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By H. P. Greenwald, H. C. Howarth

The rapidly increasing use in coal mines of portable auxiliary fans, which are generally 'blowers" employed in connection with canvas tubing, raises questions concerning the hazards of such equipment, especially where the practices are opposed to established methods of ventilating face workings. Half a dozen or more coal-mine explosions and some fires have been attributed to the use of auxiliary fans; moreover, competent mining engineers have found many dangerous installations and methods of use-for example, intermittent running of the fans in gassy mines with consequent accumulations of firedamp at the faces. These facts have led the U. S. Bureau of Mines to issue this recommendation: "In the interest of safety, the Bureau of Mines, Department of Commerce, recommends that auxiliary fans or blowers should not be used in coal mines as a substitute for methods of regular and continuous coursing of the air to every face in the mine." The comparatively recent introduction of new types of mining machines, mechanical loaders, face conveyors, and slabbing machines has encouraged the trial of new systems of face mining, all of which have for their object the rapid advance of the faces. Although the latter has certain economic advantages, in gassy mines the rate at which gas is given off is generally found to increase in proportion to the speed of advance into new territory, which in turn increases the difficulties of efficient ventilation of the face workings. Some of the systems of advance mining being tried in connection with new mechanizing methods practically compel the use of blower fans and tubing, as single narrow places arc now driven 300 ft. or more without crosscuts. In some instances a series of parallel headings are driven without crosscuts pre-

Jan 1, 1928

By Charles White Merrill, James W. Pennington

No metallurgical process developed in the 20th century compares with froth flotation in its effect on the mineral industry. Processes like gravity - concentration, amalgamation, and pyrometallurgical reduction are of ancient origin; others like cyanidation and electrolytic reduction were well established by 1900. Such metallurgical processes as heavy-media separation, ion-exchange, and solvent extraction belong to this century, but their influence is small compared with froth flotation. Data collected by the U. S. Bureau of Mines* in a canvass of 202 froth flotation plants reveal that, in 1960, 198- million tons of material was treated to recover 20-million tons of concentrates which contained approximately $1 billion in recoverable products. SIGNIFICANCE OF FLOTATION Froth flotation as described in this chapter refers to a wet process for separating properly ground mineral particles into two or more products. It involves the separation of mineral particles from each other in a liquid pulp by means of air bubbles. Finely crushed ore is agitated in water with the addition of air or other gases. Various chemicals and oils are added to cause the selected mineral particles to attach themselves to the air or gas bubbles. These bubbles, carrying the mineral particles, rise to the surface where they are removed in a froth, while the other particles remain suspended in the pulp. The earliest flotation divided the raw material into two products: a bulk concentrate that was removed as a froth and a tailing that remained in the flotation machine. The froth usually contained the valuable constituents. The successful application of such a process depended on the recovery of a single concentrate from which one or more valuable constituents could be recovered by a chemical or smelting process. With the advance of the art, however, the principle of selective flotation, by which two or more relatively pure products could be recovered from complex raw materials, was evolved. Other chapters in this volume describe the developments during the last 50

Jan 1, 1962

By Donald M. Podobnik

The Cuajone Concentrator of the Southern Peru Copper Corporation is located approximately 900 kilometers southeast of Lima, Peru, near the 500 year old town of Moquegua, in an area that has been occupied since antiquity. Since the plant was started in July, 1976, the throughput has steadily increased from 36,000 to 46,000 metric tons per day. The widely distributed molybdenite content of the ore body ranges from 0.02 to 0.04% MoS2. The molybdenite content of the copper concentrate has always been sufficient to justify operation of a byproduct molybdenite plant. During the first nine months of 1980, the average grade of the ore was 1.169% copper and 0.026% molybdenite.

Jan 1, 1981

By Lewis. Clifford J.

The purpose of this article is to present design information and operating data on a pilot gas scrubber which is believed to be a new approach for removing noxious gases and particulate matter from the off gases of coal burning power plants and smelters. This principle of scrubbing gases, particularly, scrubbing with an aqueous slurry of lime, was conceived by the author early in 1972. The National Lime Association financed the design, fabrication and initial operation of the unit. The unit was fabricated by Hazen Research Inc. of Golden, Colorado. It has been tested on the off gases of two coal burning power plants and one smelter. The current environmental program has stimulated research and development activity directed toward the removal of sulfur oxides, oxides of nitrogen, particulate matter and other undesirable substances from gases discharged into the atmosphere. At present, most of this effort is focused on the removal of sulfur dioxide and particulate matter by aqueous scrubbing of the gases. This presentation deals particularly with the removal of sulfur dioxide using an aqueous slurry of lime as the scrubbing medium. In recent papers, the author has called attention to-the sludge problems resulting from aqueous scrubbing and to some earlier data on the pilot scrubber about to be discussed.1/

Jan 1, 1973

By J. B. Rubinstein

"The paper gives an overview of the history of flotation machine development. The laws of their evolution are stated and the place and role of column flotation are demonstrated.The major parameters of column cell diameter and height are discussed. Options are proposed for optimization of the hydrodynamic characteristics of large-capacity column cells. The high efficiency of columns with cell height of 4-6 m is demonstrated. The optimum parameters of multisectional column machines are determined. Their advantages compared to monocells are shown. A scaling-up procedure for column machines was developed based on flotation macro- and microhydrodynamics simulation."

Jan 1, 2003

By N. S. Dalal, B. Jafari, F. H. Y. Green, M. Petersen, V. Vallyathan

"Stable coal radicals (SCRs) were detected by electron spin resonance (ESR) spectroscopy in the lung tissue of autopsied coal miners. The SCR concentrations were measured in the lung tissues from 98 coal miners with and without (a) coal workers' pneumoconiosis (CWP), (b) cancer, and (c) a history of cigarette smoking. Concentrations of SCRs were also determined in the lungs of nonminer controls. The SCR concentration was related to longer mining tenure, CWP disease severity, lung cancer, and cigarette smoking. The mean concentration of SCRs in the lung tissues of miners with 30 ± 1.4 y of coal mining exposure was 5.3 ± 1.3 x 10"" spins/g versus controls who had a nondetec¬table level (< 10 15 spins/g). An increase in disease severity was accompanied by a progressive increase in SCR concentration. A SCR concentration of 4.8 ± 0.7 x 10"" spins/g was found for simple CWP (with moderate coal macules) versus 7.8 ± 4.6 spins/g lung tissue for complicated CWP (with progressive massive fibrosis). Significantly higher (i.e., 10 x 10"") concentrations of SCR in the coal miners' lung tissues were associated with an exposure history in the anthracite regions of northeastern Pennsylvania. These results in¬dicate a possible role for SCRs in the disease process. Furthermore, ESR appears to be an adequate methodology for the quantitation of coal dust retained in the lung and for distinguishing exposures to anthracite and/or bituminous coal.THE PREVALENCE AND SEVERITY of coal workers' pneumoconiosis (CWP) differ markedly between geographic locations, mines, and coal fields irrespective of comparable levels of exposure to coal mine dust These differences cannot be fully explained by the presence of silica and other minerals in the coal mine dust.' Rank of coal is also an important factor in the pathogenesis of CWP. Equally important is that the prevalence of CWP decreases from east to west in the United States,' and South Wales miners develop more severe CWP than miners in Scotland.' However, there are conflicting reports that cast uncertainty on the influence of rank of coal in the development of CWP."" These problems are complicated but will be solved as new technology emerges and as more is learned about the disease process."

Mar 1, 1992

By I. J. Hegyi, J. J. Tietjen, H. Nelson, J. I. Pankove

The fabrication of p-n junctions in GaAsl-,P, alloys by a vapor-phase gowth technique has for the first tirne resulted in room-temperature injection lasers capable of operating over a broad range of wavelengths extending into the visible region of the spectrum. The shortest wavelength achieved to date is 6750A at room tetnperature. In addition, at 78°K the threshold current density values for these lasers are generally the lo~vest reported, and the emitted radiation extends to the lozc,est wavelength ever attained (6350A). With lasers fabricated from material containing 14 pct Gap, quanticm efficiencies of 26 pct and peak power outputs of 25 zu were obtained at room temperature. ALTHOUGH room-temperature operation of GaAs injection lasers has been well-documented,&apos;-5 the operation of GaAsl-,P, (x > 0) laser diodes has been restricted to relatively low temperatures.8-&apos;0 This has been previously attributed5, 7, 10-12 partially to the difficulty of preparing single-crystalline GaAsl-& alloys having a high degree of chemical homogeneity and purity. Also, with these materials it has been difficult to prepare high-quality, abrupt p-12 junctions by diffusion techniques; and, in turn, this has made it difficult to obtain optimum electrical properties for room-temperature operationL3 in the resulting laser diodes. As a result, GaAsl-,P, laser diodes have not been efficient enough to permit operation at room temperature. For example, using diffused structures, only a few diodes were obtained which could be operated even close to room temperature (255K)." Recently, a vapor-phase growth method of preparing epitaxial deposits of GaAsl - .P, alloys has been described,14 and the high-purity and homogeneity of these materials has been previously demonstrated. Of special significance, with this technique, n- or p -type doping can be initiated or discontinued at any time and at almost any rate during the crystal growth so that the donor and the acceptor concentrations can be easily controlled to obtain desired impurity profiles. This permits high-quality, abrupt p-TZ junctions to be vapor-phase grown entirely during the crystal growth process, so that diffusion or other p-n junction fabrication processes are unnecessary. After growth, the device does not have to be heated to elevated temperatures, which avoids the possible unwanted introduction and motion of both impurities and lattice defects. Using the vapor-phase growth method cited above, over 300 room-temperature injection lasers have been prepared from GaAsl-,P, alloys having compositions in the range of 0 5 x 5 0.41. These lasers have emitted cohe~ent radiation in the spectral range of 8350 to 6350A at 78°K or from 9000 to 6750A at room temperature. The threshold current densities of the best lasers are independent of the alloy composition over the range 0 < x < 0.2 and compare favorably with values for good GaAs lasers.&apos; MATERIAL PREPARATION Multilayer, epitaxial deposits of GaAsl-,P, alloys are prepared by a vapor-growth technique described elsewhere.14 With this technique, the individual layers which comprise the multilayer structure are prepared sequentially in the deposition apparatus without interrupting the crystal growth. The epitaxial layers are deposited on GaAs substrate surfaces oriented normal to the ( 100) direction. The substrate wafers employed in this study were usually doped with tellurium to an electron concentration of approximately 2 x 10" per cu cm. To avoid strains, the first 10 to 15 p of the deposited material is uniformly graded from pure GaAs to the specific GaAsl- ,P, alloy composition of interest. The GaAsl - ,P, alloy growth is then continued to form a layer of constant composition having a thickness in the range of 25 to 75 p. Both the graded region and the layer of constant composition are doped with selenium to an electron concentration of about 2 x 10" per cu cm. The p region of the diode is then incorporated in the crystal by abruptly changing the dopant concentrations in the vapor phase to facilitate doping with zinc. This layer has a hole concentration of approximately 3 X 1019 per cu cm and typically is 50 p thick. DEVICE FABRICATION In general, the GaAs substrate and the region of graded composition are removed. Ohmic contacts are made to the n-type side by tin evaporation and to the p-type side by an electrodeless nickel deposition. This is followed by an electrodeless deposition of gold on both sides. The crystal wafer is then cleaved along (110) planes and sawed into rectangular parallelepipeds. Typical dimensions are 100 by 300 for the junction area and 100 µ for the diode height. The diodes are either soldered to a copper stud or pressure-mounted in a copper clip. RESULTS AND DISCUSSION Approximately 400 laser diodes having compositions in the range of 0.41 have been prepared by the method described above. Each laser was routinely tested at liquid-nitrogen temperature. The lasers were operated with l-psec current pulses at a repetition rate of 60 pulses per sec. The parameters of greatest practical interest are the photon energy or wavelength of the laser output and the threshold current density. Fig. 1 shows the variation of photon energy with alloy composition at 78°K. The composition was determined from the lattice constant of the material obtained by X-ray back-reflection measurements. Although there

Jan 1, 1968

By J Furtney, W Fu, D Nutakor, A Brose

Rock blasting outcomes are often a shared responsibility of both the mine operations group and the mine geotechnical group. From an operational logistics and planning perspective, blasting concerns include optimal fragmentation for subsequent crushing, ensuring the blast is energetic enough to allow easy digging, and understanding the effect of muck from a previous blast on the current blast. From a geotechnical perspective, wall damage and catch bench capacity are the primary concerns. Other concerns for both teams include damage to mine infrastructure by fly rock or blast-induced vibrations, and the stability of open stopes under the pit. This work presents two blast modelling applications (or ‘apps’). The basic app instantly gives fragmentation and wall damage predictions for a given generic blast design. The advanced app loads the current pit contours, reads the blast design from a spreadsheet, and calculates the expected vibration magnitude and peak frequency. The apps have been developed specifically for the Rio Tinto Borates and Lithium Mine in California and are used to support blast design between the operations group and geotechnical group. The basic app instantly gives fragmentation and vibration predictions given a blast design by combining the Kuz-Ram fragmentation model with the scaled distance model for vibrations. The advanced app uses the signature hole method. Blasting outcomes at the mine have improved since using the apps.

Jun 22, 2022

The zinc-lead lode at Rosebery, on the West coast of Tasmania, has a total length of over 4000 ft. It consists of five elongated lenses parallel to the foliation planes of the quartz sericite schist, and is situated at the junction of the quartz sericite schist and a thin belt of slate. The lenses consist of massive, fine grained sulphide ore, with small amounts of quartz, barite, sericite and chlorite, and they terminate in masses of low grade ore. The gangue minerals increase in quantity in the low grade ore which includes small quantities of the manganese garnet, spessartite. The schist walls of the lenses are in places impregnated with lode minerals to a degree sufficient to permit them to be regarded as economic ore.The ore-bodies have developed from incoming mineral solutions by the replacement of the quartz sericite schist and are localised where the ore solutions have been confined by a relatively impervious slate band. The early stages of replacement of the schists are signified by the development of pyritic bands which are succeeded by a strong development of zinc blende. With ptogressive crystallisation, the character of the mineral solutions gradually changed and the development of galena, and its associated bournonite, became more important in the later stages.Remnants of the replaced schist, in the form of isolated wisps and schlieren of sericite and chlorite, are present in the ore body, more noticeably in the pyritic specimens. An important feature of the ore is the association of small ogllantities of gold with trahedrite.

Jan 1, 1934

By E. L. Burwell

Preliminary results of an in situ oil shale retorting experiment conducted by the Bureau of Mines in a shallow bed of Green River oil shale at Rock Springs, Sweetwater County, Wyo., are described. Eleven wells were drilled into a 20-ft-thick section of the shale lying between 68 and 88 It deep, and attempts were made to connect the wells through the shale with a fracture system created by application of high-voltage electricity (electro-linking), hydraulic fracturing, and explosive fracturing. Ignition of the shale through the central well was easily achieved with a propane burner, and shale oil began to collect in three wells within 3 hours. Propane injection was discontinued after 7 days, and combustion continues, although attempts to control the direction of the combustion front have been unsuccessful. Production rates as high as 4 ½ barrels of nil per day have been recorded, but too little is known about underground conditions to permit an estimate of recovery efficiency at this time.

Jan 1, 1969

By A. Butler

This paper explains the politics of mine nationalization in contemporary South Africa. Nationalization and privatization typically occur in the oil, mineral resources, and state utilities sectors, and they tend to follow one another in a long-term cyclical pattern. The paper explains why the current international environment has encouraged demands for nationalization and other forms of ?resource nationalism? in the South African minerals sector. It goes on to describe how the resurgence of resource nationalism has been influenced by internal factional politics in the African National Congress. It concludes that nationalization is unlikely to be the outcome of current policy deliberations within the ANC.

Jan 1, 2013

By C. S. Smith

The solubility of tantalum at 1100°C is 0.025 pct in pure copper, 1.2 pct with 20 pct Ni, and 2.7 pct with -30 pct Ni. The solubility decreases with temperature, and the alloys are precipitation hardenable. A 79/20/1 Cu-Ni-Ta alloy reaches maximum hardness after aging at about 750°C and, if cold worked, does not recrystal-lize below that temperature. The alloys have good tensile properties at moderately elevated temperatures and, since they can be hot and cold worked nearly as easily as cupronickel, they are suggested for service at temperatures above the usual limits for copper alloys. MASSIVE tantalum dissolves extremely slowly in copper-rich alloys, and tantalum powder forms refractory surface layers which prevent its solution unless special precautions are taken. After many trials, an 80 pit recovery was consistently obtained by using a mixture of a finely divided tantalum powder with two or three times its volume of potassium tantalum fluoride (K2TaF1,-melting point about 750°C) poured in a slow stream directly on to the surface of the molten copper alloy, so that each particle would remain coated with flux and be immediately and individually wetted by the molten metal. A 50-50 nickel-tantalum alloy has a melting point of about 1400°C and small lumps of it slowly but satisfactorily dissolve in molten copper-nickel alloys as does commerical "ferro-tantalum." The high affinity of tantalum for carbon makes it necessary to avoid carbonaceous crucibles. COPPER-TANTALUM ALLOYS Castings with good shrinkage resulted when 0.1 pct Ta or more was added to copper melted under charcoal and cast in air. Copper in two-pound melts to which 0.1, 0.15, and 0.2 pct Ta had been added retained residual amounts, by analysis, of 0.025, 0.023 and 0.026 pct, respectively. The solubility of tantalum in molten copper at about 1200 °C is therefore about 0.025 pct. The electrical conductivity of these three samples was 100.48, 100.00 and 100.20 pct IACS in the annealed condition, and 98.24, 97.98 and 98.08 in the cold-drawn condition. Wires 0.080 in. in diam withstood from thirteen to nineteen reversed bends after annealing for 30 min in hydrogen at 850°C and the metal was therefore completely deoxidized. The annealing temperature corresponding to 50 pct loss of work hardness in 1 hr in a strip cold rolled 77 pct reduction was 175C, compared to 230°C for equivalent undeoxidized material. It is unusual for a decrease of recrystallization temperature to result from an alloying addition, and the tantalum probably combines with and removes some minor impurity in the original copper that restrained its recrystalliza- tion. No difficulty whatever was encountered in hot or cold rolling or drawing these ingots, and were tantalum not so expensive it would make an excellent deoxidizer for copper. COPPER-NIcKEL-TANTALUM ALLOYS Studies were made of the solubility of tantalum in a large number of copper-rich alloys, but of these significant solubilities were found only in the case of an iron alloy (which, however, separated into two immiscible liquid layers) and alloys of copper and nickel, in which tantalum is freely soluble and which were found to have interesting properties. The latter alloys are the subject of U. S. Patent No. 2,430,306 (1947). They are not at present available commercially. The Ternary Constitution Diagram—The copper-rich corner of the constitution diagram was constructed on the basis of microscopic examination of samples of various composition and treatments. The alloys were hot rolled to 0.25 in. from castings 0.625 in. thick, then annealed for 1 hr at 1000°C, quenched, cold rolled to 0.10 in. and finally annealed for various periods of time at temperatures between 800" and 1100°C in a nonoxidizing atmosphere and quenched. When the solid-solubility limit had been transgressed, particles of a compound believed to be Ni2Ta*were

Jan 1, 1960

By Jonathan M. Pachter

Introduction The Bailey mining complex is located in Greene County, PA, in the Talley Run valley. It includes two Pittsburgh No. 8 seam deep mines (Bailey and Bailey No. 2), a coal preparation plant, and two refuse areas. Clean coal is shipped from the complex by way of a 24-km (15-mile) rail spur. It con¬nects to the Monongahela Railroad in Waynesburg, PA. In early 1981, Consolidation Coal Co. (Consol) began a permitting effort aimed at building the mine. Construction began in Dec. 1981, less than six months after the first application submittal. Clean coal was produced by the Bailey preparation plant in Sept. 1984. Several factors allowed quick permitting at Bailey. Effective project planning, including early formulation of a project planning team, and identification of red flag issues helped. So did innovative responses to environmental questions, and development of environmentally sound project designs. Forming a project planning team Consol management decided that Bailey mine construction had to begin in late 1981. A project permitting team was immediately formed to see that this goal was achieved. Team members included a project manager and personnel from Consol&apos;s engineering, environmental, and operating departments. Communications among all team members was crucial in obtaining the various state and Federal environmental permits. All project permitting team members participated in weekly meetings during application preparation. Discussions at these meetings ranged from recent public contacts, to application content, to environmental design considerations. Establishing a project manager was critical to the team&apos;s success. The project manager was responsible for seeing that permit acquisition, facility construction, and operation of the mining complex proceeded on schedule. The project manager had the final word, mediated disagreements, and frequently served as project spokesman to the public. Identifying red flag issues Red flag issues are those environmental factors with the most potential for delaying the schedule or stopping the project. The first red flag issue identified was organized local opposition. This opposition had completely derailed a US Soil Conservation Service proposal to build a multipurpose dam on Enlow Fork, a short distance

Jan 9, 1985

By AIME AIME

A SPECIAL meeting arranged by the Petroleum and Gas Committee of the American Institute of Mining and Metallurgical Engineers was held on Tuesday and Wednesday, Sept. 21 and 22, in the Assembly Room of the American Annex Hotel, St. Louis, Mo. Preceding the first session on Tuesday morning, the members and guests were registered and presented with the usual Institute badges. The morning session was opened at 10:30 by Ralph Arnold of Los Angeles, Calif., Chairman of the Petroleum and Gas Committee. In his opening remarks, he suggested that the petroleum section specialize more and more on the technical problems of the oil industry and that an effort be made to enlarge the membership of the Institute among the technical men of the industry. The following program was presented : OIL FIELDS OF RUSSIA, by A. Beeby Thompson and T. G. Madgwick, of London, England. Presented by H. A. Wheeler; discussed by Arthur Knapp and R. VanA. Mills. This most comprehensive paper was one of what is hoped to be a series to be presented by some of our foreign members. It is by far the best description in English of the world-famous Baku and other fields of Russia.

Jan 1, 1920

By Gerald Sherman

Asbestos ore is hard, well intersected by free fissuring but not completely enough to avoid heavy secondary blasting, and is a more valuable ore than usual for caving. These factors have resulted in deviations from standard caving practice in details but not in principles.

Jan 4, 1950

By James J. Dowd

The investigation to evaluate the reserves of coking coal in the United States suitable for the manufacture of metallurgical coke is being made by the Bureau of Mines in three parts: (1) To estimate known (measured plus indicated) recoverable reserves of all coking coal; (2) to study the carbonizing properties of coals and coal blends not now widely used for metallurgical coke making; and (3) to upgrade marginal coals through effective preparation. This is the second7j of a series of reports giving the results of studies by counties under part (1) of the investigation. This report covers Indiana County, Pa., which comprises parts of the Smicksburg, Punxsutawney, Elders Ridge, Indiana, Barnesboro, Latrobe, New Florence, and Johnstown Quadrangles. (See fig. 1.) A base map for each bed in each Quadrangle was made to the scale 1 inch equals 1,200 feet. Maps of mines, locations of drill holes, bed and total coal thicknesses, and the outcrop of the bed were plotted on the maps. With all available data plotted, isopach lines were drawn to limit areas of known unmined reserves in beds 0 to 14 inches thick, 14 to 28 inches thick, 28 to 42 inches thick, and over 42 inches thick. These areas of coal reserves also were divided into "measured" and "indicated" categories. All areas in each thickness range and in each category, mined-out areas, areas excluded from the estimate, and areas outside of the outcrop were measured by planimeter on the base maps. Estimates of total reserves 14 inches and more thick and maps for individual beds were prepared from these data.

Jan 1, 1950

By Doug Smith, Gary Taylor, Paul Ogryzlo

"Uranium mining and processing typically requires large quantities of high-grade reactive quicklime for the neutralization and clean-up of contaminated mine water and mill process waste streams. Currently the Saskatchewan uranium industry’s lime requirements are being supplied from deposits located in Manitoba and Alberta, resulting in transportation costs, which equal or exceed the market value of the product. During the summer of 2001, the northern village of Pinehouse located 220 kilometers south of the Key Lake uranium mill, staked two previously discovered limestone deposits. The relatively shallow deposits, known as Missi Island and Sleeping Giant are located in close proximity to one another, approximately 35 km south of Pinehouse adjacent to highway 914. This paper describes the results of a scoping study carried out by AMEC for the development of the two deposits based on a seasonal limestone mine and a continuous 40,000 to 60,000 tpy wood fired calcining plant designed to supply all of the quicklime needs of the Saskatchewan based uranium industry. Also described are the results of calcining and customer acceptance testwork on samples of lime prepared from recent Pinehouse limestone drill core. The potential benefits of the project include a significant new source of revenue for the community of Pinehouse, lower lime costs for the Saskatchewan uranium industry and employment for northerners in the mining, processing and wood harvesting operations.IntroductionInterest in the Pinehouse/Massinahigan River area for limestone was precipitated by the results of a 1977 industrial minerals drill hole program by the Saskatchewan Department of Mineral Resources. These results led to the acquisition of land in the area by Missi Island Mines Ltd who carried out extensive exploration during the period 1978-1982. They discovered a deposit on the southwest side of the Massinihigan River thought to contain approximately seven million tonnes of limestone with an average grade of 94.5% CaCO3. Missi Island carried out preliminary feasibility studies and prepared an Environmental Overview Statement. However, in spite of positive recommendations, the project was dropped in the mid 1980’s."

Jan 1, 2003

By P K. Banerjee, S Kumar

Indian iron ores with less than 62 per cent Fe are currently unexploited, except for a few sectors which export them to foreign countries. It is anticipated that by 2012 the countryÆs domestic steel production is likely to rise to the tune of 60 million tonnes per annum. To meet this requirement, it is necessary to utilise not only the existing high-grade deposits but it is also necessary to look into exploiting the leftover iron ores of lower grades. Hence, reserves with Fe content 62 per cent and below (particularly the ores with In the present paper, an attempt has been made to beneficiate three different types of low-grade iron ores selected from three different parts (states) of the country. In the paper, alternative routes for beneficiation and effective utilisation have been tested using different techniques in the laboratory in an attempt to match their (Al2O3/SiO2) ratio after thorough characterisation and liberation studies. The paper also encompasses the geological formations, occurrences and distribution of Indian iron ores as well as highlighting the problems associated with the fines, possible metallurgical routes, and their market segregation from the perspective of end users.

Jan 1, 2007

By S M. Aminossadati, R Bagherpour, F Hasheminasab

Mine ventilation is an essential part of underground mining operations used to provide fresh and cool air, as well as to dilute and remove contaminants from the work environment. This paper presents an overview of the ventilation and gas management systems in one of the underground coalmines in Iran: Parvadeh_1 mine. The mine is located in the Tabas coalfield in the South Khorasan province. It is the only fully mechanised mine in Iran utilising the longwall retreat technique. The mine produces 1.1 to 1.3&#160;Mt of coking coal annually. The mine ventilation system currently utilises two 630&#160;kW exhaust surface fans. The gas management system includes surface to in seam (SIS) predrainage boreholes. The underground mine is equipped with an underground gas reticulation pipeline that is connected to a surface plant for the production of methane gas. This study shows that the ventilation and gas management systems of the Parvadeh_1 mine are in line with the standards of Australian underground mines.CITATION:Hasheminasab, F, Aminossadati, S M and Bagherpour, R, 2017. An overview of ventilation and gas management systems in an underground coalmine in Iran, in Proceedings Australian Mine Vent Conference 2017, pp 41–46 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By E. P. Abrahamson II

The effect of transition elements which form binary solid solution upon the recrystallization temperature of zirconium has been investigated. All additions raised the recrystallization temperature. A correlation is obtained between the logarithm of the rate of change of recrystallization temperature with atomic percent solute and the free atom ground state electron configuration of the solute element. ThE work of Abrahamson, et al., on dilute binary solid-solution alloys indicated a correlation between the free-atom ground state electron configuration of the solute and either the brittle-ductile transition or recrystallization temperature. These studies were carried out on bcc base materials. The implication is that the outer s and d electrons of the solute are the prime determinant of the absolute rate of change of recrystallization or transition temperature. Furthermore, the limit of linearity has been shown to be a function of solute electron configuration for recrystallization in iron and vanadium. To date no Complete systematic recrystallization study of dilute binary zirconium base alloys has been made. It is the purpose of this study to note whether the change in solvent structure from bcc to hcp will influence the correlation. It was also desired to learn more of the role of the electron configuration of the solvent on recrystallization temperature. PROCEDURE All alloys were made using 99.87 pct Zr with 0.01 Cr, 0.04 Fe, 0.006 Hf, 0.003 Mg, 0.003 Mn, 0.003 N, and 0.080 0 (132 BHN). The solute elements were 99.9 pct pure. According to the published binary phase diagrams6 and metallographic examinations at X750, all alloys used were solid solutions. The alloys were arc melted and remelted six times in the form of cubic 200-g buttons under an argon atmosphere. They were then hot pressed at 950°C to 0.450 in., upset pressed to 0.350 in., and annealed at 800°C for 1 hr. The specimens were then Blanchard ground to 0.250 in., removing 0.050 in. from each side. The grain size of the material at this stage was found to be 8000 100 grains per sq mm. The specimens were then cold rolled to 0.130 in. and cold pressed to 0.125 in., yielding 50 1 pct cold work. All alloys were then chemically analyzed for the principal addition. The interstitial contents remained at the values of the starting material when checked on random alloy specimens. The rolled sheet was cut into 6.75 by 0.25-in. lengths and heat treated in a gradient furnace for 1 hr. The gradient was 250o to 900°C over the 6-in. length, recorded continuously by six thermocouples resting on each specimen. Control was 3oC, accomplished at the hot end. The recrystallization temperature was determined metallographically using polarized light. The criterion chosen was the point on the specimen showing the first recrystallized grain at a constant magnification, X200. Specimens were repeated, and the agreement was found to be 3°C. RESULTS Three different pure zirconium specimens were tested, and the recrystallization temperature was

Jan 1, 1962