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By T. F. Torries

Market data commonly perceived as being useful to industry for decision making include prices, production and trade quantities, production and transportation costs, stocks, customer's needs, and competitor's qualifications. Costs and factors affecting costs are particularly important in determining competitive positions and possible future prices. These costs include relative cost of production as well as cost experienced by the buyer in making the final product. Care must be taken to calculate costs in a consistent manner to achieve meaningful analyses.

Jan 1, 1987

By R. Sawyer, M. Sadler, M. Holdworth

Greens Creek is a high grade Ag/Au/Pb/Zn deposit located in southeast Alaska. Maximizing the Net Smelter Return revenue from the fine grained mineralization is a dynamic process given changes in metal prices, smelting terms, ore grades and flotation characteristics. This paper discusses the evolving concentrate production strategy, and how it is affected by such factors as ore and concentrate specifications and by market conditions. Also described is the development of an on-line computer program that provides the mill operators with real time NSR data and a means for optimizing Net Smelter Return.

Jan 1, 2002

By K. Nagata, T. Kawashima, S. Tejima

The expanding volume of maritime coal transportation is intensifying the problems concerning large vessel service, port construction, trans-shipment, and environmental control. The major problem is the shipment of coal. Customary methods for bulk transfer must be improved and new systems developed. Slurry unloading has a key role in the new systems. This report reviews progress in slurry transportation research that has been done in Japan since the 1960s, when large-scale experiments for domestic transportation were done. Experiments on the effects of vibration on the slurry cargo and on reslurrying are focused on.

Jan 1, 1987

By G. Blackwell, E. Bozorgebrahimi

The trend in open pit mining has been to maintain cost competitiveness through economies of scale, particularly by implementing larger trucks and shovels. This paper considers the potential adverse impact of such scale adjustment, however, on dilution, maintenance, flexibility, and other aspects of operations. It examines the mine production characteristics affected by increased equipment size and attempts to quantify the impact on the overall operation. Reference is made to data from operations that have experienced a variety of equipment size ranges changes over the last decade.

Jan 1, 2003

By Rilung Xu, Jerry C. Tien, Jian Liu

As underground mines become deeper and ventilation networs more complex, ventilation data becomes more complicated and voluminous, making timely ventilation planning and necessary changes more difficult. Oftentimes, ventilation engineers have to rely on special techques using graphs and schematic maps to carry out necessary ventilation planning [1, 4, 5, 6, 9, 10, 11, 12]. A different graphical method, similar to that reported by Taminago and Isobe [10], has been developed in China [13]. This method uses a two-dimensional diagram drawn from available ventilation survey results. It combines both the customary pressure-quantity diagram and ventilation schematic map, and can greatly expedite the interpretation of survey results, facilitate ventilation system design, short and long-range planning, and emergency planning.

Jan 1, 1993

By Takahide Wakamatsu, Junji Shibata

Complex polymetallic sulfide ore deposits occur in Tohoku district, northern part of Honshu island, Japan. The ore is locally called "Kuroko” ( black ore ) and is compactly composed of fine grained sulfide minerals of such principal metals as copper, lead, zinc and iron. Currently one of Kuroko mill plants is producing such concentrates as copper, lead, zinc, pyrite, barite, and clay minerals, mainly employing differential flotation techniques. This paper describes briefly the progress of techniques in Kuroko processing over the past thirty years and also the present state of Kuroko processing and its challenges to be studied and overcome in the future.

Jan 1, 1989

By Allen Pratt, Guy Deschênes, Mike Fulton, Hai Guo

Calaverite is a gold telluride species, with the composition, AuTe2. Calaverite is usually characterized by an exceedingly slow dissolution rate in a cyanide solution. Cyanidation of a slurry containing synthetic calaverite (P90 of 10 microns) was studied to determine the leaching kinetics and surface reactions. Alkalinity, dissolved oxygen, lead nitrate and sulphide minerals (pyrite and chalcopyrite) were among the parameters evaluated. The reaction products at the surface of calaverite were documented using X-ray photoelectron spectroscopy. High lime concentration with lead nitrate and injection of oxygen produced the fastest leaching rates. New gold leaching mechanisms were identified which appeared to be related to the parameters selected.

Jan 1, 2005

By Majid Ataeepour, Ernest Y. Baafi

High level programming languages such ass C, FORTRAN and BASIC have been used in the mining industry to simulate truck-shovel systems. In addition, some special languages for simulation such as GASP, GPSS, SLAM, PROOF and SIMAN are commonly used. The most recent simulation system ARENA uses graphical modelling approach as well as animation notion. In this paper, the main elements of ARENA required to perform a truck- shovel simulation and to view the simulation results by means of the model animation are presented. The layout of the haulage system including shovels, trucks and dump sites was generated using draw tool in ARENA. All the components of the haulage system were represented by graphical modules. Animation tool was used to depict the performance of the haulage system as the simulation progressed.

Jan 1, 1996

By T. H. Dubaniewicz, J. E. Chilton

The U. S. Bureau of Mines is investigating the application of fiber optic technology to methane and carbon monoxide monitoring. A methane monitoring system is described that is based on differential absorption of infrared light. It can detect concentrations as low as 0.2% and as far away as 2 km via fiber optic cable. The upper range is 100% methane. The system requires no electrical power within the mine so it should operate safely under mine disaster conditions. A hybrid carbon monoxide monitoring system is described that combines a low-powered electrochemical cell with fiber optic telemetry. Testing has shown the system can operate maintenance- free for several months.

Jan 1, 1992

By Heiskanen K., Koivistoinen P.

A common belief is that autogenous grinding suits itself only to certain oretypes. It is shown that properly designed autogenous grinding can be used even with very difficult ores with energy consumptions which are equal or lower than obtained with rod-ball mill grinding. The basic feature in the design is the large port grate developed by Outokumpu. The scale-up of the mills can be done on the basis of the base mill concept. It enables to compare different mill sizes and types. Simple scale-up equations are presented based on actual mill data and experimental work.

Jan 1, 1992

By Tanya Arsh, Thomas P. Kwiatkowski, Heather Marsh, Barry Doyle

The Big Walnut Sanitary Trunk Sewer Extension Project consists of two segments, the first a 10' excavated diameter tunnel in rock through the gas producing Ohio Shale formation and the second will be microtunneled through unconsolidated water-bearing deposits. Relatively large quantities of methane gas have been encountered in the Ohio Shale. In the softground segment, the sands and gravels contain large water storage capacity and contain shallow residential wells. This paper will present an evaluation of potential gas inflows in the rock tunnel, design considerations for contract documents preparation to inform bidders as to the volumes of gases which may been countered and design options for construction of an impermeable shaft excavation support system to insure residential wells remain in service.

Jan 1, 2001

Traditional finance theory recommends discounted cash flow (DCF) analysis as the tool to value mineral properties. Yet, the calculated values by this method are usually lower than the market value. Finance theory also advises us to develop an undeveloped project immediately if its net present value is positive. Most projects are, however, only developed when the economics are highly favorable. This paper uses insights from option-pricing theory to explain these divergences between market behavior and finance theory and presents simple modifications to discounted cash flow analyses that will lead them to produce correct valuation and development timing advice.

Jan 1, 1999

By P. Somasundarrtn, A. Sivakumar

Flotation of minerals is governed by many processes at the solid/liquid/gas interface, such as adsorption and precipitation of surfactants. In this paper, the basic principles governing these processes and hence flotation are discussed. Also, recent techniques such as fluorescence and ESR spectroscopy which have been used to study in situ surfactant adsorption and to obtain information on the structure of adsorbed layer are discussed.

Jan 1, 1987

By Heinz Hoberg, Fred Ulrich Schneider, Rudolf Diegel

The risk of contamination of dumped tailings and ground water by coal flotation reagents has been investigated by using the 14C-radiotracer method for adsorption and desorption measurements. The results indicate, that a high amount of the reagent components adsorbed on the tailings if there was no coal in the pulp. In coal flotation however a competitive adsorption behaviour could be observed, with the effect that only a low quantity of reagents adsorbed on the tailings. Mobilization tests showed, that only small quantities of reagents could be desorbed by rinsing water. Therefore the contamination of ground water should be low.

Jan 1, 1995

By L. R. Freitas, A. K. Resende, J. A. Oliveria, K. L. Gonçalves, L. F. D’Assumpção, L. R. Lage, J. D. Neto, F. Viveiros

Pará Pigmentos S.A. (PPSA) is an association between the Brazilian companies CVRD and CADAM, Mitsubishi Corporation of Japan, and the IFC (World Bank) created in 1992 in order to recover kaolin from Rio Capim deposit, northern Brazil. Commercial production at PPSA started in August 1996 using a process comprising mining and beneficiation at the mine site, pumping through a pipeline and drying/loading at the port site on the Amazon river estuary. Presently, all PPSA production is concentrated on 82% <2um, high-brightness coating clay shipped in bulk. In this paper, a detailed description of the development of PPSA beneficiation process is presented. The results of laboratory and pilot plant studies under- taken to develop alternative grades of clay, such as delaminated and calcined kaolins, are also discussed.

Jan 1, 1998

By C. L. Karr, D. E. Goldberg

This paper considers optimization of the design and operation of an air-injected hydrocyclone (AIHC) via a genetic algorithm (CAI. The AIHC is a mineral separating device, developed by the U.S. Bureau of Mines, that combines the selectivity of flotation with the capacity and simplicity of hydrocyclones. GA&apos;s are search procedures based on the mechanics of natural genetics. Computer results demonstrate the ability of a GA to rapidly locate design and operating parameters that improve AIHC performance. A computer model of the GA-designed AIHC predicts improved recovery over that currently being obtained with an AIHC in operation at the U.S. Bureau of Mines Tuscaloosa Research Center.

Jan 1, 1990

By Jaroslaw Drelich

This report briefly reviews the measurements and interpretation of adhesion forces measured between microscopic probes and substrates having micro- and nanoscaled roughness characteristics that were recently conducted at Michigan Tech using atomic force microscopy. The laboratory study concentrated on both rigid and deformable materials, with the probes larger than the size of roughness features of interacting surfaces. For such systems, a detailed surface characterization in terms of roughness parameters, asperity size and shape, and spacing between asperities, as well as analysis of deformation of materials is required. Analysis of the experimental data can be done with theoretical models, which are suitable for rough surfaces and therefore allows to normalize the measured forces. Alternatively, loading of the probe during adhesion force measurements can be managed properly to control deformations of the nano-scaled surface irregularities. Controlling the deformation reduces and even eliminates the effects of nano-roughness on the probesubstrate contact area, promoting conditions described by the contact mechanics models for the sphere-smooth substrate system.

Jan 1, 2005

By Pradip

It is possible to beneficiate low-grade phosphate ore slimes containing predominantly siliceous gangue by a combined selective flocculation-flotation scheme using commercially available reagents. The presence of clays, in particular, montmorillonite and attapulgite, has a disastrous effect on the efficiency of separation. Suitable remedies to overcome this problem are not yet available. Intensive R&D efforts are required in the areas of the design and synthesis of specific reagents, the effect of particle size, and the design of appropriate process equipment to carry out flocculation and flotation of slimes.

Jan 1, 1989

By Carl P. Maronde, William P. Barnett, Patricia A. Rawls

The commercial deployment of advanced fine-coal cleaning technologies depends on cost-effective approaches for efficient separation and ancillary operations in handling, dewatering, drying, and transporting coal fines. As a result of two solicitations under the High-Efficiency Preparation component of the Department of Energy Coal Preparation Program, several projects were initiated for testing and evaluation of emerging technologies and equipment that address operational difficulties associated with coal fines. This paper will update the status of those projects and discuss how the technologies they represent can ameliorate some problems associated with coal fines in today&apos;s preparation plants.

Jan 1, 1995

By H. Braun, T. Kind, K. Gloe, D. B. Dreisinger, H. Stephan, O. Heitzsch, G. A. Kordosky

Municipal garbage incineration processes with coupled wet flue gas cleaning systems generate effluents containing toxic heavy metals such as mercury, zinc, cadmium and copper. The separation of these metal ions from the obtained scrubbing solutions is possible using liquid-liquid extraction. Extraction studies has been performed both with commercial extractants Aliquat 336, di(2-ethylhexyl) phosphoric acid and novel chelating agents as acyl thiourea and lipophilic oxathiaaza alkanes. Advantages and disadvantages of the investigated extraction systems are discussed. The paper reports on the basic research as well as on the testing in a laboratory scale.

Jan 1, 1993