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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

By J. Sammarco

The U.S. National Institute for Occupational Safety and Health (NIOSH) is conducting mine illumination research to determine if light-emitting diode (LED) cap lamps can improve safety by reducing glare. Glare can impede a miner?s ability to see hazards and to safely perform their work. Another objective is to determine if a person?s age is a factor. This is important because the workforce is aging ? the average miner is now about 43 years old. Three cap lamps were used to evaluate glare: an incandescent cap lamp, a commercially available LED cap lamp and a NIOSH prototype LED cap lamp. Thirty NIOSH personnel from the Pittsburgh Research Laboratory (PRL) served as test subjects. Three age groups were established with ten subjects in each group. Testing was conducted in the Mine Illumination Laboratory (MIL) of NIOSH PRL. The results indicate no statistically significant difference in discomfort glare among the incandescent and LED cap lamps. However, an analysis of variance for disability glare indicates that the LED cap lamps were superior for the older subjects. Disability glare scores for the oldest subject group improved 53.8% when using the NIOSH prototype LED cap lamp compared to the incandescent cap lamp and 36.5% compared to the commercial LED cap lamp. It ap­pears that, given the conditions of this study, LED cap lamps will not increase discomfort glare and can enable significant improvements in disability glare for older workers. It is also evident that not all LEDs are created equal. The disability glare improved the best for older workers when they used the NIOSH prototype LED cap lamp, which has a different spectral power distribution (SPD) (more short wavelength energy) than the commercial LED cap lamp. Therefore, for disability glare, the results suggest that the SPD is an important factor to consider in cap lamp design.

Jan 1, 2009

By W. T. Wertman

A research program to aid development of better and more efficient methods for producing petroleum and increasing its ultimate recovery from underground formations is an integral part of the work of the Bureau of Mines on conservation of the Nation's natural resources. Economic, efficient production of recoverable oil and gas from a reservoir depends to a great extent upon the best and most accurate information that can be obtained from a study of the reservoir rock and its fluid contents. Information on oil and water saturation is pertinent and essential in wildcat, extension, and pool wells for good reservoir operations and prediction of performance. This report presents results of an investigation by the Bureau of Mines of core recovery and degree of drilling-fluid contamination occurring during cable-tool coring operations using oil-base mud. Representative core samples were obtained from 6 major oil-producing sands in 8 fields of West Virginia, Pennsylvania, and New York. Field-mixed, oil-base drilling mud was used for the first coring test, and lightweight, premixed oil-base mud, with an organic chloride tracer added, was used in coring eight other wells. Tracer analyses were made to determine contamination of core by drilling-fluid filtrate. Core analyses, including oil and water content and minimum interstitial water-saturation tests, were made on selected core samples to compare and evaluate water saturations determined by the two methods.

Jan 1, 1958

This report presents the results of a study of Kennecott Copper Corporation?s Chino leaching dump at Santa Rita, N. Mex. The stability studies described herein were performed on only one cross section of the leach dump, utilizing data obtained from drilling, sampling, and testing, which was limited in nature. The first part of the report contains a discussion of site geology and seismicity, pertinent information on the waste material disposal system and leaching method, a discussion of the waste embankment characteristics, a summary of the engineering analyses, and a bibliography. The second part (appendices) contains basic geologic and engineering data supporting the discussions in the first part.

Jan 1, 1974

By Forrest T. Moyer

The safety record of the coal-mining industry in 1968 worsened appreciably .in fatality experience but was slightly better in nonfatal-injury experience. Work fatalities in 1968 totaled 311 and occurred at a frequency rate of 1.33 per million man-hours or worktime. The fatality total was 89 higher, and the rate of occurrence was 45 percent higher than the corresponding figures of 222 fatal injuries with a frequency rate of 0.92 in 1967. The worsened fatality record in 1968 resulted primarily from two major disasters (a single accident which results in the death of five men or more) which killed 87 men, nine in one and 78 in the second. The total of 9,639 nonfatal injuries was the lowest annual figure in complete records back to 1930. The frequency rate of 41.12 nonfatal injuries per million man-hours of worktime for 1968 was the second lowest annual rate of occurrence. The severity rate of all injuries, 10,513 days lost or charged per million man-hours, and the average severity, 248 days lost per injury, in 1968 were the worst annual data in the series started in 1944. Total worktime of 234.4 million man-hours and coal output of 553.3 million tons in 1968 were, respectively, 3 and 1 per- cent lower than in 1967.

Jan 1, 1972

By Clarence Karr

THE BUREAU OF MINES is investigating methods for upgrading tar produced by the low-temperature carbonization of bituminous coal. This survey was undertaken to compile information needed for identifying the ether constituents of low-temperature tar. Physical properties are listed for 1,024 aromatic ethers. The compounds include cyclic and noncyclic, polyfunctional and monofunctional ethers with oxygen joined directly to either one or two aromatic rings. Alkyl groups up through butyl are included. The compounds are divided into 37 groups ranging in complexity from alkoxybenzenes to dibenzopyrans. Compounds containing aromatic ether groups are important constituents of the neutral oxygen components of low-temperature tar. For example, at Morgantown, W. Va., the Bureau of Mines has identified and determined the amounts of benzofuran, 2-, 3-, 5-, 6-, and 7 -methylbenzofuran, diphenyl ether, dibenzofuran, 2,3-dimethyldibenzofuran, and two other dimethyl-dibenzofurans in the neutral oil from a low-temperature bituminous coal tar (103, 104).3

Jan 1, 1962

By Steve C. Albrecht

The objective of this study is "to assess the impact of surface mining on soil compaction in the Midwest". The study revolves around a unique field sampling program targeted at four mine sites utilizing four distinct types of soil movement of midwestern prime land. Through the preparation of a final report for use as a guidebook, an assessment is made of the degree to which surface mining operations contribute to the soil compaction problem. The final report is formulated through the use of field study data as well as information gathered in an intense literature review. The final report centers on applying collected data to practical field applications. Soil sampling on the four mine sites centers on a comparison of natural and replaced soils for moist bulk density. This characterization evaluates changes in density and texture throughout the soil profile to a depth of 48 inches. Fertility of the topsoil is also assessed for natural and replaced soils. During field sampling and observations, a base of information has been gathered to compile a case study on each mine site. The report accesses the regulations in the prime farmland areas through the use of a matrix. The regulatory matrix allows easy access of mining personnel to State and Federal regulations.

Jan 1, 1982

By M. W. Von Bernewitz

Fay's glossary3/ of terms contains the following definition of "black sand": Heavy grains of various minerals which have a dark color and. are usually found accompanying gold in alluvial deposits, for example, magnetite, chromite, ilmenite, cassiterite, tourmaline, and others. The Bureau of Mines is issuing this report in answer to the many inquiries from individuals and firms as to how they may treat or sell the heavy black sands that accumulate in the sluice boxes of beach and river placering and to warn such individuals and firms against becoming too enthusiastic over the chances of striking it rich. For a half century or longer much money, energy, and time have been wasted in devising, building, and trying numerous machines to recover gold and platinum, also gem stones, from sand that generally has not been worth the effort. Volumes have been written on the subject, and thousands of letters of inquiry have been received by agencies of the State and Federal Governments. The demand for information has been so great that all of the Bureau's publications dealing wholly or partly with black sands are out of print. They are listed at the end of this report.

Jan 1, 1938

By Annie G. Smelley

The Bureau of Mines is testing a dewatering technique for phosphatic clay waste that will recover a portion of the water lost using conventional waste disposal methods and produce solids suitable for land reclamation. The technique utilizes a flocculant, polyethylene oxide (PEO), that forms strong, stable flocs that can be dewatered on a static screen followed by further dewatering on a rotary screen. In field tests conducted in northern Florida, clay wastes containing a nominal 2.5 pct solids have been consolidated to greater than 20 pct solids. The rate at which PEO-treated material continues to dewater in a mine cut also was monitored. Preliminary results indicate that PEO--treated material will dewater to 30 pct solids in 140 days. Pretreatment of phosphatic clay waste with lime and H202 was shown to improve the dewatering technique for problem clay wastes.

Jan 1, 1985

By Philip W. Holland

This Bureau of Mines report discusses the results of three independent reconnaissance geochemical surveys conducted in the vicinity of the Bush Dome reservoir in the Bureau-owned Cliffside field near Amarillo, Tex. The surveys consisted of (1) determining the helium content of area ground waters, (2) determining the helium content of area soil gases and ground waters, and (3) determining the helium content of soil gases collected on a grid sampling pat- tern in the Cliffside field area. The native natural gas in the Cliffside field contains about 1.8 percent helium. To date, approximately 54 billion cubic feet of gas containing approximately 39 billion cubic feet of helium has been injected into the center of the Bush Dome structure. The research work, which was completed under contracts, was done to determine if helium concentration levels in ground water and soil gas could he used as an indication of the presence of helium in a subsurface natural gas accumulation. Results of the surveys were positive in that helium-in-water and helium-in- soil-gas anomalies were detected in portions of the Cliffside field area. All helium analyses were performed by mass spectrometric techniques.

Jan 1, 1979

By A. G. Mayton

Vehicle vibration exposure has been linked to chronic back pain and low back symptoms among agricultural tractor drivers. The objectives of this study by the National Institute for Occupational Safety and Health (NIOSH) were to assess driver whole body vibration (WBV) exposures and recommend interventions to reduce the risk of back related injuries, particularly relative to vehicle jarring/jolting (the transient mechanical shock components of WBV). The methodology included collecting, from two independent samples, ?eld data and health and work history data of farm equipment operators. Data were collected during mowing, raking, baling, chiseling, tilling, and road travel for different model tractors. Spraying using a sprayer and shrub removal with a skid steer loader were also included. Based on ISO 2631 (1985), the American Conference of Governmental Industrial Hygienists, threshold limit values, presents 0.5 m/s2 as the action level recommended by the Commission of European Communities for overall weighted total RMS acceleration (vector sum for axes x, y, and z) [ACGIH, 2006. Threshold limit values and biological exposure indices. Cincinnati, OH]. WBV measured at the operator/seat interface exceeded this action level. The roughest rides and highest vector sum accelerations occurred with small utility tractor mowers (3.3 and 2.8 m/s2) and a skid steer loader (1.7 m/s2). Major ?ndings from health and work history data showed 96% of participants reported having to bend or twist their necks, although 24% reported neck symptoms. Sixty four percent of participating operators reported experiencing back symptoms (e.g., pain, aching, stiffness, etc.). Recommendations included: specifying a seat that ??better?? isolates operators from jars/jolts with new tractor purchases; maintaining the seat/seat suspension and replacing worn or damaged cushions with NIOSH tested viscoelastic foam padding; using larger diameter tires with radial ply instead of bias ply construction, particularly on small utility tractor mowers, to aid in attenuating ride ??roughness??; using a swivel seat to reduce the stress on the neck from bending or twisting; and improving efforts to educate owner/operators of the adverse effects of WBV exposures. Since the data presented in this paper were collected from two independent samples, the authors were unable to draw any correlations or etiological inferences from the study. However, results were compared and contrasted with other studies which included similar vibration measurements in agriculture.

Jan 1, 2008

By Frank B. Fulkerson

Aluminum production in the Pacific Northwest has a new potential for expansion and increased stability of operation. This new potential results from greater availability of power; lower freight rates on alumina and aluminum; good market prospects for the metal, including western aluminum market expansion following a decline in defense requirements in the 1950's; and possibility of developing bauxite deposits in the Pacific Basin as well as other mineral resources. INTRODUCTION This is a report of a special study by the Bureau of Mines of the primary aluminum industry of the Pacific Northwest. It outlines developments relative to the United States as a whole.

Jan 1, 1962

By J. R. Nettle

The purpose of these studies by the Federal Bureau of Mines was to determine the feasibility of refining low-grade hafnium by an inert-gas-shielded molten-salt electrorefining technique to produce a hafnium metal meeting reactor specifications. The techniques were adapted from those used success-fully for titanium electrorefining. Three electrolytes containing hafnium chlorides were developed from which deposits having a Brinell hardness of 170 or below were recovered. A KC1 + NaC1 + HfC14 electrolyte produced deposits in the hardness range of 140 to 165 Brinell. Deposits with a hardness range of from 132 to 152 Brinell were pro-duced from an electrolyte composed of KC1 + LiC1 + HfC14. A third electrolyte composed of NaC1 + K3HfC17 produced deposits with a hardness as low as 139 Brinell. In a fourth electrolyte, composed of NaC1 + K2HfF6, a measure of refining was accomplished, but under the test conditions no metal meeting specifications was recovered; none was softer than 174 Brinell. A number of metallic impurities were reduced in quantity by the electro-refining process, notably iron, which normally was reduced from 250 p.p.m. to less than 50 p.p.m. Magnesium generally was reduced from 680 p.p.m. to less than 80 p.p.m. Manganese content was also reduced by the electrorefining process. Sponge containing 90 p.p.m. Mn yielded deposits containing a maximum of 50 p.p.m.; some deposits contained only 10 p.p.m.

Jan 1, 1961

By Choon Kooi Quan

Water availability is essential for mining and minerals processing. To provide government and industry with recent data for water use planning and management, the Bureau of Mines canvassed a number of U.S. producers of nonfuel minerals to determine their water use in 1984. Data were analyzed and compared with previously published data in order to examine historical trends in water utilization in the nonfuel minerals industry and to estimate water requirements in the year 2000. Total water use in the domestic nonfuel minerals industry during 1984 was estimated at 2,267 billion gal, of which 571 billion gal was new water and 1,696 billion gal recirculated water. The largest users of water were the phosphate rock, iron ore, copper, sand and gravel, and crushed stone industries, together accounting for almost 90% of total used. More than one-half of all water was used in Florida, Michigan, and Minnesota. In the year 2000, total water use will amount to an estimated 2,679 billion gal, of which 810 billion gal will be new water and 1,869 billion gal recirculated water. Most of this water would be used in producing the foregoing suite of minerals,

Jan 1, 1988

By Louis A. Panek

An improved centrifugal-testing apparatus has been designed and built in the Bureau of Mines laboratory at College Park, Md., which is unique in that it incorporates the use of resistance gages to measure directly the strains in a rotating model without testing it to failure. Owing to this feature, a more rapid testing method can be used; furthermore, model materials need not be restricted to those of the prototype. The behavior of any structure in which strains of significant magnitude are produced by its own weight may be studied in a small model subjected to simulated gravity loading. The model is rotated in a centrifuge to induce in it centrifugal forces, which, like the gravitational forces in the full-size structure, act on the volume elements and are proportional to the masses thereof. Centrifugal testing is, therefore, applicable to the design of mine openings and to the study of similar ground-control problems. It constitutes an experimental method for determining the state of strain in a structure for which analytical methods are excessively laborious or even impossible. In previous applications of centrifugal testing by other investigators, the models usually were tested to failure, and the analysis was made from-the type of break produced. The models were made of the same materials as the proto-type, and the test results were applied only to the particular prototype represented by the model. Beam deflections were measured from photographs of the rotating model, but no means was employed either to determine the actual distribution of stress in the model or to determine quantitatively the degree of restraint imposed on the ends of the loaded model beam, that is, to determine whether the loaded model behaved as a beam with rigidly fixed ends or as some other type of beam. With the apparatus described, it is possible to determine the state of strain, and thus the boundary conditions, in a rotating test model weighing up to 90 lb., which can be subjected to centrifugal forces up to about 2,600 times the force of gravity. The load-strain relationship, applicable directly to the prototype, can be determined from a Single model test. The test results can be presented as quantitative relations between the loads, strains, and dimensions and mechanical proper-ties of the structural members and can be applied to any prototype, whatever its component materials, that satisfies the similarity requirements.

Jan 1, 1952

By W. N. Hoskins

This report covers the final results of a two-phase contract study conducted between July 1974 and October 1976. A comprehensive summary of the initial phase of the study is included. Phase I of the study involved the investigation and evaluation of all potential candidate underground systems for mining the deeper deposits of oil shale and associated minerals in the Piceance Creek basin of northwestern Colorado. Phase II called for the refinement and the detailed technical and economic analysis of the most promising system, or systems, thus disclosed. Of the several systems initially investigated and evaluated, four showed considerable merit for exploiting the deeper deposits: (1) chamber and pillar mining with spent shale backfill, (2) sublevel stoping with spent shale backfill, (3) sublevel stoping with full subsidence, and (4) block caving mining using LHD's. Final refinement and analysis of these four systems indicated their technical feasibility over at least part of the range of conditions expected in the deeper deposits. Their economic feasibility also was indicated under certain operating and market conditions. A variety of engineering, production, and cost information is provided on each of these systems.

Jan 1, 1976

By D. H. Desy

The Bureau of Mines has conducted research on the ignition of methane-air mixtures by sparks caused by frictional impact of aluminum alloys on rusted steel at typical coal mine fan speeds. The objectives were to establish the incendivity of aluminum alloys under these conditions, to investigate differences between aluminum alloys, and to evaluate substitute materials for the aluminum-steel combination. With a specially designed apparatus, three commercial aluminum casting alloys and a number of experimental aluminum alloys were tested for incendivity of the frictional impact against rusted steel in flammable methane-air mixtures. All aluminum alloys tested produced some ignitions. Of the experimental alloys, the harder alloys and those containing silicon tended to be more incendive than the others. With the normal experimental conditions, constructional steel, stainless steel, brass, and plastic did not cause ignition of methane-air mixtures in frictional impact against rusted steel. Some ignitions occurred with constructional steel at high speed in more flammable gas mixtures enriched with oxygen. From these findings, it is suggested that constructional material combinations other than the aluminum-steel combustion would minimize this inc endive hazard. A detailed description is given of previous research, and comparison is made with present results where appropriate.

Jan 1, 1975

By W. L. Dare

This report is one of a series published by the Federal Bureau of Mines to describe methods and costs of mining uranium on the Colorado Plateau. The Navajo Uranium Division of Kerr-McGee Oil Industries, Inc., mines uranium from several deposits of carnotite-type ores, which lie buried in the Lukachukai Mountains on the Navajo Indian Reservation, Apache County, Ariz. The country is rugged and isolated Constructing and maintaining roads has been a continuous task. The ore bodies occur within the Salt Wash member of the Jurassic Morrison formation and are similar to other such deposits on the plateau. The current mining activity in the Lukachukai Mountains is a result of uranium-ore discoveries in 1949, although the Navajos undoubtedly knew of the outcrops of yellow uranium minerals long before that time. The ruggedness of the country and the heavy soil cover over much of the surface hampered prospecting, but probably the main reason the ore was not found sooner is that no one took the trouble to look for it in the Lukachukai Mountains.

Jan 1, 1961

By R. S. Warfield

Several reconnaissance-type surface and drill core samples of Arctic Northwestern Alaska coals were taken during the summer field seasons of 1964 and 1966 for coking studies. Surface samples were taken from the Kokolik River and the Cape Beaufort areas; core samples were obtained from the Kukpowruk River and the Cape Beaufort areas. Only one Kokolik River surface sample possessed coking properties. This sample, representing an 11.6-ft coal seam, made coke approaching metallurgical quality when a 30-pct portion of selected blending coals was added. Four Kukpowruk River core samples, each representing the same 19-to 20-ft coal seam, were all of about the same coking quality. No differences of coke quality attributable to depth of permanently frozen overburden were found, but the data confirm previously reported information that the 19- to 20-ft coal bed is a potentially satisfactory base coking coal. In the Cape Beaufort area, a core sample with appreciable coking properties was taken at depth from a coalbed determined noncoking in a surface sample.

Jan 1, 1969

By V. R. Miller

The Bureau of Mines developed and evaluated a detecting and sorting device to separate the copper-bearing portion from the barren portion of Michigan native copper ore in the minus 4- plus 1-inch size range. Small-scale sorting tests were also conducted on minus 1- plus 1/2-inch material from the Centennial No. 6 mine, using a previously developed system that was modified to increase sensitivity. Results showed that, with the added sensitivity, 85 to 90 pct of the copper in the minus 1- plus 1/2-inch material could be recovered in about 50 to 60 pct of the fraction. Sorting tests on minus 4- plus 2-inch and minus 2- plus 1-inch fractions from the Centennial mine were conducted with the large sorting system. Results showed that 86 to 93 pct of the copper was recovered in 43 to 64 wt-pct of the sorted fractions. Combining of concentrates from the two fractions resulted in a recovery of 90 pct of the Popper in 55 pct of the weight. The composite concentrate contained 2.40 pct copper, and the tailing analyzed 0.33 pct Cu; the head sample assayed 1.46 pct Cu.

Jan 1, 1978