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By W. H. Ode, W. A. Selvig

In 1938 , the Bureau of Mines cooperated with Subcommittee XV on Plasticity and Swelling of Coal ( C. C. Russell , chairman ) , of Committee D-5 on Coal and Coke , A.S.T.M. , by testing various methods for determining expansion and plastic properties of a series of coals of widely different coking properties . One of the tests made by the Bureau was the British Standard Method for the Crucible Swelling Test for Coal.5/ Briefly , this swelling test consists in heating 1 gram of pulverized coal in a silica crucible over a gas flame under prescribed conditions to form a coke button which is compared in size and shape with a series of standard profiles numbered 1 to 9. These profiles are intended to cover the size and shape of buttons obtained from coals covering a wide range in plastic properties .. The number of the standard profile with which the maximum cross -sectional area of the button most nearly corresponds is recorded as the swelling index . Although the swelling test showed poor relationships with the various tests that were used for measuring expansion or contraction of coal during carbonization , it gave indications of having value in measuring free - swelling and caking properties of coals when burned on fuel beds . An opportunity to investigate this occurred when an engineer of an eastern public utility 'company reported pronounced differences in burning characteristics on grates of various shipments of Pocahontas coal . Some of these coals gave trouble by swelling 'excessively and clogging the grates . Samples were ob- · tained , and it was found that the troublesome coals gave decidedly higher free -swelling numbers than did the coals that performed satisfactorily . Also , it was found that the free - swelling index test gave better differentiation between coals than could be obtained from the coke buttons from the · ´`standard volatile -matter test or from agglutinating - value results . The results of the free - swelling tests were considered by the Subcommittee on Plasticity and Swelling , and a special group of the subcommittee , under the chairmanship of R. A. Sherman , was delegated to study the test method . Ostborg , Limbacher , and Sherman , ofthe Battelle Memorial Institute , ' investigated the various factors affecting the test and found that the swelling index was a good indication of the suitability of coal for performance on residential -type stokers from the standpoint of the coking characteristics of the coal . Data were presented also showing that the indexes wer helpful in the selection of coal for industrial underfeed stokers .

Oct 1, 1946

By A. R. Taylor

The Bureau of Mines has determined the heat capacity and enthalpy values for beryllium sulfate (BeS04) throughout the temperature ranges of 10° to 300° K in an adiabatic calorimeter, and 350° to 860° K in a Bunsen-type ice calorimter, The heat-capacity data were extrapolated to 0° K, and smooth values of heat capacity, entropy, enthalpy function, and free-energy function were reported at 10-degree intervals between 0° and 300° K. The method of least squares was used to fit the enthalpy data with an algebraic equation. The equation also was used to calculate values of heat capacity, entropy, enthalpy function, and free-energy function at 50-degree intervals between 300° and 900° K.

Jan 1, 1963

By M. J. Ferrante

Low-temperature heat capacities and high-temperature enthalpies for syn¬thetic Cu2S and CuS were measured. This investigation is part of the Bureau of Mines goals to provide thermodynamic data essential to the more efficient processing of copper ores, and thereby minimize the current dislocations in energy, environment, and mineral supply. Heat capacities were measured with an adiabatic calorimeter from 5 to 310 K, and resulted in S°298 = 27.76 for Cu2S(c) and S°298 = 16.05 cal/deg mole for CuS(c). Low-temperature values are tabulated for Cp°, S°, -(G°-Ho°)/T, and H°-Ho°. Enthalpies were measured with a copper block calorimeter from 298.15 to 1,600 K for Cu2S(c,1) and 298.15 to 780 K for CuS(c). The thermal behavior of CuS showed no transitions or other significant anomalies for the low- or high-temperature investigations. Cu2S showed reversible transitions at 376 K with an isothermal heat absorption of 0.865 kcal/mole, 720 K with an isothermal absorption of 0.280 kcal/mole, and approximately 1,400 K (congruent melting point) with a heat of fusion of 3.070 kcal/mole. High-temperature data are tabulated for H°-H°298, Cp°, S°, and -(G°-H°298)/T. Enthalpies are also expressed in equation form. The low¬and high-temperature data were combined with data from the literature to cal¬culate and tabulate ?Hf°, ?Gf°, and log Kf as a function of temperature.

Jan 1, 1978

By Michael R. Yenchek

The U.S. Bureau of Mines investigated the operational characteristics of spliced portable power cables. This research had a dual purpose: (1) to determine the thermal and mechanical performance of repaired trailing cables and compare them with undamaged cables and (2) to gauge the impact of long-term, localized heating on the insulating and jacketing materials contained in cable splice kits accepted or approved by the Mine Safety and Health Administration. The ranges of splice joint resistance and tensile breaking strength were determined from laboratory measurements. The choice of crimping tools affected the strength of the splice under tension. Thermal profiles of energized spliced cables were constructed, which showed that spliced conductor joints operated 5 to 20°C hotter than the intact cable at rated currents. Accelerated life tests of thermally aged samples of splice kit insulation and jacket materials confirmed a deficiency in the thermal rating of the insulating tape. The recommendations in this report may be utilized to revise splice kit design, splice kit approval criteria, and trailing cable loading guidelines. Characterizing the thermal operating limits of spliced trailing cables may help to minimize the associated risks from explosions, fires, personnel burns, and shock.

Jan 1, 2010

By M. D. Schlesinger

As part of the development of processes for producing synthetic fuels from coal, the Bureau of Mines prepared a special jet fuel in a pilot plant for evaluation by the Air Force. This jet fuel had all the required physical properties, including the important specifications of high heating value and high density. However, the finished fuel did not pass the stability test specified by the Air Force and conducted by the Southwest Research Institute in a high-temperature research coker. The cause for this instability is being investigated because pure compounds of the type identified in this fuel are known to be stable. The tar acid oil used was a 230° to 300° C. fraction of low-temperature tar obtained by carbonization of a West Virginia bituminous coal in the pilot plant of the Consolidation Coal Co. Both the desulfurization at 400° C. and saturation at 300" C. were done in the vapor phase at 2,500 p.s.i.g. After catalytic treatment and distillation the final jet fuel had a boiling range of 194° to 247° C., a net heating value of 18,420 B.t.u./lb. and a specific gravity of 0.8463 60° F./60° F. It also had u pour point below -62° C., and at 0° C. its viscosity was 4.5 cs. The oil was virtually all bicyclic, 41 pct. noncondensed and 56 pct. condensed.

Jan 1, 1961

By Rudolf E. Greuer, Linneas W. Laage, Xinton Chang

The program MFIRE consists of four files MFIRE0 EXE, MFIRE1 EXE, MFIRE2 EXE, and MFIRE BAT The batch file, MFIRE BAT, controls the operation and cooperation of the three executable pro¬gram files and the output Networks of up to 500 air¬ways and 350 junctions can be modeled in the PC version of MFIRE Larger data sets can be accommodated by increasing array dimensions and compiling the program again. Input for MFIRE is in the form of a data file The data file contains fines of numerical data describing the physical mine, the ventilation parameters present, the fans, and the proposed thermal or mechanical disturbances

Jan 1, 1990

By Thomas M. Barczak

This report describes a study that examined load transfer mechanics in longwall shield supports as part of the Bureau of Mines research program to optimize support design and utilization. The objectives of this study were to determine the contribution of the leg cylinders and the caving shield-lemniscate assembly towards full shield vertical and hor-izontal load resistance capability and to determine how the interaction of these members affect overall shield response. Load-displacement characteristics of the leg cylinders and the caving shield-lemniscate assembly, independent of the full shield, were evaluated from controlled displacement tests in the Bureau's mine roof simulator and responses were compared with full shield responses to identify load transfer mechanics. It is concluded from this research that the participation of the caving shield-lemniscate assembly significantly affects the response of the shield support. It is likely that the caving shield-lemniscate assembly is not participating fully in current shield designs because of translational freedom in the numerous pin joints. It is also concluded that the shield will respond differently to different boundary condi-tions resulting from interaction with the strata. This report describes load transfer mechanics of shield supports and the implication of these research findings on shield design and utilization.

Jan 1, 1988

Occupational illnesses are more difficult to identify than on-the-job injuries. Many illnesses related to occupational exposures may not be diagnosed until years after exposure; by that time, exposed workers may have changed jobs or left the workforce. Other approaches to identifying occupationally related illness are analysis of death certificate data (see chapter 2) and medical examination studies of workers known to have high exposures to hazardous agents. Figures 5-1, 5-3, 5-4, 5-6, 5-8, and 5-10 show, for each commodity, the percent of illness conditions reported to MSHA by nature of condition. Heart attacks that occurred on the job are reported without regard to work-relatedness. Figures 5-2, 5-5, 5-7, 5-9, and 5-11 show rates by year during 1986-1995 for selected conditions. Since there are many limitations on the accuracy of illness reporting, the frequencies and rates shown here should not be considered directly comparable across commodities. Figure 5-12 shows estimates for hearing loss by age among coal miners compared to a nonoccupationally noise-exposed population. These data come from a study by Franks [1996] of a group of audiograms obtained on coal miners by a commercial company. Using the NIOSH definition of hearing impairment, i.e., an average hearing threshold level for both ears that exceeds 25 dB at frequencies of 1,000, 2,000, 3,000 and 4,000 Hz, the figure shows that by age 30, more than 10% of miners suffer hearing impairment; by age 50, 90% of miners have hearing impairment. In contrast, only 10% of the nonoccupationally noise-exposed population suffer hearing impairment at age 51, and 50% of the nonoccupationally exposed population have hearing impairment at age 69. Figure 5-13 shows a similar analysis of commercial audiograms on male metal/nonmetal miners [Franks 1997]. At age 20, approximately 2% have hearing impairment using the NIOSH definition of hearing impairment described above. This increases to 7% at age 30, 25% at age 40, and 49% at age 50. In contrast, only 9% of the nonoccupationally noise-exposed comparison population have hearing impairment at age 50. Franks' analysis showed a different pattern for female metal/nonmetal miners; they developed hearing loss at the same rate as would be expected for a non-noise-exposed female population.

Jan 5, 2000

By Doris M. Hyde

The impact of mining activities on the economy in both 1983 and 1984 was minimal. The most recent available data on the gross domestic product (GDP) indicated a level of $1.6 billion in 1983.2 The estimated value for the production of cement, aragonite, and salt was about $17 million in that year, down from the estimated $20 million in 1982. No data are available on the economic impact of the large petroleum refinery at Freeport on Grand Bahama Island, but it represents the major mineral-related activity. Cement production remained at only a fraction of the 800,000 tons per year of plant capacity. The offshore search for hydrocarbons continued in 1984, and some companies were about to enter the third year of seismic and geological surveying around Andros and Grand Bahamas Islands. Getty Oil (Bahamas) Co. Inc.; Breoco Ltd., a subsidiary of REO Development Corp. of Tulsa, Oklahoma; and Natomas Petroleum (Bahamas) Ltd. were the first companies to be awarded exploration licenses. These companies were committed to drilling at least one well before the end of the third exploration year. Other companies actively engaged in exploration included Exxon Corp., Atlantic Richfield Co. (ARCO), Chevron Oil Bahamas Ltd., and Esso Oil Bahamas Ltd. Geophysical Services Inc. (GSI) of Dallas, Texas, and Petroleum Services (Bahamas) Ltd. of Englewood, Colorado, ran another seismic survey line during 1984. This 1,533-mile line was in the Great Bahama Bank and Cay Sal Bank areas off the southeast Florida coast, and tied in with a 4,530-mile program GSI ran in 1981-82. These surveys were nonexclusive and publicly available through GSI.

Jan 1, 1986

By Ronald S. Conti

This paper describes technology and training that has been identified for underground emergency responders. Historically, underground mine rescue teams have only received training in the course of actual emergencies, or in simulated mine environments, usually on the surface, with placards to identify objects and hazards. Also, while U.S. Federal Regulations require all underground miners to walk escapeways and conduct fie drills every 90 days in a smoke-free environment, this does not fully prepare them for the conditions that will be encountered in real escape situations. Therefore, it is extremely important that miners are provided with adequate technology and that training simulations are conducted in a realistic manner. A series of mine rescue training and mine emergency response development (MERD) exercises, and in-mine smoke training was developed, conducted, and evaluated by state and company teams, and by National Institute For Occupational Safety and Health (NIOSH) personnel. The training exercises were held at NIOSH's Lake Lynn Laboratory (LLL) and operating mines during the past several years. This training resulted in improved technology and training for mine rescue teams, fire brigades, first responders, and miners in general. For example, existing technologies were identified to help responders during exploration and recovery operations. These included various chemical light shapes, strobe lights, light vests, and laser pointers to identify team members. Most of these devices may be used to mark underground areas and certain mine materials. Strobe lights were used for mapping out escapeways and lasers were used to negotiate travel through smoke. Thermal imaging systems allow rescue personnel to see in darkness and through dense smoke, and allows the user to easily locate missing or trapped personnel and heated areas. A hands-free communication system showed potential for enhanced communications between team members, the fresh air base, and command center. A new team lighted-lifeline allows for flexibility in movements of team members during routine tasks and allows them to easily find their fixed position on the lifeline. Of all the technology evaluated by underground personnel, laser lights and lifelines were most beneficial in leading personnel to safety and out of the mine in smoke-filled passageways. A positive-pressure inflatable escape device (IED)/airlock, was used to isolate the "hazardous" environment from fresh air and allow rescue team members to traverse through. An inflatable feed- tube partition that can rapidly block large openings such as underground passageways or tunnels and simultaneously provide a feed-tube for high-expansion foam generators was also deployed during the simulations. These technological advancements have improved the state of readiness for rescue personnel and have increased the chances of survival for all personnel escaping from underground emergencies.

By Michael D. Fenton

Bauxite resources were primarily in Africa, Asia, Oceania, and South America. Only five countries combined, Australia, Brazil, Guinea, India, and Jamaica, contained most of the total world reserves available for extraction under current economic conditions and accounted for nearly 80 % of world production of bauxite. World bauxite and alumina production declined and prices for smelter-grade alumina remained below the $200/mt level during 1993 because of growing aluminum inventories on international markets and declining worldwide demand. The United States imported bauxite primarily from Australia, Brazil, Guinea, and Jamaica. U.S. alumina plant capacity remained essentially unchanged throughout 1993, but apparent capacity utilization decreased by the close of 1993. Chromium Most of the world's known resources and reserves of chromite are located in India, Kazakhstan, South Africa, and Zimbabwe. India, Kazakhstan, and South Africa accounted for 73 % of world production of chromite. The two largest producers of chromite, Kazakhstan and South Africa, were in the process of major economic and political change during 1993. South Africa's production and exports of chromite continued to fall during 1993, because of weak international demand and a flood of cheap metal from the former U.S.S.R. and China into world markets. Despite a significant increase in production, South Africa's ferrochrome producers continued to operate below capacity in 1993. Prior o the dissolution of the U.S.S.R., Kazakhstan was a major internal supplier of chromite ore to the U.S.S.R. consumer, but subsequent decline in demand led to a downward trend of chromite production in Kazakhstan and increasing exports to Europe during 1992 and 1993. The United States consumed, about 10% of world chromite ore production in various forms of imported materials. The United States imported nearly one-half of its required chromium contained in chromite ore and chromium ferroalloys and metal from South Africa; the remainder was from the minor producers Turkey, Yugoslavia, Zimbabwe, and others.

Jan 1, 1995

By Michael J. Pazuchanics, Thomas J. Fisher, John J. Sammarco, Jeffrey H. Welsh

This report (An Introduction to Safety) is the first in a nine-part series of recommendations addressing the functional safety of processor-controlled mining equipment. It is part of a risk-based system safety process encompassing hardware, software, humans, and the operating environment for the equipment's life cycle. Figure 1 shows a safety framework containing these recommendations. The reports in this series address the various life cycle stages of inception, design, approval and certification, commissioning, operation, maintenance, and decommissioning. These recommendations were developed as a joint project between the National Institute for Occupational Safety and Health and the Mine Safety and Health Administration. They are intended for use by mining companies, original equipment manufacturers, and aftermarket suppliers to these mining companies. Users of these reports are expected to consider the set in total during the design cycle. • 1.0 Safety Introduction.—This is an introductory report for the general mining industry. It provides basic system/software safety concepts, discusses the need for mining to address the functional safety of programmable electronics, and includes the benefits of implementing a system/software safety program. • 2.1 System Safety and 2.2 Software Safety.—These reports draw heavily from International Electrotechnical Commission (IEC) standard 61508 and other recognized standards. The scope is "surface and underground safety mining systems employing embedded, networked, and non-networked programmable electronics." System safety seeks to design safety into all phases of the entire system. Software is a subsystem; thus, software safety is a part of the system's safety. • 3.0 Safety File.—This report contains the documentation that demonstrates the level of safety built into the system and identifies limitations for the system’s use and operation. In essence, it is a "proof of safety" that the system and its operation meets the appropriate level of safety for the intended application. It starts from the beginning of the design, is maintained during the full life cycle of the system, and provides administrative support for the safety program of the full system. [ ]

Jan 4, 2001

By H. H. Fields, Stephen Krickovic, M. G. Zabetakis, Albert Sainato

The Bureau of Mines is in the process of degasifying a virgin area in northern West Virginia from the base of an 839-foot -deep vertical borehole. An in situ gas pressure hole 199 feet long, and seven degasification holes ranging in depth from 500 to 850 feet (average 618 feet) were drilled in an 8-foot-thick virgin Pittsburgh coalbed from the enlarged (14-foot-diameter) bottom of this borehole. The in situ pressure at the back end of the hole and the range of gas and water flows from degasification holes as they were completed and closed off were 203 psi, 79,000 to 257,000 cfd (average 160,000 cfd), and 5 to 8 gpm per hole (average 6.8 gpm), respectively. Twenty-four hours after the seven holes were connected through individual water traps to a common collector for natural venting of the gas through pipes to the atmosphere, the total gas and water flows and the in situ pressure dropped, respectively, to 971,000 cfd, 1.3 gpm, and 18 psi. Eighty days later the corresponding values dropped to 529,000 cfd, 0.50 gpm, and 13 psi. After 180 days of degasification, 91 million cubic feet of gas had been removed from the affected virgin area. This represents 60 to 70 percent of the gas calculated to be contained in the area of coal affected by the holes.

Jan 1, 1973

By Miller, ALEX U, Edward Thomas

In March 1937 the entire country was shocked by news of an explosion of gas in a New London (Tex.) schoolhouse, which resulted in the death of 280 pupils and 14 t eachers. The Government investigators of this disaster believed that the cause was the ignition and explosion of a large volume of explosive natural gas-air mixture that had accumulated in a poorly ventilated space beneath the first floor of the main school building and that this accumulation was due to leakage from gas lin suspended underneath the floor to carry the gas supply to the school.!i/ For some years there has been a potential explosion hazard in school houses and other buildings that are supplied with water from deep wells in certain parts of Illinois. Notwi thstand.ing the disaster at New London, Tex., and the fact that there had been gas ignitions at four water wells in different parts of the State, the explosion hazard in schools and other buildings was not fully recognized until a few months after the disaster in Texas, when an explosion occurred in the settling basin of the municipal water works of Clinton, Ill., and another in a pump house of the municipal water works in Normal, Ill, The explosion in the settling tank of the municipal water works in Clinton, Ill., occurred on August 12, 1937, and a.id considerable damage to the settling tank, but fortunately no one was injured. At the time of this explosion rapairs'and aJ.terations to the water plant were in progress, and 10 men were employed in the immediate vicinity of the settling tank. Two of these men were enlarging a hole in the concrete side with an air hammer for the installation of a larger discharge line.

Aug 1, 1938

The REL of 1 mg/m3 for respirable coal mine dust does not assure a zero risk for the development of occupational respiratory diseases among all miners exposed during a full working lifetime. Consequently, a medical screening and surveillance program that includes initial and periodic chest X-rays and spirometric examinations is important for the early detection of disease and the prevention of "material impairment of health or functional capacity" [30 USC 8 11(a)(6)(A)]. The medical screening and surveillance program is also useful for disease surveillance, which includes the tracking trends, the setting of prevention and intervention priorities, and the assessment of prevention and intervention efforts. NIOSH encourages both underground and surface coal miners to participate in the medical screening and surveillance program.

Jan 1, 1997

By N. F. Le Jeuns

For a number of years the Bureau of Mines has conducted semi-annual surveys to determine the changes in motor gasoline being sold in the United States. It was pointed out in the previous survey that there was an apparent tendency toward greater uniformity in the character of gasoline marketed in the United States. This practically uniform tendency which continued from April, 1917 to January, 1923, has been interrupted in the, present survey, as shown by an examination of the column marked "Difference," as given in Table 1. The figures in this table were obtained by averaging the end points of the least volatile and most volatile samples of gasoline. For example, of 850 samples analyzed in 1919, the 10% ,(85 samples) having the highest end points and the 10% having the lowest end points mere grouped, and the end points of each group averaged. These averages are represented in the table as the "Maximum 10%" and the ?Minimum 10%? respectively. The same process was used on the other surveys.

Jan 1, 1923

By R. E. Mussler

As part of an overall goal to develop technology that can maintain an adequate supply of minerals to meet national economic and strategic needs, the Bureau of Mines is evaluating a method for selectively extracting nickel and cobalt from low-grade domestic laterites. The method involves electrowinning to recover the metals in pure form; therefore, preliminary laboratory-scale electrowinning tests were conducted in both a nondiaphragm and a diaphragm cell to determine the effect of variables on energy efficiency under controlled conditions. Electrolytes were generally reagent-grade sulfate solutions that were prepared to simulate electrolyte that could be obtained by stripping nickel-and cobalt-rich solvent extraction reagents. Limited tests were conducted with electrolyte generated from laterite leach solutions. Electrical energy consumption in a nondiaphragm cell was 2.06 kwhr/lb Ni with the cell operated at 50° C, a cell feed of 90 g/l Ni, a pH of 3.5, an extraction of 3.2 g/l, and a cathode current density of 20 amp/ft2. The energy requirement decreased with increasing concentration and temperature, and increased with increasing. extraction and current density. At 50° C, energy consumption in the nondiaphragm cell was 21 pct greater than in the diaphragm cell, but it was only 5 pet greater at 65° C. For this reason and because of overall cost considerations, operation at 65° C with the nondiaphragm cell was preferred. Smooth sheets of cobalt were obtained by electrowinning in a nondiaphragm cell at selected temperatures from 50° to 85° C and with cobalt concentrations from 55 to 87 g/l. The energy consumption (1.48 kwhr/lb) was 22 pet lower with a cobalt concentration of 75 g/l and a cell temperature of 65° C than with a cobalt concentration of 55 g/l and a cell temperature of 50° C.

Jan 1, 1981

By Philip C. Tully

The Bureau of Mines, in a continuing effort to improve processes and methods of helium purification, has developed a differential distillation method for removing helium-3 from helium-4. Differential distillation at 4.2 to 1.6 K was used to reduce the helium-3 in helium-4 from about 200 to less than 1 part per billion. The results from four stills ranging in size from 1 to 25 liters are reported. The method has the potential to be adapted to commercial-scale separations.

Jan 1, 1975

By H. V. Makar

Ferrous fractions recovered from urban refuse were tested by the U.S. Bureau of Mines, U.S. Department of the Interior, to assess their character, composition, and response to detinning. This research was conducted as part of the Bureau's efforts to conserve mineral resources through recycling. Results from laboratory and pilot tests established the technical feasibility of detinning scrap recovered from household refuse. Detinned products containing less than 0.03 percent residual tin were produced. Concentrations of other residual elements were determined and compared with those in existing commercial scrap and with proposed specifications. Studies were extended to include evaluations under commercial conditions. Preliminary tests on 5-1/2 short tons of ferrous fractions revealed the need for adequate shredding to assure optimum metal-caustic contact and minimize retention of tin-bearing rinse solution in the final baled product. The washed metal product contained 0.06 percent residual tin. Subsequent melt tests showed a yield of 91.4 percent. Based on these studies, full-scale commercial demonstrations showed that detinned bales equivalent to No. 1 bundle quality could be produced in carload quantities. Up to 5 pounds of tin per gross ton of scrap is con-currently recovered during the detinning process.

Jan 1, 1979

By R. V. Ramani, R. Bhaskar

"One of the primary means of control of health hazards from respirable contaminants in mine atmospheres is through design and operation of mines to meet mine health and safety regulations and recommended practices. A U.S. National Academy of Sciences study concluded that for significant progress in coal mine dust control, research should be directed more toward obtaining fundamental understanding of the origin, transport and characteristics of respirable coal mine dust. Theoretical and experimental studies on transport of dust · in mine airways, particularly coordinated efforts to validate theory with practice, are scarce. Some empirical models, developed on the basis of experimental data, are available but these models cannot be applied to new conditions. The purpose of this paper is to present the results of theoretical and experimental studies on the transport and deposition of dust in mine airways. This study is a part of an ongoing research project in the Generic Mineral Technology Center on Respirable Dust.In the paper, the assumptions of the modeling phase of the project and the development of a convectiondiffusion equation for dust transport in mine airways are outlined. The important aspect of the modeling effort is the capture of the deposition phenomenon. The experiments performed under controlled conditions in a typical mine airway, as well as under normal mine operating conditions, are discussed. The comparison of the model predictions with experimental results are made to identify critical areas of agreements and deviations. The implications of the findings and areas for further research and development are presented."

Jan 1, 1990