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By Luigi P. Gonano, John C. Sharp

The Drakensberg Pumped Storage Scheme in South Africa with an operating head of 500m is located in sedimentary rocks containing relatively weak argillaceous strata. The paper describes design and construction aspects of the high pressure concrete-lined tunnels, and the associated investigation techniques and construction controls.

Jan 1, 1983

By M. S. Vernon, J. J. Kellar, W. M. Cross, R. M. Winter, F. J. Johnson, A. G. Pommer

Three substrates (MgO crystal, CaF2 crystal and Mg plate) were used to construct thin layers of Mg(OH)2. Various routes were used to modify these substrates, including surface hydration and sol-gel coating. In each case, it was found (by using Fourier transform infrared spectroscopy) that thin layers of Mg(OH)2 could be produced. In the case of hydrated layers, the surface morphology of the Mg(OH)2 resembles the bulk platelet shape of precipitated Mg(OH)2.

Jan 1, 2000

By J. Shibata

Separation of rare earth, especially Nd and Sm, was investigated by batch and column methods with a solvent impregnated resin. The solvent impregnated resin was prepared by impregnation of organo- phosphorous extractant whose trade name was PC-88A into a macro porous resin. The adsorption behavior of rare earth with a solvent impregnated resin in a batch method is the same as that with solvent extraction. In a column method to separate Nd and Sm, the effective separation in both adsorption and elution processes can be attained by setting suitable conditions, such as bed height, flow rate and concentration of eluent. Neodymium which is a lighter rare earth is separated from Sm an adsorption step, while Sm in which is a heavier rare earth is recovered in an elution step. From the integration of breakthrough and elution curves, yield of Nd and Sm is calculated in the condition of 100% purity. It was found from the results of life test of the resin that the solvent impregnated resin can be repeatedly utilized at least 20 times.

Jan 1, 1995

By S. Slottee

The disposal of plant tailings in a safe and environmentally acceptable manner has taken on increased importance throughout the world, across all types of mineral beneficiation plants. In the U.S. plant life span, expansions and new plants in the current robust mineral markets are faced with environmental pressures to minimize the use of land for disposal by maximizing existing tailings pond capacity. The combination of many drivers from economic to environmental have brought paste thickeners into the coal industry (PasteThick 2007) Thickening tailings to a more concentrated slurry is a common step in the disposal flow sheet. Thickening to a non-settling ?paste?, also called ?thickened tails? or ?tailings stacking?, is a relatively recent development. This paper describes the paste thickener as an alternative for dewatering a fine coal refuse (tailings) stream for deposit as a paste. Initial operating results of the paste thickener are discussed.

Jan 1, 2008

By Y. C. Kim

One-quarter of a century has passed since the "theory of regionalized variables" (geostatistics) was introduced by G. Matheron (1962, 1963) in France. Yet, only during the past decade has geostatistics found broad acceptance in the mining industry. Foremost among the reasons for this time lag was ignorance. The first English treatise on geostatistics was not written until Matheron (1971), and the first published text accessible to mining professionals did not appear until David (1977). Other significant reasons for the slow acceptance of geostatistics included the conservative nature of management in the 1970s minerals industry, and the fact that conventional ore reserve estimation performs reasonably well when confined to massive deposits of base metal and iron deposits having relatively low coefficients of variation in grades. In short, mine engineers and geologists were not willing to accept a new set of tools for problems that they did not see.

Jan 1, 1989

By Paul M. Keyser, Donald G. Foot, Jeffrey D. Mckay

In the past 30 years, there have been tremendous advancements in the uses and applications of column flotation. From their first use as final cleaners that could produce excellent grades at the cost of recoveries, columns are now being used in every stage of the flotation circuit as well as is SX-EW. Columns as roughers, final scavengers and even at the end of CIL circuits, are finding their way into the marketplace. Operational results of these new uses are presented. INTRODUCTION Flotation columns have been in use since the early 1950's in the U.S. (Hollingsworth, 1952) and the early 1960's in Canada (Trembley, Boutin, Wheeler, 1963). Application of column flotation has been somewhat diverse. In the early years, columns were used predominately for molybdenum cleaning in Canada and for phosphate flotation in the United States. Unfortunately, results met with skepticism and disdain as the columns were hard to operate, temperamental and although producing high grades, could not achieve acceptable recoveries. Since the inception of column flotation technology, the degree of knowledge for design and operation of columns has vastly improved. Despite improvements in the technology, there is still some reluctance by mineral producers to investigate the use of column flotation cells for processing stages other than cleaner flotation. This characterization is in part due to the proven advantage of flotation columns in reducing gangue entrainment in the froth product which results in higher grade products and/or fewer processing stages. Also, during the development of column technology, different types of spargers have been used with varying degrees of success. Furthermore, the general knowledge base of parameters affecting column flotation design and operation have advanced tremendously. Inefficient, or primitive, sparger design, coupled with the lack of column design and operating knowledge and experience, resulted in poor metallurgical and mechanical performance in many cases. Unfortunately, this lack of knowledge caused many column installations to be characterized as failures. The industry felt that columns could not achieve high recoveries, especially when dealing with coarse particles. Therefore, columns were characterized as cleaners, where low recoveries could be tolerated as recirculating loads rather than direct losses and froth cleaning advantages of the quiescent column flotation regime could be realized. Fortunately for the minerals industry, some producers have stood at the forefront of technology and allowed the column to be utilized for new applications. In the last decade, column flotation applications have expanded to virtually every mineral system and plant location throughout the world. The expanded application of columns has generated a new wave of interest for processing various streams. One of the most notable is in the use of columns as rougher cells. This is of particular interest to "green-field" plants and plants where expansions are taking place. Here, metallurgical superiority can be combined with maximum capital and operating cost advantages for a rapid return on investment. The superior results experienced to date, have generated a cohesive vision of the future in mineral processing where flotation columns function as single stage primary separation devices (roughers) with a single stage cleaner, if necessary. The advantages of column flotation go far beyond their original uses. We now have seen columns used as final tail scavengers, in SX-EW plants and even at the end of CIL circuits. Some of these cases will be reviewed. CASE STUDIES In an attempt to show the diversification of column flotation to many facets of the mineral processing plant, a variety of case studies will be discussed. Some of these were designed by the authors while others have been provided by plant sources. It is important to note that in each successful case, the columns were designed using the author's design and scale-up approach. This method assures that the columns are designed correctly for their particular application. For successful

Jan 1, 1993

By F. F. Aplan

Estimations have been made of the tonnage of raw ores and coal treated by various beneficiation processes. The amount treated by gravity concentration is substantially greater than that treated by flotation, with coal representing the bulk of the material treated by gravity means. A discussion is given of the trends and anticipated improvements in gravity methods. Except for the concentration of iron ores, magnetic and elec- trostatic separation processes find their greatest use in the beneficiation of non-sulfide ores. Exciting new developments in magnetic materials and separation process (and, to a lesser extent, in the electrostatic process) indicate a substantial increase in the application of such processes to ores and a broad variety of non-ore uses.

Jan 1, 1989

By A. C. Noble, D. E. Ranta

Orebodies with intricate three-dimensional shapes (such as porphyry molybdenum deposits) are difficult to model using geostatistics or other computer-assisted methods. The strong trends in their spatial grade distributions occur as mathematically complex shapes and prevent the customary assumption of local stationarity that is required for accurate ore reserve estimation. "Zoned Kriging", a new method developed by AMAX, solves this problem directly by using the geologist's interpretation of the ore zones as a parameter in the kriging equations. The geological basis and methods used in the Climax ore zoning technique are reviewed and discussed relative to their application in zoned geostatistical modeling. The Zoned Kriging technique is described and demonstrated using data typical of mineral deposits.

Jan 1, 1992

By T. M. Ruff, W. G. McCoy, M. J. Beus, S. Iverson

Monitoring conveyance position and wire rope load directly from the skip or cage top offers several significant safety and production advantages. The Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) developed a shaft conveyance monitoring system (SCMS). This system consists of position and guide-displacement sensors, a maintenance-free battery power supply and a new sensor, which is mounted on the wire rope with a Crosby Clip, to measure hoist-rope tension. A radio data link transmits sensor output to the hoistroom. A state-of-the-art automated hoisting test facility was also constructed to test the concept in a controlled laboratory setting. Field tests in full-size shafts are now underway.

Jan 1, 2000

By Lawrence M. Lenahan

Cleveland's Southwest Interceptor Contracts No. 3 and No. 4 are continuations of Contract No. 1 addressed at the 1987 RETC with geology, equipment, and methods that differ greatly. The two contracts consist of 791 m (4.22 miles) of 3.5 m (11.5 ft) tunnel lined to 2.9 m (9.5 ft), nine access shafts, six drop shafts, and six collection structures. The excavation drive was completed by the use of a 1970 vintage Robbins TBM hybrid for this particular job through the use of both new and old technology. All other excavations were successfully accomplished through drill and blast method in tight residential areas. Concrete lining and connections were completed nine months after holing through.

Jan 1, 1989

By J. P. Nairn, C. M. McCulloch

More and more underground mining is being conducted using the long wall method. Likewise, many new surface mines use area or mountaintop removal methods. These methods can have a significant impact on surface and ground water resources. The overall study of the effects on surface and ground water from mining is referred to as the probable hydrologic consequences (PHC) determination of mining and reclamation. Collection and interpretation of information concerning ground water and surface water quality and quantity, as well as detailed geologic analysis, is required to adequately define the impacts of mining. This paper discusses the present day requirements and methodology of preparing a PHC for a large mining operation in the eastern coalfields.

Jan 1, 1997

By Milton E. Wadsworth, Ximeng Zhu

Impurity metals can markedly influence the anodic dissolution of gold in the presence of cyanide. Several important findings related to the influence of lead are reviewed and some new observations presented. Based on the effect of pH, the scan direction, and voltage, it may be shown there are three separate voltage regimes where lead influences the anodic dissolution of gold. These are related to Pb°/ HPbO2, Au-Pb /HPbO2, and HPbO2/PbC2; oxidation-reduction reactions which provide low resistance paths for electron exchange. The gold dissolution rate was determined by direct solution analysis and is compared to the rate implied by electrochemical measurements.

Jan 1, 2005

By D. R. Babich, E. R. Bauer

Noise induced hearing loss (NIHL) continues to be a problem in the mining industry. New noise standards (Part 62) promulgated by the Mine Safety and Health Administration (MSHA) are aimed at reducing NIHL in the mining industry. The National Institute for Occupational Safety and Health (NIOSH) is conducting a cross-sectional survey of noise sources and worker noise exposures to address NIHL in mining. Noise surveys, including full-shift worker noise exposure and equipment noise profiling, have been completed in several surface coal mines, with an emphasis on draglines. The results of these studies are reported, their implications concerning worker NIHL are addressed, and their application to administrative and engineering controls is discussed.

Jan 1, 2003

By W. Hu

Traditionally, coarse wolframite ore processing has been done almost exclusively by gravity concentration methods. However, there has been a depletion of rich and coarse ore reserves and a proportional increase in the mining of low-grade, fine-grained complex ore feeds. This change has resulted in the need for better slime-processing technology. Research and development activities in this area have gained momentum, and recent innovations appear promising. This paper covers the recent innovations that have been made in dealing with tungsten ore slime processing. The new techniques include the application of a centrifugal cone separator, high-intensity wet magnetic separator, the use of phosphonic and arsonic acids as collectors in ultrafine wolframite flotation, and combined processes.

Jan 1, 1989

By F. W. DeVries, J. Brent Hiskey

The search for noncyanide lixiviants for treating gold and silver ores and concentrates is not a new endeavor. However, in recent years, the overall activity to seek a less environmentally controversial reagent than cyanide has occasioned considerable developmental work. While the elegant economy and simplicity of cyanide, because of its selectivity and the ease of recovering gold and silver from the cyanide complexes, is well recognized, two failings have justified the search for alternates: increasing concerns and costs to assure avoidance of environmental damage from cyaniferous liquids and solids, and the need to simplify recovery of gold and silver from refractory ores. Generally, process development work to date on the alternate reagents has lacl<::ed environmental focus ( Hiskey and Devries, 1992). This paper covers briefly the chemistry of various alternates to cyanide and reviews their environmental implications. In each case, environmental overtones are reviewed following the chemistry. For ease of follow-up, the authors have listed sources of information in detail. Alternates examined include:

Jan 1, 1992

By Randy Fulton, Ignacy Puszkiewicz, George H. K. Schenck

Stuart Olson Construction, Inc. excavated 385m (1263 ft.) long twin tunnels with 6.25m (20.5 ft.) O.D., a portal and a cross-over for the Edmonton, "Metro". The work for Contract No. 76458, SLRT South Tunnel and Portal, in Edmonton, Alberta, Canada was performed in 1989 and 1990. NATM was specified because of the instability of glacial deposits. The contractor decided to use "two firsts" on this project: Fully mechanized NATM and a novel excavator¬mounted tunneling machine. An excavator was equipped with a cutter boom, and a loading and conveying system. This novel machine cost only about one-third of the price of a special NATM roadheader. This new combination of NATM and an excavator-mounted cutter boom offered a cost-effective alternative to shields, slurry TBMs and roadheaders for short tunnels in unstable ground. For NATM tunneling in hard rock or in mixed faces, the roadheader-type cutter boom can be replaced with an impact hammer (hydraulic breaker).

Jan 1, 1993

By M. Stoica

Bioremediation is a complex process which involves mass transfer, chemical and biochemical phenomena. In particular, the adsorption kinetics of a substance by biomass may by model by taking into account: - Enzymatic kinetics type; - Combined kinetics - enzymatic kinetics at the same time with the Monod type biomass growth; - Chemical kinetics for substance adsorption according to Freundlich and Langmuir ad-sorption isotherms; - New empirical kinetics models based on experimental data. In this paper modelling of kinetics of bivalent lead ions on live vegetal biomass (aquatic plant Pistia stratiotes) as well as of hydrocarbons on dead vegetal biomass (pyrolysed nuts) is studied (Stoica, 2004). Modelling was carried out using experimental data and relative equations with an error of 5%.

Jan 1, 2006

By Z. T. Bieniawski

In the past 15 years, rock mass classifications have experienced unprecedented development and have emerged as powerful practical methods for assessing ground conditions and tunnel support. Such methods as the RMR System (Geomechanics Classification) and the Q-System have provided many advantages over the classical Terzaghi rock-load method introduced in 1946. These new classifications have found wide applications all over the world but some doubts have been expressed and shortcomings pointed out. The author, who developed the RMR System, takes a penetrating look into the promises and the pitfalls of modern rock mass classifications. He dispels some misconceptions and shows how rock mass classifications can serve as effective and dependable design aids in tunneling.

Jan 1, 1987

By Gordon C. Gutrath

Queenstake Resources Ltd. has been exploring and mining alluvial gold deposits in the Yukon Territory and British Columbia since 1980. The five mines in production produced, in 1987, a total of 13,222 ounces. This paper will briefly review Queenstake&apos;s exploration program, property descriptions and mining methods, environmental concerns and a comparison of costs. (Sueenstake has been successful in developing a cash flow base from these operations that provide the capital for the acquisition and exploration of new, and hopefully, larger scale gold producers. NOTE: The historic alluvial mining unit of ounces per cubic yard and English units of measurement have been used throughout this paper. Dollars are Canadian unless otherwise noted.

Jan 1, 1988

By C. Patrick, D. Puckett

The feasibility of monitoring the locations and vital statistics of equipment and personnel in surface and underground mining operations has increased with advancements in radio frequency identification (RFID) technology. This paper addresses the use of RFID technology, which is relatively new to the mining industry, to track surface equipment in mine pits, loading points and processing facilities. Specific applications are discussed, including both simplified and complex truck tracking systems and an automatic pit ticket system. This paper concludes with a discussion of the future possibilities of using RFID technology in mining, including monitoring heart and respiration rates, body temperatures and exertion levels; monitoring repetitious movements for the study of work habits; and logging air quality via personnel sensors.

Jan 1, 1999