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By M. R. Yenchek

The Bureau of Mines conducted research to determine the relationship between cur-rent load and temperature rises in coal mine trailing cables. Six low-voltage, unshielded, portable power cables were continuously and intermittently loaded with direct current of various magnitudes. Temperature rises within and on the cables were measured with thermocouples, and the data were recorded with a computer. Thermal time constants were calculated, which fixed the periods of the duty-cycle tests. Relationships between average temperature at the conductor-insulation interface and current load were established. The steady-state and intermittent currents that produce a 90° C average conductor-insulation temperature were then determined. Comparisons with Insulated Cable Engineers Association (ICE A) steady-state ratings revealed that 10 to 25 pct more current than recommended ICEA ampacities is required to reach rated insulation temperature. Examination of the maximum intermittent temperatures attained showed that autoignition of coal dust and burn injuries to personnel handling the cable would not be concerns if the temperature at the conductor-insulation interface averaged 90° C.

Jan 1, 1988

By Ernest V. Deshayes

The Colorado Minerals Co. calcite properties in Archuleta and Hinsdale Counties, Colo., (fig. 1) were examined by Bureau of Mines engineers in 1943. The demand for optical calcite during the war prompted the examinations and resulting development programs on the Meadows and Seavy ranch properties near Pagosa Springs, Archuleta County. Development was begun on the Meadows property in November 1943 and continued to the Seavy ranch property. The work consisted of stripping the overburden from the calcite areas and excavating pits and trenches with a bulldozer. The pits and trenches exposing the most promising calcite veins were then deepened by hand, and one shaft was sunk to a depth of 30 feet. A total of 36 trenches and 9 pits were excavated by bulldozer and. hand methods (figs. 2, 3, and 4). The calcite deposits occur as veins and irregular bodies filling fractures in the Mancos shale of Cretaceous age. The fractures persist for considerable distances along the strike, although the calcite filling may not be continuous for more than a few feet. The widths of individual veins range from a few inches to several feet. The calcite crystals uncovered at the surface and in pits, trenches, and shafts were found to be unsuitable for optical purposes because of fracturing and color in the crystals.

Jan 1, 1949

By Thomas J. Peters

In 1978, the U.S. Bureau of Mines and the U.S. Geological Survey completed a joint mineral survey of the Chemise Mountain and King Range study areas as mandated by the Federal Land Policy and Management Act of 1916, Public Law 94-579. The U.S. Bureau of Mines examined all identified mineral prospects and deposits; the results of these examinations are included in this report. The U.S. Geological Survey studied the regional geology, geochemistry, and geophysics; the results of these studies are available in USGS Map MF-1196. No mineral resources were identified in either the Chemise Mountain or King Range study areas; however, a high-grade silver and base-metal occurrence, and minor manganese resources were identified in between the two study areas, within the King Range Conservation Area. The only mining activity in either area was a placer gold prospect on Honeydew creek in the northeastern part of the King Range study area. Three samples from this prospect contained no gold. The Chemise Mountain and King Range study areas are in a mountainous region along the coast of northern California, 230 road miles north of San Francisco, and 70 miles south of Eureka by way of U.S. Highway 101, through Garberville and Redway. The Chemise Mountain study area consists of 3,941 acres; it includes the 2,598-ft Chemise Mountain, and the cliff-lined seacoast southeast of Shelter Cove. a resort and fishing village. The King Range study area consists of 39.764 acres northwest of Shelter Cove, and includes the northwest-trending King Range with elevations above 4,000 ft. The Chemise and King Range study areas are underlain by deep-water marine sandstones, shales, and minor pillow basalts of the Late Cretaceous and early Tertiary Franciscan Subduction Complex. Mineral production was 1,650 tons of manganese ore within a manganiferous bed overlying pillow basalt at the Queen Peak mine southeast of the King Range study area. However, no significant manganese resources were found in the Queen Peak area. The Point Delgada area, directly south of the King Range study area, has prospects with high grade copper, lead. silver, and zinc. Exposures are inadequate to estimate resources; however, the metals may be associated with Franciscan volcanism (volcanogenic). The Chemise and King Range study areas may contain similar economic silver-rich, base-metal deposits.

Jan 1, 1992

By Spangler Ricker, F. T. Johnson

"SUMMARYThe Ione-Carbondale clays area is 2 miles northwesterly of Ione, Amador County, Calif. It was explored during the war by the Bureau of Mines to obtain data on the alumina content and to recover representative samples for beneficiation tests for alumina recovery.Seventy holes, aggregating 8,837 feet, were drilled, and about 10.3 acres of land was cleared of underbrush. Maps and cross sections were compiled showing location of holes, analyses, and other pertinent data.The clay beds vary in thickness from 13 to 196 feet, and are covered by a loose overburden, averaging about 11.9 feet in thickness. The ratio of overburden to clay is 1 : 8.2. Analysis of a composite sample showed the recoverable alumina (A12O3) and Fe2O3 content to be in the order of 23.6 percent and 2.8 percent, respectively.Topography of the clay area is ideal for open-pit mining methods and plant site.INTRODUCTIONInvestigation of alumina-rich clays for the possible production of aluminum was made during the recent war period, when the shortage of bauxite was becoming critical.Results of field examinations by the Bureau of Mines and the Federal Geological Survey indicated that one of the most promising areas for the development of alumina-rich clays is in the Ione-Carbondale district."

Mar 1, 1948

This Bureau of Mines report summarizes the research, development, and evaluation demonstrations conducted by the Bureau of Mines under the Health and Safety Act of 1969 to improve the means of notifying miners underground, who are away from their own phone, that they are being called.

Jan 1, 1977

By Andrew Allan

[Research conducted by the Bureau of Mines hrinq the last 5 years on the uce of machines for 7!naer:rolmrl ?.eve loym~nt in pi.t,c hlng anthracite beds l~a~ provide? data ?howin? that ?:;panrt of thc roof an9 str?eg of thes? oTen - jnqs requires almst half of' the PRS? workin? time. The possibilitie~ of i!rinz a mvable,. te1.ee*co@. c tpr? 3f ?tee1 ~h-!.oltl at the face in~tetcrl of conventional wood a*ti~yorts w?r? si:~q~eteil by engineers engaqad on the~ work If ~uch a shi~l8 COLI.~,~. be ~sve~.~yad, it tnillil man that face workera w~uld be provi8ed with mulrnu.m prot?ct+on from falls of' roof and ribs mi! the en- tire ehift could he I~W? Lo ~lro,J.~:ce cocl. Fermanent tim3er coald be p'l.acnA behind the shielR independently of the 'face work as the face advanced.]

Jan 1, 1953

By W. D. Mcmillan

Although the Shafter district of Presidio County, Tex., is principally renowned for silver production from the Presidio mine, the occurrence of lead-zinc ores in the western part of the district has been known for at least 50 years, and there has been some production. An area of about 3 square miles in the vicinity of an extending westward from the Presidio mine was investigated in detail by C. P. Ross of the Federal Geological Survey in 1934. In the fall of 1943, A. B. Needham, an engineer of the Bureau of Mines, called the attention of the Geological Survey to the area west of that included in Ross's map, and requested a detailed investigation of that area by the Survey in advance of development by the Bureau of Mines. After a brief reconnaissance by the Survey in the spring of 1944, detailed studies were made by Federal geologists in the summer of 1944, during which about 450 acres were surveyed, on a scale of 1 inch to 100 feet. Recommendations for the exploration of certain parts of the area were made in the accompanying report.

Jan 1, 1949

By Patrick D. Plumb

The Bureau of Mines (BOM) has begun a project to increase the understanding of the relationships between ecosystem health and its functions, and minerals development. The BOM, Juneau Branch, Alaska Field Operations Center, is providing support for ecosystem based land-management decision-making and the development of ecosystem based regulations by documenting the effects of mining on ecosystems and demonstrating the tools used to assess and analyze those effects. This is done by reviewing the data available on ecosystems and the environment at a mining site, the Greens Creek Mine near Juneau, Alaska, and applying available Geographic Information System modeling tools to assess the impacts of the mine on components of the pristine ecosystem. Habitat Capability Models for wildlife indicator species are used in this examination. Wildlife indicator species are used as indicators of ecosystem health by the U.S. Forest Service and the Alaska Department of Fish and Game, who developed these models for southeast Alaska. Analysis techniques from the U.S. Fish and Wildlife Service's Habitat Evaluation Procedures (HEP) are also used in this report. By applying available models and analytical techniques to the Greens Creek area, the benefits gained through mitigation of potential impacts become apparent. These or similar techniques are useful for cost/benefit analysis of mitigation alternatives. Also apparent from this analysis is that the degree to which potential impacts are observable will depend upon the ecosystem scale considered. This demonstrates the importance of defining the ecosystem and scale before performing impact and cost/benefit analysis. The watershed scale is found to be useful for assessing impacts to ecosystem components at the Greens Creek Mine. Much progress remains to be made in the modeling and prediction of impacts to ecosystems from mining activity.

Jan 1, 1994

By David Garry, Michael J. Brnich, Lynn L. Rethi, Henry P. Cole, William J. Wiehagen, Roberta A. Calhoun

This document contains most of the materials needed to use the exercise. The main part of the document is the instructor's copy. It tells how to use the exercise, presents the objectives, the master answer sheet, the scoring key, and discussion notes to be used following the exercise. The next section summarizes results from field tests of the exercise, and reports the miners' evaluation of the activity. The last part of this document is three appendices. Appendix A is the exercise problem booklet. This booklet can be duplicated locally. The booklets are reusable. One is needed for every person in the classroom. Appendix B is the answer sheet and the trainee's questionnaire. Copies of this answer sheet must have the latent image (invisible) ink answers that appear in Appendix C printed on them.1 Answer sheets are consumable. One is needed for each person or each small group of persons who work the exercise. Exercise Summary Read this section first. It determines if the exercise is appropriate for your classes. If you choose to use the exercise, examine the table of contents and review the remainder of this document. Type: Latent image Audience: Supervisors, Safety Personnel and Accident Investigators Length: Eight questions (30 minutes for administration plus 30 for discussion) Skills: Developing a strategy or plan to prevent slips and falls Following correct procedures in conducting an accident investigation Preventing unsafe work practices Recognizing and instituting hazard controls in the section Identifying and implementing safe work procedures Location: Underground coal mine section Problem: You have been the general mine foreman at White Rock Mine for 4 years and have worked at this mine for 12 years. The mine superintendent calls you into his office. He gives you an accident report of an employee in 4-G section who was injured while carrying rock dust bags from the rock dust car to a battery powered scoop. It is several days after the accident and the mine superintendent assigns you and the safety supervisor to thoroughly investigate the accident to determine all the contributing factors. Your job is to make specific recommendations to prevent future slipping/tripping accidents.

Jan 10, 1999

By Jr. Watts, B. K. Cantrell, D. H. Carlson, K. L. Rubow

"The use of diesel equipment in underground coal mines is controversial because ""whole diesel exhaust"" is regarded as ""a potential occupational carcinogen"" by the National Institute for Occupational Safety and Health (NIOSH). Threshold limit values (TLVs) are recommended for the gaseous pollutants; CO, CO2, NO, NO2, SO2, and some hydrocarbons emitted in diesel exhaust. There is, however, no TLV recommended for diesel exhaust aerosols (DEA) nor is there a standard method for sampling these aerosols.The University of Minnesota and the Bureau of Mines have collaborated to develop a personal diesel exhaust aerosol sampler (PDEAS) which utilizes size selective, inertial impaction and gravimetric analysis. During the field tests of this sampler, numerous air quality measurements were conducted in underground coal mines using diesel equipment. The objective of this report is to present these data and to assess the impact of diesel face haulage equipment on mine air quality.Air quality data were collected in four underground coal mines using continuous mining methods with diesel haulage equipment. Daily samples were collected at the section intake, haulageway, and on haulage vehicles. Both full-and partial-shift samples were collected using a variety of aerosol instruments, including the PDEAS and the micro-orifice, uniform deposit impactor (MOUDI) which sample the mine aerosol diesel exhaust fraction. Two of the mines were also monitored for the major gaseous constituents found in diesel exhaust CO, CO2, NO, NO2, and SO2. These measurements were made by either collecting bag samples for subsequent gas analysis or by Palmes dosimeters.The concentrations of CO, CO2, NO, NO2, and SO2, were well below regulated levels. The mine average DEA concentration determined by the PDEAS in the haulageway for the three mines surveyed using this instrument was 0.79 mg/m3, with a standard deviation of 0.19 mg/m3. DEA contributed 65% of the respirable aerosol, at this location. These results were the same as the mean DEA concentrations calculated from size distribution measurements obtained using the MOUDI. This was 0.78 mg/m3, with a standard deviation of 0.22 mg/m3."

Mar 1, 1992

By T. M. Romslo

The Lake Shore property, located in the early 1880's, contains copper-bearing deposits that have been developed by surface excavations, underground workings, and churn-drill holes. Operation of the property ended in 1929 with a total recorded production of 280,000 pounds of copper. The property is near the foot of the Slate Mountains, which are made up mainly of probably the Pinal formation of pre-Cambrian age. In the mine area there are a few outcrops of granite, which is exposed over a large area east of the property. Other outcropping rocks on the property are limestone, quartzite, and diabase. The limestone and quartzite probably are the Mescal and Troy formations of pre-Cambrian and Cambrian age, respectively. The predominant copper mineral is chrysocolla, a hydrous silicate that occurs mainly as fracture filling in bedded schist. It is also, the principal copper mineral in the shear zone at the schist-granite contact and in limestone southeast of the main workings. Investigation of the Lake Shore property by the Bureau of Mines included both topographic and geologic mapping, exploratory drilling, and metallurgical test work. One diamond-drill, hole and five churn-drill holes were completed for a total of 2,872.5 feet. Drilling started January 19 and was completed May 13, 1949.

Jan 1, 1950

By Michael L. Clar

This volume is an annotated bibliography of published literature pertaining to the occurrence and control of surface and groundwater in underground coal mines. This literature was used to develop Volume 1 of this report, which assesses the feasibility of water diversion and overburden dewatering for underground coal mines in the Appalachian Region. Each abstract is followed by subject descriptors. the abstracts are listed alphabetically by title and are numbered consecutively. These numbers are used in the subject index to help the reader locate the appropriate articles.

Jan 1, 1981

By W. W. Adams

"Accidents at coal mines in the United States in September 1926 resulted in the loss of 170 lives, according to information furnished to the Bureau of Mines, Department of Commerce, by State mine inspectors. Of this number 125 occurred at bituminous mines and 45 in the anthracite field. As the bituminous output of coal for September was 48,976,000 tons, and the production of anthracite was 8,444,000 tons, the fatalities reported represented a death rate of 2.55 per million tons for bituminous mines and 5.33 for anthracite mines. The industry as a whole showed a fatality rate of 2.6 per million tons of coal produced in September 1925 the rate for bituminous coal mines was 3.29; the anthracite mines were idle in September last year due to a strike.During the first nine months of the present year 1,759 men have been killed by accidents at the coal mines throughout the United States, resulting in a death rate, per million tons of coal produced, of 3.76 as compared with 3.95 for the same period in 1925. Reports for bituminous mines alone showed a nine-month fatality rate of 3.53 which was about the same as the corresponding rate from January to September in 1925. The anthracite rate for the present year, however, shows a decrease of about 17 per cent; that is, the rate has declined from 6.36 to 5.28.Records covering the first nine months of 1926 show that 12 ""major"" disasters, that is, disasters in which five or more men were killed at one time, have resulted in the loss of 271 lives as against 10 disasters and 199 deaths in the corresponding months in 1925. The fatality rates for these disaster: alone were 0.579 and 0.465, respectively. One major explosion occurred at Tahona, Oklahoma, on September 3, 1926, in which 16 men lost their lives.An analysis of the principal causes of the 1,759 fatalities for the first nine months of the present year shows a reduction in the death rate as a whole and for falls of roof and coal and for explosives, but an increase in haulage, gas and dust explosions, and electricity. The comparative rates for these accidents were:"

Oct 1, 1926

In spite of advances in measurement techniques and an explosive increase in the volume of research, our understanding of human strength remains in its introductory stages. It is clear that muscle strength is a highly complex and variable function that depends on a large number of factors. It is not surprising, therefore, that large differences in strength exist not only between individuals, but even within the same individual tested repeatedly on a given piece of equipment. The issue is compounded by the fact that correlations of strength among different muscle groups in the same individual are generally low, and tests of isometric strength do not necessarily reflect the strength an individual might exhibit in a dynamic test. As a result of these and other influences, great care needs to be exercised in designing, evaluating, reporting, and interpreting muscular strength assessments. Traditionally, tests of muscular strength were in the domain of the orthopaedist, physical therapist, and exercise physiologist. Such tests are also an important tool for the ergonomist, however, because of the high strength demands on workers in manual materials-handling tasks. In some cases, task demands may approach or even exceed the strength that an individual is voluntarily willing to exert in a test of strength. In such cases, evidence suggests that the likelihood of injury is significantly greater than when the task demands lie well within an individual's strength capacity. Because the relationship among strength capabilities, job demands, and musculoskeletal injury has been established, it is apparent that tests of muscular strength may benefit the ergonomist both in designing jobs and in ensuring that individuals have sufficient strength to safely perform physically demanding jobs. Several strength assessment techniques have been employed for these purposes, each possessing unique characteristics and applicability to job design and worker selection procedures. Our main purpose has been to elucidate these strengths and weaknesses, so that tests of strength may be properly applied in designing jobs and selecting workers. One of the crucial points we have emphasized is that any test of strength used in job design or worker selection must be directly related to the demands of the job.(1) For example, if an occupational lifting task has a high dynamic component, a test of isometric strength is not likely to provide the data necessary for proper design of the job. Of course, dynamic strength tests would also be misapplied in assessing a job requiring isometric exertions. Another potential pitfall is using tests of strength on isolated muscle groups and assuming that they are indicative of whole-body strength. For example, one might mistakenly assume that dynamic trunk extension strength represents a person's capability to perform a lifting task. However, an individual's lifting capacity may be entirely unrelated to trunk extension strength. It may, instead, be limited by an individual's arm or leg strength, depending on the task being performed. A final point on strength assessment should be made. An individual's strength capability cannot be considered a fixed human attribute. Strength training regimens can increase an individual's strength capability by 30%-40%. Whether

Jan 1, 1998

By J. Bootle

Marrow vein deposits will continue to be an important source of valuable minerals. Productivity per manshift is not keeping pace with operating costs. Increased mechanization of stoping operations must be obtained to create greater productivity at a reduced cost per ton. This application of mechanization may be to either present methods or to newly developed concepts. The total mine unit operations will be effected by increased productivity. Two approaches to increasing the mechanization of narrow vein stoping were studied with the intention of increasing stope productivity and decreasing stoping costs. A method of bringing efficient rubber-tired equipment into narrow cut and fill stopes was designed. It proposes to provide stope access by way of a ramp constructed on the stope fill. Impact breaking equipment was studied and specific applications proposed.

Jan 1, 1977

By J. B. Janus

This report, the 22d in a series, gives analytical data showing composition and quality of tipple and delivered samples of coal collected during fiscal year 1972. This coverage lists mines located in 20 States. Ultimate analyses are given for most of the coalbeds listed. Tipple samples were collected by Bureau of Mines engineers at tipples as coal was being loaded into railroad cars or trucks. The deliveries were sampled in accordance with instructions issued by the Bureau of Mines, and the samples were analyzed in the Bureau laboratory at Pittsburgh.

Jan 1, 1973

By G. E. Rennick

An oil well penetrating the Pittsburgh bituminous coalbed in northern West Virginia was plugged and safely mined through 3 months later. A sensitive chemical tracer, introduced into the oil reservoir before the test, was not detected in the mine air following the plugging and during mining of the pillar and penetration of the well. Effectiveness of the plugging in preventing reservoir gas from entering the mine through the well hole was verified by continuous monitoring of the mine air for indications of sulfur hexafluoride, an inert gas detectable in amounts as minute as 1/2 part per billion. Expandable cement and fly ash-gel-water slurry were utilized to seal the well above and below the coal seam. Three other wells were also plugged using various techniques.

Jan 1, 1972

By Michael D. Balen

This Bureau of Mines open file report is one in a series of reports written about the Valdez Creek Mining District (VCM D) as a result of the continuing Bureau of Mines mining district evaluation program. This report presents the results of order-of-magnitude mining feasibility studies. The mining feasibility studies were conducted for mineral deposit models that were based on real and hypothetical deposits that occur in the VCMD. A total of 6b mine models were developed for application to the mineral deposit models. The goal of the feasibility study was to determine the monetary value per unit of minable ore that would cause the simulated cash flow for each of 66 mine models to achieve certain pre-defined rates of return for the invested capital.

Jan 1, 2011

By Robert G. Lundquist

This report summarizes all relevant findings and conclusions regarding capabillty of high-energy projectile impact to operate effectively in an open pit mining environment and to successfully handle secondary breakage and bench scaling problems. A silenced, aimable, mobile projectile launcher was designed and fabricated, utilizing a Government-furnished smooth-bore, 90 mm cannon. The silenced launcher was tested at the contractor's test site prior to shipment to ANAMAX Mining Company's Twin Buttes Mine near Tucson, Arizona. Demonstration tests were conducted at an inactive waste dump in the mine on 39 oversize boulders to determine the relationship between boulder size and projectile energy required for secondary breakage. The high energy projectile impact method (known by the acronym REAM -Rapid Excavation and Mining) was tested on an additional 23 boulders in the working mine and on 31 areas of potentially loose rock high on the pit walls. Most of the secondary breakage tests were successful and acceptable for open-pit mining purposes without producing large amounts of fly rock. Five of the 31 scaling tests were successful with one shot, but most of the remainder required two or more shots, and a few could not be dislodged because they were not as loose as they appeared to be, based on visual examination from a distance. Cost comparisons between the REAM method and conventional methods of secondary breakage and bench scaling are discussed. A film documentary, REAM--Mining Applications of High Energy Projectile Impact, has been produced by the contractor depicting the applications of the silenced cannon.

Jan 1, 1976

By Frank C. Andreuzzi

The Division of Environmental Activities, U.S. Bureau of Mines, conducted a solid waste demonstration project on a burning coal refuse bank. The primary objective of this project was to develop and evaluate an efficient method of extinguishing burning coal refuse and moving it. A series of tests were performed using water monitors and related apparatus to quench the burning material and, at the same time, using earth-moving equipment to transport, spread, and compact the extinguished material. The method found to be most effective consisted of water-quenching the surface material to a workable depth, ripping, and removing the quenched material with a bulldozer and tractor-scraper. The total cost was estimated to be $0.44 per cubic yard.

Jan 1, 1970