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By W. C. Shanks

Metalliferous sediments and/or saline brines have now been discovered in numerous sea floor deeps along 900 km of the axial rift zone of the Red Sea (Fig. 1). The Atlantis II Deep remains the most interesting of the the brine deeps both in terms of intensity of submarine hydrothermal processes and in terms of potential economic importance. In fact, successful completion of a pre-pilot mining test in 1979 indicates that the Atlantis II Deep may become the first deep sea base metal sulfide mine (Mustafa and Amann, 1980). Under the most optimistic scenario, the Atlantis II Mine might be established 4-6 years after completion of a year long pilot mining test in 1983-84. If established, mining would produce about 100,000 tons per day of wet mud with about 200 tons per day contained zinc, and proportional amounts of Cu and Ag. Expected mine life would be about 15-20 years (Anon., 1981). In addition to direct economic importance, the Red Sea brines and metalliferous deposits provide significant insight into exploration for sea floor brine-related ore deposits and for analogous ancient deposits. In this paper I will concentrate on the economic potential of Red Sea deposits and sea floor exploration for brine related deposits, but some ramifications of relevance to ancient deposits are extant.

Jan 1, 1982

By William J. Shampine

The Floridan aquifer, which underlies all of Florida, yields water with a hardness of less than 180 pmts per million (ppm) in the northwestern part and throughout much of the center of the Slate. In most of the rest of the Stale, the aquifer yields water having a hardness greater than 180 ppm and as much is 1,900 ppm. Hardness of ground water is caused by dissolved salts from the geologic formations through which the water passes or by direct pollution. Sometimes pollution may indirectly increase the hardness of ground water by increasing the acid content and thus increasing the solution of calcium and magnesium salts. Water from deep zones of the aquifer lend to he harder than water from more shallow zones. Only the hardness of water from the upper part of the aquifer is shown.

Jan 1, 1966

By J. W. Mustard

The Macmillan Pass tungsten property (MacTung) is the largest known copper-tungsten, calcic, exoskarn deposit in the Western Hemisphere. Located on the border between the Yukon and Northwest Territories in northwestern Canada, the deposit crops out on Mt. Allen within the Selwyn Mountain Range. It was discovered in 1962 by a subsidiary of AMAX Inc. and has since been explored by 16,300 meters of surface and underground diamond drilling and by 800 meters of underground development. Geologic reserves are in excess of 30 million tons, grading slightly less than 1.0% WO3. Scheelite (CaWO3 ) is the main mineral of economic interest. Accessible by road, the property is not in production. Previously estimated reserves at MacTung have been unable to fully utilize all the geological controls on mineralization. In the past three years, however, an intensive program has been underway to improve our understanding of the deposit and to use the resulting information in a more precise way. This paper will discuss the key aspects of the geology as they specifically relate to reserve estimation and will demonstrate how these controls are being used in a geostatistical model of the deposit.

Jan 1, 1985

By P. L. Dunn, G. T. Adel, E. B. Cruz

Automatic control of fine-coal cleaning circuits has traditionally been limited by a lack of adequate sensors. Although several nuclear-based analyzers are available, none have seen widespread acceptance. In this investigation, image analysis is used for the on-line determination of ash contents in fine-coal slurries. The ash content of a flotation tailings stream is correlated to the mean gray level of the slurry. Based on a 90% prediction interval, an analysis of sensor performance indicates an accuracy of 73[±] 4% ash over a range of from 65% to 90% ash. While the results are comparable, the video-based system costs only a fraction of what a nuclear-based analyzer costs. The sensor is now installed at the Middle Fork preparation plant, which is owned by Pittston Coal Co.

Jan 1, 1999

By T. Carageorgos

The removal of arsenic from process streams as ferric arsenate compounds is being practised by mining industries. Therefore, the solubility and stability of these solids is of considerable importance to the mining plants that have to keep the environment free from pollutants. There is some information on the solubility of the ferric arsenate compounds, mainly on scorodite, obtained from synthetic solution. However, there is not so much work on ferric arsenate compounds formed at high temperatures (175 - 230°C) during the leaching process. In the present work, the solubility of the ferric arsenate compounds formed during acidic pressure oxidation of arsenopyrite is presented. The results of the solubility tests showed that the ferric arsenate compounds formed at high temperatures (200 - 230°C) and high pressures (1034 - 1551 kPa 0,) released arsenic into solution in amounts less than 1.2 ppm and iron in amounts no higher than 1.0 ppm. So, they seem to be potential compounds for arsenic and iron disposal.

Jan 1, 1998

By R. L. Bleifuss, S. Zhong, H. E. Geotzman

Microwave heating of iron ore was investigated as an alternative to conventional reduction processes to solve the problem of slow heat transfer. Microwave heating and reduction tests were run on composite green balls made from coal and magnetite concentrate. Benchscale tests were run on both powdered and pelletized feeds using a 15 kW microwave generator. A significant increase in the reduction rate was obtained. With 20% excess stoichiometric carbon in the mix, more than 90% reduction of the iron ore can be achieved in about 10 min at temperatures of around 1,000°C. The reduction of iron ore with coal by microwave heating produces a pure, dust free, high-Btu flue gas that can be used in related thermal operations. Depending on the purity, the reduced iron product could be fed directly to an electric arc furnace for melting. In some cases, the removal of a slag phase may be required to eliminate excess silica and alumina.

Jan 1, 1997

By Joseph Cervik, Fred Garcia

Gob holes are routinely used by the mining industry to vent methane from gobs and to prevent it from entering the mine ventilation system. In some cases, flows from gob holes are measured by centering an anemometer on the end of the discharge pipe. These measurements are erroneous and tend to be high by as much as 30%. The Bureau of Mines determined correction factors (method factors) for anemometer measurements taken in this manner. Method factors for 10.2, 15.2, and 20.3 cm (4, 6, and 8 in) ID pipe are 0.68, 0.71, and 0.78, respectively. Comparisons between horizontal and vertical flows indicated no significant change in method factors. Consequently, the method factors for horizontal pipe flows can be applied to vertical upward flows.

Jan 1, 1987

By K. N. Han, Q. Xu

The adsorption behavior of gold in ammoniacal solutions on activated carbon was studied. The gold adsorption capacity of the activated carbon and the recovery efficiency were examined. The parameters affecting the adsorption of gold on the activated carbon included temperature, agitation speed, the concentration of cation and anion and the concentration of ammonia. It was found that the maximum gold adsorption was about 10 kg/t of carbon. The recovery of gold by the adsorption, from ammoniacal solutions was found to be dependent upon the initial gold concentration. Under experimental conditions, a gold recovery of 98% was obtained after 120 hrs of adsorption. It was also found that the initial adsorption rate was relatively fast, when compared to the entire adsorption period. The apparent activation energy for the adsorption was determined to be 15.8 kJ/mol. It was believed that the kinetics of gold adsorption on the activated carbon was controlled by pore diffusion.

Jan 1, 1997

By D. Triantis

This paper presents the results of laboratory experiments for the detection of electric signals from Fiber Reinforced Polymer (FRP) sheet samples which have undergone a temporally increasing loading of bending type up to fracture. Electric signals that were recorded while the sample was subjected to bending are referred from now on as Bending Stimulated Currents (BSC), in order to differentiate them from the relevant signals emitted by materials that suffer uniaxial compressional stress. The latter signals are referenced as Pressure Stimulated Currents (PSC). BSC emitted from FRP sheet samples presented here, were recorded after applying three successive load steps to samples. The increase rate of applied stress was about 0.15kN/s. Initially starting from low load values to higher load values until the FRP sheet reaches at a state just before its failure. The BSC records from FRP samples are compared to equivalent recordings from cement mortar beam and distinguishable differences are discussed.

Jan 1, 2006

By Justus B. Deen

Given that the majority of mine ventilation operating costs are imposed by shafts, the need to predict the resistance of a planned shaft with reasonable accuracy is important. During conceptual design, shaft resistances are usually predicted by use of published friction factors, k, based upon lining and fitting configurations. More often than not, published friction factors do not directly coincide with "real" shafts, so their use is somewhat limited. For more accurate shaft resistance determination, equations both theoretical and empirical may be employed if there is detailed knowledge of the shaft. These equations treat the shaft resistance as discrete components, with their sum being the overall shaft resistance. This paper describes the basic shaft resistance equations and verifies these equations by comparison to field measured shaft resistances. Several shafts were examined which varied in depth, shape and fitting arrangements. Results are presented and conclusions drawn to show that the shaft resistance equations are accurate.

Jan 1, 1991

By George C. Trevorrow

It is a pleasure to appear on this program and discuss a subject which is of particular interest to me. In my regular duties as Safety Director of Bituminous Coal Operators' Association, I am called on by member companies to discuss matters affecting face ventilation. As a member of the Joint Industry Safety Committee, as I will later describe, I have a part in processing requests for the use of auxiliary fans for face ventilation. The use of auxiliary fans in bituminous coal mines for this purpose came into rather wide use in the late. '20's when conveyor mining was introduced. In this application, the equipment consisted of a chain conveyor with a face chain conveyor parallel to the face on which the coal was loaded by hand and, in turn, was discharged onto the room conveyor and thence to a loading point on the entry at the mouth of the room. Another method was to use a shaker conveyor with a duckbill which was maneuvered across the face of the room from which the coal was loaded and transported by the shaker to the loading point. In either case the equipment did not readily lend itself to driving crosscuts or breakthroughs with the result that rooms were driven to depths of 250 or 300 feet without adequate means of ventilating the face area with the main split of air. It was, therefore, necessary to use other means of ventilating this area as the rooms were being driven and during retreat work if pillars were extracted. Auxiliary fans of the blowing type were utilized for this purpose. They were of very small capacity using small diameter tubing. By the time the room was driven half way to its projected limit ventilation was very poor or practically nonexistent. To compound the problem the fan was usually set up at the mouth or neck of the room and in many cases the intake air to the fan was the return air from the room. It is small wonder, therefore, that there is on record 12 cases where auxiliary fans were given as the cause of explosions. In 9 of these occurrences, arcs or sparks from open-type motors or accessory equipment on these fans were given as the primary ignition source. They fell into such ill repute that in a number of cases they were blamed as the ignition source even though smoking was strongly suspected as the primary cause.

Jan 1, 1967

By Bjørn Nilsen

"INTRODUCTION/BACKGROUND Weakness zones or faults containing clay-rich gouge represent one of the most challenging rock mass conditions to be encountered during tunneling. In Norway, such conditions count for a large part of the rock support costs, and in cases where the rock support has been insufficient, serious instability and cave-in have in many cases been the result. Most commonly, such cave-in has occurred after water filling of hydropower tunnels, but in some cases it has also occurred in tunnels under excavation and in completed “dry” tunnels. To avoid instability, two important requirements have to be fulfilled: 1) The location of the weakness zone and its character have to be identified in time. 2) The rock support has to be sufficient to withstand the loading caused by the zone. An incident which really brought the problems related to swelling clay into focus was the cave-in at the Hanekleiv road tunnel in 2006. Here, rock fall from the roof as shown in Figure 1 occurred unexpectedly about 10 years after the tunnel was completed. Fortunately this happened at a time with very little traffic, and nobody was injured. This incident emphasized the significance of the issue of swelling clay, although it was found to be caused also by gravitational collapse of the clay-rich gouge material of the weakness zone, and not related to swelling only (Nilsen et al. 2007).In this paper, main focus will be on discussing the characteristic features of swelling clay, test procedures which are being used for characterizing swelling clay, and the reliability of the results from testing for use in support evaluation and design in conditions with swelling clay. It is generally well known that swelling clay may cause considerable pressure on support elements, but quantifying this pressure for reliable analysis and design of rock support is still a great challenge."

Jan 1, 2016

Researchers at National Institute for Occupational Safety and Health (NIOSH) are investigating how fiber-reinforced shotcrete mix designs can be extrapolated from proven designs employing wire mesh. This paper explains the results of round determinate panel tests and relates the flexural strength and toughness of fiber-reinforced shotcrete to known energy absorbing properties of wire mesh. The energy absorbed with central deflection is strongly influenced by the amount of fibres. The higher the energy absorption the more load cracked shotcrete can support. Two types of fiber-reinforced shotcrete were investigated, one with steel fiber and another with polyfiber. The residual load supported in Round Determinate Panel Tests can be matched with the strength of wire mesh, thus providing equivalent bag strength values for fiber reinforced shotcrete panels. There is also evidence of a panel crack width comparison to the load holding capabilities of the fiber in the shotcrete mixes. In practice, this provides designers with a method for comparing the ground support provided by fiber-reinforced shotcrete with that supplied by wire mesh.

Jan 1, 2010

By M. K. Buder

Over the years, electric utilities have been faced with declining steam-coal quality, rising coal prices, and increasingly rigid and costly environmental standards. As a result, many utilities are beginning to show an interest in coal cleaning to upgrade coal by improving its heating value and reducing its sulfur content. Among the primary questions that must be answered for these electric utilities is whether the cost of coal cleaning can be offset by the potential cost savings in coal transportation and utilization in power generation. In search of at least a preliminary answer to this question, the Electric Power Research Institute (EPRI) engaged Bechtel to perform a case-by-case economic study to examine the cost effects of using cleaned versus raw coal to fuel new electric power plants. The results of two of the seven cases studied which involved western coals - one from Montana and another from Utah - are reported in this paper. Coal cleaning appeared to be a cost effective option for the Utah coal, but only marginally economical for the Montana coal. These cost results are expected to change to favor coal cleaning to a greater extent with the application of the final revised New Source Performance Standards regulating SO2 emissions just issued by the EPA. The study was based on the regulation originally proposed by the EPA under the 1977 Clean Air Act Amendments.

Jan 1, 1979

By K. M. Atencio, T. Pike, S. Forrest

We will introduce the Small Business Liability Relief and Brownfields Revitalization Act, which is an amendment to CERCLA and the types of sites it includes and excludes, especially as related to mine-scarred land. We will also describe the types of available funds, whether they are competitive or not, what entities are eligible to receive them, and how to access them. We will introduce the legislation’s liability provisions; for example, the recently issued interim guidance clarifying some of the conditions that contiguous property owners, bona fide prospective purchasers, or innocent landowners must meet to qualify for the liability limitations provided in the Brownfields Law.

Jan 1, 2004

By Norman F. Sweeney, H. John Hovland

Over one million yards of granite were excavated for the Helms Pumped Storage Project, including a large underground powerhouse complex. Site investigations and in situ stress measurements were essential elements of the project design and provided the necessary geologic parameters for executing a finite element study of the powerhouse. A construction monitoring program, of geologic mapping, field instrumentation, and rock mechanics testing was then designed and has been successfully implemented. This paper reports on the scope of this construction monitoring program and explicitly compares the measured deformations to those predicted. As a result of this recent field experience the assumptions used in the finite element program are reexamined.

Jan 1, 1981

By K. T. Valsaraj, L. J. Thibodeaux

Solvent sublation, the separation process for the removal of two hydrophobic compounds (penta- and trichlorophenols) from the aqueous phase, is discussed, as is a steady-state mathematical model for fire process. Solvent Sublation "'as conducted in a continuous countercurrent mode. The underlying mechanisms, theory and experimental details on the effects of process variables on removal efficiency are reported.

Jan 1, 1994

By M. J. Liesveld, D. Liesveld

For a Colorado mountain quarry, the Water Jet Channeling Method is far superior to Burning, Sawing, Drilling, or Shooting with Primer Cord, Water, or Black Powder. Throughout the life of our quarry, which was founded in 1947, we have used all the methods and turned to the Water Jet Channeler, which we invented and patented as our ideal way to remove dimension granite from our quarry. We jet the block on 4 sides and remove the block with plugs and feathers on the backside. The Water Jet uses approx 7.5 l/m (2 gpm) running at310,000 kPa (45,000 psi) to erode the crystals @ 1sm/h (10sf/h).The 0.533mm (.021”) nozzle oscillates back and forth to achieve an approx 5cm (2”) channel. Using the Jet, we do not lose corners or cause cracks in our red fine grain light class 5 granite.

Jan 1, 2004

By S. -H. Kim

This work investigated the effect of the concentration of CO2 and lead contamination on the forest ecosystem. Changes of the plant growth, lead concentration in soil, plant, and soil microbial community caused by CO2 concentration (380 ppm and 760 ppm) and lead contamination (500 mg/kg) were measured. Plant growth was inhibited by 50% due to lead contamination. Particularly, shoot growth was inhibited more than the root. However, the root elongation was not affected by the CO2 concentration increase. The diversity of microbial population with AWCD (Average Well Color Development) and PCA (Principle Component Analysis) showed that the lead contamination has an effect com-pared to CO2 concentration. The Shannon index calculated from DGGE profiles was high in soil with Pinus densiflora, while the effect of CO2 concentration was not significant (P<0.5). The similarity of microbial community from each treatment showed that lead has an effect on plant growth and microbial community rather than the CO2 concentration.

Jan 1, 2006

By S. Veeramasuneni

The recent nonequilibrium electrophoretic mobility measurements by laser-Doppler electrophoresis coupled with the stability and prevalence of collector colloids in soluble-salt flotation systems suggest that the selective flotation of alkali halides is due to the adsorption of oppositely charged collector colloids by heterocoagulation. Previously reported flotation results confirm this surface charge/collector colloid adsorption model. These results also indicate that the sign of the surface charge has a significant effect on the extent of particle dispersion/aggregation. In this regard, the nature of such particle interaction forces at high ionic strengths are examined to improve our understanding of these systems. Atomic force microscopy (AFM) is now being used to directly measure the interaction forces responsible for the stability of these alkali halide aggregates observed in optical microscopy studies. Results from this study indicate that, while repulsive hydration forces exist between similarly charged hydrophilic particles, attractive forces exist between oppositely charged hydrophilic particles in high ionic strength solutions.

Jan 1, 1999