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The Electricity Generating Authority of Thailand (EGAT) Mae Moh coal mine is an open-cut coal mine in Thailand that produces about 16 Mt of lignite annually to generate 2400 MW of electricity. The surface mine pit covers is 4 km by 7 km with mining depths ranging up to 260 m. A large pit slope is formed with the progression of the mining operation. However, massive slides in the pit slope occur often due to the existence weak planes such as faults and bedding, and the weak mechanical properties of the rocks. Hence, 200 m to 300 m boundaries of rock block including coal seams are left in front of faults in order to prevent slides and maintain the stability of the pit slope. As a result, there are significant coal reserves beneath the abandoned area along the pit slope. Moreover, the mined coal seams are very thick and their thickness range from 15 to 30 m.This paper discusses the application of multi-slicing highwall mining system with stowing to this very thick coal seam left around large pit slopes by means of numerical analysis.

Dec 6, 2010

By Christian Wawrzyniak

An analysis method for modeling compensation grouting based on the finite element method is presented. By this method the design parameters of compensation grouting, grouting pressure and grouting volume, can be evaluated. Also the subsidence of a building due to tunnel driving as well as the lifting of the building by compensation grouting can be simulated. The stress changes in the tunnel lining and in the foundation of the building are computed as well. The application of the analysis method is demonstrated on two examples for compensation grouting in combination with construction of tunnels.

By Orlando Ramírez

El presente trabajo describe el sistema integrado de seguridad a través de la norma OSHAS 18001 - 1999 y calidad ISO 9001 – 200m, donde la aplicación de la integración controla las desviaciones de los procesos oportunamente. Es decir, que a través de la procalsedad se reúnen tres elementos: productividad, seguridad y calidad,logrando una ventaja competitiva en el mundo globalizado.

Sep 12, 2005

By Inn-Joon Park

Major problems associated predicting soil-structure interaction behavior are based on the fact that soil is neither homogeneous nor elastic and soil properties are spatially variable. There also exist significant coupling problems between the behavior of the structure and geologic media. When designing foundation or other geotechnical structures, the load transfer between the soil and structure takes place at the contact surface. This surface is called the interface. The behaviors of interface play an important role in the load-deformation response of soil-structure interaction systems. The purpose of this study is to develop improved model for simulation of saturated sand-steel pile interface behavior based on a general concept, called the disturbed state concept (DSC), which can characterize the behavior of saturated soils under dynamic loads. In this study, the Disturbed State Concept (DSC) constitutive model is calibrated and modified for steel pile-saturated sand interface and interaction by using the continuous hardening model for relative intact (Rl) state and the critical state model for the fully adjusted (FA) part in the saturated sand material. The general formulation for implementation has been developed. Then, the DSC model with modification for interface and saturated sand is implemented in finite element program based on the generalized Biot's theory. The interface tests under one-way monotonic and two-way cyclic loading and cyclic triaxial tests are executed for defining the parameters for interface and surrounding soils. Based on these parameters, steel pile-saturated sand interface and interaction are numerically simulated using the finite element program modified in this study. The DSC predictions show improved agreement with the observed results from laboratory test.

Jan 1, 2002

By A. C. Johnson

This circular is one of a series published by the Bureau of Mines describing mining and beneficiation methods and costs at various mining operations throughout the United States. Inclusion of the Abbott mine in this series is of particular interest, as the complex geology and the character of the deposits make their exploitation a unique operation. The mine operates on a high-cost, comparatively small-scale basis, and only the persistence of an aggressive management has enabled it to maintain its rank among the major mercury producers of California. Rising costs and decreasing metal prices, which continuously threaten the low profit margin, are reflected in increased efficiency of operation. This report summarizes past operations and describes, in detail, the geology and ore deposits; exploration and mining methods; and furnacing and condensing operations. It covers the entire operation from initial exploration to the actual production of mercury. Comparative production costs for 1944 and 1958 are of special interest.

Jan 1, 1962

By A. N. Clay

In recent times, there has been criticism of the minerals industry over the lack of quantifiable boundaries between inferred, indicated, and Measured resources. A recent initiative through the United Nations aims to try to converge the mineral resource classification systems. Since the oil and gas industry uses a probabilistic approach to defining reserve boundaries, it is appropriate to introduce a similar statistical methodology for minerals. The Venmyn Variance Tower has been developed based upon traditional statistics to utilize historical and ongoing information in order to quantify variance of geological and chemical parameters and the boundaries and logic for quantitative mineral resource classification. It is proposed that a less than 50% variance from the mean of all sample parameters is required to achieve the classification threshold to define an inferred Resource whereas between 20-10% is needed for an indicated Resource and less than 10% variance from the mean is needed to declare a Measured Resource. These limits are similar to those used by the oil and gas industry, and it is suggested that these thresholds be adopted as an industry standard to ensure consistent quantitative reporting. While this process is intended to use statistics of an orebody to provide quantifiable and defendable boundaries, it cannot be carried out unless the geology of the mineral deposit is understood and the borehole samples can be categorized into appropriate populations for which the statistics are valid. This means that competent geologists are always required to work with and understand the implications of the Variance Tower results. This paper is intended to form the basis of a series of publications that establish a process to take mineral projects along a quantifiable and logical development path. Hence, no specific field example of the practical application of this process is given here.

Jan 1, 2012

A BRIEF DESCRIPTION OF TELPHER HANDLING AND BLAST FURNACE EQUIPMENT.The various sections will be described in the following order:(a) Telpher Handling and Storage Bins.(b) Blast Furnaces.(c) Slag Disposal.(d) Bullion Handling to Drossing Kettles.(e) Copper Drossing.(f) Copper Matte Furnace.(g) Bullion Delivery to Refinery.(h) Fume Handling.(a) TELPHER HANDLING.The telpher installation is an all-steel structure designed to carry out the work of assembly and delivery of charge materials to the blast furnaces.To simplify description, the primary telpher installation will be divided into three (3) sections:-No. 1 Section. 395 ft. long, running north and south, parallel to the water front, and so located that coke, which...

Jan 1, 1937

By B. W. Gandrud, A. C. Richardson

"INTRODUCTION The Bankhead mine of the Cane Creek Coal Mining Co. is in the central part of Walker County, Ala., 4 miles south of Jasper. The Mary Lee bed in this part of the State yields a practically free-burning coal which is marketed as a. steam-raising and domestic fuel. As mined, the coal ordinarily contains ash-forming impurities to an extent that makes it necessary to treat the coal by some washing process before it is marketed. At present the Bank-head coal coarser than 3-1/2 inch is hand-picked and the coal finer than 3-1/2 inch is washed in two single-compartment jigsThis paper contains the result of screen-sizing and float-and-sink tests on a representative sample of the run-of-mine coal and the results of tests made to show the amount of coal liberated from impurities by crushing the coarser sizes. .This report is one of a series on the washability of Alabama coals which is being prepared by the U. S. Bureau of Mines and the University of Alabama, with the cooperation of the coal producers of Alabama.SAMPLING AT THE MINE'The Mary Lee bed at Bankhead consists of two benches separated by a rock parting which varies in thickness from place to place in the mine. The top bench has a very uniform thick-nest; throughout the workings and yields about 65.0 per cent of the output. The bottom bench varies greatly in thickness and in nary places becomes too thin to work at a. profit. The sample for the washability study was taken underground at a place which was typical of the mine as a whole. In taking the sample the working face was squared up and a representative section out from each bench. Care was taken to secure a, quantity of coal from each bench proportional to the quantity contributed to the mine output. The rock parting as gobbed in accordance with the usual mining practice. The total sample taken weighed 3 tons."

May 1, 1933

By R. H. Grau, S. B. Robertson, R. B. Krog, T. P. Mucho

Due to the difficulties of ventilating large opening stone mines, the effective dilution of diesel particulate matter and noxious gases has often been problematic. Since stone mines have large openings that develop low air resistances, and propeller fans are designed for low pressure-high volume applications, main mine propeller fans may be a feasible option for ventilating underground stone mines. This paper describes the results of a case study where researchers from the National Institute for Occupational Safety and Health have demonstrated that significant increases in total mine airflow can be achieved and the ventilation improved in a large-opening stone mine by replacing an axial-vane mine fan with two 12-ft diameter propeller fans and adding a line of stoppings. In this study, the use of the propeller fans more than doubled the air quantity from 300,000 cfm to 750,000 cfm, while operating at 50 horsepower less than the original axial-vane fan.

The usual metallurgical, engineering and administrative activities associated with the handling and smelting of ores, and the subsequent handling and treatment of the products of smelting, present also problems of hygiene that engage the earnest attention of executives in all well-managed concerns.Again, associated with the employment of any considerable number of men, there is always present the problem of accident prevention.INDUSTRIAL HYGIENE.In the earliest records of lead min.ing and smelting there are references to the injurious effects of lead oh the health of the employees, and, with the advancement of medical science, lead poisoning has been the subject of many works by various authorities in many countries.Moreover, in practically every civilised country, there are laws governing the conduct of the lead industry, and in most cases these laws stipulate that employees shall receive compensation for disability caused by lead poisoning.This provision gives the problem an economic aspect. Apart from the legal and the economic aspects, however, there is the humanitarian aspect, which implies that the...

Jan 1, 1937

By Teale E. O

The purpose of the present communication is to put on record the discovery, in October, 1916, in the Howqua district, of a new locality for the occurrence of phosphatic rocks in Victoria, and to give a preliminary description of its characters and geological occurrence. Owing to the great use of superphosphates for agricultural purposes in recent years in Australia, search has been stimulated for the discovery of local and workable supplies of phosphatic rocks. Phosphorus is an element very widely distributed in igneous rocks, usually in the form of the mineral apatite, and also occurs in sedimentary rocks and in soils as a detrital constituent. Under these conditions of occurrence, however, the amount of P 205 present in a rock or soil seldom approaches, and very rarely exceeds, 1 %. Very occasionally it occurs in such a concentrated form as to constitute workable deposits. In such cases they are usually of organic origin. Sometimes they occur as geologically recent deposits of guano or rock...

Jan 1, 1918

By Timo Kankaanpää

Keywords: Solvent extraction, dispersion, phase separation, CFD The liquid-liquid dispersion phases are separated by gravity in a solvent extraction settler. This separation step is made more effective by picket fences. The picket fence geometry and its physical placement have a significant effect on the separation process, because the purpose of a fence is to smoothen and control organic-aqueous dispersion flow in the first part of the settler and achieve a deep and dense dispersion layer in the front end of the settler resulting in a clean phase separation. In this study, physical phenomena in the solvent extraction process and phase separation in a solvent extraction settler with and without picket fences have been examined using a commercial CFX software package. It can be concluded that the used CFD-approach proved to be a complementary tool for optimizing and designing the solvent extraction settler.

Jan 1, 2005

By R. Grandori, L. Pellegrini

The construction of the La Joya hydropower plant (Costa Rica) was awarded by the Spanish power company, Union Fenosa, to the Italian Joint Venture formed by the companies SELI SpA and Ghella SpA. The project, located in a mountainous region of central Costa Rica, includes a 7.9-km-long head race tunnel having an excavation diameter of 6.18 m. A double-shielded TBM was selected to perform the tunnel excavation, which involved mainly volcanic rocks in variable but generally very weak conditions. The tunnel crossed long and continuous sections in completely weathered rock masses with no residual cohesion and with high water inflows. The paper describes and analyzes: The special methods adopted to overcome these sections with the TBM includ-ing face stabilization by chemical grout and foams as well small by-pass tunnels in the crown combined with TBM advance/support The grouting design and the grouting method that was implemented to meet the waterproof design specifications and restore the original groundwater level in the mountain The additional geological investigations performed to improve the knowledge of the rock mass in front of the TBM and the outcomes of these investigations The performance of the TBM in different ground conditions and on average along the entire tunnel Finally, the author’s comment about the possibility of implementing and improving the technologies experimented with in this project in future similar applications.

Jan 1, 2007

By R. V. Ramani

One area of study in the Coal Mine Injury Analysis project was to illustrate and enhance the ability of mine safety management personnel to apply analytical techniques to injury experience data and to justify requests for funds for safety enhancement actions on a cost/benefit and other quantitative basis. Four volumes of this final project report detail (1) the objectives and scope of the mine safety management research, (2) the results of literature review, and case studies, and (3) models developed for mine safety management. The four volumes are titled as Volume III: Mine Safety Management, Volume IV: Analytical Techniques for Mine Safety Management; Volume V: Mine Safety Management Case Studies and Volume IX: Training Cost Model. In this volume, the quantitative procedures that have been developed for the mine-specific analyses of accident/injury experience data are presented and their applications are demonstrated in a summary form through case study examples. The quantitative procedures will aid mine safety management personnel to develop focused accident prevention strategies including training, as well as to justify the investment in such proactive programs through cost-benefit analyses.

Jan 1, 1993

By R. D. Berkenkotter

Titanium and iron assays obtained from cores of three diamond-drill holes from the Cebolla Creek titaniferous iron deposit were evaluated by statistical techniques to obtain information concerning the mineral characteristics of the deposit and to make a preliminary determination of sampling requirements for the deposit. A range of sample volumes representing sizes from one-sixth NX core 2 feet in length through full NX core 10 feet in length were prepared by split-ting the NX core with a diamond saw and combining pulverized splits. Results indicate the existence of at least two statistical populations having different average grades of iron and titanium. Each has an assay frequency distribution that is not normal but is highly peaked (leptokurtic). Frequency distributions of assays from specific altered zones of the drill holes appear to be normally distributed. Increasing the cross-sectional area of the sample unit to change assay volume did not result in significant changes either in assay values or the resulting frequency distributions of assays. However, when assay volume is increased by increasing sample interval, the shape of the assay frequency distribution changes, and a normal distribution of assays is approached. Positive correlation exists between titanium and iron assays. The degree of correlation, although very significant, is too low to use for prediction purposes. Although the amount of data from three widely separated drill holes is not sufficient to establish an average grade for this large deposit, it indicates a range of expected assay values and provides some information for determining requirements of future sampling for evaluation purposes.

Jan 1, 1963

By D. E. Kirby

The electrochemical reduction of AlC13 was investigated as a process for the production of aluminum. An externally heated, single-compartment cell with a rammed refractory lining was used with molten KCl-NaCl-AlC13 electrolyte. Aluminum was deposited qt 700° to 760° C with a current of 100 to 200 amperes on a molten aluminum cathode. Chlorine was evolved at a graphite anode and collected and measured to provide a quantitative evaluation of the AlC13 reduction. Aluminum was removed from the cell by siphoning or ladling. Granular AlC13 was added periodically to replenish that depleted from the electrolyte. Concentrations of 7.5 to 17.5 percent AlC13 in the electrolyte were optimum for operation. Anode current efficiencies of 83 to 85 percent were attained, using anode current densities of 5.9 amperes per square inch and an anode-cathode distance of 4 inches. The chemically bonded, alumina liner was resistant to attack by aluminum and chlorine but susceptible to erosion at the surface of the electrolyte. Titanium diboride proved suitable for the electrical connection to the molten aluminum cathode. Aluminum of a purity equal to or better than 1100 series metal was electrowon continuously from commercial AlC13 for a period of 4-1/2 months.

Jan 1, 1970

By D Lichti

This paper presents recent advancements in the MillMapper software technology, developed and used for thickness gauging of liners of cylindrical grinding mills used for mineral comminution. MillMapper uses calibrated laser scanner data captured inside a mill to determine thickness at several million points on all liner surfaces with millimetre accuracy. The paper is structured as follows. First, a review of the technology and its numerous advantages over existing techniques and the value it adds to operations are presented. These are followed by discussion of recently-implemented innovations, including improved visualisation and inspection tools, automatic ball charge volume measurement and automatic mill liner volume/weight measurement. Results from its application at several sites in Australia are presented throughout.

Jan 1, 2007

By L. Andrews

Keywords: mineralogy, phase-chemical, chemical-looping combustion, XRD, SEM, EDS, QEMSCAN, PGM, slag, matte, ilmenite Mineralogy, traditionally associated with concentrator studies, is being increasingly applied to problems in pyrometallurgy. Such investigations commonly make use of a number of techniques, and the results are combined for a meaningful interpretation, which can lead to a successful solution. Mineralogical applications are described from pyrometallurgical operations. Examples are given of studies and investigations involving mineralogy in chemical-looping combustion, feed monitoring to platinum-smelting furnaces, and losses to slag in base metal and platinum smelting.

Jan 1, 2011

By J. T. McCartney

OPTICAL PROPERTIES of U.S. coals of differing rank have been investigated by the Bureau of Mines, for about 20 years. These investigations have been remade to further the development of an objective basis for petrographic analysis of coal and to add to knowledge of the structure and composition of coal and coal components by determining their optical constants in various regions of the electromagnetic spectrum. Various experimental techniques have been used in these studies, including determination of reflectance from bulk specimens and transmittance of thin and ultrathin sections, interferometry, electron microscopy, and election diffraction. Similar studies leave also been made of graphite, the end product of coal metamorphism. The bureau of Mines conducted the first U.S. investigation of reflectance properties of coal components, laying the foundation for petrographic analysis based on arbitrary reflectance classes and for automated reflectance analysis of coals. Optical constants of coals of differing rank and of graphite have been determined in the ultraviolet-visible-near infrared spectrum. Maxima in the optical constants of graphite were observed in the ultraviolet region and were interpreted to be related to transitions of electrons between the valence and conduction bands. Similar maxima for coals, especially high-rank coals, appeared to be characteristic of the presence of graphitelike layers. A special application of optical theory to absorbing, anisotropic materials like graphite and high-rank coals has been developed. Electron microscopic and electron diffraction studies of coals have revealed various ultrafine structures in coal components and have shown the evolution of an oriented, crystalline graphite structure in high-rank coals.

Jan 1, 1967

By Holly J

The period following World War II has seen many changes in stoping techniques at The Great Boulder Gold Mine. The new methods resulted in improved unit production figures, and have given some relief from the rising worldwide cost spiral in the post war years.Significant production figures are shown graphically in...

Jan 1, 1956