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By Maria I. De Rosa

Table 55 and figure 19 show the number of fires and fire injuries for stone mills by state during 1990-2001. Table 55 also shows the injury risk rates, employees' working hours, and lost workdays. In all, 118 fires occurred in 33 states. Seventy-six of the fires caused 82 injuries (including 8 fires and 6 injuries involving contractors). The yearly average was 9.8 fires and 6.8 injuries. The Ewhr value was 873 x 106 hr (In = 0.019), and the LWD value was 1,911. Missouri had the most fires (16 fires and 9 injuries), followed by Pennsylvania (15 fires and 14 injuries), Michigan (9 fires and 5 injuries), and Virginia (7 fires and 5 injuries). Of these states, Virginia had the highest injury risk rate value (In = 0.09 1). Table 56, partly illustrated in figure 20, shows the number of fires, fire injuries, risk rates, employees' working hours, and lost workdays by time period. The number of fires and fire injuries decreased during most of the periods, with a sharp increase during the last period. The number of employees' working hours increased throughout the periods. The In values follow patterns similar to those shown by the injury values. Tables 57-63 show the number of fires by ignition source, method of detection and suppression, equipment involved, location, and burning material by time period. Figure 21 shows the major variables related to fires for 1990-2001. Table 63 shows the fire injuries per number of fires causing injuries and total fires by year, ignition source, equipment involved, and location.

Jan 1, 2004

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 S. H. Katz

Tar and suspended matters are removed from manufactured gas used for domestic and industrial purpose.

Jul 1, 1922

By C. P. Lazzara, R. A. Franks, G. F. Friel, J. C. Edwards, J. J. Opferman

It was determined that a selection of different types of fire sensors could be used to discriminate mine fires from nuisance emissions produced by diesel equipment. A neural network (NN) was developed for application to coal, wood, and conveyor belt fires in the presence of diesel emissions and evaluated with the successful prediction of twenty-two out of twenty-three mine fires based upon a fire probability determination. The optimum sensor selection for the NN was comprised of a carbon monoxide (CO) sensor, two different types of metal oxide semiconductor (MOS) sensors, and an optical path smoke sensor.

By L. C. Headley

Surface areas of two synthetic and three natural consolidated porous samples were obtained by the Orr low-pressure permeametry technique. The results suggest that the Orr technique is a useful substitute for the low-temperature gas adsorption (BET) method for determining the surface area of rock samples. It was more rapid than the BET method, and the surface-area values obtained were larger but agreed better with BET values than values calculated from the Kozeny-Carman equation. Efforts were unsuccessful to demonstrate the influence of channel-size distribution on pressure-flow rate curves by means of experimental data and a parallel channel model.

Jan 1, 1971

By J. C. Edwards

Fire experiments were conducted in the Safety Research Coal Mine (SRCM) at the National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory, with coal, diesel-fuel, electrical-cable, conveyor-belt, and metal-cutting fire sources to determine the response of fire sensors to products-of-combustion (POC). Metal oxide semiconductor (MOS) and smoke fire sensors demonstrated an earlier fire detection capability than a CO sensor. This capability was of particular significance for a conveyor-belt fire in which the optical visibility was reduced to 1.52 m with an increase in CO of less than 2 ppm at a distance of 148 m from the fire. Application of a neural-network program to the sensor responses from each type of fire source resulted in correct classifications of coal, diesel-fuel, cable, belt, and metal-cutting combustion with a mean of 96% of the test data correctly classified.

Jan 1, 2000

By Thomas O. Glover

Cameroon's mineral industry continued to be dominated by crude petroleum, The economic development of the country depended on the production and export of crude on. Output was estimated to be 49 million barrels in 1985 compared with 56 million barrels in 1984 and 47 million barrels in 1988. The country's only refinery consumed approximately 12% of the daily production of crude oil while operating at slightly over 50% capacity. The refinery output, however, supplied the domestic need for motor fuel and heating oils. Cameroon's economic prospects were heavily dependent on the oil sector, which bad been responsible for the recent strong growth in the economy. The country consistently sought to avoid the problems associated with an overdependence on oil and followed a relatively broad-based development strategy, using oil revenues to sustain and encourage growth in other sectors. Approximately 75% of the gross domestic product (GDP) was attributed to the mineral industry in some form. GDP growth was approximately 6.5% during 1985.

Jan 1, 1987

Aid mine operators as well as mine inspectors in making quick but sufficiently accurate measurements of the rock dust content of coal/rock dust mixtures. The Problem Past research has shown that accumulations of volatile coal dust in underground coal mines can be rendered non-explosive by dilution with chemically inert rock dust (usually limestone). Consequently, rock dusting is required by law in U.S. underground coal mines. However, mine officials and inspectors have no quick and reliable means to determine whether enough rock dust has been applied to achieve a mixture that is in compliance with the law. Even the compliance tests used by the Mine Safety and Health Administration (MSHA) are slow and involved. MSHA assures that a mine has been rock dusted adequately by collecting samples from rock dusted areas of the mine and sending the samples to a laboratory for analyses of the inert-dust content. The analyses may not be completed for more than two weeks, during which time the mine in question might be inadequately protected against coal dust explosions. To solve this problem, the Bureau of Mines devised a quick, simple and reliable device that can immediately determine the rock-dust content of a mixture of coal and rock dust.

Jan 1, 1985

By L. D. Tracy

"Introduction In the course of the investigations by the Bureau of Mines into the various causes of coal-mine explosions, the fact that several gas explosions had occurred during or very soon after a mine was being un-watered, attracted the attention of the Bureau's engineers. The apparent coincidence was so marked that there appears to be an extra hazard present, whenever water, which has been standing against the face of the coal for some time, is suddenly removed either by natural drainage or by mechanical means.Actual Occurrences Case 1. - A typical illustration of this hazard is shown in a gas explosion which occurred in a mine in Central Pennsylvania. Four main entries, 50 feet apart with an average grade of 6 per cent, had been driven with the dip of the coal, and from these mains 7 pairs of entries, at intervals of 800 feet, had been turned at such an angle that their grade was slightly rising. Prom these latter pairs of entries, rooms were turned practically at right angles.The main entries had been driven for 4,500 feet and at the face there was 400 feet of cover. As far as could be observed, the roof was of sandstone and the floor of clay.The coal bed being mined was the Lower Kittanning, which has a thickness of about 4 feet. A typical analysis of the coal in that section is as follows:"

Oct 1, 1924

By Earl C. Lane

This is the second of a series of reports on a survey of petroleum products manufactured on the Pacific Coast from California crude oils. California crudes differ in many characteristics from the petroleum produced in other parts of the United States, and the claim has been made that some of the present federal Specifications for petroleum products tend to discriminate against California products. The purposes of the present survey are to determine what particular specification requirements California petroleum products characteristically fail to meet, how widely the products deviate from these requirements, and if possible to show whether the fault lies with the specifications or the products, or along what 'lines investigation to determine the question should proceed. The first report* of the series gave the physical and chemical properties of gasoline and mineral spirits made from California crudes. The present report deals with lubricating oils. Sixty-one samples of lubricating stocks and finished commercial products were generously donated by four of the large refining companies of California. Fifteen samples of automobile lubricating oils, made in California from California crudes, were purchased in the open market. Nine samples of lubricating oils mode from Gulf Coast crude were contributed for comparison by a company in Texas. The refining companies have continued the helpful and cordial cooperation shown by them in connection with the earlier work of the survey.

Jan 1, 1923

By M. L. Fenger, S. F. Mauser

This 1s a report on an Investigation performed during Contract No. H0166069 "High and Medium Voltage Trailing Cable Splices and Connections," which presents a summary of the requirements formulated. The requirements are presented in the form of considerations for medium-voltage splices, and medium- and high-voltage couplers used in underground coal mines.

Jan 1, 1979

By J. C. Franklin

An experiment was conducted by the U.S. Bureau of Mines and the Canada Centre for Mineral and Energy Technology (CANMET) to measure the emanation rate of radon from cemented unclassified mill tailings in two dewatered stopes of a uranium mine at Elliot Lake, Ontario, Canada. The radon was monitored upstream and downstream and in both stopes to determine the concentration in the stopes and the amount exhausted from both stopes. The emanation rate was determined to be 0.55 pCi/cm2 sec-1 from the mill tailings, which is approximately 1,000 times higher than the average flux in the mine before backfilling.

Jan 1, 1982

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

Recently, a collection of programs that will simulate a ventila¬tion system with extensive analyses and report-generating capabilities and error diagnostics has been developed (Didyk, 1974). It has pro¬visions to handle air injections, methane or gas emissions, and leakage. Additionally, it will solve problems where fixed and/or maximum air quantities are specified for some airways. Finally, the simulator has been structured to be extremely modular so that additions and revisions to the model can be easily made. The general aspects of the information flow and logical structure of the mine ventilation simulator are shown in Figure 14. The output from the methane emission model is input into the ventilation simulator for calculation of the concentrations in all branches of the network. The methane model and the ventilation simulator provide powerful tools for the analysis and planning of mine ventilation systems. INPUT DATA REQUIREMENTS In all of the mathematical models, several coefficients that de¬fine the characteristics of the ventilation system are used. For the ventilation simulator, these include the frictional characteristics of the ventilation regulatory devices. Considerable work has been done on the experimental determination of these coefficients for smooth pipes and well-defined mediums, but only limited data are available for actual mining conditions. FRICTION FACTORS: The frictional characteristics of mine airways affect both the dispersion of pollutants and air flow through the roadways,. They

Jan 1, 1975

By Fred Biggs, Walter Utt, Richard Miller

Powered haulage has been, and continues to be, a major source of severe accidents and fatalities at metal/nonmetal surface mines. Between 1986 and 1997, truck drivers accounted for63% of the lost-time injuries in surface haulage. This project was undertaken to reduce the number and severity of lost-time injuries among operators of these trucks. Work involved measuring shock acceleration at a western surface mine during representative work cycles on two types of trucks and collecting data from cab floors using a triaxial accelerometer and from operator seats using a seat pad accelerometer. NIOSH researchers also used the mine’s GPS systems to locate shock events on a mine map in real time. Shock tests were also run at Caterpillar, Inc.’s, proving grounds in Green Valley, AZ, to determine the magnitude of shocks resulting from controlled rock drops onto the bed of a haulage truck.

By R. N. Roby

"INTRODUCTION A preliminary examination of the Green Monster and Benich copper prospects was made by engineers E. W. Newnan and George N. Bennett, of the Bureau of Mines, on December 13, 1943. In an unpublished report, it was stated that certain geologic features appeared to be similar to those associated with the copper deposits of the nearby Butte district. On these premises, a preliminary diamond-drilling program was recommended to explore 300 to 400 feet below the mineralized outcrops for the possible presence of a sulfide enrichment zone. In accordance with that recommendation, three holes were drilled. This report presents the data provided by that preliminary drilling exploration.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell D. Moon, chief, conducts preliminary exminations, perform the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyses samples and performs beneficiation tests.The field work on the Bull Run exploration project was supervised byE. W. Newman engineer in charge of the Helena field office. The chemical analyses and assays included in this report were performed under the direction of A. C. Rice, acting engineer in charge, Bureau of Minos Rare and Precious Metals Experiment Station at Reno, Nev. The diamond-drill cores were logged by geologists of the Federal Geological Survey."

Mar 1, 1947

By Launa Mallett, Charles Vaught, Michael J. Brinich

The lack of good communication is a very real problem in mine emergencies. Sometimes critical information is not communicated to those who need it to make decisions. At other times, those on the receiving end of a warning do not think to ask the right questions. What happens in underground coal mine fires is a case in point. The authors interviewed 48 workers who escaped three serious fires in western Pennsylvania. In each case the location of the fire was known but did not get communicated to many of those who had to evacuate. Sometimes, even the nature of the problem was not clearly communicated. Some workers began their evacuation knowing nothing about what was happening. In an effort to improve emergency communication National Institute for Occupational Safety and Health (NIOSH) researchers worked with safety professionals to determine what sorts of information are critical in a mine emergency. An extensive list was generated, which proved too long to be remembered by individuals. The list was therefore collapsed into six categories. A communication protocol was derived from these categories.

By M. J. Friedel, D. E. Scott, T. J. Williams

Rock masses in deep level mines are subject to high stresses, which can result in unexpected failure of rock into mined-out openings. Historically, various independent methods have been used to discern the causes of rock bursts and to evaluate stress conditions in rock masses susceptible to violent failure. Personnel from two research centers of the former U.S. Bureau of Mines, Spokane and Twin Cities, investigated a rock burst that occurred in May of 1994 in a rock mass between the 4400 and the 4600 levels of the Sunshine Mine, Kellogg, ID. The team evaluated the current state of stress in the pillar and the most likely cause of the rock burst by studying the seismic history of the pillar, examining the geology, analyzing the available in situ stress data, calculating possible fault-plane solutions for the burst, and performing a seismic velocity tomographic survey. The results of the study showed that post-rock-burst seismicity was concentrated about 15 to 30 m west of and about 15 m above the rock-burst location. The pillar is composed of a very hard sericitic-to- vitreous quartzite of a type rarely found in the mine, but that is often found in other district mines having a history of seismic activity. In situ stress analysis of the pillar and the surrounding rock mass showed a probable stress rotation from northwest-southeast to east-west. Of four fault plane solutions, the most probable was either a left-lateral, strike-slip movement with a compressive principal stress oriented nearly north-south, or a right-lateral, strike-slip movement oriented east-west. Finally, tomographic images showed low-velocity areas (interpreted as areas of low stress) associated with the crosscuts and haulageways, and high-velocity areas (interpreted as areas of high stress) associated with the rock-burst location. High velocities were also found in a planar area oriented in an elongate northeast-southwest direction.

By R. D. Leitch

From time to time the Bureau of Mines has received requests from persons who wish to destroy unwanted explosives, and although the information that follows has been accumulated from sources considered reliable,4/ the. Bureau of Mines assumes no responsibility for accidents that may result from following the suggestions offered. Explosives to be destroyed may be fresh material from damaged packages, usable material for which there is no further need, or material that has deteriorated either from natural aging or from improper storage to the point where it is unfit for use.

Jan 1, 1945

By Lauren Roberts, Lewis Martin, John Goris

The Spokane Research Laboratory (SRL) of the National Institute for Occupational Safety and Health (NIOSH) and Thiessen Team USA, Spokane, WA, have developed a pull claw that can be attached to any accessible friction bolt ring to test the performance (i.e., load-carrying capacity) of bolts without the use of a pull collar. This would allow true random testing of friction bolts, which need to be evaluated to determine if they are still providing an adequate level of support months or years after installation. Such support is critical to maintaining safe working conditions for underground miners.

Jan 1, 2004

By Vijia K. Karra

Making sure workers within the aggregates industry go home safely each day is the goal of aggregate companies throughout the United States. At the National Institute for Occupational Safety and Health (NIOSH) researchers are contributing to NIOSH’s vision of safety and health through a fact-finding approach to reducing injuries/illnesses in various mineral sectors. Surveillance data from the Mine Safety and Health Administration (MSHA) has been the primary source for such analyses. It helps to focus research efforts on key machinery, workers, and their tasks. The crushed stone category referred to in this article is represented as crushed and broken stone in the MSHA database.