Search Documents

By Michael J. Friedel

As part of an investigation aimed at improving the health and safety and competitiveness of the mining industry, the U.S. Bureau of Mines evaluated the application of common offset radar profiling, using a 250-MHz ground-penetrating radar (GPR) system, for the detection of fractures in igneous rock. A series of radar reflection surveys were conducted to detect and delineate the extent of fracturing at various granodiorite and gabbro quarries and outcrops located in Minnesota. The application of radar profiling for detecting joints, sheeting fractures, shear zones, and depth to water table was demonstrated to be feasible with minimal processing. Radar reflection interpretations were verified by visual inspection of the rock mass and field mapping of local structure. The radar reflection section provides a simple, rapid, and cost-effective means for mapping of shallow (less than 10 m) small-scale fractures (greater than 0.25 cm) in igneous rock masses (characteristic of velocities between 0.061 m/ns for gabbro and 0.125 m/ns for granodiorite). Depth or distance estimates to fractures are within 10 pct of the actual, and time-shift compensation is necessary only when topographic irregularities exceed 30 cm.

Jan 1, 2010

By W. M. Myers

Water has been commonly used as a collecting medium in many instruments employed in the sampling of dusty atmospheres in mines** add industrial plants, and for this purpose has much to recommend it, particularly the following factors:1.,Water is a very efficient dust collector.2.,Distilled water of great purity may be readily obtained at slight expense. The analytical error introduced by the extremely small amount of foreign matter in carefully distilled water is very small,3.,Water is a very convenient medium with which to work as all the analytical operations of diluting, aliquoting, and filtering are readily and speedily carried out. Water has therefore been used extensively in such instruments as the Palmer apparatus, the Greenburg-Smith impinger, and the dust collector recently described by Drinker, Thompson, and Fitchet. The Bureau of Mines has conducted investigations in many metal-mining districts of the country, determining of dust the nature and amount of dust present in working places, its effect the health of workers, and what precautions may be taken to decrease the hazard of exposure to dangerous dusts. The Bureau is therefore interested in any factor that affects the accuracy of dust sampling.

Nov 1, 1923

By Robert J. Tuchman

This report presents the origins of the Bureau of Mines and the evolution of the Pittsburgh Research Center from its inception to its present form. Areas of major research emphasis over the years, as well as administrative reorganizations, are discussed.

Jan 1, 1998

By R. L. Grant

The Bureau of Mines applied automatic computational methods to analyze the degree of correlation between sound transmission and atmospheric conditions. Statistical analysis of data collected over a 5-month period indicated that the following weather variables, listed in order of decreasing importance) have a significant effect on the transmission of sound in the atmosphere: 1. Wind velocity and wind direction. Winds in the direction of travel of the sound wave increase the sound intensity and duration. 2. Barometric pressure. High pressures are related to low sound intensities and durations. 3. Atmospheric temperature. High temperatures are related to low sound intensities and durations. Inversion of the atmospheric temperature did not appear to affect sound transmission under the conditions of this study.

Jan 1, 1967

"There mines are located in out of the way places, where timber is scarce and its price high, the problem of protecting it from fire risk is of considerable practical importance. Scarcity of timber for mining purposes is commonly met with in the more arid parts of the country, where, so, mine timbers are most likely to become dry, and inflammable, and where, therefore, the risk from fire is accentuated. Any effective and cheap method of securing adequate protection of such timber at the lowest possible cost is worthy of careful investigation. The use of magnesite cement has been suggested in this connection.The necessary qualities for any substance for the use suggested above may be summarized as follows: It should be resistant to abrasion, and to impact and structural stresses. It should be durable when subjected to the action of the elements, and stable to any minor derangements of the base on which it is placed. It must be relatively unaffected by changes in temperature, by the action of water, and should adhere to the material on which it is placed, and it should also be free from shrinkage cracks due to setting up the material, Magnesite cement appears to fulfill the various conditions outlined above.The elasticity of such cement is the outstanding quality which makes it desirable for exterior work. It also possesses the ability to adhere to all materials in a marked degree. Its freedom from expansion and contraction after setting is one of the principal reasons for its adhesive quality. It may be applied to old brick or stone walls, even tho they have been repeatedly covered with paint, and the quality of adhearing to wood makes it possible to secure a weather-proof protection to the wooden casings and trim of exterior openings. The quality of adhesion and elasticity is easily proved by applying a 1/2"" layer to a 1"" board which has been first covered with metal lath. Such a board, about 8 feet long, may be repeatedly deflected about 3"" in the center without breaking the bond to the board, or causing any cracks to appear in the magnesia cement. The ability to resist fire as well as the possession of insulating qualities are also desirable characteristics of magnesia cement stucco.Magnesite cement stucco should be applied in two coats, each 1/4"" thick on various surfaces such as wood lath, metal lath, sheathing board, brick, hollow tile, or stone; care being taken as regards the presence of lime, unless the same has been rendered, or become inert as with very old, walls. The first coat made up to a consistency that works easily under the trowel is applied in the usual manner. No water should be added to the liquid chloride as it would alter its density, and injure the work. The second or finishing coat is then applied. The aggregates are different in each, and no other dry material should be added to them as they come to the trade. The cement may be applied in zero weather without damage. Setting is quite slow under such conditions, but the cement ultimately becomes hard. It should always be applied to a dry surface excepting that under certain conditions it is desirable to apply a solution of magnesium chloride before using the stucco."

Dec 1, 1919

By Oliver Bowles

"Properties and Uses.Iceland spar is a name given to a pure crystallized form of calcite (CaCo3) which is sufficiently transparent and free of defects to be used in the manufacture of optical instruments. While the actual requirements are small, the degree of purity and physical perfection demanded renders it somewhat difficult to obtain suitable material.The properties of value in Iceland spar are its transparency combined with double refraction. It is used in the manufacture of polarizing microscopes, saccharimeters, colorimeters and photometers. Its most important use is in the manufacture of Nicol prisms, which constitute an essential part of every polarizing microscope. The principle governing the construction of the Nicol prism is as follows:Ordinary light in passing through a crystal of calcite is resolved into two rays of plane polarized light vibrating in planes at right angles to each other and having different indices of refraction. Thus the two rays follow different paths through the crystal. The prism of Iceland spar is cut diagonally and cemented together again with a transparent cement having an index of refraction intermediate between the two rays passing through the prism. Canada balsam is employed for this purpose. The prism is cut at such an angle that the ray having the greatest index of refraction meets the surface of the balsam at an angle greater than the angle of total reflection, and it is thus deflected to the side of the prism, while the second ray passes through. Thus one of the rays is eliminated and polarized light vibrating in a single plane is obtained."

Apr 1, 1920

By N. S. Dalal, X. Shi

While it is known that vanadate and related compounds of pentavalent vanadium ( V (V)) exert potent toxic effects on a wide variety of biological systems, the underlying biochemical mechanism is still not fully understood ( 1- 3). One of the pathways is thought to involve the oxidation of NAD ( P) H. Thus, considerable effort has been devoted to finding the mechanism of NAD ( P) H oxidation by Vcvi (1-15). Erdmann et al. (5) first noted that vanadate stimulated the oxidation of NADH by plasma membranes and attributed this effect to a membrane containing NAD(P)H-dependent V(V) reductase. Later studies by Liochev and Fridovich indicated that endogenous superoxide ( 02 ) plays a central role in this reaction ( 4, 12, 13) . They proposed that NAD ( P) H dehydrogenases or oxidases produce 02, which causes VCV ) to stimulate NAD ( P) H oxidation via the following free radical chain mechanism ( 4, 12, 13) :

Mar 1, 1992

By A. L. Murray, C. A. Allen

"In the Spring of 1919, the Industrial Commission of Utah undertook the assembling of safety orders covering metal mining operations Just at that time there appeared several articles in the mining papers advocating the licensing of hoisting engineers, so this subject was given careful consideration,The licensing of hoisting engineers means that they must pass an examination covering the mechanical features of hoists and boilers, and must have a certain amount of experience. This undoubtedly serves to get a class of hoisting engineers that are better informed about the mechanical operation and theoretical considerations in hoisting and the only room for argument against it is that it is difficult to give an examination that will determine whether or not a man is a competent hoisting engineer.A man might pass an excellent examination yet be absolutely unqualified to operate a hoist and the judgment of the mine super- intelligent would have to be depended upon to choose the right man from among those who were licensed. This difficulty of properly determining, by ordinary examination, a man's qualifications to run a hoist caused the idea of licensing' in the ordinary sense of the word to be abandoned; but, as there was no question that a hoisting engineer should be physically fit, it was decided to require a medical examination, and at the same time to require the hoist engineer to state his experience, so the State would better knowledge of his general qualifications.The orders covering the question were therefore issued as follows;"

Jan 1, 1920

By Alex U. Miller

Since its beginning, the occupation of coal mining has been considered hazardous. It is true that there are hazards inherent in mining, but it is believed that most of them, at least, can be guarded against. Moreover, many man-made hazards can be eliminated by officials and workers adopting safer practices. Notwithstanding the hazards in coal mining, the fatal accident rate in the United States has improved. During the, period from 1911, to 1941, inclusive, the fatal accident rate varied from 5.35 to 2.22 per million tons of coal. With many handicaps during the war period, 1942-45, such as the lack of experienced manpower. and the, employment of untrained men, the increased average age of workers, and the shortage of equipment and supplies, the industry s ill further reduced its accident rate, so that it ranged from 2.30 to 1.724/ deaths per millon tons of coal. During 1944, 684,000,000 tons of coal was produced with a rate of 1.91, and during 1945, 631,000,000 tons was produced with a rate of 1.724/ deaths per millon tons of coal. The accident rate for 1945 was the lowest for the industry since records have been compiled.

Jan 1, 1946

By R. V. Higgins

Many contributions to methods of forecasting the performance of waterfloods of a five-spot pattern have been made by investigators. In most of these forecasting methods, a previously selected sweep efficiency is used, and other simplifying assumptions are employed to obtain the objective. In this paper the calculated oil recoveries from several five-spot single- and multiple-layer stratified reservoirs were made with a minimum of assumptions, and because of the techniques used, no previously selected sweep efficiency was required. As a result, the accuracy of the forecast is increased. Permeability curves and continuously changing saturation gradients are used in every section of the pattern. By means of a potentiometric model, the flood pattern is divided into channels, the centers of which are the streamlines. The channels are divided into cells. As flood water enters, the permeability and saturation of each cell change with time. In this study the production from multiple-sand layers of different absolute permeability but with the same relative permeability-saturation relations are combined. The results are shown for a single- and 10-layer reservoir with a permeability variation of 0.60. The oil rate, water-oil ratio, and recovery are shown as functions of time for a 2- and 20-centipoise oil starting in primary phase and after fill-up.

Jan 1, 1962

Provide a rapid, reliable means of warning underground miners of a fire or other emergency. Approach An ultalow-frequency electromagnetic signaling system was designed, breadboarded, and tested at various under around mines. How It Works Current fire warning systems for underground mines, such as stench, audible alarms, and messengers, arc slow, unreliable, and seldom achieve total mine coverage. An ultralow-frequency electromagnetic fire warning alarm system with true through-the-earth signaling capabilities was developed to solve these problems. The system was originally designed for high-back room-and-pillar mines where stench systems are unusable due to the low velocity of mine air flow. However, the system has an application to all underground mines.

Jan 1, 1988

By L. J. Kane

Several processes being developed by the Federal Bureau of Mines to provide new and more efficient uses for coal require practical methods for removing dust from hot gases. Filters provide such means. The efficiency of filters made of aluminum silicate fibers and porous stainless steel was determined. The results obtained with the fibers were previously reported.5 In this investigation tests were made with three porosities of stainless steel filter material (grades C, D, and E) at a gas flow of 1,000 std. c.f.h./sq. ft. of filter, temperatures of 75° and 1,000° F., and dust loadings (as represented by cumulative dust fed) of 100, 1,000, and 10,000 gr./sq. ft. of filter. Pressure drop during the runs ranged from 0.1 to 21 in. of mercury, and dust removal from 25 to 99.93 pct. Filters having the finest pores gave the greatest pressure drop and percentage of dust removal; however, their dust-holding capacity was slightly lower. Usually, their ability to remove a higher percentage of dust at the same pressure drop more than compensated for the slightly lower dust-holding capacity. With increase in temperature, for the same weight rate of flow of gas, the pressure drop increased and the percentage of dust removal decreased. The effect of temperature was probably due to the accompanying change in the linear velocity and viscosity of the gas.

Jan 1, 1961

By Murray Jacobson

The Federal Coal Mine Health and Safety Act of 1969 established mandatory dust sampling of coal mines according to procedures prescribed in the Mandatory Health Standards, title 30, Code of Federal Regulations, part 70, published in the Federal Register on April 3, 1970. A laboratory was established in the Pittsburgh Field Health Group of the Bureau of Mines to process the coal mine dust samples collected by the mine operators. This paper describes the laboratory and presents the equipment and procedures used in processing these samples.

Jan 1, 1971

By K. C. Dean

A semiquantitative test for the presence and identification of cesium and rubidium in rocks, clays, and mineral waters has been developed by the Bureau of Mines. The test can be used in the field, as a guide for the prospector, geologist, or mining engineer engaged in location or development [w]ork. It comprises two simple spot tests of a solution prepared from the [m]ineral sample. Phosphomolybdic acid, added to a drop of the test solution, [d]etects cesium, rubidium, and potassium in quantities as low as 60 parts per [m]illion. Silicomolybdic acid, added to a second drop of test solution, enables the operator to distinguish between cesium and/or rubidium and potassium. Test procedures, equipment requirements, and limitations of the method are described in this report. Cesium and rubidium were discovered in 1860 and 1861 by Bunsen and Kirchhoff with a spectroscope. The elements usually occur together, particularly in granite and granitic pegmatites. Rubidium does not occur as an essential constituent of any known mineral, yet it is found as a minor element in so many minerals that rubidium is 16th in abundance in the earth's crust. Cesium, which ranks as the 37th most abundant element, is the principal component of pollucite and a minor element in a wide variety of minerals.

Jan 1, 1960

By D. G. Kesterke

The electrolytic reduction of uranium dioxide to molten uranium in fluoride baths at approximately 1,200° C was demonstrated. Electrolyte constituents were BaF2, UF4, and either MgF2 or LiF. Preliminary laboratory-scale experiments were made in which the uranium oxide was added continuously for 3 to 5 hours to the cell during electrolysis. Over 1,000 grams of metal of 99-8 percent purity was made in some tests, Major impurities were aluminum, barium, iron, silicon, carbon, and oxygen. The effects of cell design, geometry, and bath composition were investigated. Electrode arrangement was the most important factor in cell performance.

Jan 1, 1963

By Bruce D. Sartwell

A program was written which utilizes a remote teletype input to a time- sharing computer to plot charged particle or X-ray energy spectra which are stored in the memory of multichannel analyzers. The program, written in FORTRAN V, accepts the data printed out by the pulse height analyzer on paper tape and then, after reading these data tapes into the computer, plots on the teletype the desired energy spectra on a scale automatically adjusted for the maximum number occurring in the data. The program is flexible enough so that the researcher can subsequently expand or contract the vertical (intensity) or horizontal (energy) scales. With a slight modification, the program will accept data printouts from scalers or analog to digital converters. The program also includes a feature for integrating the energy peaks obtained by pulse height analysis.

Jan 1, 1970

By E. H. Denny

The coal and metal mines of the United States furnish this country with a large part of the fuel and material necessary to support our industries and thus make possible the welfare and prosperity of our people and even the continuance of our present-day scale of civilization. Mining companies furnish material to industry with one general purpose in mind -- the making of a profit on their work. Efforts are being made successfully and continually to reduce operating costs, to increase production per man, and to perform work as far as possible mechanically and with more efficiency. These efforts are made primarily to reduce costs, to increase production, or to do both - in other words to make more profits or more certain profits. In the endeavor to reduce expense companies are considering more and more the factors which enter into costs of production, among them the factor of accidents and their cost. This paper endeavors to estimate the approximate cost of accidents to the mining industry in order to present the saving possible through accident reduction or elimination.

Jan 1, 1929

By J. M. Riley

A fluorometric method using morin in an alkaline-buffered chelating solution has been developed by the Bureau of Mines for determining beryllium in ores and mill products. Apparatus for measuring fluorescence intensities of the beryllium-morin reaction is described. Preparation of the sample for analysis consists essentially of digestion with sulfuric, nitric, and hydrofluoric acids, fusion of the residue with sodium carbonate and sodium borate, Solution of the melt with sulfuric acid, and proper dilution. Chemical separation of other ions is usually unnecessary. The method rave reliable beryllium determinations on samples in the 0.01- to 0.37-percent BeO range. The method is particularly applicable to low-grade beryllium ores; however, semiquantitative beryllium determinations have been made on beryl containing 12.0 percent BeO.

Jan 1, 1956

Efficiently clear ice and frozen materials from ore-handling equipment. Approach Compressed air-propane torches that develop a high energy flame jet were used instead of ordinary propane torches. How it Works A high velocity high temperature stream of gases impinges on the ice and frozen materials to both melt and blast them away. This hot gas jet is at 3,000°F temperature and moving at 3,000 feet per second. In the photograph below, the jet is being used to clear frozen taconite from a grizzly. The functions of the compressed air-propane torch are as follows. The air heater assembly, which is mounted on a wand, con-

Jan 1, 1980

By C. J. Cohen, L. A. Dahners

"SUMMARYA method has been developed for surveying, drill holes without lowering into the hole any surveying equipment other than an etch tube. The orientation of the rods at the collar of the hole is maintained as the etch tube is lowered. The attitude of the etch ellipse in depth with respect to the rod orientation at the collar can then be observed. This relationship permits the bearing of the hole in depth to he calculated. The rod orientation is maintained during the lowering by means of a pair of alinement clamps. One clamp is fastened to the top of each rod as the rod is coupled and is removed when the alinement has been transferred to the other clamp at the top of the next succeeding rod. A particular advantage of this survey technique is that surveys can be readily made in magnetic country rock.PRINCIPLE OF THE TECHNIQUEAn axial lamina of the column of drill roes is the lamina in which one fiber would be the centerline of the rods. In the new survey technique, the rods are fed into the hole in such a manner that the axial lamina of each successive rod maintains its position at the collar of the hole. In depth, as the rods bend in following the drill hole, the axial laminae also bend. The lamina that was originally vertical will, in general, be tilted away from the vertical. The trace of this lamina is marked on the glass etch tube before the tube is lowered in the hole. The axial lamina that becomes vertical at the survey station is recognized as that axial lamina which contains the long axis of the etch ellipse. The angle between the lamina originally vertical and the lamina vertical at the survey station is thus measurable. When the vertical axial lamina at one survey station has been determined by the etch ellipse at that station, angle R between this lamina and the vertical axial lamina at the next survey station becomes measurable also. By moans of angle R, and dip angles D1 and D2 at the two stations, the change in bearing (z) of the drill hole between the two stations can be calculated."

Aug 1, 1944