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Recently discovered Carboniferous bentonites are variable in charadeI and thickness, but being altered aeolian, ash-fall tuffs, they are probably extensive. Most are the Ca-montmorillonite type without the natural swelling characteristics of the Wyoming deposits, but their situation, thickness, and response to beneficiation through cation exchange may give them some potential as sources of future economic deposits.INTRODUCTIONLoughnan and See (1959) gave an account of bentonites and fuller's earth deposits of New South Wales. The most likely potential industrial sources were those occurring in the uppermost formations of the Newcastle and Singleton Coal Measures (Permian) in the Hunter Valley and deposited during epochs not marked by strong contemporary vulcanicity.One feature of the record of known occurrences at that time was the absence of bentonites from the thick volcanic sequences of the Carboniferous, but since this paper appeared, many bentonite beds have been discovered by the writer in the Carboniferous facies formerly known as the "Kuttung Series".The purpose of this contribution is to report briefly on the occurrence, genesis, mineralogy, and economic potential of these deposits which augment possible sources of bentonite near major industrial centres on the eastern seaboard.The potential world demand for bentonite would increase markedly with the trend to pelletization in the steel industry, if its use in this field became more general. More detailed mineralogical studies will be presented in later publications.STRATIGRAPHIC DISTRIBUTIONBentonite occurs at irregular intervals throughout a thick sequence of dominantly continental, plant bearing strata...

Jan 1, 1965

By John F. Oyler

The performance of high alumina refractory subjected to high compressive loads and high temperatures is an area in which operating experience is quite limited. This paper documents the results of five months of operation of a combustion chamber lined with 83 pct alumina brick subjected to compressive stresses as high as 45psi and hot face temperatures of about 2750°F. It also describes a method for predicting long term subsidence results based on the limited information available in standard hot load limit tests. Descriptions of the chamber itself and the pilot plant upon which its design was based are included.

Jan 1, 1978

By Theron A. Klinefelter, Sidney Speil, Sidney Gottlied

"INTRODUCTION The investigation of domestic talcs by the United States Department of the Interior Bureau of Mines, was initiated in December 1941 at the request Gen. Charles Hines of the United States Army. The urgency for such study was expressed by General Hines as follows:The radio-manufacturing industry has recently been expanded by the Army to provide sufficient, capacity for defense needs, and considerable concern has been expressed by the supply Arms and Services over maintaining continued availability of supplies of the necessary raw material. These ceramic products are used by the Signal Cores in all Army radio equipment, and to a greater degree in the new special ultra-high-frequency equipment. The Air Corps has recently become a user large amounts of radio-grade ceramics for aircraft spark-plug covers required for high-altitude operations. In addition, the use of this material is essential to the proper functioning of the radio-navigation aids of the Civil Aeronautics Board.Progress in the Bureau of Mines studies on talc was made available to representatives of the Army and Navy through frequent interim reports. Through the efforts of the several war agencies concerned with raw-materials supply and the domestic talc producers, the condition of scarcity that developed in 1942 passed to one of ease in 1943, and has so continued to date. Tentative estimate of reserves delineated indicates a supply of high-grade steatite sufficient to meet military war requirements for at least 4 or 5 years."

Apr 1, 1945

By L. A. Cornish, S. N. Prins, R. Süss

The work is being done using the Thermo-CalcTM software, and the database is being built up by obtaining good thermodynamic descriptions of all of the possible phases in the system. The database supplied did not cover all of the phases, and these had to be gleaned from literature, or modelled using experimental data. Similarly, not all of the experimental data were known, and where there were gaps or inconsistencies, experiments had to be undertaken. A preliminary version of the database was constructed from assessed thermodynamic data-sets for the binary systems only. The binary descriptions were combined allowing extrapolation into the ternary systems, and experimental phase equilibrium data were compared with calculated results. Very good agreement was obtained for the Pt-Al-Ru and Pt-Cr-Ru systems, which was encouraging and confirmed that the higher-order systems could be calculated from the binary systems with confidence. Since some of the phase models in databases were different, these phases had to be remodelled. However, more work is ongoing for information concerning the ternary phases present in the Al-Cr-Ru, Pt-Al-Ru (two ternary compounds in each) and Pt-Al-Cr (possibly more than three ternary compounds) systems. At later stage of the work, problems with the thermodynamic descriptions of the Cr-Ru and Pt-Cr binary systems were found. A programme of experimental work to overcome these has been devised, and is being undertaken. Keywords: Pt-based alloys, phase diagram calculations.

Jan 1, 2006

By D. E. Wolfson

As a part of its overall program of coal carbonization, the Bureau of Mines is studying the coking properties of coals that may be used for metallurgical purposes. The objectives of this study were given in detail in a previous report The inherent suitability of coal for metallurgical purposes depends primarily on (1) chemical composition, (2) preparation characteristics, and (3) carbonization behavior. The first two factors, Be well as the amount of available reserves, are considered in selecting coals for carbonization tests. The selection of coal beds in Harlan County, Ky., for coking tests was based, in part, on recent studies of coal reserves by Wallace,3/ who estimated the recoverable reserves in beds 28 inches or more thick, in tons, as follows:

Jan 1, 1956

By Jack Magtoto, Lysa Voight, Tom Martin, John Forero

SUMMARY Commitment by all parties to partnering goals established early in the contract aided Affholder, Inc. in constructing 2,360m (7,700') of soft ground tunnel in Rancho Cordova, CA. Despite two zones of known contamination, encountering a zone of loose cobbles and boulders in a matrix of flowing sand, some perched water tables and a flooded tunnel after 2 upstream safety plugs failed, the Contractor finished the work 33 days early and only 1.91% over his original bid.

Jan 1, 2007

By Peter Jackson

The dewatering of the large construction pits required for major infrastructure projects often has a significant impact on the environment. This is particularly so in urban areas and where groundwater resources are of interest. These environmental impacts are inter alia, groundwater lowering and the consequent effects such as settlement and deterioration of timber foundations, together with the impact of the dewatering on the groundwater quality. In order to minimise the environmental impact of the dewatering, the quantity of water to be abstracted and the amount of groundwater lowering in the surrounding area must be minimised. This paper describes the measures that have been taken on the Copenhagen metro project to achieve the objective of minimal environmental impact whilst still carrying out a major dewatering scheme.

Jan 1, 2000

By J. Gurland

A method of measuring the degree of contact between grains of 1 phase in multiphase alloys is derived. It is shown that the number and the areas of contacts between grains can be determined by metallographic analysis. Relations between the area of contact, the dihedral angle, and the mean free path of spherical grains are developed. It is often desirable to interpret the mechanical behavior of alloys in terms of structural features observed under the microscope. A quantitative description of microstructures of multi-phase alloys requires consideration of geometrical and topological factors such as the amount, size, and shape of grains and the continuity of the constituent phases. The number and dimensions of grains may be metallographically determined by applying the methods described by Smith and Guttman1 and by Fullman2 in their papers on the measurement of particle size and internal boundaries in opaque bodies. The present work intends to show that the same methods can be used to evaluate some of the parameters of phase continuity; namely, contiguity, number of contacts, and areas of contact of grains of 1 phase. Application of these concepts may be found in such problems as the calculation of electrical conductivity of 2-phase alloys, or the evaluation of the length of fracture path through grains of a brittle phase more or less dispersed in a matrix. I. DEFINITION The following definitions and derivations are based on 2-phase alloys, of which the units of the microstructure are grains. Contiguity is defined as the average fraction of surface area shared by 1 grain of a phase with all neighboring grains of the same phase. In a 2-phase alloy of constituents A and B, the contiguity of phase B is given by: where Cb is the contiguity of phase B aBß is the average area of contact between a grain of phase B and adjacent grains of phase B, aAB is the average area of contact between a grain of phase B and adjacent grains of phase A. The contiguity is a measure of the average degree of contact between grains of phase B in the 2-phase mixture. The ratio varies from 0 to 1 as the distribution of phase B changes from a completely dispersed to a fully agglomerated structure. Smith and Guttman1 have shown that the relative areas of 2 kinds of interfaces in a volume are directly proportional to the number of interfaces of each type intersected by a random line. The lines can be drawn on metallographically prepared surfaces as long as these are random sections through the sample. The contiguity ratio of phase B then becomes: Cb = 2NBB/NAB + 2N BB [2] where: NBB is the number of interfaces between grains of phase B intersected per unit length of random line. Nab is the number of interfaces between grains of phase B and grains of phase A intersected per unit length of random line. The factor 2 arises in Eq. [2] because each interface B-B is associated with 2 grains of B-phase, whereas the interface A-B involves only 1 grain of B-phase. The calculations of contiguity do not require any assumption as to volume fraction, particle size, or particle shape. Fullman2 gives an expression for the determination of the mean free path between particles. The mean free path PB between grains of phase A, i.e., through grains or agglomerates of phase B, may be found from the relationship: PB =2fB/NAB [3] where fB is the volume fraction of phase B. The calculation of the mean free path is independent of grain shape and grain size distribution. The calculation of the number of contacts and of contact area requires assumptions of grain shape, grain size, and contact shape. In the case of uni-

Jan 1, 1959

By K. M. Kim

A site-specific blasting model has been developed for the Asarco Mission mine. The main inputs to the model are the in-situ block size (F80), the post-blast fragmentation (P80) and the intact tensile strength (To). The output from the model is the specific blast energy (ESE). Modern techniques are being used to obtain the input parameters for the site-specific blast fragmentation model. In particular, image processing software is used to obtain both the in-situ block size and the post-blast fragmentation, and the Schmidt hammer is used to obtain the tensile strength at numerous locations throughout the rock mass. An initial model was developed using five test shots in one area of the mine that contains Argillite and is relatively homogeneous. This also included calibrating Schmidt hammer readings against actual Brazilian tensile measurements. The model for Argillite will be updated as more tests are conducted, and the model will be extended to the other four primary rock types at the Asarco Mission mine.

Jan 1, 2011

By G. J. Simandl

"Since the 1980s, China has become the predominant producer of REEs. Recently, it introduced REE export quotas and this started a world-scale REE exploration rush. REE resources are concentrated in carbonatite-related deposits, peralkaline igneous rocks, pegmatites, REE ± P veins, ion adsorption clays, placers, and some deep ocean sediments. REEs could also be derived as a by-product of phosphate fertilizer, U processing, Ti-Zr-bearing placers, and exploitation of Olympic Dam-type sub-type of IOCG deposits. The ideal REE development target would be located in a politically stable jurisdiction such as Canada. REE grade and tonnage, mineralogy, and permissive metallurgy are some of the key technical factors that could be used to screen projects. INTRODUCTIONAccording to the International Union of Pure and Applied Chemistry (IUPAC), the term “rare earth elements” (REEs) encompasses yttrium (Y), scandium (Sc), and the lanthanide series: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). This definition is used throughout this paper.REEs are subdivided into light (LREE) and heavy (HREE) categories. LREEs include, Sc, La, Ce, Pr, Nd, Sm, Eu, and Gd and HREE include Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y. Promethium (Pm) does not occur in nature. Concentrations of individual LREEs in the upper crust of the Earth are comparable to those of base metals. Even the least abundant REE (Lu) is about 200 times more abundant than gold.The production of REEs, reported in the form of oxides (REOs), for 2011 is estimated at 140 000 t (Figure 1a). Although high technology industries can substitute several REEs with other materials, these substitutes are typically more expensive or less effective than the REEs they replace. A number of countries, including the United States, consider several REEs essential for national security, their economy, and a general reduction in green house gas emissions. The forecasted demand for individual LREOs is much higher than that of HREOs (Figure 2). Dy, Eu, Tb, Nd, and Y are essential for the US economy and subject to predicted supply disruptions (U.S. Department of Energy, 2010)."

Jan 1, 2012

By Peter White

Mine Planning Shaft Collar Shaft Sinking Raises Ramp Underground Water Storage

May 1, 2009

By R. Cotton

"1. INTRODUCTIONTo say that the environment will be a dominant issue in the 1990' s is an understatement. A world-wide ""green revolution"" is taking place not only with the general public and politicians, but in the boardrooms and plant facilities of corporations around the world. There is probably not a plant manager who has not been requested by his corporation to assist in some way on environmental issues by providing advice and strategy, by dealing with customer or community concerns, by considering environmental matters in transactions, by developing new environmental compliance policies and requirements, and so on.There are, in the author's view, three main challenges for the mining industry in the environmental area in the 1990's. This paper will discuss each in turn. The first challenge is the concept of ""sustainable development"". Whatever the meaning of this much-debated phrase, we are rapidly moving beyond the buzzword, and into the specifics. It will clearly impact on the way we manage our companies, our communities and our personal lives.The second is the challenge of personal liability; particularly for officers, directors, supervisors and managers of the corporation. For example, in Ontario today, a good percentage of prosecutions for pollution offences are against individuals, usually managers and supervisors, in addition to the prosecutions against the corporation itself for the same offence. In all likelihood, prosecutions will increase in number and will increasingly be directed at individuals. A corporate president has already served a jail term for contempt of court related to his corporation's breach of a court order related to sewer by-law offences. Although the case is on appeal, another president has become the first officer in Canada to be sentenced to jail for violation of an environmental protection statute. Other corporate officers and directors have recently been charged with breach of their duty under Ontario's Environmental Protection Act."

Jan 1, 1991

By V. Labiouse, M. Jaboyedoff

GIS documents are of great interest for a quick and low-cost determination of areas endangered by rockfalls. They allow (i) the detection of potential instabilities from steep slopes and cliff areas, and (ii) the preliminary estimation of potential run-out areas by means of a so-called cone method. After the presentation of the tools used to compute these areas, the paper focuses on two methods developed for a preliminary hazard mapping, one at regional scale and the other at local scale. Mittels GIS-Dokumenten können von Steinschlag bedrohte Gebiete schnell und kostengünstig ermittelt werden. Die sogenannte Kegelmethode erlaubt die Erkennung potentiell instabiler Zonen von Steilhängen und Felswänden sowie eine erste Einschätzung der möglichen Reichweiten. Nach der Vorstellung der zur Berechnung der bedrohten Gebiete benötigten Hilfsmittel stellt der Artikel zwei Methoden zur vorläufigen Gefahrenkartierung in lokalem und regionalem Maßstab vor. Les SIG sont très intéressants pour une détermination rapide et peu onéreuse des zones affectées par des chutes de blocs. Ils permettent une détection des zones potentiellement instables et une estimation sommaire des zones de propagation des blocs par une méthode dite des cônes. Après la description des outils utilisés pour définir ces zones, l’article expose deux méthodologies élaborées pour un zonage préliminaire du danger, l’une à l’échelle régionale et l’autre à l’échelle locale.

Jan 1, 2003

THE following short paper on the Blair Athol coal-field will no doubt have a twofold interest to members from the fact that its main seam, known as the "Big Seam" of a maximum thickness of 91 ft without a band, is unique, being probably the thickestseam of high-grade clean coal yet known, and also because of the interesting problem it presents the colliery engineer-viz., which system of mining is the best to secure the highest economical extraction.Location - Blair Athol is a mining township in Central Queensland, situated at an altitude of about 1100 ft. above sea-level at the end of a branch railway line 74, miles from Emerald, on the Main Central Western line, and 240 miles by rail from Rockhampton.Geology - The coal-measures appear to lie in a shallow basin of about four or five square miles in area, surrounded on all sides by slates and schists, which are overlaid oh three sides by alluvial deposits of up to 150 ft. in thickness, and on the fourth by a thick basalt bed, as yet unproved, some miles beyond which the auriferous slates outcrop. These alluvial deposits have been largely worked in years past and gave high gold returns, the chief diggings being Clermont and Macdonald's Flats in the south, the Springs and Black Ridge in the north-east, and Yankee Creek and others on the west. The surface of the coal-fields may be described as unbroken, but undulating, with gentle southerly dip, the watercourses opening out into wide flats. The absence of creeks or deep gullies accounts for no outcrops being visible on the surface, and the coal-measures...

Jan 1, 1918

By G. S. Camm

Gwynfynydd is a small, high-grade black shale-hosted vein-gold deposit. The Chidlaw Link Zone is the only area being mined and contains 24 000 t ore grading 15.2 g/t gold. Within the Link Zone a complex vein structure occurs consisting of a mother vein up to 5 m thick and narrow (less than 0.5 m) leader veins. The former shows minor variations in dip, strike and thickness, whereas the latter show marked changes in all three. The leader veins are hosted within the footwall zone of the mother vein and both are composed of quartz with galena, sphalerite, chalcopyrite, pyrite and minor arsenopyrite. The vein system is transected by a series of cross-vein and intra-vein dip-slip faults. Pockets of gold occur at vein intersections or branches and within the complex footwall zone and are often related to variations in vein attitude and/or geometry. The Chidlaw Link Zone displays a complex, erratic distribution of gold mineralisation and a multi-stage history of structural activity, fluid flow and mineral deposition

Jun 18, 1905

By Tripathy A. K, Satapathy B. K, Nayak B, Mohanty J. N, Dey D. N

The paper deals with the metallographic tudy of heat treated chromite and chromite-coke composite briquettes. The briquettes, prepared from chromite concentrate of Orissa Mines using molasses-lime, dextrinelime and tamarind seed as binders, were subjected to different temperatures and examined metallographically. The change of phase with temperature was analysed by X-ray diffraction.

Jan 1, 1987

By W. R. Reed, G. J. Joy, B. Kendall, A. Bailey

"Testing of the roof bolter canopy air curtain (CAC) designed by the U.S. National Institute for Occupational Safety and Health (NIOSH) has gone through many iterations, demonstrating successful dust control performance under controlled laboratory conditions. J.H. Fletcher & Co., an original equipment manufacturer of mining equipment, further developed the concept by incorporating it into the design of its roof bolting machines. In the present work, laboratory testing was conducted, showing dust control efficiencies ranging from 17.2 to 24.5 percent. Subsequent computational fluid dynamics (CFD) analysis revealed limitations in the design, and a potential improvement was analyzed and recommended. As a result, a new CAC design is being developed, incorporating the results of the testing and CFD analysis.IntroductionExposure to respirable coal mine dust can cause coal workers’ pneumo-coniosis (CWP), also known as black lung. If silica is present in the dust, the miner may develop silicosis in addition to CWP. CWP and silicosis are occupational respiratory diseases that are ultimately fatal and have no cure. The only method of prevention is to eliminate exposure to respirable coal mine dust and crystalline silica, or quartz. The occupational exposure limit on a Mining Research Establishment (MRE) basis for respirable coal mine dust had been 2 mg/m3 during each shift that a miner is exposed in the active workings of the mine or in mine facilities. Under recently enacted legislation, this standard was changed in August 2016 to 1.5 mg/m3 for a full working shift (The Office of the Federal Register, 30 CFR 70.100, 2015). When respirable quartz is present, the mine must maintain its average concentration at or below 0.1 mg/m3. If the mine exceeds the 0.1 mg/m3 respirable quartz dust concentration, then the applicable respirable dust standard is reduced, calculated as 10 divided by the percentage of quartz present (The Office of the Federal Register, 30 CFR 70.101, 2015).The sources of exposure to respirable coal mine dust for roof bolting occupations include infrequent maintenance and cleaning of the vacuum dust collection system and operating the bolter downwind — in the return air — of the continuous miner (Good-man and Organiscak, 2003). Recent studies have demonstrated that vacu-um dust collection systems are effective in capturing bolter-generated dust if maintained and operated correctly and if proper face ventilation techniques are used. However, most expo-sure to respirable coal mine dust for a roof bolter occurs when the roof bolter machine is operated downwind of the continuous miner (Potts, Reed and Colinet, 2011; Colinet, Reed and Potts, 2013). Because of this higher exposure downwind of the continuous miner, the roof bolter is often limited to working downwind of the miner only once during a production shift."

Jan 1, 2017

By Doris M. Hyde

The economy of Belize continued to show a very slight but still positive growth during 1986. The gross domestic product (GDP) was estimated to have been about $164 million,2 almost the same as those of 1984 and 1985. Foreign investors looked favorably on Belize because it had remained isolated from the sometimes turbulent political and social strife elsewhere in Central America. Reportedly, in late 1986, Guatemala had decided not to pursue its claim to Belizean territory and to give full recognition to that country. Discussions were to be held regarding any matters of mutual concern. New investment possibilities were oriented toward agriculture or manufacturing endeavors. Except for some interest in petroleum exploration, the minerals sector remained limited to the quarrying of construction-related materials.

Jan 1, 1988

By Mei Long, Tawum Juvert Mbah, Jianhua Zhang, Haiwang Ye

There have been many improvements and advancements in the application of neural networks in the mining industry. In this study, two advanced deep learning neural networks called recurrent neural network (RNN) and autoregressive integrated moving average (ARIMA) were implemented in the simulation and prediction of limestone price variation. The RNN uses long shortterm memory layers (LSTM), dropout regularization, activation functions, mean square error (MSE), and the Adam optimizer to simulate the predictions. The LSTM stores previous data over time and uses it in simulating future prices based on defined parameters and algorithms. The ARIMA model is a statistical method that captures different time series based on the level, trend, and seasonality of the data. The auto ARIMA function searches for the best parameters that fit the model. Different layers and parameters are added to the model to simulate the price prediction. The performance of both network models is remarkable in terms of trend variability and factors affecting limestone price. The ARIMA model has an accuracy of 95.7% while RNN has an accuracy of 91.8%. This shows that the ARIMA model outperforms the RNN model. In addition, the time required to train the ARIMA is than that of the RNN. Predicting limestone prices may help both investors and industries in making economical and technical decisions, for example, when to invest, buy, sell, increase, and decrease production.

Jan 6, 2021

By Mayfield P. L J, Honeyands T. A

BHP's two million tonne per annum nominal capacity Hot Briquetted Iron (HBI) plant at Port Hedland in the Pilbara region of Western Australia is based on FINMET¦¦ direct reduction technology. The FINMET¦¦ process produces direct reduced iron (DRI) by reacting fine iron ore with reformed natural gas in a series of fluid bed reactors and then hot briquetting this DRI into dense, high quality iron briquettes. The Port Hedland HBI project represents a major investment in the chemical processing of Australian minerals to higher value products prior to export to Asian markets. This paper describes the FINMET" process and technical aspects of the high-quality HBI product, and provides an update of the current status of the project.

Jan 1, 1999