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By R. S. Conti, C. D. Litton

This U.S. Bureau of Mines (USBM) report discusses the results of research conducted in the USBM experimental mine at its Lake Lynn Laboratory to determine the alarm times of smoke and carbon monoxide(CO) sensors, and a point type heat sensor (PTHS) to slowly developing coal-conveyor belt fires. The tests were conducted at air velocities of 0.44 and 0.97 m/s. The data clearly indicate that smoke sensors provide earlier warning of fire than 10 ppm CO sensors, and that 10 ppm CO sensors provide earlier warning than PTHS. A success rate of 1.0 (indicating detection of every test fire) was obtained for both smoke and CO sensors. For the PTHS, the success rate was 0.57 at the lower air velocity, decreasing to 0 at the higher air velocity. Data are also presented showing the sequence of fire events and detection events at the two air velocities as a function of time. Results show that early detection and warning of underground mine fires will improve the probability of miners’ escape.

Jan 1, 1995

By S. P. Kinney, P. H. Royster, T. L. Joseph

An investigation of the production of iron in the blast furnace is obviously not an easy subject for research . Enough is known of the mechanical , thermal and chemical conditions existing inside the furnace to say certainly that they are complicated. Furnace operators have found that the process is sensitive to a number of known and to many unknown operating conditions . In order to form any conclusions of value , it seems necessary to collect a large amount of data taken with considerable care and accuracy. These facts make a blast furnace research difficult but not impossible . The most serious obstacle in attacking the problem comes from the fact that it is useless in the design and operation of the blast furnace to use the method of " trial and error , which has proved valuable in so many other industrial problems . The variables are so interrelated and are so dependent one on the other that the number of experimental combinations to be tried is enormous . There are certainly not less than twenty factors in furnace operation and design that are known to influence the results . This is apparent if it is remembered that a phrase like " size and shape of the furnace" includes height of the furnace , height , diameter and angle of the bosh , inwall batter , stockline diameter , and furnace volume ; and that a phrase like " chemical and physical properties of the fuels charged " includes size and shape of the lumps , density, porosity and strength of the coke , in addition to its chemical analysis . Let us suppose that we need choose for each of twenty factors one of two values , for example , suppose we must say only that the furnace shall be " tall " or " short , " that the bosh angle shall be " flat " OF "steep , that the ore shall be " coarse " or " fine , " or that the blast has to be "hot" or " cold , " the number of resulting combinations is more than one million . In putting twenty pennies on the table , either heads up or tails up, the number of permutations possible is the twentieth power of two , slightly more than one million. It is obvious , therefore , that some sort of mathematical relationship , a set of rules of thumb , laws , curves or the like , are needed . Whether the relationships , curves or formulas are derived from experiment , from theory, or from mere guess -work, makes no difference provided they agree with the known facts . If they do not agree with known facts , they are worthless no matter what their origin or how weighty the " authority" vouching for them. Few such relationships have appeared in blast- furnace literature , and it may be doubted whether such formulas can be discovered .

Sep 1, 1923

By Henry M. Harris

The Bureau of Mines investigated a glass containing approximately 17 percent lithia and 83 percent silica to establish a method of devitrifying cast and rolled shapes. Glass shapes with high strength were made by melting, forming, and rapid cooling of the composition, and the shapes subsequently were converted to a crystalline condition by heat treatment. The best devitrification schedule included rapid cooling of the glass to below 300° C, followed by reheating at a rate of 50° to 400° C per hour, depending on the size of the shape, followed by a of 60 to 70 hours at 500° C and another period of 15 hours at 800° C. attempts to use faster heating rates or slow cooling to accomplish devitrification in deformation of the shapes. The crystalline shapes had flexural strengths that averaged over 33,000 psi, achieved with an annealing time of 60 to 70 hours at 500° C.

Jan 1, 1965

By Richard L. Rains

The 15,770-acre Worm Creek Roadless Study Area is in southeastern Idaho about 8 miles (mi) west of the northern portion of Bear Lake. U.S. Bureau of Mines personnel examined the roadless, area during the summer of 1984. No mineral resources were identified within the study area. There were no mines or mining claims in the study area in 1984. However, the study area is blanketed with oil and gas leases, but no known productive horizons have been identified within nor nearby. The roadless area is in the Cordilleran fold-thrust belt and is underlain by Paleozoic and Mesozoic marine strata more than 50,000 feet thick. The trace of the Paris thrust fault is 2 to 3 mi east of the study area and has an eastward displacement of about 4 to 7 mi.

Jan 1, 1985

Although early Spanish settlers used coal several centuries ago, significant commercial coal mining in New Mexico began in 1861, when the U.S. Army opened a mine to supply Fort Craig. Since then, coal from the state has been used to fuel railroads, lead and copper smelters, and other local industry. In recent years, lower-cost strip mining methods and an increased demand for coal by electric utilities in the Southwest have caused an increase in New Mexico coal production. The coal-bearing regions of New Mexico underlie about 25,000 square miles or20.6 percent of the total area of the state. However, the majority of coal-bearing regions lie under Indian lands that are regulated by the Office of Surface Mining (see Navajo and Hopi data on pages 72-75). Today, most of the coal produced in New Mexico comes from the San Juan Basin in the northwest part of the state and the Raton Area in the north central part. New Mexico's reserves are estimated to be 4.6 billion tons, about one percent of the national reserve. New Mexico's permanent regulatory program was conditionally approved December 3 1, 1980. Its Abandoned Mine Lands Program was approved July 17,198 1.

Jan 1, 1992

By R. J. Matetic

Researchers associated with the National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Laboratory (PRL), are investigating injuries (fatal and nonfatal) attributed to water well drillers during well drilling activities. Injury data, obtained from various sources, suggest that many water well drillers are experiencing unnecessarily high insurance premiums and very avoidable citations or violations from the direct result of accidents, injuries, and fatalities occurring throughout the water well drilling industry. Expensive insurance premiums and unnecessary citations are the direct result of poor health and safety practices. Visits to numerous water well drilling sites were conducted by NIOSH personnel to characterize and identify the injury data collected and to provide inexpensive strategies to prevent, minimize, and eliminate safety and health issues associated with water well drilling activities.

Jan 1, 2001

By A. F. Jolly

In an effort to better predict the useful service life of friction rock stabilizer mine roof bolts in coal mine environments, the Bureau of Mines has evaluated the corrosion resistance of stabilizer steels in air-saturated and deaerated waters from seven Eastern and Midwestern underground coal mines. Accelerated electrochemical corrosion tests were used to estimate corrosion rates for the two high-strength, low-alloy (HSLA) steels used to fabricate Split Set stabilizers and for galvanized steel. Long-term static-immersion weight-loss tests were also conducted with the HSLA steels. Corrosion rates developed from the weight-loss tests (steady-state air dissolution) were roughly comparable to rates determined from electro-chemical testing in aerated waters. Although the highest rates occurred in waters with the highest chloride contents, rates in the other waters were low (<2.0 mpy) and exhibited little correlation to the widely varied chloride contents of the waters. The generally low corrosion rates are attributed in part to the tendency to deposit a protective CaC03 film, reflecting susceptibility to carbonate precipitation as indicated by positive Langelier (saturation) index values for the waters. With one exception, corrosion rates for the galvanized steel were (2.0 mpy. Rates with aerated waters were higher than those with deaerated waters. Pitting tendencies of the steels were also estimated.

Jan 1, 1987

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 William P. Diamond

Ventilation has long been the primary means of controlling methane emissions in underground coal mines. However, as mining has progressed into gassier areas of U.S. coal basins, supplemental means of methane control have become of interest, if not a necessity, for continued safe and productive mining operations. This paper describes the history and technology of methane drainage in the United States and other countries. The methane drainage technology developed in European countries is a valuable resource since their longer history of mining has already forced mine operators to deal with methane emission problems only now being experienced in the United States. Methods for assessing the need for methane drainage and the data required for planning and implementing an appropriate system are reviewed. The effectiveness of the various technologies for reducing methane emissions underground and/or the in-place gas content of individual coalbeds is illustrated with case studies. In addition to the safety and productivity gains to be realized from methane drainage systems, the potential for commercialization of coalbed methane is discussed.

Jan 1, 1994

By B. R. Mohal, F. F. Aplan, S. Chander

"Dust abatement by water sprays involves the subprocesses of 1) collision between dust particles and water droplets, 2) adhesion of particles to droplets, and 3) engulfment of particles by the droplets. A review of the fundamental aspects of these subprocesses shows that collisions between particles and droplets are determined by aerodynamics and the size and surface charge of the particles and of the droplets. However, the adhesion and engulfment subprocesses depend upon the wetting characteristics of the particles. Although wetting agents (also known as surfactants) have been used as dust suppressants in several investigations, conflicting results are available regarding their effectiveness. In this paper, we show that these results can be explained if the effects of coal rank on surfactant adsorption and wetting characteristics are taken into account.The influence of several nonionic surfactants containing polyethoxy adducts on the wetting behavior of coal is presented. The wetting was determined by a modified Walker Test method, and contact angle measurements. The results show that the wettability of coal depends upon coal rank, structure of the hydrocarbon chain of the surfactant, and the number of ethoxy groups in the molecule.IntroductionDue to the inherent nature of the mining process, a large number of particles are generated, a portion of which becomes airborne to create dust. Dust can be aesthetically and environmentally unacceptable and it can also be explosive. Fine particles in the respirable size range ( < 5 urn) are con-sidered to cause lung diseases, namely, silicosis, pneumoconiosis, etc.(1) Several approaches to reduce dust in mine environments are practiced throughout the mining industry. These include decrease in generation of dust through improvements in mine machinery, ventilation (in which lower dust levels are achieved by dilution of contaminated air with clean air), and dust removal methods. Water sprays are most commonly used to remove dust par-ticles. Recently, scrubbers are reported to have been installed on mining machines to remove dust,(2,3) which also make use of water sprays to reduce dust."

Mar 1, 1989

Vanadium, molybdenum, and a titanium-10 percent vanadium alloy were evaluated for their susceptibility to stress corrosion cracking in a number of corrodents. Tests were conducted utilizing conventional U-bend techniques with subsequent evaluation in a pneumatic constant-load apparatus. Vanadium and molybdenum were generally resistant to stress corrosion cracking in the media studied. U-bend specimens of vanadium showed evidence of stress corrosion cracking in 6 li hydrochloric and 18 li sulfuric acids; however, tensile stress specimens exposed to these solutions did not exhibit stress cracking. Similar results were obtained when U-bend specimens of molybdenum were immersed in 10 percent formic acid. Titanium-10 percent vanadium alloy was susceptible to stress corrosion cracking in 10-percent (2.85 li) hydrochloric acid solution. Heat treating the alloy greatly reduced its corrosion rate and its susceptibility to stress cor-rosion cracking in this medium.

Jan 1, 1965

By Yael Miron

Coal mines that undergo self-heatings, and specifically mines that sustain both floor heave and self-heatings, would benefit from the use of sealants to minimize air ingress to susceptible areas. The U.S. Bureau of Mines(USBM) evaluated three sealant systems for this purpose, bentonite-water mixtures, silicate gel, and guar gum gel. The guar gum-based gel was the only sealant that possessed the desired properties of elasticity, ease of preparation, adaptability to the mine, and a long life. In addition, since the gel consists mostly of water, it could quench or cool nearby heatings. Optimal formulations were determined in laboratory tests, and then tested in the USBM Safety Research Coal Mine. Two formulations resulted in stable gels that lasted for at least 12 months in the mine. Semi continuous preparation of gel using an eductor was evaluated and appears feasible. Although guar gum gel is expensive, selective use to prevent heatings in specific areas would be cost-effective, both interms of productivity and enhanced mine safety.

Jan 1, 1995

By C. R. Stephan, N. B. Greninger, J. R. Lipscomb

The U.S. Bureau of Mines and the U.S. Mine Safety and Health Administration (MSHA) are participating jointly in a research program to evaluate the strength characteristics and air-leakage resistance of various proposed seal designs for use in underground coal mines. The full-scale seals were constructed in the USBM&apos;s experimental mine at the Lake Lynn Laboratory, air-leakage tested, then subjected to pressure pulses of 20 psig or greater. bjected to pressure pulses of 20 psig or greater. In experiments prior to this study, seven seal designs using solid-concrete blocks were tested. Only the standard-type seal passed the explosion and air-leakage criteria. Tests also were performed on four seals constructed with low-density foam blocks. All four of these seal designs withstood the pressure pulse. In more recent studies, nine cementitious foam seal designs of varying thicknesses and densities were investigated. Six of the nine designs successfully survived the explosion overpressures. Six wood- block convergence seals also have been tested. The typical 3-ft-thick, wood-block seal design currently used in many coal mines did not maintain its integrity, in the absence of convergence forces, following the explosion test. Five modified wood-block seals successfully withstood the 20-psig pressure pulse. Based on these tests, three alternative seal construction materials, cementitious foam, low-density foam block, and wood, have been approved by MSHA for use in underground coal mines.

Jan 1, 1993

By R. V. Ramani, C. B. Manula, A. Owili-Eger

• MINE VENTILATION NETWORK PROBLEM (NATURAL SPLITTING; FIXED • QUANTITY BRANCHES; METHANE SIMULATION; NETWORK TOPOLOGY REVISION; • ABSOLUTE PRESSURE) • NFIXB = NO. OF FIXED QUANTITY BRANCHES • DD(I) = AIR QUANTITY ASSIGNED TO FIXED QUANTITY BRANCH I, IN KCFP • NFBPF = NO. OF FIXED QUANTITY BRANCHES PLUS FAN • NFBPFG = NO. OF FIXED QUANTITY BRANCHES PLUS FAN PLUS METHANE • EMISSION BRANCHES • NBWNVP = NO. OF BRANCHES WITH NATURAL.VENTILATION PRESSURE • NVP(I) = NATURAL VENTILATION PRESSURE ASSOCIATED WITH • THE I-TH BRANCH • NF = NUMBER OF FANS • NB = NUMBER OF BRANCHES • MAXIT = MAXIMUM NUMBER OF ITERATIONS • MAXJ = MAXIMUM NUMBER OF JUNCTIONS • NJ = NUMBER OF JUNCTIONS INVOLVED IN THE SOLUTION * NM = NUMBER OF MESHES • NP = NO. OF POINTS TO DESIGNATE FAN CHARACTERISTIC * Q = QUANTITY OF AIR FLOW IN KCFM • R = RESISTANCE OF AN AIRWAY • WIDTH = AIRWAY DIMENSION • LENGTH = AIRWAY DIMENSION • HEIGHT = AIRWAY DIMENSION • SUMNVP = SUMMATION OF NATURAL VENTILATION PRESSURE FOR ANY MESH • X (I) = QUANTITY OF AIR, IN KCFM, ASSOCIATED WITH THE I-TB POINT • ON A FAN CHARACTERISTIC • E = ERROR FOR CONVERGENCE • FF = FRICTION FACTOR • FX(I) = FAN PRESSURE, INS INCHES OF WATER GAGE, CORRESPONDING • • TO A QUANTITY X(I) • H = HEAD LOSS IN INCHES OF WATER GAGE • I = BRANCH NUMBER • J, J1, J2 = JUNCTION, J1 AND J2 ARE TWO NODES WHICH DEFINE A • BRANCH • KEY = NO. WHICH SIGNALS THE TYPE OF FAN CHARACTERISTIC TO BE • EXPECTED

Jan 1, 1975

By Frank G. Schwartz

The Bureau of Mines developed a rapid test method for predicting the stability of motor gasoline during long-term storage. The amounts of gum and inorganic residue formed in 13 gasolines during a l6-hour oven test at 200° F were compared with the amounts formed in the same gasolines stored at 110° F, and analyzed following 8-, 16-, 32-, 44-, and 52-week storage periods. Satisfactory methods were developed for predicting gum and inorganic residue formation during fuel storage periods as long as 32 weeks at 110° F, the approximate equivalent of 5.7 years at 80° F. The only data required to apply the methods are the amount of gum and inorganic residue formed, and the amount of oxygen that reacted, during a l6-hour oven test. A direct relationship existed between inorganic residue formed during the oven test and during 110° F storage. Statistical treatment of the data showed predicted values were as reliable as determined values. By use of a modified Arrhenius equation, the 110° F storage time can be extrapolated to equivalent time at any temperature below 110° F. Thus by combining the stability prediction method with the mathematical extrapolation, the storage performance of motor gasoline for extended periods can be estimated at any temperature up to 110° F.

Jan 1, 1968

By S. A. Matthes

This Bureau of Mines report describes a system for the dissolution of metal and mineral samples using a microwave heat source. Samples and an acid mixture are placed in sealed polycarbonate vessels. The vessel contents are heated using microwaves, digested for 2 min, and quickly cooled. After the solution is brought to a final volume, the vessel contents are heated an additional 2 min in the microwave oven. Using this method, a slag, a feldspar, and a Ni-Cu alloy were dissolved and analyzed by atomic absorption spectroscopy. Values obtained for Na, K, Cu, Ni, Si, Mg, Mn, Ca, Al, and Fe agreed with certified values and had an average relative standard deviation of 1 pct. This system results in a significant savings in time and expense over traditional methods of sample dissolution, and is ideal for preparing solutions for analysis by atomic absorption, plasma optical emission, or X-ray spectroscopy.

Jan 1, 1983

By H. E. Peterson

This report revises an earlier publication by the Bureau of Mines on tungsten analytical procedures and expands the coverage by including appropriate procedures for the critical impurity elements that commonly occur in tungsten ores and concentrates (13).3 The basic methods described are not original, but many of the modifications to improve reliability and sensitivity were developed by the Bureau. Gravimetric and colorimetric methods currently used for the determination of tungsten in ores, mill tailings, and concentrates are described. Colorimetric procedures are preferred for low concentrations of tungsten, whereas either procedure is satisfactory for moderate concentrations. Conversely, a gravimetric method is preferred for the determination of tungsten in concentrates.

Jan 1, 1963

Develop a simple and economical technique for determining the absolute stresses and the change of stress on the surface of roofs, floors, or walls in miners. Approach Use a commercially-available, permissible, Whittemore-type gage to determine the stress at the surface of a mine opening and to monitor any stress changes that might take place. How It Works The following equipment is used: ? One steel templet (for laying out a 60° rosette on the: rock surface). See first photograph. ? One 3/8-inch rock drill bit for drilling holes for the rosette pins. ? Six stainless-steel rosette pins. ? One Whittemore-type mechanical strain gage. ? One drill (not shown). ? Epoxy for cementing the rosette pins. ? Tape to hold the pins while the epoxy sets. The following procedure is used to determine the absolute stress on the rock surface. 1) Spot the location of the rosette pins with the templet. 2) Drill the pin holes and set the pins with epoxy cement. 3) Measure and record the distance between the pins across three diameters of the rosette with a 10-inch Whittemore-type gage. See diagram. 4) Drill a 1 1/2-inch diameter hole in the center of the

Jan 1, 1981

Federal lands often contain extensive mineral resources and decisions affecting access to those lands are made with knowledge of the possible minerals-related consequences. Information is provided to the Bureau of Land Management (BLM) in this report for use in preparing environmental impact statements on the Western Mojave Management Area (WMMA) and the Desert Tortoise Priority Habitat (DTPH). To augment U.S. Bureau of Mines (USBM) efforts such as the Mineral Assessment of the Planned Foil Irwin Expansion, Modified Silurian Valley Alternative, San Bernardino County, California which is in progress, and the Economic Analysis of the Minerals Potential of the East Mojave National Scenic Area; California, the USBM studied mineral deposits and estimated the potential impacts of mining in a segment of the California desert; the 8.7-million-acre WMMA, an area which includes the 1.2-million-acre Desert Tortoise Priority Habitat (DTPH). In addition, this information is intended to assist administrators, legislators, and the concerned public in understanding the economic importance of mineral resources in the California desert, especially that portion designated as the WMMA. See figure 1.

Jan 1, 1993

By J. C. Franklin

The Bureau of Mines substantially reduced shale degradation in a coal mine by two spray coat applications of a water-base epoxy sealant. More than 12,700 square feet of passageways were treated, and in 18 months only one failure occurred. This failure was due to improper spray application, Material costs averaged 13 cents per square foot, and labor costs were 7 cents per square foot. Labor included moving all materials into the mine, the setup time for each of the areas coated, and application of coatings.

Jan 1, 1977