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By W. Lee Daniels

Significant deposits (> 4,000 ha) of heavy mineral sands were discovered in the USA Coastal Plain of Virginia and North Carolina in 1989. The majority of these lands support highly productive row crop agriculture, and the development of restoration protocols that would return these lands to agricultural use was deemed to be critical to the long term sustainability of mining operations. Virginia Tech worked closely with all stakeholders to develop appropriate restoration protocols and to coordinate their implementation. Full-scale mining operations at the Old Hickory Project in Virginia were initiated in 1997 by Iluka Resources Inc., and restoration protocols have continued to evolve in response to a variety of economic, technical, and social issues. Approximately 750 ha of land are in various phases of backfilling and final reclamation. Return of these lands to agricultural row-crop production has been complicated by lateral variability in mine soil physical conditions, excessive compaction, and limited topsoil return. However, within the past two years, a series of tailings deposition and soil reconstruction practices have been developed and implemented that significantly improve post-mining soil productivity. Deep ripping and appropriate use of organic soil amendments have been particularly effective at restoring post-mining soil productivity.

Jan 1, 2005

By Todd Minoski, Matthew McElhinney, Mark Mazzella, Morgan Sears, Craig Compton

The National Institute for Occupational Safety and Health (NIOSH) is staffed with Engineers, Geologists, and Field Technicians conducting a variety of ground control research. The mission of the ground control teams within the Mine Systems Safety Branch (MSSB) is to eliminate ground failures leading to mineworker injuries and fatalities. Advancing the science behind ground control relies heavily on conducting mutually beneficial research at participating mines which is detailed in specific references throughout the paper. The ground control teams have several types of field instruments at their disposal to measure the ground response in underground mines. These include borehole pressure cells (BPCs), vibrating wire stress meters (VWs), hollow inclusion cells (Hi-Cells), roof and rib extensometers, load cells, and convergence meters. These instruments are used to measure changes in pressure, strain, and displacement within the underground environment. Instrumentation data is collected automatically using intrinsically safe or MSHA permissible dataloggers if required. Information is transmitted to the dataloggers using approved cable to distances of 200–1,000 ft. depending on the type of datalogger being used. Once mining is completed, the dataloggers are retrieved and brought to the surface, providing in-mine data to mine management and engineers for the conditions currently being encountered in a particular mine. This data, in conjunction with geologic data and stress mapping, can be used to validate numerical models. The practical application of these models is extremely important for mine management and engineers, particularly when faced with more challenging mine environments. Insight gained from applying these models can be used to make better engineering-based judgments for areas that will be mined in the future. The impact of such applications can result in a reduction of ground-fall accidents and injuries as well as generally safer working conditions.

Feb 1, 2024

By Tsuyoshi Adachi

Photovoltaic (PV) system is especially taken notice as one of important renewable energy resources, because PV has potential to provide a certain amount of energy supply as well as without greenhouse gases emission. Considering recent rapid increasing demand for PV system, more expansion of PV system is expected in the future. However, some precious metals and minor metals such as silver, indium and others are used as component materials of solar cell in PV system. Even if energy supply would become renewable, strict limitation of these metals still remain because amount of natural resources and recycling of metals has restrictions intrinsically. The aim of this study is to reveal the possibility of materials supply restrictions for Photovoltaic system quantitatively and to propose several measurements to assess supply risks for materials. Especially, silver supply potential which is used as wire line in PV system as well as PV demand forecast to estimate material use in the future are focused on. We divide underlying supply risk into 5 measurements and analyze them by time series, i.e. price volatility, resource potential, recycling ratio, production type and supply concentration are investigated. Comparing these factors of silver with other metals, the potential of silver supply for PV is presented. In addition to it, we propose another method to quantify country risk applied an insurance pricing model in finance pricing theory and combine it with the supply concentration measurement. As a result, supply risk of silver will increase gradually in the near future because of its resource constraints and supply-demand balances although silver market is sufficiency competitive one. From the country risk analysis, Peru is not only a significant supply country but also has the highest country risk. Some higher risk countries will increase the level of supply risk even if the concentration ratio of supply indicates moderate level.

Aug 1, 2013

By Y. Shu, A. R. Laplante

"A laboratory Knelson Concentrator (LKC), 7.5 cm in diameter, was used to study the performance of a similar unit at plant scale, 76 cm in diameter, This paper reports on sampling and assaying procedures and problems, and discusses the performance of the plant unit.The sampling procedure was based on the extraction of large samples, 5-15 kg, and their complete processing with a LKC, to characterize size-by-size performance. The procedure yielded reliable estimates of overall gold assays, after blatant assaying errors were corrected. The plant centrifugal unit concentrate was sampled in situ, which yielded very erratic grades, with a large overall negative bias. Due to the very heterogeneous nature of the concentrate, which can be linked to flow patterns in the riffles of the unit, it is recommended that for future testwork, the concentrate be recovered separately, blended and then sampled.The plant centrifugal separator, when operated at a feed rate of 25 t/h, yielded total and free gold recoveries of 41 % and 62%, respectively. This is much lower than previously reported data, and suggest that at 25 t/h, the unit is overloaded. However, recovery did not decrease with time over a loading cycle of 2 hours, which suggests that present loading cycles, generally 1 hour, can be significantly increased. INTRODUCTIONThe study of gold gravity circuits is plagued with the statistical problem of determining the behaviour of particles occurring with a very low frequency. This problem becomes particularly acute with increasing particle size. For example, considering the average weight of a gold flake in the 840-1200 µm (20/28 mesh) to be about 5 mg (Banisi et al, 1991), a reasonably high grade feed of 10 git would require, for a relative error (standard deviation) of 10% on grade, 100 particles, that is 0.5 g of gold, or 50 kg of 840-1200 µm material (a Poisson distribution is assumed). Gy's formula, for the same data, yields a weight of 33 kg, with a shape factor of 0.1 and a size distribution factor of 0.5. Both results are comparable; to obtain the suggested weight of material, a stream containing 5% weight in the 840-1200 µm would require 1 tonne samples (of unsized material). The problem rapidly disappears with decreasing particle size. Still with Banisi et al's data, a gold flake in the 300-420 µm range averages 0.5 mg in weight; the same 10% error on grade corresponds to a weight of 5 kg. Gy's formula for the same size distribution and particle shape factors as above predicts a required mass of 1.4 kg. This would correspond to an unsized sample weight of 10 kg with 14% weight in the 300-420 µm, for example."

Jan 1, 1992

By R. P. Goel, P. N. Chaudhary, R. K. Minj

The bulk of high carbon ferromanganese produced in India continue to have more than 0.35% phosphorus since they are produced by carbothermic reduction process. The low phosphorus manganese ores are depleting fast and ferromanganese manufacturers will have no option but to use medium and low grade ores having high phosphorus content resulting in high phosphorus in the product. A systematic study was taken up at NML to solve this problem. Initially, a thermodynamic analysis was carried out for which Ba-P-O ternary predominance diagrams were constructed at several temperatures to predict the most suitable conditions for selective removal of phosphorus from high carbon ferromanganese. These conditions required a usage of a flux having a high level of basicity, moderate oxygen potential as well as low melting temperature. The experimental results showed that it was possible to remove phosphorus from high carbon liquid ferromanganese from 0.56%to 0.18% using BaCO3 based fluxes at the rate of 16-wt% of the ferromanganese charged. However, the Mn loss varied in the range of 2-5%. The objective of the subsequent study carried out at the laboratory scale was to optimize the flux consumption as well as minimize the Mn loss with effective dephosphorization by using BaO based calcined pellets instead of BaCO3 based powders. It was felt that the handling of pellets under plant conditions would be easier and also eliminate the loss of flux as a dust, which occurs when powder is added. These pellets were forced towards the bottom of the melt for better efficiency. For this purpose, a plunging system was designed and fabricated in-house that helped in reducing the flux consumption to less than 5% and also improved the kinetics of the process. The desired results were achieved within 10 minutes of the addition of the flux. The know-how is ready for transfer to interested parties and authors are willing to conduct large scale trials with them.

Jan 1, 2007

Reduce the number of accidents in which large mining trucks crush objects that were not visible to the driver. Approach Improved rear view mirrors, light-bending plastic lenses, and a closed circuit TV, are combined in a rugged system that allows the driver to see almost all areas around a large raining truck. How It Works Improved mirrors, used in place of ordinary left and right rear view mirrors, give wider angle viewing. Fresnel lenses, two mounted on the front edge of the hood and another one mounted above the right front fender, show objects close to the front and right side of the truck. A rugged closed circuit TV camera mounted above the rear axle reveals objects behind the truck. See diagrams showing reduction of blind area around a 150-ton mining truck. The improved mirrors for rear viewing are approximately rectangular. The left rear view mirror has a flat reflecting surface 10 inches wide by 20 inches high. The right rear view mirror is curved to give wider viewing angles, both from left to right and up and down. This mirror is 12 inches wide by 16 inches high. Its convex reflecting surface has the same curve as the surface

Jan 1, 1979

By Zetti Gavelán

Lack of skilled workforce in mining industry during the current decade has been a serious concern for most mining organization globally. At the beginning of this decade the major envisioned difficulty was related to generational breach of mining professionals. By 2003, mining industry recover from a low metal prices cycle following by a worldwide mining investment boom in 2005 that triggers a talent war among mining companies that was not only limited to professional level but skilled operators as well. Despite world?s economy collapse in October 2008, impact on mining industry was small comparing to other industries and appears to show evidence of healing. Under this context, fundamentals that have been driven lack of skilled workforce for the mining industry in previous years still valid. Starting in 2007, Minera Argentina Gold SA - Barrick Veladero, subsidiary of Barrick Gold, initiated an innovative selection and training program for candidates without exposure to mining. Following our corporate social responsibility mandates, Barrick Veladero decided to change its hiring process entirely, concentrating on selection and training of local people with no experience rather than hire experienced mining operators. This paper shares Barrick Veladero experiences on its hiring program, challenges faced, and current results.

May 1, 2010

By P Craig, A Crosky, P C. Hagan, E Elias, B Hebblewhite, S Saydam, D Vandermaat

"Premature failure of rock bolts has been recorded at twelve underground coalmines over the past 15 years in Australia. Over the last four years, UNSW Australia has been conducting an Australian Research Council (ARC) and Industry funded linkage research project into premature failure of rock bolts. The extent of the problem was investigated by underground surveys of mines with known prematurely failed bolts using visual mapping, non-destructive load and ultrasound testing. A major component of this project was to define the environmental factors responsible for corrosion of rock bolts. The environment to which a rock bolt is exposed will include groundwater chemistry, the mineralogy of the strata, atmosphere within the drill hole and even microbial activity. This paper focuses on the groundwater survey and analysis findings to date along with in-hole bolt corrosion coupons installed into field sites. Corrosivity classification systems exist for general corrosion but do not apply to the rock bolt stress corrosion cracking (SCC) problem found in Australian underground coal. The method of in situ investigations is leading towards the building of a corrosivity classification model to assist mines in prediction of premature rock bolt failure. An ‘in-hole bolt corrosion coupon’ development by the project may have multiple benefits of: helping quantify any corrosivity classification system providing an in situ ground support corrosion monitoring tool for testing possible corrosion protection solutions.CITATION:Craig, P, Saydam, S, Hagan, P C, Hebblewhite, B, Vandermaat, D, Crosky, A and Elias, E, 2014. An investigation of the corrosive impact of groundwater on rock bolts in underground coalmines, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference, pp 277–286 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 5, 2014

By Éverton Rafael Breitenbach

A liga MA2024, reconhecida pelas aplicações em componentes aeronáuticos e automobilísticos, foi obtida por moagem em moinho atritor. Com o objetivo de melhorar as propriedades mecânicas, adições de 2,5%; 5%; 10% e 20% de reforço com tamanho de partícula inicial menor que 45 µm foi realizada em moinho planetário, com relação de carga:bolas de 3:1 e 15 minutos de moagem a 250 RPM. A consolidação dos corpos de prova cilíndricos foi realizada pela técnica de forjamento de precisão, em matriz fechada em forno tubular na temperatura de 490oC. A microestrutura foi avaliada por microscopia óptica e eletrônica, enquanto que a resistência mecânica foi avaliada por ensaio de microdureza. Os resultados de microscopia revelaram a formação de intermetálicos que influenciam de forma positiva e significativa no comportamento mecânico dos compósitos.

Aug 7, 2018

By Kristineq Pankow

The August 2007 Crandall Canyon mine disaster raised national awareness of mining-induced seismicity (MIS) in Utah as well as general interest in how seismic monitoring might improve mine safety in the region. Unlike the situation in most other mining areas in the U.S., local seismographs in Utah?s Wasatch Plateau (WP) and Book Cliffs (BC) coal fields are an integral part of a modern real-time earthquake information system developed by the University of Utah Seismograph Stations (UUSS) as part of an Advanced National Seismic System. The UUSS earthquake catalog contains a continuous record of MIS at all active mine sites in the WP-BC region since 1978 (more than 18,000 seismic events = M 4.2). We describe characteristics of MIS and current seismic monitoring capabilities in the WP-BC region. We then demonstrate, using MIS from an example Utah coal mine, the ability to refine event locations with estimated absolute errors of ~200 m or less using a combination of (1) a double-difference relocation methodology and (2) ground truth information provided by mine operators. This approach enables sufficient spatial resolution to correlate MIS with mining activities, providing a useful tool to help improve mine safety.

Jan 1, 2008

By A. C. Veatch

Jan 1, 1921

By Suresh K. Bhatt

This U.S. Bureau of Mines report reviews major developments in continuous haulage technology for underground coal mines. Haulage systems, both in use and under development, were investigated through a comprehensive literature search and visits to mines and manufacturers. The systems include flexible conveyor train, mobile conveyor, monorail bridge conveyor, multiple-unit continuous haulage, extensible, and belt turning systems. Strengths and weaknesses of the systems are assessed in light of their operating under remote control and their application to the computer-assisted continuous mining machine research being conducted by the Bureau. Through mining scenarios, candidate haulage systems are conceptualized to be consistent with the capabilities of the mining machine.

Jan 1, 1991

By P. R. Taylor

The ability to treat refractory gold concentrates that contain appreciable amounts of sulfur and arsenic, in an economic and environmentally safe manner is important to the gold mining industry. Processing alternatives include: autoclave oxidation, bacterial oxidation and roasting. Roasting may be the cheapest of all the alternatives if inexpensive methods can be found to contain the arsenic and sulfur. The research program, being reported here, has been evaluating the ability to use hydrated lime in the roaster to capture both the arsenic and the sulfur. Lime roasting is not a new idea, it was proposed for copper ores by Bartlett in the early 1970's (Bartlett and Haung 1973) and for cobaltite concentrates by Taylor in the early 1980's (Taylor et al., 1981). In addition, ores have been roasted that contained limestone and it was shown that partial capture of the sulfur was possible. Lime -sulfur containment has been proposed for the coal fired electricity industry, as well.

Jan 1, 1992

Flotation of Phosphate Gangue from Magnetite Fines - Non-Ionic Surfactant as Atrac Collector Modifier

Sep 13, 2010

By R. T. Jones

Base metals and platinum group metals can be collected in metallic alloy form, via a wide variety of smelting processes. The recovery, or degree of collection, of the valuable metals is a function of the extent of reduction in the furnace, which, in turn, is indicated by the fraction of iron present in the feed materials that report to the alloy. An equation has been developed that relates the recovery of various metals (such as Ni, Co, Cr, and PGMs) to the recovery of Fe. This recovery equation (for each metal) is characterized by a single parameter (K?) that can either be empirically fitted to the data, or expressed in terms of the equilibrium constant and the ratios of the activity coefficients involved. Data from a number of varied DC arc furnace campaigns are presented to illustrate this behaviour.

Jan 1, 2009

By D. G. F. Hedley, F. Grant

"In 1958, the Ontario Department of Mines appointed a committee to study the accident situation and mining methods used in the uranium mines in the E1liot Lake district. This committee reviewed the existing knowledge on mine design, pillar support and roof spans and came to the conclusion that scientific knowledge had not yet reached the stage of producing rational design procedures which would reduce the dependence on trial-and-error methods. Since that time, the Mining Research Centre has made numerous stress measurements in two mines to define the pre-mining and pillar stresses. A comprehensive series of tests has been done in the laboratory to measure the compressive strength of the rock; a geological survey of the region has been made to evaluate tectonic stresses; and a survey was done on mining conditions with regard to stable and unstable pillar configurations. This information has been used to evaluate pillar design as effected by pillar width and height, depth below surface, extraction and pre-mining stress fields. The resultant design of pillar widths and corresponding extraction as the depth increased is in line with past and present experience in these mines. The information available on roof stability is still insufficient to design stable stope spans with the same degree of confidence; experience and trial-and-error methods are still required."

Jan 1, 1972

By Wilbur L. Webb

This publication reports on the design, fabrication and test of an Improved methane monitor system for compliance to 30CFR75.313. The system will Initiate automatic shutdown of mining machinery when excessive concentrations of methane are encountered. The prime consideration: In the design were small size, Improved accuracy and reliability, fast response and a transient resistant power supply capable of reliable operation from any mine power source. The power supply contains an internal battery that provides operating power to the detection system prior to mining machine start-up or after machine shutdown. This report documents the development program from conception through in-mine testing.

Jan 1, 1978

By C. Schlumberger

INTRODUCTION The object of the present paper is to discuss, from a geological point of view, the practical results obtained by the authors with the method of the 'resistivity map of the subsoil' in the study of various mining problems. Some of the studies described date from 1920, 1922, and 1923. They are, therefore, quite old, at least as far as geophysical research is concerned (1). Others, on the contrary, are very recent (2). We shall deal only very briefly with the theoretical and technical sides of the processes employed. This paper has, essentially, a practical purpose, and it has seemed unnecessary to enter into a detailed discussion of the methods. Such a discussion cannot be presented without introducing ,quite. Complex considerations both of mathematics and experimental physics, which interest only the geophysicist: whose work is highly specialized.

Jan 1, 1931

By R. J. Durrheim

The DEEPMINE Collaborative Research Programme was established to create the technological and human resources platform that would make it possible to mine gold safely and profitably at depths of 3 to 5 km. The DEEPMINE Programme has four goals: to acquire knowledge of and develop appropriate technology for new ultra-deep level mines, to stimulate education and training, to establish a culture of innovation, and to encourage rapid technology transfer and implementation. The research programme was launched in July1998 and will be completed in March 2002, with the final year focusing on the transfer of knowledge to the industrial partners. DEEPMINE represents a new model for conducting mining research: it is driven by industry needs; emphasizes collaboration between industrial partners, research organizations and tertiary education institutions; and has a novel joint-funding mechanism. DEEPMINE has employed a range of vehicles to transfer knowledge to its industrial partners. Novel aspects include: (a) electronic publication of Summary Reports and Guideline Handbooks that seek to consolidate the huge body of knowledge comprehensively and concisely, (b) a series of DEEPMINE Schools designed to enable industry practitioners to apply the knowledge to their current work situation, and (c) Consultancy Reviews, where DEEPMINE specialists seek to apply knowledge to specific real problems on mines.

Jan 1, 2002

By Douglas C. Corner

This is the first of a series of papers dealing with modern tunnel-driving methods, compiled in accordance with an outline prepared by engineers of the United States Bureau of Mines and to be published in a series of information circulars by the bureau. This series will supplement a similar and earlier series of papers dealing with mining methods and costs. ACKNOWLEDGMENTS The author desires to express hiss appreciation, of the assistance of A. C. Dennis, manager for the West Construction Co. Contractors, and Franc: E. Winsor, chief engineer for the Boston Metropolitan District mater Supply Commission who furnished much of the data and detailed description of operation appearing in the following pages. C. F, Jackson, mining engineer, United States Bureau of Mines, collaborated in the preparation and arrangement of the text.

Jan 1, 1931