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A Helix Pressure Gauge to Indicate roof bolt loads was designed, fabricated and field tested. The gauge indicated loads between 3,000 and 15,000 pounds with a ± ten per cent error. The coat of fabrication of the gauge was estimated to be $3.39 including an assumed overhead and profit per indicator for a series production of 5,000 unite. The unit can be read on a bolt to within ± 1,000 pounds load from a distance of twenty feet.

Jan 1, 1974

By A. Gene Collins

Some of the geochemical relationships that exist between subsurface fluids and the associated geologic strata in petroleum producing areas of Louisiana have been determined. Samples of petroleum-associated water were obtained from 126 wells in Louisiana that produced from sediments of three geologic ages: Tertiary, Cretaceous, and Jurassic. The samples were trans-ported to a central laboratory for analysis of chemical composition, using standard methods, to determine if the compositions varied with the geologic strata of their source and, if so, why. The dissolved constituents were com-pared with those of a brine that was concentrated by evaporation. The concentrations of bromide, calcium, and strontium were useful in distinguishing the brines produced from sediments of a late age from those of an earlier age. The concentration ratios of Mg' (total equivalent magnesium) and bromide indicated that dolomitization probably had occurred and altered the composition of the brines. A principal-components analysis of the data indicated an inverse relationship between depth and concentrations of bromide, strontium, calcium, and lithium.

Jan 1, 1970

By Roy L. Wilfong

Infrared reference spectra are presented of compounds of importance in lead sulfide flotation research. Included are the spectra of several short chain alkyl xanthates of lead and zinc, the corresponding dixanthogen compounds, and the common oxidation products of lead sulfide and their sodium analogs. The spectra of several frequently used industrial flotation reagent xanthates are also presented. A thorough, well-documented discussion is given of the various corrections made to correct the as recorded absorption band data to near absolute values.

Jan 1, 1974

By J. H. Jansky, P. W. Jeran, G. L. Hassett, M. C. Irani

This Bureau of Mines report tabulates methane emissions from U.S. bituminous coal mines with daily emission rates of at least 100,000 cfd according to States, counties, and coalbeds. Most of the methane emitted is from mines in the Appalachian States. Total daily emissionin 1975 was 216.3 MMcfd, compared with 227.0 MMcfd in 1971 and 214.5 MMcfd in 1973. Thirty counties in nine States had daily methane emissions of 1 MMcfd or more, These emitted 93 percent of the total methane. The highest emissions were from Monongalia County, W. Va,, which accounted for 18.9 percent of the total. This was followed by Marion County, W. Va., 9.6 percent; Buchanan County, Va., 8.5 percent; Jefferson County, Ala., 6.1 percent; and Washington County, Pa., 5.9 percent. The Pittsburgh coalbed emitted 45.7 percent of the total methane, followed by the Pocahontas No. 3 coalbed with 12.9 percent. The report lists 196 mines, of which 60 had daily methane emissions of 1 MMcfd or more. Included in this compilation are the identification and thickness of the coalbed, methane emission, coal production and ventilation rates, number of drifts, shafts, and slopes used for ventilation purposes, shaft depth, age of mine, and gas-to-coal ratio.

Jan 1, 1975

By Frank E. Federspiel

In 1986 and 1987, at the request of the U.S. Forest Service, the U.S. Bureau of Mines examined the 47,000-acre Electric Peak study area (part of the formerly-designated RARE II Non-wilderness Recommended Area no. 1609) to evaluate its' identified mineral resources. The study area is in Powell and Jefferson Counties, YT, about 30 mi southwest of Helena and 30 mi north of Butte. Three lode localities within the study area contain an estimated 159,000 tons of identified subeconomic resources containing gold, silver, and accessory lead, copper, and zinc. Resources at those localities range from 10,000 to 134,000 tons with grades ranging from 0.04 to 0.32 oz/ton gold, 0.92 to 16.42 oz/ton silver, 0.14 to 79.65 percent lead, and as much as 0.41 percent copper and 0.68 percent zinc. One property also contains 0.15 percent antimony. Gold, silver, and base-metal content in samples of poorly exposed mineralized structures indicate that further exploration may identify resources on seven additional study area localities.

Jan 1, 1988

By F. E. Armstrong

Tritiated water has been used as a tracer to follow the path of leach liquids as they flow through a copper-mine dump. Semipermeable layers, produced within the dump by compaction and "stratification" of deposized dump material, restrict the vertical movement of water. Knowledge of this restriction would aid in the optimization of the leaching process. The portion of the dump of particular interest was approximately 2,000 feet long, 800 feet wide, and 200 feet high. A total of 94 curies of tritiated water was injected into the dump at the rate of 650 gpm over a period of 39 hours. The leach liquid was sampled at natural surface outflows and through a series of wells, some drilled to the bottom of the dump and others to intermediate levels. More than 3,300 samples were analyzed, most by liquid scintillation counting, but a few hundred by gas counting. Data obtained permitted calculation of flow paths, recycle times, total fluid volume, and estimates of retention times in various portions of the dump.

Jan 1, 1971

By R. Karl Zipf

In some instances, extensive room-and-pillar working scan collapse with little warning and pose a serious risk to underground miners. Traditional strength-based pillar design methods applicable to coal or hard-rock mines use a factor of safety defined as pillar strength divided by pillar stress. Factor of stability, defined as local mine stiffness divided by post-failure pillar stiffness, may offer a way to design room-and-pillar mines and eliminate collapses. Three alternative design approaches to decreasing the risk of large-scale catastrophic collapses are described: the containment approach, the prevention approach, and the full-extraction approach. Until good data on the post-failure behavior of pillars become available, the containment and full-extraction options are the safest. The limitations in our ability to evaluate both the stability of old workings and the long-term performance of room-and-pillar mines are described.

Control the release of ground-water into active underground coal workings by short-term pumping from dewatering wells sited on fractures. Approach The sudden release of fracture-stored groundwater into underground coal workings often occurs when mine workings are developed beneath fracture valleys, Pumping from fracture trace-sited dewatering wells, prior to development of the underlying workings, can be an efficient means of intercepting fracture-stored groundwater before it is released into the mine. Dewatering operations are discontinued once the underlying mine workings have been fully developed, and the maximum possible reduction in fracture storage has been achieved through pumping. How It Works An aerial photographic technique known as fracture trace analysis is used to site dewatering wells on rock fractures in a valley bottom. Downhole caliper and temperature logs are used to assess the fracture flow potential of each dewatering well drilled.

Jan 1, 1987

By Andrew D. O. O’Brien, Linda J. McWilliams, Joe L. Howell, Douglas E. Pollock, Jeanne A. Zimmer, Andrew B. Cecala

A quick, safe, and effective method has been developed that allows workers to clean their dust laden work clothing periodically throughout the day. For the mining industry, this technique is much more effective than the current federally approved method of using a vacuuming system. This newly designed method is relatively inexpensive and can be easily installed at any operation to allow workers to clean their clothing without contaminating the worker, the work environment. or co-workers to elevated respirable dust levels. This clothes cleaning process uses an air spray manifold to blow dust from a worker's clothing in an enclosed booth, which combines the dust for capture and removal by a baghouse dust collector. Since the air exhausted by the dust collector causes the booth to be under negative pressure. no measurable quantities of dust were ever measure escaping from the booth to contaminate the work environment and/or other workers. The worker performing the cleaning process is required to wear a half-mask fit- tested respirator with an N 100 filter, hearing protection, and full seal goggles. Dust samples taken inside the respirator of test personnel performing the clothes cleaning process showed very minimal to no respirable dust. This clothes cleaning process was performed in less than 20 seconds and was significantly y cleaner than either the Federally approved method of vacuuming, or the most common method or using a single compressed air hose. It was also determined during this research that polyester-cotton blend coveralls clean more effectively than coveralls which are 100 percent cotton. The newly designed clothes cleaning process has potential application to any industry where workers' clothing becomes contaminated with most any type of dust or product.

By Earl R. McMillan

"Coal washing commands the thoughtful attention of a steadily incre in number of people. Clean coal is not merely a luxury but is rapidly becoming a necessity in some industrial operations.Coal seams in the Northeast are rarely free from ""bone"" and shale or clay partings which vary from a fraction of an inch to several feet in thickness. Nearly all of the coal measures are folded and faulted, the coal seams dip at various angles, and in some cases are badly broken. In mining these seams fragments of the roof and floor, as well as partings of impur-ities within the seams, unavoidably become mixed with the coal, so that the raw coal as it comes to the surface often contains as much as 50 per cent, by weight of waste.At the Bureau of Mines experiment station at Seattle, the washing of this coal in order to improve it for commercial use has been studied. Since the process of coal-washing depends upon differences in specific gravity between the clean coal and, its associated impurities, the first problem undertaken was that of determining the specific gravity of the clean coal and of each parting of impurity contained in a large number of representative seams.It was found that the freshly-mined coal is practically saturated with water, this being observed in determining the effect of moisture content upon the specific gravity of the coal particles, selected from samples of coal varying from low-grade subbituminous up to semianthracite, all of which are found in the State of Washington. The specific gravity values determined for the cleanest particles varied from 1.28 to 1.35; in general, the higher the rank of the coal the hither the specific gravity."

Nov 1, 1920

By L. D. Tracy

For many yeirs natural gas has been the principal fuel used in the he·1 ting furnaces in those mills located in the. Pi t-c;s. b.urgh district· \7hich manufacture bolts ., nuts, rivets, pick$, mattocks and srr.&11 for6ine;s. For a nUI.1"'.::>er of years the steady supply of this fuel has been more or less interrupted owing to the increased4and f·or d9mes tic use and to the increasing difficulty in securing an ad.eq_ua te c.1mount of natural gas. This condition has led a number of the steel compa.nies to substitute -oulvsrized coal a.s a fuel for the.furnaces. Elaborate irista.llations have been made for pulverizing tne coal ar!d _ coriveyi16 i -c to the fur:waces. • Soon after the furnaces ·-:commenced .. to operate ·,Vi th :pulverized coal, large quanti ties O::f.' fine dust beg.::in to accumulate on the platforms over the fu:rna. ces, the. roof trusses, on the outside of the va.rious· pip·e ·line electric cables a.i.1.d even on the roofs of the buildings. Some of tha comi:,a.n:;.0s, becomin·g alarmed, requested the Bureau of ;Unes to rr.c1ke an investigation to ascertcliin the.· licibili ty of this dust to cause an explosion.· Nhi le conducting this inves ti ga ti on,· an explosion· occurr-2! d in a.nothe:2 nill ·,7hich caused he death of one man and severely burned t;io others. Eleven sc1nrcles of the dust (which for convenience has been termed "mill d.ust 11 ) from various locations in the different mill' buildings were taken and submitted to chemical analyses, microscopic examination and also to flame and explosion tests. From the chu,1ica.l analyses it was found that· the volatile matter in th..:: dusts xanged -from 6.3 per cent to 23,54 per cent, fixed carbon from 50.88 per cent to 67.08 per cent and ash from 32.29 per cent to 32.16 per centw

Dec 1, 1919

By D. M. Soboroff

Etchants containing hexavalent chromium and sulfuric acid are used in a variety of surface-finishing operations. When the resultant spent solutions are discarded, substantial quantities of chromium are lost and pollution prob¬lems are created. To minimize the undesirable environmental effects while improving metal and minerals recycling technology, the Bureau of Mines is conducting research on a method for the economic inplant recycling of these waste etchants. Trivalent chromium, produced when the etchant reacts with a sub¬strate, is oxidized in the anode chamber of a diaphragm cell; other metals, dissolved during the etching operation, are transferred to the catholyte. When waste brass etchants are treated in this manner, all of the trivalent chromium is oxidized and more than 40 percent of the copper and zinc is removed. Similar copper removal and chromium oxidation are achieved with waste printed circuit board etchants and rinse waters from plastic etching operations. The electrical energy needed to regenerate 1 kg sodium dichromate is less than 9 kwhr. Regenerated brass etchants evaluated by two companies equaled or exceeded the performance of fresh etchants.

Jan 1, 1979

By Thomas V. Falkie, R. Venkataramani

Table

Jan 1, 1972

By Wallace W. Roepke

The Bureau of Mines has a well-established health and safety research effort directed to fundamental studies of the mine cutting system. This report describes the ignition danger of using cutting bits with flat wear area on still-intact carbide inserts.

Jan 1, 1983

By Raymond B. Ladoo

Cne of t·: . .:: i::,portt recent developrr.ents in the feldspar industcy l:.a.s beer. tl:.e r,:ipid. rise of Ne·N H.v-:psr.ire as a. feldspar producing State. Tl:.e unusual size and purity of t: e deposit now 'being worked ne3.r Keene, and tr.a i.nproved metl:.ods ot:' rr.ining srd ir,illing used l:.ave been responsible foe tt.is situation. ti'eldsp'.:l. w'ls occ':tsiona.lly produced sorr.e ye1rs ago in srr.a.ll (tuantities in New Hrunpshi :e, but t::.e State had not been considered a producer of" feldspar ui til lS3l. In the s::ring of tr .. at yea!', t:.e '[eane iic Products co. of Keene, N.H., beg3Il in a srr.9.ll way tl:e production of feldspar fro:n t1eir property in Gilsum, H.H., whicr. l-.a.d long been opera.tei a.s a :tl.ca mine. The purity of the feldspar at enoe '\ttracted f''.lvorai)le attention. and tt.e production of crude ore rapidly in­ cre'.\sed. Early in 1922, a new company, t'he Golding-Keene Co,

Sep 1, 1922

By A. T. Iannacchione, D. G. Puglio

This Bureau of Mines study covers 25 underground mines that were active in the Upper and Lower Freeport and Lower Kittanning coalbeds in 1976. The coal ranges from low to medium volatile in rank; its primary use is for steam generation. Seven mines emit more than 100,000 cfd of methane gas; those mines are the deepest and largest producers. The methane gas content of three core samples of the Lower Kittanning coalbed was estimated by the direct method. A sample from a depth of 320 feet contained 0.5 cu cm of gas per gram, at 620 feet there was 0.8 cu cm of gas per gram, and at 1,060 feet there was 11 cu cm of gas per gram. These results suggest that methane control problems will be encountered in the future as deeper coal is mined.

Jan 1, 1979

By D. Eugene Rannels, Yu-Chen Lee, John W. Swisher

"Inhaled dust particles of appropriate size contact cells of the alveolar region.' The acute response to coal dust appears to involve a variety of cell types, including alveolar epithelial cells, interstitial fibroblasts, both resident and recruited macrophages, and cells of the immune system. Direct and indirect effects of dust, which may be mediated by soluble factors,'' can initiate acute and long-term lung injury. While it appears that epithelial cell growth and differentiation, along with integrity of the epithelial basement membrane, may play a role in the long-term response to dust exposure, little is known of the role the alveolar epithelium may play in the progression of injury. The broad hypothesis that underlies these experiments is that short- and long-term consequences of coal dust exposure involve changes in structure and function of the alveolar epithelium and the underlying extracellular matrix. Recent studies show that coal dusts exert direct effects to modify pulmonary epithelial cell-extracellular matrix interactions in vitro.3EXPERIMENTAL PROCEDURESType II cells isolated on day 0 by density centrifugation and differential attachment4 were plated overnight in D MEM containing 10% fetal calf serum before exposure to anthracite dust PSOC 867 sonicated into culture medium (750 ug/mL).3 Synthesis of extracellular matrix proteins was determined on day 3 of primary culture, as detailed elsewhere. 5 Cells were removed from extracellular matrix by extraction with NH4OH and high salt. Extracellular matrix synthesis and fibronectin content were evaluated based on radiolabeling with 3 H-leucine and on Western blot analysis, respectively. Additional analytical methods and calculations are detailed elsewhere.3-5"

Jan 1, 1998

By H. J. Heinen

The Bureau of Milts studied repetitive batch electrowinning of molybdenum from molybdic oxide ) to determine the effects upon the electrolyte life, purity of metal product , and overall cell performance. The electrolyte consisted of 54.0 weight-percent sodium tetraborate (Na2B407), 23.6 weight-percent sodium chloride (NaC1), 14.9 weight-percent sodium fluoride (NaF), and 7.5 weight-percent Mo03. The feed materials were pure and technical-grade Mo03. Electrolysis was conducted at l,000° C in a graphite cell in an atmosphere of air and carbon oxides. Electrolyte degradation did not occur during repetitive winning of molybdenum from pure Mo03 in an 8-day (5,400-ampere-hour) period of operation. Electrowon metal contained <0.1 percent total impurities. The electrode configuration is a key factor in the direct conversion of technical-grade Mo03 to metal by repetitive cyclic electrolysis. The best configuration found was a cathodic crucible and a central anode. Metal purity of 99.8 percent and a current efficiency of 91 percent were maintained until the combined impurity buildup the electrolyte reached 4.7 percent silicon, l.0 percent aluminum, and 0.6 percent iron. One pound of molybdenum was produced per 1.5 pounds of solvent salts employed. About 25 percent of the initial NaCl and NaF contents of the electrolyte were lost owing to volatilization and crucible penetration.

Jan 1, 1966

By D. R. Babich, E. R. Bauer

The U.S. National Institute for Occupational Safety and Health (NIOSH) is conducting a cross-sectional survey of equipment sound levels and worker noise exposures in the stone/aggregate mining industry. Six stone/aggregate mines (three surface and three underground) were recently surveyed, and the findings (ire presented here. The surveys consisted of sound-level measurements conducted around various equipment and machinery (including stone processing and crushing equipment) and full-shift dose measurements to determine worker noise exposures. The findings identify the equipment and machinery that are likely to cause worker overexposures and identify the workers found to he experiencing overexposures. In addition, the benefit of cabs in reducing mobile equipment operator noise exposure is discussed.

By N. S. Dalal, B. Jafari, F. H. Y. Green, M. M. Suryan, V. Vallyathan

"Freshly ground and aged anthracite and bituminous coal samples were investigated by electron spin resonance (ESR) spectroscopy to detect the presence, concentration and reactivity of free radicals. Freshly ground anthracite coal produced greater concentration of free radicals than the bituminous coal, and the radical reactivity was also greater for the anthracite. The reactivity of the newly produced free radicals in the anthracite dust correlated with the dust's toxicity. Furthermore similar coal-based free radicals were detected in the lung tissue of autopsied coal miners, suggestive of persistent reactivity by the embedded coal dust leading to the progressive disease process. Results of the studies on the severity of coal workers' pneumoconiosis (CWP) and free radical concentration m lung tissue support this hypothesis.INTRODUCTIONCOAL WORKERS' PNEUMOCONIOSIS (CWP) has been an important topic of concern to miners, mining engineers, epidemiologists and medical researchers for decades. It is well known that the prevalence and severity of CWP differ markedly between different regions and mines despite comparable exposures to respirable dust (REISNER and RoBOCK, 1977; HURLEY et al., 1979). These variations in pathogenicity of coal mine dusts can only partially be explained by differences in the mineral composition and by rank of coal (CHRISTIAN and NELSON, 1978; CHRISTIAN et al., 1979; HATCH et al., 1980). Cytotoxity studies on mammalian cells do not correspond well with the human disease pattern (CHRISTIAN and NELSON, 1978; CHRISTIAN et al., 1979; HATCH et al.,1980; VALL YA THAN et al., 1988). For example, while epidemiological studies of coal miners (REISNER and ROBECK, 1977; HURLEY et al., 1979) indicate that the prevalence of CWP correlates roughly with the rank of coal, such correlation has not yet been established in biological studies, despite considerable effort (CHRISTIAN and NELSON, 1978; CHRISTIAN et al., 1979; HATCH et al., 1980). In order to help resolve this apparent paradox we have undertaken a systematic study to evaluate whether any correlation exists between the concentration of free radicals present in fresh or aged coal dusts from two well-characterized U.S. coals. This study was also prompted in part by observations reported in the literature that organic free radicals can be formed on the surface of freshly fractured coals (LEBEDEV et al., 1978; DULIBA and CLARKSON, 1984). In particular, ARTEMOV and REZNIK (1980) noted that the decay lifetimes and, hence, the reactivity of the organic free radicals formed on crushing Russian coals, .depended"

Jan 1, 1989