Search Documents

By James T. Finley

Profit, product quality, speed of operations, reliability, operator confidence, safety and environmental improvements have all been enhanced as a result of the recently completed maintenance, renovation and construction program at Crown Central Petroleum Corporation?s (Crown?s) coke calcining unit at its Pasadena, Texas refinery. (Figure 1) BACKGROUND The calcining unit was built in 1969 - 1970 and has been operated continuously. Approximately 400 to 500 TPD of high quality metallurgical grade coke is manufactured, stored, and shipped to consumers. About 1/2 of the feed stock to the calciner is manufactured in Crown's coking unit and the remainder is received, via barges, from various sources. The green coke is off loaded from the barges with a conventional grab crane that discharges into a small travelling hopper over a conveyor belt that feeds a radial stacker, which forms a stockpile on the ground. The green coke, from the coking unit at the refinery, is moved to the calcining unit with front end loaders. Reclaiming from the stockpiles is also done with front end loaders. The coke is primarily handled by covered conveyor belts. The finished product is stored in steel silos and can be shipped via railroad cars, but the majority of it is shipped out in ocean going bulk carriers. Maintenance work in the calcining unit is performed by Crown's refinery maintenance department on an as needed, on call basis.

Jan 1, 1983

By G. C. Knutsen

The Post deposit is located in Eureka County, Nevada, about 37 km (23 miles) northwest of the town of Carlin. Post occurs on the Carlin Trend, a northwest alignment of 14 major gold deposits, each containing more than three tonnes (t) (100 000 ounces) of gold. Deposits of the Carlin Trend are epithermal, sediment-hosted, disseminated gold occurrences, collectively containing more than 622 t (20 million ounces) of gold. Three major gold producers active on the Carlin Trend are Newmont Gold Company (NGC) (12.4 t/400 000 ounces of gold per year), Western States Minerals Corporation (WSMC) and Pancana Minerals joint venture (1.56 t/50 000 ounces of gold per year), and Dee Gold Mining Company (1.4 t/45 000 ounces of gold per year). The Carlin Trend has also been referred to as the Lynn-Railroad Mineral Belt. This district is characterized by open-pit mineable, micron-sized gold, hosted in Paleozoic sedimentary rocks. Six geological subdistricts comprise the Carlin Trend, each characterized by differences in host lithology, structural controls, alteration assemblage, or style of mineralization. The six geologic subdistricts include, from south to north, Bullion (Railroad), Rain, Maggie Creek, Lynn, Bluestar-Goldstrike, and Bootstrap. With the exception of the Bullion subdistrict, which was primarily a producer of base metals, each sub-district contained mineable reserves in excess of 31 t (one million ounces) of gold.

Jan 1, 1987

By Jean Dupere

Mr. Chairman, Ladies and Gentlemen, I'd like to take just a moment of your time before we examine the current position of the asbestos industry and its market outlook to take a searching look at the product itself. I feel that if we are to understand the problems that beset this basic mining and manufacturing industry and, more important, if we are to appreciate the solutions to these problems that I plan to put forward in a few moments' time, then we had better look at asbestos from the proper perspective. Asbestos has a unique combination of properties - properties not found in any other natural substance or man-made material. This has resulted in asbestos finding its way - in fact, being welcomed - into literally hundreds of applications.

Jan 1, 1984

By M. Karmis

According to international projections and future energy scenarios, coal will continue to be a prominent fuel for the next 25 years. In fact, in many regions around the world, coal is expected to dominate the electricity sector until the year 2030. At the same time, with instability and volatility of oil prices, coal is also positioned as an alternative feed stock for conversion into liquid fuels. Energy economists maintain that coal liquefaction is viable at crude oil prices of $35 or more per barrel. Depending on technology and coal composition, 1 ton of coal can produce 1 to 4 barrels of oil. Increased coal production and the expanded utilization of coal also raise environmental concerns regarding greenhouse gases and the problem of handling CO2. Carbon sequestration research, currently conducted in many parts of the world, has demonstrated considerable potential for C-storage in unminable coal seams. Such geologic storage, when possible, can also be integrated into an enhanced coal bed methane recovery process Can coal fuel power plants and industrial facilities, provide diesel and other liquids and, at the same, also be used as a medium for permanently storing CO2? This presentation will provide a global perspective on these questions and stress on the need to reconsider, or even redefine, coal as the fuel for the future.

Jan 1, 2006

By K. Kavouridis

The competitiveness of power production from lignite depends on the ability of coal industry to meet CO2 emissions limits, as specified by the Kyoto protocol. According to the National Allocation plan issued by EC, power plants should reduce CO2 emissions to a certain level, other-wise they will be obliged to cover the difference buying CO2 certificates through the Emission Trading Scheme. These charges will increase the operating cost of current units, as well as the investment cost for new units. To predict the increase in the marginal cost of electric power produced from the current plants of Western Macedonia, an emissions factor (CO2 t/MWh) for various units has been computed. Based on the algorithm used, this factor depends on the calorific value of the lignite, the efficiency of the power plant and the oxidation factor of the unit. For lignite plants with efficiency ~37%, CO2 emissions factor ranged from 1.19 t/MWh to 1.32 t/MWh. The increase in the marginal cost of kWh, as compared to the values of CO2 certificates, is higher in units fed with low quality lignite and worsens if the efficiency of the unit is low too. Also the presence of calcareous minerals in lignite increases the CO2 emissions and consequently the cost of power generation.

Jan 1, 2006

By G. Viggiani, J. Bel, H. Wong, N. Losacco, D. Branque

"Within the framework of the European project NeTTUN, the Laboratory of Civil Engineering and Building Sciences of ENTPE in Lyon (France) is in charge of a large experimental campaign to investigate the impact of tunneling on neighbouring piled structures. For this study, an original reduced-scale (around 1:10) physical model of EPBS is used. This ""1g"" laboratory model is able to reproduce the main features of the excavation method. For this new experimental program, the miniature EPBS advances inside a large tank filled with a model soil (dry sand), in which instrumented piles were pre-installed. In this paper, the authors describe briefly the original 3D device and present results concerning the impact of tunneling on a single pile located above the tunnel. Different tunneling face pressure are studied in connection with the practice. Machine parameters, pile solicitations and stress-strain behavior of the soil mass monitored under real time conditions are discussed. INTRODUCTION When tunnels are constructed in urban areas, they often come close to pre-existing structures, such as pile foundations. Perturbations of tunnel construction on these neighbouring structures must be considered during design and construction of the tunnel. Ground movements due to tunnelling may induce bending moments, lateral and vertical loads, settlements and lateral deflections in the piles, which may lead to structural damage or failure of the piles or the supported structure. The interaction between piles and a tunnel in construction is a complex three dimensional problem. To date, several experimental approaches have been carried out to analyse the effects of tunnelling on piled foundations (Bezuijen et al., 1994, Loganathan et al., 2000, Jacobsz et al. 2004, Lee and Basset, 2006, Marshall and Mair, 2011, ). These different studies carried out in the laboratory on 1 g or centrifuged models aim at a better understanding of tunnel - piles interaction and a quantification of the influence of each dominating parameter on the structural responses. Parameters like foundation type (single pile, group of piles) and geometry, relative tunnel – pile position, volume loss induced by tunnelling, ground characteristics, pile loading history were considered. However, most of these experiments were carried out under plane strain conditions by modelling the volume loss due to tunnel excavation by decreasing the tunnel diameter or the radial support pressure. As a result, these models do not adequately account for the variations of settlements both in the longitudinal and the transverse direction, which can induce significant flexional and torsional effects on the structures. These effects are particularly critical and detrimental in the case of historical monuments."

Jan 1, 2016

By Paul M. Keyser

Flotation columns continue to offer improved metallurgical and economic advantages over other flotation methods. Pilot testing at Ozark-Mahoning Co. in Rosiclare, IL led to installation of one 2.3-m-diam (7.5-ft-diam) column for zinc roughing and one 1.1-m-diam (3.5-ft-diam) column for zinc cleaning. This circuit replaced one stage of mechanical roughing-scavenging followed by two stages of cleaner flotation. General Column flotation continues to make inroads into applications traditionally dominated by mechanical flotation cells. For example, columns are becoming more visible as rougher flotation devices. At Royal Mountain King Mine in California, two 2.9-m-diam (9.5-ftdiam) columns are used for rougher flotation of carbon from a gold ore (Orlich et al., 1992). In addition, work performed at BRGM in France demonstrated the superiority of column flotation over mechanical flotation with respect to design of new plants (Morizot et al., 1991). The primary reasons for this acceptance of columns are a general improvement in design, scale-up and operation, as well as improvements in sparger design and performance. With these advances, the full benefits of column flotation can be realized. The benefits of properly designed, aerated and operated flotation columns include lower capital costs, reduced operating costs, fewer processing stages and improved metallurgical performance.

Jan 1, 1993

By John M. Wootten

The development of new coal markets is -t upon the ability to utilize coal in an environmentally acceptable and economically viable fashion. Foremost in the concerns about coal utilization is the impact its combustion has on air pollution. Concerns over environmental issues, such as acid rain, are currently one of the major impediments to the development of new coal markets. The Department of Energy and the Synthetic Fuels Corporation are addressing certain aspects of the development of new technologies for the utilization of coal. However, at the present time, there is a void in the new technology development process. That void is the step from proof- of-concept to commercial demonstration. Congress has established the Clean Coal Technology Fund at a level of $750 million to fill this void. The Department of Energy, in a solicitation of interest, received over 175 proposals for commercial demonstrations of clean coal technologies. A review of these solicitations indicates that $1.2 billion worth of research could be accomplished with a federal cost sharing of $425 million or 35 percent of the total. Industry has indicated, through this response, its willingness to invest its limited funds on projects it feels have the greatest potential for the clean use of coal. What must now occur is that Congress must appropriate the monies from the fund to initiate the commercialization of these clean coal techno1ogies.

Jan 1, 1986

By James L. Hendrix, David Castillo

Cyanidation is one of the most common practices used in the extraction of gold and silver. One method of application is heap or dump leaching which entails the leaching of the gold or silver ore by spraying or dripping a cyanide lixiviant over the ore and collecting the effluent. The ore is placed on what is known as a leach pad system. A typical leach pad system consists of a foundation, a leakaqe detection system, a liner, and a cover layer (Strachan and van Zyl, 1988). There are many types of liners available for use. The type of liner depends upon what type leaching pad system us used. Generally, leaching pad systems can be categorized into two types: an expandable pad and a reusable pad. An expandable pad exposes the liner to the elements only in the initial stages of ore placement on the leach pad system. A reusable pad exposes the liner to the elements on a periodic basis. In addition to the exposure to the elements, the liner is also under the stress of the ore placed on it and the stress of the vehicular traffic across it. These stresses and exposure to the elements are the major causes of liner failures, which can appear as punctures, tears, cracks, and deterioration. Because of the possibility of the failure of the pads to contain cyanide-laden solutions the designs for liners of pads and ponds have become more and more stringent. Currently, though, there is some recognition that in some locales such stringent design criteria may not be required (Chatwin, 1989). Some soils have significant cyanide attenuation and degradation capacity. It has been found that soils containing carbon- aceous materia1 wi11 remove cyanide from solutions percolating through them (Chatwin, 1989). Of course metallurgists have long recognized the deleterious effect of carbonaceous material in the mill circuit. Sheridan, et a1 (1988) have shown that WAD cyanide is detected in the effluent of a 2 m column filled with ground carbonaceous ore only after it had been continuously washed with greater than 9 pore volumes of NaCN solution. It was decided to examine the potential of successfully attenuating cyanide by placing an organic material layer between a 1iner and the prepared soil base. One consideration for the selection of the organic material was cost. Sawmill wastes, ground agricultural wastes (such as corn cobs), and other organic wastes were considered. But the first waste to be tested was a product found at any metropolitan area, sewage sludge.

Jan 1, 1990

By Erick F. Weiland, John W. Lindemann

Introduction Minerals exploration is one step in the mining industry's task of providing raw materials to basic industries. The industry's provision of raw materials involves identifying and evaluating resources, converting them to reserves, and intelligent, economic exploitation of these reserves. The mineral process focuses on identification and evaluation. Reserves are ore bodies and ore bodies are, by definition, wasting assets. Therefore, if an adequate provision of raw materials to basic industry is to continue, these wasting assets (ore bodies) must be replaced with new or different reserves as current reserves are depleted. Minerals exploration is a geologic problem and is fundamentally deductive, flowing from the general to the specific. Past exploration methods and philosophy have amply supplied the resources to meet the demands of an industrial society. During the past decade, however, the framework where mineral resources were identified, defined, and evaluated has changed. Mineral explorationists no longer can rely solely on the successful past methods to provide the necessary resources for our complex society. Productive explorationists must effectively and efficiently use tools and procedures that will maximize exploration efforts. Past tools need not be abandoned, but should be critically reviewed and revised in light of current scientific knowledge and technical advances. Future explorationists will view their craft not as a single discipline, but as a thoughtful integration of geophysics, geochemistry, and geostatistics for solving interrelated problems. This integration of the geosciences will lead to successful mineral exploration. Not only will the productive explorationist generate new information, he will master the use of existing data for identifying and evaluating a mineral resource. The mineral exploration process consists of incentives, ideas, finance, area, staff, time, and luck. The exploration process that stems from the interaction of these elements has three stages, each bound by a major decision point. They are selection, reconnaissance, and definition. Subsequent evaluation and exploitation phases are considered more the function of mining engineers than the exploration geologist. Mineral exploration endeavors that have been productive have three attributes fundamental to success: commitment, competence, and persistence. Commitment Commitment is believing that exploring for mineral resources is worth performing. While the mining industry is the focus of this commitment, government and society must also be committed to the concept of mineral reserve identification through exploration activity. Government demonstrates its commitment by providing access to land for exploration and, if it is successful, exploitation can take place. Realistic legislation relating to taxation, land use, reclamation, and environmental constraints is indicative of government commitment to intelligent resource use. The public must come to terms with mineral resource evaluation and extraction. Without some form of commitment from the public, availability of mineral resources vital to basic industry will be largely in the control of a foreign and potentially unstable mining industry. Commitment to a mineral resource identification-evaluation-extraction system must be shared equally by government, society, and the minerals industry. The scope and direction of this commitment varies, with the industry's commitment to explore for mineral resources being the most apparent. Industry commitment is the belief at all levels of exploration (from senior corporate executives to individual field and support staff) that exploration is worth performing, that exploration goals can be met, and that their particular organization is the best and the only group that can successfully accomplish the project. Commitment can be considered at three

Jan 11, 1983

By R. L. Pozzo

A previous investigation showed that corrosion currents estimated from polarization curves for the pyrrhotite-grinding media system under abrasion correlated well with corrosion currents estimated from marked ball wear test data by applying the Faraday's Law. Freshly abraded metal debris were magnetically attracted to pyrrhotite and lowered the rest potentials of the mineral particles, thereby affecting the corrosive wear. The investigation was extended to explore the interactions between a nonmagnetic sulfide mineral, pyrite, and abraded metal debris and their effects on the corrosive wear mechanism. The electrochemical behavior of a three-electrode system involving pyrrhotite, pyrite and grinding media was also investigated as a first step towards elucidating the nature of interactions that occur in the grinding of complex sulfide ores.

Jan 1, 1987

By R. Sharma

The heterogeneous distributions of nodule sizes, cover-ages and abundances and the variability of their burial und association with sediments and rock outcrops on the seafloor have emerged as crucial parameters in considering the exploitation potential of the manganese nodules in the central part of the Indian Ocean. Nodules with the long axis measuring from 20 and 40 mm (0.8 and 1.6 in.) account for nearly 60% to 70% of those evaluated from photographic and grab-sample data. In addition, 75% of the nodules (by weight) are between 20 and 60 mm (0.8 to 2.4 in.). The distribution of nodules with abundances ranging from 1 to 20 kg/m2 as well as coverages of 1 % to 90% on the seafloor are important considerations in demarcating the potential areas for nodule mining. The mining of areas with higher concentrations of nodules, such as along slopes associated with less sediment, would result in the enhanced recovery of nodules compared to areas with low nodule concentrations, such as in valleys and plains where thick sediment covers occur. The mining head will encounter substrates such as hard rock exposures, either with or without Fe-Mn encrustations, as well as soft sediment layers in the nodule fields. It must be able to collect buried nodules under sediment cover, and it must be able to negotiate uphill and downhill slopes in mining areas. Mapping prior to mining must delineate areas to he avoided and must define locations to be mined. The requirements suggest that the nodule collector must be a dynamic (active) system with sensors to detect areas of potential nodule concentrations, as well as features that are hazardous (or unfavorable) for mining operations.

Jan 1, 1999

By D. R. Nagaraj

Depression of copper sulfides followed by MoS2 flotation is the most commonly practiced technique for Cu-MO separation. Although numerous organic depressants have been developed in the past, a majority of the currently used copper depressants are inorganic compounds (ex. NaHS, Nokes reagent, etc.). A unique advantage of organic depressants over the inorganic compounds is the potential versatility for design of the organic molecule to suit many requirements. The present study was initiated to systematically investigate the structure- activity relationships for a large number of organic complexing agents in comparison with the commonly used inorganic depressants that are often inefficient and hazardous. The results obtained in this study are discussed in light of the useful correlation obtained between practical solution redox potential and depressant activity. Several requirements, such as the presence of an active -SH and hydrophilic -OH or -COOH in the organic molecule, are identified for a reagent to be a satisfactory depressant. Some preliminary results on the desorbability (or destruction) of collector coating on the sulfide surfaces in the non-xanthate collector systems are also discussed.

Jan 1, 1983

By M. G. Skowroski, G. G. Eichholz, J. P. Ambrose

Introduction It has long been known that there are extensive deposits of phosphate-bearing deposits in the Coastal Plain of Georgia in many locations that are similar to those being mined commercially in central Florida. A major drilling program was conducted in 1966-67 by the Georgia Geological Survey (GGS). The economic potential of some of the material uncovered was evaluated at that time by a team at Georgia Institute of Technology led by Dr. J.E. Husted. There were some promising results. Since then, there has been little commercial interest in pursuing this matter, though the potential for development remains. In the long term, Georgia's phosphorite deposits could be a major source of income to the state if they were commercially processed. Phosphorite deposits contain significant levels of uranium and thorium. Uranium concentrations in Florida phosphate aggregates have been found to be 120 to 140 ppm. The presence of high concentrations of uranium means that there is a small but finite concentration of radium, which subsequently leads to radon gas emanation. It is the radon emanation and its progeny that may pose the largest health problem in many types of mining. Surface mining operations can possibly elevate the radon and radon daughter concentration in the vicinity. There is always some public concern whether any increase in the radon concentration in the atmosphere by mining (surface mining in the phosphorite case) could elevate the risk of cancer in the nearby population. At the present time, a great deal of attention has been devoted to the possible health effects of radon and its decay products in the inhaled air in mines and inside buildings built on mill tailings or uranium-bearing rock (Gesell and Lowder, 1980). Several evaluations have been published on the potential health effects of the Florida phosphate operations (Guimond and Windham, 1975; Roessler et al., 1980; Travis et al., 1979) and for buildings incorporating phosphate slag aggregates (Kahn, Eichholz, and Clarke, 1983; Roessler, Roessler, and Bolch, 1983). They all indicate that such potential effects are small, but tangible, compared with other radiation effects, for instance in the nuclear industry (Cohen, 1981). In view of the current concern, especially by the US Environmental Protection Agency (EPA), with the radiological consequences of large-scale mining of uranium-bearing phosphate rock (Guimond and Windham, 1975), it was decided to assess the potential radiological consequences if the Georgia deposits were developed. This paper presents an attempt to estimate the magnitude of any radon-based health effects that might arise from future mining operations in selected areas of the Georgia coastal region. To do this, a calculational model was developed that took into account the mining operations themselves, the atmospheric dispersion of the radon released, and the radon daughter concentrations in nearby towns. The model was applied to both extremes. The first application was a hypothetical mining operation in Echols County. Echols County is very sparsely populated and, unless living very close to the site, a person would probably experience little radiation exposure, if any. The model tries to prove this point. The second application was at a site near Savannah, Georgia. Both sites contain economically feasible phosphorite deposits and were not entirely hypothetical in that sense. Site selection In the course of the South Georgia Minerals Program (Furcron, 1967), an extensive series of drill core samples had been collected from various mineral occurrences in the coastal plain. It was found that the cores from the previous drilling program (Furcron, 1967), though carefully preserved, were not readily accessible. But the GGS reports did contain gamma logs of all the holes surveyed. With the cooperation of Dr. Neal Shapiro of the Survey, some core samples were selected and assayed, and used to calibrate the gamma log data. Samples from locations known to have detectable radioactivity were screened and counted. Their measured uranium content was used to calibrate the gamma log profiles for those same holes as obtained by the GGS. On this basis, two of the higher-level sites were selected and the calibration was used to obtain integrated uranium concentrations over the length of the borehole. It is customary to describe radon and radon-daughter concentrations in "working levels" (WL), where one WL represents a concentration of radon daughters capable of releasing 130 000 MeV of alpha particles, equivalent to 100 pCi of radon in equilibrium with its daughters per liter of air. A representative concentration is 0.15 WL, below which radon levels are widely considered to be negligible. For the mine sites selected, the surface area and rock volume were determined to estimate their radon content. Working-level values were then estimated for the assumed radon release from the crushed ore and the exposed surfaces of the mine pit. According to Kisielewski (1980), 93.4% of all radon released from open-pit operations is released from the ore zone; thus, the calculations assumed that those surface areas were the main sources.

Jan 1, 1987

By Earle J. Klohn

INTRODUCTION The paper presents a broad overview of the geotechnical site studies required for siting uranium tailings dams. These studies, which are interdisciplinary in nature, touch upon such related fields as: hydrogeology, hydrology, and seismicity. Tailings dams are commonly used to develop tailings ponds for the storage of the waste products generated by mine milling operations. In the past, most tailings ponds have been developed either above ground on dry land, or in existing lakes. In the United States a majority of the uranium mines are located in arid or semi-arid regions and past practice has been to store the wastes above ground on dry land (1,2). Currently, the United States Nuclear Regulatory Commission (N.R.C.) recommends below ground disposal of uranium waste products, although they indicate that they will consider above ground alternatives (3). In Canada many of the existing uranium mines are located in a wet environment and past practice has been to use small lakes and depressions as tailings ponds (1,4). However, current practice in Canada leans towards above ground, dry-land storage (5,6,7), and the Atomic Energy Control Board (AECB) guidelines (5) indicate this to be the preferable method. In B.C., where a moratorium on uranium mining has been declared by the Provincial Government, there are no existing uranium tailings ponds. However, both the formerly proposed Birch Island and Blizzard uranium developments would have used dry land storage. Most of the existing non-uranium mill wastes in B.C. are stored behind tailings dams on dry land. The waste products delivered to the tailings pond comprise, the ground-up rock that remains after most of the uranium values have been removed and the excess chemicals used in the milling process. These waste products, which are called "tailings", are normally mixed with water to produce a slurry and then pumped to the tailings pond. Since the uranium recovered constitutes only a small percentage of the ore (usually less than 1%) (8), large quantities of waste rock and associated transportation water are discharged into the tailings impoundment area. Consequently, relatively large tailings pond areas are required for the uranium tailings. In recent years, major advances have been made in the design, construction, and operation of non-uranium tailings storage facilities (9,10,11,12,13,14, 15). These improvements have been based on combining the latest advances

Jan 1, 1980

By R. A. Pyper

Laboratory leaching experiments were conducted to ascertain the effectiveness of acidic solutions of thiourea, CS(NH2)2, for dissolving gold from finely disseminated gold ores. The ore tested was from the Chipmunk orebody of the Northumberland mining district in Nye County, Nevada, USA. Extractions of up to 90 percent were attained from the ore. Extraction was shown to be dependent on thiourea concentration, ferric sulfate oxidant concentration, acid concentration, and leaching time. Optimum conditions were an ambient temperature leach near pH 1.0 utilizing 100-200 kg/t thiourea and 50 kg/t ferric sulfate for 8 to 24 hours.

Jan 1, 1981

By Gary E. Geiger

laboratory studies were performed to assess the calcium carbonate inhibition performance of phsophonates and polymeric dispersants at high hardness and high pH conditions. Based on the results of these studies, a new calcium carbonate treatment program was developed that shows excellent Inhibition characteristics and Is not sensitive to calcium hardness.

Jan 1, 1998

By David M. Kjos

Large diameter autogenous and semi-autogenous grinding mills represent the primary thrust of the expanding grinding technology. In spite of initial difficulties, large autogenous and semi-autogenous mills have reached an acceptable level of technology which provides the mineral engineer with a reliable, low cost means of ore comminution. A successful milling installation begins during the design stage of the grinding mill and the plant it is to be installed in. This is particularly true in autogenous and semi-autogenous mills. Critical mill and plant design factors should be considered while the mill and installation are still only ?paper.? Various current liner designs will be discussed ranging from lifter bar/plate to integral types. Modes of operation such as "high-low" will be considered. Liner maintenance procedures ranging from laydown area in plant design, proper mill shutdown methods, to installation and bolt tightening complete the equation to yield optimum performance possible for any particular grinding application. The objective of this paper is to discuss trends in wear materials, designs and operating practices, and provide some guidelines for good practice as we move through the 1980's. We will put together concepts that relate to the designs, materials and applications so that higher performance can be obtained by the operator for his specific application. The concepts are shown as being in series because they are dependent on each other to achieve the desired performance.

Jan 1, 1985

By Alfred Weiss, Andrew E. Nevin, Thomas J. Neil, O&apos

As Edward E. Runyan, 1983 AIME President, in an interview excerpt in ME, June, p. 607, stated, "...the AIME Transition Committee has recom¬mended to the AIME Board that each Constituent Society be allowed the option of separate incorporation, whereby each could become its own separate legal entity." Background The American Institute of Mining Engineers (AIME) was formed in 1871 by 22 engineers in Wilkes-Barre, PA. Although originally a mining organization, it became a home for metallurgists, iron and steel industry people, and for the individuals in the expanding petroleum engineering profession. There are now four Constituent Societies: Society of Mining Engineers, located in Littleton, CO, 29,000 members; Society of Petroleum Engineers, located in Dallas, TX, 47,500 members; The Metallurgical Society, located in Warrendale, PA, 10,000 members; and Iron and Steel Society, located in Warrendale, PA, 6,500 members. Each of the four groups has grown and continues to serve the specific and/or diverse needs of its membership. As the needs and requirements of their industries and professions change, each of the Societies has perceived and initiated programs that serve their constituency rather than AIME as a whole. Therefore, each Society has recognized an increasing need for autonomy to better augment their own programs. An AIME Ad Hoc Transition Committee, with Robert Merrill, AIME Past President, as chairman, made a number of recommendations pertaining to AIME operations that were approved in October 1982 by the AIME Board of Directors. One of the recommendations was to endorse separate incorporation of the Constituent Societies on an individual-society-option basis. The AIME Board commissioned a task force of Constituent Society representatives to develop specific revisions to the AIME Certificate of Incorporation and the AIME Constitution and Bylaws. This was done to allow separate incorporation and to reflect the decentralized structure of the Institute. The SME-AIME Board of Directors subsequently approved the recommendation of SME Working Party #69 that SME pursue separate incorporation. Meanwhile, Working Party #69 continues to work with the other Constituent Societies and with the AIME Task Force on Reorganization to determine the form and substance of the separate incorporation. Why Incorporate? George Webster in The Law of Associations quoted Chief Justice Marshall's (1819) definition of corporation as: "A corporation is an artificial being, invisible, intangible, and existing only in contemplation of law. Being the mere creature of law, it possesses only those properties which the charter of its creation confers upon it, either expressly or as incidental to its very existence. These are such as are supposed best calculated to effect the object for which it was created." SME-AIME attorneys, Davis, Graham & Stubbs, have pointed out that the status of an organization operating as an unincorporated association is always unclear. At present, SME-AIME administers assets of almost $3.5 million (mainly property and inventory) but technical ownership and ability to enter into contractual relationships resides with AIME. However, the operation appears to outsiders (particularly those with whom SME-AIME does business) to be an independent operation which would be expected to be a legal entity in its own right. Advantages of Incorporation Liability. Because of legal ownership by AIME of all assets of the Constituent Societies, those assets are subject to the claims of any of the creditors of AIME or any of its constituent parts (i.e., the other societies). Liabilities can be those usually encountered in business but also encompass special risks, which could develop if there were a careless and erroneous publication of material that might be used in practice or if standards are improperly established. The recent US Supreme Court decision in American Society of Mechanical Engineers, Inc.,

Jan 10, 1983

By T. W. Meikle

Three nutrient amendments and a biological seed inoculant were evaluated for use in establishing vegetative cover on waste rock substrates. Randomized blocks were placed on three substrates. Treatments included two types of organic fertilizer, mineral fertilizer, Azospirillum bacterial inoculant, plus controls. The seed mix consisted of native grass species adapted to low nutrient conditions. Canopy cover has been monitored for three growing seasons. Results indicate: 1) two of three substrates support plant growth following amendment with organic fertilizers; 2) organic fertilizers increase cover substantially over mineral fertilizer; and 3) Azospirillum had no effect on canopy cover.

Jan 1, 1999