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By William R. Sharp

This Bureau of Mines report details a technique for aiding the engineer with the long-range design of an underground mine. The method is based upon the assumption that sufficient data are available to assign numeric values to some finite number of mineralized blocks; assignment of numerical values is problem dependent. By assigning appropriate weighting schemes, the algorithm developed in this report may be used to solve the optimal end-of-life underground mine layout, design least-cost electrical layout networks and efficient material handling networks, find least risk escape routes in the event of an accident, etc. The method is based upon the assumption that sufficient cost and geologic data is available to build a detailed mineral block inventory of the mineral deposit. It is further assumed that the cost assigned to any minable unit is independent of the neighboring blocks. The basic approach relies upon concepts and ideas from the theory of networks. To make the approach user oriented, a computer program is included and discussed. The computer code is written for an orthogonal, three-dimensional set of blocks. Computational costs and experience indicate that the program could be of great benefit in evaluating large complex mineral properties from the viewpoint of predesigning an underground mine layout.

Jan 1, 1974

By J. H. Jansky, P. W. Jeran, G. L. Hassett, M. C. Irani

This Bureau of Mines report tabulates methane emissions from U.S. bituminous coal mines with daily emission rates of at least 100,000 cfd according to States, counties, and coalbeds. Most of the methane emitted is from mines in the Appalachian States. Total daily emissionin 1975 was 216.3 MMcfd, compared with 227.0 MMcfd in 1971 and 214.5 MMcfd in 1973. Thirty counties in nine States had daily methane emissions of 1 MMcfd or more, These emitted 93 percent of the total methane. The highest emissions were from Monongalia County, W. Va,, which accounted for 18.9 percent of the total. This was followed by Marion County, W. Va., 9.6 percent; Buchanan County, Va., 8.5 percent; Jefferson County, Ala., 6.1 percent; and Washington County, Pa., 5.9 percent. The Pittsburgh coalbed emitted 45.7 percent of the total methane, followed by the Pocahontas No. 3 coalbed with 12.9 percent. The report lists 196 mines, of which 60 had daily methane emissions of 1 MMcfd or more. Included in this compilation are the identification and thickness of the coalbed, methane emission, coal production and ventilation rates, number of drifts, shafts, and slopes used for ventilation purposes, shaft depth, age of mine, and gas-to-coal ratio.

Jan 1, 1975

By F. R. Cattoir

This report presents the results of preliminary studies for the evaluation of some fused-salt electrolytes for refining tungsten metal, and describes the equipment used. Some impurities could be eliminated with electrolytes composed of sodium chloride, sodium iodide, or sodium tetraborate in combination with tungstic oxide or sodium tungstate. Electrolytes composed entirely of chlorides were unusable because of the volatility of tungsten chloride. Refining 96-to 98-percent tungsten to produce a commercial grade was more successful than further refining of 99.9-percent tungsten. No electrolyte tested yielded a product pure in all respects. Electrolyte temperatures of about 900° C were necessary to maintain a good dissolution rate at the anode and acceptable cell operation. Cathode current densities at the beginning of a deposition cycle were limited to approximately 1 ampere per square inch. Higher current densities resulted in a finely divided product that frequently failed to adhere to the cathode. The most conspicuous impurities in the tungsten produced were carbon, iron, and molybdenum; the former two came from the iron cell and the graphite cell liner. Electrolytes com-posed of tungstic oxide or sodium tungstate in sodium iodide, or 2Na, 0.B203, were capable of producing tungsten carbide.

Jan 1, 1963

By Robert B. Schluter

The Bureau of Mines investigated separating copper-nickel mattes to recover a copper-rich fraction suitable for processing by conventional copper metallurgical processes and a nickel-rich fraction suitable for processing in a hydrometallurgical nickel circuit. Distribution of cobalt and precious metals between the copper and nickel fractions was also determined. A matte containing a nominal 65 pct Cu, 9 pct Ni, 4 pct Fe, and 20 pct S was separated into a copper fraction that comprised 80 pct of the matte weight and contained 70 pct Cu and <1.5 pct Ni, plus a nickel fraction that contained 40 pct Ni and 30 pct Cu. Recoveries of copper and nickel into their respective fractions were 90 pct and 87 pct. These results were obtained in a laboratory flotation cell at a matte grind of 90 pct minus 500 mesh and a pH of 12.4, using 1.7 pounds DPG (diphenylguanidine) per ton of matte as collector and frother. Magnetic separation was used to remove metallic iron-nickel alloy from the copper fractions. Distribution of cobalt was about 70 pct to the nickel fraction and 30 pct to the copper fraction. Silver reported predominately to the copper fraction, while Au, Pt, and Pd were essentially entirely recovered in the nickel fraction.

Jan 1, 1982

By P. R. Tisot

The structural response of propped oil shale fractures was determined for each of two different grades of Green River oil shales (38.0 and 29.0 gpt) as they were heated in an inert atmosphere from ambient to subretorting temperatures (below those required for rapid pyrolysis of the organic matter). Small oil shale cores were propped apart by 3-mm glass beads to simulate a small cross section of a propped oil shale fracture between an injection and a producing well. These specimens were then heated at a uniform bate up to 800° F in a specially designed test cell under stress levels from 100 to 1,000 psi in biaxial and in triaxial confinement. Under the conditions of heat and compressive stress utilized in this study, all of the propped fractures in the two oil shales underwent structural deformation ranging from partial to complete collapse, as evidenced by proppant embedment. Structural collapse of induced fractures would in turn result in serious impairment or complete loss of the fracture flow capacities of the specimens. Results from this Bureau of Mines study indicate that underground retorting of Green River oil shale may be seriously impaired by loss of permeability when utilizing propped fractures in oil shales assaying more than 28 gpt.

Jan 1, 1975

By Donald P. Blasko

The Bureau of Mines investigated two areas of oil and gas seeps in the north-central Gulf of Alaska--Katalla River to Bering River and Cape Yakataga to Yakutat Bay to determine (1) whether previously reported seeps are still active, (2) the characteristics of the seeping hydrocarbons, and (3) the amount of bitumen contained in the drainage leaving the seeps and entering the Gulf of Alaska. Thirteen separate oil seeps, six bitumen deposits, and eight gas seeps were located, sampled, and analyzed. The oils ranged from 35.2° to 14.1° API gravity and had sulfur contents from 0.53 to 1.31 wt-pct. Bitumen samples had API gravities from 2.4° to 14.6° and sulfur contents from 0.28 to 0.88 wt-pct. Gas samples had specific gravities ranging from 0.577 to 0.883 and caloric values from 724 to 1,427 Btu/cu ft. A total of 63 water samples obtained from seep locations and seep drainages were analyzed by atomic absorption spectrophotometry for ionic content and by solvent extraction for hydrocarbon content. Although some of the water at the oil seeps had a bitumen content as high as 246,000 mg/1, the amount of hydrocarbons actually reaching the Gulf of Alaska averaged <0.2 mg/1.

Jan 1, 1976

By Carla A. Kertis

Because coalbed discontinuities often pose serious economic and safety problems in underground coal mines, criteria were documented for the recognition and prediction of discontinuities in advance of mining. Pennsylvanian strata in Indiana and Armstrong Counties, PA, were deposited as part of fluvio-deltaic complexes with channel-phase sandstones as the predominant type of coalbed discontinuity. Coalbed isopach maps constructed for this study delineated numerous want areas (areas of no coal) with elongate to linear geometries. A comparison of coalbed isopach and corresponding sandstone isolith maps of the study area revealed many examples of a thick-sandstone, thin-subjacent-coalbed relationship. Nearly 60 pct of the want areas in the study area were found to lie subjacent to thick (> 20 ft [6 m]) sandstone accumulations. In addition to erosion of the coalbed, channels may contribute to coalbed splitting, coalbed thinning over paleotopographic highs, abnormal coalbed thick- nesses, and deterioration of coal quality. If these features are considered, then approximately 80 pct of all interruptions in the economic coalbeds in this area result from channel activity. By using the criteria developed in this study and described in this Bureau of Mines report, the occurrence of coalbed discontinuities may be predicted and anticipated in advance of mining.

Jan 1, 1985

Spectrochemical methods were developed to determine beryllium in the concentration range 0.0015 to 4.0 percent in siliceous mineral beneficiation products. Two methods are described. They are (1) a fusion-pellet-spark procedure (spark method) and (2) a sustaining alternating-current arc procedure (arc method). In the spark method the sample is fused with lithium tetra-borate and vanadium pentoxide. The resulting bead is crushed, mixed with powdered graphite, and briquetted. This is analyzed spectrographically using controlled high-voltage spark excitation. In the arc method the sample is diluted with germanium metal, graphite, and vanadium pentoxide. Weighed charges are packed into cupped graphite electrodes and subjected to excitation with a sustaining alternating-current arc. Vanadium serves as internal standard for both methods. Effects due to matrix variations in samples and standards are eliminated either by fusion with lithium tetraborate in the spark method or by dilution with germanium and graphite in the arc method. Beryllium determinations show deviations from accepted chemical values of approximately 5 and 8 percent for the spark and arc methods, respectively. Analyses can be made more rapidly by the arc procedure with a sacrifice in precision and accuracy. Either method can be applied to the determination of beryllium in silicate rocks.

Jan 1, 1962

By K. L. Williams

The Bureau of Mines tested a prototype tapered-element oscillating microbalance (TEOM) dust monitor for measuring respirable coal mine dust. The monitor uses the inertial behavior of a vibrating element to measure the mass of sampled dust. Tests were performed to determine variability, drift, the effect of humidity, placement of collection filter, and element orientation during analysis, and comparability with gravimetric measurements of respirable coal dust. Variability was about 1.6 µg. Over about 26 h at 46 pct relative humidity, drift was very slightly negative. When the relative humidity was increased to 78 pct, all units showed a total positive change less then 40 µg over about 70h. Filter placement variation on the tapered element resulting from in- consistent sizing of the filter mounting bases caused significant error (up to 0.2 mg). In practice, calibration of the system for each new filter will eliminate that error. Orientation of the element during analysis did not introduce significant error, but care is necessary when mounting the canister that houses the element to avoid damping oscillation of the element. Dust tests were performed in an aerosol chamber using coal dust. Measurements made by the TEOM dust monitor agreed to within 10 pct of simultaneous measurements by gravimetric personal samplers.

Jan 1, 1986

By Thomas H. Dubaniewicz

Fiber optic systems are being deployed in locations where explosive gas atmospheres are normally present or are present under fault conditions. The National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory (NIOSH, PRL) conducted a study of laser safety in potentially flammable environments. Researchers conducted experiments to estimate the mean and standard deviation of laser powers needed to ignite 6% methane-air atmospheres using single mode optical fiber tips covered by two types of iron oxide (Fe304 and (FeMn)203) mixed with a ceramic adhesive. The iron oxides, heated by a 1064 nm continuous wave laser, ignited the methane-air mixtures ,at similar powers. The minimum igniting power and maximum non-igniting power (10 tests) were 407 and 350 mW, respectively, using a 62.5 pm fiber. Laser beams guided by 125 and 80 pm diameter cladding single mode fibers produced similar methane-air igniting powers. Ignition was not observed using coal particles at powers that produced ignition with the iron oxides. Threshold ignition delays using the single mode fiber were approxinlately proportional to the inverse square of the igniting power. Ignition delays were significantly longer than the reported activation time for a comnlercial fiber optic power limiter. Comparisons are made with the results of other researchers. Published by Elsevier Ltd.

By Claude A. Tongish

This Federal Bureau of Mines report presents information on the accumulation and distribution of helium in U.S. natural gas reservoirs. The investigation concerns the relationship or association of helium with geographic location, geologic age, reservoir depth, nitrogen, carbon dioxide, and argon. Although helium is a minor constituent in natural gas, these data show that certain conditions make some reservoirs statistically more favorable than others for the accumulation of helium. The report is based on gas analysis information collected-by the Bureau from 1917 to 1974 from 10,086 gas samples, representing 6,455 reservoirs in 35 States. The occurrence of helium in the reservoirs was 11.5 percent with less than 0.005 percent of helium, 70.9 percent with 0.005 through 0.29 per-cent of helium, and 17.6 percent with 0.30 percent or more of helium in the gas. Results of the various correlations are presented in tables and charts. Relationships have also been determined quantitatively by measures of correlation. The statistical data can be used to determine the environment under which reservoirs with high-helium contents are most likely to occur. These data can be used with other information for predicting the future helium resources of the United States.

Jan 1, 1980

By M. Hertzberg

This Bureau of Mines report describes experimental and theoretical studies of diffusion flames in free convection. The cross-coupling between buoyancy-induced flows and the combustion process is explored as it relates to the size, structure, and radiative balance of flames. New data are presented for the size-dependent radiance oscillations of diffusion flames and for the angular distribution of the total radiant intensity from a small methanol pool flame. Both amplitude and frequency of the measured oscillations are compared with theoretical predictions that are based on a new view of the structure of diffusion flames. This new view, which is at variance with the traditional one, assumes uniform reaction in the diffusive mixing zone, and recognizes the significance of the role played by convective buoyancy and its duality in both aiding and impeding flame propagation. Buoyancy quenches propagation at low burning velocities, introducing a real discontinuity in the combustion rate. A "flammable volume" is thus defined as that bound between lean- and rich-limit contours. However, in the flow disturbances generated by combustion waves that consume that volume, buoyancy aids propagation by promoting the convective mixing of a new flammable volume. The measured radiance oscillations are manifestations of these propagation and remixing cycles.

Jan 1, 1978

By Otto Robert Stein

Erodibility of reclaimed surface mine soils is a subject in need of quantification. Effects of soil erosion from reclaimed areas may damage surrounding areas and the quality of water in nearby streams and lakes. It may also reduce the potential productivity of the reclaimed site. A study was conducted to determine erodibilities of different reclamation treatments and a nearby unmined soil at three Indiana strip mine sites. A rainfall simulator was used to artifically erode plots con¬structed within seven treatment categories and the unmined soil. Soil erodibility was assessed in terms of the Universal Soil Loss Equation (USLE) K factor. Values for K calculated from field data were compared to values predicted from independently measured soil properties. Differences in soil erodibility between treatments were site specific. Unmined soil had the highest calculated erodibility at one site but at two other sites soils having reclaimed A horizons were highest. Shaley overburden treatments had the lowest calculated erodi¬bility. Predicted soil erodibility was usually lower than that calcu¬lated from field data. Site specific slope gradient factors (S) were developed for reclaimed A horizon treabnents. This was done because the USLE S factor overestimated the measured soil loss at steeper slopes.

Jan 1, 1983

By Lloyd A. Morley

Research performed on computer modeling of mine power systems under USBM Grant G0155003 1S described. The work was performed at the Pennsylvania State University from 5 November 1975 through 4 November 1976. Results presented are interim in nature, and future research is planned to integrate the simulations which have been developed. The thrust of this research has been divided into three main areas. 1. Modification of a previously developed model (Mine Power System Simulation or MPSS) to include interactive operation and the use of default (average) load data. 2. Development of a dynamic simulation of interdependent mine power system induction motors. 3. Development of an approach to modeling of motor shaft loading of induction machines for mining operations. During the course of the current year&apos;s research, significant results have been achieved in all areas. Construction of an interactive MPSS model has been completed and checked. This simulation was written in APL code and is fully interactive. In addition, default data representing 158 different pieces of mining equipment has been developed for use with the interactive model. Additional work described includes the construction of a dynamic simulation of interdependent continuous miner induction motors and the development of an approach fo: motor shaft load torque computation from experimental data.

Jan 1, 1976

By Richard H. Bares

The general or macroclimate of the study sites in western North Dakota is characterized by rapid and sometimes extreme daily and day-to-day temperature fluctuations, rainfall patterns which are erratic in spatial and temporal distribution and intensity, generally low relative humidity, plentiful sunshine, nearly continuous air movement, and a relatively short frost-free period. Of particular relevance to plant growth and productivity is the mosaic of microclimates: these microclimates are affected by landform (convex and concave surfaces); exposure; slope angle, length and aspect; soil color, texture and surface cover (litter), and vegetation cover. The most critical plant growth governing factor in this region is available water. It is determined principally by water input (precipitation) and water loss (evapotranspiration) which is increased by high temperatures, wind, and poor litter and vegetation cover. While spring and fall precipitation is generally gentle and soil-soaking summer rains frequently come in the form of intensive, soil-washing, localized convective thunderstorms of short duration. Due to the convective nature of these storms, summer rainfall is particularly affected by regional topography; southwest slopes and crests often receive more rainfall since these storms usually move in a northeasterly direction. The water loss due to runoff and consequent soil erosion arc major problems resulting from such "cloudbursts". Previous fall precipitation (September - October) when added to current seasonal precipitation (March - August) was found to be significantly correlated (r-.93) with plant production. Winter precipitation (snowfall) is relatively light as the prevailing weather is dominated by dry polar air masses from the north. The nearly continuous wind is responsible for removing snow from open exposures and depositing it in depressions and windbreaks. Although the winter precipitation is not a large component of the total annual precipitation, conservation of that which does occur would contribute to plant production during the following growing season. Generally clear skies over the region facilitate receipt of abundant sunshine at the earth&apos;s surface. While good for early season soil warming and plant photosynthesis, this abundant sunshine coupled with long days and nearly continuous wind is responsible for evapotranspiration exceeding precipitation by an average of six inches between June&apos; and September. On a local (micro) scale, the water deficit is most severe on the southern exposures which receive the most direct (most effective) solar radiation and therefore are warmer than other exposures. On a broader scale, it was found that ambient temperature extremes were slightly but significantly greater in the town of Beulah in the Knife River Valley than at the upland test sites, This may have been due to the difference in topography and/or the "urban heat island" effect. It is known that air temperatures in large cities may be 2° to 4°C higher than that of the surrounding countryside. It is also well known that basins, depressions or valleys are sinks for cold air masses and are often subject to frosts not occurring on adjacent upland sites.

Jan 1, 1982

By Mark L. Chatman

This report presents an economic mineral assessment and Inventory of mines and prospects In the approximately 176,000-acre Patagonia Mountains-Canelo Hills Unit of Coronado National Forest. Deposits or areas most likely to experience future development are characterized in terms of their economics, based on data acquired by the author from a variety of sources, and supplemented by USBM field data collected by other workers in 1990 and 1991. Numerous mine maps, rock-chip sample assays, and detailed descriptions of mine and prospect sites are in this report and appendixes. Heavy but sporadic mining, mainly between the 1850&apos;s and 1950&apos;s was nearly all confined to the Patagonia Mountains. High-grade sulfide veins, replacements, and skarn deposits accounted for most of the production, which included large quantities of zinc, lead, copper, and silver, and considerable quantities of gold. Small Quantities of molybdenum, manganese, tungsten, and placer gold have been mined. Most of the traditionally mined metalliferous sites will not see future activity due to the low tonnages present and removal of most high-grade rock. Possible future development areas include copper porphyries and breccia pipes; most are too deeply buried for current development. Localities where similar deposits may be concealed are identified.

Jan 1, 1994

By C. M. McKinney

This report presents analyses of crude oil from most of the fields in the United States producing 2,500 barrels per day or more. The purpose of the report is threefold : 1) To present detailed analyses of crude-oil samples from as many al possible of the important fields in the United States. On January 1, 1947, there were 340 fields producing 2,500 barrels & day or more. Analyses for 283 of these fie1ds are presented. Fifty-seven fields have been omitted because the Bureau of Mines did not have analyses or the crude oils being produced. As one sample was not representative of the promotion from several of the fields, two analyses are given for each field of this kind. (2) To compile these analyses, many of which have not been published previously in a single report. Since the publication of Bulletin 291 in 1928, there has been no report showing analyses of crude petroleum from fields throughout the United states, but a number of separate reports according to area or state have been issued. Many of these are out of print. (3) To provide a means of ready comparison of the properties of crude oils from different areas of the United states.

Jan 1, 1948

By Todd M. Ruff

Blind areas around construction equipment are a major contributing factor in incidents involving a piece of equipment striking a worker. In highway construction, these types of incidents result in an average of 22 deaths a year in the United States. The Spokane Research Laboratory of the National Institute for Occupational Safety and Health, in cooperation with the Washington State Department of Transportation, is evaluating methods to decrease these incidents. One such method uses devices that assist equipment operators in monitoring blind areas around the equipment to prevent collisions with workers or other objects. Several camera and sensor systems are available for this application. These systems were evaluated on various trucks used in road construction and maintenance. Tests were conducted on sanding trucks during the winter months, which allowed researchers to investigate the effectiveness and limitations of various technologies under the most extreme conditions. Tests were also conducted on dump trucks and utility vehicles during the warmer months to study the effectiveness of the systems in highway work zones. Results showed that many difficulties arise when using camera and sensor systems in cold, snowy climates. And, while the operation of these systems is more reliable during the warmer months, challenges still exist in using them on equipment in congested work areas.

By E. Chin

The countries of Asia and the Pacific have large resources of diverse minerals. Australia and China have extensive mineralization that are commercially being exploited. The major minerals in Australia with known reserves adequate for both domestic demand and export markets include bauxite, clays, copper, diamond, gold, iron ore, lead, manganese, mineral sands (titanium minerals), nickel, salt, silver, tin, uranium, and zinc. China is the world leader in proven reserves of antimony, barite, magnesite, molybdenum, rare earths, titanium (ilmenite), tungsten, and vanadium. It also has about 55 billion tons of iron ore, albeit with an average grade of only 30 % to 35 % elemental iron content. With the exception of chromium and copper, China has significant resources of a wide array of minerals and metals, based on its production and/or export capability for these commodities. Additionally, India has significant resources of bauxite and mineral sands; Indonesia, bauxite, copper, nickel, and tin; Malaysia, tin and associated titanium; Mongolia, copper, fluorspar, and lead-zinc; New Caledonia, nickel; New Zealand, gold and iron sand; North Korea, magnesite; Papua New Guinea, copper, gold and mineral sands; Philippines, copper, chromite, and gold; and Sri Lanka, gemstones. Moreover, there appears to be extensive mineralization III Burma (Myanmar), Cambodia, Laos, Thailand, and Vietnam, but they have yet to be definitively delineated.

Jan 1, 1994

By O. C. Blade

"An important function of the Bureau of Mines is promoting the conservation and more efficient utilization of a natural resource. Petroleum is such a resource, and its utilization depends to a considerable degree upon its characteristics. For this reason the Bureau of Mines, over a period of years, has analyzed many samples of crude petroleum by the Bureau of Mines Hempel method 3/ and published complications of crude-oil analyses. Among such publi¬cations are several reports presenting analyses of crude oils from fields in Oklahoma. The most recent of these relates to samples from southern Oklahoma. 4/ The present paper provides additional analyses of Oklahoma crude oils, largely from areas and formations not heretofore represented in published reports. The analyses of 248 samples from 153 fields are presented individually and collectively in the tables of this report.Crude oil has been produced in Oklahoma in commercial quantities since 1891, and peak production was reached in 1947. The State's cumulative production to January 1, 1944, is, according to the American institute of Mining and Metallurgical Engineers, 5,186,466,000 barrels. 5/ The annual production of crude petroleum in Oklahoma for each year from 1891 to 1943, inclusive, is given in table 1."

May 1, 1945