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By L. Yuan, A. C. Smith

To provide insights for the optimization of ventilation systems for U.S. underground coal mines facing both methane control and spontaneous combustion issues, a computational fluid dynamics (CFD) study was conducted to model the potential for spontaneous heating in longwall gob areas. A two longwall panel district using a bleeder ventilation system with a stationary longwall face was simulated. The permeability and porosity profiles for the longwall gob were generated from a geotechnical model and were used as inputs for the CFD modeling. In this study, the effect of methane emissions from the mined coal seam, including the longwall face and overlying rider seam reservoirs on the gob gas distribution was considered. The spontaneous heating is modeled as the low-temperature oxidation of coal in the gob using kinetic data obtained from previous laboratory-scale spontaneous-combustion studies. Unsteady state simulations were conducted, and the effects of the coal’s apparent activation energy and reaction surface area on the spontaneous heating process were also examined.1

The development of an onboard contaminant diagnostic monitor to continuously measure contaminant level in a mining machine was advanced to a prototype stage in this contract. Several concepts were investigated and it was found that a static spool type sensor was the most reliable and accurate. Laboratory and field tests showed that an instrument based on this concept is capable of measuring contaminant levels and/or size distribution, depending on the configuration of the sensor. Moreover, this instrument can function on emulsions or homogeneous fluids. Current laboratory equipment can operate on homogeneous fluids only.

Jan 1, 1983

By Milton H. Fies

To present some idea as to how the Bureau of Mines may most effectively serve mining, it is necessary that we make some resume of its pact accomplishments in order to determine what, if any, changes will be of greatest service to the industry and to the nation. There are a great many times in life when one begins to wonder whether or not Emerson, in his famous epigram about "mousetraps" and "beaten paths" and "final recognition of intrinsic worth", took into account the item of time. The intrinsic value of any movement, of any work, of any accomplishment will ultimately be recognized, of that there is no doubt, but may a man in history has gone to his end in martyrdom because the world was slow in the acknowledgement of the true excellence of his worth, and this is likewise true of institutions.

Jan 1, 1934

By Henry Kreisinger, John Blizard, B. J. CROSS, C. E. Augustine

This report gives the results of 26 tests of a four-pass Edgemoor boiler fired with powdered coal at the Lakeside station of the Milwaukee Electric Railway & Light Co. The tests were made by the fuel section of the Bureau of Mines in cooperation with the research department of the Combustion Engineering Corporation and the operating department of the Milwaukee Electric Railway & Light Co. The object of the tests was to determine the thermal efficiencies and capacities obtainable by burning powdered coal under large central-station boilers, and the possibility of operating such boilers continuously at high efficiency and capacity without destructive effect on the furnaces and without difficulties in refuse removal. In any system for burning pulverized coal the furnace is the most important part because, to justify the cost of pulverizing, the powdered coal must be burned with higher efficiency than coal fired with mechanical stokers. In other words, it is the furnace that by giving higher thermal efficiency must pay for the installation, maintenance, and operation of the pulverizing equipment. No matter how simple the apparatus for the preparation of pulverized coal may be, or how simple the pulverizing process, unless the furnace is so designed that it can be operated continuously with high thermal efficiency, the whole system is a failure. For high thermal efficiency the coal must be burned almost completely with low excess air. But low excess air and complete combustion give high furnace temperature, which in turn causes erosion of the furnace lining and fusion of the ash; and removal of the fused ash is difficult. The necessity of complete combustion with low excess air thus brings with it these two important problems in the design of a furnace for burning powdered coal: 1, Prevention of erosion of the furnace lining; 2, easy removal of refuse from the furnace. For the purpose of solving these problems, the boiler tested was equipped with a furnace having hollow walls, through which about 60 per cent of the air needed for combustion passed before it entered the furnace. By passing through the hollow walls, the air cooled the furnace lining and prevented excessive erosion. A water screen was placed in the furnace about 3 feet above the bottom to keep the refuse deposited at the bottom from fusing and to make its removal easy. The design of the furnace, water screen, and burners was based on the experience gained in the previous cooperative tests1 with a smaller furnace, experimental water screen, and burners at the Oneida Street station of the Milwaukee Electric Railway & Light Co. The boiler tested had 13,057 square feet of heating surface. It was one of eight boilers fired with powdered coal, and was designated as boiler No. 8. The Lakeside station is the largest central station in the world that burns powdered coal exclusively. The coal used in the first five tests came from Illinois. The fuel in the other tests -:vas a mixture of Illinois and Pittsburgh coals.

Jan 1, 1925

By Graham W. Marks

In broadening the utility of spectrochemical methods 9f analysis of ore samples 3,4/ a procedure employ in the total energy method, has been adapted to determination of silver in ores. Silver is the first element in group I of the periodic table to be studied in the Bureau of Mines program. Two silver lines in the spectrum, Ag X\ 3280.683 and 3382.89lR were used in the study, and the problems that had to be overcome were: (1) Influence of extraneous elements on line intensities, (2) preparation of standard curves, and (3) improvement in equipment and technique to increase accuracy. Sodium, potassium, sulfur, selenium, iron, cobalt, and nickel yielded low intensities and hence low results, particularly on the samples high in silver, but addition of 60 percent or more of lime counteracted these effects. One calibration curve must be used for samples low in silver and other for those high in silver. The chocks with fire assaying were close enough for preliminary or exploratory investigations, and the method is much more rapid.

Jan 1, 1948

By John W. Buch

This is the first progress report to be released on the anthracite, mechanical mining research and engineering development program of the Bureau of Mines. This phase of Bureau work, which was initiated as an aid to stimulating wartime production of anthracite, has been continued after the war to assist primarily in improving the general economic position of the anthracite industry. Field work was started in. the 1945 fiscal year with the cooperation of an advisory committee representing management, labor, and the Commonwealth of Pennsylvania. For a beginning, several matters were suggested by members of this advisory committee as being worthy of investigation, and sections of underground mines yore offered for test purposes. Among the suggestions accepted for investigation was the problem of increasing the rate of advance for driving gangways in thin, steeply pitching anthracite beds 4 to 6 feet thick and pitching 60 degrees or more. The problem was undertaken as a field study, and this report relates to accomplishments on this project to June 30, 1947.

Jan 1, 1949

By Grant Buma

Groundwater restoration is an uranium leaching. Information on the technology, costs, and the current permitting regulations is of vital operators and to firms considering in important aspect of in situ effectiveness of the current state and federal government importance to in situ leach situ leaching. This study, funded by the U. S. Bureau of Mines, describes: (1) all recent restoration attempts at commercial in situ leach operations, (2) restoration costs reported by the industry, (3) empirical equations that predict the amount of groundwater flushing required to meet the current restoration criteria, and (4) in situ uranium permit requirements for the states of Texas, Wyoming, New Mexico, Utah, Montana, Colorado and South Dakota, and Federal requirements.

Jan 1, 1981

By H. B. Brunot, Ilsley. L. C., E. J. Gleim

"INTRODUCTION One of the various phases of the work by the U.S. Bureau of Mines, in its endeavors to minimize the hazards that attend coal mining, is the investigation of electrical motor-driven machinery. The object of this investigation is to foster the development of explosion-proof machines for use in gassy mines. This investigation is conducted under the provisions of Schedule 2C, which prescribes the inspection and tests made upon motors, controllers, and other electrical parts to determine their ability to withstand internal explosion without discharge of any flames. The method of conducting these inspections and tests is described in Bureau of Mines Bulletin 305, Inspection and Testing of Mine-Type Electrical Equipment for Permissibility, published in 1929. Formal approval of a machine for use in gassy mines is not granted by the Bureau of Mines until the machine is found to comply with the requirements, including inspection and test. When it is approved it is entitled to classification as a ""permissible"" machine.The high regard in which machines approved by the U.S. Bureau of Mines are held by engineers of other countries is attested by the growing number of shipments of permissible equipment; to other nations, including Australia, Russia, Norway, Japan, and Manchuria."

Aug 1, 1936

By E. G. King

Heat of formation values for mercuric sulfide appear in all the comprehensive listings of thermodynamic data, but experimentally determined entropy values have been lacking. Consequently, all free energy calculations involving mercuric sulfide have been based upon estimated entropy values. This paper reports Bureau of Mines measurements of the low-temperature heat capacity of red mercuric sulfide (cinnabar) and the entropy value at 298.15° K. derived therefrom. The entropy value was combined with heat data to obtain free energy values for the formation of red mercuric sulfide from liquid or gaseous mercury and from rhombic or gaseous diatomic sulfur.

Jan 1, 1962

By J. O. Lewis, Carl H. Beal

The material for this paper was collected for the most part by C. H. Beal during the years 1916, 1917, and 1918. Many of the conclusions reached in regard to the life of oil wells have already been published by the Bureau of Mines 1 but those presented in this paper deal particularly with the theoretical aspects of oil production. The report discusses some of the fundamental factors governing oil production, taking up first the conditions affecting the. amount of oil in the oil sand, then those factors that control the rate of production of oil wells, and then discusses several related problems, most of which deal particularly with the effect of the production of one well on that of another.

Jan 1, 1921

By J. C. Dumbrille

The following account of wining practices of the Kirkland Late Gold twining Co., (Ltd.), at Kirkland Lake, Ontario, is one of 4 series of papers being prepared by the United States Bureau of Mines on mining practices, methods, sad costs in various districts. The author has prepared this paper with the help and permission of J. B. Tyrrell and W. M. Sixt, the managing director and the mine manager, respectively. This mine is operating at a daily rate of about 150 tons.

Jan 1, 1931

By A. C. Fieldner

"Gas hazards may be divided into two principal classes- namely (1) inflammation and explosions; (2) asphyxiation and poisoning. Inflammation and explosion are prevented first by adequate ventilation so that gas sufficient to propagate flame or explosion can not accumulate, and second, by avoiding sources of ignition such as open lights, flames, sparks, electrical arcs, short circuits, or sparks. Ventilation is also the best preventive measure against asphyxiation and poisoning from toxic gases. When men must enter unventilated or poorly ventilated places containing poisonous or asphyxiating gases, suitable gas masks, hose masks, or oxygen breathing apparatus should be worn. As a rule, loss of life and property from gas hazards is due to ignorance of the properties and hazards of various gases commonly used, and consequently a failure to use proper measures for eliminating and meeting these dangers. It is the purpose of this paper to describe briefly the common gases and vapors with respect to the hazards involved in their use and to discuss the necessary precautions and methods for avoiding these dangersLight, heat, and power are prime essentials of our modern industrial civilization. The combustible gases and vapors used for the production of these necessary elements of our existence comprise the largest and most common group of domestic and industrial gas hazards. Almost every individual in his daily life subject to possible danger from asphyxiation, fire, or explosion due to one or more of these gases. For evidence one need only refer to the daily newspaper where headlines such as the following are frequently seen; ""Family asphyxiated by carbon monoxide from gas heater;"" ""Schoolhouse wrecked by gas explosion in basement;"" ""Man killed by automobile exhaust fumes in his garage;"" ""Fireman overcome by smoke fumes in basement ""Woman"".""Boman severely burned by accidental ignition of gasoline used in cleaning gloves;"" and 'in recent Years we often see ""Building wrecked by explosion of still in residential district.""It will be noted that these accidents are due to inflammation, explosion, or asphyxiation. Any combustible gas or vapor, when mixed, with air or oxygen within certain limiting proportions, will explode on ignition. The violence of the explosion varies with respective proportions of air and gas, and with the degree of confinement of the mixture. For example: Mixtures of natural gas and air containing between 4.5 and 12 per cent natural gas will explode, or propagate flame throughout the mixture without the continual presence of the source of ignition that started the inflammation. The table following gives the explosive limits of the common combustible gases and air:"

Jun 1, 1926

By C. M. McCulloch

A geologic study of Mines 32 and 33 in Cambria County, Pa., was conducted as part of a methane control research program. Areas of high methane emission and roof instability are encountered which are related to the structural and stratigraphic features that characterize the geologic setting of these mines. Locally the folds trend N 20° E ±2°, the direction of the butt cleat in the Lower Kittanning coal. The face cleat strikes at N 69° W ±2° and the systematic rock joint in the surface bedrock strikes N 67° W ±2°. This suggests that a directional stress oriented N 70° W produced the folds and influenced the directions of coal cleat and systematic joint sets. Analysis of SLAR indicates three directions of prominent regional lineation: N 39° E, N 31° W, and N 70° W. Little gas was encountered during development mining; large volumes of gas are encountered when roof falls. Most of the gas comes from strata above the mined coal; therefore, to control methane, roof instability must be controlled. Roof falls and high rates of methane emission are most likely where less than 30 feet of many thin layers of limestone, shale, and sandstone occurs between the Lower Kittanning coal and the next coal and in zones along the margins of a sandstone channel.

Jan 1, 1973

By N. A. Eilertsen

Mining operations were in progress at the Shawangunk mine near Summitville, Sullivan County, N. Y. as early as 1843 and again as late as 1918. Difficulty in effecting mechanical separation of sphalerite and galena was the primary reason for abandonment by various operators. The Bureau of Mines investigated this mine by diamond drilling, sampling, and performing beneficiation tests. The investigation included the construction of 1.25 miles of access road and the completion of 6,526 feet of core drilling in 24 holes. In addition, 151 samples were taken in the mine. The investigation proved an extension of ore contiguous to the old mine workings and resulted in the discovery of another ore shoot at depth. The ore occurs as fissure filling in a fault zone and contains concentrations of zinc and lead sulfides with minor dissemination of chalcopyrite in a quartz gangue. Metallurgical tests indicate that the ore can be concentrated by selective flotation.

Jan 1, 1950

The extremely cold weather and heavy snowstorms of January and February in northeastern Pennsylvania--with frozen mining equipment, diminished preparation and lack of railroad cars--severely hampered the production and distribution of anthracite. As a result, the previous estimates for the 2 months have been revised. On March 1, 1977, at the Porter Tunnel of the Kocher Coal Company at Tower City, Pa., an underground flash flood, which apparently broke through the wall of an adjoining abandoned shaft, swept through the mine. As of March 9, 1977, four miners were reported killed, three injured, and five trapped in the wreckage. The Kocher Coal Company began operations at the Porter Tunnel in 1968 and has had no fatalities until this current tragedy. The mine employs 20 persons on the surface and 115 miners underground, producing 750 tons of coal per day. Of the 109 underground mining operations in the anthracite region, this is the one remaining large mine that employs over 100 men.

Jan 1, 1977

By Brian M. Harney

The technique of remote sensing, used for many years by earth scientists, is being applied to the detection and monitoring of air pollution. Instrumentation being developed is of a very diverse nature and is effective, Fn varying degrees, at ranges from 1,000 meters to the altitude of a space satellite. This paper describes a number of the recent developments in this new field. Instruments based on spectroscopic, laser, and photographic systems are discussed. Sensors are being developed which utilize correlation spectrometry, interferometry, Raman scattering, Mie scattering, laser line absorption, and simple photographic detection.

Jan 1, 1973

By Christopher Mark, Gregory M. Molinda, Timothy M. Barton

The Coal Mine Roof Rating (CMRR) was first presented at this Conference nine years ago. Since its introduction, the CMRR has been incorporated into many aspects of mine planning, including longwall pillar design, roof support selection, feasibility studies, and extended cut evaluation. It has also become truly international, with involvement in mine designs and funded research projects in South Africa, Canada, and Australia. The purpose of this paper is to bring the mining community up to date with recent improvements and applications of the CMRR. The most important new development is a streamlined process for determining the CMRR from exploratory drill core. Just three types of information are now required: •Fracture spacing (or RQD) •Uniaxial compressive strength (or axial Point Load Testing) •Diametral Point Load Testing The moisture sensitivity adjustment has also been changed, and new research has related the immersion test to slake durability. Most recently, the CMRR has been implemented in a computer program, which can be obtained from NIOSH free of charge. The program facilitates calculation of the CMRR from either underground or drill core data. Values from many locations can be saved in a single file, and an interface with Autocad allows CMRR contour plots to be integrated into mine planning.

By D. Harrington

This paper is a revision of Information Circular 7380, by D. Harrington and J. H. East, Jr., published in 1946, entitled ?Safe Storage, Handling, and Use of Commercial Explosives in Metal Mines, Nonmetallic Mines, and Quarries.? Issued soon after the close of World War II, this earlier circular described the unprecedented increase in the production and use of commercial explosives during the war as a result of expanded industry and the tremendous demand f or metals and minerals. In the years following World War II, the production and use of commercial explosives in the United States have continued to rise. Hence, the Bureau of Mines presents these revised figures through 1952. In rewriting this Wormation circular, most of the text prepared by Harrington and East has been retained, with newer statistical information compiled by Seth T. Reese, Accident Analysis Branch, and V. E. Wrenn, of the same branch.

Jan 1, 1954

U.S. producers for more than 5 months have priced 99.5 percent primary aluminum ingot at 486 per pound. Sales by independent dealers in this same period reportedly declined by 0.5$-2.5$ to 43.50- 44.56 per pound. CADMIUM: U.S. producer-published cadmium prices for the last 5 months have been at $3 per pound. Dealer quotes in the same period fell by almost 504 and ranged from $2.45 to $2.55 per pound.

Jan 1, 1977

By Earl L. Fosse

"Preliminary examination of the Khayyam mine indicated that greater reserves of copper might be found by trenching, sampling, detailed geological and topographical mapping, and diamond drilling. The deposit seemed to be a potential source of sulfur, also, for use in the manufacture of paper pulp.Formal examination of the Khayyam mine by the Bureau of Mines was a follow-up of a preliminary examination made by W.S. Wright and the author on October 19-21, 1944. John Reed and W. S. Twanhofel, of the Geological Survey, visited the property during the summer of 1943 and suggested that the prospect be examined further.Preliminary examination of the Stumble-On claim was made July 1-3, 1945, concomitant with the formal examination of the Khayyam mine 11/2 miles to the west.In its program of exploration of mineral deposits, the Bureau of lanes has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy, It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts pre¬liminary examinations, performs the actual exploratory work, and prepares the final report, The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches arc under the supervision of Dr. R, S. Dean, assistant director.Special acknowledgment is due Robert S. Sanford, acting chief, Alaska Division, Mining Branch, for his help in the preparation of this report and during the project work.The Khayyam property is situated at 550 18’ north latitude and 1320 24’ west longitude on Prince of Wales Island in Southeastern Alaska. (see fig. 1.) The mine adit is 2,350 feet above sea level, near the summit of a mountain ridge, and 2.8 miles in an airline southwest of the head of McKenzie Inlet, a southern branch of Skown Arm. Skowl arm is navigable by ocean-going vessels .to the mouth of McKenzie Inlet, where reefs and rocky islands limit the channel width to 50 yards. Beyond this point the inlet widens to nearly half a mile. Coast and Geodetic Survey chart 8142 indicates from 12 fathoms of water at this narrow neck to more than 30 fathoms throughout the remainder of McKenzie Inlet, The old ore bunker and dock at the head. of the inlet are beyond repair. A new ore bunker and dock would have to be built if a large-scale mining operation were established.The mine can be reached by trail along the western ridge that lies on the west bank of Omar Creek. The trail is approximately 4 miles in length. The grade is rather steep to an elevation of 1,500 feet, but the last 21 miles can be traveled over gentle slopes along the crest of the ridge.Ketchikan is 30 miles by air and 42 miles by water from the head of McKenzie Inlet. Feed, hardware, fuel oil, lumber, and explosives can be purchased at Ketchikan and delivered by boat to McKenzie Inlet. By using an airplane, all small equipment and camp supplies could be using an airplane, all small equipment and camp supplies could be dropped with cargo parachutes near the mine."

Sep 1, 1946