Search Documents

By Michael E. Mcllwain, Lee O. Nelson, Robert D. Rogers, James H. Wolfram

Examination of the economics and environmental consequences associated with phosphate fertilizer production documents the necessity for development of innovative production technologies. Evidence of phosphate ore's susceptibility to microbial alteration indicates that it will be an ideal candidate for industrial-scale bioseparation. There are at least two applications for the biosolu- bilization technology: (1) an industrial-scale bio- process similar to the presently used wet acid process and (2) production of small prills (bio- bead) containing unprocessed rock phosphate and the biological ingredients necessary to promote phosphate solubilization. At the present stage of development, the biobead technology is the preferred application. It is an energy-efficient "green" technology that will dramatically reduce the amount of solid waste and air emissions produced by the phosphate industry.

Jan 1, 1999

By C. M. Frost

Crude shale oil produced by gas combustion retorting of Green River oil shale was hydrocracked over a cobalt molybdate catalyst at operating pressures of 500, 1,000, 1,500, and 3,000 psig, an operating temperature of 8900 F, and a liquid hourly space velocity of 1.0. Hydrogen feed rate was maintained at 6,000 scf/bbl. The volume-percent yields of total liquid product were directly proportional to the operating pressure. Weight-percent conversion and volume-percent yields of gasoline were directly proportional to the log of the operating pressure. Catalyst deposit percentages were inversely proportional to the log of the operating pressure. Nitrogen and sulfur removal rates as well as saturation of the liquid products increased as the operating pressure was increased.

Jan 1, 1973

By Graham W. Gibbs

The current state of knowledge concerning mesothelioma risk estimates is reviewed. Estimates of the risk of mesothelioma exist for the commercial asbestos fiber types chrysotile, amosite and crocidolite. Data also exist on which to assess risks for winchite (sodic tremolite) and anthophyllite asbestos. Uncertainty in estimates is primarily related to limitations in measurements of exposure. Differences in the dimensions of the various fiber types and of the same fiber types at different stages of processing add a further complication. Nevertheless, in practical terms, crocidolite presents the highest asbestos related mesothelioma risk. The risk associated with sodic tremolite (winchite) appears to be similar. In chrysotile miners and millers, the mesothelioma risk has been linked with exposure to asbestiform tremolite. Exposure to chrysotile in a pure form seems likely to present a very low if any risk of mesothelioma. While the majority of mesothelial tumors result from exposure to the asbestos minerals, there are other well established and suspected etiological agents. While a practical threshold seems to exist for exposure to chrysotile, it is unlikely to exist for the amphibole asbestos minerals, especially for crocidolite. To date there is no indication of an increased risk of mesothelioma resulting from non-commercial fiber exposure in the taconite industry. © 2007 Elsevier Inc. All rights reserved. Keywords: Mesothelioma; Amosite; Grunerite; Taconite; Crocidolite; Tremolite; Anthophyllite; Winchite; Risk estimation; Etiology

Jan 1, 2007

By D. B. Haas

THE HYDRAULIC TRANSPORT of solids is becoming increasingly prevalent throughout the world. Major long-distance slurry pipelines currently in operation transport commodities such as coal and various ore concentrates distances of up to hundreds of miles. In the United States, a number of large-diameter, high-tonnage pipelines are under consideration for the transport of Western Plains coal to markets up to 1000 miles away. In these and other applications, the solids are generally quite fine, with 14 mesh being a typical limit of particle size for long-distance (over 100 miles) slurry transport. There are applications where it might be practical to transport solids consisting of larger particles distances of up t o 100 miles. Deposits of high-quality metallurgical coal are found in the inner foothills belt along the eastern edge of the Rocky Mountains on the Alberta-B. C. border. There are few existing railroad s and the possibilities of constructing extensions are limited because of environmental and economic factor s. In these circumstances, the most efficient transportation system might consist of a pipeline to transport the coal from the mine to beneficiation plants located near existing railroads 50 or 100 miles away. Such systems would minimize environmental effects, capital cost s and operating costs. To determine whether such a system would be technically feasible, experimental testing is needed to determine the energy requirements for transporting coarse coal in a pipe line. Currently, run-of-mine metallurgical coal is crushed to less than 1 1/2 inches before going to the beneficiation plant. In the proposed scheme, coal of this size would be transported through a pipeline to the beneficiation plant located at the railroad. The Transportation Development Agency and the Department of Supply and Services have awarded a contract to the Saskatchewan Research Council to study pipelining of coarse coal in pipelines ranging from 4 inches to 12 inches in diameter.

Jan 1, 1977

By D. D. Banerjee, S. K. Kawatra, T. C. Eisele

A high calcium fluid-bed combustor ash has been shown to be an effective binder at dosages of 1 to 2% of the magnetite concentrate weight. Magnetite pellets 1.3 cm (1/2 inch) in diameter were produced with dry crushing strengths greater than 22.3 Newtons/pellet (5.0 pounds force/pellet), which is comparable to the results produced using conventional bentonite binder. The effectiveness of fly-ash-based binders was considerably improved when calcium chloride was added as an accelerator. Addition of calcium chloride at a rate of 0.1 to 0.2% of the total powder weight increased the strength of dried pellets by as much as 22% compared to the strength of pellets made using fly-ash without accelerators.

Feb 24, 1997

By T D. Sullivan

Risk lies at the heart of all mining and nowhere more so than in pit slope design. Mining is principally about two areas of risk; safety and economics. This paper addresses the main elements of pit slope design and presents a view of the state of the art in terms of safety, design, prediction of performance, success and pit slope management. There has been a recent trend for serious injury and fatalities due to stability in open pit mines. The causes and contributing factors are analysed in relation to geotechnical knowledge, pit slope design and management. Currently there is no standard classification system for mine slope designs and it is considered doubtful if a universal system is possible. Designs are usually formulated in accordance with many different methodologies, various engineering principals and a number of different philosophical approaches, with results often presented in terms of Factors of Safety or Probabilities of Failure. However wide experience has demonstrated that even with apparently detailed engineering investigation and analysis at Feasibility Level, at the Operating Stage mine slope angles are regularly subject to large changes. The general experience is that these changes are ± 5° and 16° overall, which is considerably outside the accepted order of accuracy. For large deep mines these are huge changes and represent significant risks to the operations. The current state of practice in pit slope design is examined for two stages, feasibility and operating.

Jan 1, 2006

By Antonio A. Cristóvão, Alexandre Pinto

"Abstract Deep foundations of buildings using driven ductile iron micropiles TRIM solutions, leads to recognized advantages, from technical, schedule and economic points of view. High production rates together with the possibility of using conventional equipment, duly adapted, confer this solution a high versatility.The aim of this paper is to describe the main design criteria adopted for the foundations of the Church ""Nossa Senhora dos Navegantes"" building in Lisbon - Portugal. In addition, results of a full scale load test carried out at site are presented, confirming the adequacy of the solution to the geological and geotechnical scenario, which is characterized by the proximity of the Tagus River Basin as well as the presence of heterogeneous landfill material and alluvial layers of soft clay (muds).1. INTRODUCTION Located on the right bank of the Tagus River, in Lisbon, the new Church building of ""Nossa Senhora dos Navegantes"", patroness of fisherman and navigators, with three or four upper floors, is surrounded by a school and by new residential buildings.The Tagus River basin is known by its alluvial soft soils, achieving, in certain areas, more than 50m meters depth, challenging the construction of new facilities due to the significant unfavorable geotechnical conditions.With a modern an unusual architecture, allusive to the ships used by the Portuguese navigators, the building has a reinforced concrete structure, with one basement and three upper floors. A bell tower with about 40m high, emerging from the structure, marks the landscape with the presence of this religious building (figure 2).For all the reasons previously described, geotechnical engineers play a crucial role on the design of valid foundation solutions, from both technical and economic point of view. Ideally, the solutions adopted should be supported by full scale load tests, performed at site, so that design assumptions could be verified and adjusted on time."

Jan 1, 2014

The sphere of operations of dry crushing has been so much enlarged of late years that the following notes with reference to its advantages and limitations, and also some practical results in connection with the crushing of gold ores will probably be of service to the members of the Institute. Until recently, with one notable exception that of the Mt. Morgan Gold Mine, dry crushing has only been practiced to a very limited extent in Australasia, and elsewhere it might be said to belong to industries other than mining Its sphere of usefulness depends on the fact that the' product is delivered in a dry state without the separation of the finer particles from the coarser to any appreciable extent, thus enabling the following advantages to be achieved with different ores.

By W. G. Kegel

The past few years have produced a rash of demands for changes in America's way of doing things. From manufacturer to consumer, the rules have been changed. Some of the demands were needed and, when legislated to requirements, did manage some good for all concerned. Other demands made by zealots and taken up by regulatory agencies have forced costly changes on our way of life. No segment of industry has been exposed to more new rules and regulations than the deep coal mining industry in the United States. There is no denying that some good has evolved, but most mining men know that the effects have done more to reduce production and increase cost than they were ever intended to do.

Jan 1, 1975

By E. G. Valdez

Laboratory research demonstrated that ceramic wall and floor tile can be produced from electric furnace phosphorus slags composed of calcium silicates. Grinding the slag in a pebble mill, followed by magnetic removal of deleterious magnetite, produced a raw material that could be compounded and formed into wall tile by dry pressing, sintering, and glazing. The effects of process variables such as forming pressure and sintering temperature were investigated. Wall tile bodies produced by this method were comparable to commercial tile. The tiles were readily glazed to a smooth shiny finish and met ASTM Specifications C34-62 for structural clay load-bearing tile. The estimated cost of producing wall tile by this method compared favorably with the retail market value for similar wall tile. Addition of borax or other additives to the ground slag followed by dry pressing and firing likewise produced a commercial grade of floor tile.

Jan 1, 1974

By S. Vorberg, J. Preussner, B. Fischer, U. Glatzel, R. Völkl, M. Wenderoth

Pt-Al-X alloys have shown good mechanical properties and adequate oxidation resistance. Starting from a promising Pt-Al-Cr alloy, the influence of Ni additions was investigated. After ageing finely dispersed precipitates are observed. Nb, Ta, Ti and Re increase strength when added as partial substitute for Al. Minor additions of B increase creep resistance and rupture time remarkably, owing to strengthening of the grain boundaries. The evolution of the alloy development programme as well as selected properties of the multi-component Pt-base alloys are presented.

Jan 1, 2006

By Rob Stewart

Acknowledgements ? Josef Macek(Manitoba Geological Services) ? Sally Goodman (SRK) ? Inco Geologists ? Rogerio Montiero ? Thompson Mine Geologists Introduction ? Regional Geology ? Thompson Geology ? Stratigraphy ? Sulphide Characteristics ? Conceptual Model ? Structural History ? Belt ? Thompson Mine ? 1D Deposit ? Ore Controlling Structures ? Using Structural Data to Guide Exploration ? Summary

May 1, 2006

By J. D. Miller, C. L. Lin

Appropriate software and hardware necessary to adapt a x-ray CT analyzer for determination of coal washability has recently been developed and sucessfully tested for well characterized samples under laboratory conditions. Evaluation of the CT-based analyzer under simulated on-line conditions is also presented to verify the on-line capabilities of the newly developed x-ray CT analyzer for the control of coarse coal cleaning circuits. The investigation shows that the data obtained from CT washability analyses compare favorably with experimental sink-float data. Further, image frequency was considered to evaluate the CT-Based coal washability analyzer for simulated on-line conditions. Specifically the number of observations (image spacing) needed for accurate sampling and the total time required to perform the calculations for a representative data set were determined.

Jan 1, 2001

By William Gleason

"Once the primary fuel source for the United States and the economic backbone for communities from Appalachia to Wyoming, coal has been on a steady decline since the mid 1990s, and is now at the center of political debate in the United States.The political spectrum of the United States is divided on the future of coal and its place in the energy sector. The coal mining industry and the communities that rely on coal have increasingly been pitted against forces that wish to regulate coal to the history books.In 2008, President Obama launched what many have called his war on coal, and during his eight years in office, he pushed through numerous pieces of regulations and legislation and that he said were aimed at reducing carbon emissions, but that others viewed as direct assaults on the domestic coal industry. Obama led the United States delegation to Paris to sign the Paris Accord in 2016, a 196-country agreement pledging that the United States would do its part to reduce carbon emissions. His administration also instituted clean air, power and water regulations that added extra environmental burdens to many industries, but perhaps none more so than the coal industry.In this month’s lead feature, “A study of U.S. coal mine closures since 1994” (page 18), the impact of the war on coal, and other factors, can be seen in text and figures. Author Jacob Brinkman and coauthors Jay Schafler and Catherine Johnson scoured the data of the U.S. Energy Information Administration (EIA) and the U.S. Mine Safety and Health Administration (MSHA) to show how coal production and mines have been impacted since 1994 and how the years 1994 to 2000 and 2008 to 2016 were particularly hard on the industry.For example, in 1994 there were 2,354 coal mines in the United States. Currently, there are 1,035 mines in operation.In 2016, then candidate Donald Trump promised to end the war on coal and to put coal miners back to work. In 2017, President Trump has followed up on those promises. He announced plans to withdraw the United States from the Paris Accord, signed an executive order designed to undo the Clean Power Plan put in place by President Obama, halted the research on the health effects of mountaintop removal coal mining, directed the U.S. Environmental Protection Agency (EPA) to revise the guidelines of waste water from power plants and has touted that more than 1,000 coal miners have returned to work since he was elected."

Jan 9, 2017

The Raub Gold Mines are situated approximately in the centre of the Malayan Peninsula in the State of Penang. Part of the area, now known as "Raubhole," was opencut some 800 years ago by the Mon Khmers, a Cambodian people, whose vestiges mark numerous outcrops in South Eastern Asia. With their decline and extinction the work was abondoned, leaving a large pond in a dense thicket of Beluka (secondary growth).From the year 1885 onwards the history of Raubhole and the water therein records a chain sale starting from an enterprising local "Rajah," who had "assumed" authority, to an equally wakeful Singapore Arab; thence through the agency of a "down-and-out" beachcomber to a hopeful Australian company in the "goldbrick" days. Subsequent catastrophe on a depleted stringer was followed by reconstruction; the deserved reward of a long mining life, and an output of nearly 800,000 ounces of gold. Owing to the loss of notes and data stored in Singapore, this paper is not as complete as it should be, especially in respect to its metallurgical phases. Apologies are therefore tendered in advance for any deficiencies which may be noted.The necessary regional geological data have been taken largely from the admirable investigation of the Raub area by J. A. Richardson, A.R.C.S., B.Sc., F.G.S., of the Malayan Geological Survey*, and, throughout the paper, months represent lunar periods of 28 days and money is expressed in sterling.MINING SECTIONSAs shown hereunder the reef system has been divided by nature into seven isolated sections, which have been of necessity worked as seven separate small mines. From north to south these are:-(a) Sungei Agas consisting of very shallow workings to the south of, and adjacent to, a granite-porphyry mass known as Bukit (hill) Kajang. This area has not been worked for many years.(b) Bukit Malaka which is also shallow.(c) Bukit Jalis.(d) Bukit Koman which, with (c) and (e), consitutes the main workings and which has possibly been determined in depth.(e) Anderson Section.(I) Raubhole Section.(g) The workings under Raub Village.

Jan 1, 1945

By C. H. Keplinger

WARTIME factors have strengthened the production engineering consciousness of the petroleum industry. The basic principles of sound oil-production technology have been accepted as the standard by the industry and the governmental co-ordinating agencies. Every effort is being made to furnish larger quantities of petroleum with a minimum expenditure of materials and under strict conservation practices. The sphere of influence of production engineering extends from fundamental reservoir control of withdrawal rates and reservoir pressures to bolstering production from stripper wells. Serious transportation difficulties in moving oil to the East Coast have stimulated secondary recovery operations in the Appalachian and East Central oil-producing states. Diminishing discovery of new oil reserves by exploration activities increases the importance of promoting efficient oil-producing methods and practices throughout all productive areas in the United Nations.

Jan 1, 1943

By Jim Johnson

The purpose of this paper is to summarize and discuss a variety of site specific conditions which are typically evaluated as part of the engineering design process for heap leach pads, solution control ponds, and associated facilities. The following sections will focus primarily on the topographic, climatologic, hydrologic, and geotechnical evaluations critical to selection of heap leach sites, and selection of a preferred heap leach configuration or method. Other important considerations in the design of a heap leach project, including evaluation of ore properties and leachability, pregnant solution processing requirements, spent ore neutralization/disposal requirements, and other anticipated reclamation requirements are beyond the scope of this paper are not addressed in any detail.

Jan 1, 1998

By E. A. Cleveland

A glance at the map discloses the fact that the Pacific Great Eastern railway either traverses or crosses some of the most important rivers of the province: the Squamish with its branches the Stawamus, Mamquam and Cheakamus; and the Green, Lillooet, Birkenhead, Fraser and Quesnel rivers. Each of these and some of their tributary streams, having their ?sources and upper reaches in the higher altitudes in regions of abundant snowfall, is capable in greater or less degree of furnishing water under suitable heads for the economic production of power. Beginning at its present terminus at Squamish the railway has the only hydro-electric development within its territory among the whole list of streams mentioned. A 225 horsepower installation at the edge of the East branch of the Squamish river, using water from Stawamus river, a branch of the former, under a head of 418 feet, is a modest beginning. Two or three additional sites, where water may be used under somewhat similar heads, may be found on this little stream. Next above Squamish, along the route of the railway, is the Mamquam, a long tributary of the Squamish from the eastern slopes. It has a drainage area of something like 130 square miles with widely varying discharges of from less than 50 to about 14,000 cubic feet per second. The preliminary investigations so far have disclosed no suitable storage sites, so the Mamquam may be regarded as a small continuous power stream - probably less than 1000 horsepower.

Jan 1, 1925

By W. T. Irvine

"The Britannia ore deposits are approximately 20 miles north of Vancouver; and occur in a prominent ridge facing Howe sound. A large ironstained bluff first attracted the serious attention of early prospectors. This; upon investigation; proved to be the outcrop of a large copper orebody. The highest outcrops were 4; 300 feet above sea-level.The original discovery was made in 1888, but no real development took place until 1902. The first mining was done in what came to be known as the Jane orebody, and some production was obtained from this in 1905. Underground exploration led to the discovery of several other orebodies. The first main adit, the 1,050-foot level, was driven to tap the ore at an elevation of 3,300 feet above sea-level. During succeeding years, however, long adits were driven from points lower down on the mountain side. These, with connecting shafts, followed the ore to horizons well below sea-level. The lowest working has now reached to 880 feet below sea-level. The property has been in almost continuous operation since its original exploitation in 1905. Until the end of 1944, 732,414,420 pounds of copper and 261,125 ounces of gold had been produced from the mine."

Jan 1, 1954

Ravensthorpe Nickel Operation (RNO) is a major new mine and processing plant currently being constructed by BHP Billiton in a ?green field? site near the small town of Ravensthorpe, about 150 km west of Esperance and six hours drive from Perth in Western Australia. Ensuring that the project has a positive overall impact on the surrounding region and that this extends well beyond the life of the operation will be a major challenge for RNO, state and local government, and the local community. For the last two years, the Centre for Social Responsibility in Mining (CSRM) has been assisting RNO management and the RNO Community Liaison Committee to develop a community sustainability monitoring framework for the project. This paper reports on the process that was used to develop the framework, describes the main elements and briefly discusses key learnings from the exercise.

Jan 1, 2007