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By Maria I. De Rosa

Table 1 and figure 1 show the number of fires and fire injuries that occurred in underground metal/nonmetal and stone mines by state during 1990-2001. Table 1 also shows the injury risk rates, employees' working hours, and lost workdays. Overall, 65 fires occurred in 20 states; these include 2 fires and no injuries for contractors. Six of the fires caused nine injuries. The yearly average was 5.4 fires and 0.75 injury. Forty-one fires with 2 injuries occurred in metal mines, 14 fires with 7 injuries occurred in nonmetal mines, and 10 fires with no injuries occurred in stone mines. The underground mine fires required 25 mine rescue team interventions and 30 mine/section evacuations. The Ewhr value was 260 x 10° hr (Irr = 0.007), and the LWD value was 83. Idaho had the most fires (eight fires and no injuries), followed by Louisiana (seven fires and two injuries), Michigan (six fires and six injuries), and Missouri (six fires and no injuries). Of these states, Michigan had the highest injury risk rate value (Irr = 0.146). Table 2, partly illustrated in figure 2, shows the number of fires, fire injuries, risk rates, employees' working hours, and lost workdays by time period. The number of fires during the six time periods show an increase during the fourth period followed by a sharp decrease during the fifth period and a sharp increase in the last period. The number of fire injuries show an increase followed by a decrease during most of the periods, accompanied by a decline in employees' working hours during most of the periods; an increase is seen during the third and fourth periods. The In values follow patterns similar to those shown by the injury values. Tables 3-8 show the number of fires by ignition source, method of detection and suppression, equipment involved, location, and burning material by time period. Figure 3 shows the major variables related to fires for 1990-2001. Table 9 shows the number of fire injuries per number of fires causing injuries and total fires by year, ignition source, equipment involved, and location.

Jan 1, 2004

By Jeffrey B. Osmint

The Bureau of Mines Information and Analysis Directorate collects worldwide data on virtually every commercially important nonfuel mineral commodity. These data form the base for tracking and assessing the health of the minerals sector of the U.S. economy. The Bureau's data collection activity was instituted by the 47th Congress in an appropriations act of August 7, 1882 (22 Stat. 329), which placed the collection of mineral statistics on an annual basis. The most recent authority fur the Bureau of Mines survey activity is the National Materials and Minerals Policy, Research and Development Act of 1980 (Public Law 96479, 96th Congress), which strengthens protection fur proprietary data provided to the U.S. Department of the Interior by persons or firms engaged in any phase of mineral or mineral-material production or consumption.

Jan 1, 1991

By F. E. Spencer

This Bureau of Mines report provides a complete mathematical description of the algorithm employed by a general multiphase chemical equilibrium program developed particularly for the purpose of studying problems in coal combustion, although the generality of the program will allow its application to any equilibrium system in which an appreciable gas phase is present. When applied to coal combustion problems, the program predicts composition and quantity of slag and unconsumed carbon phases as well as calculates accurately the composition of the gas phase including trace species such as free electrons and ions which are important for predicting electrical properties.

Jan 1, 1973

By C. E. Reistle

[In producing crude oils of paraffin base and of mixed base the producer is often confronted with the problem of preventing and removing paraffin that settles out of oil and accumulates in the well. This paraffin consists of heavy waxes with some sand and asphalt, and varies in. consistency from a soft semifluid wax to hard gummy wax. This problem is by no means a new one as troubles have been encountered with it since the earliest days of the industry. However, with the discovery of the panhandle, Texas, field and other large fields in which extensive troubles have been encountered, the problem has assumed added importance. In new fields the most serious trouble with paraffin is in the flowing wells the paraffin accumulates in the casing and tubing of such wells and unless removed will completely plug the well. This condition also develops in wells which are produced by gas lift, and often presents a serious problem when, this method of producing the oil is used. In older fields paraffin is also deposited on the face of the producing sand that on the walls of the hale or within the interstices of the sand near the hole, and this materially affects the amount of oil that can enter the well.]

Jan 1, 1927

Native asphalt was produced in 1977 by six companies in four States. Leading States were Texas and Utah. Output declined 39% to 1,237,000 tons valued at $18,874,000. Bituminous limestone was produced by Whites Uvalde Mines and by Uvalde Rock Asphalt Co. in Uvalde County, Tex.; by Southern Stone Co. in Colbert. Ala.; and by Barton County Rock Asphalt Co. in Barton County, Mo. Gilsonite was produced by American Gilsanite Co. in Uinta County. Utah, and by Ziegler Chemical and Mineral Corp. in Weber County. Utah. The asphalt was used for streets and roads, and for other purposes.

Jan 1, 1980

By 1928-05-01

"The carnotite ores of Colorado and Utah were the chief source of radium for many years. In the fall of 1922; news of the very rich deposits of radium ore discovered in the Belgian Congo caused almost complete cessation of domestic production. The Congo ore contains pitchblend and a number of alteration products, including the new minerals bequerelite, curite, kasolite, stasite, and dewindite. Reports indicate that a considerable amount of ore containing over 50 per cent U308 has been produced. It seemed certain that radium could be extracted from the Congo ore at a much lower cost than from the relatively low-grade carnotite; and in order to preserve their elaborate marketing organizations, the larger American producers made agreements with the Belgium syndicate to market the foreign product in this country. The price of radium has been held at $70 per milligram. Extraction of radium from carnotite by the usual methods does not appear to be profitable at that price. With one exception, all American firms ceased production after their accumulated stocks of ore had been treated. The United States Radium Co., which continued to treat carnotite for several years, has recently shut down its plant.Although there is probably a large profit derivable from the treatment of Congo ore, it is not likely that the Belgium Syndicate will meet sufficient competition to cause any reduction in the present quotations. It is not known how long the high-grade ore will last, but when exhausted the price of radium may be expected to advance. According to K. L. Kithil3 it is the opinion of interested parties that, so far as can be forseen, radium will in future years never again be obtained at the present low price.Carnotite contains the valuable element, vanadium, which is not present in the Congo ore. The recovery of-vanadium is an important factor in the cost of extracting radium from carnotite, and under favorable conditions carnotite can be profitably treated for the vanadium alone. Vanadifecous sandstones are found ranging all the way from roscoelite (vanadium mica), containing little or no uranium; to a high-uranium and low-vanadium carnotite. Ores containing 2 per cent or more U308 are classed as radium ore and are sold on the basis of the uranium content, which is proportional to the radium content. Only in exceptional cases have ores been evaluated on the basis of both the radium and vanadium contents, although the presence of vanadium has undoubtedly influenced the price of radium ore."

May 1, 1928

By Doris M. Hyde

To a greater or lesser extent, the economies of the smaller Caribbean Island countries continued to have common problems. These included unemployment, inflation, foreign exchange shortages, trade deficits, and unstable world prices for their exports. Declining prices for petroleum provided some relief from scarce foreign exchange. Overall, the mineral sector remained stable. The Amerada Hess Corp. crude oil transshipment terminal on St. Lucia was completed during 1981. However, there were no shipments during the year. No official reason was offered for the delay in opening the terminal, but it may have been related to the world surplus of crude oil that occurred in 1981. There has been no further action on the refinery, which was to complete the island's petroleum complex. During the first half of 1981, an announcement was made that a second oil transshipment terminal would be built on St. Lucia. The report indicated that the terminal was to be financed by Saudi Arabia and include underground storage. After the original announcement, no further information was made available. This terminal, like the Hess petroleum complex, may have been temporarily postponed because of the crude oil surplus.

Jan 1, 1983

By R. L. Montgomery

The heats of solution of erbium chloride in water and in hydrochloric acid and of erbium oxide in hydrochloric acid were determined. The results reveal a discrepancy of 10.5 kcal. per gram-atom between the heats of combustion and solution of erbium reported in the literature, the heat of combustion being more negative. The heat of combustion of erbium t4)4 and its heat of solution in hydrochloric acid (1, 18) have been reported in the literature. The heat of solution of erbium chloride was determined in two studies (2, 19). The present work was undertaken to check the reported heats of solution of erbium chloride and to determine the heat of solution of erbium oxide in hydrochloric acid. The latter quantity permits the heats of combustion and solution of erbium to be compared for mutual consistency. It was also desired to determine the degree of similarity between the thermochemistry of yttrium and erbium.

Jan 1, 1961

By David E. Siskind

The Bureau of Mines performed a comparative study of nine sites at eight surface coal mines to determine if the presence of near-surface underground abandoned workings resulted in the generation of adverse long-duration, low-frequency blast vibrations. Six of the nine sites had underlying workings, and two had thick layers of low-velocity unconsolidated surface material. Extended seismic arrays were used to identify the vibration characteristics within a few tens of feet of the blasts and also as modified by the propagating media at distances over 1 mile. Production blasts and specially fired single-charge blasts allowed the determination of natural ground frequency and the influence of initiation delay timing. Vibration amplitudes from the production blasts at all sites exceeded historical norms, particularly at the greater distances. This contrasts with the near-normal results from single-charge blasts. Apparently, between-hole time delays were insufficient to separate vibrations from adjacent charges for the low-frequency waves present. Single-charge tests showed that the propagating media produced low-frequency, ground-roIl-type surface waves at nearly all sites. Large blasts at such sites could produce an unacceptable risk of vibration-induced cracks in nearby structures.

Jan 1, 1989

By John J. Henn

Two lime sinter processes for recovering alumina from clay, the double-leach process and the single-leach process, are evaluated in this Bureau of Mines report. In both processes, clay and limestone are mixed and sintered to form calcium aluminate from which alumina is extracted as sodium aluminate by leaching with a dilute solution of sodium carbonate. The pregnant liquor is desilicated, then carbonated to precipitate alumina trihydrate which is recovered and calcined to a,-alumina. The fixed capital costs for plants producing 1,000 tons per day of alumina are $85 million for the double-leach process and $86 million for the single-leach process based on a Marshall and Stevens chemical equipment index of 240.0. Because plant locations are variable with respect to the proximity of clay and limestone deposits, a nomograph is included to determine operating costs at various delivered costs of clay and limestone. For plants at which the delivered cost of clay containing 30 percent A1203 is $2 per ton and the delivered cost of limestone is $1 per ton, the operating costs are $81.04 and $89.87 per ton of alumina for the double-leach process and single-leach pro-cess, respectively.

Jan 1, 1969

By J. D. Marchant

As part of its mission to assure the maximum recovery and use of the Nation's mineral resources, the Bureau of Mines, investigated an improved procedure for producing rare earth-silicon alloys. For example, a charge consisting of 681 grams of mixed rare-earth oxides, 309 grams of ferrosilicon (75 wt-pct Si), and 182 grams of aluminum metal along with a flux consisting of 681 grams of CaO and 45 grams of MgO was reacted at 1,500° C in an induction furnace. Good slag-metal separation was achieved. The alloy product contained, in weight-percent, 53 RE, 28 Si, 11 Fe, and 4 Al with a rare earch recovery of 80 pct. In current industrial practice rare earth recoveries are usually about 60 pct in alloy products that contain approximately 30 wt-pct each of rare earths and silicon. Metallurgical evaluations showed the alloys prepared in this investigation to be as effective in controlling the detrimental effect of sulfur in steel and cast iron as the commercial rare earth-silicon-iron alloys presently used in the steel industry.

Jan 1, 1980

Minimize drilling time in roof bolting. Approach The Bureau of Mines conducted a survey of 34 roof bolting machines used in underground coal mines. Results of the survey indicated that drilling time, bit cost, and respirable dust concentrations and be reduced by using the appropriate bits for drilling, To evaluate bits currently used and to find optimum cutting parameters needed to minimize drilling time, the Bureau tested two bits commonly used in most underground mines on both wet and dry systems. These are the dusthog* and shank type. The dusthog has dust ports in the bit body to remove cuttings. With shank bits, holes in the drill steel do this. Cost of each type is roughly equal. Bolters with dry vacuum systems were tested in the laboratory first. The lab tests were verified by underground tests in several mines. Bolters with low-pressure wet drilling systems were also tested under-ground. Tests concentrated on the effect of rpm, water and airflow rates, heating, wear, bit design and bit type. Lab Results -Dry Drilling Holes were drilled during the laboratory tests using a production model bolter drilling 45-inch-deep holes into mixtures of lime stone and sandstone aggregate. All tests started with new shank and dusthog type bits at 225 and 450 rpm. Thrust was about 6,000 lbs in all tests. Each bit was tested at two airflows, 15 and 25 cfm, airflows which are typical on operating roof bolter bits. Eleven styles of bits were evaluated. On the average, dusthog bits drilled 25% faster than shank types and were always cooler after drilling. The effect of RPM was tested with 5 different bit types. When bit rpm was increased from 300 to 400, drilling rates doubled. With used, well-worn bits drilling time and final bit temperature were more than doubled.

Jan 1, 1986

By Raja V. Rarnani, Robert L. Frantz

"Co-Directors, Generic Mineral Technology Center for Respirable DustEarly in the 1980s, the U.S. Bureau of Mines initiated the concept of the Generic Center, incorporating it into its mining research program, and in 1983, the Generic Mineral Technology Center for Respirable Dust was established. The Generic Center concept was first envisioned by the U.S. Bureau of Mines as a way to bring together the various different scientific, engineering and medical research interests in the respirable dust area to effect a coordinated and efficient organization for advancing knowledge in that field. The result was a combination of the collective talents and skills of more than 100 scientists, engineers, medical personnel and graduate students, through the formation of a consortium of five major research universities, including medical facilities, to perform respirable dust research. The Generic Mineral Technology Center for Respirable Dust consortium comprises The Pennsylvania State University (with its Hershey Medical Center) and West Virginia University (with its Medical Center) as the lead universities and the University of Minnesota, Massachusetts Institute of Technology and Michigan Technological University as affiliates.Although respirable dust-related disease remains the nation's worst industrial hazard, the fundamental understanding of all aspects of respirable dust associated with the mining and milling industries, including the interaction of dust and lungs, has grown significantly over the past near-decade toward the larger effort to reduce the incidence and severity of disease caused by respirable dust. Continued progress toward making the mine work environment cleaner and healthier remains the immediate objective of the Respirable Dust Center.The Respirable Dust Center's research program and technology transfer activities, described in this paper, exemplify the Generic Center concept first envisioned by the U.S. Bureau of Mines. Interdisciplinary and interactive studies continue to result in significant progress toward making mine atmospheres cleaner and healthier."

Jan 1, 1995

By L. R. Burdick

The Smokescope is an instrument recently developed for determining the density of smoke by shade comparison. The instrument is designed so that the smoke is seen adjacent to two shades of gray corresponding to Nos. 2 and 3 on the Ringelmann chart. Data on smoke density are important in the smoke-abatement field. The method that is specified and accepted as standard for smoke-density determination by the majority of city smoke regulations involves comparing the smoke shade with the four shades on the Ringelmann chart as published by the Bureau of Mines.2/ This investigation was made to determine the accuracy and convenience of the Smokescope. It was conducted as a part of the Bureau I s air-pollution work, which includes the study of techniques that will promote smoke abatement. The accuracy of the Smokescope was arbitrarily defined as the difference between the Smokescope determinations and the determinations by the accepted, standard method and was expressed as Smokescope correction. Although the corrections obtained were strictly correct only for the two observers and the Smokescope of the investigation, they indicate what might be expected from any observer who uses a Smokescope with reference shades that duplicate those of the test instrument. The report is devoted largely to the data on Smokescope correction, which were taken from a single stack under controlled smoke conditions. Field work, which was done at various locations with different stacks, is mentioned briefly in connection with the comparison of the convenience of the two methods. The data for estimating Smokescope correction were taken for the three variables that were expected to affect the results, namely, the density of the smoke, the amount of light, and the color of the sky behind the smoke.

Jan 1, 1955

By John Ward Smith

The Bureau of Mines derived equations expressing the theoretical relationship between density of oil-shale rock and its organic content. Effects on theoretical shale density produced by variations in mineral composition and organic matter properties were evaluated. The theoretical relationship was extended to relate oil-shale density to oil yield in both oil weight and volume units by considering the fraction of organic matter converted to oil and the specific gravity of the oil produced. Corollary equations relating organic content by volume to organic content by weight and to oil yield were developed. The general relationships apply to an oil-shale deposit uniform in character. Application of the theoretical relationships to Green River Formation oil shales was demonstrated.

Jan 1, 1969

By Ann G. Kim

Samples of gas were obtained directly from the coalbed during drilling of horizontal and vertical boreholes in six different formations. The samples were analyzed by gas chromatography for C1 to C5 hydrocarbons and for 02, H2, H2, He, and C02. Methane in the gas varied from 63 to 99 percent; carbon dioxide from 0.1 to 15 percent. The CH4 /CO2 ratio varied and showed no apparent correlation with age, rank, or bed. The majority of samples contained ethane, propane, and butane; hydrogen and helium were found in some samples. Oxygen and nitrogen were usually present, possibly as a result of air contamination. A more extensive sampling program would be necessary to establish relationship between the amount and composition of the gas in the coalbed and other factors.

Jan 1, 1973

By Harold F. Unger

The Bureau of Mines conducted drilling experiments in the laboratory with a commercially available percussive drill that has an independent rotational system. Eight rock types with a wide range of physical properties were drilled under several combinations of rotational speed, drilling thrust, and operating pressure. Penetration rates and energy per unit volume correlated well with the coefficient of rock strength as shown graphically. Size-distribution analyses of some of the drill cuttings show how particle size varies with rotation speed and rock hardness. In general, changing the rotational speed has a greater influence on the penetration rate in softer rocks, with penetration rate increasing with increasing rotational speed.

Jan 1, 1972

By J. A. Eisele

As part of its goal of maintaining an adequate supply of minerals to meet national economic and strategic needs, the Bureau of Mines has studied the removal of iron from simulated aluminum nitrate leach liquors by solvent extraction. Iron must be removed from aluminum nitrate liquor produced by leaching calcined kaolinitic clay with HN03 to reduce the iron level in alumina to less than 0.02 wt-pct Fe203 for use in reduction cells. The parameters reported are for (1) extracting iron from a feed containing 1.5 g/l Fe with di(2-ethylhexyl) phosphoric acid (EHPA), (2) stripping loaded organic phase with 20-pct HCI, and (3) water washing of loaded and stripped organic phase. Recommended operating conditions are two extraction stages using 15 vol-pct EHPA in kerosene and three stripping stages using 20-pct HCI. Results are also given for tests using other extractants and stripping agents.

Jan 1, 1982

By Michael J. Brnich

Since 1991, Pittsburgh Research Center (PRC- formerly part of the Bureau of Mines) researchers have recorded extensive interviews with 30 individuals who are experts in the area of mine emergency response. These individuals, who have an average of 35 years of mining experience and 29 years of mine emergency response experience, related stories and observations from events that they experienced during their combined 850 plus years in mine emergency response. The purpose of this effort was to gather information that could be passed onto both today?s and tomorrow?s mine emergency responders to train and guide them in handling future events.

Jan 1, 1997

By Fred Baldassare, Marcia Harris, Kenneth K. Eltschlager

Surface mine blasting was recently investigated as a potential source of high concentrations of stray gases found in nearby residences of western Pennsylvania. In one incident carbon monoxide was detected in a home and in the other, high concentrations of carbon dioxide were found in a home. Both carbon monoxide and carbon dioxide are by-products of blasting. However, other potential sources of these gases may also exist in a residential setting. In each case, gas chromatography (GC) and carbon isotopic analyses were used to define atmospheric concentrations inside the homes, and to determine the source of a stray gas. Molecular and isotopic analyses provide geochemical evidence as to the origin and source of the stray gas. This paper discusses elements of a stray gas investigation and the analyses necessary to identify the source of a stray gas.