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By C. S. Compton, D. R. Dolinar, D. C. Oyler

More than 80% of U.S. roof bolts are fully-grouted, but about 1500 roof falls are reported each year. Anchorage failure of a fully grouted bolt can occur when the roof is active near the top of the hole. This paper reports on an extensive series of short-encapsulation pull tests (in which the bolts are installed with only 1 ft of resin) that were conducted in the National Institute for Occupational Safety and Health (NIOSH) Mine Safety Research Laboratory and operating mines in WV and PA. The tests confirmed that poor anchorage can been countered under some weak rock conditions. Suggestions for improving anchorage are included.

By J. B. Gayle

In a modern blast furnace, production depends, to a large extent, on the rate at which the furnace gases can be forced through the charge. Since these gases must make their way through the voids between particles of coke, ore, and limestone, the size and size distribution of the stock-column materials are of considerable importance. Also, because the coke pieces support the weight of the overburden and provide the majority of the voids through which the gases pass, their ability to withstand the shattering and abrading forces to which they are subjected should be related to the maximum obtainable production for any particular furnace. Although the wide acceptance of this point of view is indicated by the ever-increasing demand for stronger and more uniform blast-furnace cokes, economic considerations demand that a quantitative evaluation of the relation between coke quality and blast-furnace performance be made available to the industry at the earliest possible date. The following studies of size-distribution patterns and breakage processes were, therefore, conducted as a part of a preliminary investigation intended as a basis for future studies of the relation between coke quality and blast-furnace performance. The major findings may be summarized as follows: 1. New evidence for the presence of two independent distributions of sizes in run-of-oven cokes has been obtained, and a method for characterizing and estimating the relative importance of the individual distributions has been demonstrated. This method has also been used to study the different types of degradation taking place during the tumbler test.

Jan 1, 1954

By Jr. Sillers

This is the third report of investigations dealing with the application of electrolytic manganese to steel-foundry practice and the seventh in a series of reports dealing with tests to establish the technological acceptability of electrolytic manganese in the iron and steel industries. The work was carried out by Metallurgical Division of the Bureau of Mines as part of an extensive program for the development and utilization of domestic ores. The electrolytic manganese used in the tests was produced by the Bureau at its Boulder, City, Nev., pilot plant by the process developed by the Bureau of Mines.

Jan 1, 1949

By Alexander Siefert, Steffen Pankoke

In the development of commercial vehicles as well as of passenger cars, the effects of vehicle vibrations on operating safety, health and comfort can only be predicted by numerical simulation when appropriate occupant models are available. Such models must be based on human anatomy and have dynamic properties of real humans in order to achieve realistic results. Since human dynamic behavior depend on posture and percentile, the occupant model needs to be adjustable to these parameters with respect to geometry and dynamic properties [1,2]. Dynamic Human Finite-Element-Model CASIMIR CASIMIR is a non-linear, dynamic finite-element-model of the human body. It consists of a dynamic model of the upper torso with head, neck, shoulders and arms as well as of a dynamic model of the lower extremity with pelvis and legs. The most important part is the lumbar area with dynamic non-linear models of the lumbar spine and of back and abdominal musculature. The frequency-dependent characteristics of the intervertebral discs and the effects of muscle activation and non-linear frequency-dependent muscle properties are included. In the latest stage of development, CASIMIR has been equipped with a compliant model of the body surface in the contact areas to the seat. This results in a very realistic transmission of static and vibrational forces into the human body, see fig. 1. Intense model verification and validation has been performed in all stages of model development, starting with validation of small components like intervertebral disc, ending with validation of whole-body-vibrations using measurements of the dynamic mass / mechanical impedance [4]. For an in-detail examination of stresses in the vertebral bodies and discs, a non-linear submodel of the lumbar spine with an increased number of degrees of freedom can be coupled to the whole-body-model, enabling the researcher to examine local effects of vibrations and single shocks on the lumbar materials. [ ] Since it is well known that human dynamic behavior is significantly affected by anthropometric data and posture, CASIMIR can be individualized to the anthropometric status of single individuals or to the mean values for specific percentile groups. Furthermore, posture can be adjusted to the seating conditions applicable to a specific vehicle. Posture modification capabilities include the variation of the lumbar lordosis [3].

Jan 6, 2006

By William T. Reid

Low-temperature carbonization of coal in Japan served as an important source of liquid fuels during the war. Six plants operating in Japan Proper produced 203,069 KL (53.7 million gallons) of liquid fuel from 1940 until the end of the war in August 1945, while four additional plants in Karafuto and Korea produced 211,943 KL (56.0 million gallons) for a total of 415,012 KL (109.7 million gallons) of liquid products. Semicoke produced in these plants was used for domestic fuel, for gasi- fication in portable gas producers on automotive vehicles, and to replace imported low-volatile bituminous coal in the manufacture of metallurgical coke. Since 1936 one plant had produced more than 300,000 metric tons of semicoke for blending with bituminous coal to form coke, while the total production of semicoke since the beginning of the industry in 1923 is approxi- mately 2,000,000 metric tons. Despite an apparent annual carbonizing capacity of about 2,000,000 metric tons of coal for the entire country, the maximum amount of scmicoke produced during the peak year, 1943, was 468,446 metric tons. The equipment used is primarily of Gorman design. Just before the end of the war, 6 plants using 20 Lurgi carbonizers were operating with a total rated capacity of more than 1,500,000 metric tons of coal per year, while 2 Koppors units had a combined annual rated capacity of 400,000 metric tons of coal. One plant using the Japanese-designed Mimura system was in service but with so much mechanical trouble that its output was small, while in another plant 4 Wanisht carbonizers of Japanese design but based on an early German development were running satisfactorily, and carbonizing about 100,000 metric tons of coal per year. A single installation of 15 American-designed Knowles ovens was operating near Tokyo but was carbonizing pitch for electrode carbon. ..! No true low-temperature process used in Japan could carbonize strongly. caking coals satisfactorily. The Mimura process designed for this purpose was unsuccessful, as was the Shimomura process before it, while the Lurgi, Koppers, and Wanishi systems operated only with noncaking or very weakly caking coals. The Knowles ovens, really a medium-temperature process, could carbonize-caking coal without difficulty...

Feb 1, 1948

By Joseph Blake Smith

Coal resource data from published sources and company files were used by the Bureau of Mines to determine the location and extent of strippable coal reserves in Wyoming. Total strippable reserves of 23 billion tons were estimated in seven major coal areas. Seven large strip mining operations were active in 1969, and their production totaled 45 million tons of coal. Cutoffs used to define strippable reserves were (1) minimum coalbed thicknesses of 5 feet; (2) overburden-to-coal ratios of less than 10 cubic yards of over- burden per ton of coal; and (3) total overburden thicknesses of less than 120 feet, except where reserves occur in multiple beds or a single thick bed. Tertiary rocks along margins of the Powder River basin contain most of the strippable coal reserves in Wyoming. The Wyodak beds, ranging in combined thickness from 30 to 1.30 feet, crop out on the east flank of the basin and contain an estimated 19 billion tons of strippable subbituminous C-rank coals under less than 200 feet of overburden. Partings between these beds total less than 60 feet. The 100- to 200-foot-thick. Healy bed on the western flank of the basin and the 35-foot-thick School and 20-foot-thick Badger beds on the south also contain large strippable reserves. Elsewhere in Wyoming, strippable reserves. Elsewhere in Wyoming, strippable deposits are subbituminous coal of Late Cretaceous and Tertiary ages, mostly in the Hanna and Great Divide basins in the south-central portion of the State and in the Kemmerer-Hamms Fork region in the southwestern corner.

Jan 1, 1972

By R. R. Sayers

Carbon monoxide poisoning, as usually encountered, is an acute condition resulting from breathing atmospheres containing that gas. It is characterized clinically by headache, dizziness, weakness in the legs, increased respiration at first which later becomes irregular and depressed, collapse, unconciousness, and death; anatomically it is characterized by temporary changes in the red blood cells due to the combination of carbon monoxide with hemoglobin, and, in prolonged severe exposures, degenerative changes in various tissues of the body, especially those of the central nervous system. No race or nationality is immune or has a, special tolerance for carbon monoxide. From data at hand, it is known that both sexes are about equally susceptible. All ages are affected, but small percentages seem to have a more deleterious effect upon young animals and this is possibly true of children. Exercise, high temperature and humidity, and low oxygen content of en atmosphere increase the degree of poisoning for a certain concentration of carbon monoxide. Anything that lowers the physical fitness of a man, such as illness, overwork, or excesses of any kind, exaggerates the effects. More cases of poisoning from carbon monoxide occur in coal mines in the cold months of the year, because explosions take place more frequently during that period, also in homes where gas is used for beating purposes, and in garages from accumulation of automobile exhaust gases due to poor ventilation.

Jan 1, 1923

REFERENCES AND FOOTNOTES 1. U.S. Department of the Interior, Office of Surface Mining. Surface Coal Mining Reclamation: 10 Years of Progress: 1977-1987. Washington, D.C. August 3, 1987.48 pp. (For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington D.C. 20402.) 2. The Rural Abandoned Mine Program (RAMP), authorized by Section 406 of SMCRA, provides for the control and prevention o f erosion and sediment damages from unreclaimed abandoned mine lands. 3. The Small Operator Assistance Program (SOAP), authorized by Section 401(b)(1) and 507(c) of SMCRA authorizes up to 10 percent of the fees collected for the Abandoned Mine Reclamation Fund to be used for technical assistance to help qualified small mine operators obtain techincal data needed for permit applications. Operators who produce fewer than 300,000 tons of coal per year are eligible for assistance. 4. OSM regulations 30 CFR 816.42 and 817.42 require water from areas distrubed by mining activities be in compliance with all applicable state and federal water-quality laws and effluent limitations for coal mining established by the U.S. Environmental Protection Agency. 5. Sourse: Abandoned Mine Lands Fee Collection System, Data from OSM-1 form. 6. Sourse: Abandoned Mine Lands Fee Collection System, Data from OSM-1 form. 7. Source: OSM Field Office Annual Reports. 8. Johnson, W. and G.C. Miller, Abandoned Coal-Mine Lands: nature, extent, and cost of reclamation. U. S. Bureau of Mines, 1979,29 pp. PHOTOGRAPHIC CREDITS Front cover, pp. i, 1, 2 bottom, 7 right, 10 bottom left, l 1 top, l l bottom right, 12 top, 13 bottom, 14 bottom right, 15,16 bottom, 17 top, 17 bottom right, 18 bottom, 19, 20 bottom, 21 top, 22, 23, 24 bottom, 25 bottom, 26 bottom left, 26 bottom right, 27, 28, 29 top, 30 bottom, 32 bottom right, 33 top, 34 top, 35 top left, 35 bottom left, 35 bottom right, 36 top, 37, top right, 37 bottom, 38 bottom, 39, 41, 42 top, 43 bottom, 44 bottom left, 44 bottom right, 45, 46, 47, and 53: Chuck Meyers, OSM. Page 2 top and center: Tony Fuhs. Page 3: John Sharkowicz, OSM. Page 6 left: North American Coal Corp. Pages 6 right, 7 left, l l bottom left, 13 top left, 13 top right, 17 bottom left, 21 bottom, 25 top left, 25 top right, 29 bottom, 30 center, 32 top, 32 bottom left, and 38 top: Bob Welch, OSM. Page 10 top left: Donald Stump, OSM. Pages 10 right, 14 top right, 14 center right, 18 top, and 44 top: Ron Hill, EPA. Page 12 bottom: Texas Utilities Co. Pages 16 top, 20 top, 24 top: Tennessee Valley Authority. Page 26 top right and 26 center left: Richard Dick, U.S. Bureau of Mines. Pages 30 top, 33 bottom left, 33 bottom right, 35 top right, 36 bottom, 37 top left, 40 top, 40 bottom, 42 bottom, 43 top left, and 43 top right: Jim Boyer, OSM. Page 31 top left, and 31 top right: Bruce Wage, Western Energy Co. Page 31 bottom: Rex Wilson, OSM. Page 34 bottom: West Virginia Division of Abandoned Mine Lands. Page 35 center: William Weist, Jr., OSM.

Jan 1, 1992

By Curtis H. Elder

In studies conducted by the Bureau of Mines, two test areas were hydraulically stimulated and exposed by mining: One in the Pittsburgh coalbed at the Vesta No. 5 mine, Washington County, Pa.; and one in the Illinois No. 6 coalbed at the Inland mine, Jefferson County, Ill. Induced fractures were contained totally within the coalbed with no adverse effect on the stability of associated rock strata. Induced fractures were vertical and were propagated normal to the direction of least residual tectonic stress. Gas production was increased fivefold to twentyfold by hydraulic stimulation.

Jan 1, 1977

By Albert L. Brautigam, Michael R. Yenchek, Jeffrey Shawn Peterson, James C. Cawley

The National Institute for Occupational Safety and Health investigated how the starting of induction motors may cause nuisance tripping of short-circuit protection on coal mine power systems. This research had a dual purpose: 1) to identify how motor-start waveforms differ from those for short circuits and 2) to devise a method to provide short-circuit protection without intentional time delays to account for motor starts. This technology will help ensure that surface temperatures of energized electrical apparatus will not exceed gas or dust ignition thresholds when short circuits occur.

By David A. Lipton

In 1980, the U.S. Bureau of Mines conducted a mineral survey of the 23,500 acre Garcia Mountain RARE II area (No. 5107) in the Los Padres National Forest. Bureau of Mines data indicate a low potential fur gold, silver, and mercury resources. Twenty-nine placer samples, representative of small yardages, showed small amounts of gold or other economic mineral values. Mercury deposits in faulted siliceous rocks in the Franciscan Formation occur north of the area. Similar rocks are in the southwest part of the study area, but apparently contain no mercury deposits. Geothermal and oil and gas potential is low.

Jan 1, 1982

By J. W. Thompson

The term "minerals" when employed in a conveyance in the State of West Virginia is understood to include every inorganic substance which can be extracted from the earth for profit, whether it be solid, as rock, fire clay, the various metals and coal, or liquid, such as salt, and other mineral waters and petroleum oil and gas. Horse Creek Land & Mining Co. v. Midkiff (West Virginia), 95 Southeastern 26, p. 27. TERM INCLUDES OIL AND OAS. The term "minerals" used to describe the interest in land granted or reserved bona fide includes petroleum oil and natural gas. Horse Creek Land & Mining Co. v. Midkiff (West Virginia), 95 Southeastern 26, p. 27. INJUNCTION TO PREVENT RElllOVAL. The removal of ore from the premises of another without his consent will be enjoined. Barnes v. Esch (Oregon), 169 Pacific, 512, p. 518. TITLE TO MEXICAN BULLION-JURISDICTION OF FEDERAL COURTS TO DETERMINE. Where bullion within the jurisdiction of the Mexican Government was seized, condemned, and sold for war supplies by the Constitutionalist forces in the revolution acting under authority from Gen. Carranza, claiming to be the provisional President of the Republic of Mexico, a United States district court of Texas, into which State the bullion has been imported from Mexico, has jurisdiction to try and adjudge as to the validity of the title acquired by and through the seizure, appropriation, and sale by the Carranza forces as against an American citizen claiming ownership of such bullion prior to its seizure.

Jan 1, 1919

By Jerry E. Olson

In 1984, the U.S. Bureau of Mines conducted a mineral survey of the Pahute Peak Wilderness Study Area (WSA) (NV-020-621), which covers 57,529 acres in Humboldt County, NV. About 90 percent of the WSA is underlain by Tertiary volcanic and shallow intrusive rocks. Of the remainder, metasedimentary rocks of unknown age are in contact with Cretaceous intrusive rocks in the northwest corner of the WSA. The entire WSA is within an upthrown fault block of the Basin and Range physiographic province. Portions of the WSA, especially south of Pahute Peak (Big Mountain), may be part of an eroded caldera structure. No mines or evidence of major exploration were identified within the WSA. Workings in Copper Canyon, claim blocks along the northwest boundary, and zones of anomalous character as defined by the Bureau of Land Management were examined. No mineral resources were identified, but sample results indicate three significantly mineralized sites, one with indications for zinc skarns in Copppr Canyon, another favorable for precious metals 2 miles south of Copper Canyon, and another area near the northwest boundary with geologic conditions characteristic of molybdenum deposits. Further investigation of these sites is warranted. Petrified wood is present in small amounts near the west central range front.

Jan 1, 1986

By Steven J. Page, Andrew B. Cecala, John A. Organiscak

In This Chapter [Drill dust control: wet and dry Enclosed cabs on drills and mobile equipment Haul road dust control] Overburden drilling generates most of the respirable dust that affects workers at surface mines. Both wet and dry methods are available to reduce this drill dust. Overburden removal by mobile excavation equipment such as bulldozers, front-end loaders, and haulage trucks can be dusty, particularly under dry and windy conditions. Tightly enclosed cabs with dust filtration systems can substantially lower the dust exposure of both drill and mobile equipment operators. Haul road dust control can be achieved by water application or chemical application. DRILL DUST CONTROL [Drill dust is controlled with wet or dry systems. Wet systems can be more efficient, but may freeze in the winter. Dry systems require careful maintenance of the drill deck shroud. An improved deck shroud is shown.] Wet Suppression. Wet drilling systems pump water into the bailing air from a water tank mounted on the drill. The water droplets in the bailing air trap dust particles as they travel up the annular space of the drilled hole, thus controlling dust as the air bails the cuttings from the hole [Page 1991]. In wet drilling systems, typical water flow rates are 0.1 to 2.0 gpm depending on the size and type of drill and the moisture level of the overburden. The drill operator controls the flow using a control valve located in the cab. Some drills are equipped with a flow meter to give the opera-tor a visual sign of the flow rate. Raising the water flow will improve dust capture, but too much water causes operational problems. Because of this, the drill operator must exercise care in find-ing the best water flow rate.

Jan 6, 2003

By L. D. Johnson

On a project which is to develop a system to suppress coal dust explosions, a facility has been built and several devices tested. The facility is a 317-foot, 4.5-foot diameter shock tube and to date 53 tests have been carried out with methane-air and methane/coal dust-air as the explosive mixtures. Suppression of slowly propagating (up to 300 ft/sec) flame fronts has been successfully carried out on two tests using the dry chemical extinguishing agent Purple K. Delivery of the material directly into the flame front Seems to be required if effective suppression is to be accomplished.

Jan 1, 1972

By J. Ritchey

This report describes the engineering feasibility and economic advantages of using a mobile bridge-type cross-pit belt conveyor system in conjunction with a large dragline to excavate and transport spoils in a typical Western surface coal mine. The studies show that such a system could be built to survive operational and climatic mining conditions, and that its implementation would offer a reduction in both acquisition and operating costs versus conventional mining units of comparable rapacity. Reclamation costs can also be significantly reduced, and the total reclamation process accelerated, making the cross-pit conveyor system attractive to mine Owners and environmentalists alike.

Jan 1, 1976

Collins Radio Company, through this contract with the Bureau of Mines, has conducted a System Study of Coal Mine Communi¬cations. The program was a three phase program to establish a data base, perform communication system analysis and optimi¬zation, and prepare equipment specifications to be included in this final report. At the start of establishing a data base both a knowledge of mine communication and coal mines in general was obtained. Communication system requirements and constraints were determined along with a survey of current and potential mine communication equipment. An investigation was completed concerning theoretical LF and VLF propagation characteristics, and UHF propagation tests were conducted in a working coal mine. Different mines were contacted and on-site surveys completed with respect to coal mine communication requirements.

Jan 1, 1973

By Susan B. Robertson, Gregory E. Hinshaw

Many injuries are caused each year by rock falls in coal mines. Most of these injuries are not caused by major roof collapses, but from falls of smaller rocks from the immediate top or roof skin. Various surface controls are used in mines to control this surface rock. One that has been found to be very effective is roof screening. Depending on the size of the screen, roof coverage approaching 100%can be achieved. Many mines are reluctant to use screen for primary skin control because of additional costs of time and materials, but others are having great success at both controlling costs and surface rock. Data is presented from two mines that show a dramatic reduction in roof skin injuries when screening is used. Much of this success is due to innovations in roof bolting machines. Four case studies of roof screen experience are presented along with associated costs of materials, impact on bolting advance rates, and potential ergonomic risks. The effects of roof screening on skin control and safety are also included. Finally, this paper will provide information about features of different roof bolting machines that affect production and safety.

By Michael W. Redifer

A Fortran IV computer program was developed to calculate the composition at equilibrium of products from a set of high-temperature gas combustion reactions. The program was used to develop high-temperature equilibrium concentration profiles for various constituents as a function of temperature and oxygen concentration. The computer program was specifically applied to reactions pertaining to the corrosion of superheater tubes in pulverized coal-fired boilers; however, it is useful for any multicomponent, multireaction scheme in which equilibrium constant data can be obtained and is comprised of gaseous reactants along with finely dispersed solids or liquids. General applicability of the computer program, including its limitations, are discussed along with detailed instructions for using the program.

Jan 1, 1973

By Michael Rieber

Among the principal gathering/distribution systems for coal is over-the-road trucking. Where alternative trunk line modes such as barge or rail links are weak or nonexistent, trucks may, particularly for relatively short line hauls, act as substitutes. Their major application, however, appears to be in connection with smaller mines or coal users particularly where terrain problems are significant. Truck use has increased as rail lines have been abandoned or suffered neglect. For example, in 1956 about 38 percent of the coal transported in eastern Kentucky and about 8 percent of the coal moved in western Kentucky went by truck. By 1975, the percentages were almost 77 percent and 26 percent, respectively [4,U-11]. While rail route .limitations and deterioration played a part in the change, increased emphasis on road building, particularly during the 1950's and 1960's, and improved truck load capacity and efficiency were also important.

Jan 1, 1977