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By R. E. Heithecker

In June 1933 the Bureau of Mines, in cooperation with the State of Oklahoma and the Oklahoma City Chamber of Commerce, published a report of the gas at reserves in the Oklahoma City oil field3/ based upon data as of October 1932, at which time there were 43 classified gas wells in the field, The estimates were obtained by the ?porosity-area" method. There are two general methods of estimating natural-gas reserves. The porosity-area method, as used by Hill and Rawlins, is used when a gas field is comparatively new but after enough drilling has been done to determine the average thickness, porosity, and areal extent of the producing horizon. The "pressure-volume? method of estimating gas reserves, the method used in this report, nay be used after a sufficient volume of gas has bean withdrawn from the reservoir to cause an appreciable decline in reservoir pressure.

Jan 1, 1937

By Paul G. Swanson

This investigation was conducted to identify the principle causes of spoil instability problems in the Eastern Coal Province. The study was also conducted to develop a matrix to predict the strength and groundwater parameters necessary to conduct stability analyses on a proposed reclamation scheme. Suggestive methods to reduce spoil instability potential are also included. Numerous physical property, strength, compressibility, chemical and mineralogical tests were conducted on mine spoil samples obtained from 11 different surface mine sites. Site characteristics that influence the position of the post reclamation groundwater table were identified. Distinct regions within the Eastern Coal Province with high incidences of surface mine slides or high landslide susceptibility were identified. The application of the predictive matrices developed in this study is for surface mine sites mined and reclaimed in general accordance with the Surface Mine Reclamation Control Act of 1977. A review of current mining practices and the relative effect on spoil stability is included.

Jan 1, 1983

By Herman O. Ankenbruck

Analyses of statistical data indicate that haulage accidents are one of the largest sources of injuries and fatalities in underground coal mines, and that the rate of accidents in transportation has been increasing during the past few years. These previous analyses were performed by correlating accident or fatality data at a rather high level of miner activity. In this present investigation, underground surveys were made by observing conditions and activities in some detail at a rather low level of activity in an attempt to understand factors contributing to hazards in the specific situations observed. The aim of the current study was to derive preventive measures that might obviate the hazardous conditions and unsafe acts observed; and, following this, to provide recommendations for additional research and development to reduce accident potential in underground transportation. The major project tasks are diagrammed together with the task outputs in figure 1-1. Initially, a preliminary study of ell underground haulage operations was performed in order to establish the kinds of data needed and to provide the rationale leading to the data requirement. At the same time, the various types of haulage equipment used for each operation were defined. A preliminary analysis of each type of haulage operation was performed in order to establish the sequence of tasks required to operate haulage equipment. These tasks were transferred directly onto observation forms, and were used in developing interview forms. In parallel with the task analysis, a review was made of accidents and hazards that might occur during each type of operation.

Jan 1, 1975

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

This paper was developed as part of an effort by the National Institute for Occupational Safety and Health (NIOSH) to identify risk factors associated with bumps in the prevention of fatalities and accidents in highly stressed, bump-prone ground conditions. Changes of failure mechanism with increasing confinement, from extensional- to shear-dominated failure, are widely observed in the rupture of intact specimens at the laboratory scale and in rock masses. In the previous analysis conducted in 2018, both unconfined and triaxial compressive tests were conducted to investigate the strength characteristics of some specimens of a Utah coal, including the spalling limits, the ratio of apparent unconfined compressive strength (AUCS) to unconfined compressive strength (UCS), the damage characteristics, and the post-yield dilatancy. These mechanical characteristics were found to be strongly anisotropic as a function of the orientation of the cleats relative to the loading direction.

Jan 7, 2020

By E. E. Buban

A self-contained breathing apparatus has been developed to provide complete respiratory protection for a miner in an irrespirable atmosphere. The apparatus has the desired features of comfort, reliability, maintainability, and quick-donning capability. The apparatus is packaged in a moistureproof envelope and is protected in a shock absorbing, fiberglass resin carrying case. The apparatus is a small, lightweight, one-time-use device that can be readily worn on a miner's belt, requires no maintenance and is designed to have a shelf life of five years and a carrying life of three years. It is deployed to the use position in a period of 15 to 30 seconds. Man tests conducted in-house and at the National Institute of Occupational Safety and Health (NIOSH) testing laboratories established that this unit meets all performance requirements listed in the Code of Federal Regulations, Title 30, Part 11, Subchapter B, Subpart H (CFR 30, Part 11) for respiratory protective devices. The unit, which has received joint approval (TC-13F-37) on a prototype basis from the Mining Enforcement and Safety Administration (MESA) and NIOSH has: (1) Ten-minute service life under escape conditions. (2) Thirty-minute service life when the wearer is at rest. (3) Peak-to-peak breathing resistance of less than our inches water column height. (4) Inspired gas temperature of less than 135°F. (5) Breathing gas contents greater than 19.5 volume per cent of oxygen and less than 2.5 per cent carbon dioxin. (6) A weight (complete in carrying case) of 2.75 lbs. (7) A carrying case size of 6-1/2"x 5-1/8"x 3-1/8".

Jan 1, 1974

By Robert A. Cortese, Henry E. Perlee

Coal dust and float coal dust, produced during normal mining operations, in underground coal mines, are carried from the point of origin downstream by the ventilating air, where it deposits on the surfaces of the mine entry. In an explosion, this dust is lifted from the surfaces by the aerodynamic disturbances and, if of sufficient quantity, can continue to propagate the explosion. To prevent the surface coal dust from contributing, it must be inerted, typically by spreading pulverized limestone, i.e., rock dust, over the coal dust surface. To facilitate the dusting operation, the National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Research Laboratory(PRL), developed an automated system that continuously monitors the accumulation of coal dust. This system could activate a rock-dusting machine that disperses rock dust into the ventilation air when dangerous deposits accumulate and deactivate the machine when sufficient inert has been deposited on top of the coal dust. The system consists of a microprocessor-controlled optical float dust deposition meter. This device measures the light intensity reflected from a deposited layer of dust. A standard cap lamp is used as a fixed-position light source. From the reflected light signal, the microprocessor determines the hazard level of the deposited layer and performs the appropriate action. Full-scale studies conducted in the Experimental Mine at PRL's Lake Lynn Laboratory, using alternating thin layers of rock dust and coal dust, successfully demonstrated the operation of the device. Based on the statistical data from these studies, a mathematical model was developed to predict long-term error in total rock dust content using this inerting procedure. Downwind dust dispersion was also examined to provide optimum placement of the dust sensors and to determine the need for better rock dust dispersion techniques.

Jan 5, 1998

By A J. Cornah

Critical decisions in iron ore project evaluation and production are based on global and local spatial estimates of primary mineral deposit properties (such as in situ geochemical grades) and geometallurgical responses (such as screened, washed or concentrated product yields and grades), which are derived from limited sample data. These spatial estimates are typically made using classical geostatistical techniques, which fundamentally assume that the attributes of interest behave additively. This assumption is generally appropriate for æprimaryÆ variables but æresponseÆ variables may behave non-additively and therefore their direct linear estimates may be biased.In this paper an existing additivity testing mechanism is used to quantify the bias resulting from direct linear estimation of a non-additive iron ore attribute. Data from a magnetite project are used to determine the circumstances under which such biases may be of material impact. The implications for iron ore resource estimation, geometallurgical modelling and grade control are outlined and discussed.CITATION:Cornah, A J, 2013. Assessment of the impact of non-additivity in the estimation of iron ore attributes, in Proceedings Iron Ore 2013 , pp 129-136 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By W. R. Hibbard

The term lineage was first introduced by Buergerl to denote dendritic branches, grown from a crystal nucleus during solidification from the liquid, with imper- fections in alignment of the order of 10 : to 10-4 cm. These imperfections are associated with distortions of the dendrites caused by the subsequent solidification of the inter-dendritic filling and are illustrated in Fig I. Buerger etched zinc single crystals made by the Bridgman3 method to develop this dendritic pattern and show lineage microscopically. Since maximum crystal growth in face-centered cubic metals occurs along the [IT] directions,2 lineage would appear in copper as small deviations of dendritic branches from these directions. Elam4 and others5"8 reported etching effects resulting from coring along the cube face traces of various copper alloy crystals. These traces were used by Samans8 to orient single crystals. Williamson9 noted a "lined structure (in alpha brass single crystals) consisting of an ordered arrangement of etch pits" which were probably traces of {IOO} planes but somewhat uncertain because they were never straight (that is, apparently lineage). Greningerl1 described the distortion and multiplicity of Laue spots in back reflection X ray photograms of copper single crystals showing lineage. The present investigation -includes metal-lographic, X ray, and property studies of lineage in large grain and single crystal specimens of copper. Preparation of Specimens specilnens 10 in. long 35 1/2 in. diam of oxygen-free copper (o.F.H.c.) (99.985 pet) were' melted vertically in graphite crucibles under an atmosphere of commercial nitrogen purified through a gas train including sulfuric acid, potassium chloride, magnesium chiorate, hot copper chips and phosphorus pentoxide. After a temperature of 1200°C had been maintained for 1/2 hr, the furnace was turned off and the specimens cooled at a rate of about 150°c an hour' This method of direct solidification was used by Greningerlo to produce single crystals with marked lineage and in this investigation produced a fair yield of single crystal specimens in

Jan 1, 1949

By W. R. Hibbard

The term lineage was first introduced by Buergerl to denote dendritic branches, grown from a crystal nucleus during solidification from the liquid, with imper- fections in alignment of the order of 10 : to 10-4 cm. These imperfections are associated with distortions of the dendrites caused by the subsequent solidification of the inter-dendritic filling and are illustrated in Fig I. Buerger etched zinc single crystals made by the Bridgman3 method to develop this dendritic pattern and show lineage microscopically. Since maximum crystal growth in face-centered cubic metals occurs along the [IT] directions,2 lineage would appear in copper as small deviations of dendritic branches from these directions. Elam4 and others5"8 reported etching effects resulting from coring along the cube face traces of various copper alloy crystals. These traces were used by Samans8 to orient single crystals. Williamson9 noted a "lined structure (in alpha brass single crystals) consisting of an ordered arrangement of etch pits" which were probably traces of {IOO} planes but somewhat uncertain because they were never straight (that is, apparently lineage). Greningerl1 described the distortion and multiplicity of Laue spots in back reflection X ray photograms of copper single crystals showing lineage. The present investigation -includes metal-lographic, X ray, and property studies of lineage in large grain and single crystal specimens of copper. Preparation of Specimens specilnens 10 in. long 35 1/2 in. diam of oxygen-free copper (o.F.H.c.) (99.985 pet) were' melted vertically in graphite crucibles under an atmosphere of commercial nitrogen purified through a gas train including sulfuric acid, potassium chloride, magnesium chiorate, hot copper chips and phosphorus pentoxide. After a temperature of 1200°C had been maintained for 1/2 hr, the furnace was turned off and the specimens cooled at a rate of about 150°c an hour' This method of direct solidification was used by Greningerlo to produce single crystals with marked lineage and in this investigation produced a fair yield of single crystal specimens in

Jan 1, 1949

By Harold E. Marr

A simple algorithm is presented for processing digitized X-ray spectra obtained with a Si(Li) or Ge(Li) semiconductor detector coupled to a multi- channel analyzer. The simplified least-squares procedure is used to smooth out the statistical fluctuations in the spectrum by repeatedly fitting a quad- ratic equation to a predetermined number of channels and performing a traveling smooth across the spectrum. A logarithmic transform is applied to the raw data to minimize the distortion of the gaussian-shaped peak profiles. The efficacy of the technique is evaluated by observing the distortion of several gaussian-shaped peaks that have been subjected to the smoothing operation. The locations of maximums and minimums in the spectrum are predicted in the process as well as the values of the peak heights. The convolution integers from a least-squares fit of a quadratic equation are calculated as part of a FORTRAN subroutine. The building-block approach to computer programing in a small laboratory is discussed.

Jan 1, 1972

By G. R. Moulder

A device was developed that measures dynamic stress (ultrasonic energy) transfer through installed rock bolts, a measure that is directly proportional to the degree of grout bonding of the bolt to the mine roof structure and thus the ability of the bolt to bear static stress. The rock bolt bond tester (RBBT) is a hand-held portable device that shows three ranges of bolt bond condition; i.e., one-third (Bad bond), two-thirds (marginal), or fully bonded. These are shown respectively by a red, yellow, or green light that displays for 4 s. RBBT performance was verified with 2 1/2-to 8-ft bolts installed in various types 0f mine roof structures (sands tone, shale, and boney coal-mud), and 15 now being tested by the Bureau of Mines in mines across the United States. The unit is about the size of a five-battery flashlight and contains the transducer electronics, and battery pack. The RBBT is designed for extreme ease of operation, requiring only manual contact with the bolt and signal read-out. The batteries are rechargeable and the package is designed for durability in a mine environment.

Jan 1, 1983

By Nikolaos Polysos, Holger Witthaus

INTRODUCTION The classification system for German coal mining is the result of approximately 100 years of experience in roadway development and longwall mining. It is also based on different research projects covered by national and European research programs. Over the past 30 years, more then 600,000 m of road-ways have been driven and employed for mining activities. To properly describe the German rock mass classification system, therefore, it is useful to take a look at the main geomechanical preferences and common support systems. The decision about the most effective development technique and support system is based on a synthesis of rock mass classification and geomechanical analysis. The properties of surrounding rock, the in situ stress, and the influence of mining activities in several seams at each German mine must be considered for the evaluation of the expected deformation of the roadway. The mine layout, the requirements of ventilation and fire prevention, as well as the need to maintain emergency escape routes for the miners, require that the gate roads remain usable after the passage of the longwall face in most cases. Moreover, the gate roads must be maintained despite the high stresses that are applied during longwall retreat mining. Therefore, gate road design must address a broad spectrum of potential deformation environments. In the past, when gate roads were supported solely with yielding steel arches, lithologic descriptions of the surrounding strata conditions were adequate for the dimensioning of support and the prediction of the roadway deformation. The current conditions of multiple-seam mining at depths of up to 1,700 m require combined support systems, including pattern bolting and backfilled steel arches. Rock bolt support is used for development, after which (typically 50–100 m outby the face) the steel arches are installed and backfilled with building material (concrete) in order to achieve an optimized development rate. The rock mass classification system described below was developed especially for the conditions of German hard-coal mining. It includes the stress distribution caused by multiseam workings (including crossing goaf edges of former longwalls), as well as in situ stresses due to greatdepth and the presence of tectonic faults. It is based on the evaluation of four parameters: • Geotechnical analysis of drill cores • Geotechnical observation of the development face • Geotechnical classification of tectonic structures (faults) • Standard classification derived from geotechnical assessment and evaluation of stress conditions (using numerical modeling for stress calculation) ROCK STRENGTH One of the most important input parameters for describing strata conditions is the strength of the rock. The German classification system is based on a description of lithotypes. This method has been used successfully since the 1950s and is based mainly on the uniaxial compressive strength (UCS) of the material. An evaluation of the rock strength observed in a survey of approximately 82,500 samples of rock core yielded the results shown in Figure 1. The three most common coal measure rock types are mudstone, siltstone, and sandstone. Each shows a specific mean UCS level and a different spread between the minimum and maximum values. Sandstones, in particular, have a wide spectrum of compressive strength, ranging from approximately 40 MPa to greater than 130 MPa, with an average of 85 MPa. The causes of this wide range include different sedimento-logical preconditions, facies, and digenetic processes. [ ]

Jan 5, 2007

By M. E. Wadsworth, J. R. Lewis, J. M. Quets

Samples of snythetic magnetite were reduced in hydrogen at various partial pressures and temperatures. The reaction mas found to be surface controlled and directly proportional to hydrogen partial pressure over the temperature range studied (400° to 1000°C). A transition in the mechanism occurred at approxirnately 590°C. This has been attributed to a change in the slow step of the reduction reaction resulting from the presence of stable wüstite at higher temperatures. Below 590°C the heat of activation for the reduction was found to be 14,700 cal per mole and it was 3,200 cal per mole above 590°C. THE reduction of the oxides of iron has been a subject of study and interest for many years. Edstrom1 has reviewed the work up to 1953 and his findings provide much basic information concerning details of the reduction of hematite (Fe2O3 ) and magnetite (Fe3O4) with both H2 and CO. He concluded that below 600°C the reduction of both hematite and magnetite was essentially identical, since the rate was controlled by a surface reaction at a magnetite gas interface and the iron formed was very porous. The decrease in the reduction rate for both hematite and magnetite immediately above 600°C was attributed to the formation of a stable wüstite phase across which diffusion was very slow. The wide difference in reduction kinetics for hematite and magnetite above 600°C was explained in terms of the character of the wüstite formed. The rate of magnetite reduction increased slowly with temperature beyond the minimum immediately above 600°C and rates equivalent to those observed at 550°C were not obtained until the temperature was increased beyond 850oC. Edstrom and Bitsianes2 studied the solid-state reduction of magnetite, the reaction of which can be written (4x-3)Fe + Fe3O4—4 FexO [1] where x is between 0.83 and 0.95. The rate was found to be controlled by the kinetics of transport of iron ions through the wüstite phase. Bogdandy and Riecke3 studied the kinetics of reduction of small grains of iron oxide in hydrogen and qualitatively attributed the slow step in the reduction process to the diffusion of hydrogen and water vapor through pores. McKewan4 has analysed the data of Joseph,5 Stalhane and Malmburg,6 and Lewis7 and has demonstrated that the kinetics of reduction of both hematite and magnetite are controlled by surface reactions and also that the variation in surface area during reduction must be accounted for. McKewan was able to correlate the reduction data by the equation rodo[1-(1-R)1/3] = Kt [2] where ro is the initial particle radius, do is the density of the iron oxide, R is the fraction reduced at time t, and K is a rate constant. The applicability of Eq. [2] for temperatures above 600°C where a stable wüstite phase is present, indicates the slow step in the over-all kinetics does not result from diffusion unless diffusion occurs laterally along the oxide metal interface or through a wüstite layer of constant thickness. Diffusional control through a layer of wüstite is unlikely, however, in view of the pressure effects demonstrated by Tenenbaum and Joseph,' Diepschlag,9 McKewan,10 and the results of the present study. McKewan has demonstrated a linear rate dependence on the hydrogen partial pressure over the temperature range 400" to 1050°C for the reduction of hematite.

Jan 1, 1961

By D. V. Roberts

Approximately 800 private consulting engineering firms in America specialize in geotechnical engineering. The gross income from these firms totals about $500 to $600 million per year. Sixty-five to seventy-five percent of this geotechnical work is per­formed by consulting engineers that belong to the Association of Soil and Foundation Engineers (ASFE). This paper presents statistics concerning the business activities and functions provided by ASFE member firms. The procedures used in typical projects are described. The paper concludes with a summary of major trends which are impacting the American geotechnical practice today.

Jan 1, 2010

By Cynara Christ Klippel

Devido às exigências de teores de fosforo cada vez menores no aço, o processo de desfosforação tem ganhado destaque nas indústrias. Para aproveitamento das melhores condições termodinâmicas a etapa mais eficiente para o processo de desfosforação ocorre no ferro-gusa. Esse trabalho utilizou quatro misturas iniciais de composição definida com base na literatura, juntamente com o ferro-gusa para ser simulado o processo de desfosforação. A simulação foi feita através do software de cálculos termodinâmicos FactSage e através dos resultados obtidos do programa foram feitos cálculos para avalição da eficiência do processo. Além disso, também foram feitos cálculos baseados na literatura para comparação de resultados e estudo mais aprofundado dos resultados. Os resultados obtidos comprovaram a teoria inicial de que menores temperaturas favorecem o processo.

Aug 17, 2017

By Syd S. Peng

Mountaintop removal (MTR) mining started in West Virginia nearly 30 years ago. This surface mining method can extract multiple coal seams as thin as a few inches in whole and minimum rock dilution in very steep mountainous terrain. MTR is highly efficient, even if coal seams are in close proximity and small in a real extent. Consequently, MTR has been widely used in the Central Appalachian coalfield (mainly Kentucky, Tennessee, Virginia and West Virginia) with great success. In that respect, there has been no demand for research and little scientific research has been performed to investigate its impact on the surrounding area. During the past two years, however, the debate over MTR mining has grown quickly and has become very intense. This article describes chronologically issues raised by various parties, legal actions, impacts on mining permit applications and research projects developed to address the issues.

Jan 1, 2000

By Cynara Christ Klippel

Devido às exigências de teores de fosforo cada vez menores no aço, o processo de desfosforação tem ganhado destaque nas indústrias. Para aproveitamento das melhores condições termodinâmicas a etapa mais eficiente para o processo de desfosforação ocorre no ferro-gusa. Esse trabalho utilizou quatro misturas iniciais de composição definida com base na literatura, juntamente com o ferro-gusa para ser simulado o processo de desfosforação. A simulação foi feita através do software de cálculos termodinâmicos FactSage e através dos resultados obtidos do programa foram feitos cálculos para avalição da eficiência do processo. Além disso, também foram feitos cálculos baseados na literatura para comparação de resultados e estudo mais aprofundado dos resultados. Os resultados obtidos comprovaram a teoria inicial de que menores temperaturas favorecem o processo.

Aug 17, 2017

By J. W. Gabelman

A study of spatial relations between uranium and other metal deposits and hydro thermally altered rocks in western Colorado demonstrated districtwide and regional zoning. The pattern was later found repeated elsewhere in the Western Hemisphere Cordillera. District mineralization centers are pipelike bodies of pervasively altered rock from which intensity-temperature-pressure gradients decreased outwardly. Uranium occurs in several zonal environments but usually is economic only in outermost zones. The general similarity of zones throughout the tectoni-cally and metallogenically uniform Cordillera may reflect a consistent hydrothermal process involving zoning. By determining positions of zones it should be possible to select for examination the most favorable small portions of districts or provinces. Mineralogical zoning has been discussed by Lindgren,l3 Graton,lo Emmons,' Blanchard,' Park and many others. It is commonly found to some extent in most mineralized areas. The existence of nonmetallic alteration envelopes around lode metal deposits and their relation to metallization were first emphasized by Lovering,l4 Burbank, Sales and Meyer," Sales,2o McKinstry,I7 Lovering and others15 and Schmitt. Also, large areas of nonmetallic alteration containing porphyry-type replacement metal disseminations have long been recognized and are described by Schwartz,25-28 Kerr and others" and Gilully. In some districts, e. g., Bingham Canyon, Utah, and Santa Rita, N.M., base metal lode deposits and their alteration envelopes are zoned around large altered areas which contain porphyry copper replacement disseminations; however, the spatial and genetic relations between lodes and replacement disseminations and their associated alterations do not seem to have received sufficient attention. Bodies of altered rock containing porphyry-type replacement disseminations are many times larger than the alteration envelopes containing lode deposits. The two types are rarely superimposed. They occur adjacent to or independent of one another, but they are believed to be related through the mechanism of zoning as suggested by Gabelman and Boyer. 5'6 Most of the significant lode metal deposits are distributed around central pipelike bodies of strong, pervasive, nonmetallic alteration which may or may

Jan 1, 1962

The New South Wales coal industry is a highly mechanised well organised industry which has developed from an annual production of slightly less than 13 million tons in 1950 to over 33 million tons in 1969. Although continuous miners were not introduced into the mines until 1950, by Jillle 1969 the percentage of coal won by these units was 87.3. The paper describes mining conditions in the various coalfields of the State, their complexities and problems and how these have been dealt with. The introduction of fully mechanised long wall faces has presented a challenge which has been accepted and descriptions of systems in use are discussed. Major expansion of the industry is anticipated to meet the requirements of the growing Australian steel industry, for local power generation and to meet the increasing demands of overseas markets.

Jan 1, 1971