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By S. O. Moshier, L. S. Barron, J. C. Hower

The Hardgrove grindability test, commonly used in coal characterization, was conducted on 13 Mississippian carbonates from Kentucky, Tennessee and Illinois. The results demonstrated that the grindability increases with a decrease in the Si02/(MgCO3+CaCO3) ratio, with fine-grained and petrographically-complex stones having lower grindabilities. Also, the relationship between the Bond work index and Hardgrove grindability is significant.

Jan 1, 1993

By W. S. Fyfe, G. Southam, T. J. Beveridge

Sporosarcina ureae was able to grow in the presence of tip to 10-ppm L-asparagine complexed gold. However, 10 ppm Au3+ was found to be highly toxic to Sporosarcina ureae, killing 109 bacteria/mL within a few seconds. To compare the effects of these responses on gold mobility, an in vitro bacterial biofilm model was developed to examine the interaction be¬tween Sporosarcina ureae and ionic gold or L-asparagine gold complexes in gravity fed columns. The immobilization of ionic gold was between 80% and 90% over a period of one week. But, as the available cellular reactive sites became saturated, immobilization decreased to 14% within two weeks. In the L¬asparagine-gold system, gold immobilization in the cytoplasm occurred at a high rate (80% to 90%) throughout the experi¬ment, with limited toxicity towards Sporosarcina ureae. The bacterial immobilization and detoxification of L-asparagine¬complexed ionic gold was associated with a low molecular weight, i.e, <5,000 dalton (atomic mass unit), intracellular protein fraction. This peptide-complexed gold would allow for the continued biogeochemical cycling of gold under ambient (<100°C) surface or near-surface conditions.

Jan 1, 2000

By Steve Van Kouteren

Filters and absorbents purify, clarify, and clean many types of liquids by removing solid particles. In addition, absorbents provide a convenient way to handle liquids and to clean up liquid wastes or spills. Filtration or absorptive processes are accomplished either in a mechanical way, as in absorption and filtration, or in a chemical way, as in adsorption. In filtration, minerals and rocks used as filter mediums are extensively utilized in applications requiring the filtration of high volumes of liquids. End use applications include liquid food products, waste waters, petroleum and chemicals, and drugs and pharmaceuticals. Upon closer examination of all of the materials used as filters and absorbents, industrial minerals and rocks represent only a small proportion of the total amount, as shown in [Fig. 1] (Rees, 1991). Given all the industries that use these minerals, most of the volume is concentrated in a few major end-use markets. Within these major end-use markets, a handful of minerals account for most of the total volume and value. The focus for this chapter will be to discuss the industrial minerals and rocks used as filters and absorbents in the most important markets. The selection of the minerals and markets to review is solely based on the total volume of material used and in special cases, those where the value of the market and material is high. The major materials include diatomite, perlite, sand, gravel, and such specialty clays as montmorillonite and attapulgite. These materials are mainly used for the filtration of food, chemical, and petroleum products. In addition, they are used as absorbents for pet litter and oil and grease spills, and as carriers for pesticides and fertilizers.

Jan 1, 1994

By William H. Pomroy, Annie M. Carigiet

This U.S. Bureau of Mines report is an analysis of underground coal mine fire incidents occurring in the United States during the 15 years from 1978 through 1992. The fire data used in this analysis were obtained from Federal Mine Safety and Health Administration (MSHA) mine fire investigation reports. Fires were analyzed by year, state, coal bed thickness, mining method, evacuation measures taken, ignition source, burning substance, location, equipment involved, detection method, time of day, number of injuries and fatalities, and method of extinguishment. In all, 164 fires are reported, or an average of 10.8fires per year. The most common ignition source was electricity, the most common burning substance was coal, the most frequent fire location was the belt entry, belt conveyors were the most common equipment involved in fires, and water was the most common extinguishing agent.

Jan 1, 1995

By Robert L. Randall

The mineral industries have a continuing need for market forecasting and analysis for a variety of purposes, among which are organization and control of the sales effort, financial and corporate planning, and evaluation of the anticipated revenue from investment in proposed projects. For anything beyond the simplest extrapolation, some kind of economic reasoning or analysis is called for, which may or may not be incorporated into a formal or quantitative model. The principles described here apply to most of the commercially significant minerals and metals. The examples are drawn largely from the copper market, as it is the one with which I have the most practical experience. Practical forecasting is the process of analysis and synthesis from three categories of knowledge: facts and statistics, theory, and practical knowledge and informed opinion. Although many attempts have been made to build forecasts on only one of these three pillars, none has been successful as an operating procedure because of the lack of balance. There are no facts about the future-only about the present and the past. Facts can illuminate the future, but the future can be described only in terms of probability or more or less likely states of affairs-not as a continuous extension of the past and present. Likewise, theory, although useful as an organizing discipline and for providing a methodology of analysis, is inadequate for the complexities of reality. This is especially so when there is feedback between plans and forecasts to produce a new outcome and when there are significant elements of unpredictable free will, such as presidential jawboning or foreign policy considerations. Such elements are difficult to accommodate in neat theories, although they must certainly be reflected in the forecasts. Pure opinion frequently suffers from both a lack of-disciplined reasoning and the presence of biases or self-interest. While the future is unknown, it tends to cast its shadow before it; hence, forecasting is the art and science of positioning oneself so that the shadow becomes visible to the forecaster.

Jan 1, 1979

By Carol A. Hill

Native sulfur occurs with barite, celestite, and bioepigenetic calcite in the Culberson, Pokorny , and Leonard Minerals deposits, Delaware basin. The sulfur in these deposits, in "castile" masses, and in deposits of the Fort S tockton district have 6 34s values between +9 and -15. Native sulfur in the caves of the Guadalupe Mountains is somewhat lighter [(634s = -15 to -25)]. Barite in the Culberson, Leonard Minerals, and Comanche Creek sulfur deposits have 63% values of +35 to +73; celestite in the Culberson and Leonard Minerals occurrences have values of +38 and +36, respectively, and 87Sr/86Sr values of 0.707808 and 0.708138, respectively. Barite associated with sulfide, deposits, Guadalupe Mountains, have [634s] values of +41 to +62. Barite at Seven aeart Gap, Apache Mountains, is somewhat less enriched in heavy sulfur [(634s = +14 to +37)].

Jan 1, 1992

By D. J. Lachel, Douglas E. Hansen, Bruce Kennedy

The very high cost of exploration and development for new mines requires that a carefully planned, complete, and technically competent geotechnical evaluation be applied to the ore body and the surrounding rock. The ground conditions must be predetermined sufficiently so that, during the development and exploitation stages, unexpected conditions will be of minor consequence. Ground conditions are a major factor affecting the cost of excavated items such as shafts and inclines. For example, shafts cost less to sink in tight dry ground than in highly pervious ground below the water table, with all other factors being equal. The proper mining methods also is dependent upon the ground conditions. Bad ground for room-and-pillar mining may be ideal for caving methods; whereas, ideal ground for room-and-pillar mining would be extremely difficult for a caving operation. To do a proper engineering design, the parameters of strength, deformability, and permeability must be determined, in addition to the loads that will be applied as a result of the mining activity. The required degree of accuracy for each parameter depends upon the individual case. For example, the strength of massive rock in which openings of small cross-sectional area are to be driven at shallow depths needs to be resolved only within several thousand kilopascals (pounds per square inch). Under such conditions, the rock strength is not likely to be of great economic importance unless the rock is very weak. Large openings at great depths require a much more accurate appraisal of rock strength and deformation characteristics. Ground water conditions are important at any depth. Today, a number of techniques exist for evaluating conditions before opening up the ground for development. These techniques and their applications are described in more detail later in this text. The evaluation of ore body ground conditions should start at an early stage, as soon as the deposit has been proven viable for a mine. Economic geology investigations mainly serve to define the value and limits of the ore deposit. To do this properly, the geology of the site is determined in at least as much detail as is necessary to define the "controls" for the ore body. The ground-condition evaluation must determine the engineering properties of the ore body and the surrounding material. This includes the structural geology as it relates to rock strength; i.e., the frequency, extent, and orientation of discontinuities such as faults, joints, bedding, etc. Ground water conditions also must be determined. It is important that the detailed geology of the site be determined at an early date. Reasonable geotechnical parameters must be established during this time period, so they can be used in mining model studies that include both physical and mathematical models. The ultimate goal bf-the geotechnical evaluation is to predict the ground behavior as the excavations are made and how the ground behavior will affect the safety and economic well-being of the mine. The formulation of a ground-condition evaluation program should be planned carefully to determine the particular geotechnical parameters only in as great a detail as will have a bearing on the mine design. For instance, it is not necessary to make numerous triaxial tests in strong rock when the mining will be conducted within a few meters (feet) of the surface in a regime of gravity loading and an absence of tectonic stresses. Similarly, it is not necessary to invest large amounts of time and effort in the determination of joint strengths if the orientations of the joints are such that the failure could not occur along them. Generally, the determination of ore body ground conditions can be divided into four main steps: 1) The general and structural geology of the site must be determined; this is determined primarily during the economic evaluation. 2) The material behavior characteristics of the deposit and the vicinity must be determined. 3) The ground water hydrology of the deposit and the vicinity must be determined. 4) Miscellaneous ground support considerations must be established. Gross features are defined first, followed by a series of increasingly detailed investigations. Specifically, the geology study should start by utilizing techniques such as remote sensing, topographic map interpretation, geologic mapping, etc. After the gross features, such as major faults, have been delineated, the studies are directed toward defining the more detailed elements of jointing, rock strength, ground water hydrology, and other characteristics. This information is used to formulate an assessment of the strength of the ore body and the surrounding rock. Finally, all of the gathered information is integrated to make an assessment of the rock behavior in relation to the types of openings, the excavation methods, the support requirements, etc., that should be used for the rock conditions that are present. The mine design and the geotechnical assessment should be an iterative process. General conclusions about the rock conditions will dictate a type of mine plan. The specific mine plan then should be modified by specific geotechnical considerations. For example, an initial assessment may conclude that the ore body is strong and that a strong rock unit is present over the ore body. Thus, one definite possibility is to mine the deposit by room-and-pillar methods. However, subsequent investigations may reveal faults through the deposit, requiring relocation of the mine openings so that pillars and other structures are in sound rock. In other words, the final mine plan should be compatible with the geotechnical aspects of the ore body.

Jan 1, 1982

By James P. Dorian

In 1990, the former Soviet Union ranked first worldwide in the production of asbestos, chromium, iron ore, iron and steel, lime, manganese, mercury, nickel, peat, potash, and titanium. Since the middle of this century, that nation had maintained one of the world&apos;s most valuable mineral industries, ranking number two in 1950 and number one in 1990. It is clearly an enormous mining industry, with more than 1300 enterprises and an estimated employment base of 1.2 million persons (Table 1). Despite its size and historical achievements, however, the mining industry of the 1990s in the former Soviet republics is encountering problems in performance, efficiency, transportation and utilization. The industry operates below full capacity and is plagued by outdated technology and equipment, rising production costs, capital shortages and labor strikes, in addition to general economic deterioration and civil unrest. Attempts to boost domestic minerals supply in the republics so far have failed because of economic difficulties. And the republics lack the financing required to initiate new, large-scale development projects.

Jan 1, 1992

By R. Trottier, B. H. Kaye

Characterizing the structure of such open-structured dusts such as diesel soot and those present in welding fumes plus any other dusts which were initially formed by precipitation or agglomoration of subsidiary units in a flame process has always been a difficult task. Recently, scientists have been able to use the concepts of fractal geometry to model the growth of diesel soot and fume fine particles and characterize their structure using fractal dimensions. The measured fractal dimension of a diesel exhaust at various levels of scrutiny can be used to study the health hazards posed by the soot. Thus, the fractal dimensions of the overall structure can be related to the dynamics of the dust both empirically and theoretically. In this communication, the use of fractal dimensions to describe the structure of smoke and fine particles which pose a respirable hazard are reviewed. Experimental studies linking the measured fractal dimensions of the fine particles to dynamics of the fine particles in respirators and in the lung are outlined.

Jan 1, 1987

By Dennis Molvik, Omar Fulton, Chris D. Breeds, Don Gonzales

The Tolt Pipeline No. 2, West Snoqualmie Valley project, is part of a water supply project linking the Tolt reservoir in East King County to the City of Seattle through a nominal 2.13 m (7-ft) inside diameter conveyance. Receipt of the National, 2002Microtunnel Award provided recognition of the many challenges overcome by this project. Baseline conditions revealed in the Geotechnical Documentation included over-consolidated glacial deposits, landslide and alluvial deposits, artesian water, boulders up to 36-in in diameter, logs, heaving sands, and liquefiable soils beneath the river. Schedule constraints associated with setting the shafts in the floodplain of a salmon bearing river and the fickle performance of the river during those times it was not supposed to flood added to the challenge.

Jan 1, 2003

By John C. Edwards, Robert C. Bates

Results are given of a mathematical study by Bureau of Mines personnel of overpressurization ventilation effects in underground uranium mines. The mathematics and computer codes make it possible to analyze many facets of transient and steady-state radon diffusion with Darcy flow. Rapid changes in radon flux occur after imposing a pressure differential across the model. Flux into the model mine drops to near zero and then increases to the steady-state level, while the sink flux increases rapidly and then drops slightly to the steady-state level. Magnitudes of mine flux decreases and sink flux increases are dependent upon the distance from the mine to sink, permeability, and amount of overpressure. Current work on more complex models is also described.

Jan 1, 1981

By Ian J. Corrans, Gary Johnson, John E. Angove

Activox® is a hydrometallurgical process used to oxidise sulphide concentrates. The process is based on two relatively simple, established unit operations; i.e. fine or ultra-fine milling (UFM) and pressure oxidation under mild conditions. An under-standing of, and ability to control the pulp chemistry during oxidation has resulted in the successful Activox® treatment ( on a batch scale) of a wide variety of sulphide flotation concentrates; • pyrite/arsenopyrite + gold • pyrite/chalcopyrite + gold • pyrite/chalcocite + gold • pyrite/enargite/tetrahedrite + gold Oxidation rates are rapid (1-2 hours retention time) and gold

Jan 1, 1995

By D. A. Dahlstrom

Energy costs have had a serious impact on all basic industries today. This is due to the significant amount of energy that is used to convert natural resources into usable products. Other factors such as transportation with its major energy requirement and materials employed in processing that have already required significant energy input for their manufacture accordingly influence delivered cost to the user. The farmer is a good example of this. While his large capital investment for land, machines, and buildings is highly impacted by today&apos;s interest rates, his chemical fertilizer, herbicides, and pesticides as well as those same machines and transportation costs for his products have also been seriously affected by energy costs. With the many unit operations involved in mining and mineral processing, several of which require significant inputs of energy, one can only conclude that this industry has experienced a great increase in percentage of total cost for energy alone. Fuerstenau (1975) indicated that the minerals industry used about 12.5% of the total energy produced in the US. McNulty (1983) listed the total energy requirements for the production of 0.9 t (1 st) of various metals including the energy consumed in the manufacture of supplies employed, such as tires, explosives, chemicals, grinding media, etc. (Table 1).

Jan 1, 1987

By H. Hejny

The objective of the project is to construct and operate a pan-European underground drainage and minewater management research centre, which would be the hub for data gathering and dissemination in real time of new data to users for analysis and interpretation, as well as serving as a model for consistency, for other centres at key water management sites throughout Europe which would feed data in real time through the hub. The data from the centre will be essential for informing River Basin Management Plans arising from the EU Water Framework Directive, which is an important driver for the project. The implementation of this Directive sets out a requirement for all Member States to develop River Basin Management Plans for all water resource systems. The facility would be a major contribution to sustainable water management in Europe.

Jan 1, 2007

By R. N. Chakravorty, R. J. Kolada

Explosions of methane in coal silos and coal ships is an ever present hazard. Recent investigations have shown beyond question that considerable accumulations of methane do occur in coal storage silos and numerous recent explosions in coal transport shipping strongly indicates that the same conditions also exist in ship storage holds. Investigations have shown that the main concentrations of methane occur within the actual coal pile. Within this region normal silo and ship ventilation systems are ineffective. The main 1ine of defence is therefore to exclude potential sources of ignition or to place the coal in an inert atmosphere, or both. This paper presents the results of a methane survey of all operating silos in Western Canada. These results demonstrate that a serious and widespread hazard of explosion exists. This paper also discusses various methods by which this hazard may be reduced including methods of venti1ation, inertization, microbiological control and early warning systems.

Jan 1, 1987

By L. Alan Weakly

Page one is missing from book

Jan 1, 1982

By D. S. Holmes

Biological processes for metal solubilization and ore beneficiation are in widespread use today. There are also some promising new applications of biotechnology in the areas of metal concentration and toxic metal cleanup. Recent progress in genetic engineering promises both to revolutionize the existing biological process and to expedite the adoption of the new biological applications. But before it can do so effectively, progress must be made in many areas of fundamental research and in biochemical engineering. These issues are addressed with special reference to the biotechnology of semi-enclosed containers (bioreactors), dumps, heaps, in situ and under- ground leaching, and with respect to the biotechnology of metal concentration. Finally, certain biological considerations for bacterial strain improvement are discussed.

Jan 1, 1987

By A. C. Lyons, A. J. Reed

INTRODUCTION A trend which is obvious in the United Kingdom and is thought to be evident in other parts of the Western world is the disproportionate rise in the cost of tunnel mining labour compared with other tunnel cost increases. This disproportionate increase in labour costs has been accompanied by, and may be the result of, a shortage of skilled working labour. To combat this problem there has been a steady increase in the use of machines for excavation and for the erection of tunnel linings to keep the amount of skilled labour working below ground to a minimum. The typical tunnelling cycle, where the ground needs continuous support can be excavation, temporary support, temporary lining, grouting and permanent lining. It is obviously an advantage to combine as many of these operations as possible and carry out as much as possible by machine. Machines have been developed which will, either alone or used in combination with a shield, excavate and, when necessary, temporarily support the excavation. If a segmental lining is used, it can be so designed that it will form the permanent lining and reduce the cycle time and skilled labour requirement to a minimum. In cases in which the ground can be cut accurately to a smooth profile and will stand without support for a sufficient time, the lining can be expanded against the ground and the necessity of grouting eliminated. In cases in which ground will not stand without support, the usual method is to use a bolted lining and to grout behind it preferably as the shield is shoved forward. Whichever technique is used (this is largely determined by the ground) it is an advantage to make the segments as large

Jan 1, 1974

By Keith Kern, Joseph P. Matoney, Kenneth E. Harrison

INTRODUCTION "When there is an economic need for cleaning fine coal to low ash, the technical difficulties will be solved. The utilization of fines below 28 mesh will determine the degree to which beneficiation will be carried. Whenever these "fines" will be processed into smokeless fuels or used as new materials for the chemical industry or for hydrogenation, a higher degree of cleaning will be economically justified”.(l) This quote from the 1943 edition of Coal Preparation correctly anticipates the use of fines as "smokeless" fuel or as a future component of boiler fuel and a1 so as a raw material for the chemical industry or possible new uses such as for internal combustion engines. Fines utilization depends upon an economic need and possibly neglects to say an environmental need or a government funded development program as the prime mover for development. In any event, this conference is faced with the "need" to beneficiate fine coal and undoubtedly among the processes that will be discussed are the unit processes of future coal preparation facilities. HISTORY OF DEVELOPMENT It is interesting to look at where we have been, where we are now and where we possibly will be in the future. In order to put some limitations on this presentation, we will for the most part confine our remarks to this century and particularly developments since World War II. We also will limit our remarks to the preparation of bituminous coals in the United States, and for the most part, to wet processes. In the 1943 edition of Coal Preparation, clues to the processes being used to beneficiate coal are contained in the Chapter Titles. An extensive treatment of "Hand Picking" was contained in Chapter 8. Chapter 7 contained a description of methods for "Preparation at the Face". Chapter 18 dealt with "Slurries, Sludges, Slimes and Water Treatment" and defined this size of coal as being the size at which "Jigs and Chance Cones are usually dispensed with and other methods such as the hydrator, tables, and froth flotation are employed. Generally the limit is 1.7mm to 3.4mm. In the days before World War I1 the then modern bituminous coal preparation plant contained jigs or Chance Cones for the coarse material +6.35mm, concentrating tables, launders or some classifier type of coal washer for the fines (6.35 x 0.15mm), and froth flotation as the only method of cleaning minus 0.15mm coal which was used very sparingly.

Jan 1, 1988

By Pamela J. Nebgen

Surface mine planning and watershed management requires the manipulation of a massive volume of data. The processes of collecting, examining, selecting, and generalizing information for the production of maps and sediment structure designs are a major part of mine planning and evaluation. Computer aided design graphics systems are becoming increasingly more important to the surface mining industry. This paper illustrates the applications of a digitizer and plotter interfaced to an IBM PC-XT microcomputer, which form the hardware elements in the new University of Kentucky hydrology, sedimentology, and structure design package called SEDCAD.

Jan 1, 1986