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By Paul V. Mullins

Review and evaluation of all available data on the vapor pressure of car-bon dioxide at the ice point, including previously unpublished results obtained by the Bureau of Mines, are presented. Suggested corrections and adjustments to all the data yield an average value of 26,136.4 mm mercury. Indicated agreement is within plus 1 part in 8,000 to minus 1 part in 11,000. A novel pressure bomb in which a sample of pure carbon dioxide is placed and sealed by a diaphragm fluid separator and its use as a reference pressure standard for extended and repeated use in the calibration of deadweight gages is described.

Jan 1, 1966

By Thomas P. Mucho, David C. Oyler, Jim Pablic, Dennis R. Dolinar

A room and pillar coal operation in central Pennsylvania was experiencing roof cutters and long running roof falls caused by high horizontal stresses. The roof conditions created hazards for the miners, and caused several production panels to be abandoned prematurely. The mine requested assistance from the National Institute for Occupational Safety and Health (NIOSH) in applying the "advance and relieve" mining to reduce the affects of the horizontal stress during panel development. The "advance and relieve" plan that was developed called for removing a pillar on one side of the panel as it was being advanced, thus creating a cave. The caving then relieved a portion of the horizontal stress across the panel. Because the horizontal stress direction is key to the success of this method, stress mapping as well as mining experience was used to establish the direction of the horizontal stress. Subsequent field measurements provided an estimate of the stress magnitude. Three panels were mined using this technique, and good roof conditions were achieved in all these panels. Instrumentation was used to monitor the stress changes in the roof created by the cave. Stress relief of over 1,000 psi was measured 120 ft from the cave and to depths of 20 ft into the roof. The lateral extent of the stress relief zone across the panels appears to be about 400 to 500 ft. This case history has provided much insight into the practical application of the "advance and relieve" method discussed in this paper.

The Mine Safety and Health Administration (MSHA) defines an independent contractor as “any person, partnership, corporation, subsidiary of a cor-poration, firm, association or other organization that contracts to perform services or construction at a mine.” Contractors that perform specific types of work are required to report the number of employees who work at coal mines and noncoal mines.

Sep 1, 2007

By W. I. Nissen

As part of its program to provide technology for reducing undesirable environmental impacts of mineral processing operations, the Bureau of Mines developed the citrate process for desulfurizing industrial stack gases that contain from 0.1 to 2 vol pet S02. In this regenerable flue gas desulfurization (FGD) process, S02 is absorbed from cleaned and cooled industrial flue gas with a citric acid-sodium citrate solution. The absorbed S02 is subsequently reacted with H2S to precipitate marketable elemental sulfur and regenerate the solution for recycle. Laboratory investigations of process parameters provided information for designing larger scale continuous operations. Information gathered from operation of two pilot plants, one at a copper smelter and one at a lead smelter, confirmed the laboratory results. Data were obtained for design and construction of a commercial-sized demonstration plant at the George F. Weaton Power Station, Monaca, PA. A preliminary operation of the plant was demonstrated, under a cost-sharing Bureau-industry contract. This bulletin describes the citrate process and gives results of the laboratory, pilot plant, and demonstration plant studies, as well as corrosion investigations.

Jan 1, 1985

By H. Winkelmann

The author, who himself has worked inn the field with various types of torsion balances, expresses in the article his experience with the recently marketed Haff-Torsion-Balance. The advantages of practical work with Haff?s s torsion balance as compared with other types are mentioned. In spite of low weight and corresponding small dimensions (Model M = 23.5 kg., Model Al = 11.5 kg.) the sensitiveness is not less than that in the largest instruments. It is at 1.10-9, which is proved by calculations. A comparison with the corresponding values of other types of torsion balances (Eötvös, Askania, Gepege) is given. The mechanical features of the instrument are briefly described, and the balance is illustrated by a, cross section of it. -- W. Ayvazoglou. DETERMINATION OF THE ELEMENTS OF THE MAGNETIC AND GRAVITATIONAL FIELDS INDUCED BY AN INFINITELY LONG HOMOGENEOUS CYLINDER By G. A. Gamburzeff Gerlands Beiträge zur Geophysik, Band 19, Heft 2/3 Leipzig, 1928, pp. 210-230. The present work is a. contribution to the quastion of the reason for the magnetic and gravitational anomalies in the government of Kursk (Russia).

Jan 1, 1929

By James Pennington

[The Mining and Metallurgical Divisions of the Bureau of Mines, Region V, conducted an investigation in 1950-51 of the iron sulfide deposits in Aitkin and Carlton Counties, Minn. Twelve diamond-core-drill holes, aggregating 2,347 feet, were drilled in secs. 14 and 15, T. 46 N., R. 25 W., Aitkin County, to increase reserves of iron sulfides known to exist 2 miles southwest in secs. 28 and 29, T. 46 N., R. 25 W. Three diamond-core-drill hobs, totaling 561 feet, were drilled in Canton County, sec. 7, T. 46 N., R. 2 0 W., to check reports of the presence of a large sulfide deposit in that area. Mineral-dressing tests were made on cores from 10 holes drilled in Aitkin County. These included core from hole 21 drilled in sec. 28 and submitted by the Glen Development Co.]

Jan 1, 1953

By Lloyd A. Morley

This Bureau of Mines publication presents a comprehensive review of mine electrical power-system theory and practice. It discusses fundamental theory and the vital aspects to be considered in planning and designing mine electrical power systems. The report is divided into three major sections. The first presents the history of electricity in mining and the fundamentals of electrical phenomena and components. The second focuses on power-system components: motors, grounding systems, cables, and protective equipment and devices. The final section includes mine power-center equipment, switchhouses and substations, batteries, and mine maintenance.

Jan 1, 2003

By Oliver Bowles

The following discussion of waste rock utilization constitutes the fifth paper of the current series of reports on lime- plant quarry problems . As here tofore lime manufacturers are invited to cooperate to the fullest extent by supplementing the Bureau's information with the results of their own experiences and observations . Waste utilization is the key to success in many enterprises , and with a broader knowledge of this branch of the lime industry more economical operation is made possible . Your assistance in compiling additional data on this subject is solicited , and such assistance may be rendered by writing answers to the questions on the final page of this report .

Apr 1, 1923

By J. Ronald Lawter

The purpose of the work described in this report was to measure the effects of diesel engine emissions on the air quality of work areas in a coal mine. Concentration measurements of a number of diesel related air contaminants were made at the Martin County Coal Corporation Mine in Inez, Kentucky. Compounds measured included carbon dioxide, carbon monoxide, formaldehyde, nitric oxide, and nitrogen dioxide. In addition, concentrations of the two classes of odorous compound;, aromatic hydrocarbons, and oxygenates were obtained along, with aldehyde concentrations. Surveys were made of the mine by odor analysts to determine the perceived intensity of diesel-produced odors. It was found that the concentrations of the measured species were well below their Threshold Limit Values. Odor intensity levels in the moderate to strong range were observed in the mine.

Jan 1, 1977

By Bruce Cantrell, K. L. Rubow

"INTRODOCTIONMeasurement of the contribution of diesel exhaust to respirable aerosol in mine environments has become increasingly important because of current concerns over the occupational health effects resulting from exposure to diesel emissions. In response to this, the U.S. Bureau of Mines is developing and evaluating new sampling methods for measuring diesel aerosol in underground mines. Two such techniques are being studied by the Bureau, size selective sampling and Chemical Mass Balance (CMB) modeling. These techniques use measurable physical or chemical characteristics of a mine aerosol sample to infer the amount of diesel particulate material contained in the sample.Size selective sampling is being adapted for measurement of diesel aerosol by the Particle Technology Laboratory (PTL) of the University of Minnesota under sponsorship by the Bureau. 1 It is based on the premise that diesel and mineral dust aerosol can be physically separated by size and collected during sampling using inertial impaction. An independent effort by the National Institute for Occupational Safety and Health to develop a size selective sampling technique was also sponsored by the Bureau.The second technique, CMB modeling, is being developed by the Bureau as an alternative measurement technique to referee the results obtained using size selective sampling.3 It compares measured trace element ""finger prints"" of aerosol sources with similar profiles of mine aerosol samples. From these, the portions of the sample contributed by each source can be determined. Results of these investigations in underground coal mines have confirmed that diesel and coal dust aerosol are of different size and can be measured separately using size selective sampling techniques.A major difference in diesel usage among underground mines is the requirement for exhaust gas cooling systems in coal and gassy noncoal mines. Nongassy mines usually employ limited exhaust conditioning in the form of catalytic converters, which have limited effect on primary exhaust particulate. The cooling system in most general use in gassy mines is the water scrubber. This device has little effect on most of the gases but removes particulate material from the exhaust. 5 Because of this, exhaust aerosol characteristics in nongassy mines are expected to be different. To see if size selective sampling techniques can be used in such mines, the Bureau and the University of Minnesota conducted a second study in three metal and nonmetal mines, two nongassy and one rated as gassy."

Jan 1, 1990

By T. M. Ruff

A prototype mucking machine designed to operate in narrow-vein stopes was developed by Foster- Miller, Inc., Waltham, MA, under contract with the U.S. Bureau of Mines. The machine, called a compact loader-trammer, or minimucker, was designed to replace slusher muckers in narrow-vein underground mines. The minimucker is a six-wheel-drive, skid-steered, load-haul-dump (LHD) machine that loads muck at the front with a novel slide-bucket system and ejects it out the rear so that the machine does not have to be turned around. To correct deficiencies of the tether-remote-control system, a computer-based, radio-remote-control system was retrofitted to the minimucker. Initial tests indicated a need to assist the operator in guiding the machine in narrow stopes. An automatic guidance system that used ultrasonic ranging sensors and a wall-following algorithm was installed. Additional tests in a simulated test stope showed that these changes improved the operation of the minimucker. The design and functions of the minimucker and its computer-based, remote-control system are reviewed, and an ultrasonic-sensor-based guidance system is described.

Jan 1, 1992

By R. S. Olsen

The Bureau of Mines is engaged in research to recover aluminum from kaolinitic clay and other nonbauxitic domestic resources. As part of this work, calcined Georgia kaolin was prepared by a process that prevents slime formation and makes the leached residues fast settling and easy to filter. The leaching reaction for calcined kaolinitic clay in a 5 pct stoichiometric excess of boiling 23-to 26-pct HCI was found to be zero order. Rate constants based on the weight-fraction of aluminum in the clay were found to be between 0.095 and 0.15 min-1 depending on feed preparation and leaching parameters. The mathematical relationships between aluminum extraction and time for both batch and continuous, stirred-tank operations were derived and verified experimentally.

Jan 1, 1983

By E. A. Clarke

The vapor-phase section of the Coal Hydrogenation Demonstration Plant at Louisiana, Mo., was operated for the first time in April 1949. The run lasted only 10 days because of time limitation (pending plant dedication in May) and the small amount of charging stock available. The primary purpose of the operation was to break in and determine the operability of the equipment and to supplement the operators' classroom training with actual practice by operating the plant under mild conditions. A secondary aim was to obtain data on the hydrogenation of petroleum oil and lignite tar distillate at approximately 10,000 p.s.i. while making gasoline and Diesel fuel oil. Although the operations were carried out under conditions considerably below those used in the plant design, a great deal of experience and data was obtained. As it is not feasible at this time to conduct further vapor-phase operations on similar stocks, this report has been prepared to present and summarize the data obtained through this operation.

Jan 1, 1950

By R. D. Leitch

"The pollution of streams has received much attention during the last few years, and although there are many other and more serious forms of pollution, the problem of acid mine drainage is important in certain sections of the country, particularly in Pennsylvania. At the request of the United States Public Health Service the Bureau of Mines undertook to determine some of the factors contributing to formation of acid mine waters, the yearly variations in quantity and quality of drainage, effect of mining methods, and various other questions arising in connection with the problem; some attention was also given to its economic phases.In acknowledgment, the writer wishes to thank Dr. R. R. Sayers, Chief surgeon; A. C. Fieldner, chief chemist; and W. P. Yant, supervising chemist, health laboratory section of the Pittsburgh Experiment Station, all of the Bureau of Mines, under whose direction the work was conducted.Because no data of a like nature had previously been determined, and with the thought that such data would throw additional light on the general subject, a stream having a number of mines draining into it was selected for observation in both high-sulphur and low-sulphur bituminous-coal districts, as designated in commercial rating. These mines and streams were visited in both wet and dry seasons to note the quantity and variations in acidity of mine drainage and the subsequent effect on streams. Maps of these streams with the sampling points are shown in Figures 1 and 2. In a report of this nature a great deal of tabular data is best emitted, but reference to the maps will serve to indicate the factors that determined sampling points, such as tributary streams and gobs."

Sep 1, 1928

By D. A. Reynolds, J. D. Davis

"This work was begun in l928, with the cooperation of the American, Gas Association, and the Association contributed financial aid for that year and for the 4 years following. In 1933 financial aid was discontinued, but the Advisory Committee, under the able, Chairmanship of J. S. Haug, has continued to function through the years to the present date. Mr. Haug's annual reports have been published in the Proceedings of the American Gas Association. The purpose of this paper is to bring the index of coals tested by the Bureau of Mines-American Gas Association (EM-AGA) method up to date, to discuss development of auxiliary tests, and to outiline the uses to which the methods have been put in promoting the war effort.COALS TESTEDThe test methods developed with the advice of the Advisory Committee had been applied to 66 coals up to 1942, and an index giving the serial number, origin, and analyses of these coals was published as Bureau of Mines Technical Paper 637. Since this paper was published, 20 additional coals have been tested; the source and analyses of these coals are given in table 1. The table also refers to publications that have been issued. Complete series of tests at high, medium, and low temperatures,have been made on most of these coals, and blending tests with 20 and 30 30 percent of low-volatile coals have also been made at 900°C.; however a few low- and medium-volatile coals (60, 70, 74, 79, and 80) were bested,at high temperatures only. Those coals were mined in eastern Oklahoma and western Arkansas. The test work included low- and high-temperature assay tests, petrorraphic analyses, and plasticity tests since its inception; and for the last 20 coals of the series, expansion and oxidation tests have been made where applicable."

Jun 1, 1944

By John K. Owens, Wayne L. Howie

Mobile roof support (MRS) machines are used as roof support during pillar recovery in retreat operations in lieu of wooden posts, cribs, or hydraulic props. A Mine Safety and Health Administration-permissible load rate monitoring system was developed for the MRS by researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health. The system uses a dedicated embedded processor to monitor changes in pressure inside the hydraulic cylinders of the MRS through multiplexed data acquisition channels and converts these pressure changes to load rates that sequentially activate three load-rate-indicator lights mounted on the machine. Each light represents a different loading rate to alert mine personnel to dangerous conditions during pillar extraction.

By Clive Ellis, Brian Davies, Steven E. Mischler, Jon C. Volkwein

A primary means to reduce environmental levels of diesel particulate matter (DPM) exposure to miners is to reduce the amount of DPM emission from the engine. A quick and economic method to estimate engine particulate emission levels has been developed. The method relies on the measurement of pressure increase across a ?lter element that is brie?y used to collect a DPM sample directly from the engine exhaust. The method has been re?ned with the inclusion of an annular aqueous denuder to the tube which permits dry ?lter samples to be obtained without addition of dilution air. Tailpipe ?lter samples may then be directly collected in hot and water-supersaturated exhaust gas ?ows from water bath-cooled coal mine engines without the need for dilution air. A primary means to reduce environmental levels of diesel particulate matter (DPM) exposure to miners is to reduce the amount of DPM emission from the engine. A quick and economic method to estimate engine particulate emission levels has been developed. The method relies on the measurement of pressure increase across a ?lter element that is brie?y used to collect a DPM sample directly from the engine exhaust. The method has been re?ned with the inclu­sion of an annular aqueous denuder to the tube which permits dry ?lter samples to be obtained without addition of dilution air. Tailpipe ?lter samples may then be directly collected in hot and water-supersaturated exhaust gas ?ows from water bath-cooled coal mine engines without the need for dilution air.

By C. P. Bowie, George L. Gates

"INTRODUCTION Experience in drilling oil and gas wells has shown that the voidance of blow-outs, twist-offs, fishing jobs, loss of circulation, and heaving and caving of shale formations into the drill hole depends largely on how well the drilling-mud fluid serves its purpose. A possible method for the control of the drilling fluids may be seen from a study of the relation between the particle-size distribution and some of the important drilling-fluid properties, such as the ability to build quickly a relatively impervious mud sheath on the wall of the hole in the porous formations penetrated by the bit during drilling operations. In a wartime economy, which urgently requires conservation of steel, proper functioning of the drilling fluid is particularly important because, as Parks 4/ has stated, intelligent use of good drilling fluids makes possible drilling of wells for thousands of feet in open holes without the necessity of setting protective strings of casing to control the movement of salt water, gas, and troublesome formations into the borehole; consequently, especially in deep wells, of proper drilling fluids materially reduces the need for casing and lowers the cost of drilling and completing the wells."

May 1, 1942

By G. H. Martindill

Complex chemical and physical changes occurring during carbonization result in a heterogeneous system composed of gaseous, liquid, and solid phases, whose relative proportions and chemical compositions change constantly as temperature increases. Studies in which the participating variables are isolated and controlled should be useful in formulating the mechanism of coal carbonization. The most characteristic property of a coking coal is its ability to form a plastic mass at a certain stage of the carbonization process. During this period it is believed that fluidity of the coal influences the properties of the resultant coke. This report gives results of an investigation by the Federal Bureau of Mines of the influence of the maximum fluidity attained by the charge on the physical quality of the coke or char produced. As a first approach to the problem, researchers investigated high-melting-point pitches, which are relatively simple carbonaceous materials. The plastic properties of these pitches, prepared specially for this work, varied greatly; their fluidities, as measured by the Gieseler plastometer, covered most of the fluidity range characteristic of coking coals. Blending these pitches with increasing pro-portions of fine coke progressively reduced their fluidities. Coal-pitch and coal-coke blends also were treated; their fluidities were varied by changing their blending ratios. The various blends were carbonized in a small-scale carbonizer and the resistance of the carbonized residue (char) to abrasion was determined in a small-scale tumbler test, using the Roga drum.

Jan 1, 1960

By E. J. Murphy, A. P. Rowles, John C. Holtz

"INTRODUCTION The use of sheaths or hollow cylinders of flame-extinctive materials surrounding cartridges of permissible explosives has been developed during the last few years; the history of sheathed explosives in their salient development in Belgium was treated recently in a publication of the Bureau of Mines. 6/ This development is of great interest in explosives technology, for it holds possibilities of reducing further the ignition hazards that may cause many coal-mine disasters. The township interest in sheathed explosives in this country is attested by the passage of some State laws permitting the use of such explosives on shift 7/; inquiries are received in increasing numbers concerning the effects of sheaths on practical hazards as well as the general technology underlying their use."

May 1, 1943