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By K. N. Santini

The evaporite deposit at Searles Lake consists of alternating brine-saturated saline beds and saline-bearing mud beds. Three major subsurface brine-saturated saline horizons have been identified by private companies and the U.S. Geological Survey. They have been termed, from bottom to top, the Mixed Layer, Lower Salt, and Upper Salt. The important water-soluble components (Na, K, Mg, CO3, HCO3 , SO4, Cl, and B407) are either in brines or have combined to form the following minerals: halite, hanksite, trona, nahcolite, burkeite, borax, thenardite, northupite, sulfohalite, glaserite, etc. Kerr-McGee Chemical Corp., the current operator at the lake, selectively pumps interstitial brines from each of the major horizons to feed its three chemical plants. As the pumping continues, brines are continuously replenished within the deposit by dissolution of the minerals through natural recharge or artificial fluid injection (solution mining). The brines are processed to produce a variety of chemical products, which include sodium carbonate and sulfate, potassium chloride and sulfate, sodium borate, and boric acid. The Anaconda Minerals Co. has been evalua¬ting potential domestic trona acquisition since 1981. We have evaluated various properties in the Green River, Wyoming trona district, and Owens Lake and Searles Lake in southern California. In 1983, we purchased with our joint-venture partner, Leslie Salt Co., the southern portion of Searles Lake from Occidental Petroleum Corp. Since mid-1983, Anaconda has been conduct¬ing a small exploration-drilling program at the property. The initial core holes were drilled along and adjacent to the existing access road. In 1984 we used an all-terrain drill rig to gain access to drill sites on the playa where no roads exist. The use of this equipment proved to be highly successful. The drill program consists of coring to an average depth of 450 feet and collecting brine samples from potentially commercial horizons. The brine samples are collected by setting a packer and swabbing the hole. The core is logged and split lengthwise; one-half is submitted to our Tucson Geoanalytical Laboratory for semi-quantitative mineralogy by X-ray diffraction and the following suite of chemical analyses: Na, K, Mg, C03, HCO3, SO4, Cl, B407, Li, H20 insolubles, and acid insolubles. Additional test work for selected core samples will include effective porosity and horizontal permeability determinations. The brine samples are subjected to the same suite of chemical analyses (minus insolubles) as the core samples. In addition, specific gravity is also determined. Both cross sections and isopach maps are being constructed. The hydrological characteristics of the potentially commercial horizons are also being investigated.

Jan 1, 1987

By Gerald G. Griswold, James O. Greenslade, Cherie Tilley, Richard Reseigh

INTRODUCTION The Harrison Western Corporation, a leading Denver based mine contracting and engineering concern, is presently engaged in sinking two 1,006 m (3,300 ft) shafts for the Phillips Uranium Corporation at their Nose Rock Project, approximately 13 miles northeast of the small community of Crownpoint in McKinley County, New Mexico. The Nose Rock Project is the first attempt by the Phillips Uranium Corporation to tap the deep uranium reserves in what has become known as the Grants Mineral Belt. (See Figure 1) Project Description Phillips Uranium Corporation's plan for the large 2700 metric ton per day (2950 tons/day) mining facility calls for a series of deep access and ventilation shafts ranging from 4.27 m (14 ft) to 5.49 m (18 ft) in diameter to approximate depths of 1,006 m (3,300 ft). The initial pair of shafts consists of one production shaft and one ventilation shaft separated by a distance of 91 m (300 ft). The interbedded layers of sedimentary sandstones and shales to be penetrated by the shafts contain several major water producing aquifers, the deepest being the mineralized zone called the Westwater Canyon Member of the Morrison Formation.

Jan 1, 1981

By Grant Davis

An International Symposium on the Ecology and Revegetation of Drastically Disturbed Areas was held at the Pennsylvania State University in August 1969. Scientists from 13 foreign countries and 18 states in the United States attended this meeting, which focused on those areas disturbed by mining. The symposium enabled scientists from all over the world to get together for two weeks and discuss informally some of the knotty problems of reclaiming these disturbed areas. Trying to present the results of each of the 64 papers delivered at the symposium might be difficult. So, I will try to bring you up to date on the general status of research on the reclamation of surface-mined areas, particularly in revegetation and hydrology. I will also mention some research that is under way but was not presented at the symposium.

Jan 1, 1970

By S. K. Kawatra, S. J. Ripke

During 1998, 62 million tons of iron ore pellets valued at $1.7 billion were shipped from U.S. mines. These pellets are the primary source for domestic iron and steel production. During pelletization, binders are required to improve the green strength of the pellets. Each year, bentonite binder costs a typical plant from $3 million to $5 million. Reducing the bentonite dosage has the advantages of significant cost savings while producing higher quality, lower silica pellets. The authors have recently identified a new and important bentonite binding mechanism, the fiber theory. During this study, procedures were developed that took advantage of the ability of bentonite to form fibers, and resulted in a dramatic decrease in the necessary bentonite dosage. Acceptable quality pellets were produced with the bentonite dosages reduced in half from 14 lb/lt (0.66%) to 7 lb/lt (0.33%).

Jan 1, 2001

By Jon C. Yingling

A control system for reducing peak loads on mine conveyor networks is proposed. The system involves continuous monitoring of flows into the conveyor network and section feeders with variable discharge capability. The control strategy uses differences in material transit times from various production units to the transfer points in the network to forecast load levels that will be intersected by the discharge of the controlled feeders over future time intervals. Feeder setpoint adjustments are made to prevent excessive peaks in the combined flows at the transfer points, while maintaining adequate feeder throughflow to avoid production bottlenecks.

Jan 1, 1992

By C. Woofter

Quarry operators must continue to change and adapt environmental compliance methods to meet the increasingly demanding regulations. To fulfill industry needs, a computer-based decision support system is being developed to facilitate decision making that mine operators are required to make regarding environmental responsibilities. This system can help to determine permitting and compliance measures needed for air, surface water, groundwater, noise, aesthetics, vegetation, wetlands, hazardous wastes, storage tanks and wildlife habitats during the development, operation, and closure phases of mining. Operators will utilize the system's user-friendly interface consisting of mouse driven responses and limited keyboard entries on a desktop computer. The system is easy to upgrade according to the user's needs and changes in current laws and regulations. Data input models, user interfaces, and support of decision making are explained. The program permits inclusion of the decision maker's own insights through "what-if' analysis, in which the user can change ad hoc entries and check the related consequences. Using this approach, the user has complete control over all steps of the decision making process. A storm water example is selected to demonstrate the potential benefits of the support system to environmental decision makers.

Jan 1, 1995

By B. I. Pålsson, H-Å. Häggblad, J. F. Stener, P. Jonsén

"Understanding mill charge motion is important. In the charge, the center of gravity is shifted from the rotational center of the mill system, and its motion is induced by rotation of the mill. At the same time, the charge creates a torque in the mill system. Breakage of ore particles and wear of liners/ball media are closely linked to this motion. To study these phenomena in a physically correct manner, numerical models for different parts of the mill system are needed. Validations of such models are scarce, because of the difficulty of measuring inside a tumbling mill. Experimental measurements in a lab mill were done for a number of load cases: varying feed material, mill filling, mill speed and pulp liquid. The mill is set up to measure the charge-induced torque. The accuracy is good, with relative uncertainty less than ± 2% for relevant load cases. A full three-dimensional numerical model of the whole mill is used to predict induced torque. Agreement between predicted and measured torque at steady-state is good. In addition, the model can accurately predict the mill startup behavior for torque and mill power. This proves that the model is physically correct, and can be used for modeling large-scale mills.IntroductionUnderstanding of the charge motion within the mill is of importance in mill optimization. The breakage of ore particles and the wear of liners/ball media are closely linked to the charge motion. To study these phenomena in a physically correct manner, appropriate numerical models for different parts of the mill system must be used. Validation of these models is of major importance. This has led to an increased interest in obtaining an accurate and direct measurement of mill load and the behavior of the mill charge.For structural analysis, the finite element method (FEM) is the most developed and most frequently used numerical method. FEM is a numerical solution method based on continuum mechanics modeling. A constitutive relation for the actual material is described, and the governing equations are solved in Zienkiewicz and Taylor (2000). Varieties of different constitutive models for a large number of materials are implemented in modern FEM code. The computability of nonlinear problems in solid mechanics is investigated in Belytschko and Mish (2001), among others."

Jan 1, 2015

By Robert L. Wade

The two primary goals in underground coal mining are to improve safety and to lower mining costs per ton through increased productivity. However, as evidenced by the drastic decrease in. productivity since the enactment of the 1969 Coal Mine Health and Safety Act, (the Safety Act), these goals appear to be mutually exclusive. Millions of dollars have been spent in the res, arch and development of systems to solve this problem. Before the Safety Act, "productivity had experienced a 25-year history of continued increases ...? (Douglas, 1980). But since its enactment there have been dramatic decreases in productivity accompanied by phenomenal increases in mine costs. Labor trends, depletion of the more readily minable underground coal reserves and other factors have contributed to this situation, but the dominant factor is undoubtedly the Safety Act itself. To illustrate, prior to 1969 underground coal mine production was much greater than surface mine production but since then underground mine production has been declining at a rate greater than the overall growth rate of total coal production.

Jan 1, 1985

By R. L. Hills

America's industry uses about 44% of the total energy consumed by the nation directly as fuel burned in industrial plants or indirectly as fuel burned by utilities to provide electric power. In addition, industry requires raw materials or feed stocks derived from fuel sources or having fuel value. This represents about 11% of total U. S. energy consumption, bringing industry's portion to about 55%. Adding that portion of energy consumption required by the transportation sector to move raw materials, intermediates, and finished products, the total energy impact of industry approaches 213 of total U. S. consumption. It is obvious that American industry has the largest share in the task of balancing energy demand and supply. What are we going to do? -- We must increase the supply of energy and increase the beneficial results obtained from each unit expended. Both avenues, unfortunately, are limited in extent and speed. Increases in supply cannot occur without drastic and permanent increases in cost. These increases in cost are un- desirable and inflationary but do provide incentive for the rational businessman to expend the effort and money required to improve the effectiveness of energy in industry.

Jan 1, 1975

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

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

Jan 1, 2016

By Gene M. Handel

Today the world is heavily dependent on petroleum for its energy. In the United States, over 75% of the primary energy used comes from petroleum. Other developed countries are similar. The less developed countries have a lower dependence on petroleum just as the United States did through the early 20th Century. However, these less-developed countries look upon petroleum as one of the primary energy sources for the economic growth required to improve their standard of living. So everyone considers petroleum an essential ingredient in the recipe for the good life. But there is a substantial problem with this recipe, and it is finally getting general recognition. Petroleum is a finite resource, and the world is using it up at a rapid, accelerating rate. Though it won't be exhausted for many decades, the early warnings of ultimate limits have already appeared. The suppliers of the incremental production in the Middle East have threatened to restrict increases in their production rates. And, of course, the short term embargo of four years ago clearly demonstrated the economic impact of reduced access to petroleum as a primary source of energy. World petroleum production will probably peak in. 10 to 15 years and then start declining. When that happens, economics--the allocation of scarce products (also known as the dismal science for obvious reasons)--indicates that the price of petroleum will escalate in real terms. So that's the situation today. We have a serious and growing problem facing us that could substantially alter the quality of our life over the next 25 years. Recognition that the society may face a period of lowered expectations after a long period of upward mobility will be a painful experience, but it is certainly not the moral equivalent of war. And, besides, we have time to take positive actions to avert the most serious consequences. When we consider alternate energy sources, the possibilities are almost endless: coal, oil shale, tar sands, solar, fission, fusion, wind, tides, biomass, etc. Actually, the list is endless because new possibilities are continually being proposed. Of these possibilities, coal uniquely stands out as an attractive substitute for petroleum. Coal can be, and is, burned to generate electricity and provide heat. It can be liquefied to supplement the liquid fuels from petroleum, and it can be gasified for use as synthetic natural gas. Unlike exotic alternate energy such as solar and fusion, coal has successfully been used commercially to produce synthetic fuels. But, the technology does need to be refined and modernized. Thus, coal's role is not to be "America's Ace in the Hole," but to bridge the transition from primary dependence on petroleum for energy to the utopia of renewable sources of energy. But don't be mislead by the prophets--those renewable sources of energy are going to be very, very expensive when they are invented.

Jan 1, 1978

By J. H. Desautels

The modern coal mining industry is subject to a vast array of regulations affecting virtually all aspects of its operations. Probably the most significant over-sight role involves the Office of Surface Mining Reclamation and Enforcement (OSH) established by the Surface Mining Control and Reclamation Act, or SHCRA.1 Although complying and coping with SHCRA can be difficult for coal operators, this complex regulatory process has helped insulate the industry from ongoing efforts to extend regulation under the Resource Conservation and Recovery Act, or RCRA, 2 to aspects of the mining industry in general. The Environ-mental Protection Agency (EPA) has struggled with regulation of mining wastes under RCRA since the mid-1970's, but RCRA itself places most coal mining wastes firmly under the control of OSH and SHCRA. Despite the general exemption from RCRA regulation for waste materials that result from extraction and processing of coal itself, there may be circumstances under which coal mining operators could find themselves subject to regulation under RCRA or a number of other statutes administered by EPA. This paper will review briefly the history of mine waste regulation under RCRA, as well as touch on the policy decisions that led to the exemptions from RCRA regulation. The paper will summarize coal waste requirements under SHCRA, and also will review what operations at coal mines need to be controlled, in order to avoid potential liability under RCRA. In addition, it will mention requirements under other federal laws, including CERCLA, or the "Superfund" law,3 and describe how they may impose restrictions or liability on coal operations for waste or other materials commonly found at surface and underground coal mines.

Jan 1, 1993

The amount of hydrophobic materials constituting the mineral froth strongly influences the froth viscosity. Higher froth viscosity on the other hand can retard the drainage of physically carried over hydrophobic particles. In phosphate flotation tests a direct correlation was observed between froth viscosity and recovery and an inverse correlation between froth viscosity and grade. Phosphate flotation tests in the presence of a silica depressant indicated that higher froth viscosity is an effect rather than a cause of silica particles reporting in the froth.

Jan 1, 1992

By D. K. Adjei, G. Ofori-Sarpong, R. K. Amankwah

"Mercury (Hg) is toxic and has long-term effect on the muscle tissues, the brain and the central nervous system functions due to its bioaccumulation and biotransformation effect. Hg pollution around the world is high and this has attracted much global concern such as the Minamata Convention on Mercury, held in 2013. For several years, mercury has been the chemical of choice for Artisanal and Small-Scale Mining (ASM) gold extraction, accounting for about one-third of the global mercury consumption. A greater percentage of this ends up in the environment through open burning of amalgam, spillage and indiscriminate disposal of waste. To break this wall of mercury pollution, it is very important for the mercury used to be recycled through the use of mercury retort units. This brings into the limelight, the Lantern Retort which tries to synergise the high conductivity of steel and the see-through effect of glass, thus, improving the amalgamation process. A research conducted on improving the original Lantern Retort arrived at an appropriate distillation length of 5.08 cm which was used in redesigning a more efficient retort. The improved Lantern Retort recovered about 98% of the mercury used. INTRODUCTION Artisanal and Small-scale mining (ASM) is an informal mining activities which employ quite simple tools such as pickaxes, sluice boxes, shovels, chisels, metal bars, mattocks and water pumps for mining and processing of gold ores. The artisanal and small-scale mining (ASM) sector has served as source of employment for many people in developing countries including Ghana (Aryee, 2001; Hilson and Potter, 2003; Amankwah and Anim-Sackey, 2004; Amankwah et al., 2010) and has provided a substantial amount of foreign exchange through its activities (Hilson, 2001; Styles et al., 2010). Hentschel et al. in 2003 estimated that about thirteen (13) million people are said to be engaged directly in the small-scale mining activities worldwide. However, an estimated 100 million people are said to depend on this sector for their livelihood mainly in developing countries. In China alone, a projected number between 3 and 15 million people are engaged in artisanal and small-scale mining activities (Hentschel et al., 2003), whilst in Ghana, it is estimated that more than 1,000,000 people are employed directly or indirectly in the artisanal and small-scale mining activities, with 10% being women (Amankwah and Anim-Sackey, 2004; Amankwah and Ofori-Sarpong, 2014). In Ghana, ASM gold production has grown from a low of 2.2% in 1989 to a high of 34% in 2014. This figure is estimated to increase with proper documentation. This indicates that the sector has made significant socioeconomic impact on many individuals and communities as a whole. Notwithstanding the above positive contributions, the sector has also contributed to negative impacts on human, aquatic life and the environment in general due to indiscriminate mercury emission. This ‘pollution wall’ needs to be broken, and several interventions have been put in place including the use of retort units like the lantern retort (Adjei et al., 2014; Amankwah and Ofori-Sarpong, 2014)."

Jan 1, 2017

By Theodore J. Barrett

[One of the earliest records of pillar removal can be found in the 16th Chapter of Judges in the Old Testament. Here we read where the mighty Sampson removed the pillars from beneath the prison house causing the collapse of the structure resulting in his own death along with the deaths of the 3,000 Philistine occupants. Our problems at the Mi Vida Mine differ somewhat from those of Sampson of old, in that it is our aim first to remove the pillars and get out from under the back before the "house falls in" and, secondly, to remove the pillars without the lose of a single life or without even a single casualty. As of January 15, 1959, the Mi Vida accident record stood at 772 days without a lost-time accident]

Jan 1, 1959

By David F. Becker

Two-dimensional, finite-difference elastic modeling aids in planning an optimum seismic-acquisition scheme to define the extent of subsurface cavities resulting from in situ gasification. To understand the seismic effects of a cavity, two models are compared and contrasted. Model A consists of a low-velocity layer (LVL) in a half space; Model B contains a rectangular water-filled cavity in the LVL. Amplitude differences are the dominant effect on the surface records for each model. Cavity resonance and diffraction effects are more definitive in vertical seismic profiles (VSP's) and in a "snapshot" of the wave field. Interpretation and subtraction of corresponding records for both models shows the need for pre- and post-gasification seismic recording. Also VSP data are more informative than surface records.

Jan 1, 1983

By C. E. Stack

For the purposes of this presentation, "refractory clay" is intended to include any clay suitable for refractory products and thus represents a description based on industrial application. Other common examples based on use would be white-ware clay, bleaching clay, paper clay, or cement clay. Most users and producers of refractories have specific quality requirements which determine the quality or type of clay that can be utilized. Many clays can however be interchanged or substituted in use by changing manufacturing processes or upgrading less desirable clays. U.S. Bureau of Mines publications (Ampian, 1985) categorize days into six groups. These are kaolin, fire clay, ball clay, bentonite, fuller's earth, and common clay. These are practical groupings based on clay production and usage in the United States. Among these groups bentonite, fuller's earth, and common clay are primarily composed of the minerals, smectite, illite, or chlorite, and are non-refractory. Kaolin, ball clay, and fire clay are commonly used in refractories and thus qualify as refractory clays.

Jan 1, 1986

By Gary Repetto

Hiring trends in the construction materials industry have remained steady through the years, with some seasonal and geographical variances. However, after several years of a depressed market, the base metals industry has begun to actively hire only over the past two years, due to the continued strength in the prices of copper, lead, zinc, molybenum, etc. The expanding precious metals industry, which for the most part escaped the depressed markets of the mid-1980s, actually preceded the base metal companies in hiring of engineers and operations personnel. The coal industry has not seemed to rebound much from the cutbacks of the early 1980s. And the uranium industry, which began its decline a year or two earlier than the other mineral industries, has remained nearly nonexistent in the United States. In nearly all of the mineral industries, new hires have been mostly in the engineering and operations areas, not exploration.

Jan 1, 1990

By R. K. Singhal

A sizable surface mining industry exists in Western Canada. There are the surface coal mines in the provinces of Alberta, British Columbia, and Saskatchewan producing the bulk of Canadian Coal. The two oil sands plants in Fort McMurray, Alberta producing synthetic crude oil are surface mining operations. Much of the metalliferous mining in British Columbia is carried out by open pit methods. This paper discusses the current surface mining methods in both of these industries with particular reference to Alberta. Issues relating to environmental impact assessment, mine reclamation and mine site closure have been dealt with.

Jan 1, 1995

By Howard L. Hartman

In 1969, the OECD conducted a survey internationally to determine the status and needs for research and development in the field of tunneling. The findings also have some validity for underground excavation in general and for underground mining per se. Of the 17 countries responding to the survey, the U.S. leads in the level of support: $21.8 million and 720 man-years of effort over the last ten-year period. The total volume of R/D for the 17 countries was estimated to be $86 million and 5800 man-years. Performance of research was primarily by government agencies and public utilities (70%); the balance was conducted by private organizations and universities (15% each). In the categories of R/D subjects surveyed, three--Wk mechanics, soil mechanics, and geological exploration--outstripped all the rest in priority of effort to date. Ground support, equipment development, excavation, and environmental control received intermediate attention. The subject areas in which the least R/D effort has been expended are materials handling and systems evaluation. For the future, those R/D areas rated the most crucial to achieve technological progress in tunneling were excavation, ground support, and materials handling. The survey findings of tunneling activity indicated (1) a disturbingly low level of R/D activity in the private sector, (2) the necessity for a reordering of priorities in directing research efforts in the future, and (3) a lack of recognition to date of the importance of systems evaluation in R/D activities.

Jan 1, 1970