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A chartered bus with about 30 attendees of the just completed 1998 SME Annual Meeting headed toward Green Cove Springs, FL, which the author had been told was located somewhere south of Jacksonville, FL. In conjunction with the meeting in Orlando, RGC (USA) Mineral Sands provided a tour of its facility. The author had worked with heavy minerals on a laboratory scale, performing the usual gravity and magnetic separations, but had never been to a heavy mineral mine and processing facility. Years ago as a metallurgist, the author once applied for a job in a heavy mineral operation in Florida -it may have been the same operation. After turning north on to Highway 95, the endless billboards promoting beach-front retirement communities proved the Atlantic ocean was just a few miles away (although the author never caught a glimpse of it). After another hour, the bus suddenly turned west and continued inland for about 65 km (40 miles). The thought occurred, "We are talking about beach sands, what are we doing heading away from the ocean?" As the bus continued inland, the author was struck by the flatness of the land and by the lakes, rivers and wetlands. He was also impressed by the many fine stands of pine and hardwoods. The office of RGC (USA) Mineral Sands is located about 16 km (10 miles) south of Green Cove Springs. Upon leaving the bus, members of the tour were greeted by Graeme Sloan, general manager, and Elliot Mallard, manager of mining. They provided some general information about the operation, including a slide show. RGC's Florida operation produces four concentrates: zircon (ZrSiO,), rutile (TiO,), ilmenite (FeTiO,) and leucoxene (an alteration product of ilmenite containing 67% to 70% TiO,). With a work force of about 170, the annual production of the above products is about 23,27, 45 and 14 kt (25,000 30,000 50,000 and 15,000 st), respectively. RGC also has other mineral sand operations, in addition to gold and base metal mines, mostly in Australia.

Jan 1, 1998

By Greg Hodges

Sand-and-gravel aggregates have become the number-one, nonmetallic-mineral resource in the world. Surficial aggregate deposits of economic size are becoming increasingly rare in most parts of Canada. In southern Saskatchewan, this is especially true, and detection and delineation of intertill sand-and-gravel deposits with airborne electromagnetic (EM) surveys have proven very successful. Airborne and ground geophysical surveys detect such deposits by their resistivity contrast relative to the surrounding clay-rich soils. Dighem helicopter-borne electromagnetic surveys map soil variations over a large area quickly and cost effectively, greatly reducing the cost of detecting and mapping deposits compared with traditional methods (air-photo interpretation, ground EM, and drilling.). The multiple-frequency EM system used by Dighem can map variations both horizontally and vertically. Magnetic data collected simultaneously are useful in mapping bedrock geology. Both resistivity and bedrock maps aid in the important task of reducing drilling costs and person-hours in the field. The results of the survey are presented as maps of ground resistivity, which are relatively easy to interpret. These maps are produced in the field at the time of the survey, making quick follow-up of the survey possible. Airborne EM surveys can map the extent and depth of aggregate deposits more effectively than is practical from the ground. Since aggregate deposits can vary tremendously in a very short distance (<300 m) large-area EM maps can show both local area variability and also help develop intertill trends. A test survey for the Saskatchewan Highways and Transportation Department over a 3-km by 5-km area mapped all the known deposits as well as some unknown deposits, subsequently proven by drilling. The test-survey data show that the method not only detected the deposits, but also gave an estimate of the shape (volume) of each of the deposits. Comparison of the data to drill sections shows excellent correlation. Theoretical modelling demonstrates that the multifrequency system can discriminate sand and gravel from bedrock ridges. Since the successful test work, about 725 km2 of ground have been surveyed, resulting in the discovery of four new deposits, which can be used immediately, resulting in significant savings for the Saskatchewan government and taxpayer.

Jan 1, 1999

By Don Morris

The Building Products Company is Phoenix based and owned by Mission Clay products of California. Building Products is the only manufacturer of vitrified clay pipe in Arizona. The marketing area includes Arizona, Nevada, Utah, New Mexico, and California. Building Products, promoted by Arizona Public Service, was formed in 1970. Raw-materials prospecting was undertaken for 2 years, after which a $5-million plant was built. Initially, a satisfactory vitrified product could not be made with the raw materials then in hand. Subsequent prospecting and testing led to an acceptable raw-materials mix. Testing to upgrade the final product is a continuing process. The basic raw-materials supply must be adequate, secure, and capable of sustaining close tolerances in the final product. These needs are met by mining four geologic materials at three different localities: (1) refractory aluminous shales (two horizons-one pit) Colorado Plateau Province (Mogollon Rim); (2) less refractory aluminous materials from late Cenozoic lacustrine materials near Dewey in the Transition Zone (TZ); and (3) Precam¬brian "slate" from near New River along the southern edge of the TZ. Other additives include grog (ground-up, broken pipe) and barium carbonate that ties up what gypsum there is. Calcium magnesium carbonates are deleterious components that are minimized by careful selection of the mined products. The raw materials are blended and mixed, ground to 12 mesh, mixed in a pug mill, depleted of air, extruded into pipe ranging from 6 inches to 42 inches in diameter, transported to a hot-air drying room, fork-lifted to an appropriate kiln, and fired at a 1900-2000° F range. The "Rim" kaolinitic shales, being the most refractory ingredient, stabilize the pipe during the firing process. They are very plastic, and therefore facilitate extrusion. The Dewey clay fuses at a low temperature and forms an impervious glasslike binder. It also is plastic. The "slate" forms platy particles that tend to orient themselves during laminar flow. This provides strength for both the green and dried product. It doesn&apos;t absorb water, which helps the drying process. Grog remains stable during firing, and therefore helps to control shrinkage. The development of appropriate raw materials and proper mixtures has been done empirically.

Jan 1, 1987

By Adrian Smith, Debra W. Struhsacker

13.1 INTRODUCTION Cyanide is, a generic term indicating the presence of the cyanide ion (CN-). Cyanide is a very common, naturally occurring compound produced by many biochemical reactions. Many plant species synthesize organic compounds which contain cyanide in the form of cyanogenic glycosides (Knowles, 1976). For example, trace amounts of cyanide are present in the seeds and leaves of many members of the Rosaceae (rose) family (Kingsbury, 1964). Many common items such as lettuce, maize, sweet potatoes, kidney beans, (Oke, 1969) almonds, and cigarette smoke contain cyanide. As examples, a recent chemical analysis of chocolate-covered almonds measured a total cyanide content of about two ppm (Steffen Robertson and Kirsten, 1987); and the U.S. Surgeon General (U.S. Department of Health, 1964) has shown that cigarette smoke contains up to 1,600 ppm total cyanide. The chemistry of cyanide solutions is complicated because the cyanide ion forms compounds and complexes with many elements. Some cyanide species are highly toxic whereas others are relatively inert and harmless. Molecular hydrogen cyanide (HCN) is the most toxic form of cyanide. Under most conditions, HCN exists as a gas which readily dissipates or reacts with the environment to form less toxic or nontoxic forms of cyanide. Thus HCN is an ephemeral toxin, and many naturally occurring geochemical processes reduce the HCN concentration of a heap system with time. As discussed below, free cyanide includes the two species, ionic cyanide (CN-) and molecular hydrogen cyanide. Free-cyanide toxicity in man, mammal s, and aquatic species is we1 1 documented (Doudoroff, 1976; Ecological Analysts, 1979; Towill et al., 1978). The lethal doses reported for human adults vary with the type of exposure as follows: • One to three mg/kg body weight if ingested; • One hundred to 300 ppm if inhaled; and • One hundred mg/kg of body weight if absorbed. Acute toxicity of free cyanide to freshwater invertebrates ranges from 0.028 to 2.295 mg/l, depending on species and test conditions. Generally, free-cyanide concentrations greater than 0.1 mg/l are expected to kill sensitive species in freshwater or marine environments (Doudoroff, 1976;

Jan 1, 1988

By J. J. Crowhurst

The modem open pit-heap leach operation by Pegasus Gold Ltd. at Zortman and Landusky in Phillips County, Montana, is a new chapter in the mining of gold in these districts. The discovery of bulk tonnage ore bodies and their development and ultimate production was based on a long history of mining and exploration in that part of Montana. Gold was originally discovered in the Little Rocky Mountains as placer deposits by Pike Landusky and Lou Myers. This discovery in the 1880s was not significant, but Pike Landusky continued prospecting for lode deposits, and he eventually located the Gold Bug and Little Ben, two of the larger Au-Ag producers in the district. Eventually two camps, Landusky and Zortman, grew in the LittleRocky Mountains. By the time Landusky was killed in 1894 by Kid Curry, the district was still a discontinuous small producer. Steady production commenced in 1907 with the organization of the August Gold Mining Co. Eventually high grade ores on specific veins were exhausted by selective underground mining and the district was idle by May 1942. After World War II in the early 1950s. E.A. Scholz tried to continue selective underground mining, but he realized the stockworks surrounding the larger veins constituted bulk tonnage targets. Ultimately in the 1976- 1979 period he organized two exploration efforts, one each for the Landusky and Zortman areas, and brought these into production as the Argo and Pegasus gold mines. By the time of his death, Apr. 8, 1980, both operations were producing gold. Later the two companies were merged as Pegasus Gold Ltd. Upon the death of Scholz, V.F. Hollister continued as the geological consultant, Ed Roper was engaged as general manager, and J. J. Crowhurst was given the responsibility of executive vice president. The discovery of open pittable ores and the application of heap leach technology was important in the development of mining. Both contributed to the low cost operation that continues to this day. The attached article by L.M. Rogers, then chief geologist, and M.S. Enders, his assistant, describes the geology of the deposit. It was presented at the Northwest Mining Association meeting in 1982.

Jan 1, 1990

By Z. Kowalski

In the non-operational ?Górka? quarry, there are situated both a waste disposal site of an area of 6.7 ha, containing approximately 1 million ton wastes from high aluminium content materials (incl. about 400000 t of wastes from aluminum hydroxide production), and a pond of an area of roughly 3 ha, up to 15 m deep, with about 400000 m3 of polluted water and infiltrates from the disposal site mentioned. The basic problem related to the effluents in the Górka pond is both their high alkalinity (pH 12-13.4) and a variable analysis of pollutants whose level increases appreciably with the pond?s depth. The solution offered provides, first of all, remedial pumping and a treatment of effluents retained in the Górka reservoir. Effluents would be treated in a reverse osmosis plant according to a process verified so far on a quarter-commercial scale. The treatment process by-product, a brine solution (containing about 25% NaCl) whose amount may reach up to 100000 m3 might be supplied to the Debiensko Mine, which produces technological salt from salt-bearing mine waters. In parallel, an intake of underflows of infiltrates would be provided (previous geochemical identification) in order to take them away from the high aluminum site (by means of deep wells, and possibly girdling ditches). Such effluents would be subject to treatment. The successive stage is the utilization of approx. 50000 m3 of bottom slurry, left in the emptied reservoir, in the production of self-solidifying mixtures, which would be then used for sealing the bottom and the banks of the Górka reservoir. The empty and sealed reservoir would be filled up with a volume of approx. 600000 t of ashes, coming from coal burning in the thermal-electric power station. For the last stage, instead, is scheduled the rehabilitation of the entire waste disposal site in the Górka quarry. The site will be drained, covered with a leveling, sealing and rehabilitating layer, which will allow to introduce plants on the rehabilitated waste site. Later on, the area could be turned into a town park

Jan 1, 2006

By V. E. Gall, A. Vonthron, J. Ninic, A. Marwan, M. König, G. Meschke, A. Alsahly

"In current tunneling practice, finite element simulations have become an integral element of the planning and design process. These models are most often manually generated using 2D CAD drawings, which is a laborious and time consuming process. In this paper, we propose a BIM based approach, in which the 3D FE-model is automatically generated through a set of compatible geometries of individual components, i.e. the geology, alignment, lining and the TBM. The BIM model also includes all relevant model parameters of the tunneling project that can then be incorporated into subsequent analysis to be performed during the tunnel drive. The setup and the execution of the FE-analysis are performed automatically utilizing all required data from BIM. The applicability and efficiency of the proposed strategies is demonstrated by means of project data from the Wehrhahn-line metro project in Düsseldorf, Germany. Both the design as well as the construction stage is considered. INTRODUCTIONIt is recommend to employ Finite Element (FE) simulations in order to ensure a high degree of safety and quality for any given project (Guglielmetti et al. 2012). As such, FE models form an integral part in the design and planning stages of modern tunneling projects. These models are often time consuming to construct and require data from many different sources. This data is most often not centrally stored and therefore not easily accessible. Additionally, the formats in which project data are stored are typically not compatible with the formats required by an FE program. This is especially true in the case of geometrical data, such as CAD drawings. Although existing design drawings are most often used as the basis for a FE model, a direct import into a FE program is most often not successful as the imported data generates a geometry that does not fulfill the requirements of a FEM model, such as model connectivity. Even if a geometry is successfully imported, other necessary aspects of an FE model, such as boundary conditions and material properties, must be applied manually. These incompatibilities inevitably result in the creation of a new model, which, especially in the case of complex 3D models, is a time consuming process."

Jan 1, 2016

By Edmund W. Murphy

At the first workshop on Surface Subsidence Due to Underground Mining (1 981 ) , Yarbrough delivered a paper (1 ) describing the mine subsidence insurance program in Illinois operated as the Illinois Mine Subsidence Insurance Fund (IMSIF) . In this paper we will present claims data and describe changes that have occurred in the Illinois Insurance Code during the first six years the IMSIF has been in existence. The change in the original Illinois Public Act 80-1 41 3 that most affected the public was an amendment increasing the maximum amount of mine subsidence insurance avail- able on a structure from $50,000 to $100,000. Seventy-two counties in Illinois have been undermined for minerals, primarily bituminous coal. In Franklin County (.in the southern part of the state) 36 percent of the land area has been undermined for coal extraction. In St. Clair and Madison Counties , two counties that include the St. Louis Metropolitan area along the western border of the state, 10 percent and 7 percent of the land surface have been undermined. Most of the undermined area in the two counties is beneath urbanized land. In 34 counties, approximately 1 percent or more of the land surface has been undermined (2). The first shaft mine in Illinois was sunk in the city of Belleville (east of St. Louis) in 1842, and the mines of early vintage have initiated the majority of the mine subsidence claims. Data compiled from the first six years reveals that most Illinois mine subsidence events that affect structures occur over abandoned mines where early methods of high- extraction mining practices were used. Maps of these mines operated in the 1800s reveal irregular development of room and pillar areas and poorly defined production areas (panels). Rooms in the mines varied from 15 to 40 feet in width and the pillars varied in width from 5 to 40 feet. The pillars were often long and narrow. Recovery rates in mines that operated prior to 1900 generally averaged 50 per- cent, and extraction rates as high as 80 percent have been documented (2). Some pillar robbing occurred.

Jan 1, 1986

By W. M. Ma, Daniel W. H. Su, K. Centofanti, Yi Luo, W. L. Zhong, Syd S. Peng

5.1 INTRODUCTION There are several types of surface ground disturbances, each of which is immediately transmitted to surface structures and causes damage of various forms, depending on the location of the structures in the subsidence basin. Many criteria have also been proposed for defining the potential structural damage. All of these topics will be discussed in this chapter. 5.2 TYPES OF GROUND DAMAGES There are two types of ground damage, continuous and dis¬continuous, that could inflict damages to surface structures. Dis¬continuous ground damage is open fractures of various degrees. Four types of fractures are commonly seen (Brauner, 1973b): 1. Fissures or cracks. Cracks are the most common form of ground damage and range from completely closed to several feet wide. Surface cracks are most prominent when the ratio of mining depth to mining height is smaller than 30 to 50 times mining height. Cracks initiate parallel to, but ahead of the moving long¬wall face at some intervals when the depth-to-mining height ratio is less than 25 to 30. As the face continues to move, they open up and then close gradually, and in most cases eventually close up completely when the face moves farther away. Sometimes when the depth-to-mining height ratio is larger, cracks may initiate be¬hind the face and go through the same cycle. Cracks are also more likely to occur in the hill when the face is moving in the uphill direction. Cracks also occur at or near both sides of the panel edges. Those cracks tend to remain open permanently. When the surface is covered with grass or other vegetation, cracks of less than 1 to 2 in. wide usually do not penetrate it and become invisible on the surface. 2. Steps. A step may occur when the longwall face stops abruptly if the mining depth-to-mining height ratio is less than 20. Steps may also occur along the panel edges. Steps also range from a few inches to a few feet in width and depth. If planes of weakness are oriented favorably, ground will slide along these planes and form steps on the surface. 3. Cave-in pits. These result from local collapse of the ground from the mine level to the surface when the mining depth is less than 150 ft and occur mostly above abandoned mined lands. They may be as large as 40 ft wide and deep. 4. Bumps (compression ridges). Bumps result from ground compression and occur mostly near panel center some time after mining. Bumps of up to 4 ft, but mostly 1 to 2 ft, have been identified. Continuous ground damage refers to the formation of the sub¬sidence basin where continuous nondestructive ground deforma¬tions occur. As mentioned earlier, continuous ground deforma¬tions associated with a subsidence basin include subsidence, slope, curvature, displacement, horizontal strain, twisting, and shearing. 5.3 TYPES OF SURFACE STRUCTURAL DAMAGES Both continuous and discontinuous ground disturbance cause damage to surface structures. A. Structural Damages Due to Discontinuous Ground Disturbance 1. Fissures or cracks. Open cracks can cause dislocation of surface structure if the gaps are sufficiently large so that the struc¬tural elements cannot resist but fail. On the other hand, minor cracks affect only the appearance, and not the structural integrity. 2. Steps. When a surface structure is located on a step, some portions of the structure lose support and become overhung. In the case of a residential house, there will likely be many open frac¬tures in the overhung portions, followed in severe cases by sepa¬ration of the superstructure at the edge of the step. 3. Cave-in pits. If the caved-in pit is larger than the surface structure, the structure will drop into the pit and become unstable. If the caved-in pit is smaller than the surface structure, the struc¬ture may either become overhung or lose support in some portions. In either case, it is unsafe for use. 4. Bumps (compression ridges). Bumps will disrupt roadways or house floor. If located under supporting members of the struc¬tures, it may cause damages. B. Structural Damage Due to Continuous Ground Disturbances 1. Subsidence. Pure subsidence or uniform subsidence over an area does not cause any structural damage. However, if it becomes a topographical low area, it may be flooded with water and make the surface structures unusable. It must be noted that the flat bottom area at the center of the final supercritical subsidence basin does not reach that position suddenly. Rather, as shown in Fig. 3.1, it is subjected to the dynamic surface deformation asso¬ciated with the traveling subsidence basin before it is left behind to be part of the flat-bottom area. Therefore any structure located at the center of the final supercritical subsidence basin must be able to resist the dynamic surface deformation in order not to be dam¬aged. 2. Slope. Ground slope will induce tilting of the structure. Tall structures with small base areas, such as water towers, chimneys, and power transmission towers are most sensitive to ground slope. If the ground slope is such that if after tilting the center of the gravity of the tilted structure falls outside the base area, it will topple, but this seldom occurs. Ground slope will change the designed slope of a buried trans¬portation pipeline, either increasing or decreasing the original slope depending on whether the ground slope coincides with or opposes the original slope. There are maximum allowable final slopes for various types of transporting materials. Ground slope also affects highways and railways. There is a maximum allowable final slope for a railway because tractive effort increases 1/1000 of its weight for every increase of 1/1000 in grade. 3. Curvature. There are positive (convex) and negative (con¬cave) curvatures. When a surface structure is located on a positive curvature, both ends become unsupported, followed by bending upward at the midportion. The top portion is subjected to more severe stretching than the lower one. As a result, vertical cracks with a wider gap at the top occur at the window, door frames, on the walls, and at -the wall joints. V-shaped cracks appear at the

Jan 1, 1992

By R. Bhaskar

An airborne dust cloud is an ensemble of particles of varied size, density, shape and states of aggregation. An understanding and quantifying of the dispersion and deposition of the dust generated in mines is essential to the development of measures for reducing worker exposure to dust. In coal mining, the major portion of the dust is generated during the cutting of coal using either a shearer or a continuous miner. The major phenomenon affecting ambient concentration is the deposition of dust. Particle deposition may take place due to the effect of gravitational, inertial, electrostatic, and thermal forces, and mechanisms such as Brownian and eddy diffusion, and inertial impaction. The three major mechanisms of deposition in turbulent flow in mines are diffusion (Brownian and eddy), sedimentation and inertial impaction. The mechanisms determining particle deposition are size dependent.

Jan 1, 1990

By D. R. Spears

As part of its mission to develop technology to assure a continuing supply of minerals, the US Bureau of Mines has investigated the flocculation of a Stillwater, MT, chromite ore. The ore was flocculated at different solids contents and at different stirring speeds to determine the importance and effect of hydrodynamic factors. In acidic and basic pH, the chromite ore was flocculated with high molecular weight polyacrylamides differing in the degree of hydrolysis. Polyacrylamides were found to bind to chromite ore particles through hydrogen bonding. The anionicity of the polymer and the pH affected the degree of polymer-particle interaction, which in turn affected polymer conformation at the surface. A polymer conformation with many loops and tails was used to explain high flocculation efficiency. It was found that such a conformation could compensate for poor hydrodynamic conditions.

Jan 1, 1992

By J. M. Mutmansky

This paper outlines patterns of methane emission in both longwall and room-and-pillar operations and the effects that these patterns have on the decision as to whether the methane is most economically handled by ventilation alone or by means of a methane drainage system in addition to ventilation. The costs of handling the methane in the ventilation system and the costs of implementing the methane drainage system will be discussed as well as the costs related to the production of coal. The important issue of production slowdowns and gas outs will also be discussed as well as the proper response of mine management to such a situation. Suggestions concerning the keeping of production records related to methane problems will be made as well as justification for more intensive economic analysis of coalbed methane extraction and utilization.

Jan 1, 1998

By M. N. Herrera

The bioleaching of mineral sulfide pulps in a bench-scale rotating drum reactor has been studied. The reactor includes horizontal paddles in the inner wall for lifting of the mineral pulp. The performance of the reactor was tested in the bioleaching of a refractory pyritic gold concentrate in the presence of pure Thiobacillus ferrooxidans strain (ATCC 19859). The concentrate was efficiently bioleached at 50% pulp density with the drum operating at 0.5 -1.0 rpm Attempts of bioleaching the concentrate at the same pulp density in conventional stirred reactor showed severe inhibition of bacterial activity. The results demonstrated that the drum reactor allows to operate at much higher pulp densities than the conventional stirred tank reactor. This behavior is explained in terms of an improvement of the bacterial activity due to a better control of the attrition of the mineral particles.

Jan 1, 1997

By K. O. Johnson

Contaminant transport of mine and mill tailings is controlled by the hydrologic flow regime and the geochemical mobility of the contaminants. Contaminant&apos; mobility is primarily determined by chemical reactions occurring within an interface zone between the tailings and soil The large geochemical differences between tailings and groundwater create a disequilibrium in the groundwater with respect to the soils when seepage from tailings enters the groundwater. Precipitation and dissolution reactions involving the major chemistry occur to return the perturbed system to chemical equilibrium between groundwater and minerals. Retardation of trace elements depends upon the chemical character of the groundwater and the adsorption substrates. In the case of uranium mill tailings, the mobility of contaminants is controlled primarily by precipitation/dissolution reactions which neutralize the pH, modify the Eh (redox potential), and produce highly adsorptive substrate for retardation of trace elements.

Jan 1, 1988

By Duk-Won Park

Ground water has been a problem in underground mines (Anon., 1981; Aughenbough, 1973; Stansbury, 1981). Water migrates from water-bearing formations and surface water bodies such as lakes, ponds or creeks into the underground workings through fractures and cracks. As a result, under- ground workings become plagued with the necessity of having the water pumped out in large quantities. Underground workings become flooded when unexpected amounts of water flow into the openings, especially when mines use pillar extraction or longwall mining methods. It is difficult to detect water bodies above the coal mine roof before water problems take place. The resistivity method was used as a method for detecting water saturated rock layers and bodies of water above the roof of a coal mine in northern West Virginia, where the multiple seam mining method was being used.

Jan 1, 1983

By L. D. Cruz

In Exxon&apos;s Los Bronces Expansion Project in Chile, a stochastic simulation is performed to resolve the complex decision problem of matching the mine to mill system capacities from both technical and economic standpoints. The unique combination of weather conditions at the mine and the 30-km belt conveyor network for ore transport to the mill necessitates this analysis in the planning phase to optimize the design capacity of the sys tem. Appropriate statistical distributions of major equipment performance, snow storm duration, power outage, etc, ate developed from actual mine local records and manufacturers specifications. The interactions of operational constraints including ore storage capacities, number and sizes of individual equipment, ore variations, and mine and mill production rates are studied more realistically than in a traditional planning approach. Details of the computer modeling and typical results of simulation studies are discussed.

Jan 1, 1981

By G. H. Matthes

Many mines, in particular coal mines, use inclines or slopes as an access to seam or seamlike deposits which outcrop at or close to the surface. In general, from the surface or from a certain depth, inclines or slopes follow the dip of the deposit with length up to 30,000 feet and by that going under an overburden cover of several thousand feet. The common outbye transport system for mine products is the conveyor. Material and men to be transported down into the mine are handled by rope driven systems when the angle of inclination exceeds the employment of locomotive traction. The transport volume can be sizeable and reach 200 to 300 tons of material and 500 men to be handled daily in a medium size coal mine with a production of 10,000 tons ROM.

Jan 1, 1986

By George A. Desborough

Marine black shales of Paleozoic age in the Western United States that exceed 10 weight percent organic carbon contain as much as 5,000 ppm vanadium, 1,000 ppm molybdenum, 1,300 ppm nickel, 600 ppm cobalt, 16 ppm silver, 7,000 ppm chromium, 18,000 ppm zinc, 280 ppm cadmium, and 350 ppm selenium. Depositional settings include: (1) continental-rise and marginal-ocean basins, (2) continental-shelf and foreland basins, and (3) cratonic-platform embayments. Most of these metalliferous organic-rich shales have not been examined for resources because of rapid weathering and poor exposures which preclude easy sampling of unoxidized rock necessary to determine actual concentration and residence of indigenous metals. Generally, the marine black shales of Paleozoic age in the Western United States are richer in metals than marine Paleozoic black shales in the Eastern United States.

Jan 1, 1982

By James H. Nulty, Joseph S. Roti

Wetting agents used for heap leach gold applications would appear to have technical merit in aiding in recovering higher levels of precious metal. Many questions, however, remain as to whether they will function in practice, on what type of ore are they effective and if there are any negative affects associated with their use. A series of experiments are conducted at Bateman Labs, Sparks, Nevada, to determine under what conditions reagents of this type are useful. Carbon kinetics test work was also performed to determine if there are negative aspects associated with carbon loading with the use of these treatment chemicals. This paper outlines the results of these research evaluations, the general chemistry associated with action of wetting agents on leach ores and future work which is planned to further determine the viability of these products in the mining industry.

Jan 1, 1998

By C. L. Sarff

[Automation has become a word that means many things. To management it is the end of the rainbow; you push a button and all your problems are solved. To the working man it is a horrible monster that is taking his livelihood away. To the maintenance man it is a complex that overwhelms him when he thinks of trying to find the trouble when the machine is not operating, properly. Automation has been with us in the coal nines for many years. Long before my time you were using float switches on mine sumps to control the level of the water. That?s automation in the truest sense of the word, but we call it automatic and think nothing of it. If we use the word automatic instead of automation your mine electrician and mechanic will take hold of the problems in stride.]

Jan 1, 1962