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By R. R. Oder

Reported are weight, particle size, gross chemistry and magnetism measurements for lithic, mineral and fused soil components separated from five lunar soils using dry, open-gradient, magnetic separation. Pure diamagnetic anorthite, a feedstock for the electrochemical separation of oxygen and metals, has been separated from anorthistic highland soils. In addition, paramagnetic ilmenite has been separated from high-titanium, basaltic mare soils. Ilmenite, a feedstock for oxygen preparation by hydrogen reduction, may also serve as a source of He3 for use in fusion power generation. Agglutinates (vesicular, glassy components containing metallic iron) have been separated from all of the soils. Iron and refractories can be used for space construction. Metallic iron is easily detected in lunar soils by magnetic susceptibility measurements. Based on the exploratory laboratory results, conceptualizations of innovative magnets for processing lunar soils are presented.

Jan 1, 1993

By T. A. Vivian

The use of heavy media organic solvents to recover coal from its attendant gangue is hardly new. DuPont built a pilot plant using pentachloroethane in 1936 at Weston Coal Company, Weston Breaker, Shenandoah, Pennsylvania. That's almost half a century ago. Since that time, it has become common practice to utilize similar classes of chemicals in laboratory separations of coal samples. It is the objective of this paper to discuss some specific separations on both pilot and laboratory scale on samples representing different classifications of coal. These separations have been carried out on coarse (+4 M), middling (4 x 20 M), and fine (-20 M) coal samples. The coal samples tested include Pennsylvania anthracite; Pennsylvania, Indiana and Colorado bituminous; Wyoming sub-bituminous; and Texas lignite. Other chlorinated solvents were used to vary the specific gravity of separation.

Jan 1, 1984

By W. P. Blacutt

A financial-economic model incorporating physical, market and policy variables has been developed for mining investment in Bolivia. Additional risk criteria emanating from political instability, new mining legislation, recent environmental regulations and a new minerals taxation system are accounted for and are integrated into the investment decision model. Results of the model indicate that geologic and market variables have the dominant effect on the investment-worth function. Among policy variables, exchange rate and taxation policies have the most significant influence. Depreciation allowance for infrastructure development has negligible weight in the investment-worth function. The business structure of the firm considering investing in the Bolivian Polymetallic Project, is found to be an instrumental factor in the investment-worth outcome.

Jan 1, 1995

By Harold E. Goetzman, Blair R. Benner

The U.S. iron ore industry is located primarily in Northern Minnesota and Michigan's Upper Peninsula with one additional small plant in Missouri. There are currently some 10 plants operating that produce about 48 million tons per year of pellets. The major reagent use occurs in the three general areas of: flocculation, flotation and pellet additives. Minor areas of usage are for corrosion inhibition and dust suppression. Current practice as to types of reagents, consumption, and method of application are reviewed. The interaction of reagents with other parts of the process are discussed. Also included is a discussion of future reagent needs.

Jan 1, 1994

By Thomas P. Goslin

T e mechanization of industry to reduce labor costs and to improve product quality is affecting he scale industry as it has affected many other industries. With increased emphasis on higher production rates many operators are experiencing difficulty in overcoming production problems where weight is a factor. Unfortunately, the scale industry has not shown the development over the last twenty-five years that other instrument industries have. For centuries the balance scale has been the standard and the workhorse of most weighing operations. In recent years considerable effort has been applied to designs to make balance scales more acceptable to industries employing automatic or semi-automatic processes. For the most part the designers have not attempted to replace the basic scale but toautomate functions of material handling and human judgement. Modern dump scales, for example, will accept material from a conveyor until a preset amount of material is on the scale, At this time the scale turns off the conveyor, dumps the load of material and repeats the operation with any desired timing. These improvements have helped industry. Even the scale observer has been replaced with devices which observe the scale reading and operate on weighed objects according to their weights. In spite of' the application of automation to the material handling, the balance scale has not been completely satisfactory. One reason for this is fairly evident when one considers the construction of the scales. Inherently, they are slow devices because of the inertia of the beams. The beam scale, primarily a static measuring device, is at the best limited to slow dynamic measurements.

Jan 1, 1958

By Stephen P. E. Redmond

A 15 km water supply tunnel is being constructed in Buenos Aires, Argentinata expand the capacity of the existing system. Two 4.3 meter diameter Earth Pressure Balance (EPB) tunneling machines operating at times from the same shaft on a congested work site and advancing through sedimentary deposits underlying this wonderful city pose interesting challenges. As of January 1999approximately 50% of the tunnel has been excavated. Combined machine production rates of 1026 m/month have been achieved. Presentations made in prior proceedings can be referenced for details of the overall Project scope and for details of the tendering process. The purpose of this paper is to compliment those presentations by addressing now the execution of the work.

Jan 1, 1999

By David Whitehead

My qualification to speak on the globalization of the the mining industry comes from having worked in the industry in Europe, North and South America, Africa and Australasia in positions ranging from exploration geologist to chief executive. For about a third of my career I have lived and worked in the Southern Hemisphere. And for much of the rest of my career I have been involved in or responsible for activities in the Southern Hemisphere. This has given me the opportunity to experience globalization from the sharp end, as it were. This means speaking English with an Australian accent, Spanish with a Chilean accent, French with a West African accent and Dutch with an English accent. My topic is globalization, especially of the mining industry from a Southern Hemisphere perspective and specifically the experience and history of Gencor in that context. First, I will say a little about what globalization means to the southern part of the world: How and why the South differs from the North and how the challenge of globalization affects a south-based company differently than a northern one. I will also detail how Gencor has made significant progress in globalizing through the acquisition of mining assets from Shell. As Fig. 1 shows, I have divided up the world into northern and southern components, rather than hemispheres. The southern world comprises mainly countries that have emerged from the status of economic - if not political - colonies of nations such as England, Spain, Portugal, France, the Netherlands and, surprisingly, Italy and Germany. I have not considered the Indochinese and Arabian peninsulas in my southern world. The emergence of the. former is still in its early stages while the latter is clearly a part of the northern economic system. Large parts of Africa and South America are geometrically in the Northern Hemisphere but economically in the southern world. The reverse is the case for the IndoPersian peninsula. With the distinguished exception of Australia and South Africa, most of these countries nationalized their mining industries and mineral patrimony after attaining political independence. A major element of the globalization of the mining industry is related to the privatization of the mining industry in these countries and to the opening up of their min¬eral patrimony to non-national exploitation. The Southern Hemisphere is the watery part of the world. It is almost three quarters ocean as against a slight preponderance of land in the north. Economically, ocean areas have only a fraction of the productivity of land, except in a few oil-rich areas like the Gulf of Mexico and the North Sea. The consequence is that even on an economically level playing field we would expect the south to generate only about one third of the world's economic product.

Jan 1, 1997

By Robin J. Batterham, Stephen H. Algie

It is often stated that innovation is central to the economic survival of mining and mineral processing in the face of global competition, and yet technology is often far from a core strategy in our industry - hence the concerns that are often voiced about the apparent slow rate at which new technology is applied. Much of the discussion stems from a lack of understanding of the role of technology in innovation, and of the role of R&D within the innovation process. To a large extent this has all been said, however, the messages are clear and deserve repetition. This paper expresses the personal views of the authors, based on experience in government-funded (CSIRO and universities) research, and in CRA Ltd, a large mining and mineral processing company. Further than this, it explains how our own development unit within the CRA Group has come to see its key roles as including the transfer of technology, and the training of technologists to move into the operating business units. We conclude that these critical tasks are the keys to creating the environment that will allow us to maximise the contribution of technology.

Jan 1, 1995

By R. Robertson

Dense medium cyclones are the preferred means for cleaning 112 in. x 14 Mesh to 28 Mesh (12.7 mm x 1.0 mm to 0.6 mm) raw coal and are becoming a common choice for cleaning raw coal from a nominal top size of 2-1/2 in. to 3 in. (63.5 mm to 76.2 mm) down to 14 Mesh to 28 Mesh (1.0 mm to 0.6 mm). During the last ten years, dense medium cyclone circuitry design has undergone changes which have combined to improve process efficiency. This paper describes these improvements and compares present day design with the design used prior to the mid 1980's. Improvements in the following areas are described: Raw coal desliming, cyclone configuration, drain and rinse applications, dilute medium circuitry, and instrumentation and control.

Jan 1, 1997

By D. M. Range

Exxon is reclaiming an 80 hectare (200 acre) Wyoming uranium tailings basin (10 Mt) in accordance with U.S. Nuclear Regulatory Commission requirements. The reclamation plan is designed to control the tailings and their radioactive emissions for at least 1000 years. Rigorous modeling and analyses of potential erosion by wind and water were used in planning. The use of riprap was minimized and the need for long term reclamation maintenance was eliminated. The resulting design is similar to erosionally stable regions created by nature. The concepts used in the design and implantation have wider reclamation application.

Jan 1, 1989

By M. J. Rex, K. L. Wiley, D. S. Ramey

In situ leaching, initiated in 1986 at the San Manuel Mine, was economically developed in 1989. The primary reason for this lag time between startup and viable production was the time required for technical development. The technical development pursued comprised detailed design, development and implementation of in situ well construction methods, formulation of suitable well pattern arrays and the development of extensive hydrogeologic and geochemical knowledge of the mineral deposit. Since 1989, the in situ leaching program has become a viable and cost-effective method to extract copper from the supergene mineralized zone of the San Manuel deposit. The in situ leaching methods that are currently used have been progressively expanded and continually developed. They will become the cornerstone of copper production from the San Manuel oxide mineral deposit. This paper presents an overview of the supergene hydrogeology, current design techniques, drilling methods and well completion, pump determination and setting, solution management and future plans for the increased extraction of copper by in situ leaching methods at the San Manuel Mine.

Jan 1, 1995

By R. D. Hamilton, W. J. Miles

In 1987, the International Agency for Research on Cancer designated crystalline silica as a 2A probable carcinogen. As a result, crystalline silica is regulated under the Hazard Communication Standard as a probable carcinogen at a concentration of 0.1% or greater in the workplace. Crystalline silica will be listed as "reasonably anticipated to be a carcinogen" by the National Toxicological Program. This designation of crystalline silica as a probable carcinogen has created major issues for the mineral and chemical producer, including labeling, hazard communications, marketing a material with potential hazard exposure, and potential liability. The State of California also regulates crystalline silica under Proposition 65 in products as a carcinogen, based upon the IARC determination that it is a probable carcinogen. More federal and state regulations are anticipated as a result of the IARC classification of crystalline silica and its subsequent federal regulation. Respirable crystalline silica has been regulated as a hazardous dust for many years by OSHA. This regulation was initiated to prevent silicosis, another occupational disease. OSHA has established monitoring devices for determining the concentration of airborne respirable silica in order to measure exposure to this substance. The accurate determination of the crystalline silica content is critical to dealing with these health risks and regulations. In the past, crystalline silica was considered to be safe and, because of its ubiquitous nature, little effort was made to determine or quantify its presence in most materials. The Hazard Communication Standard requires that a1l products containing 0.1% or greater crystalline silica must be properly labeled for this material and its hazard. Unfortunately, the 0.1% threshold was not chosen on the basis of established analytical capabilities for crystalline silica, but results from general limits for potentially carcinogenic chemicals and substances. Numerous methods have been developed for the determination of crystalline silica in a variety of products. However, these methods are not generally applicable since they must be specific for silica in any of its crystalline states and not just for total silica content. Chemical tests for silica are not difficult and quite accurate at the 0.1% level; however, in addition to its crystalline phases, it occurs in amorphous phases and in a wide variety of crystalline and amorphous silicates. In general, there is little correlation between total silica content and crystalline silica.

Jan 1, 1991

By Warfield Garson

Few, if any, of the non-ionizing radiation health hazards to be found in either surface or underground coal mining are uniquely different because of their being found in the work environment. Hence, they can be considered generally for their bio-effects on the worker when found in the mining work environment. The same may not be said, however, for the lack of non-ionizing radiation and its bio-effects, particularly as it relates to underground coal mining. The term "non-ionizing radiation" refers to various forms of electromagnetic radiation of wavelengths longer than those of ionizing radiation. As the wavelength gets longer the energy of electromagnetic radiation decreases. Therefore, all non-ionizing forms of radiation have less energy than cosmic, gamma, and X-radiation. In order of increasing wavelength, non-ionizing radiation includes ultraviolet, visible light, infrared, microwave, and radiofrequency radiations. The energy frequency and wavelength range of both the ionizing and non-ionizing electromagnetic forces are shown in Table I. To convert the wavelengths of various radiations to Ångström units, one multiplies millimicrons by ten. In a vacuum, all electromagnetic radiation has the same velocity, namely 3 x 1010 centimeters per second. The natural source of radiant energy here on earth is our sun which emits radiation continuously over a wide spectrum. This radiation on average reaching earth ranges from 290 nm in the ultraviolet range to over 2,000 nm in the infrared range with a maximum intensity of about 480 nm in the visual range. You will note this falls into the visible blue wavelength and accounts for our blue sky and blue ocean and deep water effects. We are all familiar with the fact that the passage of solar radiation through the atmosphere to the earth changes the spectrum considerably because the atmosphere absorbs and scatters many of the sun's rays. The ozone in the upper atmosphere absorbs the shorter ultraviolet wavelengths and water vapor absorbs some of the infrared wavelengths. Smoke, dust particles, gas molecules and water droplets scatter the rays, especially those of shorter wavelengths. In addition to the sun, every gas, liquid or solid object at a temperature above absolute 0° radiates energy. Solid objects emit almost continuous spectra. At low temperatures only radiation of the longer wavelengths in the infrared range is emitted, but as the temperature of the object is increased, more and more of the shorter wavelengths are added. This fact is most readily demonstrated by heating a piece of steel. When a piece of steel reaches a temperature of about 1,700° Fahrenheit, it gives off radiation at the red end of the visible spectrum and appears dull red. As the temperature is further increased, the shorter rays are also emitted, until at about 2,100°F, the metal appears white, due to the emission of wavelengths throughout the entire visible range. Gasses, on the other hand, when heated emit radiant energy only at certain wavelengths, which are characteristic of their chemical structure. This latter fact is of importance in underground coal mining as high intensity gas and vapor lamps are becoming more and more utilized for illumination in underground coal mining. The biologic effect of non-ionizing radiation exposure depends upon the type and duration of exposure and on the amount of absorption by the miner. The effects of this radiant energy on the miner fall into four distinct types: (1) the heating effect of infrared radiation, (2) the effect on the eye of visible radiation, (3) the effects of ultraviolet radiation, and (4) the growing potential effects of the misuse of microwave radiation. Each non-ionizing type of radiation will be considered individually. ULTRAVIOLET RADIATION The sun is the major source of ultraviolet radiation, which is of concern in open pit and surface mining at certain seasons and in certain climes necessitating protection for the surface miners under those conditions; nonetheless, there are some man-made sources such as electric arc lights, welding arcs, plasma jets, and special ultraviolet bulbs for illumination underground that demand surveillance in the underground environment to be aware of whether the miners are at risk above the threshold limit values allowable. Since ultraviolet radiation has little penetrating power, the organs that are affected are the skin and the eyes. Ultraviolet radiation is strongly absorbed by nucleic acids and proteins, and the effects in man are largely chemical rather than thermal. Short-term effects on miners include acute changes in the skin. These are of four types: (a) darkening of pigment, (b) erythema (sunburn), (c) increase in pigmentation (tanning) and (d) changes in cell growth. Ultraviolet radiation also causes acute effects on the tissues of the eye. Overexposure can lead to keratitis, inflammation of the cornea, and conjunctivitis. Long-term effects of ultraviolet exposure include an increase in the rate of ageing of the skin with degeneration of skin tissue and a decrease in elasticity. Late effects of ultraviolet on the eye include the development of cataracts. The most serious chronic effect of ultraviolet exposure is skin cancer. Ultraviolet radiation effects are increased by some industrial materials and drugs. After exposure to such compounds as cresols, the skin is exceptionally sensitive to ultraviolet radiation. Photosensitivity reactions occur after exposure to a variety of other chemicals and drugs including dyes, phenothiazines, sulfonamides, and sulfanylureas. On the other hand, we must remember that ultraviolet radiation has an important role in the prevention of rickets. Vitamin D is produced by the action of

Jan 1, 1981

By Zhang Dekuan, Wang Haifeng, Yi Weiping, Wan Liping, Yu Yunzhen

The fundamentals of domain knowledge, knowledge base building, system structure, principle of inference mechanism, function of explanation mechanism, application analysis on Expert System of In-situ Leaching of Uranium (ESILU) are described, especially the Dempster/Shafer theory on inexact reasoning, which was used in ESILU, is detailed discussed. The application of in-situ leaching for abstraction of uranium and the analysis of parameters required for evaluation of uranium deposit. the procedure of evaluation of uranium dewsit for the purpose of in-situ leaching as well as the concept related were introduced. For building knowledge base, discussion is emphasized on production rule, which wasused in ESILU, on representation of rules and facts and application as well. From the system menu provided in the paper, the readers will, in a certain content, under- stand the functions of system structure and the way to set up. Several paragraphs are written concentrated on the procedure of backward reasoning and the principle of inference mechanisms combined with knowledge bases. Tracing interpretation and acquisition of knowledge with interactive method, which the system flexibility is considerably strengthened, are the main specific features of ESILU.

Jan 1, 1996

By N. S. Tanious

The accuracy of vibrating wire stress meters has been questioned by various users in the mining industry. During an in situ coal pillar study, a laboratory evaluation program was developed to determine whether stress meters could produce reliable measurements in coal. More than $0 stress meters were tested for accuracy, repeatability, effects of setting pressure, and the concept of using a single curve for interpreting the stress-meter data. The testing medium was lucite, a material with a modulus of elasticity very similar to coal. The evaluation demonstrated that the stress meters did provide repeatable measurements, but that accuracy was lacking when the recommended interpretation technique was used. Therefore, a new technique was developed that required all stress meters to be calibrated in the laboratory before use in the field. This new technique reduced the average error to typically less than 10% and, in the worst case, to below 15%.

Jan 1, 1988

By Richard Jr. Ray, Richard Druesedow

The Virginia Operations of Consolidation Coal Co. include a diversity of mine fan configurations which have been tested to quantify pressure losses through the inlet ductwork. Airflow and pressure measurements were taken at four shaft sites to calculate losses for the 90-degree bend at the top of the shaft and the self-closing dampers or closing doors located between the shaft and fan. Velocity contours were then developed from the test data to determine flow patterns in each fan system component. In addition, yaw and pitch angles of airflow through the fan annulus were measured to evaluate turbulence levels created by various inlet ductwork designs. The test results indicate that proper design of the shaft collar and ductwork arrangement for main mine fans can substantially reduce system pressure losses and air turbulence. BY minimizing the pressure drop experienced on the surface, these design improvements enable the bulk of the total pressure developed by the fan(s) to be utilized in the mine.

Jan 1, 1995

By Jan A. Nemcik

Steel mesh has been used successfully for many years to control friable roof conditions and prevent loose roof and rib material from caving into the roadway. Despite its extensive use, the installation of steel mesh is difficult to automate and many other products have been evaluated as an alternative for skin control. Ideally, the properties of these new products should be similar or better than those of the steel mesh. In particular, development of a strong and resistant shell that minimizes movement along the fractured rock and coal surfaces between the bolt anchors is recommended. A strong surface adhesion and the strength of a reinforced polymer skin can provide the necessary toughening mechanism required to enhance roadway surface support by forming a reinforced polymer/rock surface layer. Most of the Thin Spray-on Liners (TSL) evaluated in the mines are weak with slow curing times, and the plastic mesh currently used to support the coal ribs is relatively weak. Therefore, neither material can seriously compete with steel mesh. Currently, a new polymer product that cures in seconds and forms an instantaneous strata binder that surpasses the properties of steel mesh is under development at the University of Wollongong.

Jan 1, 2009

By M. B. Mirza, W. A. Sadik, B. T. Stanley

This paper presents the ventilation design for an underground testing facility in a salt medium. The under-ground workings consist of two 3.6 m-diam (12 ft-diam) watertight shafts and about 1830 m (6000 ft) of drifting. These facilities are designed to provide access for an in situ testing of a salt horizon in which a variety of hazardous and nonhazardous materials could be temporarily stored or permanently deposited. The ventilation system includes a design basis for gassy mine conditions and provides for the option of bulk air cooling and heating.

Jan 1, 1987

By V. Svalbonas

Presently the U.S. mining industry is very conscious of costs. It is timely, therefore, to review the dominant specifications used in the industry for procuring large size-reduction equipment. These are compared with other specifications and procurement methods, such as ASME and DOD, using the criteria of resulting costs, safety/ quality, and fitness-for-service.

Jan 1, 1987

By G. C. Adams, J. H. Fowler

Canada's gypsum industry began more than 200 years ago in the Maritime provinces when farmers attempted to supplement their incomes by selling "land plaster" to traders bound for the United States. Rising from such humble beginnings, gypsum now contributes significantly to the economies of nine of Canada's 10 provinces. Thirteen open-pit and three underground mines produced a total of 8.4 Mt (9.3 million st) of crude gypsum, and 17 processing plants manufactured 2.5 Mt (2.8 million st) of finished products in 1985. Recent economic growth in North America has resulted in steady increases in gypsum production. However, competition from foreign producers and by-product gypsum pose a growing threat to Canada's gypsum mining industry.

Jan 1, 1987