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By Scott G. Britton

In the real world of coal mining, the bottom line for almost every support project decision is economic (i.e., what is it going to cost?). Up to this point, I have discussed the methods to improve the performance of typical support projects by better installation, materials, and techniques, thus lowering the impact of the bottom line cost. In this chapter, 1 shall explore what costs are relevant in mining construction, and how these costs are developed. The chapter centers around two major discussions: (I) developing cost accounting techniques, and (2) cost-estimating procedures for support construction. Each focuses on the fundamentals of practical cost considerations necessary for decisions on construction projects underground. Since cost accounting, economics, and investment planning are all subjects which warrant complete discussions on their own, this chapter will focus on distilling the important concepts required by a planning engineer into an easily understandable presentation.

Jan 1, 1983

By Daryl L. Gusey, John T. Neubert, Matthew A. Sares

The Colorado Geological Survey completed an inventory of environmental degradation associated with abandoned and inactive mines on National Forest System lands in Colorado. In the course of the inventory, areas with naturally occurring acid rock drainage were also noted. Approximately 18,000 abandoned mine- related features were inventoried, including about 900 features that are considered significant enough environmental problems to warrant further investigation. Water quality data, such as pH and conductivity were gathered at all features where water was present, such as draining adits, seepage at the toe of dumps and tailings, and standing water in shafts. Samples were taken where field tests indicated low pH andlor high conductivity, including several areas with naturally occurring acid rock drainage. Samples were analyzed for dissolved and total metals, and for selected anions. All mine locations and data collected by the field geologists were entered on field forms and, subsequently, into a computer database and GIS format. With the information provided by the inventory, the Forest Service, in cooperation with other agencies, has been able to prioritize abandoned mines for reclamation. In most cases, cleanup is approached on a watershed basis. Mines in priority watersheds have been selected for reclamation first. Watersheds where studies prerequisite to cleanup are occurring include the upper Anirnas River, Willow Creek (tributary to the upper Rio Grande), Chalk Creek (tributary to the upper Arkansas River), the Uncompahgre River, and the Alamosa River. During the inventory, evidence of naturally occurring water quality degradation was found in areas where little or no evidence of mining activity exists. These areas include the upper Alamosa River, the Middle Fork of Mineral Creek, Peekaboo Gulch, and Handcart Gulch. Water from these natural sources has been found to significantly exceed Colorado water quality standards for several metals.

Jan 1, 2000

By E. A. Metz

It has been approximately four years since the International Agency for Research on Cancer (IARC) reclassified crystalline silica as a "group one" substance. Since then, crystalline silica has been considered a human carcinogen. Silicosis is a preventable disease, and several aggressive campaigns have been developed to increase awareness of silica-dust-related problems in the industrial environment. New analytical techniques are now being developed to determine quantitatively the amount of crystalline silica in materials. Yet, still much is to be learned about the surface properties of silica and the way in which the disease progresses into full-blown silicosis. This paper discusses the interaction of free radicals generated by the mineral particles and lung tissue. It is the cell injury and DNA damage that progresses to fibrogenesis. Freshly fractured surfaces of silica contain free radicals. These free radicals play an important role in the stimulation of the alveolar macrophage and the development of the inflammatory reactions leading to the fibrotic response caused by silica. Engineers, scientists and physicians need to discuss the mineralogy of silica and the technical issues concerning the development of silicosis.

Jan 1, 2000

By David Field, David Powell, Richard Hulsen

The Mission Valley Light Rail will loop through San Diego State University (SDSU)and to minimize the impact of construction most of the works will be underground. The project will require construction of a 330-m long (1080-ft), 11.24-m wide (36.9-ft),single twin track tunnel through Stadium Conglomerate, a poorly cemented dense sandy gravel with cobbles. Key technical issues are discussed including the ground conditions and predicted ground response, the use of sequential excavation methods to control deformations and specific construction concerns such as instrumentation and monitoring. Management of the construction process to minimize risk is particularly important in this environment and the strategy selected to control the works is also considered.

Jan 1, 2001

By James P. Dorian, James M. Otto

The value of exported nonenergy minerals from the less-developed countries has increased substantially between 1970 and 1985, but their market share relative to world exports has remained stagnant. Of the top twenty minerals exporters, only four are developing countries. Production capacity in the developing countries is shown to be less sensitive to demand downturns than capacity in the developed countries. Two approaches to the management of cyclical minerals demand are given using examples from India and Papua New Guinea. The authors conclude that pro¬tective policies implemented by developing nations have, barring a few exceptions, relatively little impact on the chronic nonfuel minerals oversupply problem.

Jan 1, 1989

By T. M. Karppanen

Shotcrete is used both in mining and tunnelling for supporting rock. Both dry and wet processes are used for shotcreting, and each produces good quality concrete. Thick shotcrete layers function as a concrete arch supporting loose rock. Thin layers prevent relative movements between the blocks of rock due to the fine concrete in the cracks and joints. No progressive fallouts occur since key blocks are kept in place. Rockbolts are often used together with shotcrete in order to create an arch around the tunnel making the rock to support itself. Shotcrete is sprayed either manually or by means of mechanized equipment. The aim is to spray required the layer thickness in one pass and with a minimum amount of rebound. Sprayed layers should also be as even as possible. The tip of the nozzle should be moved in circular movements. The shotcrete should be sprayed at a right angle to the rock surface; the optimum distance from the nozzle to the application surface must be found by experiment. In a mine shotcreting forms a materials handling system which includes batching, transporting and the actual shotcreting. The equipment used vary depending on the spraying method, mining conditions and the location of the mine. Shotcreting is performed with a purpose-designed unit in most cases where operation is mechanized. The shotcreting unit consists of a spraying machine with a hose and a nozzle, an additive system, a manipulator and a mobile carrier with all the necessary controls and accessories. The key element of the unit is the shotcreting manipulator which holds and guides the nozzle as required. The manipulators currently in use are hydraulically operated, and their remote controlled booms are also often called robots. These manipulators have enabled users to increase their output capacities, to remove the operator away from unsafe areas and from the influence of dust and rebound. Furthermore, they improve the shotcrete quality and reduce shotcreting costs.

Jan 1, 1989

In the mining industry and in new and expanding fields, such as electronics, nucleonics, and astronautics, a new type of manager has evolved. The name most generally used is project manager. His business is to create a product and the principal means through which he accomplishes this is project management. In this chapter, new information is the product of the project manager; as such the products, for which the computer methods described throughout this volume are designed, fall in the domain of project management. It has been the author's experience that project management is the management tool to effectively direct the information technology function within an organization. The purpose of this chapter is to describe project management and to identify and present a solution to the problems associated with project management in the development and application of computer methods in a minerals environment. Specifically, the problems to be addressed will center around: (1) recognition of the need for project management in terms of business-environmental factors and product characteristics, (2) formulation of a method of operation in terms of organization and implementation, and (3) application of project management to the minerals industry.

Jan 1, 1979

By George D. Roberts

Dams are constructed to retard the flow of water or debris; therefore natural forces are constantly at work to remove such obstructions. To circumvent nature and avoid expensive trouble with a dam requires thoughtful far-sighted planning, careful construction control and vigilant periodic inspections to detect and repair deterioration at its inception. Although the factuality of the foregoing statements is apparent, all too many have failed to consider them in the past as will many in the future. "The economic, but safe construction of dams calls for the highest order of technical knowledge, practical experience and sound judgment." (1)

Jan 1, 1967

By G. J. J. Aleva, A. H. Hilversum

The northern spur of the Bakhuis Mountains contains bauxite deposits on a dissected planation level, a region formerly indicated as the Adampada-Kabalebo area. Iron-rich laterites are ubiquitous on all more or less flat and horizontal to moderately sloping interfluves and planation levels. The known aluminous laterites and bauxites are restricted to those laterites that have relatively leucocratic and silica-poor parent rocks. The whole area is underlain by high-metamorphic Precambrian. In the northern half of the Guiana Shield at least four Cainozoic planation levels can be distinguished. The bauxite and aluminous laterite deposits are related to the oldest, Early Tertiary level. These deposits, occupying the highest positions in the present day landscape, show the destructive influence of post-laterite weathering, erosion and denud- ation; they are erosion remnants and as such are of irregular thickness, grade and shape. Consequently, exact mineable tonnages can only be determined after intensive and detailed sampling and evaluation, taking into account the latest technical and economic parameters. The bauxite potential of the region is negatively influ- enced by the complicated uplift history of the Bakhuis horst, and positively by the presence of suitable parent rock and possibly more than one phase of bauxitization.

Jan 1, 1984

By O. Ozcan, J. D. Miller, Z. S. Nickolov

The production of soda ash from trona (sodium sesquicarbonate, Na2CO3•NaHCO3•2H2O) resources has completely displaced the production of synthetic soda ash in the USA. Further, the utilization of other trona resources is under consideration in China, Turkey, etc. Recent research has been concerned with the development of flotation technology for the trona industry. In this regard studies on the flotation behavior of sodium carbonate salts: trona, sodium carbonate monohydrate and decahydrate, as well as the flotation behavior of sodium bicarbonate, are reported for both cationic (dodecyl ammonium hydrochloride) and anionic (sodium dodecyl sulfate) collectors. It has been found that strong flotation of sodium bicarbonate (NaHCO3) can be achieved with 100% recovery, while the other sodium carbonate salts do not float well. These results have been explained by FTIR analysis of aqueous solutions of Na2CO3and NaHCO3in a range of concentrations from very dilute to saturated conditions. The changes in the shape of the O-H stretching band of water are correlated with the flotation behavior of Na2CO3salts and NaHCO3. In addition, the absorption band of the carbonate ion at ca. 1385 cm-1is used to monitor its interactions with water and/or other ions in solution. The infrared results demonstrate thatNa2CO3acts as a water structure maker, leading to an extensively hydrated surface that accounts for the poor flotation of most sodium carbonate salts. In contrast, NaHCO3does not have this characteristic and consequently complete flotation is possible with both cationic and anionic collectors. These results support the previous water structure analysis for soluble salt flotation of alkali halides and other oxyanion salts.

Jan 1, 2003

By Cynthia M. Walck, S. K. Grant, R. D. Hagni

The Post Gold deposit is located in the northern part of the Carlin trend. The mineralization at Post occurs in proximity to a Jurassic-Cretaceous composite stock. Most of the gold at Post is hosted by non-metamorphosed calcareous siltstone and highly altered diorite, adjacent to the low grade skarn. Endoskarn, exoskarn, hornfels and marble are developed outward from the intrusive. The skarn is composed dominantly of diopside, tightly intergrown with gannet, k -feldspar, and sphene. The highest grade gold values are adjacent to the skarn, which acted as a permeability barrier to fluid migration. Post is the first Carlin-type deposit at which a skarn has been recognized to play a significant role in the localization of gold.

Jan 1, 1990

By R. Woods, O. A. Kiehn, C. A. Born, F. N. Bender

Development of the flotation reagent scheme at Climax Molybdenum Company's mine at Climax Colorado is reviewed. Features of the mineralogy, milling practice and background of reagent changes are outlined. Special attention is given to the hitherto unpublished details of the application of depressants for copper and lead impurities. The present rougher flotation reagent scheme utilizes a neutral hydrocarbon oil, low in unsaturates and wax, as collector with a sulfated coconut oil emulsifier and pine oil frother. Lime and sodium silicate are used as rougher conditioning and slime dispersant agents. Chalcopyrite and galena impurities are de- pressed in both rougher and cleaner plants by stage addition of Nokes reagent and sodium cyanide to yield a metallurgical grade molybdenite concentrate containing greater than 90% molybdenite and less than 0.5%, 0.1% and 0.05% iron, copper and lead impurities, respectively.

Jan 1, 1976

By David V. Fitterman, David L. Campbell

We've used direct current resistivity (DC), electromagnetic (EM), induced polarization (IP), and ground-penetrating radar (GPR) geoelectrical methods to study mine dumps. The results reflect lithology, pore water saturation, and dissolved solids in the pore water. If the pore water has a pH less than 5, conductivity maps can indicate acid generating potential. IP measurements can help distinguish mineralogy in mine dumps, especially concentrations of sulfide minerals. EM and DC can help locate acidic/high TDS groundwater associated with mine dumps. GPR methods failed at the sites we studied in the West. Our own conclusions are augmented by those from the recent literature.

Jan 1, 2000

By Glenn A. Gruber

The conditioning of phosphate flotation feed with anionic flotation reagents was identified as a high- priority research topic during a beneficiation work- shop sponsored by the Florida Institute of Phosphate Research (FIPR). FIPR subsequently solicited research proposals to identify the mechanisms of reagent adsorption, to determine scale-up relationships for conditioner design, and to investigate the effect of conditioning variables on reagent adsorption and flotation performance. The two-year research project was awarded to Jacobs Engineering. Somasundaran, Inc., the University of Florida Mineral Resources Research Center, and the U.S. Bureau of Mines assisted Jacobs. Two mechanisms of anionic collector adsorption were detected by spectrographic analyses and confirmed by microcalorimetric measurements. The mechanisms provided a sound technical basis for the empirical practice of conditioning phosphate flotation feed at a high percent solids. Tests performed in laboratory and pilot-scale agitated tanks indicated that power intensity may be used as a reliable scale-up parameter for anionic conditioning of phosphate slurry. Excessive agitator speed during conditioning was found to be detrimental to anionic flotation performance. Some dimensional ratios of anionic conditioners were found to be consistent with good utilization of agitation energy. Laboratory conditioning and flotation tests demonstrated that adsorption of collector onto phosphate and the subsequent recovery of phosphate in anionic flotation were significantly influenced by the quantity and quality of water used in conditioning. Conversely, the quality of water used in flotation was more influential on the recovery of quartz in the concentrate. A comprehensive survey of anionic conditioners and conditioning practice in the Florida phosphate industry was also performed during this project. The study clearly showed that flotation testing with laboratory conditions typical of scientific research gives different results than laboratory testing with simulated plant conditions. The effects of test conditions on laboratory test results should be carefully considered by investigators planning and conducting applied research.

Jan 1, 1999

By G. Baudet, M. Save

Ethoxylated phosphoric ester surfactants were evaluated as collectors for flotation of carbonates from sedimentary phosphate ores, at slightly acidic pulp pH, using sulfuric acid or sodium fluorosilicate as a phosphate depressant. With 12 to 15 carbon atoms in the hydrophobic chain, maximum collecting power was observed for 9 to 10 ethylene oxide units. Only fine carbonates, ranging in size from about 20 to 160 µm or 40 to 200 µm, were effectively removed with phosphoric ester collectors. Utilization of seawater, or water of extremely high hardness, did not detrimentally affect selectivity. Silica, silicates, and residual fine carbonates can be separated in a second flotation stage, with primary amine as a collector. Coarse carbonates are separated by direct flotation of phosphate with fluoride ion as a phosphate activator and primary amine as a collector. In a seawater pulp, fluoride ion was not required. Typical examples of laboratory and pilot- scale test results are given to illustrate capabilities of the various flotation flowsheets.

Jan 1, 1999

By I. K. Kapageridis

Environmental management and planning requires the integration of large volumes of disparate information from many sources and the analysis of this information with efficient tools for assessment and evaluation. Effective methods of communication that allow interactive participation in the planning, assessment and decision-making processes are also very important. The VULCAN software package from Maptek (Pty) Ltd comprises a large number of 3D graphical tools within an interactive 3D interface called ENVISAGE. These tools are designed and developed to help engineers and scientists to identify and solve environmental problems. The combination of VULCAN 3D Software and the I-SiTE 3D Laser Imaging system leads to powerful solutions for environmental management. This paper presents the capabilities of this integrated system and its applications for environmental management.

Jan 1, 2002

By A. M. Alfantazi, R. R. Moskalyk

Over the years, improvements have been made in the recovery of nonferrous metals, including improvements in the areas of mineral processing, pyrometallurgy and hydrometallurgy to extract cobalt as a byproduct from host minerals containing mainly nickel, copper and associated precious metals. At present, the technological emphasis is on solvent extraction coupled with electrowinning (SX-EW) for lateritic sources of supply within the Southern Hemisphere, such as in Australia and New Caledonia. Although sulfide-bearing ores, such as those found in Canada and Russia, will serve as a viable long-term source for cobalt, a ubiquitous metal, the future trend is anticipated to be in the implementation of compact and efficient SX-EW facilities that apply state-of-the -art innovation with environmental compliance This paper serves to collate the known practices for the recovery of market-grade cobalt by means of electrowinning from either an aqueous sulfate medium or chloride medium after upstream leaching, solvent-extraction and solution-purification procedures. For completeness, other commercial production techniques for the recovery of cobalt as a sulfide or oxide product are included in the summary of current cobalt processing practices.

Jan 1, 2000

By David Morrison

On the Corramandel Peninsula of New Zealand, the Waihi Gold Mine has undergone a major redevelopment. The upgrade included the construction of two very large overland belt conveyors, both rated for a capacity of 6000tph. The first of these conveyors (CVR2) traverses a total of 1600m over undulating terrain, including a significant section running through tunnels. A large hill is climbed, just after the mid-section of the conveyor run, before dropping back down prior the discharge point. The second of these conveyors (CVR8) traverses 1100m along an alignment with a horizontal curve, a number of vertical curves and a significant lift before the discharge point. The CVR8 conveyor also included a shuttling head pulley arrangement. The mine they service is inside the town of Waihi. The conveyor alignment runs through the town and out to the metallurgical process site on the outskirts of the municipal area. This paper documents the engineering process that took place in the design of these conveyors. The Martha Hill mine in Waihi, New Zealand is unique. The mine is placed in the township. Consequently there are quite stringent environmental limitations on the mine's operation. In [Figure 1] the proximity of the mine to the town is shown. In the top-centre of the photograph the alignment of the existing smaller overland conveyor can be seen leading from the mine to a tunnel through the hill in the background.

Jan 1, 2000

By O. Guyot, A. Broussaud, J. Björkman, P. Söderman, P. O. Samskog

Model-Based Expert Control systems (MBEC) are on-line supervisory dynamic optimization systems which combine the ability of a phenomenological model to generate a large amount of information about the state of the process and predict its evolution, with the flexibility of a rules-based approach to take plant constraints into account and apply a complex control strategy. For its new concentrator started in 1995 in Kiruna (Sweden), LKAB has implemented a progressive grinding flowsheet with closed-circuit autogenous grinding followed by closed-circuit pebble grinding with ore pebbles. The standard for instrumentation in this new plant is very high. The control hardware consists of a Distributed Control System (DCS) through which the operators interact with the plant, supplemented by a site-level Management Information System (MIS). A state-of-the-art MBEC system was imbedded in the MIS by the authors before plant start-up. It consists of several modeling and expertise software modules: a phenomenological process model and a Kalman filter estimate continuously the state of the process, an optimizer calculates an optimum feedrate, while rules-based modules establish production targets and key process set-points. The decision to install the MBEC system as an integral part of the new plant before start-up illustrates the current maturity of the technology, i.e., enough know-how was accumulated through former projects to design and develop the system to a large extent without accessing the plant. The feasibility and the power of dynamic optimization systems were previously demonstrated in Kiruna pre-existing concentrator by the authors. First, a MBEC system was installed on the three existing pebble mill circuits, providing both an increase in quality (stabilised size distribution) and a 10% increase in capacity. An on-line expert control system with limited modeling capabilities was also installed in the existing flotation plant, with the aim of stabilizing phosphorous content in the concentrate and optimizing collector additions. Both objectives have been achieved.

Jan 1, 1995

By F. C. Turin, T. L. Friend, A. G. Mayton, J. S. Jaspal, W. J. Wiehagen

This paper describes the serious injuries that have occurred to bulldozer operators working at domestic coal, metal and nonmetal mines in the United States. A serious injury is defined as one that results in either a fatality or in lost work time. Examined were 873 injury records compiled by the Mine Safety and Health Administration (MSHA). The time period covered was 1988 through 1997. These injuries resulted in 18 fatalities and 31,866 lost work days. All of these injuries occurred to dozer operators while they were performing common production tasks. An injury classification system was developed to code the narrative information that describes the circumstances surrounding the injuries. Jolts and jars accounted, for 604 or 70% of the serious injuries to bulldozer operators, and jolts and jars accounted for 75% of the workdays lost. Vertical jars comprised the largest set (354 incidents) of jolting and jarring injuries. In more than half of these incidents, the operator was backing up the dozer. Working near an edge carries significant risk for fatal injuries. Of 116 incidents where the dozer fell over an edge, rolled over or fell into a hidden void, 14 (12%) resulted in fatal injuries. In cases where the dozer operator either jumped or was thrown out of the cab in a fallover or rollover, seven out of 17 of the operators were killed. This study finds that further reductions in injury risk would require more widespread use of seat belts; consideration (and maintenance) of the seat and seat suspension systems that might reduce injury risk from jolts and jars; research interventions to assess the effect of alternative engineering designs to dampen or isolate the effects of shock and vibration; and continued attention to skilled performance, i.e., the integration of hazard awareness, recognition and response with dozer operational skills.

Jan 1, 2003