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By G. W. Birge, D. E. Wolfson, J. H. Lynch

Fourteen coal samples representing the Flag , Fire Clay , Whitesburg , Amburgy , Upper Elkhorn No. 3 , Upper Elkhorn No. 2 , Upper Elkhorn No. 1 , and Lower Elkhorn beds in Letcher County , Ky . , were carbonized by the Bureau of Mines - American Gas Association ( BM- AGA ) method , and yields of products and physical properties of cokes were determined . The samples tested were high- volatile A bituminous in rank , with dry , mineral - matter- free fixed - carbon contents ranging from 55.3 to 62.2 percent . Five of the samples , as received , were chemically unsuitable for metallurgical use because of excessive ash and/ or sulfur content . Generally , strength indexes of the cokes were low and all of the coals would require blending with higher rank coal to obtain satisfactory blast furnace fuel .

Jan 1, 1964

By R. D. Dey, V. Castranova, J. M. Antonini, J. A. Blackford Jr.

Alveolar macrophages (AM) exposed to cytokines or bacterial lipopolysaccharide (LPS) produce the free radical nitric oxide (NO·) by an inducible nitric oxide synthase (iNOS). They also release reactive oxygen free radicals following exposure to silica dust. The purpose of the present study was to determine whether NO· is produced by rat AM and/or recruited leukocytes following the intratracheal (IT) instillation of silica. Male Sprague-Dawley rats (175 to 225 g) were IT instilled with either silica dust (10 mg/100 g body wt) or LPS (0.25 mg/100 g body wt). After 24 h, bronchoalveolar lavage cells (BALC) and lavaged lung tissue were assayed for iNOS mRNA. Cell counts of BALC and iNOS-dependent (Nw-nitro-Larginine methyl ester [L-NAME]-inhibitable) chemiluminescence generated by AM were also determined. Northern blot analysis demonstrated that the steady-state levels of BALC iNOS mRNA were significantly increased by 3-fold following IT silica and by 7-fold following IT LPS. Partially enriched fractions of either AM or leukocytes from silica-treated rats both exhibited significantly elevated iNOS mRNA in Northern analysis. iNOS-dependent chemiluminescence was significantly increased in AM by 36-fold following IT silica and by 89-fold following IT LPS. Differential counts of BALC showed that AM numbers did not change in any of the treatments; however, red blood cells increased by 30-fold following IT silica and by 23-fold following IT LPS. Total leukocytes (polymorphonuclear leukocytes plus lymphocytes) increased by 58-fold following IT silica and by 274-fold following IT LPS. The results demonstrate that AM and neutrophils iNOS steady-state mRNA levels, AM iNOS-dependent chemiluminescence, and lavagable red blood cells and leukocytes all increased following IT silica. These findings suggest that NO· production in rat AM and neutrophils is increased in response to silica. NO· has the ability to then combine with superoxide and form a highly reactive toxic species, peroxynitrite, which may be responsible in part for silica-induced lung damage.

Dec 1, 1995

By Joseph M. Pugliese

The Bureau of Mines through its contract research program recently analyzed the mining and environmental requirements in the premining stage for copper mining in the northern highland of Wisconsin. The Critical-Path-Method (CPM) was used in this research. However, a step-by-step derivation of the CPM Diagram was beyond the scope of this effort. The Bureau of Mines objective now is to show, step by step, how the original hand-computed CPM Diagram was constructed. The streamlining (restructuring) of this diagram from the original effort is also summarized. The critical path time (longest time) through the original CPM Diagram was 25.12 yr, excluding public liaison effort. This diagram showed the involvement of the regulatory agency, mining applicant and public in the premining stage. Analysis of this diagram produced a streamlined version which reduced the critical path time by nearly 7 yr. The CPM construction methodology offered here may be applied to mine planning for any mining operation.

Jan 1, 1983

By J. S. Kennedy, R. G. Omeara

Beryllium is a strategic metal of ever-increasing peacetime importance because of the unusual properties of beryllium-copper alloys. These unusual characteristics are the combination of high strength and hardness, high fatigue resistance, and high wear resistance in alloys that have the corrosion resistance of copper. The principal industrial source of beryllium is the mineral beryl, a beryllium-aluminum silicate that occurs in pegmatites associated with quartz, feldspar, mica, and smaller amounts of various accessory minerals. The beryl is usually recovered in processing the pegmatites for the recovery of some of the other mineral constituents. Pegmatite deposits are found in various parts of the United States, but those in the Black Hills of South Dakota are the source of most of domestic production. The beryl marketed from the South Dakota pegmatite deposits occurs as coarse crystals, which are obtained by hand sorting. These pegmatites also contain other valuable minerals.

Jan 1, 1948

Southeast Alaska's mining industry has come to life after nearly 50 years of relative dormancy. Commencement of operations of the Greens Creek Mine in 1989 marked a turning point in the industry as the first large scale mining operation in the region since closure of the Alaska-Juneau Mine in 1944. The Greens Creek Mine is now the nation's largest silver producer. Other large scale mining projects are now on the drawing board, including development of the Kensington Mine and reopening the Alaska-Juneau Mine, which could become North America's largest underground gold mine. The region's mining industry includes more than these large scale projects, however. For example, a significant level of mineral exploration occurs each summer in Southeast Alaska. In addition, mining operations in British Columbia and Yukon Territory are generating jobs and income in Southeast Alaska.

Jan 1, 1992

By R. J. Matetic

The Bureau of Mines, as part of a program to improve mine planning and development, is currently investigating the effects of pillar load transfer, which can impact mining operations within a multiple-seam configuration. A comparative study was performed at two separate mine sites. The objective of this study was to compare two mines, each affected by this pillar load transfer mechanism, and to show how this interaction affected underground workings by the installing and monitoring underground instrumentation. At mine site A where the overburden was 1,000 ft, the innerburden thickness was less than a pillar width (40 to 45 ft), overlays of the mine layout show pillars were not superpositioned, excessive roof to floor convergence was measured, and pressure readings indicated pillar core loading only. At mine site B, the overburden was approximately 555 ft, the innerburden thickness was approximately 105 ft, overlays of the mine layout show pillars were superpositioned, minimal roof to floor convergence was measured, and pressure readings indicated a skin loading only.

Jan 1, 1988

By A. L. Engel

Production of chromite in California has been from many small, high-grade mines. The opening of the Purchase Depot at Grants Pass, Oreg., in 1951 has stimulated chromite mining in California, and a large number of properties are being reexamined as there is a possibility that some low-grade ores from many of these properties can be beneficiated to meet the purchasing schedule. The Bureau of Mines in its program of conservation is continuing ore-dressing tests on chromite ores to better evaluate their potential. This report is a compilation of preliminary concentration tests on samples from five different properties in California. The concentration tests were made on ores from the David mine, Butte County, the Seiad Creek mine, Siskiyou County, the High Plateau mine, Del Norte County, Bud's mine, Tuolumne County, and tailings from the Miller concentration plant in San Luis Obispo County, Calif., to determine the possibility of beneficiating these ores so that they will meet the specifications for the Government stockpile.

Jan 1, 1956

By A. C. Rice

Aminopolyacetic acid chelating agents were added to separatory-funnel-scale solvent-extraction systems to determine the effect on separating rare-earth elements. Average values for separation factors between adjacent elements obtained with Primene JM-T2 increase 36 percent when EDTA is added to the aqueous phase. Adding HEDTA or DCTA also improves separation factors for certain rare-earth elements. Percentage of extraction and the separation factors exhibit marked sensitivity to concentrations of amine, chelating agent, and hydrogen ion. The chelating agents improved separation in Primene JM-T, BHDA, and Primene 81-R extraction systems.

Jan 1, 1963

By Robert L. Rough, William E. Eckard

Laboratory data obtained from a Bureau of Mines rotary air core of a well near Sugar Grove , Warren County , Pa . , were instrumental in initiating hydraulic fracturing in the area to stimulate oil recovery from Glade sand oil reservoirs . This report outlines the general geology , lease development , reservoir- rock characteristics , and oil - production history of Glade and Clarendon sand reservoirs in Warren County . The methods of well completion for single- stage and multiple- stage hydraulic fracturing of old and new wells are discussed , and a range of hydraulic fracture treatment data from 29 Glade sand and 10 Clarendon sand wells is presented . A composite decline curve representing oil - production data from six wells shows probable results of hydraulic fracturing . Average cumulative oil production during the first 100 days after hydraulic fracturing with a sand - carrying liquid is compared with production after conventional shooting with liquid nitroglycerin .

Jan 1, 1964

By John P. Capp

The feasibility of simultaneously burning several paths through a coalbed to develop a multiple path underground gasification system was investigated by the Bureau of Mines during two experiments, Boreholes were drilled through the overburden and into the coal and arranged in a circle approximately 50 feet from a central borehole. In the first experiment, in an area which had previously been hydraulically fractured,5 air was injected at the center borehole. The coal was ignited at the other boreholes and the fire fronts traveled toward the center, counter to the flow of air, to backward burn paths through the coalbed. Two paths were linked during the first 5 days of operation. The outlets of these two paths were throttled and air pressure was increased to maintain the flow of air, but no other linkages were made. Fourteen days after the two linkages these two paths were opened and gasification was carried on for 10 days, but with only moderate success. In an effort to overcome operating difficulties air was injected at the peripheral boreholes, and the gases were drawn off at the center borehole. Reversed flow operations continued for 12 days and two more paths linked. The heating value of the gas generally was higher than 100 British thermal units per standard cubic foot (B.t.u. per std. c.f.). Because only four of seven paths linked, however, the entire system could not be evaluated with respect to product-gas output and recovery of energy.

Jan 1, 1961

By E. R. Bauer

This report presents the results of a cooperative study between BethEnergy Mines Inc., Ebensburg, PA, a central Pennsylvania coal mining company, and the U.S. Bureau of Mines to investigate longwall development entry roof instability. In-mine mapping of geologic and deformational features was conducted to reveal the major ground control problems encountered during gate road development. In addition, mining-induced pillar load monitoring was used to indicate development loading on variously dimensioned gate road pillars and to determine if pillar yielding occurred. Finally, visual observations of a variety of roof control methods were used to determine the most effective support elements for controlling cutter roof failure.

Jan 1, 1992

By E. J. Murphy

The Bureau of Mines developed a fast, reliable modification of the Griess-Ilosvay procedure suitable for field analysis for NO2 in the fumes from explosives. Known concentrations of NO2-air mixtures were analyzed for the nitrous acid or nitrite formed in the reaction with three Griess-Ilosvay-type reagents by diazotizing and coupling. Comparison was made of the Rider-Mellon, Saltzman, and Patty-Petty procedures; the three procedures are in agreement if sufficient time of contact between NO2 and the reagents is allowed. In experiments to obtain an accurate factor for converting NO2 to nitrite, overnight contact was allowed in order to be sure conversion was complete. The factor was found to be 75 percent with a standard deviation of ±3.2. Low and erratic results were found using either the Saltzman or Patty-Petty reagents as absorbing liquids unless several hours' contact was allowed. If dilute NaOH solution was used as the absorbing liquid instead of a Griess-Ilosvay-type reagent, 92 percent of the overnight conversion factor was found after a 3-minute shaking time and a la-minute standby time. The Saltzman reagent was preferable for fieldwork with the dilute NaOH solution as the absorbent because of its easy application, rapid reaction, and intense color even at low NOB concentrations.

Jan 1, 1967

By T. F. Mitchell, J. A. McAllister, S. J. Hussey

"INTRODUCTION During the Bureau's extensive program of investigating possible domestic sources of manganese, an are-dressing study was conducted in its laboratories at Salt Lake City, Utah, on a sample of oxide manganese ore representative of vein material from the Ophir Hill mine at Ophir, Tooele County, Utah. The sample (obtained by blasting down and mixing a portion of the vein) was submitted by the Ophir Development Co. of Ophir, Utah. As the ore was too law in grade to be acceptable for direct production of ferromanganese, it was tested to determine its amenability to concentration by ore-dressing methods.At the beginning of the investigation of manganese-ore beneficiation in December 1940, the only product marketable to Metals Reserve Company was ferrograde manganese, grade B, the requirements for which follow: Mn, min., 48 percent; Fe, max., 7 percent; Si02, max., 10 percent; P, max., 0.18 percent; A1203, max., 6 percent; Zn, max., 1 percent.Later, the specifications were modified gradually. As of May 15, 1943, manganese products were acceptable if they contained over 35 percent manganese and less than 3 percent zinc and 1 percent phosphorus. Prices were based upon material containing 48 percent manganese, 6.0 percent iron, and 11 percent silica plus alumina. Premium were paid for manganese content in excess of, 48 percent and iron content below 6 percent, penalties being imposed upon products containing less than 48 percent manganese or more than 6 percent iron or more than 11 percent silica plus alumina. The specifications for commercial manganese further required that maximum particle size be 12 inches and that 75 percent of the product be coarser than 20-mesh. Therefore, fine material, such as table and flotation concentrates, had to be nodulized or sintered. In addition, carbonate manganese ores were not acceptable unless calcined."

Oct 1, 1947

By Raja V. Rarnani, Robert L. Frantz

"Mining is one of the oldest of human occupations. The awareness of occupational illnesses associated with mining, even in ancient times, is evident from the writings of Hippocrates (460-370 BC), Pliny and Elder (AD 23-79), and Galen (AD 131-210). Georgius Agricola (1494-1535), in his De Re Metallica, refers to the diseases of miners and the need for their control through good planning and operating practices and responsible management (Schwerha, 1989). Coal workers' pneumoconiosis (CWP), often called Black Lung disease, is an occupational disease which results from inhalation of coal mine dust which usually contains relatively small amounts of free crystalline silica.A pneumoconiosis is best defined as the accumulation of dust in the lungs and the tissue's reaction to its presence [Lapp and Castranova, 1993]. Silicosis is the name given to the fibrotic disease of the lungs caused by the inhalation of dust containing silicon dioxide, primarily in the free crystalline form. Silicosis is the older and more well known of these mineral pneumoconioses. In contrast, CWP was not recognized as different from silicosis until the pivotal work of Collis and Gilchrist [1928].The U.S. Bureau of Mines (USBM) still regards worker exposure to respirable aerosols in mines as the most serious health problem in mining [USBM, 1994]. The National Institute of Occupational Safety and Health (NIOSH) is considering recommending a reduction in the standard for occupational exposure to respirable coal mine dust from 2 mg/m3 to 1 mg/m3 [NIOSH, 1993]. The Mine Safety and Health Administration (MSHA) may require new criterion for sampling procedures in the mine that would evaluate the ambient dust concentration in the mine atmosphere based on a single sample, instead of the current practice of averaging five samples (MSHA, 1992; Ramat* 1993). Several high-production longwall mining faces currently have extreme difficulty meeting the existing dust standards, and some already operate at reduced production levels to achieve mandated levels [USBM, 1993]. The importance of adequately protecting the miners from high concentrations of coal mine dust, as well as of reducing the incidence and severity of the Black Lung disease, cannot be overemphasized. The importance stems, first and foremost, from the humanitarian viewpoint and, second, from the perspective of the overall welfare of the coal industry.The histopathologic hallmark of CWP is the coal macule (Balaan, Weber and Banks, 1993). Autopsy or open lung biopsy reveals the coal macule to be an amorphous mass of coal particles, dust-laden pulmonary macrophages, reticulin, and collagen. No pathognomonic signs or symptoms identify workers with CWP. A CWP diagnosis requires that the worker experienced the appropriate dust-exposure setting (e.g., underground coal mining) and duration (usually 10 years or more) and, has the characteristic chest radiograph. Based upon the International Labour Organization (ILO, 1980) international classification, pathologists and radiologists have established case definitions for characterizing the pathology and the appearance of CWP on chest radiography (Weeks, 1993). CWP appears in two principal forms: simple, with small opacities, and complicated, with opacities larger than 10 mm in diameter. For all practical purposes, diagnosis of CWP in the living miner is wholly dependent upon the chest radiograph interpretation."

Jan 1, 1995

By R. W. Dalzell

The performance characteristics, efficiency, and operating pressure of jute line-brattice systems were studied under varying underground conditions; various fabric grades and installation methods were used. The test results indicate that line-brattice system efficiency is dependent upon the method of ventilation the method of installation, porosity of fabric, and size of tight rib area.

Jan 1, 1966

By Jeffrey H. Welsh

The Bureau of Mines studied the use of computerized, continuous, remote monitoring systems for safety from power system faults in underground coal mines. In this report the need to improve protection against power system faults is documented, and types of faults are identified. The relationship between mine safety regulations and computerized, continuous, remote monitoring is analyzed.

Jan 1, 1983

By V. E. Edlund

Laboratory batch flotation tests were conducted on copper converter slags to evaluate the relative merits of recovering copper from slow-cooled versus water-quenched slags. Three slags containing 1.6, 5.0, and 6.6 percent copper were used. More than 90 percent of the copper was recovered in a rougher concentrate leaving a 0.2- to 0.3-percent copper tailings when treating slow-cooled slag. Lower recoveries and higher copper tailings ranging from 0.5 to 0.6 percent copper were obtained from quenched slag. Grindability studies were made on the respective heat-treated slags. Quenched slags proved more difficult to grind than slow-cooled slags. Cost studies showed that quenched slags can be treated at slightly lower cost than slow-cooled slags. However, the cost advantage of processing quenched slags is more than offset by the higher copper recoveries obtained from slow-cooled slags.

Jan 1, 1971

This publication summarizes the research (in-house and contract projects) programmed by the Bureau of Mines for fiscal year 1984 (October 1, 1983-September 30, 1984) under its Health and Safety Technology Program. The objective of these projects is to provide an ordered and sequenced advance toward the Bureau's overall goal of providing the systems technology required to create a more healthful and safer working environment for the Nation's mining and minerals processing workers.

Jan 1, 1983

By J. T. McCartney

In an effort to correlate the size of pyrite particles in coal and coal-particle association with the removal of pyrite before burning, the Bureau of Mines conducted a study of 61 coals presently being used for electric power production. The results were obtained by visual microscopic studies of polished briquets of minus l4-mesh samples. Mean pyrite particle sizes ranged from 20 to 400 microns and proportions of pyrite contained in coal particles to an extent greater than 50 percent by volume (estimated) ranged from 20 to 95 percent. These parameters were correlated with reductions in pyrite accomplished by float-sink tests at 1.60 sp gr on 14-mesh, 3/8-inch, and 1-1/2-inch samples. The correlation coefficients between pyrite removal and mean pyrite particle size were 0.89, 0.84, and 0.79, respectively, for these samples. Correlation coefficients between pyrite removal and coal-pyrite association parameter were 0.92, 0090, and 0.85, respectively. It is apparent that extent of pyrite removal can be fairly well predicted from microscopic analysis.

Jan 1, 1969

Although the technology involved in removing material from below the earth's surface has a long history, communication systems in underground workings are relatively new to the industry. Communication equipment did not begin appearing in underground mines until the early 1900's. Figure 1-1 shows a miner using a Western Electric standard telephone set for underground mines in 1913. These early phones were essentially the same as those used aboveground, except that they were enclosed in cast-iron boxes as protection against moisture, acid fumes, and gases.

Jan 1, 1984