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Provide an inexpensive, remote actuated, stench-gas system which reduces fire warning time to underground work locations. Approach A mine's pager phone hard-wire network is used to release stench gas from pressurized canisters located near working areas. The release is initiated by placing a coded message into a control phone at some central location. How It Works Currently, in most mines, the decision to release a warning stench gas is made by mine management after communication from the mine of a fire or similar potentially dangerous situation. Stench gas is then released into the ventilation air and/or compressed air lines for dissemination throughout the mine. This can result in significant delays in warning time. Often, surface personnel must travel to distant shafts, or other release points, wasting valuable time. Also, the time for ventilation air to circulate from the surface to working locations can be long and the effectiveness of compressed air as a stench transport agent depends on whether the compressed air is being used at the face. The Bureau of Mines, through a contract with MSA Research Corporation, has designed and tested a warning system which avoids these problems. The system consists of multiple, pressurized stench-gas canisters located under-ground in the mine-ventilation network so as to provide quick dissemination of the released stench gas to working areas. Each stench-gas canister is hard-wire connected to a nearby pager phone and from there to a control phone at the surface or at a central in-mine site. In the event of a mine emergency, the canisters are activitated to release stench gas by placing a coded message into the control phone. A low amperage Signal sent from the control phone to the receiver phone closes a relay, which activates a release mechanism on the canister.

Jan 1, 1984

By F. J. Gallagher

The purpose of this circular is to present information on the construction and use of reinforced rubber-jacketed tubing and insulating air-line couplings in coal mines where Airdox is used for breaking coal in order to eliminate, insofar as possible, arcing at the face between Airdox tubing and the track or other face equipment.

Sep 1, 1949

By S. A. Matthes

This Bureau of Mines report describes a system for the dissolution of metal and mineral samples using a microwave heat source. Samples and an acid mixture are placed in sealed polycarbonate vessels. The vessel contents are heated using microwaves, digested for 2 min, and quickly cooled. After the solution is brought to a final volume, the vessel contents are heated an additional 2 min in the microwave oven. Using this method, a slag, a feldspar, and a Ni-Cu alloy were dissolved and analyzed by atomic absorption spectroscopy. Values obtained for Na, K, Cu, Ni, Si, Mg, Mn, Ca, Al, and Fe agreed with certified values and had an average relative standard deviation of 1 pct. This system results in a significant savings in time and expense over traditional methods of sample dissolution, and is ideal for preparing solutions for analysis by atomic absorption, plasma optical emission, or X-ray spectroscopy.

Jan 1, 1983

By Eugene V. Cilento, R. Clark Lantz, Kevin A. DiGregorio

"A microscope-based spectrophotometer has been developed to measure superoxide release from single pulmonary alveolar macrophages (PAM) or other phagocytes in culture. Results indicate that PAM respond to stimulation by phorbol myristate acetate (PMA). It appears that some PAM do not release 02 upon stimulation by PMA; however, those that do release 0, show differences in: (I) the total amount of 0, released, (2) the rate of release of 02 and (3) the time delay for release of 02. The significance of measuring 02 release from single cells is two-fold. It allows the simultaneous study of 02 release and electrical potential changes across the membrane of PAM and it allows the study of differences in 02 release among cells. Thus, the function of Normal PAM and the dysfunction of PAM exposed to coal dusts can be more closely studied on single cells.Pulmonary alveolar macrophages (PAM), free cells found in the lungs, protect the lungs by removing inhaled foreign debris and bacteria. The macrophages do this by engulfing and then internalizing the foreign matter (phagocytosis). Stimulation of PAM causes the release of super-oxide radical (02) which has been shown to be the primary metabolite involved in the killing of bacteria by phagocytes (3,8,12). The super-oxide radical is highly reactive and is spontaneously or enzymatically converted to other antibacterial oxidants, including hydrogen peroxide (H202), singlette oxygen ( 02), hydroxyl radical toil'), and hypochlorous acid (HOCl) (2, 3,8,11,12).Exposure of PAM to dusts may lead to dysfunction of this cell-type and to a greater risk of lung damage or infection upon subsequent exposure to toxic dusts. To date, much of the research with this cell-type has used cytotoxicity (cell death) as a measure of dysfunction. Although this is an important end point, PAM dysfunction may occur at doses below those which lead to cell death. In addition, dysfunction has been measured using large numbers of cells. In order to obtain a clear understanding of the mechanisms involved in dysfunction, measurements should be made on single cells. As mentioned earlier, one of the major roles of this cell type is its anti-bacterial actions. Therefore, asessment of release of superoxide radical in single cells is important in determining the functional behavior of PAM before and after exposure to dusts. Since measurements of 02 production have not been made on single cells the purpose of this study is to develop the methodology needed to study release of 02 from single cells.Recent studies have suggested that a relationship exists between the release of 02 and changes in the electrical properties of phagocytes. The change in membrane potential is thought to be the initial step in superoxide production (6,9). Stimulants which cause 02 release also cause changes in the transmembrane potential of phagocytes (9) and in the permeability of the cell membrane to ions (6). For example, stimulants which cause the release of 0, from neutrophils have also been shown to increase the membrane transport of Na+ , K+ and Ca+2 and stimulation of macrophages leads to increases in Na and perhaps Ca permeability with a subsequent change in membrane potential. In some cases, phagocytic activity has been shown to depend upon the extracellular concentrations of these ions (6). Holian and Daniele (7) have shown evidence that the redistribution ofcellular Ca in alveolar macrophages is an initial step leading to 0, release. In order to provide direct evidence that 02- production is related to electrical changes across the plasma membrane of phagocytes, these two phenomena must be analyzed simultaneously on single cells. Ultimately, measurements of 0, release using the methodology developed in this study will be combined with electrophysiological tech¬niques to study both superoxide release and membrane potential changes simultaneiously on single PAM, and to examine the effects of coal and mineral dusts on their physiological fu"

Jan 1, 1988

By Edmund S. Leaver, Jesse A. Woolf

"The Baboquivari mining district is about 60 miles southwest of Tucson, Ariz., the present railroad shipping point. The values are silver and gold. The silver is largely associated with the black oxides of manganese. The ore is highly oxidized, and careful panning shows only a very small amount of pyrite. Our sample analyzed as follows:A flotation mill has been installed in the district, but it does not concentrate the precious metals satisfactorily. Our best laboratory flotation results were obtained by grinding to pass 65-mesh and floating with Xanthate or standard flotation oils plus sodium sulphide and polysulphide. This sulphidizing method gave a concentration of 32 per cent of the silver and 80 per cent of the gold, which about equals plant practice.We do not know of an instance where the oxidized forms of manganese have been concentrated satisfactorily by flotation.Plain cyanide on the original ore extracts practically all of the gold but only one-third of the silver. A preliminary deoxidizing roast, using producer gas or powdered coal, gives a calcine from which cyanide dissolves about 90 per cent of the gold and 75 per cent of the silver. This method of treatment, known as the Clevenger-Caron process, is described in Bureau of Mines Bulletin 226.Preliminary treatment with sulphur dioxide by burning pyrite or sulphur and passing this gas into the pulp until all of the contained manganese is dissolved or changed in form best prepares the ore for cyanidation. The acid consumption will vary with the percentage of manganese and other soluble constituents. Neither gold or silver is dissolved by this acid treatment. The washed residue gives maximum cyanide dissolution of the gold and silver with minimum loss of cyanide,"

May 1, 1928

By Bruce I. Thomas

In 1943, the Bureau of Mines investigated the occurrence of cassiterite in the gravels of Morelock Creek which flows into the Yukon River 32 miles east of the confluence of the Yukon and Tanana Rivers in central Alaska. Samples of the gravels were obtained by churn drilling test pitting, shaft sinking, and open-cut mining. The gravels along Morelock Creek are about 6 feet in depth and covered with about 2-1/2 feet of overburden. The overburden is frozen, but the underlying gravels are not. Cassiterite, with gold and other heavy minerals, is usually concentrated in the first 2 feet of' gravel above bedrock and in some places penetrates into joint planes in the bedrock. The various methods of obtaining samples are discussed, and drill logs and analyses are tabulated in this report.

Jan 1, 1948

By L. E. Geyer

"The following list gives the title and author of various publications of the Ceramic Experiment Station, Columbus. Ohio, of the Bureau of mines, together with other ceramic publications of the bureau, which have been published in technical journals and by cooperating agencies. The list also includes the publications on ceramics which have been issued as bulletins, technical papers, or mimeograph Report of Investigations of the bureau.Papers Published in the Technical Press.The Effect of some Electrolytes on the Properties of Clays. Schurecht, H.G. Jour. Am. Cer. Soc., Vol. 1, #3, March, 1918.A Pycnometer Operated as a Volumeter. Schurecht, H.G. Jour. Am. Cer. Soc.,Vol. 1, #8, August, 1918.The Properties of some Ohio and Pennsylvania Stoneware Clays. Schurecht,H.G. Jour. Am. Cer. Soc., Vol. 1, #4, April, 1918.The Fusibility of Graphite Ash and its Influence on the Refractoriness of Bond Clay. Booze, M.C. Jour. Am. Cer. Soc., Vol. 2, #1. Jan., 1919.Behavior under Brass Foundry practice of Crucibles containing Ceylon, Canadian and Alabama Graphites. Stull, R.T. Jour. Am. Cer. Soc., Vol. 2, #3. March, 1919."

Oct 1, 1924

By A. D. Garman

This paper presents one of a series of digests of foreign mining legislation and court decisions which is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries . This interpretation of the laws of Nicaragua has been prepared from the best available information in Washington , but is released subject to correction and amplification , if necessary, by the proper American diplomatic and consular officers to whom it is being referred through the courtesy of the Department of State .

Jul 1, 1930

By H. Foster Bain

Ten years ago there was no general , country-wide service for the systematic training of miners in matters relating to safety . A beginning only had been made at a few scattered points . Under the old conditions each man was left largely to look out for himself in meeting the hazards of his day's work, and the foreman , shift bosses , and superintendents chiefly relied upon improvision when major accidents occurred . So long as the mines were small and the workers highly intelligent and well trained in routine mining methods , and when too , the pressure for output had not yet speeded up industry to the extent it has since those days , there was something to be said for this lais- sez faire attitude . When , however , the rapid expansion of industry lead to the introduction of new and little trained labor and to units of production of greatly increased size , the natural dangers of mining were greatly intensified . An accident in a small mine affects only a few; the same accident in a large mine , unless proper precautions have been taken , may cost the lives of many . The public does not generally recognize that the greatly increased outputs of the mines , of coal mines in particular , have been in recent years , obtained from substantially the same number of miners as ten years ago but with a personnel not nearly so well trained in mining . It is inevitable under : such conditions that more care must be devoted to avoiding accidents and much more elaborate preparations made for meeting them . In the years immediately preceding the establishment of the Bureau of Mines this speeding up of industry , change in the character of mine labor , and increasing hazard had all begun to be felt . Immediately prior to the organization of the Bureau of Mines , public attention had been drawn to a series of disastrous coal-mine explosions , to the increasing frequency of these disasters , and to the terrible loss of human life . resulting therefrom. One of the first problems , therefore ; confronting the Bureau was clearly that of finding methods of reducing the number of such disasters and lessening the severity of those that continued to occur . Toward this object were immediately directed the energies not only of the Bureau of Mines but also those of State mine inspectors , mine operators and various other agencies , all of whom were urged to cooperate in this great humanitarian work. The results of this work naturally cannot be measured by figures only . Work for increasing the health , safety , comfort , and happiness of human beings may not be gaged with mathematical precision . But certain features of this work as revealed by the record from year to year are of much interest . ”

Apr 1, 1921

The Bureau of Mines believes that all coal mines are potentially gassy; for the purpose of administration in the prevention of explosions and fires, the Bureau recommends: That any coal mine wherein methane or other combustible gas can be detected in amounts as much as 0.27 of 1 percent or more by frequent systematic searches shall be classified as a gassy mine. Permissible methane-indicating detectors such as are given in I.C. 7110 or subsequent lists of Bureau approved methane-indicating detectors, or conventional methods of sampling and analysis of required accuracy may be used. The concentration referred to in the decision is percent by volume.

Jan 1, 1941

By F. T. Eddingfield, F. E. Wormser

"The premium on gold in London, reflecting the further depreciation of the pound sterling, has risen from about 22 per cent as noted in these reports for December, to about 28%. This will enable more South African gold mines to come into the profitably ;reducing class, and will also tend to increase the gold production from that region.Figures are now at hand showing the drop that occured in the sold output in the Transvaal, South Africa, during 1919, in which year 8,330,091 ounces of gold were produced against 8,418, 292 ounces in 1918, a decrease of 88,200 ounces. Annual gold output from this, the most important gold area in the world, has dropped almost one million ounces in the past three years, as the following table shows:Although the decrease in not as marked comparatively as that of 1918 over 1917, it is a further indication of the general world-wide curtailment of gold production, and the steady decline in production everywhere that is going on and will continue until some rational means is found to stimulate production, or until conditions return to normal.The subject of relief for the gold miner has received attention in all parts of the world, particularly in the United States and South Africa in the past few years, but in spite of all the plane that have been formulated to remedy the situation none have yet been adopted anywhere, due mainly to great danger of tampering with the gold standard. In the United. States a plan has advanced by H. N. Lawrie of the American Mining Congress to tax the new gold entering into manufacture of jewelry or the arts in general, as furnishing some measure of increased compensation to unprofitable gold mining.Gold production in Australia, as indication by figures issued by the Australian Mines department, shows a marked decrease, and for the first ten months of 1919 amounted to 914,957 ounces against 1,073,317 ounces for a similar period in 1918. Western Australia produces about two thirds of all the gold rained on that continent. The total gold production of Australia for 1919 will reflect the universal decrease in output.Ever since June 7, when the embargo on the export of gold Was lifted, there has been steady and heavy outflow of gold from this country, as a consequence of which considerable gold accumulated during the war has been exported. Changes in the gold money stock of the United States are shown by the following table:"

Jan 1, 1920

By H. H. Schrenk

[A colorimetric method5/ for the determination of benzene in amounts as low as 0.001 mg has been developed recently at the U.S. Bureau of Mines Pittsburgh Experiment Station by the authors, with the assistance of chemical personnel fro a the Allegheny County (Pa.) Relief Works Division. The method is based on the direct nitration of either liquid - or gas - phase benzene, followed by neutralization, extraction with butanone, and final treatment with sodium hydroxide which produces a violet color. The color is matched with color standards of known values. Although the method is adaptable to many conditions the primary objective was a procedure that would be suitable for hygienic investigations. The development worth included a study of possible interference by chemicals that be present in those situations in which the method. would be employed. In this study it was found that a specimen of hexane prepared by the Gulf Research Laboratory, Pittsburgh, by fractionation of West Virginia natural gas gave positive result for benzene, whereas a specimen of pentane prepared in the same manner showed only a trace, and specimens of n -heptane and octane (2,2,4 trimethylpentane) supplied by Eastman Kodak Co. save a negative result. According to information obtained from the Eastman Kodak Co. the latter two compounds were highly purified, the n-heptene being prepared from line and the octane synthesized in the laboratory. On nitration of a larger amount of tae natural hexane a visible quantity, of needlelike crystals which resembled those of m-dinitrobenzene was obtained. The hexane from this nitration was recovered by distillation and again nitrated, but no crystals or colorimetric indication of benzene was obtained. This imitated that the specimen of natural hexane contained a substance which at least had the chemical behavior of benzene.]

Jan 1, 1935

By H. H. Schrenk

[A calorimetric method3/ for the determination of benzene in amounts as low as 0.001 m has been developed recently at the U.S. Bureau of Mines Pittsburgh Experiment Station by the authors, with the assistance of chemical personnel from the Allegheny County (Pa.) Relief Works Division. The method is based on the direct nitration of either liquid or gas - phase benzene, followed by neutralization, extraction with butanone, and final treatment with sodium hydroxide which produces a violet color. The color is matched with color standards of known values. Although the method is adaptable to many conditions the primary objective was a procedure that would be suitable for hygienic investigations.]

Jan 1, 1935

By L. C. IlsLey

Minin,g Qr col-cu.ttint till:I chines are 1?;\i9ng the _m9t wideiy .used de1sses ()f mining equipment.· These 1T:.i:1Chines ,.--re practicaily t-tl\·operc1_ted eiyher_by compressed .iir or by electric. ·motors. According to &.ta• compiled _ from the 122. issue COAL CATALOG\JE. OJMEINED WITH; OOAL "FIELD 'pf!:fC'TOTl1, bf 7,088. mnes from which reports were obttiined there -are 3895 mines that u.se coal-cutting eql;lipmen:ts,, 'f'hi report lists 20,031: r.ct:lchines, 17,&75 being operated by·elct:i.c.m<;>_tors··:r;id :the remtiinder by compressed i.r motors,· ,-. · ', .. . · .. ··, .. _ ,· .,, .. .. . . . . . : ; "'l t:: On tl.Ccou-nt .. of the wide· use of coc:11-cutting -.:i"cliine_- any Stat!;ls have issued regulationa as "to their operation dnd be to safety precautions that.should be observed J especially in gaseous mines.

Oct 1, 1922

By Roger J. Morrell

The Bureau of Mines conducted drag cutting experiments in hard, abrasive rock in an effort to extend the capabilities of an experimental kerf-core mining machine. The basic kerf-core mining machine cannot be used in hard, abrasive rocks because of the high wear experienced by the kerf cutters. These experiments were conducted in an effort to develop a method of preweakening the rock ahead of the kerf cutters in order to reduce the high cutting loads and hence the higher wear rates experienced by the cutters. The two "preweakening" techniques studied were indenting with mechanical wedges and single and double slotting with diamond saws. The best cutter force reduction achieved with mechanical indenting as 70 pct, whereas double slotting achieved force reductions of up to 99 pct. Conceptual designs of preweakening systems that could be retrofitted onto the basic kerfing cutterhead were developed for both the indenting and the slotting techniques. A high-energy impactor with wedge bit was used for the indenting method, and high-pressure water jets were used for the slotting method. A preliminary technical and economic analysis was performed for both of these full-scale systems to illustrate the methodology and to point out the important technical and economic factors that must be considered.

Jan 1, 1987

By A. L. Engel

As a part of the program of the Rare and. Precious Metals Experiment Station, Reno, Nev., in connection with investigations of treatment methods for precious and precious-base metal ores, to further conservation and recovery of precious and base metals, tests Were made on samples from the Buzzard Mine, located in the vicinity of Placerville, Calif. These samples represented ore exposed during previous development work, in tunnels and a shaft on the property, including highly oxidized material from the surface zone and sulfide ores from depths of 150 to 300 feet. The surface samples contained little base metal and only enough gold 80 that economic exploitation of them would depend on development of a large tonnage of ore, low-cost mining methods, and satisfactory treatment methods. The sulfide samples were valuable enough to warrant further exploration and development and, if present in suitable tonnage, the installation of a treatment plant for recovery of both precious and base metals. The oxidized surface-zone samples carried 0.11 to 0.14 ounce gold per ton. Standard amalgamation and flotation tests of these samples gave low recoveries. Standard cyanidation tests indicated high consumption of lime and cyanide and gold extraction of 79.4 and 82.7 percent. Water-leaching the ore after crushing to minus 10-mesh improved cyanidation considerably. Ex-tractions of 82.7 to 85.8 percent were obtainec1 with lime consumption of 6 to 7 pounds per ton of ore and cyanide consumptions of 1 to 4 pounds. Grinding the samples to minus 200-mesh followed by water-leaching and cyanidation gave improved extractions of 91-92 percent of the gold, but with slightly increased consumptions of lime and cyanide.

Jan 1, 1949

By Leonard J. Prosser, Joseph Cervik, John H. Perry

The Bureau of Mines has developed several techniques for draining methane from coalbeds in advance of mining. Drilling long horizontal holes from an underground location is one such technique, which was successfully demonstrated in the Pittsburgh and Sunnyside Coalbeds. The same technique has now been applied in the Mary Lee Coalbed at Jim Walter Resources, Inc. &apos;s No. 4 Mine, Brookwood, Ala. , where two holes were drilled horizontally--one to a depth of 1,010 feet (308 m) and the other to 540 feet (165 m). The 1,010-foot (3083) hole proved successful in degasifying a portion of the Mary Lee Coalbed. The hole drained methane for 1 year, during which time the initial gas flow of 200,000 ft3/d (5,663 m3/d) declined to 65,000 ft3/d (1,840 m3/d). Total gas production was 40 x lo6 ft3 (1.1 x lo6 m3 ). The gas was of commercial quality, with 98 pct methane and a heat rating of 990 Btu/ft (36.89 Mj/m3). The methane emissions from the faces of the mine section advancing into the degasified zone were reduced by 60 pct. The 540-foot (165-m) hole was terminated prematurely when it became impossible to maintain an open hole. Because of caving, very little gas was drained through this hole.

Jan 1, 1982

By John H. Perry

The Bureau of Mines has developed several techniques for draining methane from coalbeds in advance of mining. Drilling long horizontal holes from an underground location is one such technique, which was successfully demonstrated in the Pittsburgh and Sunnyside Coalbeds. The same technique has now been applied in the Mary Lee Coal bed at Jim Walter Resources, Inc.&apos;s No. 4 Mine, Brookwood, Ala., where two holes were drilled horizontally--one to a depth of 1,010 feet (308 m) and the other to 540 feet (165 m). The 1,010-foot (308-m) hole proved successful in degasifying a portion of the Mary Lee Coalbed. The hole drained methane for 1 year, during which time the initial gas flow of 200,000 ft3/d (5,663 m3/d) declined to 65,000 ft3/d (1,840 m3/d). Total gas production was 40 x 106 ft3 (1.1 x 106 m3). The gas was of commercial quality, with 98 pct methane and a heat rating of 990 Btu/ft3 (36.89 Mj/m3). The methane emissions from the faces of the mine section advancing into the degasified zone were reduced by 60 pet. The 540-foot (165-m) hole was terminated prematurely when it became impossible to maintain an open hole. Because of caving, very little gas was drained through this hole.

Jan 1, 1982

By D. B. Dow

In collecting and dissctinating inforr:.at'ion on ir.:,provec.. practices us0i in the pr eduction cf petroleur:1 and in the r;:;.:.1.nuf __ cture of gasoline, the Bureau of Mines ha.s aidei in creatin5 an interest i-n efficient 11:ethods in all phasas of tr.e oil ani gi:i.s iniustry. In the refinin£ ir...mstry ther.:: is a growing tend.ency for incre.:l.sea. effi. ,:;iency, ana inforr;.Eition rela:tin!s to ic:;p·roved practices should be of value not only to the larger and. core efficient plants, but particularly to srr.a.11 refineries unable to carry out a lar6e experLnental pro!§.rarn. The refi?eries of the United States required 4.3,915,029 barrels cf crude oil J.uring the year 1920*, inclu.::.in1:, 611136,210 barrels of Mexican cru::...e. This yielded. 4,8821546,599 gallons of E>asoline, a.n avara.t;,e ciaily pro;.iuct1on of 13,340,291 e,allons·, Besides the easoline obtainel fro;., cruie· oil by-fr:;.cticna.1 distillation and. from heavy oils by crackini:,, this a,-r;ount incluC1.es 3,152,924 bar­rels of natural-ga.$· gasoline blended. With asoline fro,., th otha two sourcs.

Apr 1, 1922

By David A. Monaghan, Kenneth R. Maser, Adi R. Gurdar, D. Randolph Berry

APPENDIX D DEVELOPMENT AND EXPERIMENTAL VERIFICATION OF ACOUSTIC SEAL CHECKER THEORY 1. Introduction In Section 7 of the report the acoustic seal checker concept was described in a general manner and the parameters which affect the signal level at the microphone were discussed briefly. In this appendix the theoretical basis will be presented and the experimental program described which permitted the extension of the theory into practice. The basic goal of the acoustic seal checker is to relate the reduction in sound pressure level to the size of the residual hole in the fly ash barrier. The smallest hole size that may be measured is determined by the signal to noise ratio, where the noise in this case includes the ambient noise in the mine, the internal microphone noise and the sound transmitted from the acoustic source via the flanking paths through corridors adjacent to the one being sealed. The latter source of noise can be discriminated against, at the expense of increased complexity of the acoustic system, by employing a pulsed source and pulse gating of the microphone signal set to accept sound via the barrier path and to reject the delayed flanking path signals. In order that the acoustic system be insensitive to precise source and microphone location and to permit assessment of system performance on an acoustic power flow basis, a broad frequency band of pseudo-random noise is emitted by the loudspeaker source. The preferred frequency range must be determined, the advantage of a directive source must be assessed, and the necessity

Jan 1, 1973