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By George E. Niewiadomski

The exposure of miners to radon gas and its airborne daughter products is a serious health problem which has long been recognized in the uranium mining industry. The association of high exposure to alpha particle emitters with incidence of lung cancer is well established. There continues to be a pressing need to reduce and eventually eliminate the high incidence of occupational lung cancer among uranium miners through the development of new and improved measurement and control technologies. This paper highlights the current efforts of the Bureau of Mines radiation hazards research program. It is aimed at obtaining a fundamental understanding of the behavior and transport of radon and radon daughters, developing more accurate and reliable instruments and measurement methods and developing cost-effective control techniques. Also discussed are the most recent accomplishments and the future research plans of the program.

Jan 1, 1981

By Surendra K. Mishra

Metallic and oily components are the major contaminants of industrial wastes. Underground burial and incineration have been the commonly practiced methods of waste management. To provide a relatively more permanent solution, different processes have been developed. In addition to reviewing these processes, potential of using flotation as a process to treat hazardous metal and oil contaminated wastes is discussed in this paper.

Jan 1, 1989

By T. Ko, K. N. Han, C. S. Park, N. S. Kim, C. Yoon, H. Yoon

Quantitative analysis of Platinum Group Metals from ore samples and industrial materials using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS), Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), Atomic Absorption Spectrometer(AAS), and X-ray Fluorescence (XRF) techniques was conducted and the performance of various techniques was compared. The effects of different matrices in the sample materials were compared and discussed for each analytical technique. The ICP-AES technique exhibited better accuracy than AAS but showed limitations in its application due to strong spectral interference in the presence of common matrix elements such as iron. The ICP-MS showed the lowest detection limit and less spectral interferences than the previous two techniques. The XRF technique was also applied to examine the total amount of PGM from industrial materials. Results from each analytical method on various sources were presented and discussed.

Jan 1, 2003

By William F. Eichfeld, Robert J. Wenzel

INTRODUCTION The phrase "subsidence control planning" can refer to the use of specific mining methods and-specialized techniques to control subsidence events or it can refer to planning for subsidence by predicting its magnitude and timing and further planning mitigation strategies. In the first case the objective is actually subsidence prevention while in the second it is a design procedure that seeks to maximize the use of both surface and subsurface resources. Neither technology is well developed at this point. The purpose of this presentation is to briefly outline the Department of Energy's Subsidence Program. This program is, in general, bases on the premise that subsidence control technology, by any definition, can be accomplished only through a thorough and rigorous understanding of subsidence phenomena. This understanding must come from many well planned and executed studies of stress redistribution and strata deformation as they occur during mining activities. There is presently considerable incentive to improve our subsidence engineering capabilities due to the desire for increased coal utilization with acceptable environmental impact. Considerable research in this area is being sponsored by federal and state governmental agencies, universities, and the coal industry. Federal sponsorship has been borne by the Department of Energy, the Bureau of Mines, the Office of Surface Mining and the U.S. Geological Survey for the most part. These agencies have carried out basic research in their laboratories and have contracted with other organizations for additional work. At this time most of the available resources are directed toward contract research, especially in DOE. It is the DOE research plan which will be addressed here.

Jan 1, 1982

By R. Bruno

The problem of testing different production strategies has been studied in relation to reserves selection and a computer programme for ore production management has been developed. The case study presented concerns an underground rock salt mine in Sicily with different product lines and variable ore characteristics. A geostatistical block model of the deposit was constructed on the basis of the physical and chemical parameters that ultimately determine the type of end-product in operations according to different selection strategies were simulated using the model and taking account of both technical and 'commercial constraints. The structure of an ore production management programme running on a PC to select both the mining unit and the end-use of the ore is described.

Jan 1, 1989

By Ishwar G. Mulani

In conveyor design, the first step is capacity and the second step is belt width and speed. The third step is decision on 'ff," where distinction arises between DIN/ISO and CEMA for calculating resistances. Then again, both the methods are virtually similar. This topic helps in understanding Dm design style and its comparison to CEMA. This topic is from the book Engineering Science and Application Design for Belt Conveyor wherein the issue has been analysed in detail. It presents a workable calculation model to calculate the value off in design office, based on conveyor parameters. CEMA uses Kx, Ky and 0.01 5 instead off. Thus, f is a sum effect of Kx, Ky and 0.015. Hence, knowledge on f is also applicable to Kx and Ky. This helps to understand their relationship.

Jan 1, 2004

By F. Soumis

This paper describes an integrated procedure for the very short term production planning of an open pit and the execution of this plan: the truck dispatching. Integration of plan and dispatch means that the plan is realistic so that its objectives can be realized by the dispatch. This realism is obtained by supplying the plan optimization, which involves mixed integer programming, linear programming and non-linear programming, with experimental O.R. models of waiting and blending. The arrangement of these models in the computer programm has made it possible to obtain very short computing time for the planning in spite of the width of the optimisation. The dispatching of a truck is made by solving a classical assignment problem for each dispatch over a horizon of the expected*next 10-15 trucks to request dispatches. This deep-reaching dispatch procedure uses the continuously arriving information about trucks' positions and shovels situations and models by probability functions the expected waiting time of shovels and trucks. In this manner trucks and shovels are synchronized and last moments' opportunities for productivity gains can be obtained. The dispatch procedure takes .5 second on PDP11. This integrated planning and dispatch procedure gives high productivity while ensuring good blending. Results from the Mount Wright mine of the Quebec-Cartier Mining Co., where the integrated procedure has been installed on the existing computer equipment PDP11, are included.

Jan 1, 1989

By Stanislaw Nawrat, Waclaw Dziurzynski

An increasing concentration of coal production, especially in the circumstances of intensive methane inflow makes the coal mine managing staff apply new techniques of safe mining. It paves also the way for scientists to develop new directions of investigations and implementation of state-of -the- art technical solutions. Simultaneously, it could be noticed that the funds assigned for expansive 'En situ ' investigation are continuously decreasing. Better and better results are reached when applying computer technique in calculations of the parameters of ventilation process. Recent theoretical and experimental investigations of air and gas (methane) flow in longwall areas with caving, combined with the implementation of methane drainage system allowed to create, a mathematical model and consequently to elaborate a computer supported numerical simulation of discussed phenomena. The mathematical model has been modified and the simulation program was prepared in such a way that the software is convenient for a user looking for an optimal solution. The paper presented the methodology of optimal choice of following parameters: - ventilation system - rate of flow through the wall. The procedure takes into consideration keeping a safe level of concentration methane in air flowing through the longwall as well as the criterion of maximum methane concentration within the methane drainage pipe line. Results of variant computer simulation regarding the longwall with caving are shown in graphs and tables.

Jan 1, 1995

By Gerald G. Griswold, Allan G. Provost

"To Sink or Not to Sink"; this play on the Bard's words sums up the considerations and problems that face the owner on every potential shaft sinking project. The growing demand for access into the earth is pressing construction into new areas and to greater depths. The following discussion will entertain some of the effects of these new and unknown aspects upon the approach to designing and sinking of deep shafts. We will also look at the current shortages of equipment, materials and skilled manpower, and their effect upon the planning and sinking of shafts. Particular emphasis will be placed upon equipment selection, and we will discuss how economics, while always a prime consideration, is now, more than ever, both an incentive and a detriment to the industry. FUTURE CONSIDERATIONS Shaft construction is assuming ever increasing importance both in mining and civil endeavors. The rapid depletion of near surface mineral reserves is requiring the mining industry to look deeper into the earth for new sources. These greater depths increase the exposure to unfavorable geological conditions; heavier ground, high water pressures, and high temperature. South African gold mines have now reached depths of 12, 000 feet, where the rock temperature is 1380 and water bursts from the fissures. In North America depths to 7, 500 feet have been sunk, but deep shafts are still generally considered to be those of

Jan 1, 1974

By Michel Grenier, Gopal Kunchur, Stephen Hardcastle

This paper presents the findings of a dust study in a typical fluorspar processing plant. The primary purpose of this study was to identify employees and occupational groups exposed to high dust levels and determine compliance with personnel regulations for regular and extended work shifts. The range of airborne concentration of respirable silica and fluoride compounds in specific areas and on personnel was determined. State of the art dust monitoring equipment and tracer gas techniques were used to measure dust concentration, pinpoint dust sources and map major airflow trends in the mill. Results of the survey indicated silica dust concentrations in excess of permissible limits being produced mainly by crushers at the south end of the building. Tracer gas releases and gas chromatographic analysis further showed that prevailing south to north air currents tended to carry and spread dust produced by the crushing operations throughout the process plant. Airborne concentrations of fluoride compounds measured during the study were always well below the prescribed threshold limit value (TLV) for the contaminant. Recommendations, including a mechanical exhaust ventilation system on crushers and transfer points, scheduled preventive maintenance on existing bar sprays and wearing of personal protective equipment were made which significantly improved the work environment. Further testing conducted after Installation of the dust extraction system revealed significant improvements in most areas of the mill.

Jan 1, 1991

By Joseph M. Denk, Gary J. Wirth

This paper summarizes a three phase face ventilation study which was conducted from September 1989 through March 1990 to determine face area methane liberation patterns on two extended longwall sections. The coal seam being mined was considered gassy and the mine liberated an average of 14.4 million cubic feet per day (cfd) or 0.41 million cubic meters per day (cmd) of methane through the mine fans. The mine also used an extensive underground degasification program to recover up to 13.4 million cfd (0.38 million cmd) of methane. Data was collected while the longwall sections were mining from the beginning, middle and end of panel extraction to determine the relationship between the methane liberation and extent of longwall retreat. As expected, methane concentrations did increase from the headgate (intake) to the tailgate (return) side of the longwall face and peak concentrations were detected above the shearer as it passed a methanometer location during mining. There were significant differences in the methane liberations due to the location of the active face within the longwall panel. Results from this study could be used to determine a minimum design face air quantity for an extended longwall section operating under similar conditions.

Jan 1, 1991

By Stephen R. Pogorski, Nicholas Busigin, Colin R. Phillips

The movement of radon away from its source in porous media is determined by two key parameters: the fraction of the total radon formed which enters the intergranular pore spaces, termed the emanation coefficient, and the transport processes which exist in these pores such as diffusion and convection. The first parameter, the emanation coefficient, is of primary importance since it is a measure of the actual amount of radon which is free to migrate within the media. The effects of particle size and radium concentration on the emanation coefficient were examined using a quartz-pebble conglomerate ore from the Elliot Lake mining district of Ontario. It was found that the smallest particle size examined (<74 µm) had the highest radium concentration and contributed the most to the radon emanation. A one-to-one correspondence between radium concentrations for the various particle size fractions and radon emanation was not observed. Samples were examined using scanning electron microscopy and very small particulates were observed to be present on the particle surfaces. When these very small particulates were removed from the host particle surfaces by rinsing, the radon emanation decreased by a factor of 17. This result indicates that most of the emanation comes from the very small particles. The effect of moisture on the emanation coefficient was examined qualitatively and a trend of increased radon release with moisture content was noted.

Jan 1, 1981

By M. E. Rossi, V. Camacho

Reconciliation of production information is critical to evaluating the effectiveness of predictive models that would allow for the optimization of mining operations. Whether mining open pit or underground, mine-to-mill reconciliations can be one of management&apos;s better tools for the performance of proper accounting. Such reconciliations can also be a very useful tool in evaluation and optimization. This paper proposes a set of criteria and objectives for a typical reconciliation program. This paper also presents a stepwise, logical approach to performing reconciliations and discusses the benefits associated maintaining good information. It also highlights some of the potential pitfalls involved and the methods used to avoid collecting misleading information. These issues are illustrated with an example of a model-to-mine-to-mill reconciliation program that is being implemented at an operating mine. The program involves multiple predictive models (long-term and short-term block models), feed from three open pits and one underground mine, in addition to intermediate stockpiling, for a total of 23 mill streams. This paper presents a summarized version of this reconciliation program and its initial results as implemented at Minera Michilla S.A.

Jan 1, 2000

By S. R. Bryan, J. D. Stephens, D. R. Rothbard

The distributions of gold and associated elements in mineral grains from a pyritic gold ore were studied by optical microscopy, and by SEM and SIMS imagery. Products studied were a sulfide flotation concentrate, a calcined sulfide concentrate, a cyanide leached calcine, and a cyanide leached pressure oxidation residue. Individual pyrite grains are compositionally zoned and solid solution gold occurs in some, but not all zones. Most of the gold in calcined products is present as metallic coalesced grains that are smaller than 100 angstroms. Gold lost into cyanide leached residues from the calcines tends to be in “semi-dense” grains that cannot be distinguished from gold-free grains except by SIMS analysis. The gold in cyanide leached pressure oxidation residues occurs as solid solution gold in unoxidized pyrite remnants.

Jan 1, 1990

By L. G. Austin

The general manner in which the liberation function must change during size reduction is described. Data from float-sink (washability) analysis of a coal is used as an illustration, and a Locking Index is defined and calculated. Ash is not distributed equally with respect to sieve size but is concentrated more in the finest sizes. On the other hand, the ash is less locked with coal in the finer sizes than in the larger sizes. Further crushing showed decreased locking in intermediate sizes, but the material in the fine sizes (produced from breakage of highly locked larger sizes) was more locked than material of the same size in the feed. Future work is also discussed.

Jan 1, 1995

By T. D. Rourke, E. J. Cording, O&apos

INTRODUCTION Detailed investigation of a 60-ft-deep excavation in a mixed profile of sands and stiff clay was performed by the University of Illinois for the Washington Metropolitan Area Transit Authority (METRO). The work was coordinated through DeLeuw, Cather and Co., the General Engineering Consultant of METRO. Instrumentation was concentrated in a portion of braced excavation for the Gallery Place Station near the intersection of 7th and G Street. The early construction date, the 60 ft depth of cut, and the proximity of large buildings formed the basis for selection of this site as the focal point of observation and measurement. A history of lateral and vertical displacement is provided wherein movements which occurred during excavation to the full depth of cut and, subsequently, during station construction and the removal of braces are described in detail. Observations of preloading and the consequent brace loads and wall displacements are described. The effect of temperature change on brace loads is discussed and the measured apparent earth pressure for the 60-ft cut is provided. The paper discusses the relationship of lateral displacements of the cut wall to the construction procedure, and compares the lateral wall displacement with both lateral and vertical movement in the surrounding soil mass. Based on observed movement, the method by which displacement was predicted for a nearby 82-ft-deep excavation is described. The performance of the 82-ft-deep excavation has been summarized elsewhere (2).

Jan 1, 1974

By W. A. Steingraber

This paper discusses the application of deep well disposal techniques to the problem of disposing of large volumes of low level radioactive wastewaters generated by the in situ uranium mining industry in Seth Texas. Data is presented on wastewater composition and volumes, geologic and hydrologic parameters of the disposal reservoirs, tell construction techniques, well operation, well monitoring requirements, and critical factors in evaluating the Safety and environmental impact of a deep injection well system.

Jan 1, 1980

By J. A. Brierley, C. L. Brierley, R. C. II Blake, S. McGinness

A principal long-term goal of this laboratory is to achieve a detailed understanding at the molecular level of the microbial-dependent solubilization of minerals. Three recent advances in this research are summarized. (i) An in situ electrolytic procedure is described whereby large quantities of autotrophic iron-oxidizing organisms may be achieved for fundamental or applied studies. Over 600 grams wet weight of Thiobacillus ferrooxidans were harvested from a single 55-gallon growth vessel. (ii) A basis is presented for classifying some 70 different iron-oxidizing bacteria into one of 4 categories, depending on the type of redox-active electron transport proteins expressed during aerobic respiration on reduced iron. Comparative spectroscopic analyses indicated that different electron transport mechanisms exist in different genera and species of acidophilic bacteria that respire on iron. (iii) A method is introduced to investigate the binding interaction between bacteria and minerals, based on changes in the electrokinetic properties of the two species. Preliminary experiments indicated that the electrophoretic mobilities of pyrite and Thiobacillus ferrooxidans were both altered when the two colloid particles were mixed prior to the actual electrokinetic measurement. The need for more basic information regarding all aspects of the microbial-dependent solubilization of minerals is evident.

Jan 1, 1993

By Joseph Renk, David Akers, Glenn Shirey

Each year, US coal cleaning plants landfill or impound millions of tons of high-quality, fine-sized coal. This coal is not only difficult and expensive to capture during cleaning, but, if captured, can pose serious materials handling problems. The GranuFlow. Technology was developed and patented by the U.S. Department of Energy (DOE) to address these problems. GranuFlow involves the addition of a coal binding agent such as an asphalt or heavy oil emulsion to coal to reduce moisture, dusting, and freezing and to improve the flow properties of the coal in bins and chutes (1, 2, and 3). When the emulsion is added before mechanical dewatering, the binding agent causes the formation of fine-sized coal agglomerates that dewater better than untreated coal. In addition, the binding agent increases the capture of ultra-fine coal in screen-bowl centrifuges. Previous work by DOE has also demonstrated that such treatment results in a significant reduction in dustiness and a reduced potential to freeze. To address concerns about the handling and combustion characteristics of GranuFlow treated coal, DOE performed a pilot-scale pulverization and combustion test (4). No problems were encountered during pulverization or combustion, and use of this fuel in a p.c. boiler was found to be feasible from a technical perspective. CQ Inc. has an exclusive license from DOE to market this technology and is currently performing a series of commercial demonstrations to determine if GranuFlow is both technically and economically viable.

Jan 1, 2005

By Michael J. Nicol

Hydrometallurgical processes involve the recovery of metals from ores, concentrates, calcines, mattes and scrap materials by a series of operations involving leaching or dissolution, separation, purification and reduction of metals in aqueous solutions. The underlying theoretical basis of many of these operations is electrochemical in nature and it is the purpose of this review to identify and illustrate, by way of examples from the author&apos;s experience and that of others, the central role of interfacial electrochemistry in the understanding, design and control of these operations.

Jan 1, 1993