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By J. J. Taber

Gas and water permeabilities of a large number of samples from the Pittsburgh and Pocahontas coals were measured at various overburden and mean flow pressures. A wide variation in the air and water permeabilities was obtained for each type of coal. Overburden pressure has the most significant effect on the single-phase permeability. Considerable hysteretic effect was observed for both air and water permeabilities. Gas permeabilities are affected to a lesser degree by mean flow pressures above atmospheric. However, at subatmospheric mean pressures, appreciable increase in permeability occurs for low permeability samples. Air and water relative permeabilities were also measured for numerous samples of Pittsburgh and Pocahontas coals. Tests were performed under steady-state conditions for both drainage and imbibition cycles. Results indicate that the flow of gas is greatly reduced during the latter process, whereas it is largely undiminished over a wide water-saturation range during drainage. It is also shown that imbibition saturation distributions obtained from liquid-water imbibition as opposed to water-vapor adsorption produce gas permeability curves of radically different character. The effective permeabilities to both gas and water were significantly reduced with the application of overburden pressures in the range of 0 to 1,000 psig, but the general shapes of the relative permeability curves remained the same.

Jan 1, 1974

By J. W. Thompson

MEANING OF TERM, The term "minerals" when used in grants or in reservations or instruments of conveyance is not limited to metals or metalliferous deposits, whether contained in veins that have well-defined walls or in beds or deposits that are irregular and are found at or near the surface or otherwise. Byron v. Utah Copper Co., Utah, 178 Pacific 53, p. 58. The term "mineral" in its commercial sense has been defined as any organic substance found in nature having sufficient value sepa- rate from its situs as part of the earth to be mined, quarried, or dug for its own sake or its own specific use. Rockhouse Fork Land Co. v. Raleigh Brick & Tile Co., - W. Va., 97 South- eastern 684, p. 685. CONSTRUCTION AND MEANING. It can not be said that the term "minerals" includes only such substances as are procured by tunnelling and shafting, as much gold is procured by placer mining and rich deposits of manganese and other like ores are found upon the surface of the earth and are some- times obtained without either quarrying or mining. Rockhouse Fork Land Co. v. Raleigh Brick & Tile Co., W. Va. ——, 97 South- eastern 684, p. 685. GRANITE AS MINERAL. It has been determined that granite was included in a grant of minerals. Rockhouse Fork Land Co. v. Raleigh Brick & Tile Co., -W. Va., 97 South eastern 684, p. 685. See Armstrong v. Lake Champlain Granite Co., 147 N. Y. 495, 42 Northeastern 186.

Jan 1, 1919

By G. W. Jones

[The determination of the ignition tcqornturc ol" dict:iyl cther and othylene in air ma o;GrT;en rir..ic'r. is dcscribed In thin report J'IF.R mqdo primarily for comparison rritll sinilnr d~ton:in:~tions of ot; cr co~~o~imS-r, in the same apparatus and using the r?.:?.r.~o 1a.borntorg t cchzllique The investigation was conducted at the 2ittsbur;;h Experiment Station of the United States wcau 02 hii2cs vritEl tl~c cooperation of licrclc & Co., Inc.]

Jan 1, 1935

By Stephen Gerard Sawyer

This report presents a Fortran IV computer program for the structural analysis of space-frame protective canopies used in underground mines to protect equipment operators from falls of roof, face, or rib. This program entitled CANOPY permits rapid calculation of the elastic strength of a canopy for a variety of static loading conditions. Stresses in, and displacements of each structural member are computed and printed out. Additionally, identification of all members that have commenced yielding, weight of the canopy, total loads on the canopy, and maximum loads that the canopy can sustain elastically are output. Program description, input instructions, program listing, and two example problems are included.

Jan 1, 1972

By H. Robert Ensminger

The Belizean economy registered a modest real growth of 1.3% during 1981. The gross domestic product (GDP), based on current prim was $121 million' with an inflation-rate of 10%. The country received $19 million in economic aid during 1981. In early 1981, Belize'e four commercial banks raised the interest on deposits to 15% in an effort to curb capital outflow. During 1981, the financial situation deteriorated somewhat, particularly the balance of payments. For the year the total value of imports exceeded exports by almost $38 million, while the Government continued to maintain a fairly free trade policy. Import duties and term averaged about 8% on essential item and 40% on nonessential ones.

Jan 1, 1983

By Michael G. Zabetakis

The autoignition temperatures (A.I.T.'s) of natural and synthetic lubricants in air were generally found to decrease with increasing pressure. Of the two types of fluids, synthetic and natural, studied in some detail, the phosphate esters had higher A.I.T.'s at any pressure between 1 and 200 atmospheres than the mineral oils. Most of the A.I.T. data obtained in this study obeyed the relationship predicted by Semenov's theory of ignition.

Jan 1, 1962

By Oliver Bowles

A conviction is growing that depressions and other adverse conditions are not entirely unavoidable if a knowledge of past achievements and shortcomings is intelligently, applied in shaping the course of industry. Mineral producers have available a source of such knowledge concerning; their industry in the statistical records of the United States Bureau of Mines, and by scanning, this increasingly exact history can obtain information on which to found a more stable future. This paper contains a brief history, covering more than 50 years, of the activities of the nonmetallic mineral industries as a group, followed by short histories of each of the more important commodities in which are noted the circumstances that lave influenced their development.

Jan 1, 1933

By Kevin M. Connor, O&apos

This report documents-the process of literature review, site selection, instrument installation, data acquisition, and preliminary data reduction performed to evaluate the influence of rock mass discontinuities on coal mine subsidence. A system of surface, subsurface and mine level instrumentation was installed at the Armco No. 7 Mine in Montcoal, West Virginia where the overburden varied in thickness from 630 to 1040 feet. Survey monuments, borehole pressure cells, full profile borehole inclinometer-extensometers, mine level extensometers, stressmeters and tape extensometer convergence stations were installed to monitor displacements and stress changes. Final design of the instrumentation system was based on: a) review of available information, b) field mapping and analysis of areal photography, c) drilling, and d) borehole geophysics. The report contains the complete graphed data of stress and displacements accompanying the longwall mining of a 4800 ft long by 480 ft wide coal panel.

Jan 1, 1983

These proceedings consist of papers presented at Bureau of Mines Technology Transfer Seminars in December 1983 for the purpose of disseminating recent advances in mining technology in the area of mine ground control. The Bureau of Mines conducts several of these seminars each year in order to bring the latest results of Bureau research to the attention of the mining industry as quickly as possible.

Jan 1, 1984

By T. C. Green

A two-phase program evaluated commercial proximity warning devices and then served to design and develop an automatic electrostatic field strength measurement device with improved performance. The Phase I program consisted of test and evaluation of three commercial proximity warning devices, all of which operate on the principle of electrostatic field intensity measurement for determining proximity to high voltage power lines. Performance testing of these devices utilized full-scale cranes and power line systems and a scale model facility. The evaluation results were reported in the Phase I report entitled "Evaluation of Proximity Warning Devices" dated 22 February 1980. Under the Phase II program, a microproressor-based data acquisition system was designed and developed to collect and measure field strength at distributed points around the crane boom. This unit (referred to as the Distributed Sensor AC Electrometer) measures the field strength about a crane boom using 17 distributed sensors. Keyboard control is provided for the equipment operator. Measured field strength values are displayed on a line printer and recorded on magnetic tape. Laboratory testing of this unit demonstrated performance characteristics and field strength measurement accuracy within the design goals. A Phase III measurements program is proposed using the AC Electrometer to map the field strength contours about power line configurations.

Jan 1, 1981

By J. H. Nixon

A three phase program evaluated commercial proximity warning devices, developed and designed a microprocessor-based electrostatic field measurement instrument, and utilized this instrument to investigate the electro-static fields about power lines. The Phase I program consisted of test and evaluation of these commercially available proximity devices. The evaluation results were reported in the Phase I report entitled ?Evaluation of Proximity Warning Devices? dated 22 February 1980. The Phase II program resulted in the design and development of a microprocessor-based Distributed Sensor A.C. Electrometer which measures the electrostatic field present at 17 discrete locations along a crane boom. Operator control of the measurement system allows simultaneous electric field measurements from 17 probes, print out of the electric fields measured, and data archiving on magnetic tape for post measurement analysis. Under the Phase III program, electrostatic fields around a crane boom were measured by the instrument at 17 high voltage power lines of various voltages and geometries. The electric field data was processed and plotted versus boom distance from the power line. Analysis of the electric field data indicate that the distances at which a single sensor alarm will activate, vary by a factor of 3 to 1. This is due primarily to variations in boom orientation. The results also indicate that in the case of multiple power lines, a single electrostatic field sensor cannot reliably be used to determine the distance from a power line.

Jan 1, 1982

By R. V. Ramani, J. M. Mutmansky, P. C. Luna, V. A. Marple, Honglin He, B. A. Olson

The development of a sampling instrument for the assessment of an underground coal miner’s exposure to airborne respirable coal mine dust on a continuous and real-time basis has been long identified as essential for timely initiation of control actions. A respirable dust dosimeter (RDD) which operates on the principle of increasing pressure across a filter media with increasing dust mass on the filter has been developed by the National Institute for Occupational Safety and Health. Comparisons of the performance of the RDD with an U.S. approved gravimetric respirable dust sampler (GRD) have shown that the RDD may meet the requirements for measuring miners’ exposures on a cumulative, near real-time basis such as mid-shift and end of shift exposures. Recently, the performances of the RDD and GRD were compared by conducting side-by-side area sampling experiments in a controlled experimental environment in the laboratory and in underground coal mines under normal operating conditions. In this paper, the results from the in-mine study are presented and discussed. The experimental design for the in-mine study included two mines in different coal seams in different geographic coal regions. To ensure a wide range of concentrations, the experiments were conducted in a continuous miner section in Mine 1, and a longwall face in Mine 2. Airborne dust sampling was conducted for four different shifts at each mine. In each shift, two samples of different exposure durations were collected from two different locations. Each sample consisted of the readings of three dosimeters and the exposed filters from the three paired GRD samplers. As a result, a total of 96 comparative samples were obtained, 48 for each mine. The data were analyzed for the precision of the RDD and GRD measurements and for the relationships between the differential pressure of the RDD and the mass of dust on the paired GRD filter. The analyses indicate that, on the average, the RDD and the GRD track the airborne respirable dust concentrations well, exhibiting both a high correlation between the two measurements and a reliable predictive relationship of one from the other. Details of the experimental design, data analyses procedures, results, conclusions and recommendations of the underground experiments are presented in this paper.

The Bureau of Mines is establishing design criteria for effective roof support systems and is developing technology to improve mine planning and design. Geologic studies, surface and underground mine monitoring, and laboratory evaluations were conducted. The seven papers in this proceedings Information Circular present results of several investigations. Addressed are problems existing in both longwall and multiple-seam mines. Discussions include the effect of dewatering at a longwall mine site in the Pittsburgh coal seam and the effect of chain pillars on subsidence. Other results are measurement and characterization of longwall rock mass movement and an integrated design for stability in multiple-seam mining.

Jan 1, 1987

By David R. Jessey

Water pollution problems associated with surface metal/nonmetal mines throughout the United States were assessed. Three major problems were identified: acid mine drainage (AMD), toxic concentrations of heavy metals and excessive sedimentation. Several factors affect the type and amount of pollutants generated at a mine site. Among these are hydrologic regime, geology, mineralogy, topography, climate, size of the mineralized area and mining method. Nine surface mines situated in distinctly different settings were visited and their pollution problems studied. These mines were located in Morenci, Arizona; Hayden, Arizona; Sauharita, Arizona; Cobalt, Idaho; Spruce Pine, North Carolina; Iron Mountain, California; Butte, Montana; Fernwood, Idaho; and DeLamar, Idaho-Oregon. A detailed evaluation of the pollution problems at the Morenci mine indicated that a diversion system and treatment pint would be the most effective means of abatement for the existing water quality problems. Based on the study of the Morenci mine and three other porphyry copper mines with differing problems a water management plan was conceived for a new source copper mine. A companion Appendix Volume containing detailed reports on the mine site visits is on file at the US Bureau of Mines Spokane Research Center.

Jan 1, 1981

By Joseph L. Ritchey

The Trail Lake RARE II area comprises 1,300 acres (526 ha) in Lassen and Plumas Counties, California, adjacent to the Caribou wilderness. No mining claims, prospects, or quarries are reported within the study areas, and no evidence of potential mineral deposits was found during a field reconnaissance. Quaternary basaltic lava flows uniformly underlie the area. INTRODUCTION The Trail Lake (No. B5-095) RARE II further planning area occupies 1,300 acres (526 ha) adjacent to the Caribou Wilderness in Lassen and Plumas Counties, California. Susanville is about 30 mi (50 km) east and Chester is about 17 mi (27 km) south of the study area. Access from State Highways 44 and 36 is provided by well-maintained gravel roads.

Jan 1, 1981

By Wils L. Cooley

The report covers tests and criteria for the establishment of safe grounding systems for coal mines. The work deals primarily with under-ground coal mines, but much is applicable to surface mines as well. Included is an extensive guide to grounding and bonding procedures for mine surface substations. Xit-Rods are evaluated and shown to deviate from manufacturer's claims. An analysis shows that very long cables are difficult to monitor using audio frequency ground-check techniques. A method is developed to detect failing cable splices without removing the cable from service. Simulation and measurement are compared for a technique to detect bad rail bonds, and an assessment is made of grounding techniques for dc face equipment.

Jan 1, 1979

By Z. Zborovszky

The feasibility of using the nucleation properties of combustion generated particulates for the identification of their sources was investigated, using the Cloud Condensation Nuclei (CCN) Spectrometer. The Investigated materials included coal, wood, belt materials, electrical insulation, brattice cloth, and diesel exhaust. The materials were heated In an oven using filtered air flow, and their time, temperature, and the critical supersaturation spectrum of condensation nuclei (also referred to as the CCN spectrum) produced by the combusting material were recorded. Some data was obtained on a typical metal-mine background containing blasting products. The data was processed and analyzed In an attempt to specify parameters and limits that would allow the identification of the combustion sources. It appears that under controlled test conditions It Is possible to Identify the source on the basis of data derived from the CCN spectrum. More general use of the Idea for fire detection under uncontrolled practical circumstances in an actual mining environment does have potential but would require further research.

Jan 1, 1978

By Robert L. Lagace

This report describes the results of a system study of the factors influencing mine rescue attempts based on the use of electromagnetic VF rescue transmitters by trapped miners and helicopterborne search receivers by mine rescue personnel. The findings cover four main task areas. The first - mine emergency/disaster considerations - concentrates on characterizing the events and key parameters of mine fires and explosions related to trapped miner location and rescue activities. The parameters include critical time periods, affected areas, survival times, response and rescue times, and survival rates. The second - hardware considerations - concentrates on characterizing the relevant properties of VF rescue transmitters, oxygen-type self-rescuers, VF search receivers, helicopter performance, and signal detectability and sensor sweepwidths for helicopterborne sensors. The third - search theory probabilistic model develops a method to identify the most important regions to be searched, and to allocate helicopter-based search effort so as to maximize the number of miners detected in time to be rescued. The fourth - sensitivity analyses and application of the search model - exercises the search model on representative mine emergency/disaster scenarios to assess the impact and effectiveness of helicopter-based searches. Conclusions and recommendations are presented, together with a set of search scenario planning guidelines.

Jan 1, 1982

By CLARENCE G. SMITH

Prior to the actual development of an oil property it is difficult to determine the quantity of oil under the property and the rate at which this oil can be brought to the surface-factors that determine the ultimate value of the property. Consequently, there has been much confusion in devising accounting systems that, during the entire life of a property, will show costs and profits from which the producer can determine whether his property is being worked at a profit or otherwise. The Bureau of Mines publishes this report in recognition of a distinct need for a simple treatise on accounting methods adapted to the peculiarities of the petroleum industry. Probably many companies operating oil wells are not fully acquainted with details important to the welfare of their business, because their account books fail to furnish them with exact and adequate data. With the accountant rests the responsibility of providing the management with reports setting forth the details of the business expressed in fitting terms as well as in dollars and cents. These reports are a means whereby efficiency may be maintained, waste prevented, oil obtained and sold, and money suitably reinvested. They also enable a concern to study the progress of its business in order to conserve to the utmost the possible benefits from an exhaustible deposit of mineral wealth. When managements realize the extent of the waste at their properties more attention will be given to the character of the accountancy records. Herein are presented descriptions and discussions of balance sheets, profit-and-loss statements, and bookkeeping methods peculiarly adapted to the oil business. As far as possible, technical phrases have been omitted in order that those not familiar with accounting terms may be able to follow the subject matter. The systems of keeping books outlined in Chapter X have all been found practical. For brevity as well as clearness the major part of the work refers to the company operating only one property.

Jan 1, 1917

By B. M. Harra, O&apos

Zinc smelting is frequently termed a backward art. The term is hardly true, for great progress has been made in recent years in the design and in the thermal efficiency of the retort furnace, in the quality of retorts, in the recovery of zinc, and in the ability to treat more impure and complex ores. The fact remains, however, that the peculiar physical and chemical properties of zinc have delayed such immense advances-large smelting units, high recovery, low-unit costs, and ability to treat low-grade ores-as have been made in the metallurgy of lead and copper. In current retort-smelting practice, the ores, if carbonates, are calcined to remove carbon dioxide; or, if sulphides, are roasted to remove sulphur. The sulphur must be eliminated as completely as possible, usually to less than 1 per cent. This means that the roast must be continued for a long time at a high temperature, with resulting high cost and small capacity per furnace. The roasted ore is mixed with about 50 per cent of its weight of reducer, which may be fine coke, anthracite, or nonbituminous coal. This mixture is charged into horizontal fire-clay retorts. The retorts used in this country are about 8 inches in internal diameter by 4 feet in length and hold 50 or 60 pounds of ore. The diameter of the retort is limited by the time required for the heat to penetrate to the center of the charge; the length by the strength of the retort, which at the high temperature employed can not support the weight of the charge if the span is more than about 50 inches. The retorts are heated externally by coal, natural gas, or producer gas to a temperature of 1,200° C. or more. The zinc oxide is reduced to zinc, which is volatile at this temperature, and passes into a conical fire-clay condenser attached to one end of the retort, where it condenses to liquid zinc and is removed. Twenty-four hours are required for distillation, and because of the low heat conductivity of the retort walls and of the ore charge itself, the heat efficiency even of the most modern regenerative furnaces is only about 12 per cent. The retorts have a short life, 30 to 60 days, at the high temperature required; zinc

Jan 1, 1923