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By Robert F. Kehrman

As part of the Bureau of Mines research on the In-Situ Uranium Leaching, various geophysical resistivity measuring techniques were -evaluated to identify a rapid reliable method for detecting the underground migration of lixiviant outside of the planned limits. Surface and downhole galvanic resistivity and controlled source audio-magnetotelluric (AMT) methods were tested at an in-situ uranium mine in Northern Wyoming during start-up of a new mining area. Downhole galvanic and AMT were the most promising techniques.

Jan 1, 1980

By Lawrence E. Mannion

In southwest Wyoming lies buried the world's largest source of natural sodium carbonate, or soda ash. Perhaps a hundred billion tons of trona (sodium sesquicarbonate) are contained in ancient lake beds in the Green River basin'). There the Green River Formation encloses more than 40 extensive beds of trona. At least 25 of these exceed 3 feet (1 meter) in thickness and most of them are more than 300 square miles in extent. Five have been exposed in mines and lie between 800 and 1500 feet below the surface. Others lie at depths of from 400 to 3500 feet. Three companies have underground mines that supply trona to adjacent soda ash plants. These are the FMC Corporation, Allied Chemical Corporation, and Stauffer Chemical Company. A fourth, Texasgulf Corporation, has a mine under development. In 1974, annual soda ash capacity in the Green River area was approximately 4,300,000 tons, which requires the mining of about 7,500,000 tons of trona.

Jan 1, 1975

With commodity prices rising again and market conditions stabilizing, the Metals Economics Group (MEG) found that most mining companies increased their exploration budgets in 2010. In the groups 21st edition of the Corporate Exploration Strategies (CES), MEG found a 44-percent rise in the estimated worldwide exploration total for 2010. MEG found that the estimated total 2010 budget for nonferrous metals exploration reached $12.1 billion, reinstating almost two-thirds of the industry?s $6 billion in cuts to exploration in 2009. Nonferrous exploration refers to expenditures related to precious and base metals, diamonds, uranium and some industrial minerals; it excludes iron ore, aluminum, coal, and oil and gas. In 2008, exploration budgets were at an all-time high of $14.4 billion. This capped a six-year run in which budgets rose. In 2009, nonferrous exploration budgets dropped 42 percent in 2009 as the global economic crisis and declining prices for almost all commodities took their toll on the industry. Metals prices - the primary driver of exploration spending - have improved markedly since bottoming in early 2009, and have traded well above their long-term trends throughout 2010. In response, major, intermediate and junior companies have all increased their aggregate exploration allocations in 2010. In particular, the significant improvement in the availability of equity financings for the juniors over the past 12 to 18 months has allowed this group to account for the largest share of the overall increase in exploration spending this year.

Jan 1, 2011

By S. K. Kawatra

Three International Symposiums-the 14th International Minerals Processing Congress, the 17th APCOM, and the SME-AIME Fall Meeting special symposium on Design and Installation of Com¬minution Circuits-held in 1982 contained a number of papers relating to the fundamentals of processing coals and metallic minerals. In addition, many papers were published elsewhere in the literature. Some of the more significant papers are discussed below. Flavel reviewed key performance parameters, such as energy-size relationships for crushing processes and presented a fundamental basis for optimizing crusher productivity and possibly for development of improved crushers. Pascoe et al. reviewed the use of such control schemes. Magerowski and Karra presented a paper on a computer program developed to and in the design of crushing circuits. The problems associated with the scale-up to very large ball mills were discussed by Arbiter and Harris, and by Kavetsky and Whiten. Both groups concluded that limits on mill productivity arise due to problems associated with particle breakage and transport through mills. Austin et al., and Herbst and Rajamini reviewed the state of the art for the use of grinding circuit simulators for design and control. The effects of mill operating and design parameters on selection and breakage were discussed in detail. The philosophy of control and instrumentation for grinding circuits was extensively discussed by Kawatra and Seitz. Their paper presented for the first time an analytical basis for the inferential particle sizing technique and provided a fundamental basis for the implementation of this technique. The effect of reagent addition variation's on the performance of coal flotation circuits was reported by Kawatra and Waters, and on sulfide flotation circuits by Klimpel et al. Both groups analyzed circuit behavior from a kinetic point of view and reached similar conclusions on the effects of collectors and frothers. The computer simulation of an iron ore flotation circuit also was reported by Kawatra et al. In this work particular attention was paid to the phenomena of froth overloading. Klimpel et al., Kawatra and Waters, and Niemi et al. discussed the philosophy of control by flotation circuits from a fundamental kinetic point of view. An extension of the use of high intensity magnetic separators to the beneficiation of specular hematite was discussed by Thayer and Linkson.

Jan 5, 1983

By Louis W. Cope

In the early 1900s, vat leaching was a common process for treating gold ores. It was, however, labor intensive and was abandoned in the 1930s. Technology advances in recent years, though, have caused vat leaching to once again become a viable alternative in precious metal processing. At least three plants have been built. Others are being considered as alternatives to agitation and heap leaching. What is vat leaching? Vat leaching is a process in which ore is crushed and screened to a size of between 6 to 12 mm ( 0.25 to 0.5 in.) This crushed ore is placed in a large, boxlike container where an alkaline-cyanide solution is added and later removed. The process might be likened to indoor, controlled heap leaching. The ore does not require fine grinding in a ball mill. Therefore, capital and operating costs are lower than agitation treatment. But the extra handling causes costs to be slightly higher than heap leaching. If any amount of fines is present, the ore should be agglomerated.

Jan 1, 1991

By P. J. Macbeth, R. F. Overmyer, K. K. Nielson

INTRODUCTION Over the past several years, Ford, Bacon & Davis Utah Inc. (FB&DU) has been involved in research, development, and engineering activities concerning uranium mill tailings; specifically of interest in this paper are efforts in radon gas exhalation and surface flux attenuation measurements, environmental influences on radon fluxes, and basic research into radon gas behavior. Our projects have included measurements of effectiveness of specific cover material in attenuating radon surface fluxes from mill tailings, characterization of the parameters in cover materials and tailings that influence radon exhalation, long-term tailings stabilization planning, determination of the effects of moisture on radon emanation and diffusion from ores, and determinations of baseline radon fluxes. Our efforts have been sponsored by U.S. Department of Energy, the U.S. Nuclear Regulatory Commission, Tennessee Valley Authority, the commercial uranium industry, and we are presently engaged in efforts for the U.S. Bureau of Mines. Much of the material presented in this paper is taken from our published reports on radon flux attenuation and tailings stabilization (Macbeth et al., 1978; Nielson et al., 1980; Rogers et_ al., 1980; Thamer et al al., 1980). CHARACTERIZATION OF RADON GAS EXHALATION One dimensional diffusion theory based on Fick's laws is the basis for the modeling of radon gas migration through large quantities of porous tailings and cover materials applied over the large areas of tailings piles. Fick's first law relates the gaseous concentration gradients to the flux over the entire surface and defines the effective diffusion coefficient De as: [ ]

Jan 1, 1980

By Brett P. Spigarelli

"To meet the growing need for CO2 capture and storage technology, Michigan Technological University is studying CO2 capture using alkali-based solvents. The objective of the present study was to find a way to increase the absorption rate of CO2 into an alkali solution without reducing the absorption capacity of the solution. One approach to increasing absorption rate is to use a surfactant to chemically alter the gas bubble size. The surfactant chosen for the study was a neutral-charge polypropylene glycol methyl ether (PPGME) with a molecular weight of 200. Experiments were conducted to study the absorption rate of CO2 at varying surfactant concentrations. Results showed that as the concentration of PPGME increased in solution, the absorption rate also increased. The CO2 absorption rate increased from 3.45 x 10-3 mol/min CO2 at 0g/L PPGME to 3.92 x 10-3 mol/min CO2 at 0.48 g/L PPGME. This amounted to a 14% increase in the CO2 absorption rate with no decrease in the absorption capacity of the solution. IntroductionChemical absorption using an amine solvent is currently the most mature carbon capture and storage technology available. Amines are advantageous in that they have a fast CO2 absorption rate, which leads to a high CO2 removal efficiency. However, amine absorption has some considerable drawbacks, such as high energy requirements, high equipment corrosion rates, amine degradation in the presence of oxygen, high waste generation and a large increase in plant footprint if new equipment is constructed (Herzog and Golomb, 2004; D’Alessandro et al., 2010). Due to these drawbacks, Michigan Technological University (MTU) is studying CO2 absorption using alkali-based solvents, which address the above disadvantages of amine solvents."

Jan 1, 2015

By James W. Cooksley

This report concerns a seismic geophysical exploration program which was conducted 3 miles southeast of the Carlin Mine, in Lander County, about 18 miles north of Carlin, Nevada. A twelve-fold reflection seismic line was executed over a one-mile traverse in section 32, Township 35 North, Range 51 East. This study is part of an exploration pro- gram directed toward finding Carlin-type gold deposits which are concealed under younger alluvium and volcanics. The exploration objectives of this program are as follows: 1) measure the thickness of the younger, sedimentary and volcanic deposits which overlie the "productive rock sequence", 2) delineate the Roberts Mountains thrust fault, 3) investigate the origin of the geochemical anomalies present in the western portion of section 32.

Jan 1, 1985

By J. E. Hoffman, T. J. Keefe, Michael E. Stout, O&apos

M.A. Industries, Inc. has developed and is now offering on a commercially available basis, complete systems to recover and recycle lead from spent SLI batteries. The system begins with the breaking and separation of the component parts of the batteries and subsequent treatment of the effluent water produced by this operation. The recyclable materials recovered from this process are metallic lead, lead paste and polypropylene. The lead paste is introduced into a process to convert it from a lead sulfate to a lead carbonate. The process also regenerates the salt solutions into reusable carbonate. The lead carbonate is then leached into an acid bath where it is later recovered by a proprietary electrolytic process. The metallic lead is recovered in a short rotary furnace producing metal for further refining and alloying. The polypropylene is further washed and then introduced to a reclaim extruder along with the proper modifiers and additives. The resulting resin can then be sold on the open market to injection molding processors. This complete system greatly reduces the amount of waste to be disposed of and completely complies with all applicable EPA guidelines.

Jan 1, 1993

By Charles E. Melbye

INTRODUCTION In a discussion of South American exploration, it is difficult to know how much area to cover, as there has been such intense exploration for many years in all of the South American countries. Therefore, I have decided to discuss only Argentina, Bolivia and Peru in this paper, since I am most familiar with these three countries. This familiarity has been gained during my last 12 years of nearly continual exploration and mine development. Furthermore, these three countries form a contiguous block straddling the Andes Mountain chain for 2,200 miles in length N-S. Although Chile is part of this block, I excluded that country because it has had the longest recent history in South American exploration, and it is now in a mature stage where new important mines are being placed in production every year. Exploration must progress a lot for the other three countries to attain the stature of Chile. However, major exploration successes such as Yavacocha and Pieriva in Peru, Kori Khollu in Bolivia and Bajo Alumbrera, Agua Rica and Cerro Vanguardia in Argentina certainly indicates that these countries are rapidly accelerating in exploration successes and the resulting new mine developments. Also, by concentrating on three countries, I have avoided making this paper too lengthy. This paper will cover activities of both junior and senior mining companies, both of whom are making significant contributions to exploration. The junior companies often make the initial discovery, develop it further and then bring in a major company when large capital is required. Since most exploration is for gold and copper or combinations of these, most descriptions will cover these types. However, there are significant new exploration successes for zinc and for silver-lead-zinc, and they will be covered, as well. After descriptions of the various properties, there is included a discussion of the governmental policies of Argentina, Bolivia and Peru, as to how they are affecting exploration activities and budgets. Some of these problems could have a major negative affect on the future exploration plans of many companies. I have intended to cover what I think are significant exploration developments in each country, and if a company project is omitted, there was no intention to slight anyone. Since exploration results change monthly, there could be

Jan 1, 1998

By A. Shakoor, A. M. Hirt

The compressive strength of coal, and its variation within and between seams, was determined for four Pennsylvania coal seams (Pittsburgh, Sewickley, Upper Kittanning and Lower Kittanning). Large coal blocks were obtained from 12 coal mines (three mines per seam) and cut into 50-mm (2-in.) cubes using a low-speed saw. The cubes were tested for compressive strength, with the results used to compute actual pillar strength. Using the tributary area approach, the pillar stress was determined. The pillar stress and strength data were used to calculate the factor of safety against pillar crushing for each mine. The cube strength was also correlated with various physical and chemical coal properties (density, percent absorption, percent ash, percent sulfur and percent carbon) to see if any strong relationships exist. The coal's mean compressive strength varies from 9.1 MPa (1326 psi) in the Lower Kittanning seam to 37.8 MPa (5480 psi) in the Pittsburgh seam. Between different seams the pillar strength varies from 29.5 MPa to 48.1 MPa (4282 psi - 6981 psi). Although coal strength appears to be weakly related to carbon content, no relationship was found between compressive strength and other physical or chemical properties. Since the values for the safety factor against pillar crushing generally exceed the recommended value of two, the existing pillars are mostly overdesigned. This implies that an accurate assessment of coal compressive strength could result in the use of smaller pillars and, thus, increased coal production.

Jan 1, 1993

By W. F. Hahnert, P. A. S. Ralston

In off-line training of a rule-based controller, the significant measure of successful training is the quality of control provided by the generated rule set. In an adaptive or on-line control environment, performance is also measured by the ability to accurately maintain a satisfactory rule set, but within constraints on speed and/or resource availability. Very small population genetic algorithms, or microGAs, have been proposed as a means of capitalizing on the hill climbing characteristics of faster local optimization techniques while requiring less memory and retaining much of the robustness of traditional, larger population genetic search. A traditional genetic algorithm and a similar microGA are developed and applied to two control problems. The performance of these algorithms is analyzed with respect to (1) the quality of the rules learned, (2) the rate at which learning occurs, and (3) the memory resources required during learning.

Jan 1, 1993

By C. J. Pritchard, R. D. Jacksha, K. V. Raj, C. B. Sunderman

In underground metal/nonmetal mines, repeated localized short-term exposure to high levels of airborne contaminants can become a serious health issue. Currently, there are no common mechanisms to control or mitigate these short-term high exposures to contaminants. To improve miners’ health and safety, the U.S. National Institute for Occupational Safety and Health’s Spokane Mining Research Division (SMRD) is developing a smart monitoring and control (SMAC) system for the real-time monitoring of mine air quality, with integrated countermeasures to reduce high concentrations of airborne contaminants in localized sections of mines. To develop and test a SMAC system capable of being implemented in an underground mine, SMRD researchers built a test apparatus incorporating a fan, louver, ducting and sensors combined with atmospheric monitoring and control software. This system will institute effective countermeasures to reduce contaminant levels, improving miner safety and health.

Jan 1, 2018

By Catherine T. Aimone

A computerized cost model has been developed to simulate the technical and economic effects of strip mine blasting in the vicinity of structures. Current surface mining regulations restrict the allowable level of production blasting as a function of this distance. Blast design modifications,' therefore must be employed when blasting in the vicinity of homes to ensure compliance with federal and state regulations specifying limits to the seismic effects generated from a blast. The blasting level allowed. is computed by the charge weight of explosives per delay from the following scaled distance formula: [ ] where W is the charge weight per delay, in kilograms (pounds), D is the distance factor corresponding to the regulatory limit of peak particle velocity to which a structure may be subjected to. Current regulations specify 2.54 cm (1.0 in.) per second corresponding to a SD factor of 27 (60) (Federal Register, 1977).

Jan 1, 1982

By Stanley R. Riggs

The rocks exposed in the phosphate district are of Neogene age and consist of clayey quartz and phosphorite sands overlying phosphatic dolomite. The Bone Valley Formation is redefined as a marine phosphorite containing primary phosphorite and abundant terrigenous sediments. It contains a Middle Miocene vertebrate and invertebrate fauna and conformably overlies the Hawthorn Formation containing similar invertebrate fauna. A new, unnamed formation, with Pliocene and Pleistocene fauna and containing reworked phosphorite, overlies the Bone Valley disconformably. Its phosphorite is derived from the subjacent Bone Valley by post-Middle Miocene erosion and deposition in stream channels and marginal marine environments. The Bone Valley contains two main types of primary marine phosphorite. Orthocbemical phosphorite, a direct precipitate of microcrystalline phosphorite (microsphorite), occurs as a cement or binder in thin beds. Allochemical phosphorite consists of clastic phosphorite particles that were originally formed as microsphorite on another part of the shelf. Microsphorite was deposited in a very shallow open marine environment which had an abnormally high phosphorous content caused by upwelling currents. The mechanism of deposition is still in doubt, but organisms probably were a major factor. Soon after deposition, microsphorite was indurated, periodically torn up, and the resulting fragments transported and deposited elsewhere on the shelf. These processes account for a great portion of the clastic phosphorite in the Miocene deposits of Florida. The primary fossil skeletal material is of minor importance.

Jan 1, 1965

By Mary C. Jennings, Peter F. Marcus

This paper examines the dynamics of aluminum consumption (all products), scrap recovery and primary aluminum capacity for the Western World through 1995, with particular emphasis on the U.S. aluminum industry. The relationship between the prices of ingot, sheet and extruded products is also explored.

Jan 1, 1986

By John T. Cumberlidge

The Groveland deposit, in the Upper Peninsula of Michigan, consists of an E -W trending overturned syncline of Middle Precambrian Vulcan iron formation. At Groveland, the Vulcan formation can be divided into four units or facies. The total succession may be more than 550 feet thick, and consists of a basal unit composed of a lean chemical quartzite with traces of magnetite; a non-banded, partly clastic unit characterized by the preponderance of hematite over magnetite; a transition unit of well-banded magnetite-bearing iron formation interbedded with non-banded oolitic hematite; and a well-banded magnetite-quartz silicate unit at the top of the exposed sequence. The present magnetite-hematite ratios of different units within the orebody are considered to be a primary (post-diagenetic) feature of the original sediment. Subsequent regional metamorphism has increased the grain size of the original iron oxide minerals, but did not appreciably alter the oxidation state of the original sediment.

Jan 1, 1964

By Karen M. Kessen

The isotopic variations of lead from Mississippi Valley galenas have long been used to place constraints on the sources of the lead, and on the residence the of the lead in crustal reservoirs prior to its emplacement in the Mississippi Valley province. Similar studies based on strontium isotope variations in gangue minerals associated with the lead-zinc sulphides have been neglected until Haden's (1) study of such minerals from several localities in northwestern Ohio. His work revealed two things about the mineralization. Firstly, it shoved that the average isotope composition of lead from galenas from northwestern Ohio lies on the anamalous lead line characterizing Mississippi Valley-type leads, albeit at the least radiogenic end of the entire data array. This confirm earlier assignments of the Ohio mineralization as Mississippi Valley-type (Hey1 and others (2)). Secondly, Haden (I) showed that the strontium in the calcite, strontianite and fluorite is broadly similar in isotopic composition to the strontium in the host Silurian to Devonian marine carbonates within which these minerals arc emplaced. He concluded that the mineral strontium my have been very locally derived, from the carbonate hosts.

Jan 1, 1979

By Fritz F. Prugger

This paper considers some of the main aspects of underground mining in the flat, rich, but deep lying deposits of Saskatchewan. It briefly describes the pertinent geological features as they relate co mining and the practical de-stressing techniques used to allow productive extraction in the high stress environment present in many of the province's mines. Fining layouts, materials handling and the evolution of some of the world's largest mining equipment are examined.

Jan 1, 1980

By Martin F. Grier, Nicholas H. Kempton

The Mt. Todd Gold Project in the Northern Territory is a joint venture between Billiton Australia Gold Pty. Limited, a wholly owned subsidiary of Shell Australia Limited, and Zapopan NL. As manager of the project, Billiton is guided by Shell's corporate policy that foremost consideration be given to protection of the environment from unacceptable impact and that sound environmental programmes are to be implemented effectively at all company operations. This policy on Health, Safety and the Environment helps operating companies in addressing environmental matters in a systematic way and gives guidance on the practical implementation of a range of controls to protect the environment. Most importantly, it seeks to do this in a co­ operative rather than adversarial manner. In developing the Mt. Todd Gold mine the joint venturers' environmental objectives have therefore been to plan and operate the project consistent with the highest industry standards and community expectations and in accordance with all Northern Territory government requirements. A development strategy has been designed which minimises environmental effects. Planning priorities have focused on the successful co-existence of the mine with an endangered species of bird, the Gouldian Finch, which breeds in the area; the mitigation of impacts on surface and ground. water qualities; and the protection of significant Aboriginal cultural and archaeological sites.

Jan 1, 1991