Search Documents

By K. C. Vincent

In the course of, investigation of domestic manganese-mineral occurrences, examining engineers of the Bureau of Mines collected 2-ton lots of ore from properties in the Cleveland-district, Idaho. As only one of the ores was high enough in grade for direct marketing to-producers of ferromanganese, ore-dressing concentration methods were investigated to determine their amenability to treatment. High-grade ore. (38.7 percent Mn) from the Idaho Manganese Mining Co. was taken from a replacement deposit in limestone consisting of several horizontal beds 1 to 5 feet thick, about 1 mile northeast of Cleveland. The manganese minerals occur as an intimate intergrowth of manganese oxides, containing minor amounts of limonite, ?quartz, and calcite as rather fine inclusions. However, the major contaminants are claylike products of rock decomposition, which can be eliminated by thorough washing of the ore at relatively coarse sizes. The Hot Spot property is 1 mile south of Cleveland. The ore occurs as a replacement deposit of medium-grade- ore in limestone, .The sample taken by the Bureau of Mines assayed 26.0 percent Mn. The manganese minerals consist of nodules, principally pyrolusite with some psilomelane and manganite embedded in wad.' The low-grade wad, containing manganese and siliceous minerals in intimate association, was easily rejected by washing.

Jan 1, 1952

By W. G. Sandell, L. C. Bauerle, K. C. Dean

"INTRODUCTION As a part of the wartime activities of the Bureau of Mines, metallurgical services were extended to other Government agncies engaged in purchasing and stock-piling some of the more critical and strategic materials. At the request of Dr. Alan M. Bateman, special representative of the Metals Reserve Company, metallurgical studies were made on three samples of oxide tin ore from, the States of Zacatecas and Guanajuato, Mexico. The samples were submitted for testing by A. Porraz of the Financiera Miners, S. A., institution Financiera, Edificio Guardiola, Despachos 500-507, Mexico, D. F.The samples as received were marked Nos. 1, 2, and 3 and described as follows:Sample 1. - Origin: Mining camp ""El Naranjo,"" municipality of Sombrerete, State of Zacatecas, Mexico. This sample was partly concentrated by washing and as received was all minus 10-mesh in size.Sample 2. - Origin: Deposits in Sierra. Fria and Juan Cherey, municipality, of Jerez,State of Zacatecas, Mexico. This sample represented run of-mine ore.Sample 3. - Origin: Mine ""La Frontere, "" Ranch of San Pedro del loya, State of Guanajuato, Mexico. This run-of-mine sample was low in tin content but came from a highly mineralized tin field."

Jun 1, 1947

By T. H. Jeffers

Significant amounts of cobalt are present in readily accessible spent copper leach solutions. The Bureau of Mines investigated the feasibility of extracting cobalt from these solutions in a multiple-compartment ion-exchange (MCIX) column. The effects of aqueous flow rate, resin flow rate, column height, and compartment height on cobalt extraction were determined. Cobalt extractions of 92 pct or higher were achieved at solution flow rates of up to 5.5 gpm/ft of column cross-sectional area and an aqueous-to-resin flow ratio of 40:1. Overall cobalt extraction increased as the column height increased, but cobalt extraction per unit of length was more efficient in 8-and 12-ftco1umns than in an 18-ft column. Solvent extraction procedures were utilized to purify and concentrate the MCIX column eluates and produce a cobalt sulfate solution containing 70 to 80 giL Co. Metallic cathodes containing over 99 pct Co were e1ectrowon from this solution. Zinc, nickel, and copper byproducts were also recovered during processing of the ion-exchange eluates. Estimated total capital cost for a commercial-scale 10,000 gpm of a spent leach solution containing 26 million. With credits for zinc, nickel, and copper estimated net operating cost was $9.36/lb Co.

Jan 1, 1987

By Alexander E. Morrow

Oxygen breathing apparatus for use in mines was introduced to the United States in 1907. Despite their intended purpose of safeguarding lives, the apparatus led to the deaths of many men because of inherent or developed defects in the equipment, lack of training,, physical shortcomings of wearers, and improper procedures. The Bureau of Mines pioneered in research and training to curb logs of life among users of such apparatus and promoted development of safer equipment and procedures. As a consequence, deaths have been far less frequent. In 1944 the Bureau issued Information Circular 7279, Loss of Life Among Wearers of Oxygen Breathing Apparatus. That publication listed the case histories of 26 deaths that had occurred since the introduction of such equipment to American mining. The author, the late G. W. Grove,3/ asserted that further loss of life could be avoided if good equipment were used, teams were properly trained, and the basic principles of safe procedure were followed. This publication is a sequel to I.C. 7279 and contains information on eight deaths among wearers of oxygen breathing apparatus that were overlooked in the original compilation. It also describes the single death that occurred since I.C. 7279 was published.

Jan 1, 1959

By M. A. Trevits, J. E. Urosek, A. C. Smith, M. P. Valoski

The National Institute for Occupational Safety and Health (NIOSH), in partnership with the Mine Safety and Health Administration (MSHA), is conducting research to test, evaluate, improve or modify coal mine fire-fighting strategies and methodologies through large-scale tests. Since wood is the second most abundant fuel available during a coal mine fire, it was decided that series of large-scale wood crib fire tests were needed to measure the products of combustion and to observe the capability of commonly available direct application fire suppression equipment, namely, fire extinguishers, water and gas-enhanced foam. This paper discusses the wood crib fire tests, provides insight into the products of combustion and describes observations made during the application of the fire suppression agents.

By W. W. Adams

Lower accident rates were the outstanding feature. of the second annual sand and gravel safety competition conducted in 1930 by the United States Bureau of Mines in cooperation with the National Sand and Gravel Association. Both the frequency and, severity rates for accidents were greatly reduced as compared with those shown by the first year's contest, that for 1929. Three times as many plants were enrolled, and the number of man-hours of work represented wad more than doubled. Seventy-six sand-and-gravel plants, situated in 20 States, participated in the competition, as compared with 26 plants, located in 13 States, in the year before. The number of man-hours of employment, which indicated the amount of exposure to occupational hazards, was 4,915,592 an increase of more than 100 per cent over, the previous year's total of 2.259,572 hours. The frequents of accidents declined from 74.4 per million hours for all plants enrolled in the first year's contest to 42.7 per million man-hours for all plants enrolled in 1930. The accident-severity rate was reduced from 9.7 days of disability per thousand man-hours of exposure in 1929 to 5.9 days of disability per thousand man-hours of exposure in 1930.

Jan 1, 1931

By William W. Adams

The quarrying and related industries of the United States improved their safety record in 1938 by reducing their accident-frequency rate to a lower acid more favorable position than it has occupied at any time except 1935 since comparable accident statistics became available in 1916. The rates for 1935 and 1938 were identical. The number of men employed in 1938, although smaller than in 1936 and 1937, was larger than in any other year since 1930. Volume of employment, as measured by the number of man-hours worked in the industry as a; whole, likewise was larger than in any year since 1930 except 1936 and 1937. Reports from operating companies to the Bureau of Mines, United States Department of the Interior, showed that 77,497 men were employed in 1938, a decrease of 6,597 compared with 1937. This figure represents the average number of employees for the period during which the quarries and plants were active during the year, which in 1938 averaged 223 workdays per employee compared with 241 in 1937. A total of 17.3 million man-days or 133.8 million man-hours of work was shown for the industry as a whole, which indicated a weighted average of 7.75 hours per man-shift. Reports for 1937 showed a total of 158.3 million man-hours for the entire industry and an average workday of 7.81 hours. Accidents resulted in the death of 82 employees, 5 more than in 1937, and in 5,027 nonfatal injuries involving disability for more than the remainder of the day on which the injuries were received. The number of nonfatal injuries was 1,321 less than in 1937. As the number of deaths and injuries was reduced more, proportionately, than man-hours of employment, the accident-frequency rate per million man-hours of work declined, the rate for 1938 being 38.19 compared with 40.59 for 1937. In other words, accident occurrence to the average employee was 6 percent more favorable in 1938 than in 1937 on the basis of actual number of accidents and actual number of man-hours worked during the 2 years.

Jan 1, 1940

By K. L. Williams

The Bureau of Mines tested a prototype tapered-element oscillating microbalance (TEOM) dust monitor for measuring respirable coal mine dust. The monitor uses the inertial behavior of a vibrating element to measure the mass of sampled dust. Tests were performed to determine variability, drift, the effect of humidity, placement of collection filter, and element orientation during analysis, and comparability with gravimetric measurements of respirable coal dust. Variability was about 1.6 µg. Over about 26 h at 46 pct relative humidity, drift was very slightly negative. When the relative humidity was increased to 78 pct, all units showed a total positive change less then 40 µg over about 70h. Filter placement variation on the tapered element resulting from in- consistent sizing of the filter mounting bases caused significant error (up to 0.2 mg). In practice, calibration of the system for each new filter will eliminate that error. Orientation of the element during analysis did not introduce significant error, but care is necessary when mounting the canister that houses the element to avoid damping oscillation of the element. Dust tests were performed in an aerosol chamber using coal dust. Measurements made by the TEOM dust monitor agreed to within 10 pct of simultaneous measurements by gravimetric personal samplers.

Jan 1, 1986

By Lawrence H. Roth

Past failures of coal refuse embankments have resulted in more intensified efforts in inspections of coal refuse sites. Inspections, however, are mainly qualitative and time consuming. In August 1975 CH2M HILL was awarded a contract to identify, develop, and test a rapid system for monitoring coal refuse embankments to aid in inspections. The rapid monitoring system developed uses convergent and vertical photography from conventional fixed-wing aircraft. The system was tested on an active landslide and on two coal refuse facilities using both black and white and color infrared film. Field tests showed the system was capable of accurate measurement while providing qualitative data through photointerpretation. The accuracy of the system allows it to be used to monitor coal refuse embankments, tailings dams, major earth dams, and natural slopes. Bibliographies of literature reviews in the area of past coal refuse embankment failures, monitoring instruments and methods, and photogrammetry are included.

Jan 1, 1977

By James A. Wasson

This report summarizes the results and conclusions reached by various investigators who have attempted to determine the extent to which hydraulic fracturing will affect the secondary recovery of crude oil by waterflooding. It also discusses the most advantageous use of this well-stimulation method in waterflood projects. A thorough search of the literature was made, and pertinent information was abstracted from appropriate reports. A carefully designed and controlled program of formation fracturing is an effective aid in waterflooding because it increases water-injection and oil-production rates. Generally, fracturing has resulted in little or no reduction in ultimate oil recovery, but under certain circumstances recovery has been substantially increased.

Jan 1, 1963

By E. R. Spencer, E. R. Bauer

Previous studies and research efforts have shown that noise-induced hearing loss (NIHL) is a problem in the U.S. mining industry. In response, researchers at the National Institute for Occupational Safety and Health (NIOSH) have been conducting a cross-sectional survey of equip­ment noise and worker noise exposures in the mining industry to estimate the potential for NIHL within the mining community. One commodity recently surveyed was the extraction of sand and gravel from surface pits and by dredging. To address the potential for NIHL in the sand and gravel industry, sound levels on and around the dredges and processing equipment were recorded to iden­tify areas of high noise levels. Full-shift worker dosimetry, in conjunction with task observations, was documented to determine the relationship between exposure and source. This paper presents research examining noise on dredges used in several surface mine sand and gravel operations and in the processing facilities. Results indicate that there are areas on the dredges (crane, suction pumps and diesel engines) where sound levels greater than 90 dB(A) are pres­ent. In addition, crushers and screens used in the processing of the sand and gravel also generate sound levels greater than 90 dB(A). Although no surveyed worker exceeded the Mine Safety and Health Administration’s (MSHA’s) permissible exposure level (PEL) of 90 dB(A) eight-hour time-weighted average (TWA8), laborers, mechanics, oilers, helpers, pickers and greasers are the workers most likely to be exposed to hazardous sound levels and to thus develop NIHL over time

By D. K. Deardorff

The hafnium-vanadium phase diagram was constructed within an estimated accuracy of ± 10° C and ± 2 wt pct composition. Alloys for investigation were melted under an atmosphere of purified helium by nonconsumable tungsten-electrode arc melting on a water-cooled copper hearth. Melting points were determined by optical pyrometer, and the remaining phase relationships were investigated by metallography, thermal analysis, and X-ray diffraction. The existence of a face-centered cubic intermetallic compound HfV2 (a = 7.38 A) was confirmed. A eutectic reaction occurred at 20 wt pct vanadium and 1,395° C to yield HfV2 and 8 solid solution. HfV2 melted incongruently by a peritectic reaction at 1,480° C, and the 3 solid solution decomposed eutectoidally at 1,165° C and 6 wt pct vanadium to yield HfV2 and a solid solution. The eutectoid, the eutectic, and the peritectic isotherms extended from 1 to 36.3 wt pct vanadium, from 8 to 36.3 wt pct vanadium, and from 26 to 89.5 wt pct vanadium, respectively. Terminal solid solubilities of hafnium in vanadium at 1,300° C and of vanadium in hafnium at 1,100° C determined to be about 3 and 1 wt pct, respectively.

Jan 1, 1965

By G. M. Kintz

From 1895 to 1932, inclusive, 1,0163/ men were killed in and about New Mexico coal mines. Of these, 473 (approximately 47 percent) were killed in the 17 explosions listed in this paper. The second largest explosion of record in the United States, in so far as fatalities are concerned, occurred in New Mexico. The data in this circular were taken from publications of the United States Bureau of Mines and published annual reports of the State inspector of coal mines of New Mexico. The tables included are complete only with regard to major disasters. The Bureau of Mines considers as a major disaster one in which 5 or more men are killed. A few minor disasters are included, however.

Jan 1, 1934

By W. R. Hardwick

Nuclear explosive fracturing has been suggested as a method to make hard rock amenable to extraction by a modified block-caving method. To evaluate this possibility, conventional and nuclear blasting practices are discussed, underground mining methods for large deposits and their costs are described, and the cost of fracturing ore with a nuclear explosive and subsequent mining by a modified caving system is estimated and compared with both open-stope and block-caving mining costs. While the direct cost of fracturing the ore in hard rock with a nuclear explosive is less than with conventional explosives, additional costs imposed by the use of nuclear explosives may make their use unattractive for deep mining.

Jan 1, 1970

By W. P. Yana, J. B. Littlefield

"INTRODUCTION AND OBJECT OF EXPERIMENTAn explosion in and rupture of a gas-tight switch box on an electric loader in a mine located near Pittsburgh indicated that the cause was an internally generated inflammable gas-air mixture. This led to the suspicion that moisture condensation or ""other unusual conditions might have caused a spark or are across the surface of the material and that the heat may have created a carbonized path across the synthetic plastic base which would then conduct a large current with the generation of considerable heat and thermal decomposition of the base materials base in the box which exploded gave every indication that this series of events had taken place, and accordingly it was desired to determine what explosive gases such a decomposition of these insulating materials would produce.ACKNOWNLEDGMENTSThe desirability of making this investigation was suggested to the authors by L. O. Ilsley, supervising engineer, electrical section, Bureau of Mines, to whom the occurrence of an explosion in a switch box had been reported. The writers also acknowledge with thanks the assistance of L. B. Berger, chief scientific aide, health laboratory section, Bureau of Mines, in checking the calculations in the tables. DESCRIPTION OF MATERIAL INVESTIGATEDThe ten materials used in the tests, identified by letters A to J inclusive, are described in a succeeding list of materials. All the materials except I had a phenolic odor, especially when freshly cut."

Dec 1, 1932

By Lucia Kuizon

The Cactus Springs Roadless Area Review and Evaluation (RARE II) study area (No. A5188) comprises 12,800 net acres (5,180 ha) in San Bernardino National Forest in west central Riverside County, California, about 20 air miles (32 km) southeast of Palm Springs. Mineral investigations are made by the U.S. Bureau of Mines on National Forest lands identified as Further Planning Areas in the RARE II program. The Bureau of Mines reviewed literature, mining claim records, and production files; examined the study area; and mapped and sampled mineral properties where appropriate.

Jan 1, 1983

By Thomas W. Camm

This study was done to evaluate the costs of various dumping operations at waste and spoil piles. It has been theorized that accidents associated with dumping operations might be reduced by short-dumping rather than edge-dumping, but many operators have been reluctant to use short-dumping because they believe it is not as cost effective as edge-dumping. To evaluate this perception, researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health reviewed the costs of various dumping methods at waste and spoil piles. The study found that overall cost differences between the two methods were not significant in most cases. However, while overall cost differences between the two methods appear small, capital costs could be more significant when short-dumping if numerous dump sites are used concurrently. The choice of which method to use should be based on considerations of the safety of dozer and truck operators.

Jan 1, 2000

By B. K. Shibler, A. O. Ipsen, W. W. Agey

"INTRODUCTION As a part of the program of investigation of domestic sources of manganese ore, mining engineers of the Bureau of Mines obtained and examined samples of ore from six properties in the vicinity of Pioche, Lincoln County, Nev., and from one property near Caliente, Lincoln County, Nev. As the ores were too low-grade to be acceptable for the direct production of ferromanganese, their amenability to concentration by ore-dressing methods was investigated.In general, the Pioche ores had a low manganese content and, owing to extremely intimate association of manganese minerals with iron oxide and nonmetallic gangue, were refractory to concentration by ore-dressing methods. Only two samples (Zero Gap and Wheeler ores) were amenable to the production of concentrates that would sinter to a marketable plus 35-percent manganese grade. The Prince Consolidated and Ely Valley No. 1.ores were roasted and sintered to produce lead-silver-zinc fumes. The residues were of possible value as manganiferous iron ore. No marketable manganese products were made from Calton semi-oxidized ore, but over 80 percent recoveries of lead, silver, and zinc were made by bulk sulfide flotation followed by Diming of the sulfide concentrate. No satisfactory results were obtained by treatment of Golden Eagle and Ely Valley No. 2 ores.The Cudverwell ore was amenable to the production of high-grade manganese concentrates by ore-drssing methods. However, fine grinding was required to effect mineral liberation, and loss of manganese as slime limited the mangenese recoveries obtainable.In the coarse of the investigations, many data were obtained and compiled, but for the sake of brevity, several data, of secondary importance have been omitted or condensed, and only the tests giving the more promising results are discussed in detail. For convenience, the report has been divided into two parts, one opertaining to the Pioche ores and the other summarzing results obtained by testing Culverwell ore."

Aug 1, 1947

By Robert M. Cox

The U. S. Bureau of Mines (USBM) MULSIM/NL modeling technique has been used to analyze anticipated stress distributions for a proposed alternative longwall gate road design for a western Colorado coal mine. The model analyses indicated that the alternative gate road design would reduce stresses in the tailgate entry without increasing stresses in the headgate entry. To test the validity of the alternative gate road design under actual mining conditions, a test section of the alternative system was incorporated into a subsequent set of gate roads developed at the mine. The alternative gate road test section was instrumented with borehole pressure cells, as part of an ongoing USBM research project, to monitor ground pressure changes as longwall mining progressed. During the excavation of the adjacent longwall panels, the behavior of the alternative gate road system was monitored continuously using the USBM computer-assisted Ground Control Management System. During these field tests, the alternative gate road system was first monitored and evaluated as a headgate, and later monitored and evaluated as a tailgate. The results of the field tests confirmed the validity of using the MULSIM/NL modeling technique to evaluate mine designs.

Jan 1, 2010

By D. Harrington

Fine ventilation was discussed. much more 15 to 20 years ago than it is now, yet today there are tendencies in connection with ,-line ventilation (in fact, numerous ventilation systems have been installed in recent years) indicating that the lessons learned by bitter experience in the past either have been forgotten or lave not been brought to the attention of the present generation. Possibly, the mining min of today considers that conditions have changed so much that experiences of the past cannot be repeated today. At any rate, it seems desirable to restate some of the principles of mine ventilation that were understood more or less in the past and to call attention to some danger in connection with present-day trends or practices.

Jan 1, 1939