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By D. S. Choi

This paper presents the results of geomechanics work applied to the longwall operation. The mining method was successfully adapted to US mining conditions resulting in an improvement in safety and productivity. The paper deals with various geomechanics problems associated with geologic and mining conditions.

Jan 1, 1987

By T. W. Camm

In this US Bureau of Mines report, mine and mill cost models are presented to make estimates of the cost to develop mineral deposits in the desert region of the southwest United States. Regression analysis was used to generate capital and operating cost equations for each model based on daily production capacity. These models are used for Potential Supply Analysis (PSA) studies by the Bureau, which analyzes the economic benefits of minerals in a region.

Jan 1, 1995

By Conrad Parrish

As originally conceived, this paper was to address the costs of environmental compliance, focus on environmental impact statements, and describe how those costs impact mining projects. The intent was to do wide ranging mathematical analyses to demonstrate the varying impacts on mining projects depending on their size, timing, return on investment and other salient project features. The initial portion of the numerical analysis necessary to this purpose was performed. The results showed a pattern of impacts familiar to the mining industry:

Jan 1, 1991

By E. Topuz

This paper compares the production rates of the conventional shuttle car/ belt conveyor haulage with battery or diesel shuttle car haulage by using computer simulators developed at Virginia Polytechnic Institute and State University. The haulage parameters evaluated in the analyses include discharge rate and capacity of a feeder located at the section dump point, and the number and capacity of haulage units. The results allow many decision points to be identified including the optimum number of haulage units to maintain production above that obtainable from a shuttle car/conveyor system.

Jan 1, 1982

By W. J. Whiten

A rule-based control system was developed for a 7-foot Hydrocone crusher with automatic set regulation, based on operating data collected in the field. When implemented in a plant PLC, the system was found to behave as predicted. Benefits included a significant reduction in the frequency of control actions, the incidence of power overloads, and the standard deviation of feeder speed, whilst maintaining crusher performance.

Jan 1, 1992

By Gordon R. Wicker, Willem P. C. Duyvesteyn, Robert E. Doane

A versatile acid leach process has been developed which is applicable to a broad range of oxide nickel ores. Inherent in this process are high recoveries of nickel and cobalt, as well as a relatively low energy consumption. These features extend the range of economic exploitation of laterite deposits to low grade limonites and to garnieritic ores not suitable for pyrometallurgical processing. Particular advantages can be realized in treating orebodies containing both limonite and garnierite and ores containing significant amounts of cobalt.

Jan 1, 1979

By Douglas W. Fuerstenau

Technological innovation is needed to meet the challenges that face the mineral industry because ores steadily become lower in grade, more complex in mineralogy, and must be processed in the face of ever- increasing environmental constraints and increased costs. How periodic innovation in mineral processing helped overcome the challenges that faced the mineral industry is briefly traced from antiquity up to the present time.

Jan 1, 1989

By Gordon E. Ager

A technique for the synthesis of mineral processing flowsheets from laboratory batch test data is described and examples of the application of the procedure are given. The procedure requires the collection of kinetic data, the optimization of the flotation time in each separation stage, then simulation of the material balance for a continuous circuit.

Jan 1, 1989

By G. Banini

A plug-flow model is described for the reactor mass balance of a typical AARL gold elution process. The model is in the form of a hyperbolic differential equation and was transformed using the method of characteristics. The transformed model was then solved simultaneously with models dependent on intraparticle surface diffusion and film transfer parameters. The solution was found to represent the experimental data for a modified form of the AARL elution. Correlation between the experimental conditions and the film transfer parameters estimated by the model are also presented.

Jan 1, 1998

By T. I. Probert, B. W. Burdett, L. B. Hales

Selecting a mineral processing control system from the multitude of offerings can be a formidable task. To assist the plant designer, the material in this chapter includes the advantages and disadvantages of different equipment types, configurations, and control strategies. Selection procedures are detailed, and the importance of each step in the design and selection process is explained.

Jan 1, 1986

By M. E. Kuchta

Research is currently being conducted at the Colorado School of Mines in the use of high-pressure water for scaling down loose rocks in underground mine openings. In addition to improved miner safety, the adhesion strength of shotcrete applied to rock surfaces treated with high-pressure water is also increased significantly, resulting in improved overall support capabilities of the shotcrete layer. Test results show an increase in adhesion strength by a factor of four on a concrete test wall cleaned with water at 21 MPa (3,000 psi) as compared to a surface cleaned at 0.7 MPa (100 psi).

Jan 1, 2003

By James G. Sampson

The discarded phosphatic clays from mining operations have historically been stored behind earthen dams for long periods of time before any reclamation was accomplished. In efforts to expedite the dewatering and reclamation of the clay ponds, the phosphate industry explored alternatives to conventional clay disposal practices. One alternative, employed by CF Industries, Inc., combines the clay and the discarded sand prior to disposal behind earthen dams. The sand encourages the clays to 'give up' trapped water more readily resulting in enhanced consolidation behavior. This paper provides an overview of the sand-clay mix process including the reclamation of sand-clay disposal areas.

Jan 1, 1992

By Jun Li, Marc Le Vier, Rong Yu Wan, Jan D. Miller

The hydrometallurgical treatment of gold and silver ores by ammoniacal thiosulfate solutions in the presence of a copper catalyst has been actively studied in recent years. Such a process strategy is very attractive due to the low toxicity of the lixiviant and the efficient recovery of the precious metals from difficult-to-treat ores. Important features of the ammoniacal thiosulfate system for the recovery of precious metals from various sources are reviewed in this paper, including leaching, metal recovery, and system stability.

Jan 1, 1995

By Arthur W. Darby

Heathrow Airport is owned and operated by BAA who are engaged in a major programme of expansion. In order to link the expansion of the airport in the west with the existing central terminal area, a twin bore, 8.8m outside diameter, road tunnel,1280m long, is being constructed. The tunnel drives pass over, with limited clearances, an operating railway tunnel, and pass under, with about one diameter cover, the airport taxiways and aircraft stands. Selection of the machine was heavily influenced by the need to minimise settlement.

Jan 1, 2003

By Frederick W. DeVries, J. Brent Hiskey

Cyanide has been recognized for about a century as the most effective reagent for processing gold ores. Cyanide leaching has been adapted to various metallurgical settings and continues to be improved. However, in recent years attention has been directed to alternative lixiviants for treating refractory ores and concentrates, and to the development of less environmentally controversial substitutes for cyanide. This paper reviews some of the reagents considered as alternatives to cyanide and focuses on environmental implications for using these newer reagents.

Jan 1, 1992

By Michael L. Nave

Mining belt conveyor elements are becoming larger and more expensive. Conveyor reliability requirements are rising. Conveyor condition monitoring can aid maintenance, reliability, and risk management in conveyor system operation. This paper examines the application of condition monitoring in coal mining belt conveyor systems. Types and form factors of condition sensors are described. Example costs are included. Suggestions for OEM developments are examined. Application problems are discussed. Two simple cost case studies are presented.

Jan 1, 2000

By Robert C. Bates

Background is given on the various equations used to describe diffusion and convective flow of radon in porous media. Bureau-developed equations for modeling diffusion and Darcy flow through multilayered porous media are described briefly, and examples of their use are given. Analysis results discussed include: The transient effect of pressure changes in different length models, time dependent flux changes in multi-layered models, and radon flux through pinholes in sealants

Jan 1, 1980

By George W. Poling

Designing optimal placer gold recovery plants requires a detailed knowledge of the size, shape and surface physical characteristics of the gold particles and the host alluvium in the pay gravel, sand or clay. Results of a recent pilot-scale study of the quantitative performance characteristics of riffled matted sluice systems are presented. For the appropriate non-coherent pay gravel-sand with medium-flat gold, simple sluices can recover gold at greater than 85% efficiency down to 100pm diameter. Alternatives to simple sluices are presented and discussed briefly.

Jan 1, 1987

By Song Xiaotian

In this paper the enviroment in which Tong Kuang Yu mine, China is developed is described. Geological and geomechanical environments which pose difficulties in the design and optimization of Block Caving are discussed. According to mine conditions, caving process simulation was carried out using Displacement Discontinuty Method and relationships between stress distribution .and undercut parameters were established in accordance with different undercut sequence. Based on simulation the influences of caving parameters on caving probability, drift instability and ore-draw control were analysed in order to optimize Block Caving Mining. On the basis of simulation and mathematical programming, the optimal sequence is proposed essential to satisfy the safety, production and other restrictions.

Jan 1, 1989

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