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By Charles D. Litton

This paper presents a description of the hazards of smoke from fires, the detectability of smoke using smoke sensors, and the operational characteristics of such detectors. It places in perspective the advantage that smoke detectors have over other forms of fire detection and also provides a discussion of smoke as a significant fire hazard.

Jan 1, 1992

By M. J. Scoble

There is no straightforward and systematic method for adequately measuring blast damage in on-going mining operations. This paper considers various techniques available for the measurement of blast damage, making particular reference to recent underground hardrock mine studies. This paper concludes by indicating the importance of understanding and accounting for geology and emphasizes the need for a robust damage-audit procedure.

Jan 1, 1997

By R. J. Lambert

The purpose of this paper is to discuss the application of mine design to the North DeLamar pit of NERCO's DeLamar Mine. Many discussions on mine planning and design focus on computerized mine modeling but neglect the final step of operating design development. Mine planning and design criteria used for the final layback in the North DeLamar pit are included along with a comparison of designed and as-built tonnages, grades and topography.

Jan 1, 1993

By Claude Bazin, Robert Grant, Mike Cooper

An analysis of the Pb recovery as a function of particle size was carried out for the CuPb rougher bank of a complex sulphide mineral processing plant. Results indicate that higher recovery may be achieved by optimizing the flotation feed size distribution. Simulation of the actual grinding circuit has provided guidelines to modify circuit operating conditions in order to improve product size distribution. Plant tests ar

Jan 1, 1991

By M. G. Yalçin

Marbles commercially known as the Nigde- white crop out in the town of Gümü?ler, around the Çalkama Hill within the Gümü?ler Formation of the Nigde Masif of Paleozoic age. Marbles sporadically occur within the masif, however its prevalent occurrence is associated with the Gümü?ler Formation. Due mainly to its intense fractured nature, the Nigde-white marbles are used as dimension stones, crushed stones and most recently micronized calcite. Insignificant portion accounts for block use through a few quarries.

Jan 1, 2005

By L. B. Guo, S. S. Peng

A hybrid boundary element-finite element model was formulated to model roof-bolt reinforcement of roof strata with bedding planes. This model was used to analyze the stress distribution around a rectangular opening, with variables such as opening width-height ratio, number of bolts installed, number1 location of bedding planes, in-situ stresses, etc. The most critical areas are identified, and the number and length of roof bolt required are then determined. Two case examples are illustrated.

Jan 1, 1991

By M. Kane, O&apos

BHP Iron Ore initiated research programs in January of 1995 to develop long term plans for decommissioning of the waste rock material at their Mt. Whaleback operation. More than 2 billion tonnes of waste rock were deposited during the past 30 years. Ultimately, the operators will deposit a total of approximately 5 billion tonnes in waste rock dumps constructed near the open pit. The Mt. Whaleback operation is located in a semi-arid climate adjacent to Newman, Western Australia, approximately 1200km north-northeast of Perth, Western Australia. The primary research program includes the development of technology for the long term performance of the waste rock dumps with respect to vegetation, slope stability, surface runoff, erosion, and water infiltration. This paper focuses on the design and implementation of a cover system to prevent water infiltration to the underlying waste rock. A laboratory program and the soil-atmosphere modelling completed to design the horizontal field test plots are described. The construction of the horizontal surface field test plots are discussed together with the field instruments installed to monitor performance. The key components of the instrumentation program are the design and installation of large scale field lysimeters to measure the unsaturated flow of moisture into the waste rock from the base of the cover layer. The cover system is designed to maximize infiltration during wet periods for subsequent evapo-transpiration while minimizing surface runoff. The result is a near zero net infiltration to the underlying waste material. A key feature of the design is the use of pit run waste material as the cover material. Monitoring is in progress and will continue for at least two annual wet/dry cycles. The optimum cover system should minimize the net infiltration of water to the underlying waste rock while maintaining physical and ecological integrity for long term performance.

Jan 1, 1998

By David W. Lillie, Pier A. Abetti

This paper reports on a study of the impact of fast growing new technologies on the market for copper over the next 15 to 20 years. The greatest threat is clearly the inroads of fiber optics on the traditional market for copper in communication cable. Opportunity areas identified include heat pumps, solar power and heat, desalination, electric vehicles and others. The overall impact of new technologies on copper is expected to be modestly positive if adequately encouraged by effective R&D.

Jan 1, 1986

By José Salim, T. V. Subrahmanyan

The occurence of primary stratiform and vein gold deposits in the Precambrian rocks of Northeastern Brazil is discussed. The stratiform deposits are related to clastic sediments (quartzites and conglomerates). The veins are associated with quartz and sulfides and are structurally controlled by shear zones. The gold was recovered for a long time by small miners. Developmental programmes for large scale mining are now envisaged. The recovery problems and gold economics are also discussed.

Jan 1, 1988

By Mark W. Springett

The sampling of precious metal deposits entails inherent problems due to the low mineral abundances, high mineral specific gravities, skewed grade distributions and wide ranges of mineral particle sizes. Sampling practices and precautions are discussed with particular attention to each of the tripartite stages of sampling - sample acquisition, sample preparation and sample assaying. Practical examples of approaches to the sampling problem are given and some examples of significant sources of error are provided from gold and silver deposits in North America.

Jan 1, 1992

By Simon T. Johnson, Robert J. Fowell

The application of roadheading and drag tool equipped machines requires an assessment of both cutting performance and tool consumption. Neither parameter can be assessed purely from compressive strength and tool consumption is often neglected, at a cost to the project. Results from in-situ monitoring show that a measurement of relative abrasivity using the Cercharscratch abrasivity test provides a basis for the assessment of tool consumption. This can be modified by also considering the effects of the machine specification and the rock mass quality.

Jan 1, 1986

By Donald W. Gentry

This article introduces mine planning as a complex process based on the quantitative and qualitative assessment of a myriad of independent and inter-or co- dependent variables. The interdependent variables of particular interest in this paper are those associated with mine planning activities that impact metallurgical processing plant performance and costs. These variables are identified and examples are provided to substantiate the argument that the magnitude and sensitivity of these variables must be formally assessed and analyzed to determine their potential impact on overall economics.

Jan 1, 1991

By J. W. Merks

Spreadsheet software is used to convert test results for drill core samples into borehole statistics such as volumes and masses of in-situ ore, metal contents and variances of metal contents. The properties of variances and the sampling variogram play a pivotal role, The additive of property of variances gives a sound scientific basis to the calculation of confidence limits for metal contents and grades as a measure of the risks associated with estimating reserves and resources.

Jan 1, 2000

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 A. Arik

The accurate estimation of mining-block grades continues to be a challenging task for ore reserve practitioners. The estimation method used and the variability of the mineralization in the deposit are two factors that affect the accuracy of the estimates. The objectives of this study are to determine how different estimation methods perform on a given deposit and to determine the impact that the nature of the mineralization has on the results. A comparison of several estimation methods for prediction accuracy is performed based on conditional simulation results.

Jan 1, 2002

By W. G. Courtney

The prevention of frictional ignition with a ripper-type continuous mining machine using conical bits was investigated in the laboratory using cutter-drum-mounted water sprays. Results indicated that frictional ignition during dry cutting of sandstone with conical bits was readily obtained even at low drum rpm, while wet cutting with a carefully-designed water spray nozzle located behind the bit substantially reduced the likelihood of frictional ignition. However, the orientation and operation of the spray nozzle is critical and involves almost no margin for error. A Lee-Norse 265 ripper drum has been modified to include durable water seals and is presently being field tested underground.

Jan 1, 1987

By J. R. Palmes

Flocculation of coal fines with varying degrees of wettability was studied under well defined hydrodynamic conditions. In this study, three coal samples were tested with three different flocculant types. The results revealed that flocculation depends strongly on both the coal surface properties and the type of flocculant used. A hydrophobic flocculant was found to be effective for hydrophobic and slightly oxidized coal, a semihydrophobic flocculant was found to flocculate, to different extents, all of the samples except the oxidized cool, and polyacrylimide flocculated all of the coals, which is a clear indication of its insensitivity towards coal wettability.

Jan 1, 1994

By C. R. Jenkins, G. S. Taylor

Three sedimentation ponds had their performance evaluated before and after installation of modifications. Each pond had a floating baffle installed, two had siphon outlets, and one had a floating outlet device. Baffles inhibited short circuiting, and the outlet devices retarded flow following a rainfall event and drained the pond, creating a large storage volume to maximize detention time. Total suspended solids and settleable solids tests were measured on samples of influent and effluent to evaluate pond performance. Particle size analyses were conducted on samples containing measurable amounts of solids. Performance improved in each pond, with baffles providing the major improvement.

Jan 1, 1987

By S. G. Haycocks, M. Karmis, C. Haycocks

Risk assessment is a primary factor in the decision to mine some near surface orebodies, such as limestone, by either surface or underground methods. Identification and quantification of risks demonstrate that environmental concerns are greater for surface operations than underground, and may include such factors as runoff, spoil piles, aesthetics, dust, and large site reclamation. Risk assessment also includes local public feeling towards surface and underground operations while considering the balance between environmental impacts and the economic effects of mining on the local community. A complete understanding of the risks involved permits a comprehensive and accurate comparison between the two mining alternatives.

Jan 1, 1992

By O. E. Etheridge Jr., R. A. Lowe, C. I. Basilio, J. M. Randolph, S. W. Sheppard

The low-shear viscosity of kaolin slurries is one of the principal characteristics that determine whether a clay can be utilized for paper and ceramic applications. In this work, the causes of high low-shear viscosity and methods for improving the rheological behavior of the slurries were investigated. The presence of fine-grained smectite impurities within the kaolin was shown to detrimentally affect the low-shear rheology of the slurries produced from these clays. It was also shown that mechanically working (i.e., pugging) a crude kaolin followed by desliming to remove these impurities can reduce the low-shear viscosity.

Jan 1, 2000