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By H. Verakis

A fire in a coal mine conveyor belt entry represent a major safety and health risk to miners. Fighting belt entry fires can be a commanding effort. If there is a failure of one aspect in the fire fighting needs such as a dissimilar hose-valve connection, then it can result in the inability to extinguish a fire. Fire incident data compiled over nearly 30 years for underground coal mines shows that fires in belt entries account for 15-20 percent of the total number of fires. Fires in the belt entries of coal mines have resulted in injuries and fatalities. New regulations have been promulgated that require an unplanned fire not extinguished within 10 minutes of discovery to be reported to the Mine Safety and Health Administration (MSHA). A fire that is not extinguished within several minutes may take hours or days to extinguish or may require sealing a section or the mine in some cases. The current fire protection regulations in the U.S. Code of Federal Regulations (CFR), Title 30, Part 75 are designed to prevent or control the fire hazards present in a belt entry. These requirements and other factors affecting belt entry fires are discussed, including fire detection and warning, fire suppression devices, type and location of fire fighting equipment, waterlines, and cleanup and removal of combustible materials. The fire suppression systems used to extinguish/control a belt fire and the effect of ventilation on the propagation of conveyor belt fires are also discussed.

Jan 1, 2009

Mineral exploration management has undergone major changes particularly in the last decade. Parallel to these changes in management, and partially responsible for them, have been the changes in governmental laws and regulations at both National and State levels reinforced by a highly competitive climate created by the exploration boom in Australia. The influence of overseas methods and approaches have been married to the Australian techniques resulting in a management climate which is not only familiar with the technical aspects of exploration, but is also familiar with the personnel, economic and legal phases associated with the expenditure of very large sums of money. The utilization of all the geosciences coupled with mathematical models and computer techniques for pre-selection and assessment of areas are now normal aids used in management decisions. Management techniques developed and being developed will ensure that successful exploration will be carried out if sufficient incentives are guaranteed.

Jan 1, 1974

By W. G. Whildin

This paper will be confined to a discussion of the methods in use in the property of the Lehigh Coal & Navigation Co. in the Panther Creek valley. Only the methods used in mining the Mammoth vein will be .considered, as the methods in use in the smaller veins are adaptations of the same. Typical cross-sections of the coal basin are shown in Figs. 1, 2, and 3. The Mammoth vein varies in thickness. It is 21 ft. at one colliery, 50 to 125 ft. at another, and over 200 ft. at still another. Its normal thickness is 35 to 40 ft. At some points in the Panther Creek basin the Mammoth vein is made up of three splits-the Bottom, Middle, and Top, while in other portions the dividing strata between the benches amount to only 1 ½ to 2 ½ ft., and the vein is practically in one. The section of the Mammoth vein shown in Fig. 4 was taken at the Greenwood colliery, and shows a thickness of 60 ft. The miners know it by benches, as follows:. The Three-Foot, the Four-Foot, the Eighteen-Inch Slate, the Bony, the Grey Slate, the Grain Clear, the Five-Foot, the Seven-Foot, the Slaty or Dirty benches, the Blue Slate, and the Top bench. The present-day methods of mining are an outgrowth of the experiences of the last 100 years in this territory. The first attempt at mining, according to the company's maps, was made at Summit Hill in 1792, when open cuts and pits were made. Later the pillar-and-breast method was introduced. This and other methods will be discussed hereinafter. Drifts, slopes, and shafts, according to the requirements and physical conditions, are the main openings, from which the gangways are driven. The gangways (haulageways) and airways are driven along the strike of the vein; the gangways in the various veins on the same level being connected by tunnels through the intervening rock. The gangways and airways in thick veins are heavily timbered ;throughout. The sets of timber, consisting of a collar and two legs, are spaced 5 ft. apart, and later, after the ground :has settled, additional sets, called "liners" or "relief sets," are placed between, to relieve the strain on the original timbers, so that the result is a set of timber every 2 ½ ft.

Jan 12, 1914

By Sharon K. Reamer, Klaus G. Hinzen, Brian W. Stump

"This study investigates seismic wave propagation from two production shots in a limestone quarry. Our motivation is to investigate the efficiency of two superpositioning techniques. The production shots consisted of an 18 and 20 hole explosive array detonated in a single row with constant delay times of 32 and 20 ms, respectively. A single shot was fired on a neighboring part of the quarry bench. The experiments were instrumented with 20 three component seismometers (35-120 m range). The computer-controlled electronic firing system resulted in firing time deviations of less than 1.4% of desired fired times. Linear superpositioning with the observed single shot data produces seismograms which adequately reproduce temporal effects of the multiple explosions; however, spatial effects due to the extended source length (68-76 m) are not modeled with this method. Linear superpositioning with individual half-space Green's functions for each explosion in thearray convolved with a calculated Mueller-Murphy source produces seismograms which match the time duration of the observed production shot seismograms and differ in absolute peak amplitude by less than a factor of three. Parameter estimation for the source is taken from chemical explosion study results. The single source model differs in amplitude from the observed single source seismograms by a factor of 2.3."

Jan 1, 1991

Washington has been the largest coal producing state of the Pacific Coast, and the only one producing coke commercially. With the exception of the few estimated figures, the tonnages in Table 71 are from Goodyear and other sources as shown. [ ]

Jan 1, 1942

By J Tibbett, F T. Suorineni, B Hebblewhite

Block caving is an important mining method for the future economic exploitation of large, low-grade, steeply dipping orebodies. While block caving is not a new method, there are still many unknowns surrounding the mechanics driving the process, particularly as we are forced into deeper, higher-stressed and stronger ore deposits. The caving industry is desperate to provide some explanation behind the myths of caving geomechanics to better predict and manage current caves and caves of the future. Large amounts of data are collected to help understand caving, but it is not fully utilised and current approaches for analysing the data are capacity limited. The application of virtual reality and scientific visualisation (VRSV) technology to visualise and analyse block caving is a critical future component in the assessment toolbox. VRSV enables large, complex, multidimensional data sets to be analysed and the power of human visual problem solving processes to be utilised. Block caving is a complex system and needs to be analysed as a system, rather than looking at individual factors one at a time. A software module has been developed at UNSW Australia for use in the advanced visualisation interactive environment for analysis of the block cave mining system (BCMS). This fully immersive, 3D virtual assessment tool shows exciting potential and is used to analyse the BCMS with a close linkage to time (ie the chronological occurrence of data). This tool will enable a true investigation into the cause and effect relations within the BCMS. Current research is investigating Newcrest Mining Limited’s Ridgeway Deeps operation and is aiming to turn some of the cause/effect relationships into increased geomechanics understanding to provide improvements to ground control management. This paper outlines the methods of assessment used to analyse BCMS geomechanics with VRSV and shows the potential of the software module for BCMS analysis.CITATION:Tibbett, J, Suorineni, F T and Hebblewhite, B, 2014. The application of virtual reality technology and scientific visualisation to the understanding of block cave mining systems, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 195–200 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By C. J. McHargue, J. C. Ogle

Lightly deformed columbiun single crystals which contained only parallel hoins or purullel and intersecting trains were annealed at 1000' and 1600"C. No re-crystallizntion occurred in specimens hawing only parallel twins. Only noncoherent twin boundaries nzipated at 1000°C but both coherent and noncoherent ones moved al 1600°C. Recrystallization occurred within a few minutes at twin intersections at 1000°C. The orientation 01 the recrystallized grains differed front that of both the matrix and deformation twins, but could he derired by (110) and/or(112) rotations. ALTHOUGH twinning in metals has been extensively studied, there have been no definitive studies of the annealing behavior of crystals containing deformation twins. Some effects observed after annealing deformation twins have been summarized by Cahn1 and Hall2. Any or all of these phenomena are observed: 1) The twins may contract so that the sharp edges of the lens become blunted, and eventually the twin may disappear entirely. 2) The twins may balloon out at an edge, giving rise to a large grain having the same orientation as the twin. 3) The specimen may recrystallize; i.e., new grains are nucleated and grow at the expense of the twins and the crystal immediately adjoining the twin. Such grains have orientations which are not present before. Contraction has been observed in iron,3 titanium,3, 4 beryllium,5 zinc,8, 7 Fe-A1 alloy,' and uranium.9 Long anneals at high temperatures are required to have any appreciable effect in these metals and only thin twins are absorbed. Lens-shaped twins are absorbed from the edges: the thin, almost parallel-sided twins are usually punctured in several places and each piece contracts independently. Absorption is very gradual and no sudden cooperative jumps have been observed. The expansion of a twin into a larger grain of identical orientation is unusual, but such growth has been observed in iron,"'" zinc,6 and uranium." Crystals which have been deformed simultaneously by slip and twinning recrystallize first in the area adjacent to the twin. New grains appear faster where the twins intersect: but isolated twins, especially if thick, can also give rise to new grains. This type of recrystallization occurs in zinc.6, 7, 12, 13 and beryllium.14 Reed-Hill noted, in a single crystal of magnesium, the nucleation of a recrystallized grain at a twin intersection which had the same orientation as the second-order twin and which grew into the highly strained matrix.15 Short-time annealing has been reported to cause no change in the deformation twins in vanadium,16 columbium, 17, 18 tantalum,19 tungsten,'' and zinc.7 The purpose of this investigation was to note the effects of annealing on the coherent and noncoherent boundaries of deformation twins in columbium and to locate the nucleating sites for recrystallization. The orientation relationships, which the new recrystallized grains have with the parent crystal and the deformation twins, were also determined. EXPERIMENTAL PROCEDURE Single crystals of columbium were obtained by cutting large grains from electron-beam-melted buttons which contained 10 to 50 ppm C, 10 to 100 ppm O,, 1 to 10 ppm H2, and 10 to 15 ppm N2. The crystals were hand-ground and chemically polished until all grain boundaries were removed. The specimens were mounted in an epoxy resin and a face of each crystal was mechanically polished on a Syntron polisher using Linde A and then Linde B polishing compounds. After all faces were mechanically polished, the crystal was electrolytically polished to remove all distortion due to cutting and grinding. Laue photographs were taken of all faces of the crystals to determine the quality and orientation of each crystal. The crystals were compressed about 10 pct at -196 C in a specially constructed compression cage with an Instron tensile machine. Each crystal was separated from the top and bottom anvils by teflon films which acted as a lubricant. With the specimen crystal in position, the entire cage was cooled to -196°C by being submerged in a Dewar containing liquid nitrogen. The crystals were compressed at a rate of 0.02 in. per min and the load was recorded on a strip-chart recorder. After deformation the crystals were mechanically polished on 600-grit paper and Pellon cloth with Linde A and Linde B polishing compounds. The crystal faces were chemically polished and then etched. The twin planes were identified metallographically from an analysis of the twin traces on two surfaces. Annealing was carried out by placing each crystal in a columbium bucket made from the same electron-beam-melted material as the crystal itself and suspending the bucket by a tantalum wire in a quartz tube. After a vacuum of 10-7 Torr was attained, a furnace at 1000" or 1600 C was raised into position and the crystals held for various lengths of time. The crystals were repolished and etched after annealing to remove any surface contamination. Approximately 0.010 in. was removed during this process. The resulting surface was examined metallographically for microstructural changes due to annealing. A microbeam Laue camera mounted on a Hilger Micro-focus X-ray unit was used to determine the Orientstions of the recrystallized grains. This X-ray micro-beam camera had a 0.002-in.-diam collimator and incorporated the ideas of both and and chisWik21 and Cahn.22

Jan 1, 1967

By Terry S. Cory

This report covers antenna design, analysis, and development work suited for use with a wireless radio communication system operating at medium frequency. The work includes the test and evaluation of prototype vehicular antennas developed during the program.

Jan 12, 1978

By T. E. Newkirk

In the past few years there has been considerable controversy on the most suitable material to be used in ventilation doors which will have to serve also as fire doors. For this reason it was thought useful at Mclntyre to find out to what extent our zinc chloride treated spruce doors were fire resistant and what protection we could expect in case of an underground fire. The doors to be tested were constructed of the same material as that used in our regular ventilation doors underground, namely, 2-inch tongue-and-groove well seasoned spuce. It is to be noted, however, that whereas the dimensions of the ventilation doors are 5 ft. by 6 ft., those of the test doors were only 14 in. by 17½ in. The treated doors were made up from lumber that l1ad been treated with chromated zinc chloride, as described in Mr. Keeley's paper. Two kinds of tests were carried out: a heat test and a flame test. An electric muffle furnace for assaying, equipped with a pyrometer, was used for the beat test, the furnace door being replaced by the wooden door to be tested. In the flame test, the door to be tested formed one end of a rectangular steel box in which was placed a large blow-torch. Air was admitted at the rear of the box. A pyrometer recorded the temperature at the inside surface of the door where flame impinged. The results of the tests are presented in the accompanying table, in which the word 'failed' is to be interpreted as meaning that the door had been damaged to the extent that smoke, but not necessarily flame, issued from its outside surface.

Jan 1, 1949

By William D. Gallant

This paper describes a joint cooperative project between the CANMET Cape Breton Coal Research Laboratory and the Cape Breton Development Corporation to conduct a trial of split set cable slings for remedial support in longwall gateroads. Slings were installed in two test sections of the 2 West panel, Phalen Mine which exhibited deformation and the potential for excessive deterioration when subjected to the front abutment of the wallface. Roadway support behaviour was monitored at the trial sites, including lengths of roadway with the standard support of steel sets without remedial support. Observations were made on convergence, loading of the steel supports, loading of the slings, and wallface performance. Comparisons are made of the results obtained from the areas with remedial support to that without, which demonstrates that the slings provided effective remedial support limiting further deterioration of the roof. Improved face end conditions have contributed to increases in safety and productivity of the longwall panel.

Jan 1, 1990

By Fraser C. J

The township of Yalloum was established in 1921 to provide accommodation for the work force on the sites of the power station and open cut which were to become the basis of Victoria's electricity industry.A company town, Yallourn flourished, and in its heyday in the 1950s the township had a population in excess of 5500 residents.However the town was sited over a valuable coal field. In the 1960s, studies conducted by the State Electricity Commission indicated that excavation of this coal as a continuing development of Yalloum Open Cut was the optimum choice to meet the growing energy needs of Victoria. Operation in what became known as the Township Field commenced in 1979 and the completion of the overburden stripping was successfully achieved on target in 1991.

Jan 1, 1992

By John F. Schat, T. William Thompson

Laboratory data on the time-dependent compaction of porous rocks are presented, and various attempts to model this behavior are described. These lead to a discussion of the problems that arise in using laboratory data to estimate long-term effects. A method is suggested for combining laboratory data with information from the geologic record to estimate long term effects.

Jan 1, 1986

SAMUEL T. HOYT,? Minneapolis, Minn. (written discussion||).-The subject of grain inheritance in iron and steel is apparently one which can he considered from the point of view of the two laws governing the rate of formation of crystal nuclei and the linear velocity of crystallization, which have been investigated by Tammann and collaborators, and of the additional law of coalescence. According to the work of Tammann, both the nuclei number, which is taken to be the number of crystal nuclei to form per unit volume per unit time, and the linear velocity of crystalli-

Jan 5, 1918

By Walter E. Mingramm

The construction of rescue-apparatus on the principle of furnishing the wearer with air from a tank containing it under high pressure was given up by inventors about 20 years ago. Such an apparatus must supply continuously, for not less than two hours, nearly 50 liters of pure air at atmospheric pressure per minute, or a total of 6,000 liters (210 cu. ft.); and a cylinder containing this amount of air, under 2,000 lb. pressure, would weigh 180 lb. or more. Although apparatus has been recently constructed utilizing liquefied air, no experiments have been made to determine the regularity with which the air is generated, nor has its chemical composition been determined. Moreover, the chief objection to such an apparatus is the difficulty and cost of keeping on hand a large quantity of liquefied air. The system of furnishing the wearer of a breathing-apparatus with air which has given the best results, and has found

Jan 1, 1909

By Mauro Giraldo Paredez

"El presente texto determina la capacidad de carga de las toneladas que puede soportar cada pie de anclaje de los distintos pernos, así como el comportamiento de sostenimiento de perno al variar su significado. En el caso de los Split Set y barras helicoidales,se solicitó a los proveedores que los cortaran en longitudes apropiadas para que, al instalarlos, hagan los anclajes efectivos antes indicados. En el caso de los Swellex e Hydrabolt, que son pernos de expansión, se tuvo que acondicionarlos utilizando tubos de estrangulamiento y otros materiales."

Jun 1, 2012

By Fidel T. Torres

El presente texto describe las pruebas con sistema de iniciación electrónica eDev, realizadas en Compañía Minera Suyamarca – Unidad Pallancata del Grupo Hochschild, las cuales se se desarrollaron durante los meses agosto 2010y enero 2011. Asimismo, los test fueron direccionados a realizar voladuras a frente completa y utilizando el sistema mixto con el actual sistema de iniciación que utilizaba la minera. Las ventajas que ofrece el sistema mix son: la disminuación en el sobrequiebre demostrado en el resultado de las áreas en el ByPass1400, el aumento del número de cañas y la disminución de la fragmentación.

Sep 12, 2011

By L. Larson

Rock samples were taken, away from zones of mineralization , from seven sections of five rhyolitic zones as define d by Spence (l967) in the Noranda area. The purpose of the investigation was to test whether there were intrinsic differences between the zones which would differentiate between non-productive zones and productive zones. For the elements sought (major elements, Cu , Pb , Zn and S) , no clear chemical difference between the zones was found. Thus, identification of a favour able zone from the over -all composition of the zone does not appear promising. Within sampled sections, there is no clear gradual compositional change up through the sections. A capping of highly siliceous massive rhyolite is present in five of the sections sampled. A layer of relatively basic material occurs near the base of individual units. The third (mine zone) and later zones contain abundant pyroclastic material, where as the non-productive zones do not.

Jan 1, 1977

By T. Klemetti

Moisture deterioration of clay-rich roof rocks causes high numbers of roof falls in coal mines in humid summer months. Rocks with high moisture content are generally weaker and can further deteriorate when subjected to wetting and drying cycles. As a result, it is important to evaluate the moisture-sensitivity of roof rock prior to mining. The National Institute for Occupational Safety and Health (NIOSH) has evaluated three moisture-sensitivity index tests on roof rocks from 23 U.S. coal mines. The three tests were the University of Kentucky Weatherability test (Weatherability test), the Consol Energy Water Sensitivity test (Water Sensitivity test), and the NIOSH Immersion test (Immersion test). Of these three tests, the Weatherability and Water Sensitivity tests are more reliable in classifying the moisture-sensitivity of roof rocks. Disclaimer: The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.

Jan 1, 2009

By H. J. Chalmers

THE H.B. MINE and concentrator are located in the Nelson Mining Division of British Columbia, on the north side of the Sheep Creek valley about seven miles southeast of the town of Salmo. It is an operation of The Consolidated Mining and Smelting Company of Canada, Limited (Cominco), which has its metallurgical plants at Trail, about 25 miles west. The property was originally staked about 1907 by Horton and Benson, whose names are commemorated in the designation "H. B." Up until 1927, a considerable amount of development work was done in the upper levels by various companies. Cominco purchased the ?property in 1927 and carried out intermittent work until 1946. Following this, an extensive surface diamond drilling programme and a subsequent underground exploration were undertaken. Sufficient ore was outlined 'to warrant the construction of a 1,000: ton concentrator. This was started in April, 1952, and completed by the spring of 1953. However, because of adverse base metal market conditions, operation was deferred until May, 1955.

Jan 1, 1957

By Robert B. Fulton, Gill Montgomery

Fluorspar is the commercial name for fluorite, a mineral that is calcium fluoride, CaF2. The name, derived from the Latin word fluere (to flow), refers to its low melting point and its early use in metallurgy as a flux. It is the principal industrial source of the element fluorine. Two other minerals, cryolite and fluorapatite, have significant fluorine content. Cryolite, sodium aluminum fluoride, Na3AlF,, is a rare mineral that has been found in commercial quantities only in Greenland. The natural material has been supplanted by synthetic cryolite for its principal industrial use in the manufacture of aluminum. Fluorapatite, Ca5F(PO3)2, is a source of phosphate for fertilizer manufacture, containing a small percentage of fluorine. Commercially mined deposits of apatite have varying amounts of fluorine, chlorine, hydroxyl, and carbonate. HISTORY Fluorspar was used by the early Greeks and Romans for ornamental purposes as vases, drinking cups, and table tops. Various peoples, including the Chinese and the American Indians, carved ornaments and figurines from large crystals. Its usefulness as a flux was known to Agricola in 16th century Europe. Fluorspar mining began in England about 1775 and at various places in the United States between 1820 and 1840. Production grew substantially following the development of basic open hearth steelmaking, wherein it is used as a flux. Use was stimulated by growth of the steel, aluminum, chemical, and ceramic industries, particularly during World Wars I and 11. Fluorocarbons entered the picture in 1931. The use of anhydrous hydrogen fluoride (HF) as a catalyst in the manufacture of alkylate for high octane fuel began in 1942. Differential flotation for separating fluorspar from galena, sphalerite, and common gangue minerals in the 1930s and the application of heavy media concentrating methods to the treatment of low grade ores in the 1940s were outstanding technological advances that facilitated increased production. Pelletizing and briquetting of flotation concentrates for use in steel furnaces and the development of flotation schemes for beneficiating ores containing abundant dolomite and barite have been major improvements in the industry. USES OF FLUORITE Fluorspar is used to make hydrogen fluoride (HF), also called hydrofluoric acid, an intermediate for fluorocarbons, aluminum fluoride, and synthetic cryolite. It is used as a flux in the steel and ceramic industries, in iron foundry and ferroalloy practice, and has many minor specialized uses. Hydrogen fluoride is produced by reacting acid grade (97% CaF,) fluorspar with sulfuric acid in a heated kiln or retort to produce HF gas and calcium sulfate. After purification by scrubbing, condensing, and distillation; the HF is marketed as anhydrous HF, a colorless fuming liquid, or it may be absorbed in water to form the aqueous acid, usually 70% HF. Synthetic cryolite, organic and inorganic fluoride chemicals, and elemental fluorine are made from hydrofluoric acid. The acid itself is important in catalysis in the manufacture of alkylate, an ingredient in high-octane fuel for aircraft and automobiles; in steel pickling, enamel stripping, and glass etching and polishing; and in various electroplating operations. The manufacture of one ton of virgin aluminum requires about 12 to 29 kg of fluorine content in synthetic cryolite and aluminum fluoride. This quantity, through improved technology and recovery practices, is being lowered significantly in countries with the most advanced technology (i.e., Australia and Sweden), while others (i.e., Surinam and South Africa), remain at the high end. Elemental fluorine is prepared from anhydrous hydrofluoric acid by electrolysis. Gaseous at room temperature and pressure, fluorine is compressed to a liquid for shipment in cylinders or in tank trucks. Elemental fluorine is used to make uranium hexafluoride, sulfur hexafluoride, and halogen fluorides. Gaseous uranium hexafluoride is used in separating U235 from U233 by the diffusion process. Sulfur hexafluoride is a stable high dielectric gas used in coaxial cables, transformers, and radar wave guides. Halogen fluorides have important applications, mostly as substitutes for elemental fluorine, which is more difficult to handle. Emulsified perfluorochemicals, organic compounds in which all hydrogen atoms have been replaced by fluorine, are undergoing investigation as promising blood substitutes. They transport oxygen and, in conjunction with a simulated blood serum, perform many functions of whole blood. With further development, these organic compounds may ultimately, in emergencies, be useful in saving lives of animals and humans during periods of acute shortages of natural blood. Inorganic fluorides are used as insecticides, preservatives, antiseptics, ceramic additives, and fluxes and in electroplating solutions, antioxidants, and many other products. Boron trifluoride is an important catalyst. Organic fluorides are volume leaders in the fluorine chemical industry. Fluorinated chlorocarbons and fluorocarbons are prepared by the interaction of anhydrous HF with chloroform, perchlorethylene and carbon tetrachloride, and are characterized by low toxicity and notable chemical stability. They perform outstandingly as refrigerants, aerosol propellants, solvents, and cleaning agents and as intermediates for polymers such as fluorocarbon resins and elastomers. Fluorocarbon resins are inert compounds that have unusually low coefficients of friction and have found a number of applications as lubricants for parts that cannot be oiled, e.g., bearings for window raising equipment located inside of automobile doors, in small electronic equipment, for the manufacture of chem-

Jan 1, 1994