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By Robert C. Bates

Published information on costs of radon-daughter control in uranium mines was analyzed to develop estimates of the cost per ton for any level of radiation exposure control. All data were converted to 1967 cost of living index to provide a common analysis base. Results of the analysis show that the cost per ton increases exponentially as the radiation level is lowered. A linear relationship with the cost of living index is assumed, and equations and graphs are provided to estimate control cost per ton for any exposure control level and cost of living index.

Jan 1, 1981

By S. Bhattacharya, M. M. Singh

The Surface Mining Control and Reclamation Act of 1977 (SMCRA) requires under-ground coal mine operations to prevent "material damage" to renewable resource lands caused by subsidence. However, what constitutes material damage is not defined. This paper discusses the applicable criteria for agricultural lands, forests and grazing lands, surface water bodies, and ground water aquifers. Although data on the subject are limited, an attempt is made to present quantitative guidelines to distinguish between moderate and severe damage due to subsidence.

Jan 1, 1988

By William F. Kane, Eric C. Drumm

Rock slope failures in the Great Smoky Mountains of Tennessee are a continuing problem. A study of the geotechnical factors affecting such slopes was conducted in this geologically complex region. Seven rock slopes, five of which had undergone failure, were identified and mapped. Other parameters were mapped in addition to the standard geologic and geometric parameters. These were joint frequencies across and down the slope, and surface hardness from Schmidt hammer tests. Regression analysis on the various data revealed that Schmidt hammer hardness correlates very well with joint cohesion back-calculated from failure geometries. This approach suggests an alternative means for estimating joint strength.

Jan 1, 1986

By R. K. Mehta, U. Cetin

The Nevada Test Site is located approximately 100 km (65 miles) northwest of Las Vegas, NV. The site was primarily used by the Department of Energy for the field testing of nuclear weapons and has been contaminated by several million cubic feet of low-level radioactive wastes, heavy metals, explosive materials, and volatile and nonvolatile organics. The transportation and leaching of these contaminants are creating serious environmental problems. The purpose of this study is to examine pozzolan, a natural alumina-silicate mineral, as a possible replacement for the existing impermeable clay barriers. In the first phase of this study, radionuclide sorption characteristics of pozzolan were investigated. This paper presents the results of the adsorption tests for the target radionuclides.

Jan 1, 2000

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 Eric Forssberg, Benny Andreasson

The paper describes experiments to stabilize mineral processing waste materials for use in construction. Fine mineral processing wastes from various mines have been mixed with binders and compacted. As binders blast furnace slag and other materials have been used. Experiments have been made in laboratory scale and in large scale. The results have been evaluated by means of determinations of compression strength and the modulus of elasticity. The paper also describes some experiments in laboratory and large scale to use stabilized mineral processing wastes for back filling in cut and fill mining.

Jan 1, 1992

By K. H. McDaniel

Eight mine weather stations (MWSs) installed at the Waste Isolation Pilot Plant (WIPP) to monitor the underground ventilation system are helping to simulate real time ventilation scenarios. Seasonal weather extremes can result in variations in the natural ventilation pressure (NVP), which can significantly affect the ventilation system. The eight MWSs, which previously collected and stored temperature, barometric pressure and relative humidity data for subsequent NVP calculations, were upgraded to provide continuous real time data to the site-wide central monitoring system. These data can now be utilized by the ventilation engineer to create real time ventilation simulations and can indicate trends that assist in the prediction and mitigation of NVP and psychrometric related events.

Jan 1, 1999

By K. L. Kasperski, M. T. Ityokumbul

The effect of reaction conditions on the desulfurization of oil-sand coke residues was studied. The variables investigated were temperature, reaction time, heat transfer resistance and mode of caustic soda addition. The results show that oil-sand coke desulfurization increases with temperature, reaction time and heat-transfer rate. In an oxidative environment, coke combustion during molten-caustic leaching (MCL) commences at temperatures above 500 °C. The mode of caustic addition has no effect on coke desulfurization.

Jan 1, 1996

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 Richard R. Klimpel

This paper reviews the use of sulfide mineral collectors in industrial flotation practice. The approach of the paper is to characterize sulfide mineral collectors in a number of ways, including by chemical structure, by influences with different classes of mineralogy, by interactions with particle size, and by interactions with frother type.

Jan 1, 1999

By M. R. Bowie, J. M. Barker, J. S. Hingtgen

Techniques of testing perlite require a combination of art and science. The modifications made to the perlite Corp. vertical laboratory furnace include addition of instrumentation, flowmeters, vibrators, automatic feeders, and regulators. The basic testing sequence consists of expanded density, furnace yield, compacted density, percent sinkers, and compaction resistance. These tests are modified versions of those specified by the Perlite Institute. This sequence is designed as a preliminary evaluation of a material's suitability for horticultural-aggregate end uses rather than a detailed measure of filtration capability.

Jan 1, 1988

By F. Seymour

A modified three-dimensional Lerches-Grossmann (LG) graph tree algorithm that generates the complete set of nested maximum valued pits in a single run is presented. This modified LG algorithm looks at the relative strength (average value) of the branches (groups of blocks). Pointers are allocated and pruned until there are no members of weaker (lower average value) branches overlying members of stronger (higher average value) branches. The final set of strong branches arc listed in order of decreasing strength. The pits they represent form the maximum valued convex hull for a single-variable pit-limit parameterization. A description of the algorithm is given along with examples of lion it has been applied at Newmont.

Jan 1, 1996

By R. L. Pozzo, A. S. Malicsi, I. Iwasaki

The electrochemical nature of mineral-grinding media interaction in the wet grinding of one and two sulfide mineral ores was investigated with regard to the flotation behaviors of the minerals. Two iron sulfides (pyrite and pyrrhorite) and mild steel were used to represent the sulfide minerals and the grinding media, respectively. Galvanic currents in two- and three-electrode combinations under abrasive and non abrasive conditions were correlated with the floatabilities of these minerals under corresponding conditions.

Jan 1, 1991

By R. L. Lewis

The White Pine Mine is a large underground copper mine located in the Upper Peninsula of Michigan. A numerical ground water flow model of the White Pine Mine was constructed to evaluate potential engineering controls that would reduce the rate of mine-water discharge after closure. Of the passive controls evaluated, the placement of bulkheads within the mine workings was predicted to offer the greatest benefit, reducing the rate of discharge by as much as 35%.

Jan 1, 1997

By Daniel Hodouin, Antoine Berton

Mineral processing plants are monitored and controlled using measurements that are usually processed by on-line material balance calculation techniques. However, gross errors, due to sensor biases or failures, may corrupt all the process variable estimates. On-line gross error detection methods are required to ensure efficient mass balance evaluation. In the proposed approach, material imbalances and raw measurement corrections are tested by statistical techniques designed to detect and isolate sensor problems.

Jan 1, 2000

By R. Bhima Rao

Performing a magnetizing roast in a furnace or kiln is a well-established technology. However, the use of microwave heat for the magnetization of hematite in the beneficiation of ferruginous bauxite is a new approach. This paper reports on an investigation of this procedure, which is followed by comminution and magnetic separation. The results of this investigation indicate that a nonmagnetic product containing 80% A1203 and 2.5% Fe203 with a recovery of 80% can be made from a crude bauxite ore containing 55.9% A1203 and 5.6% Fe203. This product is suitable for refractory use. The mechanism is explained by the ability of the microwave radiation to heat specific points within the bauxite. These heat-specific points are at the location of iron minerals. In a reduced atmosphere, the microwaves promote faster conversion of the iron minerals to a magnetic phase, which improves the magnetic-separation process.

Jan 1, 1997

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 Deli Hu, Xiangze Shu, Cai Wang, Hongfu Liu

To detect the place and range of fire is one of the key technologies in the extinction of coal mine underground fire. A fire-prevention and extinction research team of Shanxi Mining College have successfully carried out a program detecting the place of fire with radon. In the past four years the authers have done the detecting work in several mines in Shanxi Province, such as Gujao, Xuangang Louan and Ningwu. The place and scope and the trend of underground fire of coal mine can be now exactly estimated. The data and information from detecting provide a reliable basis for drawing up the scheme to extinguish underground fire and extract mineral coal securely. The principle and method of fire detecting based on radon on surface, the data processing and analysis are discussed in this paper.

Jan 1, 1991

By J. -C. Roegiers, M. Thiercelin

Accurate toughness determinations are difficult to achieve in the case of soft or heterogeneous rocks. The existence of a large process zone ahead of the crack tip makes the determination of the apparent toughness crack length dependent, in the case of subsized specimens. In order to use practical size specimens, the authors propose a new toughness test, the Modified Ring Test, which pre- vents a largely developed process zone to form ahead of the crack tip. This test has also the advantage that its geometry is core-based. Numerical and experimental results are discussed.

Jan 1, 1986

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