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By D G. Jefferies

This paper covers National Grid's role in the electricity market, the growth of competition in both generation and supply in that market, and the resulting impact on fuel usage, prices and the environment. It also considers other, external influencing factors on the electricity supply industry, as well as the growing trend towards globalization.

Jan 12, 1997

By J. M. Simard, S. Morissette, P. Coursol, P. Mackey

A new, powerful model is presented that focuses on plant logistics and scheduling aspects of the smelting, converting, fire refining and casting operations at the Horne smelter. This plant complex is the largest custom copper smelter in North America. It handles a wide range of feeds and utilizes a number of proprietary continuous and batch technologies that require good scheduling in order to maximize plant capacity and efficiency. The present model was developed by Xstrata Process Support, in collaboration with the Horne smelter, and uses the Arena® software to evaluate the impact of a number of plant variables on the annual copper capacity of the plant. Model development was carried out by Xstrata Process Support, in collaboration with the Horne smelter, through the effective combination of process chemistry knowledge and detailed knowledge of the plant operation (including all material flows and transfers, as well as information such as operating on-line times, plant stoppages and also scheduled and unscheduled maintenance activities). A number of case studies were then examined, including the impact of anode furnace and casting cycle times on annual copper capacity and the impact of a one-crane mode of operation in the converter aisle, which normally operates with two cranes in service. The model predictions were found to match actual plant results very well. The present modelling of plant logistics and the scheduling aspects were found to add important dimensions at the plant with regard to projections of the real-life plant capacity. As demonstrated in the present case, this type of model and application can have a significant impact on optimizing operations at a given plant. This impact is particularly important in the current market environment, where emphasis is on maximizing plant output and lowering costs. These models can help yield the easily obtained gains that are clearly desirable in these times. Xstrata Process Support has developed Arena models for other operations and is available to explore new applications for a win-win situation at other plants, including mines and concentrator operations.

Jan 1, 2009

Bioleaching Metals from Waste Printed Circuit Boards and the Shapes of Microorganisms

Sep 13, 2010

By Joe Maher

Adequate mine roof support to insure the safety of men and equipment is essential to successful mining. It is also expensive, amounting to more than one-fifth of the total mining cost at the White Pine mine. Cost effectiveness is therefore a prime consideration in developing optimum roof support. Roof bolt length is an important cost factor. This Phase II work compared uniform four-foot length Resin Bolts with the hitherto standard alternating four-foot and six-foot Resin Bolts, aiming at more cost-effective roof bolting. The data generated under this Phase II show that there is no discernible difference in the roof support given by uniform four-foot, and by alternating four- and six-foot, Resin Bolts in the relatively difficult ground selected for a severe initial test comparison; subsequent data from less difficult ground led to the same conclusion, namely no discernible difference between four-foot and four-six foot bolting.

Jan 1, 1975

The following report summarizes the results of engineering feasibility studies whose purpose was to assess the probable efficiency, reliability, safety and cost of a number of possible methods for removal of radon gas from the ambient air in underground mines. Fourteen candidate techniques were evaluated. Seven of these were based on specific individual principles, and seven were based on combinations of these principles. The individual principles were as follows: 1. Activated charcoal 2. Organic fluids 3. Semipermeable membranes 4. Molecular sieves 4. Cryogenics 6. Chemical reaction 7. Centrifuge The combinations were: 8. Cryogenics and activated charcoal 9. Cryogenics and molecular sieves 10. Cryogenics and chemical reactions 11. Membrane filters and organic fluids 12. Membrane filters, cryogenics and activated charcoal 13. Membrane filters and chemical reactions 14. Silica and an Organic Fluid

Jan 1, 1975

By S. S. Gross

A program was conducted to determine whether sufficient quantities of the flame retardant, ammonium phosphate, could be incorporated in a water-based foam solution to prevent or delay reignition (burnback) without. significant degradation of foam properties. Up to 20% of mono and diammonium phosphate was added .to d high expansion foam solution. This mixture was applied as a high expansion foam to burning wood and coal samples. The effect of this mixture on burnback was laboratory tested by placing the wood or coal sample in front of a radiant panel. It was found that diammonium phosphate levels of 20% by weight prevented reignition without degrading foam properties. A field test was then conducted using a 20%, diammonium phosphate mixture and a control with no phosphate on a wood crib fire. The experimental foam did extinguish the crib fire faster than the control as evidenced by the smoke from the crib. However neither crib reignited.

Jan 1, 1982

By Victor De Ysassi

THE iron mines of Spain are located on the mountain ridge forming the boundary between the, Teruel and Guadalajara provinces, called Sierra Menera. They form a property of 25 mines extending over an area of 1,677 hectares (4,140 acres) situated at a height varying from 1,200 m. (3,940 ft.) to 1,500 m. (4,920 ft.) above sea level. The deposit follows the direction north to south; huge masses of ore are being found both on the slopes and at the summit of the Sierra. The ore occurs among quartzites and magnesite limestone, in some places overlaid by quartzite 15 in. (50 ft.) thick; in some others (and this is more general) the ore is overlaid by earth and boulders of quartzite origin,; this layer is about 8 m. (26 ft.) thick. The ore beds occupy the geological horizon of the Superior Trias or Muschelkask, which are here in direct contact with the Silurian quartzites. The lime-stones have been more or less transformed. There is ample evidence to show that these mines were worked in very ancient times-objects and tools employed in mining by the ancient Romans and Arabs are to be found plentifully in old workings which extend down into the deposits. It has been estimated that more than 10,000,000 tons of ore were mined in the old days in this district and carried to the primitive forges in the vicinity where iron of much renown in Spain was extracted. Remains of more than 20 of these forges are found in the neighborhood of Sierra Menera and are usually situated near waterfalls and forests. Much investigation has been carried on for the purpose of determining the quantity of ore to be found in these mines, but no exact calculations can be made at present. When the investigation is completed it will surely be found that the deposit contains a much larger quantity than the 100,000,000 tons indicated by the present workings.

Jan 2, 1916

By Sidney Speil

In the study of clays and related minerals, the analytical techniques commonly employed in mineral analysis are not always applicable. The X-ray examination of a clay sample usually will show the major constituents, but often minor· clay impurities will not be detected because of line broadening and the similarity of the main lines of clay· mineral diffraction patterns, The petrographic analysis of clay minerals with clay particles as small as a few microns is usually difficult. With still smaller particles, a gross effect often is noted in which a mixture of several constituents gives the appearance of a single constituent with the mean optical-characteristics of the mixture. 3/ The electron microscope has recently been used to study clay particle shapes of various aluminosilicates. 4/ However, this method has not yet been sufficiently explored. The Chemical method in which a mineralogical analysis is calculated from the oxide chemical analysis has been discussed by Wilson 5/ and others, and many of the shortcomings have been pointed out. It should also be recognized that the variable alkali and alkaline earth content of bentonites makes it inaccurate to assign these basic elements arbitrarily to feldspar or mica in any clay that contains appreciable bentonite.

Jul 1, 1944

By Alfred Wild

The Kraftile Co. plant, Fremont, Alameda County, Calif.--the largest producer of glazed, structural wall units west of the Rocky Mountains--maintains modern processing facilities to evaluate and blend a wide variety of clays from several sources to produce quality products. The report desribes the prospecting, exploration, and test methods used to locate raw material sources and covers processing methods, cost factors, and trends. Also, the geologic and ceramic factors are considered in a general discussion of the economics, potentials, and requirements of clays as raw materials for ceramic tile manufacturing.

Jan 1, 1963

By Witold J. S. Ostrowski

The shaft structure being part of an underground mine, depends on programned functional duties, and on geological and hydrological conditions. The majority of Canadian metal mine shafts are in hard competent igneous rocks, which are in an elastic state of equilibrium around the excavation. Others penetrate soft sedimentary or very weak water-bearing rock formations in which the equilibrium varies from plastic to hydrostatic. Knowledge of how to interpret the underground conditions, determine acting forces and design proper structures is essential for the production and safety of the future mine.

Jan 1, 1973

By Robert L. Lagace

A whole-mine experiment to assess the practical feasibility and utility of the dedicated-wire technique for overcoming poor trolley carrier phone system performance at a large underground coal mine was designed, performed, and evaluated. The technique involves the use of a single, low-loss, properly terminated and branched auxiliary wire placed in the rail haulageway. This auxiliary dedicated wire allows signals to electromagnetically couple to the trolley wire/rail transmission line, and thereby significantly decrease the overall signal attenuation rate on the trolley wire/rail line. The in-mine dedicated-wire demonstration program and its results, conclusions, and recommendations are described. The dedicated-wire technique is shown to be a valid and practical one for significantly improving carrier phone system performance in coal mines.

Jan 1, 1981

By P. H. Morris

Nineteen field trials of the co-disposal of fine coal tailings and coarse coal wastes were conducted at the dual Goonyella-Riverside mine in Queensland and at the Hunter Valley No. 1 and Warkworth mines in New South Wales, Australia. The profiles of and the sorting that occurred on the co-disposal deltas are described and an existing theory of subaerial deposition, originally developed for mine tailings alone, is shown to apply to the co-disposed wastes. This enables the dimensionless profiles of large deltas, which may take years to deposit, to be predicted from data obtained from a small delta formed in a few days or even hours

Jun 19, 1905

By P. G. Pigott

The lack of technical information regarding the physical characteristics of kaolins and bauxitic kaolins, rejected during the mining of bauxite near Eufaula, Ala., has retarded their commercial utilization. This investigation was undertaken to determine their behavior when used in refractories. Ores were evaluated as refractory raw materials by compounding dry-press mixtures and specialties following procedures common to the industry. Products now on the market were used for comparison in laboratory evaluation.

Jan 1, 1959

By H. G. Hammon

Uranium miners have been shown to develop lung cancer in direct proportion to the time of exposure in the mine and the concentration of radioactivity (cumulative working level).1 Radon gas is continually evolved from the uranium ore, but because of its shoe half-life, 3.82 days, it is soon decomposed into particulate daughter products, which along with the dust in the mine, become deposited in the miners' lungs. At present, massive ventilation is the only effective method of reducing the radioactivity concentration in the mines. However, the Bureau of Mines is evaluating the possibility of using coatings on the mine wall that will have sufficiently low permeability to radon that the gas will decompose into the particulate daughter products before it can permeate the coating. Permanently trapped in the coating, the daughter products would be prevented from dispersing in the mine atmosphere. Lawrence Livermore Laboratory was asked to aid in this investigation. The direct determination of radon permeability is more difficult than that of the other noble gases because of the short half-life of the gas and radioactive contamination of the apparatus. We felt that it should be possible to estimate radon permeation coefficients from other noble gas permeation coefficients. It was noted that the log of the diffusion constants for helium, neon, argon, and krypton, as reported by Meares2,3 plotted to a straight line-against the square of-the gas molecularddia meter. The log of the permeation coefficients also plotted to a straight line against the square of the gas molecular diameter. Thus, by determining the permeation coefficients of such gases as argon and krypton through various films and coatings, it appeared likely that radon permeation coefficients could be estimated. In addition we felt it should be possible to find some relationship between polymer structure and he noble gas permeation coefficient that would aid in the selection of coatings materials as radon barriers.

Jan 1, 1975

By T. Bertke

This document assesses the environmental aspects of a preliminary design for processing kaolin clay as the domestic resource for recovery of alumina by a hydrochloric acid leach-HCl gas induced crystallization process. The report covers waste sources, control measures, and potential environmental and health effects applicable to the process technology.

Jan 1, 1980

By John L. Miller

The synthetic fluormicas may be divided on the basis of silicon content into tetrasilicic, trisilicic, and disilicic. Properties of lead and barium disilicic fluormicas were determined to characterize these two representative members of the disilicic group. Properties described include unit-cell parameters from X-ray diffraction, optical data, chemical composition, density, melting point, and mechanical and dielectric properties. Both the lead and the barium micas were typically monoclinic; neither was sufficiently cleavable to yield usable mica splittings. Both yielded polycrystalline, machinable ceramics with excellent mechanical and dielectric properties.

Jan 1, 1963

By J. C. Franklin

A data-acquisition system was designed by the Bureau of Mines to monitor five detectors with radon continuously flowing through each. These detectors could be monitored up to 12 times an hour, but were only monitored according to a preset time, thus allowing radon to be monitored continuously in a uranium mine. The counter can be set to monitor each detector for any period of time up to 16.5 minutes. This allows very low concentrations to be monitored longer to reduce statistical error. There would be no upper limit in radon concentration that could be monitored, but there would be a lower limit of 50 picocuries per liter (pCi/l). Each detector was cylibrated in the laboratory by the Lucas flask method. Multiple samples were taken at two different concentrations, and the correction factor for each detector was determined by a least squares fit of the data. To verify the calibrations, a series of measurements at several concentrations were made against a constant source. Our agreement at low radon concentrations (300 pCi/i) with the two-filter method as within 3 percent; thus, the total error would be this difference plus the two-filter error. At high concentrations the coefficient of variation ranged between 2.1 and 9.8 percent for the five different detector units.

Jan 1, 1976

By K. Sasaki, W. Astuti, N. Okibe, T. Hirajima

"The kinetics of leaching of a saprolitic ore from Indonesia by citric acid solution under atmospheric pressure was investigated. An examination of the effects of leaching temperature, citric acid concentration, pulp density and ore particle size on the dissolution rate of nickel found that they all had significant influence on the rate. The highest nickel recovery (95.6 percent) was achieved under the leaching conditions of ore particle size of 212-355 microns, citric acid concentration of 1 M, leaching time of 15 days, pulp density of 20 weight/volume percent, leaching temperature of 40°C and shaker speed of 200 rpm. The shrinking core model was found to be appropriate for describing the leaching kinetics of this ore in citric acid solutions at atmospheric pressure. The experimental data were well interpreted by this model with rate of reaction controlled by diffusion through the solid product layer. Using the Arrhenius expression, the apparent activation energy for nickel dissolution was evaluated as 12.38 kJ/mol. Finally, on the basis of the shrinking core model, a proposed empirical kinetic model for the leaching of nickel from this Indonesian saprolitic ore was expressed as a mathematical model, which was verified as consistent with the observed experimental results.IntroductionIndonesia has some of the world’s largest nickel laterite reserves and was the largest producer of nickel – in the form of nickel lateritic ores – in the world in 2013 (Merchant Research and Consulting Ltd, 2014). However, only high-grade saprolites are processed in Indonesia using pyrometallurgical methods to produce ferronickel and nickel matte. Lower-grade saprolites and limonites are removed, becoming waste or overburden in mining site areas. Hydrometallurgical methods, involving either chemical leaching or bioleaching, are now seen as the most important technologies for treating nickel laterites in the future because of their advantage of not only extracting nickel and iron but also other valuable elements. In addition, hydrometallurgical methods consume less energy and have lower capital and operational costs. Although they are recognized to be more suited to limonites, some researchers have studied their use in the extraction of nickel and other metals from saprolites (Guo et al., 2009; Lu et al., 2013). Hydrometallurgical processes for the extraction of metals, especially nickel, promise to be meaningful alternatives to pyrometallurgical processes to primarily treat low-grade saprolites for which pyrometallurgical processing is not favorable"

Jan 1, 2015

By Terry J. Close

In 1986 and 1987, at the request of the U.S. Bureau of Land Management, U.S. Bureau of Mines personnel studied 7,040 acres of the 7,240-acre Sheep Mountain Wilderness Study Area (OR-006-003) in order to evaluate its identified mineral resources. The area studied is along the divide between the Snake River and Pine Creek about 1.5 mi south of the village of Oxbow in Baker County, OR. No mineral resources or mineral-related activities were identified in the Sheep Mountain study area. The basalt covering most of the study area has no known mineralized sites. However, it contains common agate and opal that is of limited interest to mineral collectors. This basalt (stone) could be used locally as construction material (crushed stone or fill); however, suitable material is wide spread in the region and more accessible to possible markets.

Jan 1, 1987

By David R. Peterson

This user's manual covers a set of 5 computer codes which were generated during development of a simulation of deep ocean mining operational economics. Table 1.1 provides a summary of these codes, and a more thorough description of each follows, In addition to the descriptions in this user's manual, internal documentation is provided throughout each code, except for the very simple ones, for ease of understanding or possible modification. The two major codes are MINER, which performs the deep ocean mining system operational simulation, and MSWEEP, which calculates the sweep and feed efficiencies for a set of collector paths generated by MINER. The standard operating procedure is to input the system and operating parameters to MINER, which computes a set of collector paths automatically and stores the information in the fife PATH.DAT. MSWEEP subsequently retrieves the collector path data in PATH.DAT, and uses it to calculate sweep and feed efficiency. Separating MINER and MSWEEP allows parmetric execution of MSWEEP without recomputing the collector paths with MINER. PIPEST, RESP, and OBSTCL are special-purpose codes described in more detail in the following documentation.

Jan 1, 1979