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By R. L. Schmidt

Research conducted over the past 20 years in France, Great Britain, and the United States on the use of the large-hole burn cut has established cer¬tain advantages for this system. Advantages include longer pull and more complete fragmentation from blast rounds. However, research is needed to establish a set of parameters for optimum performance. As part of the Bureau of Mines Advancing Mining Technology for Marginal Resources program, the Twin Cities Mining Research Center, Twin Cities, Minn., acquired a horizontal rotary drill capable of boring holes up to 24 in. in diameter. This was used for a series of underground experiments at White Pine mine, White Pine, Mich., during 1973. Exceptional results were obtained with a 12-1/4-in void hole that yielded up to 18 ft of pull in a 10- by 20-ft drift, Fragmentation was excellent, and the compactness of the muck pile facilitated loading.

Jan 1, 1975

By Howard F. Puariea

This paper is one of a series describing methods and costs of recovering sand and gravel from alluvial deposits in the United States and deals directly with the methods employed by the Portland Gravel Co. in operating a clamshell dredge on the Willamette River near Portland, Oreg., and a pump dredge on the Columbia River near Vancouver, Wash. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent local expenditures only and not total production costs. It is recognized that publication of total costs may in some instances cause embarrassment to individual producers as well as to the industry as a whole. On the other hand operating costs are essential to the technical discussion and study of methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulations shall ensue.

Jan 1, 1932

By A. F. Jolly

In an effort to better predict the useful service life of friction rock stabilizer mine roof bolts in coal mine environments, the Bureau of Mines has evaluated the corrosion resistance of stabilizer steels in air-saturated and deaerated waters from seven Eastern and Midwestern underground coal mines. Accelerated electrochemical corrosion tests were used to estimate corrosion rates for the two high-strength, low-alloy (HSLA) steels used to fabricate Split Set stabilizers and for galvanized steel. Long-term static-immersion weight-loss tests were also conducted with the HSLA steels. Corrosion rates developed from the weight-loss tests (steady-state air dissolution) were roughly comparable to rates determined from electro-chemical testing in aerated waters. Although the highest rates occurred in waters with the highest chloride contents, rates in the other waters were low (<2.0 mpy) and exhibited little correlation to the widely varied chloride contents of the waters. The generally low corrosion rates are attributed in part to the tendency to deposit a protective CaC03 film, reflecting susceptibility to carbonate precipitation as indicated by positive Langelier (saturation) index values for the waters. With one exception, corrosion rates for the galvanized steel were (2.0 mpy. Rates with aerated waters were higher than those with deaerated waters. Pitting tendencies of the steels were also estimated.

Jan 1, 1987

By Philip W. Holland

The U.S. Bureau of Mines has developed an improved method for determining dissolved helium in water in the concentration range of 4.0 x 10-8 to 270 X 10-8 cm3 He (STP)/cm3 H2O. The method is a modification of a previously reported method that was developed for analrzing surface and subsurface waters in geochemical survey work. Water samples are collected in SOD-cm stainless steel cylinders, and the dissolved gases in a sample are extracted into an evacuated cylinder of equal volume. After addition of 30 psig of nitrogen containing less than 2 ppb helium to the extracted gases, the resulting mixture is analyzed for helium using a helium-tuned mass spectrometer. The helium content of the water sample is determined from an empirical calibration that is established by analyzing standard solutions of helium in water. The accuracy of the method is ±7 pct for helium-in-water concentrations above 10 x 10-8 cm3 He (STP)/cm3 H2O.

Jan 1, 1989

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 Raymond B. Ladoo

"Domestic Situation:The greatly increased use of lithopone as a base for paints, particularly for interior use, has timulated the demand for barytes to such a degree that the supply cannot keep pace with the demand. Lithopone is an artificially prepared compound composed of about 70 per cent barium sulphate and 30 per cent zinc sulphide, precipitated together. Its most important use is in paint, but it is also used in oilcloth, linoleum, rubber goods, shade cloth, etc.Prior to the war large quantities of barytes were imported from Germany, but during the war imports were negligible, domestic production increased very greatly and is still increasing. Ground barytes as used in paints/ formerly regarded as an adulterant, but now it is generally recognized as a valuable paint constituent. Mile domestic sources have expanded rapidly they have not overtaken the demand and there is need for still greater expansion. Stocks are low, little is being sold on the open market, and prices are high. Since barytes is a gangue mineral associated with metallic ores now being mined in the west, it is suggested that more attention be given to its recovery as a by-product.The following tables compiled from reports of the U.S. Geological Survey and the Bureau of Foreign and Domestic Commerce, indicate the growth of domestic consumption."

Jan 1, 1920

By A. Gene Collins

The Bureau of Mines conducted a research study of the geochemistry of the Smackover Formation to determine what geochemical relationships are useful in exploration for and production of oil and gas. Samples of oil, gas, brine, and rock were collected and analyzed. The oilfied brines were analyzed by methods recommended by the American Petroleum Institute and by tentative methods of the American Society for Testing and Materials. The crude oils were analyzed by Bureau of Mines methods; the gas, by Bureau of Mines methods; and the rocks, by wet-chemical, atomic absorption, and neutron activation methods. The results were correlated and interpreted, and several geochemical relationships useful in exploration and production were found. These include the type and class of brine, organic constituents in the brine, redox potential, in situ temperature and pressure of brine, degree of sulfate and carbonate saturation of brine, and halide concentrations in the brine.

Jan 1, 1974

By R. H. Sprute

Hydraulic backfill consisting of siliceous mill tailings was successfully dewatered and consolidated by electrokinetics in a field test conducted by the Bureau of Mines at the Star mine, Burke, Idaho. A stope at the 2,000-foot level was filled in such a way that slimes and coarse sand were retained in the scope. Following settlement of solids and decant of surface water, direct current applied between buried electrodes created a firm, dense material in approximately 3 hours. This rapid densification of fine-grained material demonstrated the utility of this method and suggests other applications, particularly in the control of slime deposits that cause serious problems in many deep mines.

Jan 1, 1975

By Deborah A. Kramer

As part of the Nation&apos;s growing concern with the competitiveness of U.S. firms in the world economy, especially with respect to advanced materials, the Bureau of Mines assessed the actual and potential recovery and manufacturing capabilities for gallium and gallium arsenide (Gacis). GaAs has advanced from a laboratory curiosity to a material with important "high-tech applications within only the last few years, and although protected North American gallium supplies are currently considered adequate, consumption could grow to the point that this assessment would need reevaluation.

Jan 1, 1988

By C. E. Saxon, F. E. Cash

"Adequate lighting for all mining operations would unquestionably tend to promote both safety and efficiency; this would be true not only for men but also for the animals that man impresses into service in mines. The Markeeta Coal Co. and the Alabama Fuel & Iron Co. both operating mines in Alabama, have found that equipping mine mules with portable electric lights is more efficient, much more humane, and far more safe for both men and animals then the more or less usual method of forcing the animal to do its work essentially in darkness.This report is intended to give the mining industry data, that will aid in trying to bring about safe and efficient operation of mines.The authors desire to thank Charles F. DeBardeleben, president, Fred R. Bell, general manager, Hewett Smith, C. H. Shepherd, and R. A. Sensing, superintendents for the Alabama Fuel & Iron Co.; and Charles F. DeBardeleben, Jr., president, and H. M. House, superintendent for the Markeeta Coal Co., for their cooperation in furnishing the data for this paper.The eight mines operated by the Alabama Fuel & Iron Co. and one operated by the Markeeta Coal Co. in Jefferson and St. Clair Counties, Ala., are the only mines in Alabama where mules are provided with portable electric lights, and there are few if any mines in other States in which this system is in use.These two companies are convinced that equipping all mine mules with good lights decreases underground haulage cost by animals by prolonging the useful life of the animals, increasing their efficiency, lessening haulage wrecks and delays on haulage, and increasing production. Last but not least of the advantages would be the more humane treatment of the animals.The nine mines are developed by slopes along the dip of the coal bed, with double-room entries on 200- to 300-foot centers turned right and left off the slopes and with approximately 1 per cent grade in favor of the loads. Rooms are driven up or diagonally up the pitch from these entries.A surface hoist delivers the empties from the surface to the entry sidetracks at the slope and pulls the loads to the surface. From these sidetracks, mules pull one to four wooden cars, each of which holds 1-1/2 to 2-1/2 tons of coal, deliver the empties to the rooms and entry faces, and pull the loads to the slope sidetracks. The mule haul varies from 100 to 3,000 feet; there are no locomotives or trolley wires in any of these nine mines, seven of which are rated as gassy and two as nongassy by the Alabama state Mining Department."

May 1, 1933

By G. W. Murrie, W. P. Diamond, S. W. Lambert

A geologic study of the Mary Lee Group of coalbeds in the Black Warrior coal basin was undertaken to examine coal stratigraphy and determine regional trends and extent of the coalbeds. The area investigated encompasses 835 square miles in Jefferson, Walker, and Tuscaloosa Counties, Ala. More than 700 core logs were used to construct a structure map, coal, interval, and overburden isopachs, and cross sections. There is evidence that structure affected sedimentation. Coalbed isopachs indicate the Mary Lee Group was deposited in fluvial-deltaic and low-lying coastal plain environments. The Mary Lee coalbed is the only coalbed which is continuous throughout the area, commonly with two benches which have a combined thickness of 2 to 12 feet. The Mary Lee coalbed changes rank in the basin from high- through medium- to low-volatile coal. The methane gas potential of the Mary Lee Group coals is estimated to be greater than 1 trillion cubic feet. There is an excellent correlation between the orientation of surface cleats with those measured underground in the Mary Lee coalbed. The face cleats roughly parallel the axes of the area&apos;s folds and trend northeast-southwest.

Jan 1, 1976

By Stephen D. Cramer

The Bureau of Mines conducted a series of in situ linear polarization measurements in high-temperature, high-pressure hypersaline geothermal brines at the Bureau of Mines Geothermal Test Facility in the Imperial Valley of California. The measurements represented an evaluation of the linear polarization technique for obtaining instantaneous corrosion rates of materials of construction in flowing hypersaline hydrothermal fluids that rapidly form scales on exposed surfaces. A special method was devised for use with the linear polarization technique that resulted in obtaining corrosion rates for 1020 carbon steel, 316 and 430 stainless steel, titanium, various nickel-based alloys, and aluminum 6061 under strong scale-forming conditions. The measurements also provided information on scale-deposition rates in various geothermal environments. Exploratory in situ potentiostatic polarization measurements were made in the flowing brines to qualitatively determine scale-deposition effects on the electrochemical measurements.

Jan 1, 1978

By August J. Kwitowski

This Bureau of Mines report describes how the reinforcement mechanisms of untensioned, full-column resin bolts were determined during one underground study. Both axial and transverse shear loadings were identified for two instrumented resin bolts that replaced standard resin bolts in an opera-ting room-and-pillar mining section. The strain responses of resin bolt steel cores to local axial and transverse shear loadings are described. This information was obtained from laboratory testing of resin bolts installations; it was also used to analyze the data from the underground test.

Jan 1, 1980

By McHenry Mosier

The diamond-drill method was tried at the site selected for driving a 5- by 6 -foot air shaft at the east end of the Bellefonte mine . This method of sinking consisted , first , of drilling a 5-3/4 -inch-diameter cut hole from the surface , then drilling parallel 1.5 - inch ( EX ) holes around it at appropriate distances for a balanced blasting round . The cut hole was not charged with explosive but served as a relief chamber for the incipient expansion of the ground broken by. blasting the surrounding 1.5 - inch holes . The length of each hole was 236 feet , which was the finished depth of the shaft . The nature of the work in the air shaft was largely experimental , and many difficulties arising from the lack of special equipment and proper technique for precise alinement of the drill holes caused expensive delays before they could be overcome . Drilling the 5-3 /4 - inch hole , which was impeded by frequent core blocks in the core barrel , required 10 shifts . average advance per shift for an EX hole was about 150 feet . The The holes were charged and fired from the surface . The length of the section blasted in one cycle was 10 feet . Blasting progressed from the bottom of the shaft upward . The broken stone dropped into a chute , from which it was drawn into cars on the haulage level . The Bellefonte mine is an underground limestone mine.3/ The primary objective in undertaking the research on shaft sinking by diamond drilling was to perfect a method for driving connections between levels of the mine .

Oct 1, 1948

By Charles W. Huggins

The Bureau of Mines investigated palygorskite, a natural asbestiform material, to accumulate knowledge that might serve as a foundation for future synthesis of a similar material. Unit cell, chemical analysis, DTA, TGA, optical constants, and electron microscopy data were obtained. Selected palygorskite samples of bettor than 97-percent purity were used to obtain this information. Chemical analysis revealed the following formula: (OH2)4 (OH)2 Ca0.01Fe0.02K0 .c3Mg2.10A12.00Si7.93020.3.91 H2O. The optical constants for sodium light are a = 1.522; S = 1.530; ?=1.533; biaxially (-). The following orthorhomibic unit cell constants were determined: ao = 12.690 A, Z = 2, bo = 17.857 A, Dx = 2.327. co = 5.207 A, Identical diffraction patterns resulted from the three palygorskite samples that were studied. X-ray, chemical, DTA, TGA, and optical data were compared with literature values for similar fibrous materials. X-ray diffraction lines were indexed. Several electron micrographs were made to compare the structures of palygorskite and attapulgite with that of chrysotile. The micrographs revealed extremely short laths for attapulgite, very long flexible laths for palygorskite, and tubular structure for chrysotile.

Jan 1, 1962

By W. P. Yant

The hazard to health from contamination of air by a noxious gas depends not only on the potential harmful response attending exposure, but also on the warning properties, which in effect may be termed the "accompanying warning response," This warning may be manifested as an odor, taste, irritation of the eyes, nose, or throat, or perhaps headache, vertigo, or nausea. These manifestations may be painful and even slightly harmful, but to a much lesser degree than the primary injury of exposure. The warning response mitigates hazards directly in proportion to the degree of Intolerability which accompanies injurious exposure, and accordingly its absence augments hazards. This accounts for the fact that the actual health hazards from a non-odorous or non-irritating gas or vapor of comparatively low toxicity sometimes equal or exceed the hazard from a considerably more toxic substance, but one which possesses a marked odor or produces eye, nose, or throat irritation in advance of harmful exposure. When a substance lacks the properties for giving warning, it is often possible to impart them by the addition of a small amount of another substance which has an exceedingly high warning intensity. The vapors of this substance, commonly termed a "warning agent" or "tracer gas," escape and mingle with the gas or vapor which lacks warning properties and thereby apprises persons of the latter&apos;s presence. The amount of the warning agent added is that which will give adequate warning in advance of serious physiological harm from the dangerous gas or vapor.

Jan 1, 1930

By Oliver Bowles

Granites are classed as igneous rocks ; they have been formed by the solidification of rock magmas or solutions from deep within the earth . It is an almost invariable law of nature that magmas which cool quickly form fine- grained or glassy rocks , while those that cool slowly are completely crystallized and are coarser- grained . Granites , being of the latter class , are regarded as having attained their solid form at considerable depth below the surface under conditions of high temperature and pressure . The constituent minerals crystallized out slowly , the crystals interlocking with one another . The great depth of overlying rocks that must have been present when crystallization took place has been removed by erosion over large areas on the surface of the earth , in consequence of which granites appear at or near the surface in many localities . The chief minerals of which granites are formed are feldspars , quartz , and either mica or hornblende . All the essential constituents except mica are as hard as , or harder than steel , therefore granites are difficult rocks to cut and dress . Granites are usually red , pink , or gray , depending on the color of the feldspars . If hornblende or black mica is abundant the rock may be dark green or almost black . Granites are characterized by massive homogeneous texture . They are classified as fine- grained , medium- grained , or coarse - grained . Medium- grained granites are those in which the feldspar crystals average about one- fourth inch in diameter . If relatively coarsegrained crystals appear in a fine -grained ground mass the rock is designated a porphyritic granite . Uniformity in texture and grain size are desirable in building and ornamental stone , although occasionally rocks of variable texture , such as the porphyritic granites , are used . A rock may have the mineral constituents of a granite but show a banded or platy structure due to recrystallization , folding , or other changes while the rock was in a plastic or semimolten condition . Such metamorphic rocks are called granite gneisses . They are used occasionally for building purposes but not as commonly as the uniformly textured granites . - Granites are named from the most abundant mineral other than quartz and feldspar that they contain , being called , for example , biotite granite or hornblende granite . - Commercially other igneous rocks granitoid in texture but more properly classified as syenites , diorites , or gabbros may be classed as granites . Thus the " black granite " of Little Falls , Minn . , is a diorite , and the " black granite " of Eastern Pennsylvania consists of diabase or gabbro . The question is sometimes raised as to the depth to which a granite occurrence may extend . In this respect granites differ notably from limestones , sandstones , or other sedimentary rocks . The sediments were originally laid down in relatively thin beds , and individual formations providing rock of economic value may be quite limited in thickness . Usually the usable beds range between 40 and 200 feet in thickness . On the other hand , granite comes up from below . Its depth is unknown , but in general is very great . It may even be measurable in miles . The reserves of material at depth are to be measured , therefore , by the economic depth of working rather than by the vertical extent of the rock mass . Exceptionally , granites of commercial quality may occur in sills or sheets of limited thickness flanked on either side by rocks of different character , as , for example , at Westerly , R. I.

May 1, 1930

By R. O. Kneisley

Rock mechanics measurements indicate that the present two-bed mine design used at the Big Island trona mine, Green River, Wyo., results in stable workings. Vertical pressure changes in the lower panel pillars and horizontal pressure changes in the lower bed roof and floor indicated negligible upper bed mining influence. Pillar stresses stabilized soon after upper bed mining was completed. Strata movements in the pillar ribs, roof, and floor were also negligible and stabilized soon after completion of upper bed mining. Using tributary area theory, the confined core approach, and studies of model trona pillars it is shown that increased extraction ratio is possible. A program of gradually increased extraction ratio accompanied by simple measurements should result in a mine design that includes both higher recovery and long-term stability.

Jan 1, 1981

By John Millhiser, Stephen J. Kravits

The U.S. Bureau of Mines preproduction Wireless Survey System (WSS) and its performance during an in-mine test are discussed in this report. The WSS was developed to reduce downhole surveying time in order to increase the efficiency of drilling long horizontal methane drainage boreholes in coal. Borehole survey data are electromagnetically transmitted from the WSS7s downhole guidance probe, via the drill rod, to the uph&apos;ole subsystem in less than 1 min per survey transmission, regardless of borehole depth. The WSS7s in-mine test consisted of providing borehole survey data during the directional drilling of a 2,538-ft horizontal methane drainage borehole in the Pittsburgh Coalbed. By considering available drilling time, which does not include hydraulic drill downtime and the time spent traveling portal to portal, 24 shifts were needed to complete the borehole. Of the available drilling time during the tcst, 50 pct of the time was spent drilling and 50 pct surveying and maintaining the WSS to keep it operational. Previous Bureau experience indicates drilling efficiency was increased 108 pct because of the WSS, in comparison with using a commercially available wire-run directional survey instrument at 10-ft intervals.

Jan 1, 1990

By H. C. Howarth

The preliminary tests referred to in this report wore made at the Bureau&apos;s Experimental Mine under the general supervision of G. S. Rice chief mining engineer, to determine whether rock dust way be used to extinguish or control mine fires. DESCRIPTION OF THE DUST USED The dust used for application by hand was made from draw slate taken from the Experimental Mine. This draw slate was crushed in a hammer-type crusher fitted with 1/16 inch by 2-inch slotted screens. A sizing test of the dust showed 96.5 per cent through 20 mesh, 69.4 per cent through 48 mesh, 46.2 per cent through 100 mesh, end 33.5 per cent through 200 mesh.

Jan 1, 1927