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By R. L. Mazza

This final report on methods of reducing and controlling methane in coal mine gob areas indicates that vertical degas holes are beneficial to the mines of northern West Virginia working the Pittsburgh Coal. The USBM funded project involved the drilling and testing of eight vertical holes (four over longwall panels and four over room and pillar panels) based on a review of 13 previously in existence. Areas of observation included gas production history, flow entry profile, underground methane reductions, strata separations, and casing loads (accompanying subsidence). Observations led to the drilling of successful holes drilled short of the mine. Eleven gas production response to applied vacuum tests were conducted at nine degas holes under the contract. Significant production responses were recorded over longwall gobs.

Jan 1, 1977

By S Adamson

Morphological analysis of alluvial gold recovered from the same segment of a placer by four common commercial methods indicates that gold shape and the presence of quartz intergrowths or sulphide overgrowths substantially influence the recovery efficiency of each method. The amount and types of gold saved by each method varies according to the different hydrodynamic conditions under which each of the methods operates. Reverse circulation drilling has the lowest efficiency and preferentially loses moderate-high flatness gold and intergrown or overgrown gold particles with relatively low density. Gravity riffle, hydraulic riffle, and jigcentrifugal concentrator systems respectively save progressively more of these problematic gold morphotypes, but still lose significant and sometimes substantial amounts (of profit) to the tailings. Because of the differences in recovery efficiency, reverse circulation drilling probably underestimates the grade of most placers and may have resulted in bypassing several economic deposits. Losses to tailings by commercial recovery plants arise from inadequacies in fundamental plant design features. These inadequacies compromise plant efficiency by limiting the ability of plants to simulate the wide range of hydrodynamic conditions necessary to operate effectively throughout placer systems. Incorporation of sand pumps and multiple recovery methods into the more sophisticated plants only partly overcomes these inadequacies. At best, efficiency will be maximised in a few segments of the placer determined by individual plant design, and will decrease progressively upstream and downstream of those segments. Without prior knowledge of the morphological characteristics of the gold to be mined, it is difficult to choose the most appropriate plant design, or to estimate what proportion of the gold will be recoverable by any given plant. If the relevant relationships are not considered beforehand, the recovery plant is likely to lose a significant proportion of the gold, and sacrifice maximum profit.

Jan 1, 2001

By Roxanne Scott

Outline ? Overview of Community Investment in the Mining Sector ? Emerging Good Practice: ?Strategic Integrated Community Investment? ? Assessing Local Context: ? Institutional Assessment ? Partnership Assessment Approaches to Community Investment Isolation: No proactive engagement in community development Ad hoc philanthropy: small infrastructure, sponsorships, donations Strategic philanthropy: Community proposes options for development Company decides what to do and carries it out, e.g. building schools, health posts, roads Strategic integrated community investment: ? Aligned with government/community development goals and priorities ? Communities and government involved in decisions and execution ? Focused on training and capacity building ? Partnerships ? Continuation in absence of company support Measured returns on investment

May 1, 2010

By Camier R. J, Perry G. J

Extensive deposits of brown coal exist in the Gippsland Basin, primarily in the Latrobe Valley. The total quantities of economically winnable coal in this region of Victoria and in other smaller fields are large enough to adequately assure Victoria's future electricity needs and to also provide large quantities for alternative applications, including liquefaction. As a result of the recent conflict in the Middle East attention has again been focussed on the production of synthetic fuels from coal. There have been many investigations over the years into the production of oil from Victorian brown coal. The purpose of this paper is to summarise the scope, objectives and major findings of these studies, with the emphasis on the direct hydrogenation route for converting brown coal to oil. The principal alternative processes are carboniastion and hydrotreatment of the product tar, or gasification and Fischer Tropsch synthesis of liquids from the product gas. The attractions of Victorian brown coal which have encouraged these studies include: ò the vast reserves of Victorian brown coal and the favourable conditions for low cost mining, ò the high quality of the coal (low ash, sulphur and nitrogen contents), ò the high reactivity of the coal giving high yields of product in hydrogenation to liquid fuels, ò the extensive data base available on the resource and its characteristics, and ò the availability of a skilled workforce and extensive infrastructure in the Latrobe Region to support a major resource development project. These advantages have been partially offset by: ò the high moisture content of the brown coal and the cost of drying, and ò the priority previously given to electricity generation in the allocation of the brown coal resource.

Jan 1, 1992

By P Holtham, K Duffy, W Valery, A Jankovic

As high grade ore deposits are depleted, remaining deposits are generally lower grade and require the mining and processing of larger volumes of material per tonne of product. These low grade deposits often contain a large proportion of barren gangue. Pre-concentration aims to remove this barren material at as coarse a particle size and as early in the process as possible. This has the potential to reduce processing costs, energy and water consumption, increase production and improve resource utilisation.There are several technologies that may be applicable for pre-concentration. This paper looks specifically at bulk ore sorting and how it can be integrated into existing or new mining operations to improve profitability and reduce environmental impact. Bulk ore sorting is the separation of barren gangue from a fully loaded conveyor belt based on the grade as measured or inferred from a sensor measurement. It may be used to increase the production rate through fixed plant capacity, or increase production and/or reduce the size of downstream processing equipment in Greenfield operations. Marginal ore sub-economic reserves may be upgraded, making them economic to treat and improving the resource utilization. Bulk ore sorting could also be used to reduce dilution and ore loss in mining operations by improving grade control, or to separate ore types to treat via different process routes. Various applications of bulk ore sorting are discussed in this paper, and three cases are investigated considering the impact on the overall operation and the associated benefits.CITATION:Duffy, K, Valery, W, Jankovic, A and Holtham, P, 2015. Integrating bulk ore sorting into a mining operation to maximise profitability, in Proceedings MetPlant 2015, pp 273–287 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By B. E. Warren

Jan 1, 1965

By N. S. Yet

This paper shall present the design and construction of bored pile and diaphragm wall for the proposed MHA complex in Singapore. The work was carried out by L&M Foundation Specialist Pte Ltd and PWD Consultants Pte Ltd was the consultant for this project. A brief description of the project is first presented to illustrate the scope and scale of the work involved, which includes the construction of bored piles and diaphragm walls and installation of steel stanchions in the bored piles. This is followed by a description of the methodology used to analyse and design the wall and bored piles. As both towers in this project are supported on bored piled foundation and are constructed by top down construction method, the analysis of the wall has taken into consideration the sequence of work phase by phase and this was carried out by means of a commercial finite element program called CRISP. Modelling of the problem will be briefly described and the findings from the numerical analysis will be presented. This is followed by a description of the structural and geotechnical design aspects of bored piles. The paper shall then describe the difficulties encountered for this project and solution used to solve the problem. The subsoil condition will be described with special mention on the encounter of very strong granitic rock at depth above the maximum excavation level of the basement at certain locations, hence necessitating the drilling of rock for a considerable depth for both bored piles and diaphragm wall. At this juncture, the construction method used to drill through the rock will be briefly described. For construction of bored piles, penetration of rock was carried out by chiselling or drilling using reverse circulation rigs. For construction of diaphragm wall, it requires the employment of Bauer hard rock cutter which uses cutting wheels fitted with roller bits and are capable of excavating into granitic rock of compressive strengths more than 100 MPa.

Jan 1, 2000

By Patrick Polk

For many years, sulfuric acid producers all over the world have been forced to meet ever more strict environmental regulations to reduce SO2 emissions. The sulfuric acid industry has implemented new solutions in order to comply with the new lower SO2 emissions target. Haldor Topsoe (Topsoe) has responded to this challenge by continuously improving the range of VK sulfuric acid catalysts and providing tailor-made catalyst solutions to meet the demands of the sulfuric acid producers for lower SO2 emissions. Reducing emissions through catalysis: requires less capital than installing a scrubber, requires no additional process chemicals, generates no waste or by-product to dispose of. In 1996 Topsoe introduced VK69, a cesium-promoted vanadium catalyst, designed for operation in the pass(es) after the intermediate absorption tower in double absorption plants. The high activity of VK69 allows for a more than 50% reduction in SO2 emissions from existing double-absorption plants. Topsoe currently has more than 110 installations of VK69. To comply with the still more stringent regulations being placed on the sulfuric acid industry to lower SO2 emissions, Topsoe has developed a new sulfuric acid catalyst designated VK-701 LEAP5™. This catalyst was introduced to the market in 2010. VK-701 LEAP5™ is based on a novel technology which circumvents the internal transport deficiencies of existing commercial sulfuric acid catalysts and thereby offers exceptionally high activity in strong, SO3 rich gases. Sulfuric acid plants have used this catalyst to meet emissions requirements lower than previously believed possible with a catalyst only solution. This paper will present examples on how to reduce emissions by implementing a tailor-made catalyst solution using VK69 and VK-701 LEAP5™.

Jan 1, 2014

By Jacques B. Wertz

Although fracture intersections and "domes" seem at a number of places to be the basic structural combination for the occurrence of a mining district, of the porphyry-copper type particularly, this situation is, of course, not always to be expected. For instance, the group of mines comprising Superior, Ray, Miami, Globe, Christmas appeared from the beginning of these structural studies as typical exceptions, and there are others. One had to expect additional parameters to allow for any mineral concentration to occur. One of these apparent parameters is here considered. From the result of stratigraphic studies related to ancient formations in Southeast Arizona, the Martin limestone (Devonian in age) was retained as having a possible relationship with the structure-economic studies in progress, as evidenced for instance by the mineralized O'Carroll bed located at the base of the Martin. This limestone formation has been rather extensively investigated in the past and there are many known sample localities. For this work, the isopach map was drawn by computer to insure more objectivity and, in addition to the available data points, a number of dummy points with a zero value were added around the assumed form-

Jan 1, 1971

By Marilyn Biviano

(l)The direct economic costs to this nation resulting from a decision to embargo South African strategic and critical minerals imports are estimated at $1.85 billion per year.2,3 About 94 percent of these estimated costs are for two platinum-group metals (PGM's), platinum and rhodium. The estimated costs of a 5-year embargo beginning in 1988 for the strategic and critical minerals analyzed are presented in Table 1.4 (2)There are sufficient alternative world sources to South Africa for manganese, chromium, palladium, titanium, and vanadium to meet U.S. industrial demand in the event of an embargo. (3)Alternative world sources to South Africa for platinum and rhodium cannot meet U.S. industrial demand. Non-South African world supply sources can meet about 40 percent of domestic platinum consumption requirements and 50 percent of rhodium requirements. (4)As a result of the increase in prices for platinum and rhodium during the embargo, expansion of domestic platinum-group metals mining and secondary production is expected. During a five year embargo, domestic primary and secondary production expand and together satisfy about one-third of U.S. platinum requirements, one-third of U.S. rhodium requirements, and over one-half of domestic palladium requirements.

Jan 1, 1988

By Louise Pearce

?Environmental and social impact assessments (ESIAs) are: ??process-driven and scientific processes ??The process entails a number of steps and procedures which result in obtaining a licenceto operate ?and moving more towards a social license to cooperate. ?However, the primary premise of ESIA is to facilitate the consideration of environment and the communities in planning and decision-making which would ultimately make it possible to arrive at decisions that are ?sustainable?. ?Hence, ensuring the development of the mining sector on a sustainable basis is a critical challenge that needs to be addressed by the global community.

May 1, 2011

By Herman O. Ankenbruck

Analyses of statistical data indicate that haulage accidents are one of the largest sources of injuries and fatalities in underground coal mines, and that the rate of accidents in transportation has been increasing during the past few years. These previous analyses were performed by correlating accident or fatality data at a rather high level of miner activity. In this present investigation, underground surveys were made by observing conditions and activities in some detail at a rather low level of activity in an attempt to understand factors contributing to hazards in the specific situations observed. The aim of the current study was to derive preventive measures that might obviate the hazardous conditions and unsafe acts observed; and, following this, to provide recommendations for additional research and development to reduce accident potential in underground transportation. The major project tasks are diagrammed together with the task outputs in figure 1-1. Initially, a preliminary study of ell underground haulage operations was performed in order to establish the kinds of data needed and to provide the rationale leading to the data requirement. At the same time, the various types of haulage equipment used for each operation were defined. A preliminary analysis of each type of haulage operation was performed in order to establish the sequence of tasks required to operate haulage equipment. These tasks were transferred directly onto observation forms, and were used in developing interview forms. In parallel with the task analysis, a review was made of accidents and hazards that might occur during each type of operation.

Jan 1, 1975

By Holger Witthaus

Various seam conditions had been examined during longwall production at RAG German hard coal mines. Based on the field data a prediction method was developed considering separation planes as influencing factors for roof falls at the face. The characteristics, orientation, and density of separation are important factors on the occurrence of roof falls. In addition to geological influences, the performance parameters and geometry of support must be considered and optimized for the prediction and prevention of roof falls in a longwall face. Based on detailed macro- and microscopic investigations of e coal seams considering various ranks of carbonization, the origin and characteristics of separation planes are determined and a strata-specific influence on roof fall is interpreted. It was assessed that the coal face fracturing and displacement caused by the stress depend on the floor and roof strata conditions due to activation of the existing separation planes. Field studies are shown giving an idea of influences by advance rates of the longwall face, support delay and hydraulic pressure to the roof control in longwall faces in depth of more than 3000 ft. The analysis includes the application of specific software developed for longwall roof fall prediction as a result of a European research project. The software allows a laminar graphic display of roof fall probability, which is used for recognition of risk areas and risk management.

Jan 1, 2009

By K. Burke, G. Zhan, A. Mayer

A cover with capillary barrier effects (CCBE) is being constructed on the AA Leach Pad at the Barrick Goldstrike Mine site near Carlin, Nevada. The purpose of the cover is to eliminate/minimize infiltration of meteoric waters into the leach pad. Laboratory and numerical analyses indicate that Carlin Formation siltstone (TCS), a locally available material, has the necessary hydrologic characteristics when placed on the leach pad to act as a CCBE. A pilot study has been conducted on a small-scale test cover placed on the AA Leach Pad to examine the cover performance under irrigated conditions. The preliminary test results demonstrate that the designed cover is capable of preventing meteoric water infiltration.

Jan 1, 2001

By Pedro Máximo Ángeles

El presente texto señala el proceso «Strategic-Udy Modificado Angeles» utilizado para la producción de fierro o semiacero en Chimbote, Ancash. En ese sentido, durante la producción de aceros, es opcional el uso de fierros secundarios en la fundición (Scrap). La gran flexibilidad que ofrece el proceso permite producir tan bajo tonelaje sin sacrificar el costo de producción por tonelada de metal. Asimismo, las reparaciones pueden hacerse con gran facilidad, quitando la alimentación, drenando el horno eléctrico y cortando la corriente. Se puede operar el tonelaje deseado en una planta ya instalada con un pequeño descenso en la eficiencia. Por ello, es el método más adecuado en los lugares donde no se dispone de coke, tal es el caso de Chimbote - Perú y en donde se dispone de energía eléctrica barata, y de carbones que requieren procesos caros para su coquificación.

Nov 1, 1963

By Anatol Wojtowicz

This research program was conducted to determine if respirable coal dust emanating from a continuous mining machine can be suppressed more effectively by a high expansion foam than by the water sprays conventionally used. A high expansion foam system was developed and tested on a continuous mining machine under actual operating conditions. The utility of the system was demonstrated. Test results tend to show that foam application is more effective than water sprays in suppressing respirable coal dust. However, because of the extreme variability of the test conditions, scatter in the sampling data, and other factors, not enough data was obtained to form a firm conclusion that foam is more efficient than a water spray in suppressing respirable coal dust. Sufficient statistical data was obtained, however, to indicate that foam is more efficient than water in suppressing total float coal dust.

Jan 1, 1974

By Israel Huapaya, Juan Crisostomo, Dalia Valladolid

En el presente documento se describe la metodología utilizada para optimizar los procesos de extracción de muestras de roca sólida mineralizada con contenidos de oro correspondientes a un conjunto de vetas en interior mina, incluyendo la optimización del muestreo de fragmentos de roca mineralizada descargada en canchas

Sep 30, 2022

By John R. Rhodes

The objective of this project was to investigate the feasibility of analytical techniques potentially capable of determination of Mg, Al, Si, S, Ca and Fe in 1 to 2 mg samples of respirable coal mine dust, in a total analysis time of not more than 10 minutes per sample, using equipment capable of being truck mounted for field-laboratory operation. It was not essential that the technique be non-destructive, but the chosen technique is, and this enables the analysis to be performed directly on the 37 mm diameter membrane filter on which the respirable dust sample is normally collected. The sensitivity requirements are therefore quoted in terms of the units of measurement, µg/cm2. The detection limit (3o of the background criterion) should be 0.5 µg/cm2 or less. The precision should be 5% or better, at concentrations above which the detection limit is not the determining factor.

Jan 1, 1972

By Louis Schaffer

The objectives of the research were to determine whether a model health and safety program could be defined in terms which would enable its application to mines of all types, and, if such a model program could be defined, to determine through evaluations in two mining companies whether it would achieve measurable improvements. Volume 1 describes the model, how it was applied in the field and how it was evaluated. This, Volume 2, describes the literature and field research that preceded the model definition.

Jan 1, 1983

By G. G. Gold

A leach pad’s fluid flow characteristics greatly affect the recovery of metals from heap leaching. However, because there are other factors such as particle size distribution, application rate and method, and chemical reactions to consider, mining companies often overlook potential problems associated with fluid flow until it is too late. In an effort to better understand the dynamics of fluid flow in leach pads, a series of experiments were preformed using temperature probes. A model leach pad was set up using a particle size distribution, fluid application rate, and application method common to modern leaching methods. Variable water temperatures were applied in succession and data gathered from the three dimensional grid of temperature probes built in to the model. Current work is analyzing these data along with visual observations of the model, computer simulations, past mining experiences, and other related research, in an attempt to develop a low cost test that could be performed prior to large scale leaching to determine the fluid flow characteristics of a particular ore. This paper will summarize the work and findings to this point as well as suggest areas of additional related research.

Jan 1, 2004