lamp. Thirty subjects participated in these studies, with ten subjects in each of the following age groups: 18 to 25 years, 40 to 50 years and 51+ years old. Visual per­formance was quantified by the subjects? speed and accuracy in detecting hazards, while visual performance for disability glare was quantified by the use of contrast sensitivity tests. Results suggest that LEDs with a visible spectrum containing a higher concentration of the shorter wavelengths can enable visual performance improvements with respect to disability glare, the detection of moving hazards in the peripheral field-of-view and the detection of floor hazards in the forward field-of-view. The NIOSH prototype LED cap lamp provided the best visual performance improvements for the older age groups in every test.

Jan 1, 2009

By Arthur Matzick

The oil shale from the Mahogany zone of the Green River formation in northwestern Colorado has the greatest potential in the United States for early utilization. A large reserve of adequately rich shale is available to support a sizable industry, and crushing of tremendous tonnages will be required if conventional processing methods are used. This report presents Bureau of Mines data on crushing experiments, physical properties, and related information for Colorado oil shale. Among the properties important to crushing are slab-forming tendency, resilience, slippery character of the richer grades, and heterogeneous nature of an average charge of Colorado oil shale.

Jan 1, 1960

By D. A. Buckingham

The Bureau of Mines evaluated potential availability of domestic nickel from 23 deposits, Evaluations included an estimation of in situ and recoverable resources, applicable mining and processing technologies, and capital and operating costs. Discounted cash flow analysis with a 15-pct rate of return was used to determine the average total cost of production of each operation, Identified in situ resources contain 9.0 million metric tons (t) of nickel; 5.5 million t is recoverable as nickel metal or ferronickel. Demonstrated in situ resources contain 8.2 million t of nickel; 4.8 million t is recoverable as nickel metal or ferronickel. No nickel is available at a total cost of production equal to the January 1983 market price of $3.24 per pound. Analyses indicate that potential annual production can only meet current consumption levels at a total cost of production of $7.60 per pound of nickel, Nickel's availability is contingent on (1) successful adaptability of nickel processing methods to domestic resources, (2) location of a smelting facility, and (3) marketability of byproducts and coproducts. Analyses were performed on the effects of byproduct and coproduct revenues, energy, labor, and transportation costs, and metallurgical recoveries on nickel's availability.

Jan 1, 1984

In 2005, a total of 263 metal mining operations reported employment to the Mine Safety and Health Administration (MSHA). Metal mines were the smallest mining commodity sector, comprising 1.8% of all mining operations. ? Gold mines comprised 46.0% (n=121) of all metal mining operations. Other common types of metal mines were iron ore (n=32; 12.2%), copper ore (n=31; 11.8%), and lead and/or zinc ore (n=16; 6.1%). ? Nevada had the largest number of metal mines (n=52; 19.8%), followed by Alaska (n=27; 10.3%).

Jan 1, 2008

By D. J. Donaven, Manuel Gomez, W. S. Landers

Bulk density tests were made on a Western U.S. coke oven plant blend to obtain bulk density control data that would be directly transferable to plant practice . Maximum bulk density values were obtained at zero surface moisture . Increase in surface moisture to about 6 percent decreased the bulk density to a minimum value . Increase in the fine grinding of the blend , at constant surface moisture , decreased the bulk density . The effect of oil on bulk density was observed with five oils at concentrations ranging from 1/8 to 1-1 / 2 gallons per ton . Maximum bulk densities were obtained within the 1 / 2- to 1 - gallon - per - ton range . Essentially the same bulk densities were obtained with petrolatum- and nonpetrolatum- containing oils . Storage effects were observed on samples tested at selected intervals from 0 to 56 days . No significant change in bulk density took place if no surface moisture was lost during storage .

Jan 1, 1964

By V. F. Parry

[Approximatel~r 7-1/2 illion tOlls of subb1tnminous coals are mined an-nuall in Colorado, Wyo~ing, and Montana, of which 50 percent probably reaches dome ,-tic conswno:os. r:L'he moi s t'_re of the se subbi t1.Uninous coal sis high, averae;:t.:ug about 25 :!,)ercent \-Then they are :nined. T'ne coals are non-caking d ~~ack to a vari ble degree when exposed to nornal atmospheric conditions. ~hey a~e gpod domestic fuels, are considered to be smokeless in most furn~ces, and have been used. f, r f!1an: y ars in hand-fired domestic furnaces in hich tnc practice i~ to e~ploy large lureps for efficient com-]

Jan 1, 1941

By Richard L. Sanford

This report summarizes the results of the development of a Directory of Computer Programs Applicable to U.S. Mining Practices and Problems. The Directory includes a sampling of computer usage in operating and manufacturing companies, consulting firms, computer companies, research organizations, universities, and various U.S. government agencies. References to computer applications throughout the mining industry are presented as well as comments on the availability of programs to interested organizations or individuals.

Jan 1, 1977

By Henry E. Perlee

Air compressor explosions that are caused by the ignition of combustible vapor mixtures cannot be explained by a single reaction mechanism or sequence of events. Explosions have been caused by the sudden release of large quantities of lubricating oil, by the rapid vaporization of oil that had accumulated slowly in high-pressure piping, and by the production of decomposition products from carbonaceous deposits. Ignitions can be caused by the heat produced in a catalytic reaction, in a compression process, or when a shock wave is propagated through a combustible vapor-air mixture. The frequency of these ignitions can be minimized by establishing proper maintenance and cleaning schedules. Further study is needed to satisfactorily correlate the various factors involved in compressor explosions.

Jan 1, 1963

By P. M. Sullivan

A physical beneficiation flowsheet was designed by the Bureau of Mines for reclaiming and recycling metal and mineral values contained in municipal incinerator residues, and a continuous processing plant was installed. Residue samples collected from incinerators located in various parts of the country were processed at a rate of 1/2 ton per hour. Continuous screening, shredding, grinding, magnetic separation, and gravity concentration techniques were applied to produce metallic iron concentrates, clean nonferrous metal composites, clean fine glass fractions, and tine carbonaceous ash tailings. Research to develop systems for refining and upgrading the reclaimed metals and glass into marketable products is also underway. From the engineering data developed in the continuous processing plant, evaluations of the capital and operating costs for plants with capacities of 250, 400, 670, and 1,000 tons of dry incinerator residues per day were made. Research on a parallel system to separate and recover the metals, minerals, glass, paper, and plastics from raw, unburned refuse it currently underway, as are studies on the use of air classification to separate the refuse into organic and inorganic fractions.

Jan 1, 1971

By R. A. Bloomfield

This report summarizes Bureau of Mines contract research on the disposal of retorted oil shale. A data base has been developed describing the physical-chemical properties, geotechnical engineering properties, and natural cementation characteristics of spent shale. Results of field compaction tests and seepage pond tests are presented, along with results of a partially saturated finite element seepage model used to predict infiltration and seepage rates. Preliminary engineering analyses are presented for underground disposal systems, which include material transport methods, and for a surface disposal system, which includes stability analyses.

Jan 1, 1981

By John Owens, Hamid Maleki

Efficient and safe use of mobile roof supports (MRS) depends on the interaction between the MRS and coal strata. Of particular interest to this study are the mechanics of strata deformation as influenced by geologic conditions, pillar extraction methods, and MRS load-bearing capabilities. To provide a better understanding of the mechanics of strata deformation, the authors have collected and reviewed measurements of convergence and stress in one western U.S. mine and have completed pseudo-three-dimensional, boundary-element modeling for two typical pillar-pulling plans. Stress distribution in the mine roof above pairs of MRS’s was calculated to demonstrate how MRS’s contributed to the control of roof block movements. It was shown that overall stress and roof-floor convergence patterns were most influenced by the stiffness of coal-measure rocks and by pillar-pulling sequences and layouts. MRS’s and other support systems play a critical role in controlling the stability of both the immediate roof and the middle roof for a distance of up to 18 m (60ft) above the seam. MRS’s provide unique ground control advantages over other types of secondary support by significantly reducing the time between mining and installation of secondary support. Although MRS’s are similar to posts in stiffness and capacity, they are more effective than posts under static loads because they can yield and still maintain loads at near-peak capacity, whereas posts fail and loose their ability to limit mine roof deformation.

By Mark Flower

A 20L ignition test chamber has been used to test suspensions of 7 UK and world traded coals in air and O2/CO2 mixtures typical of oxy-combustion conditions. The coals varied in rank from sub-bituminous to bituminous and were tested in varying concentrations from the ignition limit to 400g/m3. Following each successful test the combustion residue was collected, weighed and analysed within a thermogravimetric analyser, allowing Q factors to be estimated. The ignition limit varied slightly in air, but was mostly around the 200g/m3 level. With the exception of Coal C, which was much harder to ignite, it correlated roughly with coal rank. The ignition limit changed significantly with O2 concentration when in mixed O2/CO2 gases. Only a few high volatile coals ignited in 21% O2/CO2 v/v, and then only with a 2500 J, rather than a 1000J, igniter. An increase in O2/CO2 levels to 30 or 35% gave ignition patterns similar to those carried out in air with a further increase to 40% having little additional effect. In addition the minimum ignition concentration decreased with increase in O2. Heterogeneous combustion or gasification of the coal by CO2 appears to be confirmed by comparing weight loss results for air and O2/CO2 mixtures respectively for an equivalent peak pressure rise.

Jan 1, 2009

By Frank J. Wiebelt

Under a general program to extend the resources of mineral deposits, the Bureau of Mines examined the Quien Sabe antimony mine in October 1948. The preliminary evaluation demonstrated that a diamond-drill program was warranted co establish the tenor and persistence of the veins and permit an estimation of antimony reserves. The Bureau of Mines conducted a diamond-drilling program on the property from December 1949 to May 1950. Ten holes aggregating 2,483 feet were drilled. Nine of the holes encountered antimony-bearing vein material.

Jan 1, 1956

By C. M. McKinney

This report contains Bureau of Mines analyses of 291 samples of crude petroleum from the Gulf Coast Area of Louisiana and Texas. Included are 65 analyses from 51 Louisiana fields and 226 analyses from 216 Texas fields. Analyses from the Texas fields include 90 from 58 Upper Gulf Coast fields, 47 from 28 Middle Gulf Coast fields, and 89 from 40 Lower Gulf Coast fields. The analyses represent fields that produced 1,000 barrels or more per day during at least one of the years 19.57 through 1961, with the exception of 23 analyses from the Texas fields. The fields considered are listed by state and geographical groupings, with field names arranged alphabetically within each grouping. The tabulation also includes information concerning the geological sources of the samples. General characteristics of the crude oils and analytical and computed data determined from the analyses are summarized. Crude oil production data are given for the fields for 1960 and 1961 and are cumulative through 1961.

Jan 1, 1963

By R. F. Zaffarano

Reservoir oil in the Greater Aneth area, Utah, part of the Paradox basin, was studied to detect variation in oil characteristics within the reservoir and to determine its relation to age of accumulation and fluid equilibrium. At least three subsurface oil samples were obtained from each of the four largest of five field divisions comprising a producing area of 45,000 acres. Height of the oil column in the Pennsylvanian Desert Creek zone is about 230 ft. In general, the oil characteristics were found to be uniform across the area, and averages were developed for use in engineering applications. Average saturation pressure was 1,780 psia; the oil was undersaturated at the initial reservoir pressure, 2,200 psia. Variation in saturation pressure shows a lack of complete fluid equilibrium and continuing diffusion of solution gas from the main body of the reservoir to two extensions linked by narrow arms. By assuming early accumulation, the time involved in this diffusion process was calculated to be about the same as the age of the reservoir formation. Cause of the concentration of gas in the main body is attributed to differential entrapment during accumulation of oil and gas from an exterior source.

Jan 1, 1963

By Henry E. Perlee

Air compressor explosions that are caused by the ignition of combustible vapor mixtures cannot be explained by a single reaction mechanism or sequence of events. Explosions have been caused by the sudden release of large quantities of lubricating oil, by the rapid vaporization of oil that had accumulated slowly in high-pressure piping, and by the production of decomposition products from carbonaceous deposits. Ignitions can be caused by the heat produced in a catalytic reaction, in a compression process, or when a shock wave is propagated through a combustible vapor-air mixture. The frequency of these ignitions can be minimized by establishing proper maintenance and cleaning schedules. Further study is needed to satisfactorily correlate the various factors involved in compressor explosions.

Jan 1, 1963