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By Wang Yingmin, Xu Zhuyun

There are 3 steps in the process of forming a mine ventilation system, (1) selecting a reasonable ventilation pattern (included pit shaft arrangement); (2) optimizing of the ventilation network and (3) computing and outputting the flow splitting results of the network with the optimal ventilating equipments selected. In the past, the first step was relied on artificial decision-making. In order to design a common ventilation system, some ventilation experts were needed to participate or do some examinations. Even so, the design made was reasonable only for those experts. If there is a mistake in the first step, then even the followed 2 steps are best done, the losses are very difficult to retrieve. So that, the first step is very important. The development of expert systems provided an efficient means and tool for all engineering fields. This paper presents an expert system of selecting mine ventilation pattern and pit shaft arrangement. After testing many times, it is shown that the system can perform the first step of designing a mine ventilation system, and can help the experts doing their study works more efficiently.

Jan 1, 1991

Marble has been recognized as a valuable natural resource ever since ancient times. Due to its peculiar aesthetic and technical characteristics as well as the lithotype uniqueness, it has widely been appreciated over the past centuries. In present times its production and demand are enjoying an increasing trend, with comparatively high market prices. All this considered, marble can be included among these natural resources whose exploitation provided, and still provides, an important contribution to the growth of the economic system. Nevertheless, there is at least one more important reason that makes marble a valued resource. For ages, marble represented one of the most important raw materials for sculpture sand architectural masterpieces, which constitute part of the cultural heritage of mankind. With this in mind, the value of marble is strictly related to its extraordinary capability to preserve cultural heritage and therefore to convey civilization from past to future generations. In other words, the role of marble should be recognized as being of the utmost importance in order to attain an overall objective of ?cultural sustainability?, that is, the assurance of the inter-generational flow of the cultural heritage capital. To achieve this sustainability goal, the priorities should be to protect and preserve the world?s artistic and architectural historical heritage, which require restoration works. In this field, a very il task is entrusted to the extractive industry: this industry, in cooperation with historians, art experts and public authorities, is in charge of detecting and supplying historical stones for restoration purposes, taking into consideration that, in order to restore a monument in a correct way, the same lithotypes the monument was made from are needed. These marbles are often no longer in production, so that it becomes necessary to find the location of the original quarries, as only there is it possible to extract even the small quantities of stones that are needed. In this case, the stone, located in its geological context, could have such valued characteristics as to be considered an important public asset and consequently a resource to be preserved and protected even beyond the market conditions. This important task should be carried out by the public administration through a targeted intervention of territorial planning and monitoring, which could include the support for the specific extractive activity.

Jan 1, 2003

By M. Irish

This paper describes the emergency water control measures used at Pegasus Gold's Zortman Landusky mine during the September 1986 flood. The amount of solution stored increased by approximately 78 165 m3 due to receiving 0.2134 m of rain in a 24 hour period. Three methods of water disposal will be discussed including continuous chlorination, batch chlorination, and reverse osmosis. A water management program will also be discussed.

Jan 1, 1988

By M. J. Sapko

The Bureau conducted, through joint funding with the Colorado Mining Association, large scale oil shale rubble fire tests to investigate flotability characteristics and different methods of extinguishment. Ignition of large rubble piles was easily accomplished. Foam blankets could be used to control surface flames. The results of these large scale tests confirmed that water was effective in extinguishing deep seated oil shale fires but not particularly efficient. It took up to 1.7 times as much water to extinguish a fire as anticipated on the basis of a simple cooling model, assuming 100 pet utilization.

Jan 1, 1989

By A. R. Przybylek

A fluid bed dryer has been designed for a nonconventional application to upgrade the value of fine anthracite culm and silt recovered from culm banks and anthracite tailings pond beds. This material can be seen as large spoil piles scattered throughout the anthracite coal regions of Eastern Pennsylvania. Engineering of the system commenced in December of 1986 and at this writing start-up is scheduled for late October or early November of 1987. This paper will focus on generalities concerned With system design and operation, and qualify the differences from conventional fluid bed coal drying systems.

Jan 1, 1988

By Phoebe L. Hauff, Jeffrey P. Kurtz, Paul D. Chamberlin

Clay minerals can be a source of problems in heap leaching operations. The ore for many heap leach operations is commonly acid-sulfate alteration zone rocks which may be found in hot springs deposits as well as the supergene zone of other near- surface gold deposits. Clays can be important constituents of these ores. Swelling clays, such as smectite, can come loose from the agglomerated ore, migrate within the heap, concentrate in pore spaces and often plug up flow channels in the heap Cement is often added to the ore as a binder during the agglomeration process. Lime is added for pH control. Their presence, combined with the sodium cyanide commonly used to leach, can raise the pH of the leach solution to 10 or even 12. This very alkaline solution can cause dissolution of some mineral Some clays, such as kaolinite, are not very stable in high pH solutions. They can be dissolved and reprecipitated as other clay species if sufficient silica and the appropriate cations are available in solution. Silica gels and amorphous materials can also be created from the dissolved kaolinite and other minerals and act as retardants to the flow of leach solutions in the heap. Therefore, before a heap leach operation is built, the operator should evaluate the clays in the ore and test the agglomeration procedure. It is important to know not only the mineralogy and the chemistry of the leach environment but how the minerals and solutions interact and what the products of this interaction are. A hypothesis is presented in this paper that expanding smectite- bearing clays can be generated within the heap. How and why this happens will be explained.

Jan 1, 1987

By G. J. Grott

Direct Production Costs for Solar Sa 1t approximate the trucking cost for 160 Km. Operations near markets appear unusually attractive at first look. However, many desert operations have been plagued by dust storms yielding salt too high in insolubles for most uses. This paper relates the history of a successful operation in a dust storm area. Saturated brine from the solution mining of LPG storage caverns is evaporated in solar ponds yielding 99.95% sodium chloride (dry basis). Purchased energy is one-eighth that of vacuum pan operations. Production scale tests have proved it works at another desert location using a more complex brine. A new approach for refining soluble salts at ambient temperatures is demonstrated by bench scale and pilot work. Again, savings in purchased energy exceed 80%, even when temperatures are raised to reduce refining time.

Jan 1, 1988

By T. Brasier, K. Oakes, S. Crabtree, B. Lusk

Destructive wave interference has been studied in theory for many years. In application however, limited information can be found. Recently, circumstances have enabled a multidisciplinary team to utilize electronic detonators and seismograph analysis to create destructive wave interference in an underground production blasting application. Springfield Underground, located in Springfield, MO, in conjunction with Orica, ETI, White Industrial Seismology, and the University of Missouri – Rolla has shown the ability to use destructive wave interference in underground blasting to reduce ground vibrations directly above. In order to develop additional reserves a reduction in vibration levels was necessary for tunneling under the Springfield Municipal Water Supply. The paper discusses the process by which the reduction in vibration was achieved in practice, as well as a technical explanation of the effects of destructive wave interference and sacrificial holes.

Jan 1, 2006

By Jr. Smith

Industrial minerals are just other rocks, except for the unique characteristics that make them useful in an industrial process. There is not a ready market for this type mineral and one or more uses must be developed to sustain production. The name "olivine" is a generic term used to indicate a group of orthosilicate minerals in a solid solution series, with forsterite (Mg2SiO4) and fayalite (Fe2SiO4) as endpoints. Since neither is found alone in nature, the mineral is always a combination of the two. The commercial deposits are high in magnesium and on the high end of the melting scale in the series. The name comes from the olive-green color.

Jan 1, 1992

By V. G. Matziaris

The differentiation between saturated and un-saturated soils becomes necessary due to basic differences in their nature and engineering behavior. The most important difference is the existence of a suction zone, above the water table, in unsaturated soils. Pore water pressure in this zone is always negative and the shear strength is greater than the one in saturated soils. This is due to an occasional and apparent component in the Mohr-Coulomb equation, which appears in unsaturated soils. In slope stability analysis of unsaturated soils, the factor of safety increases due to this occasional cohesion component of the shear strength. However, the suction zone tends to disappear because of rainfall. In these cases the factor of safety decreases and eventually the slope may fail. In this article, a parametric study of the effect of suction zone fluctuation due to precipitation in slope stability is examined. For this purpose a Combined Hydrology and Stability Model (CHASM) has been applied.

Jan 1, 2005

By Merrill P. Allen

The Vernal phosphate rock concentrator is located in the Uinta Mountains near Vernal, Utah. Ore is sedimentary rock from the Phosphoria Formation. Truck and shovel mining is done at a rate of 11,500 TPD. Run of mine ore is crushed and then milled through a SAG mill and ball mill to minus 16 mesh. Milled ore is deslimed using cyclones and hydrosizers. Sands are conditioned with fatty acid, petroleum sulfonate, diesel fuel and frother prior to primary rougher and cleaner flotation. Primary flotation tailing is milled to 95% minus 48 mesh, deslimed in cyclones, conditioned using reagents previously described, and then processed through rougher and cleaner scavenger flotation. Product of scavenger cleaner concentrate is upgraded by reverse flotation of dolomite. Flotation concentrates are combined and dewatered, pulp being milled to 99.5% minus 65 mesh and then thickened to 65% solids. Product is pumped from storage through a 10 inch, 94 mile pipeline to a conversion plant at Rock Springs, Wyoming. Mill tailing is stored behind an earthen dam, water from the settled tailing being reclaimed for mill use.

Jan 1, 1993

By Changwoo Lee, Jan M. Mutmansky

Introduction Recognition of Coal Workers' Pneumoconiosis (CWP) as a major occupational disease has affected various aspects of the coal mining industry in the United States as well as in almost all major coal producing countries. Regulations related to the control of coal mine dust forced mine operators to modify their mining and ventilation practices. As the coal production record of the last 15 years shows, this had both direct and indirect impacts on the productivity and production costs. To identify the causes of CWP, many research efforts have been made through- out the world. Most of these studies were epidemiological in nature, attempting to pinpoint exposure and seam variables that affected the incidence of the disease. Other studies have been oriented toward the elemental and mineralogical composition of the coal dust in the mine atmosphere and in the miners' lungs. These studies indicate that there may exist some relationships between the characteristics of the coal mine dust and the prevalence of the disease. Some of the variables that are thought to affect the occurrence of CWP are the mass of the dust in the working place, the rank of the coal, the existence of certain trace elements, the free silica content of the coal, and the existence of other minerals in the respirable dust. A more complete description of these previous re- search studies has appeared elsewhere (Mutmansky and Lee, 1984). The behavior of particles in the human lung is known to be governed by their aerodynamic diameter, which is defined as the diameter of a hypothetical spherical particle with unit density that exhibits the same settling velocity as the given particle. Because of this fact, the aerodynamic size distribution of coal mine dust is one of the parameters to be determined along with the other physical, elemental, and mineralogical characteristics. The objective of this paper is to establish a strategy for providing coal mine respirable dust samples for characterization purposes using instruments that classify according to the aerodynamic diameter. In addition, several findings concerning characterization methods will be presented. Choice of Samplers Most of the gravimetric dust collection devices that can be utilized in a mine environment can be

Jan 1, 1986

By Alice Blount, F. Patrick Carr

The quantitative evaluation,of quartz and other minerals in acid-insoluble residues from carbonate rocks and other industrial mineral products derived from sedimentary and low-grade metamorphic rocks is difficult. Commonly there are a dozen or more minerals present, and the suites vary from sample to sample. Because of these factors, either the absorption coefficient must be determined on a sample to sample basis or an internal standard must be used. Internal standards in general use are unsatisfactory. For example, [A1203] is often present in product samples because of ceramic grinding elements used in their production; CaF and LiF have peaks which overlap or nearly overlap mineral peaks in the samples. A careful evaluation has shown that magnesium aluminate (synthetic spinel) works particularly well as an internal standard for these types of samples. Not only does it have few, strong diffraction peaks which do not overlap, the peaks are in the same 28 region as the minerals, usually quartz and silicates, for which quantification is desired. Spinel also consists of equidimensional particles without prominent cleavages; this promotes a random orientation of the minerals in X-ray diffraction mounts. In addition, spinel can be used to correct for loss of diffracted-beam intensity due to thin sample preparations which are often unavoidable.

Jan 1, 1991

By D. A. Stanley

The Bureau of Mines has developed an equation which describes the dewatering of clay slurries with polyethylene oxide. This dewatering equation is An _ kC + b where n, k. and b are empirical constants and C is the concentration of polymer solution used for dewatering. The minimum amount of polymer required for dewatering. A is determined by titration of the clay slurry with a polymer solution. In this report, the dewatering equation is applied to data obtained for a polyacrylamide dewatering sequence. Fundamental similarities between the dewatering properties of clays and the viscosity of polymer solutions were observed. These similarities were explained by correlating an equation describing polymer configuration in solution with the dewatering equation. This correlation showed that amount of polymer required for dewatering and polymer solution viscosity are both consequences of the frictional interaction of entangled polymer coils.

Jan 1, 1989

By Sandra L. Maxfield, Alan Mair

Strategic design of groundwater monitoring programs can increase public confidence in mine management, decrease financial assurance requirements, and minimize environmental budgets. Monitoring of inorganics is challenging because many occur naturally with baseline concentrations fluctuating spatially or temporally. Evaluating monitoring data to distinguish between a hazardous release or a natural fluctuation in baseline concentration can be controversial. In order to develop an effective program, monitoring parameters should be selected which are mobile and stable. Statistical procedures should be customized to address the uniqueness of groundwater systems. Calculated baseline concentrations should minimize the false negative & false positive rate.

Jan 1, 1995

By M. G. Skowroski, G. G. Eichholz, J. P. Ambrose

Introduction It has long been known that there are extensive deposits of phosphate-bearing deposits in the Coastal Plain of Georgia in many locations that are similar to those being mined commercially in central Florida. A major drilling program was conducted in 1966-67 by the Georgia Geological Survey (GGS). The economic potential of some of the material uncovered was evaluated at that time by a team at Georgia Institute of Technology led by Dr. J.E. Husted. There were some promising results. Since then, there has been little commercial interest in pursuing this matter, though the potential for development remains. In the long term, Georgia's phosphorite deposits could be a major source of income to the state if they were commercially processed. Phosphorite deposits contain significant levels of uranium and thorium. Uranium concentrations in Florida phosphate aggregates have been found to be 120 to 140 ppm. The presence of high concentrations of uranium means that there is a small but finite concentration of radium, which subsequently leads to radon gas emanation. It is the radon emanation and its progeny that may pose the largest health problem in many types of mining. Surface mining operations can possibly elevate the radon and radon daughter concentration in the vicinity. There is always some public concern whether any increase in the radon concentration in the atmosphere by mining (surface mining in the phosphorite case) could elevate the risk of cancer in the nearby population. At the present time, a great deal of attention has been devoted to the possible health effects of radon and its decay products in the inhaled air in mines and inside buildings built on mill tailings or uranium-bearing rock (Gesell and Lowder, 1980). Several evaluations have been published on the potential health effects of the Florida phosphate operations (Guimond and Windham, 1975; Roessler et al., 1980; Travis et al., 1979) and for buildings incorporating phosphate slag aggregates (Kahn, Eichholz, and Clarke, 1983; Roessler, Roessler, and Bolch, 1983). They all indicate that such potential effects are small, but tangible, compared with other radiation effects, for instance in the nuclear industry (Cohen, 1981). In view of the current concern, especially by the US Environmental Protection Agency (EPA), with the radiological consequences of large-scale mining of uranium-bearing phosphate rock (Guimond and Windham, 1975), it was decided to assess the potential radiological consequences if the Georgia deposits were developed. This paper presents an attempt to estimate the magnitude of any radon-based health effects that might arise from future mining operations in selected areas of the Georgia coastal region. To do this, a calculational model was developed that took into account the mining operations themselves, the atmospheric dispersion of the radon released, and the radon daughter concentrations in nearby towns. The model was applied to both extremes. The first application was a hypothetical mining operation in Echols County. Echols County is very sparsely populated and, unless living very close to the site, a person would probably experience little radiation exposure, if any. The model tries to prove this point. The second application was at a site near Savannah, Georgia. Both sites contain economically feasible phosphorite deposits and were not entirely hypothetical in that sense. Site selection In the course of the South Georgia Minerals Program (Furcron, 1967), an extensive series of drill core samples had been collected from various mineral occurrences in the coastal plain. It was found that the cores from the previous drilling program (Furcron, 1967), though carefully preserved, were not readily accessible. But the GGS reports did contain gamma logs of all the holes surveyed. With the cooperation of Dr. Neal Shapiro of the Survey, some core samples were selected and assayed, and used to calibrate the gamma log data. Samples from locations known to have detectable radioactivity were screened and counted. Their measured uranium content was used to calibrate the gamma log profiles for those same holes as obtained by the GGS. On this basis, two of the higher-level sites were selected and the calibration was used to obtain integrated uranium concentrations over the length of the borehole. It is customary to describe radon and radon-daughter concentrations in "working levels" (WL), where one WL represents a concentration of radon daughters capable of releasing 130 000 MeV of alpha particles, equivalent to 100 pCi of radon in equilibrium with its daughters per liter of air. A representative concentration is 0.15 WL, below which radon levels are widely considered to be negligible. For the mine sites selected, the surface area and rock volume were determined to estimate their radon content. Working-level values were then estimated for the assumed radon release from the crushed ore and the exposed surfaces of the mine pit. According to Kisielewski (1980), 93.4% of all radon released from open-pit operations is released from the ore zone; thus, the calculations assumed that those surface areas were the main sources.

Jan 1, 1987

By R. E. Miller

Accelerometers and pressure transducers mounted in suspension components can be used to monitor the ride of haulage trucks. Presently, it is difficult to tell what caused a jolt to the truck using either pressure or acceleration data alone. When information from a Global Positioning System is recorded at the same time as shock pressures or acceleration data, then the exact location of an event can be determined. Mine management can then determine what caused the jolt to the truck.

Jan 1, 1999

By X. Wu, M. Karfakis, E. Topuz

The generalized ventilation network problems encompassing both natural and controlled splitting networks, is formulated using a nonlinear nonconvex programming model, which has not yet been solved satisfactorily. This paper presents a methodology which can deal with the problem. The proposed methodology converts the nonlinear problem into a linear problem, by using special ordered sets of variables, and optimizes it by a modified branch and bound technique. The global optimality of the methodology and its applicability to different cases are investigated

Jan 1, 1991

By Walter E. Heinrichs

This case history really started during the tail end of WWII when two Navy men, both Colorado School of Mines graduates, got together in Washington, DC, while they were assigned to the Office of Navy Petroleum Reserves doing some of the first aerial magnetometer work ever done on a practical oil exploration basis over the offshore area of the Gulf Coast. When separated from Naval Service active duty in 1946, the two men, Walter E. Heinrichs, Jr., and Robert E. Thurmond, tried, unsuccessfully, to form a commercial air magnetometer business. Later they got together again in Jerome, AZ, with Newmont Mining's early geophysical exploration endeavors from 1947 to 1949. Subsequent to the Newmont experience, they jointly proposed a specific mining geophysical exploration and development program to Herbert Hoover, Jr., then president of United Geophysical Co. of Pasadena, CA. Mr. Hoover, in consultation with his father Herbert Hoover and others of his staff at United, particularly Edwin G. Schempf, executive vice president, and Raymond A. Peterson, vice president of research, agreed to establish the proposed program under United's auspices, to be headquartered at Tucson, AZ. The primary objective would be to practically test and develop various mining geophysical methods and techniques while exploring particularly for base metals in the general area of southeast Arizona and southwest New Mexico.

Jan 1, 1991

By K. E. Hjelmstad, W. H. Pomroy

In the event of fire underground, it is essential that all miners be warned as quickly as possible. With mine air rapidly depleted of oxygen and contaminated with smoke and toxic fire gases, any delay in the warning signal could have disastrous consequences. Unfortunately, present mine fire warning systems, such as stench, audible or visual alarms, telephones, and messengers, are often slow, unreliable, and limited in coverage. Recent research by the US Bureau of Mines has established the feasibility of ultralow frequency electromagnetic signaling for underground mine fire warning. Infield testing completed thus far at five mines, signals of from 630 Hz to 2000 Hz were transmitted through rock up to distances of 1645 m (5400 ft) to a pencil-sized ferrite-core receiving antenna and intrinsically safe receiver circuit. Theoretical analysis indicates a capability to transmit effectively for distances in excess of the maximum depths of most American mines, which is about 900 to 1000 m (2950 to 3280 ft) . The prototype system uses off-the-shelf components and state-of-the-art technology to ensure high reliability and low cost. This technology would enable simultaneous and instantaneous warning of all underground personnel, thereby in- creasing the likelihood of successfully evacuating a mine during a disaster. This report discusses the theoretical basis for through-the-rock ultralow frequency electromagnetic transmission, design of the prototype transmitter and receiver, and the results of in-mine tests of the prototype system.

Jan 1, 1991