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This is the third in a series of reports on properties of commercial motor fuels, made in accordance with a cooperative agreement between the Cooperative Fuel Research (C. F. R.) Committee and the Bureau of Mines of the Department of the Interior. The first report gave data on motor gasolines sold during the winter of 1935-36.3/ The second report gave the same data for motor gasolines sold during the summer of 1936)4/ As was the case with the first cooperative gasoline survey, reports were received for some areas from only one company and in other areas from two companies that did not in all instances report on the same brands of gasoline. In still other areas reports were received from five or six companies on the same brands of gasoline. Thus, it can be seen that data on gasolines are unequal in regard, to the number of reports that were averaged in calculating the data shown in table 1. The data from the Pacific Coast were averaged by the Pacific Coast technical group before submission and are published exactly as they were submitted.

Jan 1, 1937

This is the third in a series of reports on properties of commercial motor fuels, made in accordance with a cooperative agreement between the Cooperative Fuel Research (C. F. R.) Committee and the Bureau of Mines of the Department of the Interior. The first report gave data on motor gasolines sold during the winter of 1935-36.3/ The second report gave the same data for motor gasolines sold during the summer of 1936)4/ As was the case with the first cooperative gasoline survey, reports were received for some areas from only one company and in other areas from two companies that did not in all instances report on the same brands of gasoline. In still other areas reports were received from five or six companies on the same brands of gasoline. Thus, it can be seen that data on gasolines are unequal in regard, to the number of reports that were averaged in calculating the data shown in table 1. The data from the Pacific Coast were averaged by the Pacific Coast technical group before submission and are published exactly as they were submitted.

Jan 1, 1937

By Gale D. C, Giles D. E, James Parker A

A zinc-lead-iron sulphide concentrate from McArthur River can be leached at atmospheric pressure in aqueous solutions with HCI, FeCl3, CuCI2, HCl/02 HC1/02/ CuCI2, Cl2, and CI2/CuCI2 to extract >98 per cent zinc, >90 per cent silver, and <15 per cent iron in 1-7 h at 95°. Galena is more reactive than sphalerite and is converted to lead chloride. Except for leaching with HCI, elemental sulphur is the the main by-product of the leach with little or no sulphate ion detected. The rates and products of these reactions are compared. It is recommended that aqueous slurries of the concentrate (50 per cent w/v) are leached at atmospheric pressure with Cl2 in the presence of copper(II) chloride, which accelerates the extraction of zinc. Hydrochloric acid is a by-product which is consumed bYJeaction with fresh concentrate in air at 60°. Copper is subsequently stripped from the leach solution and recycled by reaction with fresh concentrate at 100°. The separation, recovery, and electrolysis of zinc and lead chloride is outlined since this process would produce Cl2 gas which can be recycled and used directly in the leaching stage.

Jan 1, 1976

By N. V. Moraka

Mining companies are required by law to improve representation of women on their boards. However, progress in this regard has been slow. Boards of directors play an important role in formulating corporate strategy, risk assessment, and effective governance for sustained financial performance. Although some women have successfully maintained board seats, others have been unable to do so. It is difficult to ascertain whether women are being appointed as tokens to satisfy social pressures, as little is known about the experiences of women board members in mining, which may inform or refute tokenism. In-depth interviews were conducted with 20 women and 16 men across six listed mining companies. Thematic data analysis revealed evidence of tokenism where recruitment to mining boards is compliance-based and is informally driven by influential directors. Adverse boardroom experiences that further confirmed tokenism were reported by women, such as disregarding their contributions, condescending behaviour, and limited influence in decision-making, while other women sought to validate their competence and oppose social exclusion. This study recommends that a strong Board Chair and nominations committee is critical to ensure sustainable recruitment of competent and suitably qualified women; and further foster a culture of inclusivity and valuing gender-diverse boards.

Dec 13, 2023

By Hubert E. Risser

Although, for about a half-century the percentage of coal production provided through strip mining has steadily increased, recent trends indicate that a peak in percentage (not tonnage) is being approached, principally because of the decline in economic adrantage enjoyed by strip mining compared to underground mining. Factors contributing to the decline are the decrease in the margin of advantage in manpower requirements held by strip mining; an increase in depth and volume of overhurden, requiring larger equipment and capital investment; increasing lack of reserve land blocks large enough to support extensive strip mining operations; more stringent legislation for reclamation of stripped land, with increasingly higher costs of such reclamation; and the increasing costs of land surface rights for strip mining. Already there has been a peak and suhsequent decline in relative importance of strip mining insome major Eastern coal-producing states; trends indicate that a peaking for the whole Eastern region is on the way. Although, in the West the pressures are less severe, they will, nevertheless, reduce to an increasing degree the advantage that strip mining has possessed. For about half a century, strip mining has been providing an ever-increasing share of total coal output in the United States, and in the past 30 years this share has grown from less than 8% to 33.7%, as shown in Fig. 1. Fig. 1 also shows that strip mining is gaining faster in the West than in the East. From 1961 to 1967, output from strip mines grew 63.6 million toqs, or 52.2%. Certainly there is nothing in such performance to indicate any peaking in the level of strip coal-mine production. But the fact is that, if not in actual tonnage, strip mining appears to be reaching its peak in relative importance, at least east of the Mississippi River. And the area east of the Mississippi provides 90.0% of the strip and 94.9% of the total coal production of the nation. The relative economic advantage which spurred strip mining's growth for a third of a century has been diminishing markedly in recent years. Fig. 2 shows evidence of this decline. From 1947 until 1961, strip tonnage output remained fairly stable, at the end of the period showing only a 12.5% decline. Meanwhile, underground coal production fell 44.5%. As the result of the greater decline in underground coal, strip coal in 1961 furnished 30.3% of the total coal produced, compared to only 22.1% in 1947. In the succeeding six years, however, underground coal output increased by 76.5 million tons, while strip output increased only 63.6 million. Further evidence of the strengthening of underground coal's relative position — or if you will, the weakening of strip coal's position — can be found in the major coal stripping states: Illinois, West Kentucky, Ohio, Pennsylvania, Indiana, and West Virginia, which in 1966 provided 80% of the nation's strip coal. Fig. 3 shows what has been happening in three states lying in the Appalachian field and in the total output of these three states. In the figure, the column height represents the output of coal mined by all methods. The number at the base of each column is the percentage mined by stripping. In Pennsylvania and Ohio, the percentage of strip mining increased between 1956 and 1961, but by 1966 had declined from the 1961 level. In West Virginia, a decline occurred during the first five years but was followed by a rise. In January 1968, Coal Age published an article listing the locations and capacities of new large mines in the planning and construction stages that would be operating by 1968-1971. The plans for West Virginia and Pennsylvania indicated all the new mines would be underground. Except to the extent they might replace existing under-

Jan 1, 1970

By W. G. Pariseau

A crown pillar cave occurred at the Ropes Mine in December, 1987, that resulted in closure of the mine. Production was resumed soon afterwards with the formulation of a rock mechanics plan designed to address several issues of safety and stability. The plan proved to be successful and shows what can be accomplished in the realm of applied rock mechanics where a cooperative atmosphere exists.

Jan 1, 1989

By Helge Rosenberg

Up to now, Topsøe WSA (Wet gas Sulphuric Acid) plants have been in operation for almost 30 years, and close to 80 plants have been sold. In spite of its unique features and ability to treat gases without any prior drying, the WSA technology has had certain restrictions with regards to SO2 concentration in the feed gas, and the overall conversion of SO2 by catalytic means has been limited to approx. 99.7%. In commercial scale sulphuric acid production on the basis of elemental sulphur and metallurgical off-gases, there is a demand for higher SO2 conversion and treatment of gases with a higher content of SO2. Therefore Topsoe has further developed its WSA technology to cope with these demands. This paper will explain more about the principles of such new development and leave the delegate with a better understanding of the potentials of the new generation of the WSA technology from Topsoe.

Jan 1, 2009

By J Wei, A Yo, R Levy

Waste water reuse from municipal and industrial effluents is becoming increasingly important in many areas around the world. Water scarcity, local regulation and environmental impact are driving many industries like coal and copper mines to reuse the large volume of waste water they produce. For example, the Chinese coal industry generated about 4.2 billion tons of mine waste water in 2005 of which only approximately 30 per cent was reused. Coal energy represents 76.6 per cent of the total energy generated in China in 2007 and most of the coal-fired power plants are located in north-west of China, which is a water stressed area.The selection of mine waste water treatment process is challenging as the effluents typically contains high levels of organic compounds and salinity and their composition can vary significantly. In recent years there has been a growing interest in the integration of ultrafiltration (UF) and reverse osmosis (RO) membrane technologies for mine waste water treatment and reuse.In this paper, an overview of the design and performance of ultrafiltration and RO membranes applied for reuse of mine waste water are discussed. A study was carried out in two effluents treatment plants treating copper and coal mine waste water, which are located in Chile and China respectively. The following topics will be discussed to demonstrate the performance of an integrated membrane system in mine waste water reuse: The main challenges from copper mine waste water treatment: high level of chemical oxygen demand (COD); high level of total suspended solids (TSS); high salinity; high concentration of silica, sulfate, iron and other contaminants; and fluctuation of raw water quality. The main challenges from coal mine waste water treatment: high level of total dissolved solids, and waste water quality fluctuation. Design parameters for waste water treatment systems: Selection of pretreatment for dual-membrane system in the copper mine: Clarifier with coagulation and flocculation to remove high TSS; Dissolved Air Flotation (DAF) to remove non-settling solids; Media filtration to handle fine solids and particulate organics; Activated Carbon filters (ACF) to remove dissolved organics, colour and odours. Selection of UF and RO membranes and specific design of their recovery, flux, chemical dosage and cleaning regimes. Finally, the performance of UF and RO, including the main fouling factors and efficient cleaning procedures, will be presented and compared to the design parameters to demonstrate the efficiency and performance of the selected integrated membrane systems in each case.

Jan 1, 2009

Mining One (M1) is often challenged with the task of evaluating deposits considering open cut and/or underground (UG) mining methods. In many near surface deposits a combination of both methods results in the optimum economic means of exploitation. As common as it is to have open pit mines eventually develop into underground mines, theory associated with determining the optimum underground/open pit interface location continues to be subject to refinement. With recent developments in underground software packages, the generation of rudimentary underground mining stopes from basic economic inputs is not only fast, it provides a practical underground mining solution. The determination of the open pit/underground interface is not new to Gemcom's Whittle 4X (Whittle). However, its solution has only ever claimed to be indicative, mainly due the rudimentary nature of how Whittle represents any potential underground mining. The efficient generation of the aforementioned underground mining solution has provided mining engineers with a unique opportunity. Underground mining can now be represented within the Whittle environment to allow the open pit/underground mining scenario to be modelled with increased accuracy. Providing Whittle with the ability to now consider mineable underground stopes combined with the consideration of time value of money (discounting), has delivered a solution with higher credibility than ever before.This paper will elaborate on the potential value gains associated with improved accuracies in the modelling of any potential underground mining in the Whittle environment. Furthermore, it will explain the importance of incorporating time value of money in the optimisation process to provide a consistent solution through to pit selection and final analysis.

Dec 6, 2010

By R. Dass

Paper written on project work carried out in partial fulfilment of B. Sc Eng (Extractive Metallurgy) degree Screening is an industrial process that splits material at a specific cut size into one fraction of particles larger than the cut size and another fraction of particles smaller than the cut size. Particles are vibrated to increase the probability of them being accurately classified and to move the oversize particles off the screen surface. In conventional screening, the screen mesh vibrates with a single frequency and the particles on the screen are all exposed to this same frequency. The Ultimate Screener (see Figure 1) is a new screen technology that imparts multi-frequency vibrations to the screen mesh so that different parts of the screen surface vibrate at different frequencies. The Ultimate Screener incorporates an additional deck that holds the multi frequency adapters as shown by Figure 2. These special adapters can transform single frequency vibrations into multi frequency vibrations. When the screen motors are switched on they begin to vibrate. This vibration is transmitted to the adapters via the body of the machine. The adapters then modify the vibration to have multiple frequencies, which are transmitted to the screen surface via resonating rings.

Jan 1, 2004

By AIME AIME

WITH the recent increase in the price of gold, its economic recovery at depths formerly considered impractical has become a present possibility. Two important difficulties must be met: pressure bursts of the rock, and the reduced efficiency of human labor subjected to the higher temperatures and the increased humidity at the greater depths. In the following abstract of a paper by J. H. Dobson, presented before the South African Institution of Engineers on

Jan 1, 1935

By P. den Hoed, R. I. Rambiyana

"Four sulphide minerals - pyrite (FeS2), pyrrhotite (Fe1-xS), pentlandite ([Ni,Fe]9S8), and chalcopyrite (CuFeS2) - contain the base metals and most of the iron in concentrates of platinum group metals (PGMs). In the pyrometallurgical processing of PGM concentrates these sulphides form a matte during smelting, and iron and sulphur are removed from the matte during the converting process. This paper discusses the roasting of Merensky concentrate in air before smelting, with the purpose of reducing the matte load to the converter.Roasting tests were conducted in a bench-scale rotary kiln at temperatures from 350°C to 700°C. The concentrate tested contained 17.4% sulphur and consisted of 23% pyrrhotite, 16% pentlandite, 11% chalcopyrite, and 2% pyrite. The particles were fine (d50 = 22 µm), and all the sulphide particles were liberated. Roasting in air at 550°C and 650°C for 20 minutes removed respectively 60% and 70% of the sulphur. The iron in the sulphides was oxidized to Fe3O4 (magnetite) at temperatures below 500°C and to Fe2O3 (haematite) at temperatures above 550°C. At 700°C the bed sintered and copper oxides formed. At temperatures below 450°C oxidation was incomplete: pyrrhotite remained and only 30% of the sulphur was removed. Smelting tests were conducted to assess matte fall and the deportment of copper and nickel to matte. It was evident that roasting resulted in lower matte falls (a drop of approximately 60%) compared with matte falls from unroasted concentrate. The iron and sulphur levels in the matte were reduced to below 3.5% and 22% respectively.This paper also briefly describes the mechanisms by which pyrrhotite, chalcopyrite, and pentlandite are oxidized during roasting. For chalcopyrite, the mechanism proceeds through an intermediate solid solution phase, which extends from Cu1.02Fe1.04S2 to Cu2.04Fe0.72S2 to a copper-rich solid solution of bornite (Cu4Fe1.4S4-Cu2S). The oxidation of pentlandite proceeds through a monosulphide solid solution (Ni0.39Fe0.53S-Ni0.74Fe0.15S) to a solid solution of heazlewoodite ([Ni,Fe]3}xS2). These mechanisms are explored in relation to chemical thermodynamics and microstructures."

Jan 1, 2015

By M. Maleki

Variogram analysis and kriging lack robustness in the presence of outliers and data with long-tailed distributions, which often arises when estimating grades in precious metal deposits. The capping technique, consisting of truncating the data to some top-cut grade, is widely used in order to mitigate the influence of the values in the upper tail of the distribution. However, this procedure omits part of the grade variability and is likely to provoke a bias in the estimates. To avoid these issues, a recently proposed approach is to decompose the grade of interest into three components (the truncated grade, a weighted indicator above the top-cut grade, and a zero-mean residual) and jointly estimate the truncated grade and the indicator by cokriging. This approach is attractive as it provides unbiased grade estimates, allows choosing the ?optimal? top-cut value, and essentially works with truncated and indicator data, thus avoiding the use of outlying values for calculating sample variograms and performing spatial interpolation. This work presents an application of this approach to a disseminated gold deposit that has been identified through exploration drilling. The effect of using an indicator covariate is assessed through leave-one-out cross-validation, by comparing the grade estimates with the true grades and with the grade estimates obtained with the conventional capping approach, which considers only the truncated grade as the variable of interest. As a result, cokriging the truncated grade and the indicator above top-cut grade outperforms the conventional capping approach, yielding significantly more accurate estimates. A few complementary guidelines are provided for validating the model hypotheses and for the implementation of cokriging.

Jan 1, 2014

By K. Takahashi, I. Iwasaki

it is well known1 that racemic mixtures of optical isomers can be separated by passing their solutions through a column packed with r- or 1-quartz powder so that one of the isomers becomes adsorbed selectively on the asymmetric quartz surfaces. Although the natural occurrence of r- and 1-quartz is more or less equally distributed, some localities show enough deviations toward a higher proportion of l-quartz2 to suggest that optical isomerism might influence quartz flotation. Beta-amines have an asymmetric carbon atom, and therefore optical activity may be expected. Beta-amines are reported to behave quite differently from alpha-amines in the flotation upgrading of certain oxidized iron ores.3 It is of interest, for both practical and theoretical reasons, to determine whether or not optical isomerism plays a role in the amine flotation of quartz. In this article the results of Hallimond tube flotation tests and of adsorption measurements using d-beta-phenylisopropylamine on both r- and 1-quartz are compared. D-beta-phenylisopropylamine was chosen for the tests because it is commercially available in optical isomers. MATERIALS AND METHODS Brazilian quartz crystals were hand-sorted according to the difference in trigonal trapezohedral faces, and each crystal was further checked by the Airy's spiral.4 The respective crystals were then crushed, and the -150 + 200-mesh fractions were screened out for the Hallimond tube tests. The samples were cleaned by brief leaching with warm, dilute hydrochloric acid, and then by repeated rinsing with distilled water. In preparation for the adsorption measurements, they were then dry-ground in a pebble mill for several hours, washed a few times with distilled water, and finally dried in a vacuum desiccator. By means of the Krypton gas adsorption method, the specific surfaces of r- and 1-quartz samples were determined to be 27,700 and 19,800 sq cm per gm respectively, the difference being due mainly to the decantation procedure rather than to the inherent difference in their grindability. D-beta-phenylisopropylamine was the only collector used in the study. It was solubilized by neutralizing with 110% of the stoichiometric requirement of 0.1 N hydrochloric acid. The specific rotation of the d-beta-phenylisopropylamine was determined with a polari-meter using sodium D line to be, Although the d-beta-phenylis~prop~lamine showed absorption maxima in the wave length region of 250 to 270 millimicrons, due presumably to the phenyl group, these peaks were too sensitive to be used for colorimetric determination of the residual concentration in the adsorption measurements. The amine-picrate method, used in the colorimetric analysis of dodecylammonium chloride,' was found to work satisfactorily for the d-beta-phenylisopropylamine. The adsorption densities were thus determined after equilibrating 40 gm of the ground quartz sample with 300 ml of solution by tumbling in separate glass-stoppered Erlenmeyer flasks for one hour. EXPERIMENTAL RESULTS Fig. 1 presents the adsorption densities of d-beta-phenylisopropylamine on the r- and 1-quarts in the pH range of 6 to 7.5. In agreement with data reported in the literature, the adsorption density of d-beta-phenylisopropylamine was slightly higher on the r-quartz than on the 1-quartz, although the difference was not as pronounced as one might expect from the capacity of r-quartz and 1-quartz to separate racemic

Jan 1, 1969

By Reynold Q. Shotts

A study was made of the coal resources of an area in Jackson County, Ala., forming a part of the Flat Rock, Henegar, and Stevenson quadrangles. The area studied is a portion of the Plateau coalfield on Sand Mountain and is near the Tennessee Valley Authority's Widows Creek steamplant. Since no detailed geological study of this area had been published, some reconnaissance work was done. The coalbeds and adjacent strata such as sandstones, conglomeratic sandstones, and conglomerates were studied. Available drill logs, together with the areal geology, provided sufficient information to permit correlation of the coalbeds and an estimation of coal reserves. For all categories of reserves, computed on a regional basis, a total of 72,920,000 tons of coal more than 14 inches thick is estimated for the areas studied in Stevenson, Flat Rock, and Henegar quadrangles. Of this tonnage, 40,001,000 tons is estimated to have less than 60 feet of overburden. The total measured coal reserves for the above three quadrangles are 16,359,000 tons, with 12,411,000 tons under less than 60 feet of cover.

Jan 1, 1966

By Donald F. Rapp, Thomas E. Brown

The application of commercial explosives in an underwater environment, sometimes referred to as submarine blasting, presents the blaster with a unique set of demanding conditions which require exacting detail in design and application. There are two basic methods for removing rock under water: 1) "the drill and blast method"; and 2) "the dobying method." Because it is a far less effective method of blasting, dobying will not be addressed in this 'paper but suggested criteria can be found in the 16th Edition of the **DuPont Blasters' Handbook" page 371. Some examples of submarine blasting utilizing the drill and blast method include channel expansions, harbor construction, bridge pier footer excavations, utility excavation and demolition work.

Jan 1, 1994

By Dennis R. Dolinar

Controlling coal mine roofs subjected to high-horizontal stress conditions has always been difficult and uncertain. Traditional supports such as wooden cribs and posts, concrete donut cribs, and standing supports collapse and fail when the roof and floor move horizontally as mining progresses. The former U.S. Bureau of Mines (USBM) (currently the U.S. Department of Energy (DOE)), in cooperation with Western Fuels-Utah, Incorporated, conducted research to provide an alternative for traditional secondary support systems in a 3-entry gate road system subjected to high horizontal movements. The support system used in several other coal mine operations, consisted of internal high-strength galvanized resin-grouted cable supports. The system virtually eliminates the necessity for external crib, timber, or concrete supports. The support system consisted of 2.4 m (8 ft) full-column resin grouted bolts and 4.8 m (16 ft) long cable supports installed in conjunction with wire mesh and "Monster-Mats." Cable loading and roof deformations were monitored to evaluate the behavior of the immediate and main roofs during first and second panel extractions. Additionally, cable trusses were installed on the longwall headgate to protect the coal conveyance system from roof and pillar falls created by the formation of cutters and gutters. The test results indicated that the designed support system successfully maintained the roof during the extraction of two longwall panels and dramatically reduced the cost of secondary support. This paper describes the theory of high-horizontal roof movements, the advantages of vertical cable supports and cable trusses, and presents the roof and cable measurements made to assess the support performance during longwall retreat mining.

Jan 1, 1996

By James E. Parkes

The Silver Spring Transit Center is a new three-level transit center that will include bus loops for County, Metro and intercity buses, parking, and retail space. It replaces an existing bus station and connects to a busy metro rail station in downtown Silver Spring, Maryland. Significant site constraints in both plan and profile had to be dealt with in developing a design for support of the structure. Over 90 rock-socketed drilled shafts ranging in size from 3 to 7 foot in diameter were ultimately used to accommodate the limited space and large column loads, and to adapt to the variable rock surface at the site. Site access during design was limited due to the existing active bus station, so contract documents were adapted to include further explorations. Differences in anticipated and actual field conditions regarding the depth, quality, and variability of the rock had to be overcome in construction. Osterberg Load Cell testing during construction allowed for verification and optimization of the shaft design. Additional issues dealt with on this constrained site in an urban setting included construction staging issues, such as working around specialty contractors for tieback walls, blasting operations for rock excavation, productions issues for hard bedrock, as well as coordination issues with third parties, most notably the Washington Metro Area Transit Authority. Aspects of the foundation design and optimization, preparation of the contract documents to deal with the complicated nature of the project, and lessons learned from construction are also discussed.

Jan 1, 2011

By J. E. Crawshaw

"The few previous observations of the effect of turbulence on limits of inflammability have been made on a small scale in turbulence produced either by a fan or by movement of the mixture.By a suitable amount of turbulence from a fan the lower limit of methane was 5 per cent as compared with 5 per cent observed for quiescent mixtures in the same vessel.3 With a streaming movement of the gas mixture within the range of speed from 35 to 65 centimeters per second (69 to 128 feet a minute) the lower limit was approximately 5 percent,4 For a quiescent mixture of ethane the lower limit was 3.10 per cent ethane, but with fan running at a moderate speed a 3 per cent mixture exploded.5The object of the tests herein reported was (1) to determine the lower limit of natural gas in a mixture of natural gas and air Which would be ignited and propagate violently when the turbulence was produced by explosives fired from a cannon into the mixture; (2) to observe the behavior when the mixture contained less than this low limit; and (3) to determine how turbulence produced by a fan affects thin limit.Four series of tests were run, three of which were to determine the effect of different sources of ignition: Tests with (1) an electric igniter; (2) 3F black blasting powder stemmed with 2 pounds of dry fire clay stemming used to ignite the mixture, and (3) 40 per cent straight nitroglycerin dynamite unstemmed. The fourth was made to study the effect of turbulence produced by a two-speed electric fan, using an electric igniter as the source of ignition.In both series of tests with explosives, charges of 50 and 200 were used to determine the effect of increased quantity of explosives on the lower limit of natural gas."

Jul 1, 1930

By D. Whittles, C. J. Lea, T. X. Ren, A. Kelsey

A methodology for the simulation of methane drainage combining geotechnical modelling and computational fluid dynamics (CFD) will be described. Geotechnical modelling was used to predict the development of stress and strain due to mining. The results from the geotechnical modelling were combined with empirical expressions for the variation in permeability with stress of coal measure rocks and assumptions on fracture behaviour. This allowed the permeability, as affected by mining, to be specified in CFD simulations. Flow of methane through strata, with and without methane drainage, was then simulated to examine the effects of methane drainage.

Jan 1, 2003