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By Herbert H. Einstein

The thrust of research reported in Part I was to collect in-situ data from exploration programs and the published literature, and to empirically establish distributional patterns for these variables. Since discontinui¬ties in a rock mass govern to a large extent its engineering properties and thus the performance of any slope in the mass, work has been devoted to determining the appropriate distributional forms for attitude spacing and length of discontinuities and to distributional properties of resis¬tance and deformability parameters. The conclusion from these analyses is that trace lengths are logNormally distributed and that joint spacing is Exponentially distributed, regardless of orientation of the sampling line, and regardless of whether each joint set is considered separately or not. Joint orientation (attitude) data representing 22 individual joint sets from eight sites (a total or approximately 20,000 joints), do nor strongly support any of the commonly used distributions as broadly applicable in practice. The autocorrelation )f geometric joint properties is also examined. However, no significant spatial correlation could be found even after extensive data manipulation. The investigation of resistance and deformability parameters starts with a review of mechanisms and models that are used to represent them. Review and statistical evaluation of approxi¬mately 2,000 discontinuity shear tests has shown that good statistical estimates for use in reliability analyses can be obtained for friction angles.

Jan 1, 1979

By M. Kaufman, A. E. Palty

The phase structure and aging characteristics of two nickel-base alloys, Inconel 718 and 702, were investigated. Wrought and cast Inconel 718 showed ArisCb as the major hardening phase, as well as ture was positively identified. Inconel 702 had Ni3Al as the major hardening phase, as well as Cr7C3-of the phase amounts with temperature was determined. 1 HE value of phase structure and aging rate information in the utilization of alloys has been well established. As part of a continuing program, the results obtained on two nickel-base alloys, hconel 718 and Inconel 702, are presented here. Inconel 718 is a relatively new alloy considered for application in both sheet and cast form. Its novelty lies in the use of high columbium tantalum levels in a Ni-Cr-Fe base. No previous work on this type of alloy has been reported in the literature. Inconel 702 is being used now as an oxidation-resistant sheet alloy. Occasional fabrication problems spurred work on its basic structural behavior. The composition of 702 is essentially nichrome plus aluminum and titanium for strengthening and added oxidation resistance. This puts it in the basic class of other nickel-base alloys which have already been studied. The two alloys will be treated separately. INCONEL 718 Phase Study Methods. The phases present after the various conditions investigated were determined by X-ray diffraction analysis of two different elec-trolytically extracted residues and microscopic examination. The extraction methods, using 10 pct HC1 in alcohol and 10 pct H3PO, in water and the X-ray technique have been described previously.' The effect of temperature on the phase behavior was studied on sheet material using the following heat treatments: 2250°F, 2 hr, ice brine quench 1300 100 hr, water quench 2250°F, 2 hr, ice brine quench 1400°, 100 hr, water quench 2250°F, 2 hr, ice brine quench 1500°F, 100 hr, water quench 2250o 2 hr, ice brine quench 1700°F, 48 hr, water quench 2250°F, 2 hr, ice brine quench 1850°, 24 hr, water quench 2250°, 2 hr, ice brine quench 2000°F, 6 hr, water quench The high solution temperature was an attempt to dissolve as many phases as possible without causing melting. Aging exposures were made longer than normal heat treating times in order to approach equilibrium conditions more closely. Cast material was examined only in the as-cast condition and with the normal heat treatment (1700°F, 1 hr, air cool 1325oF, 16 hr,air cool). Materials. The full phase study was performed on sheet specimens approximately 1/2 in. by 2 in. by 1/16 in. The cast pieces were cut from the gating system of a vacuum-cast test piece. An all weld-metal specimen was made by running many weld beads on the sheet using filler made from the sheared edges of the sheet. All external contamination was removed by belt-sanding followed by an electro-polishing treatment. The typical composition of wrought Inco 718 is as follows: The alloy is air-melted. Cast hco 718 may have higher molybdenum. Due to the expectation of finding a Ni-Cb phase (Ni, Cb) for which no X-ray diffraction pattern was available in the ASTM Index, a special 5 Ib heat to the stoichiometric composition of this intermetallic

Jan 1, 1962

By C. M. McCulloch

The natural vertical fracture system in bituminous coalbeds is called cleat. Cleat orientation commonly controls the direction of mining with major development paralleling the face cleat. Previous researchers have categorized the origin of cleat as endogenetic, relating the origin of cleat to compaction and coalification, and exogenetic, relating the origin of cleat to tectonic forces. In the coalbeds studied for this report it was found that tectonic forces were the controlling factor of cleat formation. Face cleats were formed as extension fractures during structural deformation, and butt cleats, as release fractures during erosion and uplift. The face cleat of the Pittsburgh coalbed rotates from N 80° W in north-western West Virginia to N 57° W in southwestern Pennsylvania; the face cleat maintains a perpendicular orientation to the shifting axial trend of local structures. Cleat orientation in other bituminous coalbeds in Virginia, Utah, Oklahoma, and Central Pennsylvania showed a similar relationship to local structure. Directional permeability of coal is directly related to cleat. Holes drilled perpendicular to the face cleat yield from 2.5 to 10 times the amount of gas released as compared with holes drilled perpendicular to the butt cleat.

Jan 1, 1974

By J. D. Davis

On May 15, 1936, Congress authorized the Bureau of Mines to conduct certain studies, experiments, and investigations of subbituminous coal and lignite .4/ Appropriations were made in July 1937, and since that date an active investigation has been underway to complete the provisions of the act. Part of the investigation has included a comprehensive survey of the known properties of the lower-rank non-coking coals, and provisions were made to obtain more data on certain varieties. In line with this plan, a typically subbituminous coal was selected for an extended series o tests in the standard Bureau of Mines-American Gas Association unit,5/ at the Central Experiment Station. This particular noncaking coal was the first one of its rank that ha& been tested in the apparatus; for this reason the results are of particular interest because the testing apparatus was originally designed for use in studying the coke- and gas-making properties of coking coals. The test as described below has been developed by the Bureau of Mines since 1927 through a cooperative agreement with the American Gas Association.6/ Ninety to 180 pounds of coal is heated in a circular retort, 13 to 18 inches in diameter, at wall. temperatures ranging from 540°C. to 1,110°C. in 100°C. steps. All products axe collected and measured; their physical and chemical properties axe then carefully determined to ascertain the gas- and coke-making properties of the coal.

Jan 1, 1939

By Carmen Mihaela Neculita

Sulfate-reducing passive bioreactors efficiently treat acid mine drainage (AMD) by increasing its pH and alkalinity and by removing metals as sulfide precipitates, in addition to hydroxides and carbonates. However, the new mining legislation sets discharge limits based on physicochemical parameters and on the non-toxicity of treated effluent as well. In this study, toxicity was assessed for effluent from 3.5 L column bioreactors filled with mixtures of natural organic carbon sources and operated at two different hydraulic retention times (HRTs) of 7.3 d and 10 d for the treatment of a highly contaminated AMD. Acute toxicity was observed for D. magna, and a toxicity identification evaluation (TIE) procedure was performed to identify potential toxicants. To help the interpretation of the toxicity results, metal partition in the effluent was also determined by filtration and ultrafiltration, while geochemical modeling was performed for metal speciation evaluation. The 10 d HRT effluent was nonacutely lethal for rainbow trout but acutely lethal for D. magna, whereas the 7.3 d HRT effluent was toxic for both organisms. The toxicity to D. magna was eliminated by 2 h of aeration for the 10 d HRT effluent, and the TIE procedure suggested iron as a cause of toxicity. However, the 2 h aeration eliminated the toxicity of the 7.3 d HRT effluent, only if performed after the pH rising to 9.3. Data regarding metal speciation indicated instability of both effluents during aeration and were consistent with the toxicity being caused by iron. The study indicates that design of passive treatment should include sufficient HRT and posttreatment aeration to meet acute toxicity requirements. Keywords: acid mine drainage, sulphate-reducing passive bioreactors, hydraulic retention time, effluent toxicity, metal speciation

Nov 1, 2008

By Henri-Louis Jacob et Marc Bélanger

La province de Québec est un important producteur de roches et de minéraux industriels. En 1998, la valeur de cette production se chiffrait à 1,26 milliard de dollars canadiens (données préliminaires). Les minéraux industriels produits comprenaient: l'amiante extraite des gisements de chrysotile associés aux complexes ophiolitiques de Thetford Mines et d'Asbestos; l'ilménite et les scories enrichies en titane produites à partir du gisement d'ilménite massive du lac Tio associé au complexe anorthositique du lac Allard; le talc produit dans la région de Thetford Mines, à partir des roches à talc-carbonates associées à des feuillets de serpentinite; le mica broyé produit à partir de l'intrusion de suzorite du lac Letondal; le graphite en paillettes extrait du gisement du Lac-des-Îles; la wollastonite extraite d'une zone de skarn dans un lambeau de roches métasédimentaires enclavé dans le massif d'anor-thosite du LacSaint- Jean; le sel extrait aux Îles-de-la-Madeleine d'un gîte associé aux évaporites du Croupe de Windsor. Les nombreuses carrières dans le sud du Québec produisent, en plus de la pierre concassée, diverses substances incluant la pierre dimensionnelle (granite surtout); le calcaire pour la chaux, le ciment ainsi que divers usages industriels; la silice extraite à partir de formations de grès ou de quartzite. Le Québec est aussi un important producteur de tourbe de sphaignes qui est extraite de vastes tourbières qui se sont formées un peu partout dans le sud du Québec à la suite de la dernière glaciation. Les autres ressources en minéraux industriels comprennent des gîtes déjà exploités de brucite, de chromite, de magnésite dolomitique et de feldspaths ainsi que des gîtes de magnésite, de barytine et d'apatite faisant présentement l'objet d'évaluation.

Jan 1, 2001

By Norbert Patzelt, Johann Knecht

Future ore reserves of major gold producers in North America and elsewhere will consist of refractory gold ores. About 60 % of the current U.S. gold production is mined in Nevada. Several of the large gold operations in this state indicate that 40 to 90 % of their future ore feeds will contain refractory gold. To com­pound problems, average head grades for refractory U.S. gold ores had fallen from 8 - 9 g/mt to about 4 g/mt by 1991. In Latin America, 52 % of the gold operations will require milling for optimal recovery. Deeper reserves are, like in North America, refractory. Therefore a special treatment process is needed in order to allow for the gold ore to be leached downstream in a conven­tional cyanidation process for a high gold recovery. There are several options available for this oxidation process like treat­ment of the gold bearing ore in pressure oxidation, in a biooxi­dation or in a roasting plant depending on the reason for the refractoriness. If organic carbonaceous matters and sulfides are the prima­ry reasons for the refractoriness, whole ore roasting is a pre­ferred method for the treatment of this type of ore. Since dry ore is to feed to the roaster, a dry grinding mill is advantageous. For the dry grinding system, the moisture content and the ore char­acteristic is of importance. Those parameters decide the mode of the grinding system. For autoclave systems common wet grind­ing systems can be applied. This paper deals with technical aspects for dry grinding plants and gives an outlook on and pos­sibilities for new grinding systems.

Jan 1, 1996

By Ian McC. Stewart

"Seam gas flow in coal mines takes place through a medium which has both capacity and resistance and can therefore be expressed in terms of the basic diffusion equation, provided that the characteristics of the system can be adequately described. It may be possible to lump the variations from point to point in a seam together as an effective diffusivity. The paper discusses the characteristic flow-time patterns for various types of openings and the particular features of coal and seam which influence the diffusivity.Two field experiments are described in which gas make to a heading and to a borehole were measured in a mine for which considerable data on coal sorption properties were available. Incremental gas flow measured from the borehole experiment predicted the actual flow from the heading measurements remarkably well. The effective permeability adjacent to the face was much higher than expected from the properties of the coal. The incremental flow measurements to a horizontal (in-seam) borehole showed a striking picture of advancing 'relaxation' behind the face which is not discernible by other experimental means."

Jan 1, 1971

By A. Soderberg

This paper describing the mining practice at the Utah Copper Co., Bingham Canyon, Utah, is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The Utah Copper Co. operates the low-grade open-out copper mine at Bingham Canyon, Utah, which is 30 miles in a southwesterly direction from Salt Lake City. In addition to the mine the company operates two flotation concentrators, the Magma plant and the Arthur plant, which have a combined capacity at maximum metallurgical efficiency of 60,000 tons daily. The concentrators are at Magna, about 18 miles from the mine. The company operates its own standard-gage railway, known as the Bingham and Garfield Railway, between the mine and the mills (fig. 1). Concentrates are smelted at the Garfield smelter of the American Smelting and Refining Co., situated 4 miles from the mills.

Jan 1, 1930

By N. O. Johnson

This is one of a series of-Information Circulars dealing with mining and milling methods and costs at mines in various districts in the United States. The Hog Mountain gold mining district is of the northern edge of Tallapoosa County, in the east central part of the State of Alabama. The district is equally close to Goodwater and to Alexander City, both stations on the main line of the Central of Georgia Railroad. From Alexander City the mine is reached by 13 miles of graded road, traveling in a northeast direction. In dry seasons the road is good; in wet weather it is bad but passable. Improvements are being made constantly on the road, so that in the near future the gravel road should be good under all weathered conditions.

Jan 1, 1936

By C. Haycocks

The problems caused by interaction in multi-horizon mining are world wide and are not limited to the coal industry. These problems will continue to increase as mining of new seams multiplies and replaces production from mined out horizons. Interaction problems are particularly evident in the Appalachian coal fields which contain many mineable, contiguously placed coal seams. Selection of the mining sequence of these seams, historically and currently, is based primarily on considerations of seam ownership, availability, and economics. Experience has shown, however, that mining any seam can seriously affect subsequent operations in coal seams both above and below the one being mined. This interaction effect is often detrimental to the recovery cost and safety of mining the subsequent seams. Designing to avoid or minimize interaction effects represents a major challenge to the modern coal mining industry and therefore is the focus of this research. In an effort to evaluate past interaction effects and provide guidelines for future mine design, interactive ground control problems were categorized into four areas. These are pillar load transfer, massive interseam shearing, subsidence and pressure arching effects. To facilitate research, each of these areas was studied separately although in reality these subdivisions are arbitrary and have considerable overlap.

Jan 1, 1983

By Renato Affonso de Lima

As colunas utilizadas para a produção de hidrogênio em fornos de reforma a vapor são submetidas a temperaturas da ordem de 900°C. Dessa forma, os aços inoxidáveis austeníticos da classe HPNb se mostram adequados, devido ao endurecimento por precipitação de carbetos de cromo e de nióbio. Sob determinadas condições de serviço, os carbetos de nióbio podem se transformar em um siliceto conhecido como fase G. A interface desta fase com a matriz austenítica é citada na literatura como local preferencial para a nucleação de danos de fluência. Sendo assim a quantificação das fases presentes é importante para a avaliação do acúmulo de danos em serviço. Diante disso, a simulação termodinâmica computacional se mostra uma importante ferramenta, para a previsão das fases presentes. Técnicas como a analise quantitativa das fases presentes por meio de imagens são consolidadas, porém demandam amostras devidamente preparadas e um alto custo de equipamentos na execução destas análises. Isto posto, o objetivo do trabalho é comparar as simulações termodinâmicas computacionais com o resultado obtido por meio de análise quantitativa de imagens geradas por microscópio eletrônico de varredura.

Oct 30, 2017

By K. L. Paciorek

The aim of the present study was to determine the thermal oxidative behavior of materials used in coal mines, with emphasis on the type and relative concentration of the products, in particular the toxic species formed. To supplement this work and to gain understanding as to the type of products possibly formed and also to assess the limitations and advantages of the various analytical methods used a literature survey of the past investigations performed on the compositions of direct interest to the subject program was conducted. The compositions thus covered were cellulose, polyvinyl chloride, neoprene, urethanes, polyamides, polyesters, polyethylene, epoxy, phenoxy, urea-formaldehyde and melamine formaldehyde resins. The results of this review are compiled in the Appendix. The experimental work consisted of thermal oxidative degradation of 36 materials and 4 composites using a stagnation burner apparatus developed in these laboratories which affords a dynamic system approximating somewhat the conditions encountered in underground coal mines. This technique as employed during this program gave only the relative product concentration at specific periods of the decomposition process, The advantage of this approach is that in this manner screening of materials can be accomplished in conjunction with some assessment of the decomposition rate as influenced by temperature and material composition. Limited static tests were performed using a sealed tube method. The materials studied were grouped according to their compositions. The following were the main groups: (a) polyvinyl chloride-containing materials, (b) neoprene compositions, (c) rigid foams (urethanes, isocyanates), (d) miscellaneous materials (including jute, fiberglass, polyethylene and some articles of unknown composition), (e) coal and fluids (phosphate esters, organic esters, oil-water emulsions), and finally (J) composites. The latter comprised a mixture of a phosphate ester fluid with (a) coal, (b) a representative polyvinyl chloride sample, and (c) a neoprene type composition.

Jan 1, 1972

By I. Haskett

ABSTRACT The Redwater pool, in north-central Alberta, was discovered in October, 1948, and at the end of 1950 was about 85 per cent developed. Production is from a Devonian coral limestone reef and is found at an average depth of 3,150 feet. The pool has an estimated .productive area of 37,000 acres, and a maximum oil zone thickness of slightly over 200 feet. Wide variations exist in both type and values of porosity, with the average value determined for the reservoir being 6.16 per cent. The total stock tank oil in place is about 1.24 billion barrels. The crude has a saturation pressure of 485 psig, com-pared to the original value of 1,050 psig for the reservoir, and the principal recovery mechanism so far has been the natural water drive. Cumulative production to January 1st, 1951, has been about 15.5 million barrels. These withdrawals resulted in a reservoir pressure decline of slightly over 100 psi. Predictions of future behaviour indicate that the water drive will not be of sufficient magnitude to maintain the reservoir above saturation pressure past 1953, and that, with natural depletion, the pool will be produced largely by a solution gas drive. Pressure maintenance by water injection has been considered and the possibility of raising the pressure to the original value of 1,050 psig is also discussed. INTRODUCTION WITH the discovery of the Lewduc pool, early in 1947, the Devonian limestone became the major geological formation contributing to Western Canada's rapidly growing petroleum reserves. Redwater, discovered in October, 1948, is now the largest known Devonian pool in Canada, with a recoverable reserve estimated at approximately 500 million barrels. Until recent years, the knowledge of the nature and characteristics of this type of limestone reservoir has been comparatively limited.

Jan 1, 1951

By C. P. Bowie, George L. Gates

"INTRODUCTION Experience in drilling oil and gas wells has shown that the voidance of blow-outs, twist-offs, fishing jobs, loss of circulation, and heaving and caving of shale formations into the drill hole depends largely on how well the drilling-mud fluid serves its purpose. A possible method for the control of the drilling fluids may be seen from a study of the relation between the particle-size distribution and some of the important drilling-fluid properties, such as the ability to build quickly a relatively impervious mud sheath on the wall of the hole in the porous formations penetrated by the bit during drilling operations. In a wartime economy, which urgently requires conservation of steel, proper functioning of the drilling fluid is particularly important because, as Parks 4/ has stated, intelligent use of good drilling fluids makes possible drilling of wells for thousands of feet in open holes without the necessity of setting protective strings of casing to control the movement of salt water, gas, and troublesome formations into the borehole; consequently, especially in deep wells, of proper drilling fluids materially reduces the need for casing and lowers the cost of drilling and completing the wells."

May 1, 1942

By D. J. McParland

This paper will deal with some of the considerations which, were involved in the design and construction of the uranium mills in the Elliot Lake area . These plants, eleven in number, range from 1500 to 6500 tons per day milling capacity. Most references are with respect to the seven plants in the Rio Tinto Group which have a combined milling capacity in excess of 20,000 tons per day. In dealing with such abroad subject as mill design, one has the choice, of covering a few specific problems in great detail, or else attempting to cover many subjects superficially and briefly. In preparing this presentation, an attempt has been made to compromise on these extremes, and to select some interesting illustrations which are of general interest in the field of mill design, and of value to persons concerned with mill design broadly, beyond the field of uranium mills.

Jan 1, 1959

By M. R. Geer

The widespread adoption during the past decade of the dense-medium process for cleaning coal increases the need for technologic studies of the process. Such studies provide information that will insure maximum usefulness of this process in its present form and may well lead to substantial improvements in design and opera¬tion. The Bureau of Mines has published the results of cleaning trials on a wide variety of coals in two dense-medium pilot plants5/ and reported the recovery of coal from waste by dense-medium treatment.6./ The present report deals with the viscosity of magnetite dense medium, an important subject about which virtually nothing has been published. Specifically, the report concerns methods for measuring viscosity, the influence of various medium contaminants on viscosity, the effect of viscosity on cleaning results, and the influence of viscosity on consumption of medium. Cleaning trials on four coals of varied density composition in a pilot plant, using mediums of different viscosities, showed a steady reduction in cleaning efficiency with increasing viscosity in every instance. However, the behavior of each coal in a viscous medium was distinctly individual. With one, an increase of only 1 centipoise in viscosity caused a reduction in recovery efficiency of 7.7 percent, whereas the same increase in viscosity with another reduced recovery efficiency only 2.7 percent.

Jan 1, 1957

By Dennis A. Hansen

As part of a U.S. Bureau of Mines program to develop a more continuous titanium metal extraction process that uses domestic resources, a study was made to determine the extraction of titanium (Ti) and iron (Fe) from New York rock ilmenite using fluosilicic acid (H2SiF6). The effects of leach temperature, acid concentration, and particle size were investigated for the rate at which Ti and Fe are extracted from the ilmenite. Within the leach time studied, the extraction data fit a shrinking-core model; the rate-controlling step was diffusion of H2SiF6 through an ash layer resulting from a heterogeneous leaching reaction. The rate is linearly dependent on the H2SiF6 concentration and is inversely proportional to the square of the particle diameter. Using 2.6M H2SiF6 at 85°C, 49% of the Ti and 53% of the Fe in 44-to 74-µm New York rock ilmenite were extracted in 3 h.

Jan 1, 2010

The problem of separating the constituents of a mixed gas has assumed increasing importance to chemical technology during the last several decades. Metallurgical practice, dealing mostly with the application of gases as fuel, such as for the oxidation or reduction of ores, has not often confronted an important need for such separations. If theory occasionally has indicated advantages in the use of purified or separated gases, as for example the "dry" blast for the iron furnace or oxygen-enriched blast for a variety of smelting operations, the economics of the proposals has not often been satisfactory. It has seemed evident that the practice of the chemical plant was too expensive with regard to installation or material costs, or both, for the needs of the basic smelting industries and indeed was applicable commercially to metallurgical purposes only when the metals in question were especially valuable or pure. This bulletin deals with a new mechanical means of attacking the problem of separation. Although it is improbable that any one type of separation could hope to find universal application, the method described is to be regarded as an alternative to conventional means that has attractive possibilities in certain instances. It extends the number of methods previously available by one that has not before been applied commercially and that utilizes a well-known property of gases that never has received effective technologic attention.

Jan 1, 1940

By N. Kanari

Chalcopyrite concentrates and their pure constituents were chlorinated by C12+N2 between 25 °C and 750 °C. The reaction products were analyzed by SEM, XRD and chemical analysis. The effect of gas flow rate and chlorine content of the gas mixture on the reaction rate were investigated. At room temperature, these solids start to react with chlorine giving metal and sulfur chlorides. Complete reaction is achieved at about 300 °C and the iron and sulfur chlorides were fully volatilized. The chlorination residue is composed of valuable metals' chlorides. A simplified flow - sheet for the treatment of chalcopyrite concentrates by chlorine was suggested.

Jan 1, 1998