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The last decade has seen the use of powerful computerized Mine-Wide Monitoring (MWM) systems for detecting hazardous conditions in underground coal mines. Recently, the U.S. Bureau of Mines and Jim Walter Resources, Inc. (JWR) expanded the scope of MWM system to include ground control. Single-point extensometers were installed in each of 30 intersections along a tailgate entry. These instruments monitored the rate of roof sag, a sensitive indicator of roof instability. Data were collected by the mine's own computerized MWM system. The paper describes the successful integration of ground control instruments into MWM, the data reduction procedures, and the identification of several hazardous areas.

Jan 1, 1994

By F. Grandjacques

INTRODUCTION Selective Reduction of Nickel in Oxidized Ores Oxidized nickel ores, either garnieritic or lateritic, contain much more iron than nickel. The regular carbon reduction in an electric furnace is operated in such a manner that the greater part of iron oxides is reduced simultaneously with nickel oxide, resulting in a low nickel content ferronickel. In order that the nickel content of residual slag may be suitably low, -excess carbon must be fed so that the carbon content of the ferronickel thus obtained is that of casting iron. The metal also contains other impurities such as silicon, chrome, etc. In order to convert the casting iron into slightly carburized ferronickel with high nickel content, the greater part of the carbon and more than half the iron contained therein must be oxidized by means of oxygen. Energy is thus consumed as carbon, and power to reduce iron oxides, and more energy is consumed as oxygen to re-oxidize the iron contained. This method can be economically adopted for nickel ores with grades ranging around 2. 5 to 370, but it gets excessively costly when nickel grade falls below these values. This is why, for nickel ores with low nickel grades and high iron content, studies were conducted to develop a selective reduction process which, while reducing only a small part of the iron oxide, would provide efficient reduction of nickel oxide. Rich ferronickel is thereby obtained, with nickel content ranging around 30 to 50%. Due to the presence of slag with a high iron oxide content, the metal thus

Jan 1, 1979

By A. Tobey Yu

The smelter is the heart of a copper producing operation. Its principal function is to reduce and convert raw copper concentrates and/or leach plant precipitates into blister copper before it is refined. In addition to concentrates and precipitates, typical feed to a smelter also encompasses matte chips, flue dust, flux and lime. By nature, the characteristics of these materials are extremely variable, ranging from sub-micron to lumps, from slurry to dust, from abrasive to corrosive and free-flowing to adhesive. Furthermore, as a result of geological formation, most of the world's open pit copper mines are located in a semi-arid zone, where precipitation is minimal. This particular climate compounds the problem of handling these materials.

Jan 1, 1976

By R. A. Jankowski

The U.S. Bureau of Mines has conducted a study to identify the sources of respirable dust and appropriate dust controls applicable to today's high tonnage longwall faces. The primary source of respirable dust identified is the cutting action of the shearer; however, the pct contribution of dust from coal transport through the stageloader/crusher was significant. This was primarily due to the high rate of mining, requiring rapid and constant coal transport. Techniques implemented for the control of shearer-generated dust included high drum water flow rates, deep cutting, shearer-clearer-type external water spray systems, and radio-remote control. The high water flow rates, and an enclosed stageloader with scrubber, were used to control dust during coal transport. No novel or effective control technology exists to control dust during support advance. Administrative controls for dust avoidance, and manual and batch-activated electro-hydraulic control systems were used to keep support movers out of the dust generated during support advance.

Jan 1, 1990

By Paul Saxton

INTRODUCTION AND SUMMARY This short paper deals with the history of the Nickel Plate Mine from 1898 to 1987, with the major focus on the time period 1984 to 1987. Operations from 1898 to 1955 are reviewed in a cursory manner with the emphasis on some interesting points in the early 20th century. A review of the major exploration work carried out in 1984 to 1987 is presented and the process of moving the project through feasibility, government permitting and construction is described. The Hedley gold camp is situated approximately 40 kilometres east-southeast of Princeton, in southern British Columbia. The area has had a long history of gold mining and between 1902 and 1955 approximately 1.5 million ounces of gold were won from several mineralized skarn orebodies. Most production came from the Nickel Plate and Hedley Mascot mines. AN EARLY TO MID 20TH CENTURY SUMMARY The Nickel Plate is one of the oldest mines in the province. The mine had operated from 1904 to 1930 and, after a period of shutdown, from 1934 to 1955. The mine was revived in 1967 for exploration and. will resume production during the first half of 1987. In the first period the Yale Mining Company and Daly Reduction Company operated for six years and Hedley Gold Mining Company for twenty-one. In the second period the mine was operated by the Kelowna Exploration Company Limited and Kelowna Mines Hedley Limited for twenty-one years. In the present period the mine has been revived by Mascot Gold Mines Limited.

Jan 1, 1987

By Alex G. Sciulli

According to recent estimates, nearly 30 percent of the material from underground coal mining in the United States is rejected on the surface as waste. This accumulation of almost three billion tons of coarse and fine coal refuse is primarily from coal cleaning operations. The marketable coal is intermixed with sandstone, clays, shales, and carbonaceous rocks, which must be removed and disposed of in an acceptable manner. The disposal of mineral wastes is a major environmental concern. The most common types of environmental problems associated with coal refuse disposal are acid formation, erosion, and sediment control. Other areas of concern include air and water quality, combustion control, mine sealing, and reclamation. This paper focuses on these topics and attempts to outline special environmental features which can be incorporated into the design and construction of a coal refuse facility. Often these measures can minimize and possibly eliminate the potential environ- mental hazards. It is imperative, however, that these measures be adopted prior to and during construction, because of the relative ease and cost savings compared to post-construction implementation.

Jan 1, 1983

By G. Simmons

Santa Fe Pacific Gold Corporation (SFPGC) conducted pressure oxidation pilot plant studies at Hazen Research, Inc. on the Twin Creeks refractory carbonaceous gold ores during 1993 and 1994. Previous laboratory investigations demonstrated very good gold recoveries of 90 to 95%, using CIL cyanidation after batch pressure oxidation. However, results from the pilot plant showed that several ore types responded very poorly, with gold extractions of only 45 to 75%. Since these poor recoveries were unexpected, pilot plant testing was suspended for approximately four months while extensive research activities were conducted to determine the cause(s) and identify potential solutions. This paper describes the batch and pilot plant test results, the research activities that eventually identified the cause of the gold recovery problem, and the final semicontinuous and continuous pilot plant operations that confirmed possible solutions.

Jan 1, 1997

By L. Michael Kaas

In recent years a number of data processing and analytical techniques have proven to be useful to engineers and geologists in various segments of the mineral industries. Petroleum companies were among the first to utilize the computer to store well data files and to analyze that data for exploration purposes. A few years later, metal mining companies began to apply the same basic computer methods to problems in mineral exploration, ore reserve evaluation, and open pit mine planning. Because of the increasing complexity of planning for coal mines and land reclamation, a case study was undertaken to evaluate the usefulness of computer techniques to assist mining engineers and geologists in mapping coal deposits, evaluating coal reserves, strip mine planning and land management. The data used in the study was provided by the Illinois State Geologic Survey. This paper describes some of the results of that study. First, considerations for the development of a computer data base for coal deposits are presented. Next, a series of analytical techniques for processing the data is described. Finally, the case study is presented to illustrate how the coal data base and the analytical techniques could be used in actual practice.

Jan 1, 1973

By R. A. Deju

The Basalt Waste Isolation Project of the U.S. Department of Energy is a part of the National Was re Terminal Storage Program. Its mission is to assess the feasibility of siting a nuclear waste repository in the basalt formations which underlie the Hanford Site of the U.S. Department of Energy. The progress in all program areas is summarized in this paper. Activities conducted to date have led to the identification of possible repository candidate sites within the Hanford Site.

Jan 1, 1981

By Donald L. Gaughenbaugh

Under the terms of the 1970 amendments to the Clean Air Act, the EPA established national ambient air quality standards for a number of pollutants. Sulfur dioxide (SO2) was one of these pollutants. These ambient air quality standards have had perhaps their biggest impact on the power utilities. In an effort to meet the air quality standards set forth by the EPA, utilities using high sulfur fuels have been forced to install flue gas desulfurization (FGD) systems. The majority of FGD systems in operation today are nonregenerable systems, that is the by-product of the system is disposed of, usually into settling ponds. Limestone slurry is the most common reagent used to remove SO from the flue gases. The calcium carbonate (limestone) slurry interacts with the flue gas, absorbing the SO2 and forming a by-product of calcium sulfate/sulfite which is disposed of.

Jan 1, 1986

By Robert J. Pruett

The Georgia kaolin District is the world's largest producer of kaolin. Georgia production tripled from 2,344 million metric tons in 1964 to 7,570 million metric tons in 1994. Development of the Georgia kaolin industry can be traced to the mineral resource, the adoption of innovative process technologies, and the market growth for kaolin. Georgia kaolin is an abundant and high-quality resource that shows a range of advantageous properties. Technical developments in wet processing, delamination, and calcination allowed production of high-value products. The application of kaolin pigments to the paper industry provided a market that could absorb rapid growth.

Jan 1, 1998

By William A. Vogely, DeVerle P. Harris

INTRODUCTION Perspective The phrase "minerala resource appraisal" is widely and loosely used to refer to any quantitative description of a naturally occurring source of fuels, metals, or nonmetals. This leads to confusion when mineral resources are so conceived, for the term refers generically to information on stocks-mineral endowment, resources, reserves, and potential supply-that differ in ways that are important in economic analysis. Mineral resource and other stock measures- these are not flows, e.g., the supply of minerals-have precise technical meanings, which are presented in this paper. Quotation marks are used to separate the nontechnical use of mineral resource from the technical. The term appraisal also leads to some con- fusion because it too is loosely used. When an appraisal employs probability and statistical methods, the appropriate term is estimationb, not appraisal or assessment. This paper presents a conceptual framework or mineral resource information which renders technical, or well defined, relationships of mineral endowment to physical attributes of the earth's crust and earth processes, as distinct from economic values, and identifies estimation approaches that lead to different economic measures of stocks and flows. An important result of this approach is the distinction between the relevance of mineral resource information to economic and policy issues about potential sup- ply (stocks) and dynamic supply (flows across time). With regard to policy analysis, this paper recognizes that mineral resource information has a cost as well as an imputed value. Such a treatment implies that there is an optimum state of resource ignorance, or enlightenment, for a given policy issue and that the relevant economic issue is the selection of that information strategy and appraisal methodology that is indicated by the optimum state. Until the initiation of the OPEC oil embargo, the demand for information on mineral re- sources and potential supply was limited to occasional studies commissioned by Congress or the President of the United States. In these, mineral and energy resources remained loosely de- scribed. When quantitative estimates were supplied, they were not rigorously made, and the estimates and the methodology accordingly escaped close scrutiny. Usually, neither the geo- logical nor economic bases for estimation were carefully described or critically examined. The imposition by OPEC nations of the embargo on oil caused a sudden change in the public and scientific demands for specific 'resource" appraisals, especially of oil and of uranium. These

Jan 1, 1985

By K Timtner

As shown in former publications there are problems in load sharing of backstops in multiple drives of conveyors. Therefore, detailed calculation methods and design recommendations are required. In this paper various designs of load sharing methods are described and a dynamic torque calculation method will be presented. With this method the loadsharing properties for low and high speed backstops are calculated and compared. These properties depend on the spring characteristic of the drive train between backstop and load. Furthermore, the properties depend on the method of torquearm support and shock absorber configuration. Remarkable differences for external and internal backstops are shown

Jan 1, 1998

By Peter Riba

Up until ten years ago the industry had arrived at a relatively conventional, and consistent design of coke ovens. Through the years the designers and builders were not being heavily taxed to come up with revolutionary new designs. However, the stimulus for design change was ever present. These stimuli for change are quite important and they are the driving force which produce improvements. The most obvious stimulus to change a design is commercial. To "build a better mouse trap and the world will beat a path to your door" is the well used cliche which best befits this philosophy. As in all businesses, coke oven designs require that all of the considerations, which affect the cost or the desirability of the design, be optimized. One way to increase the desirability of the particular design, 1s to make the design in- expensive to operate. Or, put another way, to increase production for the same operating cost

Jan 1, 1980

Small-scale flotation tests have been conducted to examine the effect of froth stability on the column flotation of finely pulverized coal. The results of this study demonstrate that the upgrading of coal in a column flotation cell can be significantly improved when froth stability is properly controlled through the manipulation of appropriate operating variables. Several important correlations have been established from the test data. These relationships should prove useful for the design and ore ration of column flotation cells for fine coal processing.

Jan 1, 1991

By S. K. Kawatra

Under normal conditions, a significant amount of pyrite is recovered in the froth during flotation of high-sulfur coal. In order to reduce this pyrite recovery, it is first necessary to determine the primary recovery mechanism, as different measures are required for reducing entrainment, locked-particle flotation, or true hydrophobic flotation. In this paper, evidence is presented which suggests that hydrophobic flotation is not the major mechanism for recovery of liberated pyrite, and that the bulk of the recovered pyrite is there either as a result of simple entrainment or by being physically locked with floatable coal particles.

Jan 1, 1991

By X. Meng

A kinetic model for batch leaching of various metals with different lixiviants has been developed. Overall material balances for reactants and products at the solid/liquid interface were formulated with various types of heterogeneous reactions in place at the interface. The solutions to these mass balances have been identified analytically as well as numerically using a Runge-Kutta method. Applications of these numerical solutions to various leaching systems using the rotating disc or powders have been discussed. Examples of the metal dissolution systems considered in this study include cobalt, nickel, copper and gold in acid, cyanide or ammoniacal solutions.

Jan 1, 1994

By Hemendra N. Kalia

The target to double the coal production by 1995 presents a formidable challenge to the coal mining industry. The mines of future, probably will be located in relatively difficult geological environment because of the exhaustion of the well defined bedded and easily minable deposits. To compound the problems of mining industry will be the reliance of power plants need for coal. The coal must reach the power plants on schedule to avoid expensive blackouts and brown¬outs. It will be imperative that the mines operate without interruptions and at designed capacities. The parameters which have been traditionally responsible for the interrup¬tions of production are: breakdown of production machinery, labor management relations and geological anomalies. Of these three problems, solutions for the first two can be arrived at by developing procedures to correct the situation. A planned maintenance and preventive maintenance program will go a long way in minimizing the equipment breakdowns. Labor relations will eventually improve as the miners begin to enjoy long-term employment. However, with the geological problems, the situation will probably continue to deteriorate and would require careful planning to minimize the impact of geological problems on production and safety. Some of the geological aspects which interfere with production are: faults, washouts, slips and slickensides, water bearing overlying strata, impuri¬ties in the coal seam, and presence of expansive clays in the coal floor. The design of large capacity mines will have to incorporate the geological distur¬bances and mine through them it may become very uneconomical to abandon producing sections because of the presence of the geological anomalies. This paper discus¬ses the geological aspects of coal mining which should receive consideration from the inception of the mining ventures. Pertinent geological aspects are discussed to develop the data base which will aid in evolving safe and efficient mine layouts.

Jan 1, 1976

By K. Papke

Nine western states contain significant barite deposits, but most deposits are in Nevada, which has been the principal western producer for more than three decades. Nevada produces about 85% of the total United States production, but about one-half of the barite consumed in the country is imported. Approximately 95% of the barite is used in drilling muds. Sharply decreased oil and gas drilling, starting in early 1982, severely depressed the domestic barite industry. Other problems for western barite include long distances to the areas of major drilling, high railroad-freight rates, and increased barite imports. Bedded deposits, formed by submarine exhalative processes, account for almost all western production, and reserves are large.

Jan 1, 1983

By Atmesh K. Sinha

Death and injury rates in mining have been the highest of any industry; the injury severity rates in mines have also been the highest. Tentative figures reveal that 1971 was the best year yet for the bituminous coal indus¬try with the lowest number of fatal accidents. Nevertheless, 177 men were killed at a frequency rate of 0.76 per million man hours. Coal mine accident statistics have been described at various times as unacceptable and intolerable and recently resulted in the enactment of massive legislation. The 1969 Coal Mine Health and Safety Act was passed by Congress "to improve the working conditions and practices in coal mines and to prevent accidents and occupational diseases originating in the coal mining industry." The prevention of accidents in coal mines is the statutory responsibility of mining engineers and the moral responsibility of all who have any part to play in mining coal. The questions to be answered by these men may well be - What are the reasons for the high accident rate? Are the mines as safe as they can be? Are our mines sufficiently manned to insure proper supervision of production cycles and safety requirements? Are our plans for safety committees, safety campaigns, and safety inspections sufficient? Are they producing the results intended? If not, how can these be reorganized to have a greater impact? What is the real cost of an accident? What are the immediate and long-term plans for further improvements? These questions are in no way exhaustive, and the answers are not easy. There are many aspects of mine safety, and any one of them can be the subject of a lengthy discussion. The aim of this paper, therefore, is to limit the analysis to documented fatal electrical accidents in mines so that meaningful conclusions for improvement in electrical accident-experience statistics can be made. In doing this, it is also the intention to emphasize areas of missing information and propose a few suggestions for better hazard analysis.

Jan 1, 1972