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By Frank J. Susko

The U.S. Bureau of Mines has developed a computer model to describe a flotation process. Coal data from conventional flotation has been converted to a simple, two-parameter kinetic model developed by Reuter and van Deventer (1,2)3. Each set of coal data was represented by two constants, a and ß, and an average flotation rate. The success of the model was demonstrated when the calculated and experimental recoveries showed good correlation. The two-parameter model allows complex data to be defined much more efficiently than traditional knowledge-based models.

Jan 1, 2010

By A. C. Watts, C. A. Allen

In the No. 3 Sunnyside mine of the Utah Fuel Co. a disastrous fire started on the afternoon of August 17 , 1920 , the effects of which are still present in the mine . On account of the extent of the fire , the expense involved in reopening the mine and the opportunities afforded for determining the effects of depleted air , a description of it is worthy of record . This paper is a summary of a more complete report , prepared by the writers , which will be published by the U. S. Bureau of Mines .

Feb 1, 1922

By John R. Benham

The Blue Joint Mtn. RARE II area may contain barite resources. One claim, the Woods Creek Barite No. 1, contains two veins of barite of drilling mud quality. The quantity of barite present could not be determined due to limited surface exposures. Sections 1, 2, 11 and 12 of T. 2 S., R. 23 W. in the study area are classified by the U.S. Geological Survey as prospectively valuable for geothermal energy resources. These sections border Blue Joint Creek Hot Springs, which are outside the study area.

Jan 1, 1981

Develop new technolgies and techniques which enable recovery of strategic and critical minerals such as cobalt from domestic resources, thereby easing the U.S. dependence upon foreign producers for these valuable commodities. Approach The Bureau of Mines, through research, developed a process which uses mineral beneficiation techniques to recover cobalt-rich products from Missouri lead ores. Before development of this process, cobalt was lost as an impurity in the copper, lead, and zinc concentrates and in the mill tailings because the technology to recover it with minimum impact on present production did not exist.

Jan 1, 1989

By Walter W. Fisher

Cement copper was flash roasted in a vertical tube furnace to convert the copper to acid-soluble oxides as part of a postulated process for refining cement copper by oxidation roasting, acid leaching, and electrowinning. The results of the study showed that the oxidation was a linear function of oxygen concentration between 0 and 20 percent, but above 20 percent oxygen there was no further increase in oxidation. Therefore, air was the optimum oxidizing atmosphere in this flash roasting system. The oxidation followed a parabolic rate law as the roasting temperature was increased from 400° to 800° C. Extrapolation of the data, based on the parabolic law, indicated that at 400°, 500°,600°,700°, and 800° C, the roasting times required for complete conversion to soluble oxides were 75, 37, 21, 7.7, and 4.6 seconds, respectively. Cyclic-roasting test results did not substantiate the predictions obtained through data extrapolation.

Jan 1, 1973

By A. W. Hall

Cylindrical plastic scintillators were investigated for efficiency in detecting neutron-induced prompt gamma rays. Scintillator performance was compared on the basis of half-resolution and peak-to-trough ratios for gamma spectra obtained from Co-60 (1.17 and 1.33 MeV), Th-228 (2.62 MeV), and PuBe (4.43 MeV). Various sizes of Pilot Chemical scintillators (types B, F, M, and Y) were tested. The best half-resolution, 7.7 percent for PuBe, was achieved with a 5-by 5-inch Pilot Y?scintillator and dual photomultipliers. Comparison with sodium iodide (NaI) scintillators and the use of plastic scintillators for on-stream analysis of sulfur in coal is discussed. Plastics were found to be unsuitable for on-stream analysis of materials having complex prompt gamma ray spectra; however, they could conceivably be used for those yielding Simpler spectra.

Jan 1, 1974

By Launa Mallett, Charles Vaught, Kathleen M. Kowalski, Michael J. Brnich

This paper reviews research from the U.S. mining community to define issues relevant to an evolving national and international workforce and to relate them to the emergency response population. The authors further explore and relate the key problem of an aging workforce to the resultant changes and emerging physical and psychological needs of emergency workers. Finally, the authors cite examples from the mine emergency response community and mine rescue experiences to suggest practical recommendations that include both organizational and individual formats, with an emphasis on new approaches to training this changing workforce.

By M. J. Beus, M. K. Larson, J. K. Whyatt

U.S. Bureau of Mines researchers reviewed an in situ stress estimate developed from measurements of overcore strain taken at test sites on the 7300 and 7500 levels of the Star Mine near Mullan, ID. Although the field measurements of overcoring strain were found to be useful, significant deficiencies were found in the stress estimation procedure. A new stress estimate was developed incorporating statistical methods and an improved understanding of stress concentration factors for interpreting overcore strains recorded by doorstopper cells. Spatial variability of overcore strains and the implications for stress field variability were explored.

Jan 1, 1995

By Fred N. Kissell

The U.S. Bureau of Mines was established in1910 to reduce .the high accident rate in the nation's coalmines. For 85 years, it conducted a wide variety of tasks related to mining before it was abolished in 1995. The BOM had many technology transfer successes in its lifetime, including more than a dozen "R&D100" awards. This essay identifies and discusses five "transfer factors" that can explain the success (or failure) of many Bureau of Mines projects. These five factors are termed "pressure, pitfalls, path, price, and profit."

By George C. Price

The Bureau of Mines conducted this study in the Roslyn No.5 coalbed in the State of Washington to determine the feasibility of mining hydraulically the portion of the coalbed that was steeply pitching. All of the experimental mining was done while advancing raises and rooms. A Bureau-developed hydraulic mining machine was used successfully in the pitching coalbed. It consisted of a remotely controlled monitor mounted on a self-advancing roof support unit of the type commonly used for roof support in longwall mining systems. The coal cutting rates averaged 0.73 and 0.54 ton per minute in raise and room mining, respectively, while using water volumes up to 230 gpm at a pressure of 4,000 psig. Productivity averaged 4.7 and 5.2 tons per man-shift for raise and room mining, respectively, compared with 7.5 and 8.5 tons per man-shift, respectively, by conventional hand mining methods.

Jan 1, 1965

By K. O. Bennington

[Thermodynamic properties of two amphibole asbestos minerals were determined by the Bureau of Mines. The enthalpies of formation were determined by the hydrofluoric acid solution calorimetry method. Heat capacity measurements were made with an adiabatic calorimeter over the range of 5 to 315 K. High-temperature enthalpies above 298 K were determined with a copper-block drop calorimeter to 852 K for amosite and to 902 K for crocidolite. Thermodynamic data determined for amosite of the composition Fe5+2.2766Mg1.5209 Fe+03.12Mn0.0825) Si7.9163Al0.0837022.0363)(OH)1.9637 are: S°298 = 168.8 ± 5 cal/deg-mole; ?Hf°298-15 (elements) = -2419.24 ± 2.95 kcal/mole; ?Hf298.15 (oxides) = -30.92 ± 2.47 kcal/mole; and ?Gf° -2260.1 kcal. Corresponding data found for s3 ,1s = crocidolite of the composition (Na1.9Ca0.1)(Fe2+.024Fe2.5 01Mg0.475) (Si7.9713024Fe+2 2.501Mg0.475) (Si7.971 Al0.029022.095) (OH)1.905 are: S2.98-15 - 161.1 ± 4 cal/deg-mole; ?Rf° 2 298.15 (elements) = -2433.56 ± 2.99 kcal/mole, 10298.1s (oxides) = -87.69 1.70 kcal/mole, and ?Gf°298.15 = -2269.8 kcal.] Calorimetric values from this investigation were combined with other data from the literature to calculate the Gibbs energies of formation and equilibrium constants of formation over the temperature range of the measurements. Tables of enthalpies of formation and Gibbs energies of formation are given as a function of temperature both from the elements and the constituent oxides.

Jan 1, 1978

By E. K. Kleespies

The Bureau of Mines determined the kinetics of the reaction of titanium-iron alloys with titanium trichloride dissolved in sodium chloride to provide a basis for understanding the reactions occurring in metallurgical processes involving reduction of the metal halides or alloy refining in fused salts. The rate of the heterogeneous reaction was determined between titanium-iron alloys and titanium trichloride to elucidate the effects of alloy composition on the rate. Measurements were made in an inert atmosphere with a high-temperature thermobalance using high-purity reactants. The rates of the reactions were about 1 x 10-5 g Ti/cm2-sec, and the reaction was phase-boundary controlled. Titanium alloys of the body-centered cubic beta structure reacted faster than those with the hexagonal close-packed alpha structure. The inter-metallic compound, TiFe, reacted very slowly, whereas TiFe2 was inert. Alloys containing above 89 atomic percent iron gained weight by reacting with titanium species in the salt solution and depositing titanium in the alloy. The effect of TiCl3 concentration on the reaction rate was determined from 2 to 12 weight-percent TiC13 and at various alloy compositions. At high iron contents, above 50 atomic percent, the TiC13 concentration effect was small. At lower iron contents, the TiC13 concentration effect was greater for beta-crystalline alloys than for alpha-crystalline alloys. The temperature dependence of the reaction between titanium alloy containing 8.7 atomic percent iron and titanium trichloride was measured over the temperature range 1,062° to 1,220° K, and the energy of activation was 7.7 kilocalories for the reaction.

Jan 1, 1967

This chapter presents data on occupational exposures from several sources. Data from compliance samples obtained by MSHA inspectors are presented in table 6-1 for coal mine dust and silica dust, and in tables 6-2 through 6-6 for metal fumes. Since these samples were taken for compliance monitoring rather than as part of a survey of the industry, it is difficult to predict how well they indicate actual exposures for all mining operations. In the coal industry, 7.8% of all respirable dust samples during 1986-1995 were above the permissible exposure limit (PEL). Of silica dust samples obtained during the 10-year period, 23.7% were above the PEL in coal, 16% in metal, 10.8% in nonmetal, 9.1% in stone, and 7.6% in sand and gravel. Of metal fume samples, silver samples showed the largest percentage above the PEL-approximately 48% of samples in both metal and nonmetal. Tables 6-7 and 6-8 present data on noise exposures from the MSHA "dual threshold" survey, which was published in the Federal Register [61 Fed. Reg. 66347 (1996)] as part of a proposed rule change for occupational noise exposure in mining. This study examined a group of samples obtained during 1991-1995 and compared the percent of samples that were above two separate specified limits. The first limit was the current noise standard, a time-weighted average of 90 dBA, calculated to include only exposures at 90 dBA and above. The second limit was a time-weighted average of 85 dBA, calculated to include exposures at 80 dBA and above. Tables 6-8 and 6-9 refer to musculoskeletal overload conditions examined in the National Occupational Health Survey of Mining (NOHSM) [NIOSH 1996]. Table 6-8 shows the operational definitions for each condition; table 6-9 shows the percentage of the workforce potentially exposed, by commodity. Across all commodities, a large proportion of workers were exposed to musculoskeletal overloads due to positioning of the neck and back; positioning and motion of the forearms, arms, and shoulders; heavy lifting; and positioning and movement of the lower limbs. The recorded overloads were defined in the survey and did not exceed any NIOSH, MSHA, or OSHA guidelines for musculoskeletal overloads. Further information on this survey appears in appendix A.

Jan 5, 2000

This pamphlet and the enclosed video describe a safe, effective and economical method for removing dust from work clothes. Background Information Dusty work clothes can increase a worker’s exposure to respirable dust. Respirable dust is usually considered to be particles having an aerodynamic diameter of 10 microns or less and able to enter and deposit in the gas-exchange region of the human lung. A former U.S. Bureau of Mines report documented a 10-fold increase in worker dust exposure on a number of separate occasions from dusty work clothes.* It was found that once clothes become contaminated, they are a continual dust source until cleaned. The only MSHA approved method to clean work clothes requires a HEPA-filter vacuuming system which is very time consuming and difficult to perform effectively. Therefore, most workers use a single air hose (not MSHA approved) which can elevate dust levels for the worker, co-workers, and the work environment. A substantial amount of engineering technology has been developed that, when applied, can significantly lower respirable dust exposures of workers at mineral processing plants. But even with these improvements, some workers continue to exceed their permissible exposure limit. Elevated exposures increase the potential for developing debilitating or fatal lung diseases. ?e clothes cleaning method described within is an example of a continuing effort to reduce the potential for developing these lung diseases. Information about engineering research by the former U.S. Bureau of Mines and NIOSH can be found online at www.cdc.gov/niosh. ?is website can also be used for obtaining NIOSH information about health hazards associated with crystalline silica.

By D. J. Parker

State governments are increasing their efforts each year toward promoting the safety of miners .. Accidents underground are being avoided and mines made safer by means of revising and adding to their mining laws , by enforcing them through mine inspection departments , and by hearty co - operation with other agencies working miners ' safety . The U. S. Bureau of Mines is glad to testify to the co -operation that it receives from State mining departments in its safety work ; reports of the field mining engineers of the Bureau bear witness almost daily to the efforts of the States toward safety in mining . * This Through the courtesy of Mr. William Ogilvie , District State Wine Inspector of District No. 2 , with headquarters at "cAlester , Oklahoma, the Bureau has been furnished with a copy of a letter sent to various mining companies of Mr. Ogilvie's district in Oklahoma, relative to safety in Oklahoma mines . letter shows both the vigorous efforts which the State of Oklahoma is making toward increased safety in mines , and the recognized value of the types of electric cap lamps approved by the U. S. Bureau of Mines as " permissible " for use in gaseous mines ; it is accordingly reproduced in part : "hen during my first inspections of several coal mines in the district I found gas , or fire- darp being given off more or less constantly from the freshly cut coal at numerous points throughout the mines , I became uneasy relative to safety conditions , and am still considering your safety from many angles , but I am more concerned about the gas given off and the coal dust produced daily, than any other factor at the present time .

Jun 1, 1922

By Murali M. Gadde, John A. Rusnak

Rock mass classification systems are extremely useful for site characterization and have been employed by the rock mechanics community for several decades. While empirical in nature, the classification systems provide a viable means to quantify the nature of rock mass, which is necessary for stability analyses. In U.S. coal mines, the Coal Mine Roof Rating (CMRR) is the most widely used classification system for several purposes, including sup-port selection, chain pillar design, assessing the stability of extended face cuts, etc. The Analysis of Roof Bolt Systems (ARBS) is an empirical method developed from the CMRR to guide selection of roof bolts as the primary support system in U.S. coal mines. In this paper, the experience of Peabody Energy in applying ARBS to sup-port design is discussed. In general, data from the Peabody mines show that ARBS predictions match well with field conditions. Peabody, however, does not use ARBS as the stand-alone methodology for support selection. Peabody uses a two-pronged approach in which the support requirement is initially estimated from the classification method, and then numerical modeling is used to select the proper reinforcement system. Such an integrated approach is necessary, as ARBS suggests only the “amount of steel” that may be used to support the roof and does not specify which type of roof bolt to use. A case study is used to demonstrate the usefulness of ARBS and Peabody’s integrated approach to support design. Also, the application of ARBS at several Peabody mines showed a very good correlation with support cost. The correlation indicated a direct relation between bolting cost and the ARBS value.

Jan 5, 2007

By Stephen A. Swan

Bureau of Mines researchers have collected and evaluated rollover protective structures (ROPS) f or more than 10 yr. ROPS and falling object protective structures (FOPS) are required on specified mining machines under regulations of the Mine Health and Safety Administration (MSHA). Both ROPS and FOPS are required on mining machines used in surface coal mines and surface areas of underground coal mines (30 CFR 77.403 and 7 7.4 13a), and ROPS are required on mining machines used in metal and nonmetal mining operations (30 CFR 55, 56, and 57.9-88). This illustrated manual provides mine safety personnel, MSHA inspectors, and original-equipment manufacturers with guidelines and a check- list for inspecting ROPS being used in the field. The manual discusses specific requirements of the MSHA regulations and minimum inspection and maintenance checks for ensuring compliance with those regulations. An easily reproducible checklist is provided as an aid to the inspection of ROPS.

Jan 1, 1985

By E. G. King, W. W. Weller

Low- temperature heat capacity measurements of muscovite were made in the temperature range from 50° to 298 ° K. The entropy at 298.15 ° K was evaluated as S298.15 = 69.0 ± 0.7 cal /deg mole .

Jul 1, 1960

A significant amount of information regarding the crushed stone and sand and gravel industries in each State is available from State agencies and State trade associations. These organizations continuously monitor the State mineral industries and are therefore an important source of detailed information at the local level. This third edition of the directory was prepared to provide a listing of government agencies and trade associations that can assist the users interested in obtaining detailed listings of crushed stone and sand and gravel producers, in addition to the information published by the U.S. Bureau of Mines.

Jan 1, 1994

By A. W. Fahrenwald

Coarse sand flotation, both alone and in conjunction with gravity concentration, is a subject of research at the U. S. Bureau of Mines Field Office, Moscow, Idaho. One of the most important results of this work which is being carried out in cooperation with the University of Idaho, has been the development of a concentration process embodying flotation, classification, and tabling, in the order named. The flow sheet of the process is given in Figure 1. The type of feed desired for this process is coarser than is common in present "all flotation" practice, and is about the size of table feed.

Jan 1, 1929