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By F. Taylor Ostrander

Some countries are infinitely poorer than others in mineral resources-despite the perfect equality of their political leaders ambitions. Compare the mineral poverty of Kenya and Tanganyika with the riches of Katanga Province and Northern Rhodesia. Compare Paraguay with Chile, There never has been any equality in the distribution of nature's wealth. Minerals cannot play any role at all in economic development where they don't exist, and there are bound to be differential rates of economic development where there are basic differences in the wealth of mineral resources available. Africa is my principal area of interest and I know that there is an unfortunate but widespread misconception about Africa's "vast mineral resources, "its "untapped mineral wealth." Why is it untapped? Why is it undeveloped?

Jan 1, 1963

By Nobuharu Isago, Atsushi Kusaka, Kosuke Kawata

"Strong earthquakes occur frequently in Japan, and some rock tunnels have sustained severe damages on their permanent lining. Many road tunnels, which were constructed by conventional steel arch support and timber lagging method, exist in Japan and they need risk mitigation measures against earthquakes as per our empirical knowledge. Many reinforcing measures for deformed tunnels that may be effective against earthquakes are developed; however, behaviors during earthquakes are not fully understood.In this study, static loading tests and numerical analysis, which simulate a loading condition during earthquakes, were carried out to clarify the effect of the countermeasures. The Load-bearing capacity is estimated for the tunnel structures facilitated by the installment of an inverted arch; however, a joint between inverted arch and sidewall become structural weakness. Rock bolts and carbon fiber sheets have a potential able to mitigate the risks of collapse of the lining by the forces from an earthquake.INTRODUCTIONA number of rock tunnels with no apparent unfavorable ground conditions suffered severe damage, including the collapse of their permanent lining, in large seismic events such as the Chuetsu Earthquake in 2004 (e.g., Mashimo 2005). Since these tunnels were considered to exhibit the required structural strength to survive earthquakes, studies are being carried out to clarify the mechanical behavior of tunnels during earthquakes and their damage mechanism (e.g., Kusaka et al. 2009); however, the aseismic design methodology for mountain tunnels has not yet been established.In many cases of earthquake-damaged tunnels, some defects already existed, such as improper construction and deterioration of lining concrete. Although countermeasures are usually implemented against such problems, their earthquake-resistant effect was not fully understood.In this study, static loading tests and numerical analyses to reproduce these tests were carried out assuming that a rock tunnel was affected by the earthquake to clarify the mechanism of the lining damage and the effect of the countermeasures."

Jan 1, 2016

By J. DuCarme, A. Smith, M. Reyes

"A magnetic proximity detection system is mounted on a mobile mining machine to prevent underground workers from being pinned or struck by machine motion. The system generates magnetic fields around the machine to determine safe working distances. The minerworn component measures the magnetic field in order to approximate location. Large masses of steel, such as those from mining equipment, can alter the magnetic field distribution. This affects the locational accuracy of the system, thus adversely impacting worker safety. To examine this problem, U.S. National Institute for Occupational Safety and Health researchers developed a method and test system to study the influence of a steel mass on the magnetic field distribution. The results show that a steel plate can strengthen the magnetic field perpendicular to the generator by up to 40 percent. Furthermore, they show that the degree of the influence on the field distribution is a function of distance. The results from this study can be used to further develop and improve the performance and reliability of electromagnetic proximity detection systems used in underground mining applications.IntroductionOn average, 250 miners are injured every year, and 43 miners were reported to be killed by striking or pinning accidents involving continuous mining machines in the United States between 1984 and 2015, according to the U.S. Mine Safety and Health Administration (MSHA, 2015). Continuous mining machines are large mobile machines used to mechanically cut coal in underground mines. These machines weigh approximately 60 t (132,000 lb) each. Although modern continuous mining machines can be remotely controlled, operators still need to be close to the machine primarily because of the low visibility and wide blind spots of the underground working environment.The MSHA promulgated a final regulation in 2015 that requires the use of proximity detection systems on all continuous mining machines except fullface machines. MSHA has approved five such systems to be intrinsically safe for use in underground coal mines: (1) Strata Worldwide’s HazardAvert System, (2) Frederick Mining’s Model 200 HazardAvert Detection System, (3) Nautilus International’s Coal-Buddy System, (4) Matrix Design Group’s M3- 1000/Joy Global SmartZone Gen 1 and (5) Matrix Design Group’s IntelliZone/ Joy Global SmartZone Gen 2."

Jan 6, 2018

By Phillip J. Maddex

Transportation is a major part of yours in the industrial minerals industry. Whereas federal income taxes merely take 50 per cent of your firms profits, transportation cost may take 50 per cent of the gross realization - selling price plus transportation - on your product, f. o. b. customers plant.

Jan 1, 1969

By Jeffery Denit, Steve Hoffman, Van Housman

The Environmental Protection Agency (EPA) is in the early stages of developing a national mining waste program. Our goal is to develop a mining waste program that will be state implemented, multimedia in nature, flexible, utilize and enhance existing state programs, and protect the environment. The Agency appreciates the cooperation the mining industry is providing through its participation in the Policy Dialogue committee on Mining and by providing the Agency with technical data. The following is a discussion of what led to the development of a national mining waste program, the agenda initiative to evaluate Toxic Substances Control Act authority in phosphate manufacturing, and the important steps being taken through the Policy Dialogue process to frame and discuss issues. EXTRACTION AND BENEFICIATION OF ORES The Resource Conservation and Recovery Act of 1976 (RCRA) and subsequent amendments created a framework for the regulation of hazardous wastes under Subtitle C and nonhazardous waste under Subtitle D. In 1978, initial regulations were proposed for hazardous waste management units under RCRA. These identified a universe of special wastes that were large volume, low hazard and less amenable to Subtitle C control techniques. EPA noted that waste materials from the "extraction, beneficiation and processing of ores and minerals m fit these criteria. In October 1980, Section 3001 of RCRA was amended. This Bevill amendment excluded solid waste from the extraction, beneficiation and processing of ores and minerals from regulatory control under RCRA's hazardous waste Subtitle C. This was done pending a report to Congress and a regulatory determination regarding the Subtitle C status of these wastes. Thus in November 1980, EPA published an interim final amendment to the RCRA Subtitle C regulations to reflect the Bevill amendment. RCRA requires EPA to perform studies and make reports to Congress regarding the management methods and potential hazards of managing waste. RCRA also calls for a regulatory determination regarding whether Subtitle C (hazardous) or D (non- hazardous) controls are warranted for these wastes. In December 1985, EPA submitted a report to congress entitled, “Wastes from the Extraction and Beneficiation of Metallic Ores, Phosphate Rock, Asbestos, Overburden from Uranium Mining and Oil Shale." In that report, EPA found that some mining wastes exhibit hazardous characteristics, that the range of risk from mining waste is broad, and that waste management practices have caused environmental damage. In July 1986, EPA published a regulatory determination based on information gathered in the 1985 report to Congress and comments from interested parties. In the report, EPA concluded that RCRA Subtitle C regulation of extraction and beneficiation wastes was unwarranted because mining wastes tend to be disposed of in arid climates, waste volumes are high, and facilities and wastes are located in sparsely

Jan 1, 1992

By Wenming Wang, Edgar E. Vidal, Scott A. Shuey, Patrick R. Taylor, Judith C. Gomez

Introduction In modern society, vanadium is defined as a strategic metal. Some 90% of the global consumption is used as an alloying agent for carbon steels, tool steels, and high-strength low-alloy steels (particularly for pipelines). Advanced titanium-aluminum-vanadium alloys are seeing application in the aerospace industry. Small but ever growing amounts are finding application as catalysts or in electronics. New uses are continually being discovered for this metal. One example of a new application is the vanadium-redox battery for use in generation plants and back-up power sources. Vanadium is found in a large number of minerals, of which the most important are carnotite, roscoelite, vanadinite, mottramite, and patronite. Just over a third of the world's vanadium is produced as a primary product; the balance is a by-product of the iron and steel, oil refining, power generation and uranium enrichment industries. Vanadium can also be sourced by recycling spent catalysts from the petrochemical industry and ash produced by the combustion of oil emulsion in power stations. However, recycling activities are believed to account for only a small amount of total world supply. Vanadium is recovered from these ores largely as the pentoxide (V2O5) [1]. The major sources of vanadium-bearing magnetite ores are scattered throughout Australia, China, Russia, and South Africa. Current estimates of world’s Proven & Probable vanadium reserves are of the order of 41.3 million tones [2, 3]. Commercial vanadium-bearing titaniferous magnetite deposits can be found in Kachkanar, Russia; Pan Zhihua, China; Bushveld, South Africa; and Windimurra, Western Australia [4]. Other deposits have been found in New Zealand, Canada, and India, among other countries. Vanadium consumption in the steel sector has increased some 7% per ton of steel over the last 10 years as new alloying applications have been found to improve steel's strength-to-weight ratio. Future demand from the aerospace and nuclear industries for non-ferrous vanadium alloys such as titanium and super-alloys is also likely to grow. Vanadium is usually added in the form of ferrovanadium, a vanadium-iron alloy. Vanadium compounds, especially the pentoxide form, are used in the ceramics, glass, and dye industries, and are also important as catalysts in the chemical industry. While established approaches may be used at an industrial scale to treat vanadium-bearing titaniferous magnetite ores in several countries, new alternatives are being developed worldwide. This review will give short overview of the treatment of vanadium-bearing titaniferous magnetite ores, an overview of direct reduction and direct smelting processes and an approach to determine technical alternatives for the property.

Jan 1, 2005

By Harry M. Castrantas, James L. Manganaro, Craig W. Rautiola, James Carmichael

Caro's acid (peroxymonosulfuric acid) was successfully field tested as a cyanide detoxification agent at a North American gold mine. An on-site FMC generator injected Caro's acid into a mill tailings slurry sump. The WAD cN-(weakly acid dissociable plus free cN-) was reduced from 40-108 ppm to below the target level of 20 ppm using a 1/1 mole ratio of CA (Caro's acid) /CN-. At an inlet CA/CN-mole ratio of 1.8/1, WAD CN­concentrations as low as 4 ppm cN-were achieved. Raw material costs for the cyanide detoxification were cut by 60% compared to using hydrogen peroxide (H202) alone. Detoxification time with Caro's acid was much faster compared to H202. This resulted in completion of detoxification before the treated slurry reached the tailings pond thereby substantially reducing the probability of wildlife fatalities.

Jan 1, 1993

By Gerrit V. R. Goodman, Charles D. Taylor

A technique was developed to determine the fraction of air recirculated from the scrubber exhaust toward the face and the fraction of gas captured by the scrubber. To determine these two values, a series of tests was required. In the first test, gas was released at the face area and concentrations measured at the scrubber exhaust. In the second test, gas was released directly into the scrubber with concentrations again measured in the scrubber exhaust. The simultaneous solution of two independent flow expressions gave values of recirculation and scrubber capture. A series of tests was conducted with various combinations of scrubber flow, curtain flow, setback distance, and machine location. Statistical analyses then were conducted to determine those factors which influenced the levels of scrubber recirculation and scrubber capture in a deep cut. INTRODUCTION As cutting depths increase, the trend is toward the use of blowing face ventilation systems. With these ventilation systems, the potential exists for recirculation between the scrubber exhaust and the intake air stream. One concern is that methane gas, having been removed from the face area, is subsequently recirculated back into the intake airflow. Under these conditions, methane-laden air could be substituted for fresh intake air, leading to increased methane concentrations at the face. There is currently no standard for recirculation between the scrubber and intake airflows. The implied understanding of the Mine Safety and Health Administration (MSHA) is, and has always been, that any recirculation of ventilation air is unacceptable. To minimize recirculation potential, MSHA suggests that operators maintain scrubber and curtain flows within 0.47 m3/sec (1000 cfm) of each other. Given that recirculation may occur in some circumstances, the question arises as to how much recirculation constitutes a hazard for the face workers. Unfortunately, there is currently insufficient information to answer this. Emphasis must instead be placed on means to quantify the amount of recirculation between the scrubber and face area. Methods must also be examined to control this phenomenon. This paper presents a technique for quantifying recirculation and scrubber capture levels in a blowing face ventilation system. Several ventilation parameters are investigated to determine their effects on these levels. DEVELOPMENT OF RECIRCULATION EXPRESSIONS One way to measure airflow quantities at a point near the face would be to measure the gas flow rate Qgas, and gas concentration c at that location. The airflow Qair, would be simply the ratio of these two values, Qair, = Qgas/c. Although gas concentration values, c, can be obtained easily with existing gas monitoring equipment, it is more difficult to obtain gas flow readings, Qgas, at specific locations. To obtain these values of Qgas, another method was needed. Previous work in this area was conducted by Kissell and Bielicki (1975). However, the calculations in their model assumed a constant gas concentration in the region around the continuous miner. In a deep cut, it is questionable that gas concentrations would remain constant or uniform around the mining machine. The technique presented here does not rely on this assumption. It instead assumes that the gas concentration in the scrubber exhaust remains constant. A quantity of gas released at the cutting face either flows into the scrubber inlets or bypasses the inlets and flows around the off-curtain side (in this example, the right side) of the continuous miner (Figure 1). The fraction of the face gas that flows

Jan 1, 1993

By Joseph G. Carleton

INTRODUCTION The increasing concern for the environment may well present far more opportunities than problems for those involved in all phases of tunneling. All too frequently in the past, environmentalists and their concerns have been cast in a negative light, as obstacles to be overcome. Often forgotten is the fact that these same environmental concerns have created a rapidly increasing demand for new tunnels. Tunnels for rapid transit projects, clean water supply, and sewage treatment have been given a boost because of environmentalists' concerns about overuse of automobiles, inadequate water supplies, and improper sewage disposal. Concurrent with increasing use of tunnels to help solve or alleviate some of our environmental problems is an obligation not to create new ones in the process. Concerns which we feel responsible tunnel owners, engineers, and contractors should address themselves to include: (1) Minimum energy consumption, both during construction and in operation of the completed project; (2) proper storage and/or disposal of the excavated material; (3) minimum disruption during the construction process - noise, traffic, unnecessarily unsightly work areas, and possible weakening of foundations of nearby structures; and (4) a finished project consistent with community and environmental goals. We are especially concerned about two things. First, the longrun implications of a project -- what's good for a few people in the short-run may be bad for most of the people in the long-run. Cutting corners to save a little money now is false economy. Second, the fact that ultimately we all share the same earth -- its water, air,

Jan 1, 1974

By J. Espí

The mineral price assigned in mining project design is critical to determining the economic feasibility of a project. Nevertheless, although it is not difficult to find literature about market metal prices, it is much more complicated to achieve a specific methodology for calculating the value or which justifications are appropriate to include. This study presents an analysis of various methods for selecting metal prices and investigates the mechanisms and motives underlying price selections. The results describe various attitudes adopted by the designers of mining investment projects, and how the price can be determined not just by means of forecasting but also by consideration of other relevant parameters.

Aug 1, 2013

By E. Allen Hendt

It is a pleasure to be invited to speak before a gathering of executives representing America's leading mineral companies, I welcome this opportunity, particularly because it comes at an important period in the development of U.S. commodity policy. This morning, I discussed our general commodity policy primarily in the. Context of the north-south dialogue between developed and developing countries. This afternoon, I would like to focus more specifically on potential cartel activity and U.S. mineral import dependence.

Jan 1, 1978

By G. P. Larson

We define a specialized mineral market as follows: Specialized markets occur where a low volume of a given mineral is used to convey a large benefit to a specific product. Sales of these value added minerals to small markets generally require a different marketing approach than bulk or commodity markets for traditional minerals. Specialized markets are differentiated by several characteristics as listed in Table 1. [Table 1-Characteristics of Specialized Markets 1. Long-term sample evaluation 2. Small volume markets 3. Highly controlled properties 4. Customized specifications 5. Technical selling effort] Many of the specialized markets require long term evaluations before sales can be made. This can vary greatly depending on the type of industry and ultimate end-use of the final product. In some cases, complete evaluations may take from several weeks to years. Length of sample evaluation has no relationship to size of market. That is, the total market may be quite small or fairly large (e.g. from a few hundred pounds to a few million pounds). Uniformity of value added minerals from lot to lot is an extremely important characteristic for these markets. Variations that are of no consequence to one industry (or application) cannot be tolerated in another. This has led to customized specifications and test procedures for specific markets and applications. Because of the greater uniformity and customized specifications, the need for greater technical selling effort is required. This is particularly true in the initial developmental phases and contacts as well as in maintaining the account after the initial order. A small entrepreneurial organization can be used to advantage to achieve goals of sales and profit to these types of markets. The large commodity or bulk producer's sales and marketing organizations are not ordinarily equipped to give the necessary service or technical assistance to the specialized markets. The organization usually required for this type of marketing is given in Table 2. [Table 2- Specialized Marketing Organization Requirements 1. Flexible approach to technical and marketing problems 2. Versatile background in a broad range of industries 3. Laboratory backup when necessary 4. Marketing expertise 5. Technically competent management] In developing specialized markets, a flexible approach to both technical and marketing problems is necessary in understanding the needs and requirements of the industry and the applications involved. This flexibility is also helpful in adapting existing products to new market areas. Having knowledge of a range of industries as broad as possible can be very helpful. It often happens that a product developed in one area or industry can lead to its application in a different area with excellent results. Laboratory assistance for a wide range of tests and test procedures is an important asset in any development program for specialized markets. Laboratories can also assist in competitive evaluations. Marketing expertise and a management with some degree of technical understanding are necessary in to assign proper cost/ benefit ratios to a proposed new product or application of existing products. This is important since the total market volume can be small and the time required for initial contact to first sale can often be lengthy. Also, management's technical and marketing expertise is required in evaluating all possible options that can be considered viable when an application is presented. Once an organization of this type is in place, it is then possible to determine the needs of the marketplace, including when various minerals might have to be customized to fill those needs. There are generally two methods of marketing, as noted in Table 3. [Table 3- Method of Marketing 1. Product Driven -Develop a product with certain desirable properties and try to find a market to utilize those properties. 2. Market Driven -Know market well enough that when a need arises, it is possible to identify a product that will satisfy the need.] These approaches are not mutually exclusive and can be used at the same time. Marketing a value added mineral generally requires the "market driven" approach. Hence, the importance of a knowledgeable management as outlined above. To determine where needs and opportunities exist, several approaches can be used. Table4 lists some of the methods employed.

Jan 1, 1993

By C. S. Simons

The aphorism that provided the title of this paper is probably a couple of hundred years old, but it still expresses a fundamental truth in the metals industry. This truth will be illustrated through a brief review of the major developments in the extractive metallurgy of the oxidized ores of nickel - the "laterite" ores. While the details to be discussed are for the most part specific to nickel, a close parallel with other commodities - particularly in recent years - will be apparent even to those whose interest in nickel itself is slight. Thus it is hoped that this paper will be stimulating, at the least, to anyone who is concerned with the implementation of process improvement, "Invention" in the present context means any change from "conventional" process technology that shows a reasonable chance of reducing costs, increasing revenues, or both, in the production of a commodity. This can be anything from a simple rearrangement of flowsheet steps to a completely different basis for processing. And the result may reduce costs by more efficient use of energy or labor or reagents; may increase revenues by better recovery of the primary product or by introducing the recovery of previously ignored by-products; may insure sales volume (and thereby cash flow) through higher product purity or an improved product form. "Necessity" is the perceived need to attain at least one of these classes of results. This perception of necessity, however, varies widely from management to management and from project to project.

Jan 1, 1983

By V. O. Tenorio, D. Tolmachoff, K. Willa Brown, K. J. Kingsbury, J. B. Nickels, G. J. Nail

A major design feature to consider from the initial pioneering works until reaching full mine production of icy regolith at the South Pole of Moon will be the ramp. This will allow the access of equipment and personnel in and out of the excavation area. Although most of the requirements considered when designing a ramp on the Earth are similar, the fact of working in low gravity, with zero atmosphere, the potential exposure to high radiation, extreme temperature levels and drastic changes of illumination, from intense light to total darkness, are new factors to be included. Transversal sections are obtained according to the progression sequence of the production levels, with changes in length, gradient, friction factor of the terrain and curvature when required by the location characteristics and the specification of the equipment utilized. A MATLAB script was developed to calculate all the variables, in order to obtain 3D generated surfaces from the range of possible profiles.

Mar 2, 2022

By G. J. Simandl

Jade is a commercial term encompassing green, white, black or yellow-brown jadeitite and nephrite. Jadeitite consists of Na-rich pyroxene, whereas nephrite consists of prismatic to acicular amphiboles of the tremolite-actinolite series forming bundles that are randomly oriented and interlocked. Nephrite is tougher (harder to break) than jadeitite. Its fracture strength is about 200 MN/m2 whereas that of jadeitite is about 100 MN/m2. On the other hand, jadeitite has a higher hardness (7 compared to 6.5 on the Mohs scale). There are over fifty known nephrite occurrences in British Columbia (B.C.). These occurrences consist of individual blocks, boulder fields, talus blocks and in situ occurrences. Most of the in situ occurrences are lens or cigar shaped. They occur at, or near the contact of ultramafic/mafic rocks (mainly serpentinites) with cherts, and other metasedimentary or igneous felsic rocks of Mississippian to Jurassic oceanic terranes such as Cache Creek and Slide Mountain. These contacts are commonly interpreted as shear/fault related. In general, it is believed that the B.C. nephrite formed by metasomatic exchange between ultramafic and silica-bearing rocks. Impurities in B.C. nephrite are spinel group minerals (chromite, magnetite, picolite), diopside, uvarovite, titanite, chlorite, and talc. Jadeitite is slightly denser than nephrite and good quality material sinks in methyl iodine. There are no known jadeitite occurrences of economic interest in B.C., but there are at least four geographic areas where favorable lithologies, and metamorphic conditions (Pn) required for the formation of jadeitite coincide. These are Bridge River, Pinchi Lake, Dease Lake, and Jennings River. These areas are known to contain small concentrations of jadeite, or are characterized by blueschist or eclogite-grade metamorphic conditions. Rhodonite and pyroxmangite are MnSi03 polymorphs. These minerals are pyroxenoids and are macroscopically and microscopically very similar. For brevity, both are grouped together under the term "rhodonite". Most of the B.C. occurrences are hosted by late Paleozoic chert sequences and are lens shaped and concordant. The common association of rhodonite with iron formations, jasperoids, and/or volcanogenic sulphide deposits in southwestern B.C. permits the delineation of favorable horizons using magnetic or electro-magnetic geophysical methods. Geographic associations between manganese showings and sulphide deposits, and the hydrothermal chemical signature of the rhodonite occurrences from this area, suggest a genetic link between rhodonite and volcanogenic sulphide deposits. The typical rhodonite rocks consist of rhodonite, pyroxmangite, neotocite, black amorphous Mn-oxides, Mn-bearing garnet, ± epidote, ±chlorite, ±rhodochrosite, ± parakutnah-orite, ± Mn-bearing calcite, ± iron oxides and hydroxides. Garnet ± epidote forms yellow patches and layers within the rhodonite. Within some of the rhodonite occurrences, the garnet is altered to chlorite. Rhodonite-bearing rock is commonly cross cut by secondary manganese oxide veins, creating a characteristic web-like texture. In several localities, the contorted bedding planes are readily recognized. Mn-calcite and quartz also crosscut rhodonite. Rhodonite deposits hosted by high grade metamorphic rocks may contain pyroxmangite. Rhodonite is an important gemstone and ornamental stone in B.C., second only to nephrite in dollar value. B.C. nephrite and rhodonite have been used for the past 100 years in local jewelry and ornamental applications. More recently they have been used in table tops, and they have potential as upscale materials in tile-making. There may be a market for tiles made from lower grade materials that were previously extracted and stockpiled. The prices of nephrite, jadeitite, and rhodonite vary widely with quality, but gem and ornamental grade stones are relatively highly priced materials and they trade world-wide.

Jan 1, 2001

By N. R. Sainath

This paper discusses the results of a laboratory investigation carried out to study the microscale flow characteristics of copper ores and the variation in flow behavior resulting from flow of leach solution. Fractures in 1.5 and 4 inch diameter cores were mapped by visual inspection. The cores were stressed in a triaxial stress field representative of in situ conditions. The permeability of the samples to water was then estimated. The samples were exposed to 20 g/l sulfuric acid and the experiment repeated. The Permeability of unleached samples ranges from 10-1 to 10-19 m2 and it increases as leaching progresses. The porosity variation and the rate of recovery of copper from the specimen during leaching were also studied.

Jan 1, 1991

By Douglas J. Cork

Biohydrometallurgica1 processes in the areas of coal desulfurization (Hoffman, M.R., et al., 1981) and recovery of metals from metal sulfide ores (Lundgren, D.G. and Malouf E.E., 1983) are well known. In addition other areas of potential interest to the mining industries have been outlined (Spisak, J.F., 1979). For instance, scientists involved in this interdisciplinary field have endeavored to apply microorganisms to the problem of effluent sulfate disposal. This chapter assesses the feasibility of utilizing a particular two stage anaerobic microbial process to convert effluent sulfate to orthorhombic sulfur. Strong emphasis is given to the possibility of substituting this bioprocess for alternative gypsum synthesis and disposal methodologies commonly practiced by companies which emphasize sulfuric acid or ammonium sulfate leaching processes.

Jan 1, 1985

By M. Stefanakis, M. Errington, A. Kontopoulos, J. M. Prevosteau, K. Adam

The Olympias arsenical pyrite concentrate assaying 25 g/t Au, 40% S, 40% Fe and 12% As is highly refractory in nature; an oxidation pretreatment step is required to liberate gold and render it amenable to cyanidation. In the present study mineralogical analysis techniques including Image Analysis, SEM, EPMA, SIMS, Mossbauer, ICP/MS, etc., have been employed in order to investigate the mode of gold occurrence within the Olympias pyrites. Bacterial oxidation was used as a case pretreatment route and bacterially leached products were examined under SEM. The mineralogical observations and the relevant metallurgical and cyanidation test data were combined to establish a correlation between the mineralogical characteristics of the raw and oxidised products and conditions prevailing over the oxidative pretreatment step and the gold liberation achieved.

Jan 1, 1990

By P. Huttagosol

The use of computer models to design ultimate pit limits during feasibility study and long range mine planning is becoming a significant practice in open pit mining. One of the problems in determining optimal ultimate pit limits using true optimization techniques has been they require a great deal of computer memory and execution time. In this paper, the maximum closure of a graph, which is a true optimizing model developed by Lerchs and Grossmann, is modified for solving ultimate pit limit problems. By using some properties of the original L&G graph algorithm, the tree configuration can be reduced to only connections between positive ore nodes. The modified algorithm is shown to require less memory and processing time while still yielding an optimal solution.

Jan 1, 1989

By Raj K. Rajamani, M. K. Abd El-Rehman

The planetary mill is very much suited for the ultra-fine grinding of mineral fillers. Ultra-fine grinding here refers to grinding powders to a size range 5-1 0 rnicrons. Such powders enhance the quality of the final product. The operation of a specially built planetary mill is described. It is shown that a target size of 5 rnicrons can be reached in a few hours using the dual drive planetary mill. A centrifugal field of 37G is generated by the gyration arm of the mill. The design allows the desired setting of canister critical speed. The ultra-fine grinding of alumina, titanium dioxide, hematite, magnetite, kaolin and silicon carbide are described. Also, the continuous operation of the mill is shown.

Jan 1, 2003