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By Nicholas G. Theofilos

The only mining activity in Belize during 1976 involved the production of construction aggregates, which were used domestically. A comprehensive ordinance regulating mineral prospecting and mining was proposed during the year. Under the ordinance, which would supersede all grants and titles, ownership and control of all minerals except petroleum would be vested in the Government. Exxon Corp. entered into an agreement with three oil companies to achieve a majority interest in nine oil prospecting leases covering 1 million acres, mostly offshore Belize. The agreement was with Weatherford International Inc. which had 30% interest in the leases, Ajax Petroleum Co. with 40% interest, and Canadian Superior Oil Ltd, with 24% interest. A new entity, Esso Ventures Inc., was established to be responsible for conducting extensive geophysical operations and drilling an exploratory well offshore Belize.

Jan 1, 1980

1. Domestic Production and Use: In 1974 twelve companies operated 31 primary aluminum reduction plants, three firms accounting for 64% of production. Washington, Oregon, and Montana accounted for 32% of the total production; Gulf Coast States, 24%; Northern States, 33%, and other Southern States 11%. Output of primary metal in 1974 was valued at $3.4 billion. About 80% of the secondary recovery was from new aluminum base scrap and 20% was from old scrap. Aluminum consumption by 25,000 firms was centered in the East Central United States. Of aluminum consuming industries in 1974, building accounted for about 27%; transportation 19%; electrical, 13%; packaging, 15%; and consumer durab1es, 9%.

Jan 1, 1975

By Daniel I. Carey

Current and potential dragline reclamation usage was evaluated for the U.S. coalfields based on data gathered and analyzed during field surveys, literature reviews and contacts with manufacturers. It was concluded that current wining plans have been adapted to federal and state strip mine and reclamation laws in ways which limit the potential for drag line reclamation systems at active mine sites. At abandoned conventional contour mine sites in steep-sloping areas such as central Appalachia, however, it was found that dragline reclamation systems have great potential application and may be the only practical solution to many reclamation problems. Alternative dragline systems were examined for restoring abandoned sites, and it was concluded that a tower excavator system offered superior characteristics and should be evaluated and developed under field conditions. A testing program was developed to provide a framework for the monitoring and analysis of cost, production and environmental data during a field demonstration of a tower excavator system.

Jan 1, 1981

To improve communications between mine workings and surface locations during emergency situations and for administrative purposes. The Approach: Development of a device for interconnecting phone systems which permits two-way communication between a public telephone and a mine pagerphone by authorized personnel. How It Works: The system, developed by personnel at the Bureau's Pittsburgh (Pa.) Mining and Safety Research Center, makes connections between the public phone line and mine pagerphone line. As shown in Fig. 1., incoming calls are sensed by the ring detector (4) and the system "answers" the call electronically. To reach the pagerphone system, the caller inserts an audible tone of fixed frequency through the microphone of his telephone. This tone is produced by a miniature, pocket-carried tone generator and is detected by a tone recognition circuit (5). When this hap-pens, relay, switching, and logic circuitry (6) closes the connections between the two phone systems. Simultaneously, a page activator (9) places a DC paging voltage on the mine phone line.

Jan 1, 1974

By Jeffrey Shawn Peterson

The testing procedures of the U.S. Mine Safety and Health Administration specify that intrinsic safety acceptance tests be conducted using a standard tungsten-cadmium electrode configuration in the break- flash apparatus. However, in realistic mining environments, other materials may be more likely sources of sparking. Information defining the probability of spark ignition between common materials such as aluminum, brass, copper, lead, tin, cold-rolled steel, and stainless steel is of more practical value in determining ignition hazards. The U.S. Bureau of Mines has completed an investigation of the influence of material on the ignition probability using the breakflash apparatus. By comparing ignition currents or ignition voltages corresponding to a probability of one ignition per thousand sparks to those found previously for cadmium, a margin of safety may be estimated for each material. This report presents the results of an investigation into the influence of disk electrode material on the probability of ignition.

Jan 1, 2002

Helium has probably aroused more varied scientific curiosity than any other single element. Discovered by spectroscopic examination of the sun during an eclipse in 1868, helium is now known to exist not only in the sun and other stars but on earth occluded in minerals, accumulated with natural gases in pockets in the earth's crust, and in the atmosphere surrounding the earth. Astronomers study its presence in the various stars of the universe for clues to their origin and history. Geochemists and geologists study its occurrences in rocks, minerals, and meteorites to determine the age of the earth and the manner of its formation. Pathologists study its effect on living tissues in search for the ideal combination with oxygen for artificial breathing mixtures in medicine, diving operations, and space vehicles. Chemists study its physical properties and use it to trace the sequence of events in reactions in which it does not participate. Geneticists and bacteriologists use it for special studies. Physicists study its behavior when liquefied and the behavior of materials cooled to nearly absolute zero by its use. Nuclear physicists learn more about the universe through study of the nuclear reactions that produce it. Through study of helium and greater knowledge of its origin and properties, science continues to unlock some of nature's more closely guarded secrets. Unknown on earth before 1895, and not discovered as a minor constituent of natural gas until 1905, helium with its simple atomic structure--a nucleus with two electrons orbiting in a closed shell--is a unique element. It is next to the lightest gas, only hydrogen is lighter. It occupies position number 2 in the Periodic Table of the Elements and heads the list of so-called "rare" or ?noble? gases. Most of the naturally occurring helium has an atomic mass of 4.003874 (oxygen = 16). A trace (1.7 x 10-5 mol percent) is the light isotope helium-3 whose atomic mass is 3.0169800 Unstable isotopes of mass numbers 5 and 6 have been authenticated. Isotopes of mass numbers 7 and 8 have been reported, but their existence is less well established. All the heavier isotopes are radioactive and are the product of nuclear reactions.

Jan 1, 1968

By S. F. Mauser

This report describes the study of factors which affect medium voltage (661 - 1000 volts) trailing cable splices used in underground coal mines. Improvements in quality, dependability, and design of splice kits and shop splices are presented in the study results and recommended guidelines and regulations. Recommended research programs are included which describe approaches for development of the recommended guidelines and regulations for medium voltage trailing cable splices. The basis for the conclusions and recommendations presented in this report is included in three appendices which describe a survey, splice examination, and general requirements development prepared during the progress of this study.

Jan 1, 1977

By Allen McComas, Frank Chase, Phyllip Worley

Longwall mining has gained the reputation as being the safest extraction method in underground coal mines. However, one of the most difficult tasks associated with longwall mining is moving the face once a panel is completed. Based on Mine Safety and Health Administration (MSHA) fatality reports since 1996, longwall face recovery operations have claimed the lives of 5 U.S. miners and have resulted in numerous injuries. Recovery operations can be hazardous because they involve moving large pieces of equipment in very confined spaces. They are also conducted in highly stressed ground conditions due to front abutment loads generated by panel extraction. Shield removal is the most hazardous operation during face recovery because miners are constantly exposed to the unpredictable gob edge. To protect the miners, one or more walking shields, cribbing and/or other supplemental roof and standing supports are typically employed as breaker line supports as each shield is removed. At the Harris No. 1 Mine in southern WV, mobile roof supports (MRS’s) have been used in lieu of traditional walking shields on 17 face moves since 1997. MRS’s are shield-like support units mounted on crawler tracks and are commonly used during room-and-pillar retreat mining operations. For longwall recovery, the two biggest advantages that MRS’s have over traditional walking shields are that they are remotely controlled and are highly maneuverable. MRS’s have contributed to safer shield recovery and shorter move times at the Harris No. 1 Mine. This paper will address both the safety and the operational issues associated with MRS usage during shield recovery. It will also discuss new developments, including the use of the inherently safer battery powered MRS’s, which have been recently certified by the Mine Safety and Health Administration.

The Bureau of Mines has reviewed those portions of the "Tariff Schedules of the United States Annotated 1963" that are of interest to the minerals industry. This study shows to what extent rates of duty were altered (increased or decreased), and provides a bridge where possible from the old Schedule A classification sys tem to the new TSUS system of statistical reporting of import data. In general the new tariff has corrected previous classification defects and inconsistencies, but the rates of duties have not been materially changed.

Jan 1, 1965

Duties on Lead Imports from Mexico. - On September 15, the President signed Proclamation 4792 suspending concessions formerly granted as of January 1 on red lead imported from Mexico. The Proclamation also increased the duty payable on litharge imported from Mexico from 3% ad valorem to 3.5% ad valorem, effective September 15. Appeal of Lead Standards. - The U.S. Court of Appeals for Washington, D.C., rejected petitions by the Lead Industries Assoc. and St. Joe Minerals Corp. for a review of standards promulgated by EPA and OSHA. The Lead Industries Assoc. reportedly will appeal to the U.S. Supreme Court on the basis of the "benzene" and "cotton dust" decisions. Scheduled implementation of standards will continue during the appeal.

Jan 1, 1980

By Slavoljub Makslmovic

One important element of the U.S. Bureau of Mines computer-assisted mining research program is the development of a reliable coal interface detection (CID) system. Several candidate CID concepts currently being investigated by the Bureau include use of natural gamma radiation (NGR), vibration, passive infrared, video, and radar. To help establish which CID sensor technologies need to be developed for a given seam, the Bureau has collected geological and mining practices data from over 460 underground and surface mines in the United States. Also, over 500 coal and rock samples have been obtained for laboratory analyses of ash content, sulfur content, heating value, and NGR. The Bureau's findings indicate that the immediate roof strata in 81% of the underground mines and 93% of the surface mines are made up of shale, draw slate, or claystone. The immediate floor strata in 88% of both the underground and surface mines consist of fireclay, shale, draw slate, or claystone. The results of the NGR testing indicate that the NGR method appears to be a potentially useful CID tool, provided that the immediate roof and floor are both composed of a high percentage of shale-type material.

Jan 1, 1993

By A. B. Hooker, E. J. Coggeshall

"Dry cells are modified wet primary cells in which the electrolyte is held by absorbent material so that it does not spill aid the cell jars are sealed to prevent evaporation of the absorbed electrolyte. Most dry cells in commercial use are modifications of the Leclanche wet cell. In their usual form they have a hollow cylindrical zinc negative pole that constitutes the containing vessel. An absorbent material, either as a lining in the zinc jar or a bag, separates the zinc cylinder and a rod or flat plate of carbon placed axially inside. A mixture of crushed coke, graphite, and manganese dioxide is tamped about the carbon rod, and the whole mass is saturated with salaanoniac-zinc chloride solution.Dry cells are suitable for services that require minute currents continuously or larger, though limited, amounts of current intermittently. Though limited in this way, they have a wide use, even in underground mining. This paper details some of the applications of dry cells in mines, particularly from the standpoint of greater safety through their use.APPLICATIONSThere are four fields of application of dry cells to mining: (1) Electric shot firing; (2) auxiliary lighting; (3) signaling; and (4) testing.SHOT FIRINGFiring an electric detonator requires very little electrical energy because although the current flow may be 1 to 3 amperes the duration of flow is so small (1 to 4 milliseconds) that the energy withdrawal per shot is almost negligible. Batteries for shot firing need not be large; they may be used for firing either single or multiple shots."

May 1, 1934

By Warren M. Mahan

A rotary kiln process was developed by the Federal Bureau of Mines to produce consistently an iron product containing 3 to 7 percent nickel. Cuban laterite and serpentine ores were smelted in a gas-fired batch-rotary kiln) 5 feet in diameter and 9 feet long. The metal contained 2 to 4 percent carbon, with little or no silicon, and could be produced on a large scale with modest capital investment. A total of 121 tests was run using this procedure. The tests were conducted with a maximum temperature of 2,625° F., using linings of firebrick containing 40 to 70 percent alumina. Slags in the kiln were acid to neutral. The material in each batch passed through three stages: (1) Sponge metal, (2) carburization, and (3) balling and meltdown. Half the tests were made while firing the kiln with atmospheric-temperature air; the remainder were fired with preheated air. Tests showed that preheated air decreased fuel requirements, dust losses, and reducing agent, and increased the capacity of the kiln.

Jan 1, 1960

By J. A. Markovits

Coal has been hydrogenated in Germany on a lather extensive scale for the past 20 years, but the process is new to the United States. Although pressures up to 15,000 pounds per square inch have been employed on commercial scale in the synthesis of anhydrous ammonia, and there is evidence that valves, tubing, and equipment have been developed recently up to 30,000 p.s.i. working pressure at moderately elevated temperatures for limited industrial production of plastics, such pressure ranges are unusual in American industry, and equipment designed for them is not commonly available. In the Coal Hydrogenation Demonstration Plant at Louisiana, Mo., 10,000 p.s.i. operating pressures are combined with temperatures up to 1,000° F., and the materials to be processed under these conditions range from gases to mixtures of viscous liquids containing high percentages of abrasive solid particles. These service conditions presented unusual engineering problems requiring thorough investigation, Limited financial resources arid rigid time schedules inherent in the synthetic liquid fuels act often forced decisions before the best answer to a problem could be developed. Sometimes the ideal technical solution proved to be beyond the financial limitations of the demonstration-plant program.

Jan 1, 1949

By G. L. Oldright, Virgil Miller

"This paper is the tenth 4 of a series on smelting in the lead blast furnace, and the fifth 5 on modifications brought about by the introduction of richer charges.ACKNOWLEDGMENTSAll of the data on handling rich charges in lead smelting given in this recent set of five articles describing the results of a cooperative study by the United States Bureau of Mines and the University of Utah were obtained through the courtesy and with the cooperation of the staff of the Bunker Hill & Sullivan Mining & Concentrating Co. at Kellogg, Idaho. The authors acknowledge with appreciation the assistance given by Stanly A. Easton, vice.-president and general manager, F. M. Smith, smelter director, and A. F. Beasley, smelter superintendent, whose generosity, sympathy, and assistance made it possible to obtain this information for the mining industry.GENERAL DISCUSSIONWhen the charge has been dropped into the lead blast furnace, it is out of control of the operator to the extent that, whatever the material is, it must practically all be melted and run out of the blast furnace. The necessary uniformity of mixture to produce slags of regular composition and the choice of the slag—forming ingredients and products to be formed can be made only before the charge to dropped.It was found (R.I. 3096) at Kellogg, where the charge is mostly sinter, that the ratio of the slag—forming ingredients taken from each tuyere was nearly constant, in contrast to the irregular composition of slags taken similarly from a furnace whose charge consisted of ingredients differing greatly in chemical and physical nature, including size. If the charge consists almost entirely of sinter, the blast furnace should then operate more uniformly."

Aug 1, 1932

By Larry A. Haas

The U.S. Bureau of Mines is investigating ways of enhancing the high-temperature softening-melting (HTSM) properties of domestic taconite pellets. These properties, which are important for determining the performance of pellets in blast furnaces, include pellet bed contraction, pressure drop, S-value (area under the pressure-temperature curve), and softening and metal-slag drainout temperatures. Experiments showed that HTSM properties were related to the physiochemical properties (fired strengths and reducibilities) of pellets containing different levels of limestone and dolomite flux. Flux additions resulted in slightly lower green and fired pellet strengths, but improved metallurgical properties, such as reducibility. The influence of reduction conditions on HTSM properties was evaluated by varying the pellet metallization starting temperature and the carbon monoxide content of the CO-N2 gas mixture. HTSM property change was more sensitive to flux addition levels when metallization was initiated at 1,100° C with 20 pct CO in the gas stream. The S-value and the metal-slag drainout temperature were found to be the best criteria for characterizing HTSM properties. The optimum flux addition level was about 8 pct (4 pct dolomite, 4 pct limestone) or a basicity of about 1. At higher flux levels, a higher metal-slag drainout temperature was obtained.

Jan 1, 2010

A major domestic aluminum producer raised its price for primary aluminum metal from 44 cents per pound to 48 cents per pound, effective August 5, 1976. Other major producers have increased their list prices by equivalent amounts COAL: The strike which began July 19 in southern West Virginia enlarged by early August to involve approximately 80,000 miners in nine States. As of August 4, the aggregated loss of production is estimated to be 5.8 million tons. Reportedly, at this time, the railroads which serve the struck areas are feeling the largest impact with coke plants and electric utilities relying on stocks which are generally high.

Jan 1, 1976

By G. W. Luxbacher

This volume describes the use of the Penn State Mine Ventilation Simulator (PSU/MVS) to model existing mine ventilation systems and, in addition, to evaluate the effect of system modifications. Ventilation survey methods designed to insure computer input data of sufficient accuracy for simulation purposes are covered in comprehensive detail, including quantity and pressure measurement and fan performance testing. The development of input data from ventilation survey results is discussed and illustrated by the use of an actual field survey. Two programs, written in FORTRAN IV with WATFIV, are presented to calculate airway head losses from altimeter pressure measurements. An existing coal mine ventilation system is analyzed and modifications to the system are simulated and evaluated. In addition the application of the PSU/MVS to non-coal mines is briefly discussed. An extensive bibliography on ventilation surveying and simulation is included.

Jan 1, 1977

By R. G. Knickerbocker, T. E. Evans, D. R. Torgeson

"INTRODUCTION Sponge iron is a product resulting from the reduction of an iron oxide at such a low temperature that fusion does not occur, and the reduced particles retain substantially the same shape as the original ore. The removal of oxygen in the reduction process leaves the metal porous and reactive. Sponge iron may be compared in general to a chemically precipitated substance insofar as reactive properties are concerned. The high specific surface and the orientation of metallic structure are factors which probably contribute to the reactive properties of sponge iron.The term ""gaseous reduction,"" as applied to iron ores, required clarification. Strong evidence exists, for example, that ore is partly reduced to sponge iron by carbon monoxide in the blast furnace at temperatures around 800° C. at a point that may be as high as 30 feet above the tuyores. In 1923 and 1924, Sims and Wood attempted to reduce iron oxide with carbon in an Arsem vacuum furnace at 980° C. These investigators found that only 6 percent of the iron was reduced to metal when the iron oxide-carbon mixture was heated for 1 hour under evacuated conditions, whereas at atmospheric pressure 70 percent of the iron was metallized. Their results indicate that the process of iron-ore reduction at temperatures below the melting point of the ore may proceed largely, if not entirely, by the action of reducing gases even when the reducing agent is solid carbon. Therefore, the term ""gaseous reduction,"" as used heroin, is defined as a process in which iron ore is brought into intimate contact with a reducing gas produced in separate-equipment from the reduction chamber itself.A large amount of pilot-plant development on gaseous reduction of iron ores has been carried out by the Bureau of Mines at the Boulder Experiment Station and had as its objective the reduction of fine iron ore by means of producer gas. The use of use gas was prompted by two considerations: First, the possible utilization of large reserves of Western noncoking bituminous coals and lignites contiguous to iron-ore drewwing; and second, an investigation of the results that might be achieved in the pilot-plant gaseous reduction of fine iron ores by means of a relatively reducing gas. The results obtained, it was felt, would be of considerable value in indicating the direction which gaseous reduction experimentation must take for the development of a commercially practicable and economic process for the production of sponge iron."

Dec 1, 1946

By Edgar S. Rush

This study was conducted to make a limited evaluation of experimental and standard tractor dozer blades. A field test program was conducted in the southeastern part of Kansas on strip-mined areas where the spoil banks are parallel with rest-to-crest distances between 90 and 120 ft and maximum dozing distances usually less than 50 ft. This evaluation was a part of an overall joint Pittsburg and Midway Mining Company--U. S. Bureau of Mines (USBM) Specialized Reclamation Field Test Program primarily centered on the field t sting of experimental high-volume lateral relocation blades. The three blades evaluated were the 60-ft-wide angle (A) blade mounted on two 41B tractors. a 48-ft-wide A blade mounted on two D9H tractors, and a 13-ft-wide reclamation universal (Rec U) blade mounted on a D9H tractor. In addition to the experimental blades, three commercially available blades were tested: A 20-ft universal (U) blade mounted on two side-by-side (SxS) D9H tractors; a 20-ft U blade mounted on a 418 tractor; and a l2-ft straight (S) blade mounted on a D8H tractor. The dozer blade evaluations compared measured blade performance with soil and other site characteristics and with estimated earth-moving performance rates based on earthmoving methodology that accounts for the traction and speed of the tractor. The earthmoving methodology was also validated with data collected during this program.

Jan 1, 1978