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By Richard H. Oitto

The Bureau of Mines and Kaiser Steel Corp. are cooperatively demonstrating the shield-type roof support in the longwall mining of a 10-1/2-foot-thick coalbed at the York Canyon mine near Raton, N. Mex. As part of the demonstration, the shield supports have been successfully and safely moved from a completed longwall face to a new longwall face. When these shield supports were moved in 1976 they were the largest and heaviest longwall support system in use in U.S. coal mines. The shield supports, preparations for moving them, the actual move, and installation at the new face are discussed.

Jan 1, 1977

By John Gross

In connection with some investigations being made at '!'he Ra.re uid Precious 1ets.ls Station of the U, S. Bu.rea.u of Mines, at Reno, Nev., on the precipitation of gol'i and silver from cyanide solutions, it wa.s sug­ gested tnat the use of acetylene for this purpose be investigated, A pa.tent was iss·.ied to Fre<!.erick W. Martin and Frederick Stl1.bbs in 1900 covering the precipitation of precious metals from cyanide solu­tions by acetylene, The acetylene used in the tests described below wa3 made f'rom a. corr.:nercial cal ci \'!Z:l carbid.e, A r..umber of exper:me11. +,s rezul ted in more or lP.ss ccmplete pree;p1tatien of silver, -but 1n no case was a11Y gold precipitated. As silver acetylide, obtained by precipitatir.g the silver from an ar:::ncni'i\.Ca.l so1ut1on of silver n,. tra.te by acetylene, is yellowish white, esn:, solu'.)le in cyanide and hlghly explosive, and the pr9cip1tate ob­tain£ frcvm the cy'31lide sclutions was black, not tlubla L., cyanide and not explooive, it 'Na.s deid-,d. to ir.·.restigate the na.tur.e of the slJ.ver pre­cipit.te !rem the cy;r:iide solu·t:i.i,ns, !n prepa;.•i::lg a lge (!\,wrttity ,:f the preci-pi tte 1 t. wa, fo·und that a.fter c,:.\i;:1 ete prEc"'.pi tat ion cf the eil ver the !IOl ution con ta.ined soluble eulphic.e • Thia p:!:'O'lided a el f!W "lt·d. a.ft er apr,ropri-9.te tests the preeipita.te VIO,I proved to 'be ailver sulphide.

Apr 1, 1922

By Oliver Bowles

The United States Bureau of Mines has within its ranks a group of engi- neers who are engaged in working out quarry problems, the solution of which will be of general benefit to the industries involved. The problems undertaken are approached in a systematic and thorough manner, all the evidence for and against any proposed change or new development being collected as carefully as an attor- ney would prepare his data on an important case. Unlike the attorney, however, the Bureau engineer does not take sides; his judgment is based entirely and in- partially on the array of facts presented. In order to gain the desired infor- mation he visits many plants, consults with the leaders in the industry, works out experiments in his laboratory, and supplements this information with a stu- dy of all available literature already published on the subject in any part of the world. As an engineer who has for eight years conducted such inquiries in the stone industry, I propose to discuss the Bureau of Mines viewpoint; and it may be of interest to consider with me in a brief and general way the engineer's method of looking at quarry problems, and some of the results attained through past and present labors. While the Bureau has conducted no investigation directly for the crushed- st one industries, two years of investigative work at cement-plant quarries, and work now being conducted at lire-plant quarries, has a very direct bearing on the problems of the crushed-stone industry, since stripping, drilling, blasting, loading, and transportation are similar in many respects in all stone quarries. The results of cement-plant quarry investigations are to be found in Bureau of Mines Bulletin #160. (b) Two short papers on lime-plant quarry problems have been issued in mimeographed form as Serial #01 (c) and Serial 3 (d).

Jan 1, 1923

By L. C. IlsLey

It is most unfortunate that a few must often suffer , and perhaps die , that many may benefit from a fuller appreciation of the dangers surrounding mining operations , and the proper use of safeguards designed to offset these dangers . This has been the case during the last few months in the anthracite field , where several explosions , resulting in burnings and fatalities , were undoubtedly caused by the use of defective or improperly assembled flame safety lamps . Had this same lack of understanding regarding the proper assembly of this safety device , and had the same indifference on the part of the user in keeping the lamps locked at all times and in proper condition , been permitted in a region where the coal dust was explosive , a terrible disaster would surely have resulted . In nearly every coal -mining country , including the United States , the Davy and Clanny type of lamp has been superseded , and rightly so , by some kind of bonneted lamp . Bonneted lamps , especially of the naphtha type , while much safer than the unbonneted , have more parts and need more care in assembling . For this reason the burden of responsibility for their being properly assembled rests with the lamp man ; therefore , it is extremely important that only competent , conscientious men be given this work .

Dec 1, 1921

"Health standards in the U.S. are among the highest in the world. Achieving these standards have often had an impact on productivity, slowing output, and raising prices to levels that make it difficult to compete with many foreign industries. The answer to many of these problems lies in the development of new and advanced control techniques. This overview has identified some of the major respirable dust technological hurdles that have been overcome, and provided some insight into current and future approaches underway to remove these obstacles and to provide the United States with the most advanced state-of-the-art mining industry in the world from a respirable dust standpoint. The necessary developmental research is costly and time-consuming. The long-term, high-risk aspects of this effort are being addressed by the Bureau and the Generic Center on Respirable Dust, with support by industry. This should be recognized as one of the principal agents through which the great mineral potential of this Nation can be realized, and our international status as a mining power be assured without compromising the health and welfare of those who ensure it.The problem of more stringent dust standards will continue to grow. To date, approximately 40 pct of the coal mining industry has been placed on more stringent dust standards due to quartz. Control techniques must be improved if mandated levels are to be met. As longwall production increases, dust levels will also increase. In light of the industry trend toward longwall mining, if no new control technology is available, the Federal dust standard will act as a constraint on future output per hour. The Bureau has recently completed a survey of 18 coal preparation plants; 50 pct of these operate at dust levels which exceed 2.0 mg/m3; future work will be directed toward solutions in this area. The 2.0 mg standard for respirable dust is for dust particles which are below 10 pm in diameter. Recent studies have shown that dust in the range between 10 and 25 pm can cause obstructive airway disease. The Bureau is currently determining the extent of exposure to dust in this size range from various mining operations."

Nov 1, 1988

By V. A. Marple, K. L. Rubow

"Filter samplers are one of the simplest methods and, in some instances, one of the only methods that can be use to obtain samples of particulate matter suspended in a gaseous medium. Once collected, particles are normally analyzed directly on the filter by gravimetric, chemical or microscopic techniques. However, it is sometimes desirable to resuspend the particles in an airstream for analysis. This would be the case if the size distribution of the particles were to be measured using one of many particle sizing techniques such as inertial classifiers, optical particle counters or the TSI Aerodynamic Particle Sizer CAPS).A ·technique has been recently developed whereby one can resuspend particles from filter samples in an airstream. The technique has been used for the resuspension of coal dust from filters. The resuspended particles were then introduced into the APS. This development was necessary since an APS can not be taken directly into an underground coal mine. For this application, particle samples are collected on membrane filters in the underground mines. The mass concentration of the particles determined through gravimetric analysis. The particle size distribution was tl1en determined by resuspending the particles and passing them through a TSI Aerodynamic Particle Sizer (APS). Excellent agreement has been obtained between the size distribution directly measured underground with a cascade impactor and that measured from the resuspended particles. For this experiment, an open-faced filter sampler was placed adjacent to the cascade impactor in the n1ine. The particles collected on the filter were resuspended in the laboratory and Measured with the APS.A venturi aspirator is used in the apparatus developed for resuspending the particles. The venturi has a small diameter capillary tube placed in the venturi throat. High velocity air flow is passed through the venturi, thereby, creating a low pressure region at the exit of the capillary tube. The low pressure draws air through the tube. The filter with deposited particles is located at the inlet to the capillary tube where the air flow into the capillary resuspend the particles. Once airborne, the particles are deagglomerated as they pass through the high velocity air flow in the venturi throat."

Jan 1, 1989

By Henry D. Hibbard

The object of this report is to give briefly information of present value relating to the manufacture and uses of the various commercial alloy steels, with the hope of stimulating the demand for such steels and extending their practical use. The report is issued by the Bureau of Mines as a contribution to the increase of efficiency in the preparation and utilization of the mineral resources of the United States. Alloy steels are included in the so-called special steels, but as the latter term is often used in the mills to designate broadly any steels intended for purposes other than those served by the regular product, it has seemed best to use the more specific term of alloy steels in this report. Alloy steels are bringing about a series of revolutions in various in- dustrial fields in which steel plays an important part. Most elements that could be procured in sufficient quantity have been alloyed with iron in various proportions, either alone or in combination with others, in the search for useful alloy steels. Those steels that have gained and maintained for themselves a place in current use are discussed in this report. Some of them have had an ephemeral life of usefulness which would no doubt have been prolonged had not some other more satisfactory steel been developed. Probably the first useful alloy steel was Mushet's self-hardening tungsten tool steel, patented in 1868. Fifteen years later chromium steel, really containing chromium, was struggling for recognition for some purposes, the chief of which was for the manufacture of solid shot for piercing armor. In both of these steels the effect of the alloying element as used was in a way proportional to the amount contained. In 1882 Hadfield made his epoch-making discovery of manganese steel and demonstrated that in iron metallurgy it is not safe to take for granted anything as to the properties of an alloy of iron with other elements, basing one's opinion on past experience and knowledge, and that the effect of an alloying element may not be proportional to its content. The development of useful nickel

Jan 1, 1915

By Henry Kreisinger, F. K. Ovrız

Some of the investigations conducted by the Bureau of Mines have for their object the collecting and disseminating of information regard- ing methods by which the fuels of the country may be most effi- ciently used. As the analysis of flue gases tends to develop better methods of firing, which in turn reduces waste of fuel, the Bureau of Mines in this bulletin presents for the benefit of those in charge of boiler plants and all other persons interested detailed information on methods of sampling and analyzing flue gases, and on the utilization of the analyses in promoting boiler-room economy. This bulletin is intended to be a companion to Technical Paper 80," and is written in plain and nontechnical language, as far as pos- sible, so that it may be readily understood by persons who have not had the advantage of a technical education. Whenever possible, illustrations of apparatus and methods of handling have been used rather than elaborate descriptions. The material presented in this report is arranged in two parts. The first part contains the description of the apparatus and the methods used in sampling and analyzing flue gases. The second part gives experimental results obtained with the different methods of sampling and collecting flue gas that are recommended in the first part of the report. Only simple apparatus and methods are considered, as they are accurate enough to show the large heat losses due to the use of too much air, and are also accurate enough to indicate any incomplete combustion losses of economic importance. Without doubt the loss due to large excess of air is the greatest one in the boiler room, and can usually be greatly reduced by making proper use of gas analysis. Before engineers in the isolated industrial plants can be induced to analyze for small traces of combustible gases, they must be first taught how to analyze for carbon dioxide (CO), and they must learn to appre- ciate the great possibilities of reducing loss from large excess of air. Furthermore, in the face of the great difficulty of obtaining a fair

Jan 1, 1915

By J. Litsenberger, T. E. Marshall, P. R. Coyle, L. J. Prosser, A. T. Iannacchione

For the first time in an underground stone mine, the relationship between roof movement and microseismic emissions was examined in conjunction with two distinct roof fall areas. As roof monitoring increases in acceptance and monitoring technology advances, the goal of providing reliable roof fall detection systems to enhance the safety of underground mine workers moves closer to reality. Instrumental to reaching that goal is the ability to interpret accurately and completely roof movement and microseismic emissions, which can serve as precursors to roof falls. This paper examines the capabilities of convergence and microseismic monitoring systems to better understand roof rock failure mechanics and to anticipate roof falls. An understanding of how these techniques are used and how they interact with each other is critical in developing the most effective ground control strategy for our nation’s mines.

By Larry Patts, Michael J. Brnich

Approximately 45% of U.S. coal is produced from underground mining. The use of diesel engines to power under- ground mining equipment has steadily increased over the past four decades in an effort to improve mine safety and productivity. Several advantages realized with the use of diesel-powered mining equipment in underground coal mines are listed in Table I. The primary disadvantage of using diesel equipment in underground coal mines is that diesel exhaust emissions can contaminate mine ventilation air. The major constituents of diesel exhaust are gaseous emissions (which include carbon monoxide, carbon dioxide, oxides of nitrogen, sulfur oxides and unburned hydrocarbons) and diesel particulate matter (DPM). The Mine Safety and Health Administration (MSHA) has incorporated threshold limit values for all gaseous components of diesel exhaust into their regulations. These have been established by the American Conference of Governmental Industrial Hygienists.

By R. V. Ramani, P. M. T. White, D. Sutton

This review of literature is centered around ore evaluation and reserve calculations as generally used in the mining industry. Methods of data interpolation were reviewed with the object of determining a method that would best suit the evaluation of under- ground coal deposits. Further, computerized data library concepts as related to geological data were investigated together with a brief evaluation of the data requirements for the total project. Additionally, computer techniques for the processing of geological data with a view to generate management information for decision making were reviewed including hardware and software availability. 2.1 Interpolation and Extrapolation of Data The importance of accurate estimates of value parameters in terms of their geographical and geological distribution within a, mineralized body has long been recognized in the evaluation of metallic and non-metallic deposits. As the factors which affect mineral distributions and associations are better understood, accuracy, and reliability of estimation increases. The ideal objective is to develop a deterministic model with the capability of accurately predicting the value at any geographical location. The most important value parameters requiring determination in any orebody are the grade and the quantity of ore that can be mined at the stated grade. These two parameters are modified or qualified by others which include physical dimensions and physical and chemical characteristics of the ore value. Therefore, the

Jan 1, 1974

Provide ear protection which allows normal, unaltered hearing at low noise levels, yet protects the wearer from excessive noise. The Approach: A commercial earmuff with integral speakers has been adapted with a special amplifier so that low sound levels are not affected, but higher noise levels automatically reduced. How It Works: The discriminating earmuff developed by the Bureau of Mines has two modes of operation. In the first mode, where input sound levels are less than or equal to 83 decibels, the wearer will perceive noise at its actual level. For inputs in excess of 83 decibels, the second mode of operation begins and the sound perceived by the wearer is progressively attenuated, or reduced, as the input level is increased. A recognizable difference still exists between two adjacent sound levels enabling the wearer to differentiate between them.

Jan 1, 1975

By F. W. Lee

Operating engineers and mining executives are interested in the science of applied geophysics, but are looking for a simple and understandable exposition of its problems, instead of dissertations which are becoming more and more involved and increasingly difficult to comprehend. It may be well to discuss the goal, the attempted methods of reaching it and the psychological motive, if any, tack of the science. Where does the subject of applied geophysics stand from the viewpoint of (1) the physicist, (2) the mathematician, and (3) the geologist? Fundamentally, the science aims at a differentiation of subterranean geology with the object of finding useful mineral products by the study of gravitational, magnetic, seismic, electric, and other fields which may be associated with the materials naturally or which may be applied to them. The more skillfully these fields are recognized, applied, and analyzed the greater will be the possibility of interpreting results in a way that will be remunerative both economically and scientifically.

Oct 1, 1931

By Lawrence Y. Marks

During the mineral survey of the Bob Marshall Wilderness and study areas by the author in 1971, 1973, 1974, and 1976 (Marks, 1978), the area designated Reservoir-North (RARE II No. H1-485) in January, 1979, (U.S. Forest Service, 1979) was examined, along with other lands adjacent to the earlier study areas. However, the 1978 open-file report covered only areas originally designated for study. The present report on Reservoir-North is based on earlier work. No work has been done in the area since 1976. Mineral Appraisal Reservoir-North RARE II area (No. H1-485) is in the Northern Disturbed Belt which has been identified as having high potential for natural gas accumulations and lesser potential for oil accumulations (Mudge, 1978). Oil and gas lease applications in the area, indicate interest by oil companies.

Jan 1, 1981

"INTRODUCTIONMany of the facilities and much of the equipment available to the Generic Mineral Technology Center for Respirable Dust are highly specialized and therefore, unique to the universities associated with the Center as illustrated in FIGURES 30 through 39.For example, a sample bank of 1300 U.S. coal specimens housed in the Coal Research Section, Deike Building of The Pennsylvania State University has been characterized for physical, elemental, mineralogical and maceral compositions. The results of this research have been used to initiate a study of the relationship between pneumoconioses and coal properties. Selected samples from this bank have been used in animal (primate) studies at the Milton S. Hershey (Penn State) and West Virginia University Medical Centers. These laboratory facilities for research in the medical and biological disciplines is state-of-the-art and includes a primate colony where dust research is currently underway. The Materials Research Laboratory and the Rock Mechanics Laboratory at PSU, and the Mechanical Systems Design and Control Laboratory, the Rock Mechanics Laboratory and the Mine Electronic System Laboratory at WVU are equipped for fundamental research on dust generation and characterization. While the majority of respirable dust research projects fall into these two categories, dust generation and characterization and interaction of dust and lung, there are other laboratory facilities available to the Center which are unparalleled in the type of equipment and expert personnel that they contribute to the program. The Mine Particle Laboratory located at the University of Minnesota and the Diesel Engine Laboratory at Michigan Technological University are examples. They house equipment and instrumentation that is unique to these facilities. much of it having been developed specifically for dust research by the research scientists there. The dust collection equipment and the fine particles measurement, characterization and analysis apparatus are essential to research in the areas of dust collection, particle characterization and diesel particulates. In addition to university laboratories, the research facilities of the National Institute for Occupational Safety and Health (NIOSH) are available to the Center through its relationship With West Virginia University."

Aug 31, 1989

The dust exposure of the longwall shearer operator is usually determined by his position relative to the cutting drums. The dust generated during cutting may travel up-wind, against the primary airflow, and be carried out into the walkway where it can contaminate the intake air for as much as 10 feet outby the shearer operator&apos;s controls. Thus, both head and tail drum operators are exposed to un-acceptably high levels of air-borne respirable dust. One Solution The latest generation of long-wall shearers has features that make the use of radio remote or umbilical (hard wire) remote control relatively easy to implement. Remote control can enable shearer operators to control machines from positions that are less dusty than normal control stations. With either type, the head-drum operator can now control the shearer from a position up to 20 feet on the intake-air side of the shearer, while the tail-drum operator&apos;s station is now located across from the head drum.

Jan 1, 1984

By R. B. Corbett

"INTRODUCTION Aluminum and manganese bronzes as a group, may be separated readily from other copper-base alloys by experienced sorters. However, separation of aluminum bronze from manganese bronze is generally a matter of guesswork, so that accurate separation presents a difficult salvage problem.Attempts at separation by the thermoelectric tester. 3/ which had proved successful in solving other sorting problems, showed in this instance that the desired separation was uncertain because of the wide range of composition allowable in each kind of bronze. If only one composition of each kind of bronze were used in industry, separation by the thermoelectric method probably would be simple. However; the variability in composition observed in commercial alloys is so great that the thermoelectric power of the one type frequently overlaps the range of values found for the other. As a result, specimens frequently are classified in the' wrong group.Separation of the two types of bronzes on the basis of measurements of magnetic properties on filings from the various samples also proved unsuccessful because the test results overlapped to such an extent that no clear-cut division could be obtained.Electrode potential measurements were made also on the aluminum and manganese bronzes in the hope of distinguishing between them. A drop of saturated potassium chloride solution was placed on the fresh surface of the metal and the tip of a calomel electrode introduced therein. The voltage generated was measured by connecting the electrode and the bronze part to a research-type potentiometer. Although the voltages generated by the manganese bronze parts were greater than those generated by the aluminum parts, the difference in the closest two sets of readings was not sufficient to warrant a good separation. When a concentrated potassium alum solution was used instead of the potassium chloride solution, a wider divergence of voltage was produced by the various bronzes, but unfortunately readings overlapped in several instances."

Nov 1, 1944

By K. L. Rubow

"Diesel exhaust and mineral dust concentrations have been measured for aerosols generated in the laboratory and as found in five underground coal mines- 3 utiliting diesel-powered hallage equipment and two electric-powered equipment. Two source apportionment techniques have been applied to differentiate between the mineral dust and diesel exhaust aerosol concentrations. The first technique, using a microbrifke uniform deposit impactor CMOUDI) for size selective sampling, is based on modeling aerosol size and the premise that the diesel exhaust portion of .the aerosol is predom1nately submicrometer and the mineral dust portion is mostly greater that one micrometer in size. The second technique, Chemical Mass Balance CCMB) modeling, was used to referee the analysis of diesel exhaust and mineral dust aerosol concentrations from the size selective sampling results. ,The MOUDI size distribution data were modeled to obtain parameters describing the fine and course fractions of the sampled aerosol and to estimate the contributions to each mode from both mineral ·dust and diesel exhaust aerosol sources. The results showed the size distribution of the mixed aerosols exhibited two definite modes with the minimum between the modes occurring at 0.8 um. For the diesel equipped mines, this analysts yielded an average value for the fraction of the fine aerosol attributable to mineral dust of 1 pct. Less than 5 pct of the coal mine diesel aerosol was found in the coarse size fraction. CMB analysis confirms the original premise for using aerosol size to separate diesel exhaust and mineral dust aerosol during sampling."

Jan 1, 1988

By C. B. Manula, R. L. Sanford, R. A. Rivell

This report describes the development and application of a rail haulage simulator that is readily adaptable for the analysis of a wide variety of operating problems. Various gaming, options have been integrated into the model structure which permit trial and error solutions from a computer terminal prior to capital committment in the actual operation. The high level of information retrieval available allows engineers and managers to develop production data which fit individual needs. In this report, emphasis was placed on the problem of organizing and performing the sequence of operations that are necessary to accomplish a complete mine materials handling simulation. Here, the Rail Haulage Sub-assembly was linked to the Production Sub-system to mine and move coal from seven operating sections to the intermediate and main-line track. The analysis was devoted to the problems associated with how the operating system performs and what alternatives were available to minimize idle times and hence increase productivity. In order to have some objective means of evaluating which of the alter- native methods for production was most appropriate, the choice was to replace the intermediate track with belt conveyors. Since the attempt here was to demonstrate model flexibility and not to establish the goals or trade-offs between computing objectives with which systems judgement must contend, no further alternatives were tried. This is left to management with the data and a problem to solve. Rail haulage simulation is not new, and several, operationally tested models are being used in practice (Bucklen, et. al., 1968).

Jan 1, 1974

Track and control the tram maneuvers of continuous mining machines by developing and evaluating a laser sensor system. Background Progressive technology has the potential to greatly improve mine-worker safety, helping to create a safer, better working environment for mine workers by keeping them away from the dangerous face area. To benefit from such technology, the Bureau is investigating remote, computer-assisted operation of mining systems for underground, highwall, and surface mining applications. A cornerstone for computer-assisted operation is an effective guidance system. Since there are no guidance systems on any commercial continuous miners (CM&apos;s), the Bureau it-self developed and tested a laser-based sensor system, based on a commercial sensor called Lasernet. The laser-based guidance system employs four laser scanning sensors at fixed locations in a mine entryway to report the angular coordinates of two cylindrical retro-reflective targets mounted on a CM. Using triangulation, a real-time microcomputer system processes the sensor data and updates the xy position and heading (h) of the CM five times per second. Using a simple control algorithm and communications interface to the CM control computer, the system also controls rotational and translational tram maneuvers.

Jan 1, 1992