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By Pradip

Chelatang agents, because of their metal specificity, can function as effective mineral processing reagents. A brief review of the work carried out in this area is presented. Some of the salient features of mineral flotation and flocculation with chehting-type reagents, such as bulk us. surface chelation, the role of pH, mineral solubility, solution chemistry of reagents, and temperature, are illustrated with appropriate examples. The problems associated with the commercialization of chelating reagents for ore beneficiation and the research efforts required in this area are also discussed.

Jan 1, 1987

By Paul F. Richardson

Liquids containing suspended solids are encountered in most mineral processing applications. Solids levels cover a very wide range, from ppm levels in cooling water systems to slurries containing greater than 70% solids. When the aqueous phase is recycled or further processed, a solid/liquid separation process is used. Chemical additives used to carry out this process are called coagulants and flocculants. In other cases, one seeks to control or modify the properties of the suspension. Dispersants are chemicals used to aid in suspending solids in a liquid as well as to control the properties of the resulting suspension. Dispersants find a range of uses in mining and mineral processing such as scale control, filter aids, flotation aids, and slurry viscosity modification. Materials used as dispersants include inorganic salts, alkalies, organic surfactants, and polyelectrolytes. This paper discusses the use of dispersants in mineral processing, with an emphasis on control of slurry viscosity. The mechanism of dispersion and factors that affect the choice of dispersant will be discussed.

Jan 1, 1986

By John P. Dunford, Lewis A. Martin

Researchers from the Spokane Research Laboratory, National Institute for Occupational Safety and Health, in cooperation with engineers from the Department of Mining and Geological Engineering, Montana Tech, Butte, MT, conducted tests to evaluate the tensile strength, fiber count, and adhesion of shotcrete applied to panels at the Chief Joseph Mine, a research and training facility operated by Montana Tech. The tests were conducted in the mine ramp 45 m (150 ft) inward from the access portal at a 15.25-m- (50-ft) long test area divided into five 3-m- (10-ft) long sections. The shotcrete was applied with an Aliva 240.5 machine fitted with a predampener. Different amounts of fiber were entrained for each panel. Background data for the tests were obtained from earlier tests in Nevada, where the typical amount of fiber in the shotcrete is 6.54 kg/m3 (11 lb/yd3). All shotcrete was applied to a minimum thickness of 76 mm (3 in). Cylindrical cores were drilled at the wall-rock interface, and adhesion was tested after 28 days of curing. The goal of this research is to reduce the need to install multiple supports at the advancing face by creating a safer mining system that limits the time miners are exposed to unprotected roof.

Jan 1, 2005

By B. Denby

Recent advances in virtual reality (VR) have resulted in major opportunities for improving the safety training of mine workers, supervisors and managers. VR has the potential to expose mine personnel to hazardous situations in a safe, highly visual and interactive manner. Customized simulations of mine layouts, dynamic operations and mine environment can be set up, and mine personnel can be allowed to move around the virtual mine, making decisions at key points. The consequences of both correct and incorrect decisions can be immediately fed back to the trainee.

Jan 1, 2000

By Chien D. Ngo, Andre Bachmann, Rainer Bunge

The remediation of contaminated sites has gained great importance in many industrialized countries. One method for cleaning the polluted soils from such sites is "soil washing," the scope of which is the separation of the contaminants from the soil. Soil washing is an outstanding example for a successful transfer of technology from Mineral Processing to Environmental Engineering. This presentation intends to introduce the Mineral Processing Engineer to soil washing through a short review of the fundamentals, and the discussion of an example for a successful soil cleaning operation in Switzerland.

Jan 1, 1995

By George Bárdossy

Most of the bauxite deposits in Europe belong to the karst type. They are located mainly ill Southern Europe along the Mediterranean Sea and in the Ural Mountains. Lateritic bauxite deposits occur on the Russian Platform, in Poland, Northern Ireland and in Turkey. Tikhvin-type deposits arc found on the Russian Platform. Bauxite formation in Europe started in the Middle Devonian. The main bauxite forming period was the Upper Cretaceous. Very few bauxites are younger than Eocene. Most deposits are covered by overburden of up to 1000 m. Prospecting is carried out by drilling. Several geophysical methods are used to detect the hidden deposits. Geostatistical methods were introduced in several countries for evaluation of the reserves and the geometry of the deposits. Data on bauxite production are given for 1982 and since the beginning of mining in Europe.

Jan 1, 1984

By K. N. Han, P. B. Queneau, A. Stojsic, M. J. Collins, V. J. Ketcham, R. M. G. S. Berezowsky, W. D. Vardill

The bulk of the ore found in the Lihir Island deposit is refractory in nature, with the gold contained in auriferous pyrite. In support of an evaluation of the development of this deposit by Kennecott (a wholly owned subsidiary of RTZ) and Niugini Mining Ltd., testwork has been carried out at the Sherritt Research Centre to demonstrate the amenability of the Lihir ore to pressure oxidation pretreatment to liberate the refractory gold. The results of pilot plant treatment of the Lihir ore in a continuous circuit with a feed rate of between 10 and 30 kg/h ore are described. The integrated circuit comprised pressure oxidation, residue washing, and gold recovery from the washed residue by carbon in leach or carbon in pulp cyanide leaching. Significant factors affecting gold recovery included temperature and retention time in the pressure oxidation step, and the concentration of soluble chloride in the feed. Gold extraction from well washed ore, after oxidation at 210°C for 66 minutes in the autoclave, was typically between 94 and 96%, compared with less than 30% by direct cyanidation.

Jan 1, 1993

By E. Topuz, M. J. McPherson, I. M. Konduri

The research is carried out to investigate the flow mechanics and effectiveness of face ventilation using induction fans, as an effort to provide a more efficient alternative to conventional auxiliary duct or brattice ventilation systems. The induction effects and plume longevity of fluid jets are being studied with the help of a plexi-glass model, using water as the fluid medium and creating a system that is dynamically similar to the flow in mine headings. This scaled model represents a typical 1.5m x 6m x 25m heading connecting to a crosscut. Reynolds Number criteria are used to obtain dynamic similarity of the flow in the designed model to simulate real mining conditions. The role of various parameters such as nozzle position in three dimensions, airway roughness, nozzle geometry, and flow rate in the jet are studied. During the laboratory tests, flow visualization techniques, coupled with still and video photography, were employed to identify the flow patterns. The results indicate that in typical coal mine headings, jet fans can produce effective face ventilation for distance up to 30 meters.

Jan 1, 1995

By Steven J. Schafrik, Michael Karmis, Zacharias Agioutantis

3-D or pseudo 3-D visualization of orebodies and mining related processes such as loading and tramming, are now commonly used by the mining industry. An approach is presented that can aid the engineer in creating the visualizations necessary for accurate presentations for use in public relations, safety training, production projections, reclamation plans, etc. It is shown that the creation of such digital representations of mining environments are independent of the mining package used to create the original mine design. Once a proper model has been created, any view of the areas is possible. These views can be taken from any number of stationary points or entered into an animation showing the progress of a mining construction. The paper focuses on the presentation of the steps used to accomplish the visualization and an example is for a quarry fill placement project.

Jan 1, 2002

By James G. Donovan, Mario G. Karfakis

A large percentage of Southern Appalachian coal reserves are located in seams less than 36" thick. As thicker and currently more mineable deposits are exhausted, methods of underground thin-seam extraction must be developed. Past experience with highwall mining of thin-seam coal has indicated that recovery rates tend to be lower than in conventional operations. It is suspected that this will also apply to underground thin-seam mining, regardless of proposed technology or mining method. Backfilling is one alternative for thin-seam coal mining; although backfill has been used extensively in hard rock mining its use in coal mining has been limited. The ability of backfill to provide additional ground support may enhance coal recovery by allowing for the design of undersized pillars. Backfill is capable of providing additional ground support by restricting lateral deformation of surrounding coal pillars and roof. This additional support can result in significant increases in recovery from thin-seam coal deposits. However, the overall feasibility of backfill is dependent on the in situ behavior of the fill material, the properties of the fill, the effects of the filling method on the total mining operation, and the cost of filling per extra ton of coal recovered.

Jan 1, 2001

By J. C. Yingling, R. J. Sweigard, P. W. Conrad, J. M. Ringe, D. H. Graves

Much of the land reclaimed since enactment of the 1977 Surface Mining Control and Reclamation Act is overcompacted. Research has shown that excessive compaction in replaced growing media is detrimental to the establishment of trees. If trees are to be grown on reclaimed surface mined sites, something must be done to alleviate this excessive compaction. Dry bulk density and penetration resistance are two soil parameters that can be used to indicate the level of compaction in reclaimed growing media. The University of Kentucky developed test cells on reclaimed areas at a surface mine in eastern Kentucky to determine the impact of tillage (ripping) on soil compaction and tree survival rate. The ripping methods being evaluated include shallow tillage using conventional farm equipment and deep tillage using a dozer with a ripping arm. Each test cell was planted with various species of trees, and for the first two years of tree growth, data were collected at these test cells for soil dry bulk density, penetration depth and resistance, and survival rate of trees. These data were statistically correlated to determine how ripping affects the relationship between soil compaction and tree survival rate.

Jan 1, 2003

Iron ores may be upgraded by flotation of iron oxides or siliceous gangue using either cationic or anionic collectors. The electrostatic mechanism of adsorption can account for the complex chemistry involved. In industrial practice, only cationic silica flotation is used at present in North America. Some of the seemingly paradoxical phenomena of cationic silica flotation behaviors in meeting the demand for low silica concentrates are reviewed.

Jan 1, 1989

By R. A. Metz, Michael M. Easdon, Michael J. Fiannaca

Disseminated epithermal gold metallization occurs within a breccia unit interpreted to be a submarine debris flow. Gold is associated with oxidized pyrite, fluorite, and jasperoidal silica. A minimum of 8 Mt (9 million at) of open-pittable mining reserves will be cyanide heap leached as run-of-mine ore at a rate of 0.9 Mt (1.0 million stpy). Careful evaluation of the combined results of successive sampling projects has established the pit plan, minable reserves, and process metallurgy of the operation. The sampling procedure utilized for a given test depended upon geological interpretation as well as the procedures, successes, and failures of previous tests. This paper summarizes the sampling and testing procedures of the development effort in light of the project goals and attendant problems in achieving them.

Jan 1, 1992

By V. Srajer

Several optimization approaches used by the Canadian mining industry were used to investigate surface coal mining operations in Canada. A computer program was applied to optimize truck/shovel systems and for various analyses. The analyses of eight western Canadian coal mines included investigation of fleet imbalance, under- and over trucking, development of the criteria for automated truck control, comparison study of various haulers and loaders, haulage layout, driving conditions, machine performance, servicing and maintenance policies, etc. Each property investigated supplied background information for the study and cooperated in optimization studies. The truck/shovel system optimization study is demonstrated as a test case to outline procedures and step-by-step instruction for similar applications.

Jan 1, 1989

By J. A. Herbst

Mineral liberation modeling can be traced back to the early work 0fA.M. Gaudin up through more recent population balance modeling by R.p. King, J.A. Herbst and G.T. Adel. A more micro-scopic look was taken at the University of Utah in the form of the J.E. Sepulveda and J.D. Miller Pargen model which permits the creation of an arbitrary shape, multiphase particle made up of discrete grains. Recent work on image analysis and tomographic analysis by J.D. Miller and C.L. Lin have laid the experimental ground work for model validation, but until now it hasn't been possible to include the necessary physics of the particle stressing process to allow the development of a 'ffirstprinciples"mode1 which does not presuppose a "mode” of liberation (e.g., random or by detachment). Recent developments in discrete grain breakage (DGB) modeling now make a generalized physics based model feasible. This paper describes current work that is being done to develop a physics based discrete grain liberation (DGL) model. Two-dimensional and three dimensional simulation results exploring the effects of particle size, phase properties and loading type are presented. Relationships between energy based liberation efficiency, degree of random liberation and material properties are identified.

Jan 1, 2005

By Pasi Latva-Pukkila

Underground rock drilling has gone through intense development during the last 25 years. Mechanization and hydraulics have greatly increased the efficiency of drilling and improved the environment of the drill operator. As the total economy has become more and more important, the development has resulted in greater overall economy in drilling. The latest evolution step is computerization of drilling equipment. Computerization has been applied to tunnelling jumbos, long- hole drilling rigs and bolting rigs. With today's technology computerization is the natural way to increase capacity and productivity of the drilling process. However, it is still impractical to implement total "robotic" drilling. In computerized drilling the operator's role continues to be vital in controlling the drilling process and in analyzing the effect of individual parameters on the whole excavation process. Today this is called "CAD" - Computer Aided Drilling.

Jan 1, 1989

By D. R. Lowe

Silicic volcanic ash and its alteration product, bentonite (montmorillonite and cristobalite), occur widely within sedimentary phosphate deposits. The genetic link, if any, between volcanism and phosphate deposition has yet to be satisfactorily established The phosphatic member of the Santa Margarita Formation (upper Miocene) in northwestern Ventura County, California, consists of approximately 15 per cent volcanic ash and bentonite. Ash and bentonite units greater than one foot thick can be subdivided into a lower zone of airfall origin and an upper zone of mixed ash and terrigenous detritus washed in from surrounding land areas. This upper zone also contains up to 20 percent phosphate pellets. These thick volcaniclastic units are typically overlain sharply by thin beds (less than 6 inches thick) of relatively pure, silica-cemented pelletal phosphorite. The shelf basin in which the phosphatic sediments accumulated was characterized by quiet, reducing but not euxenic bottom waters; Abundant decaying organic debris, mainly diatoms, served as a reservoir of readily available phosphate. The sudden influx of a large volume of silicic volcanic ash into this basin and its subsequent alteration to montmorillonite had two profound effects on thechemistry of the interstitial and bottom waters: (1) during alteration magnesium was removed from these waters and incorporated into the montmorillonite lattice, and (2) the pH of these waters increased as alteration progressed Both of these effects led to the crystallization in the bottom waters of carbonate fluorapatite. This accumulated as thin phosphorite beds immediately above the volcaniclastic units.

Jan 1, 1972

By C. J. Bise, D. A. Poukhovski

Hazard recognition and prevention of accidents are two components of the 30 CFR 48 training requirements, which are mandated for new miners and newly employed experienced miners. These components are also part of the annual refresher training course required of all miners. In these categories, instruction shall include the recognition and avoidance of hazards present in the mine and shall include a review of accidents and their causes. Unlike instruction preparation for fact-based material, program development for hazard recognition presents a particular challenge to safety-training specialists, because they are often limited in their ability to adequately gauge the level of awareness of the individual prior to training. Further, they must also assure that the training is relevant and presented in a thought-provoking manner. Computer-based instruction is particularly well suited for assisting trainers in developing hazard-recognition topics, because it can be used in pretraining and posttraining modes for assessment of training effectiveness, in addition to its use as a presentation tool. This article presents a recent approach, developed at The Pennsylvania State University, that applies the technology for the assessment and instruction of accident prevention through hazard recognition. The application is prepared for surface coal mines.

Jan 1, 1999

By W. Blake, J. Mahaut, W. Hustrulid

Division II at Kamoto mine in Kolwezi, Zaire represents a transition zone between Divisions I and III where transverse and longitudinal cut-and-fill rooms were being mined. Because this transition zone had been geologically depicted as being badly faulted the mining in this division had been deferred to a future time. However, to increase production and to reduce mining costs by carrying out the mining of the 3 divisions simultaneously, it was decided to mine Division II. The mining research group of Gecamines was given the task of designing a mining geometry then testing this design in a full scale test. Based on an evaluation of the faulting and fracturing of the 2 parallel orebodies and on an extensive in situ testing program preliminary mathematical analyses were used to develop and evaluate room and pillar designs in the 35°-65° dipping bedded formations. Based on these analyses and the constraints of having to fit the design of Division II to grade into Divisions I and III in a logical manner, a mining geometry for Division II evolved. To test this design an instrumented room was excavated in the most critical area. The results of this full scale testing showed that the behavior of the roof and wall rocks were as had been predicted by finite element computer model studies which incorporated the material properties and results of the field testing. The room geometry design was both judged and observed to be stable, hence mining commenced.

Jan 1, 1977

By Richard B. Berg

Until its closure in 1999, the Antler was North America's only active chlorite mine. The mine is located 25 miles (40 km) southeast of Butte in the Silver Star district - an old Montana gold mining district. In 1975, two prospectors searching for talc re-examined a prospect showing a green, fine-grained mineral resembling talc. Following identification and testing of this magnesian chlorite (variety clinochlore), Cyprus Industrial Minerals began processing ore from this deposit in 1976. Chlorite veins ranging up to 30 feet (9 m) in thickness were formed by essentially complete replacement of Precambrian (Archean?) quartzofeldspathic gneiss. Chlorite replacement was controlled by near- vertical faults. These chlorite veins, typically surrounded by envelopes of sericitic alteration, were formed by the introduction of magnesium-rich hydrothermal fluids, probably related to the Proterozoic talc-forming event in southwestern Montana. Luzenac America, Inc. acquired Cyprus' talc operations in 1992, and continued to mine this deposit until the ore body was mined out in March 1999, and the mine was reclaimed. Total sorted ore production from this deposit is about 250,000 short tons (st) (227,000 metric tons [mt]). Chlorite from this deposit was primarily used in ceramic and paint applications.

Jan 1, 2001