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By R. L. Thoms

Compressed air energy storage (CAES) has been initiated recently in West Germany with a 290 MW peaking-power facility utilizing twin cavities with volumes of 150,000 m3 each in the Huntorf salt dome (1). The implementation of CAES in several geologic media is being studied carefully in the United States (2); however, the use of cavities for CAES in salt domes or salt anticlines and the associated long-term stability of these cavities is the specific topic of this paper (3). The cavities represent an essential element in a CAES plant, and thus should be designed and operated to perform with "stability" over the planned life of the overall facility. As employed herein, cavity stability implies the extent to which an acceptable amount of cavity storage volume can be utilized with economic maintenance over the planned life of the overall facility. In this sense stability is relative to the planned use of a storage cavity. Figure 1. depicts the salt deposits of the United States (U.S.) (4). The Gulf Coast region includes the only confirmed salt dome basin in the U.S., although salt structures also exist as anticlines in the Paradox Basin of Utah and Colorado. Because of the relatively small amount of elevation change within the Gulf Coast, CAES in salt dome cavities appears to hold considerably more potential for energy storage in this region than more traditional "pumped hydro" systems.

Jan 1, 1979

By Peter Kreisman

This paper and four other papers on the MEQB Regional Copper-Nickel Study, presented today at the 1980 SME-AIME Fall Meeting are based on four years of extensive inter-disciplinary research and impact analysis supported largely by the Legislative Commission on Minnesota Resources. This study produced over 180 technical reports, the results of which are summarized in an Executive Summary available from the Minnesota State Planning Agency, St. Paul, Minnesota. Those wishing to examine the many scientific, engineering, environmental, social or economic issues addressed by the study are encouraged to obtain a copy of the executive summary. The executive summary includes a bibliography of all technical reports produced by the Regional Copper-Nickel Study and describes the five-volume, 26 chapter Regional Copper-Nickel Study Report.

Jan 1, 1980

By E. A. Schmidt

The Thompson Creek molybdenum deposit is located in the Bayhorse mining district about 20 air miles southwest from Challis, Idaho. Cyprus Mines Corporation began exploration on the property in 1968, and at present is in the pre-production stripping phase. Molybdenum mineralization is contained in a late Cretaceous (88 m.y.), composite, biotite granodiorite-quartz monzonite intrusive complex. The complex intruded carbonaceous argillites, causing local silicification and hornfelsing of the sedimentary rocks. The main portion of the orebody is unconformably overlain by up to 1000 ft of Challis volcanic rocks (49 m.y.). Surface mineralization and related rock alteration can be recognized over a 2500- x 8000-ft area extending northwesterly from the discovery outcrop. Molybdenite occurs in a network of subparallel quartz-biotite-muscovite-orthoclase veins and veinlets within the intrusive rocks. The zone of +0.020/0 Mo mineralization outlines a steeply dipping tabular configuration in the main orebody and gradually changes into a hood-shaped configuration along strike to the northwest. The overall grade [ ] of the deposit is controlled by the abundance of the quartz- molybdenite veins and veinlets in the intrusive rock. Very little disseminated mineralization is present, and no economic mineralization occurs in the argillaceous sedimentary rocks. Muscovite, biotite, and orthoclase/microcline define three alteration zones that conform with the overall zone of mineralization. The upper alteration zone contains dominantly muscovite and sericite associated with quartz veins. The central zone contains coarse biotite and locally orthoclase and microcline. Molybdenite is most abundant within this zone. The lower zone contains thin envelopes of orthoclase/microcline around quartz veins. Based on about 313,000 ft of drilling and 8592 ft of underground development work, computer-derived ore reserve calculations indicate 200 million tons averaging 0.1 1% Mo at a 0.050/0 Mo cutoff grade with a waste to ore stripping ratio of about 3:l.

Jan 1, 2013

By Y. Luo

Surface subsidence process due to underground coal mining often has the potential to cause problems to buried pipelines. In this paper, a technique for assessing the stress level on a subsidence-affected pipeline is introduced. The main contributors for the stresses on the pipelines are identified. Mitigation techniques for reducing the stress on the pipeline have been proposed and successfully tested.

Jan 1, 1997

By Eugene C. Spilker

Cross country belt conveyors are becoming the preferred method of bulk material handling in the industrial complex. Installed cost, maintenance, reliability, simplicity and operating expense enhance this choice, especially when faced with rising cost and questionable availability of liquid fuels. Conveyor flights are getting longer, faster, and higher in capacity, and are being installed in rugged terrain. Rights of way are often difficult to obtain. All these considerations lead up to design aspects well beyond those for in-plant conveyors. This paper points out some of the aspects that lead to the successful design of a cross country belt conveyor system.

Jan 1, 1980

By S. M. Hossaini, M. Ataei, H. Moosavi

The abstract highlights the importance of pillar stability in underground coal mines and the influence of rock mass strength and joint orientation on pillar behavior. The study employs numerical modeling using the distinct element code (UDEC) to investigate the impact of these factors on pillar stability. The research considers different joint orientations and varying rock mass strengths, analyzing parameters like stress distribution, displacement, and failure patterns. The findings reveal that both joint orientation and rock mass strength significantly affect pillar stability, with specific combinations leading to reduced safety factors and increased deformation. The study concludes by emphasizing the importance of considering these factors in pillar design for safe and efficient mining operations.

Apr 4, 2022

By C. D. Buttgereit

A variety of mathematical techniques are available in the pertinent literature concerning the interpretation and reduction of aeromagnetic data. The quantitative methods applicable to this data en¬compass a wide spectrum including filtering, continuation, derivatives, reduction to the poles, spectral analysis, and "undraping" of flight line data. With the aid of the digital computer, the techniques listed, and others, can be computationally performed on a gridded data set. In addition, current sophisticated computer hardware permits the systems analyst greater latitude in the storage and retrieval of data and in the display of resultant naps on a digital x-y plotter than previously available. Although many interpretive techniques concerning magnetic data have been published and computer machinery has been on the market, little has been written incorporating both disciplines into a unified digital processing system. In the present paper, a general purpose system in given which in designed for routine use in the interpretation of aeromagnetic (and other potential field, etc.) maps.

Jan 1, 1970

By P. Clifford

FIPR-sponsored research will playa critical role in enhancing the competitiveness of the Florida phosphate industry as ore grade declines and environmental restrictions tighten. FIPR's program seeks to improve surface mining and pipeline transportation while reducing the energy cost for pumping phosphate matrix. The development of a reliable on-line analyzer and a modern process control strategy will result in improved processing efficiency. Significant improvement in overall efficiency will also be realized as the industry adopts column flotation technology. Economic acidulation of high-Insol rock will allow the industry to adopt simplified flotation flowsheets thereby reducing operating costs. Various applications of phosphogypsum would save the industry millions of dollars in constructing and closing gypsum stacks.

Jan 1, 1998

By MARK J. VANARELLI

Estimating groundwater inflows in rock deep tunnels is critical to the safety of personnel constructing the tunnel and the cost of construction. This paper presents two case studies for estimating steady-state groundwater inflows into deep rock tunnels. The case studies included the Chattahoochee and Nancy Creek tunnels. In this paper, statistical methods were applied to packer test data obtained from exploratory borings during geotechnical site investigations. A semi-empirical procedure was utilized for estimating groundwater inflows into these deep rock tunnels. It is the most widely used method/procedure in the tunnel industry. The Chattahoochee and Nancy Creek tunnels are deep rock tunnels which exhibit radial flow conditions. For the radial flow condition, a statistical analysis presented in this paper indicates that the semi-empirical procedure works well; however, variations in the procedure and/or an insufficient amount of testing could lead to underestimations of the inflow quantities. Packer test data plotted in histograms were observed in all cases to be log-normally distributed for the radial flow condition. Modeling using Monte Carlo simulations was observed to be an effective tool for removing irregularities in the distribution of the data and incorporating high-end permeability data to derive reasonable groundwater inflow estimates. This paper is based on the PhD thesis entitled “Improvements to the Current State of the Practice in Steady-State, Groundwater Inflow Estimates into Rock Tunnels based on the Application of Statistical Analysis Methods of Packer Test Data obtained from Exploratory Borings During Geotechnical Site Investigations.”

Oct 9, 2020

By W. K. Connor, O&apos

The Bureau of Mines is investigating the Co and Mn resource of the West-Central Arkansas District, including field investigations, mineralogical characterization, beneficiation, and hydrometallurgical tests. The deposits occur within the Ouachita Mountains and are con-trolled structurally, occurring along the axes of anticlines making up the mountain ridges. Brecciated novaculite is cemented with a mixture of Mn oxides, primarily cryptomelane and psilome-lane. Cobalt is concentrated within a particular Mn oxide phase, lithiophorite. Chemical analyses on head samples reported up to 25 pct Mn and 0.17 pct Co. Magnetic separation yielded products with up to 41 pct Mn and 0.22 pct Co at recoveries of 95 pct Mn and 93 pct Co.

Jan 1, 1991

By Ashraf A. M. A. Wali

Many of the economic resources of Egypt have been recognized and exploited for thousands of years (e.g. gold and copper). Most of these minerals, particularly those from hard-rock sited deposits, are found in complex form along with other components while those present in sedimentary sequences are largely in simple compounds or as native elements. Recognition of their characteristic settings (structure, basin development, environment of formation etc.) is the main clue in predicting and locating their presence. The main economic minerals exploited in Egypt today come from sedimentary sequences and include sodium and potassium chlorides, gypsum, sulfur, and sedimentary iron ores. Large amounts of low grade sedimentary phosphates are known but are not of economic value at today's prices. Recent intensive investigation in the north-eastern Sinai (EI Arish) and along the southern coasts of the Gulf of Suez has revealed new and extensive sulfur and chloride deposits, and considerable oil and gas are now being exploited from closely related sediments. Tin is the only mineral that is produced from hard-rock sources, and gold and copper deposits are present but not of high enough grade to be economically viable. However, a significant part of Egypt has not yet been studied in enough detail to close the door on future discoveries. Another point of considerable geological interest is the presence of diverse, modern evaporitic settings, from which we may draw the analogs for many of the older gypsum, anhydrite, chloride and sulfur de-posits. In fact these analogs are so well displayed that both the Sinai and Gulf of Suez-Red Sea evaporites (Middle and Upper Miocene) can be readily compared with these modern deposits.

Jan 1, 1990

By Muhammad Hashim Rasa, Ali Aras

Recovering valuable metals from tailings not only provides a source of income but also helps conserve natural resources, thus reducing the environmental impact of mining activities. This study aimed to recover cobalt using tailings of the Küre flotation plant, which were determined to contain 0.17% Co. Flotation tests were conducted on samples taken from the tailings to investigate the effects of pH and pH conditioning time, as well as types and amounts of depressant, collector, and frother on the grade and recovery of Co in rougher flotation tests. Optimal flotation conditions were determined to be pH 6, a pH conditioning time of 7 min, and dosages of 50 g/t, 100 g/t, and 20 g/t of sodium hexametaphosphate, X-231, and DF250, respectively. According to the rougher flotation test results, a concentrate with a Co grade of 0.46% and a Co recovery of 84.15% was obtained. In the concentrate obtained using cleaner flotation tests, the Co grade increased to 0.49% and Co recovery increased to 90.56%. These results show that froth flotation, carried out with the appropriate reagents, is a successful method for recovering Co by enriching the flotation plant tailings.

May 17, 2023

By H. Y. Yang, L. L. Tong

Semicontinuous-flow, multistage biooxidation experiments of a Chinese refractory, high-sulfur gold concentrate were conducted with different pulp densities for gold recovery. The maximum iron, sulfur and arsenic oxidation rates of 90.0, 88.8 and 96.4 percent, respectively, were obtained in the experiments with 5 percent pulp density. The highest gold and silver recoveries of 96.1 and 68.9 percent, respectively, were achieved by cyanidation. The negative effect of high pulp density on biooxidation was related to the decrease of free and adsorbed cell concentrations with increasing pulp density. The data of iron oxidation from the semicontinuous biooxidation experiments were best fitted by a shrinking core model in which the chemical reaction controlled the rate. The dissolution kinetics of sulfur and arsenic were therefore analyzed by a shrinking core model in which the internal diffusion controlled the bioleaching rates. For the quantitative description of biooxidation efficiency, two parameters — mass dissolution rate and volume dissolution rate — were proposed. In the first stage, the mass dissolution rates of minerals were negatively correlated while the volume dissolution rates were positively correlated with the actual pulp density. The iron and sulfur mass dissolution rates decreased with increasing actual pulp densities in the third and fourth stage, while linear increasing relationships between the volume dissolution rates of minerals and the actual pulp density were observed from the second to fourth stage. The highest mass dissolution rates of minerals were obtained in the first stage with 5 percent pulp density. The highest volume dissolution rates of minerals were obtained in the first stage with 15 percent pulp density. Compared to the volume dissolution rate, the mass dissolution rate was more intuitive to reflect the negative effect of high pulp density on biooxidation efficiency.

By R. A. Winters

At the operations level, productivity is a principle key to profitability. If you are competing with other mines that are paying roughly the same wage rate and the same prices for capital, materials, and energy, the only way your profit can be greater is by producing more output per unit of input. Mines with higher productivity have higher profit margins. Higher profit margins lead to greater operating cash flow, and cash flow is what distinguishes a dog from a cash cow. The turnaround in U.S. metals during the 1980s was in large part due to incredible improvements in productivity. According to statistics compiled by Kaufmann, 1991, labor productivity, measured as tonnes of primary production/manhour, increased 64% in steel, 94% in copper, 75% in lead, 143% in zinc, 132% in molybdenum, and 75% in gold. These improvements were hard won. However, with most modernization programs now complete, measuring and monitoring productivity becomes even more important as producers strive to maintain the gains they have achieved.

Jan 1, 1993

By J. C. Stankus, S. Guo, S. S. Peng

In this paper, a model is developed for a resin anchor bolt system in which the smooth bar is modeled by using one-dimensional truss elements, and the resin annulus is modeled by using axisymmetric elements. These two submodels are combined and then incorporated into an existing computer code called Roofbolt. After this development, all of the components in the resin anchor bolt system, including smooth bar, bearing plate and resin annulus, can be correctly modeled.

Jan 1, 1997

By I. R. M. Chaston

Abstract. This paper puts forward the concept of 'radial' plant layout where all crushing, milling and treatment operations are preferably concentrated in one central area and these separate stages are connected by radiating conveyors to and from outside storage areas. This system is contrasted to the more customary system of 'linear' plant layout where the crushing, milling and often the treatment operations follow one after the other in separate buildings. The radial system simplifies and improves contral and supervision to a very considerable extent and can lead to a form of continuous plant operation with the separate sectors shutting down in succession for necessary maintenance while maintaining the overall plant operation. The paper is illustrated with example: from past and recent diamond treatment plant practice in South Africa which demonstrate the reduction in plant labour achieved by this system. Previous objection to this type of layout on the grounds that it inhibited plant expansion are shown to be unwarranted. Radial Layout for Increased Treatment Plant Productivity A great deal of time and trouble is spent by highly qualified and experience( metallurgists in developing the right treatment process for a given ore. This process is then often expressed in a treatment flowsheet of the type shown in Fig. 1 which shows a typical diamond plant. This flowsheet, when completed, is commonly handed over to the mechanical engineers who then design the layout of the equipment indicated on the flowsheet and produce the working drawings upon which the detailed construction of the treatment plant will be based. It is an unfortunate fact that the tedious and time-consuming juggling of equipment and inter-plant transportation is often left to hard-working draughtsmen who, however capable' in their field, lack practical experience in the day-to-day operation and maintenance of the treatment plants they design. As a result many plants have been produced which, while they satisfy the requirements of the flowsheet with minimum capital requirements, cost far more than should be necessary to op¬erate and maintain. It is often possible to change individual items of equipment which do not achieve the performance required of them, but it is usually extremely expensive to change the basic layout of the plant if this should be found to be unsatisfactory. It should therefore be recognised that great care and attention should be spent on consideration of the basic layout of any treatment plant and that the views of both designers and operators should be fully regarded before settling upon the inevitable compromise dictated by the varying requirements of process-engineering and economics. It is unfortunate that this important subject receives such scant regard in the standard ore dressing text books and hand-books, being usually dismissed in a few paragraphs.

Jan 1, 1977

By John B. Goddard

Crystallization of ammonium paratungstate (APT) is frequently the last effective purification step in producing high-purity tungsten. However, crystallizer mother liquors are often several times higher in tungsten than predicted by the solubility of APT. The formation of heteropoly anions, particularly those containing phosphorus and silicon, is largely responsible. Solubility of tungsten in APT mother liquor can be linearly correlated with the concentration of these and other impurities. The problem can be overcome by direct treatment of the crystallizer feed solution with alum. By appropriate treatment, the aluminum hydroxide flocculates and is easily filtered, resulting in a purified low-aluminum crystallizer feed from which high APT yields can be attained.

Jan 1, 1984

By R. J. Sweigard

Estimated costs and revenues can be used in the evaluation of post- mining land use alternatives. However, post-mining land use decisions have to be made in an environment complicated by several additional factors. These factors, including cultural, natural, and managerial issues, are not as easily quantified as costs and revenues but may be more important determinants. There- fore, some approach is needed to attach relative weight to the various factors. The concept of fuzzy sets assembled into a structured hierarchy facilitates analysis of the relative value of individual factors and their impact upon each alternative under consideration. In this paper, a method is presented which employs fuzzy set analysis to evaluate postmining land use plans on the basis of these nonquantitative factors.

Jan 1, 1986

By Borje Bjorkvall

At LKAB's plants in Lappland, Sweden, sintered pellets are manu-factured according to three different industrial processes, viz. shaft furnace at Malmberget, straight-grate at Kiruna and grate-kiln at Svappavaara. At present the total annual capacity amounts to 4.7 million tons. However, since it has been decided to erect a new straight-grate plant (2.5 million tons) at Malmberget, and because of the decision to extend and rebuild the existing plants, it is estimated that the annual capacity will be increased to somewhat over 8 million tons by 1973. The great majority of the pellets produced is exported. They are thus reloaded several times and generally speaking roughly handled, resulting in larger or smaller product losses on arrival at the point of use. It is there-fore of great economical interest to have a good control over the transport strength of the pellets by appropriate quality testing at the point of production. In addition to good transport strength, further demands are ob-viously made on pellets destined for blast furnace operation. The blast furnace burden must maintain a good permeability for the gas. The pellets must thus have a favourable size distribution and must not be so weakened by reduction that they disintegrate under the stresses and clog the blast furnace shaft. Furthermore, the burden must have good reducibility. An increase of the rate of reduction can obviously mean increased blast furnace capacity and reduced coke consumption. In order to optimise the properties of the pellets in these respects, the producer must also be thoroughly familiar with their behaviour during reduction, particularly as the customer's interest in the reduction properties of the pellets' has increased over the last few years. Up to now the only quality demands the customer has made have generally had to do with the cold strength and the screen analysis. Thus a quality control of in addition to good transport strength, further demands are obviously made on pellets destined for blast furnace operation. The blast furnace burden must maintain a good permeability for the gas. The pellets must thus have a favourable size distribution and must not be so weakened by reduction that they disintegrate under the stresses and clog the blast furnace shaft. Furthermore, the burden must have good reducibility. An increase of the rate of reduction can obviously mean increased blast furnace capacity and reduced coke consumption. In order to optimise the properties of the pellets in these respects, the producer must also be thoroughly familiar with their behaviour during reduction, particularly as the customer's interest in the reduction properties of the pellets' has increased over the last few years. Up to now the only quality demands the customer has made have generally had to do with the cold strength and the screen analysis. Thus a quality control of

Jan 1, 1972

By W. C. Bagby

The Dee disseminated gold deposit is the northernmost mine in the Carlin gold belt. We analyzed soil samples £ran undisturbed areas overlying the deposit to determine the usefulness of soil geochemistry in identifying ore zones. The depth of sampling ranged from 12 to 14 inches, depending on soil development. The -80 mesh fraction was analyzed by atomic absorption for Au, As, Sb, Hg, and T1 and by semiquantitative spectrographic analysis for Ag. Highly anomalous Au, Kg, As, Ag, and Sb are most closely associated with ore zones whereas T1 is more broadly dispersed. Hg is the only element that identifies deep ore.

Jan 1, 1984