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By J. R. Mattern

The engineering geology of the Rio Tinto Borax Boron Mine creates challenges in providing practical slope design recommendations to mine planning engineers. Low strength sedimentary units interbedded with very low strength lakebed clays surround the orebody. Faulting has offset and juxtaposed these units into variably adverse orientations, while groundwater is compartmentalized both vertically and horizontally within fault blocks. A collective program of geologic data collection, geomechanical strength testing, geologic modeling, slope depressurization, confirmation of underground stope locations, and documentation of slope behavior provides vital information for design investigations and sensitivities. Analysis results lead to risk assessments and operational procedures that add value to the business by optimizing slope configurations and minimizing risk.

Jan 1, 2004

By G. S. Dobby, N. J. Contini, S. W. Wilson

Scale-up and simulation of flotation columns requires construction of mathematical models which employ, as a minimum, rate constants for quantifying particle recovery in the collection zone as well as split factors for quantifying froth zone performance. To date, measurement of these rate parameters has proven to be difficult, due to the interdependent nature of the collection and froth zones. This paper describes a technique for making these measurements. The method requires recovery data from two modes of operation: countercurrent and cocurrent. In cocurrent flow slurry is fed at the bottom of the column and tailings are withdrawn a short distance below the froth interface. Countercurrent mode is conventional operation. The critical difference is that particles which are dropped out of the froth in cocurrent mode are immediately lost to tailings, while in countercurrent mode the particles are subjected to recollection. Fitting of the measured recoveries to the equations that describe flotation in the two modes yields rate constant or recovery values for both the collection and the froth zones.

Jan 1, 1988

By R. K. Mehta, G. T. Adel

A review of the literature reveals that methods for simulating the coupled behavior of size reduction and liberation are limited to binary mineral systems containing one composite particle class. The aim of this paper is to describe the development of a mathematical model to simulate such behavior for binary and ternary systems containing multiple classes of composite particles. A modified Levenberg-Marquardt algorithm and a finite difference Jacobian are used in conjunction with the developed model and a set of constrained equations to estimate all kinetic parameters. This estimation scheme is validated far a binary ore (sphalerite-dolomite) with five composite particle classes using experimental data.

Jan 1, 1991

By R. Simon

Strain-burst phenomena are generally characterised by sudden releases of energy in a volume of highly stressed rock. Strain bursts are encountered in situations such as crown pillar bursts during cut-and-fill mining, face bursts at development headings cord floor bursts in deep shaft sinking. This paper describes a simple two-dimensional linear elastic FE modeling approach that leads to the calculation of the energy-release rate (ERR) and the total energy storage rate (TESR) in the rock-mass around the openings. The merits of using such energy parameters in the analysis of strain-burst problems for identifying areas of high energy release/storage are discussed through a case stud v. However, much site-specific back analyses are needed to better understand how strain bursts and energy parameters are interrelated.

Jan 1, 1999

By Kerstin Malmqvist

Simulation technique has been used for a feasibility study of a deep exploration project for massive, sulphides in an old mining district, the Skellefte field. An interactive computerized mathematical model of an ore field and a drilling procedure has been constructed. It is possible to represent varying geological structures. The model also takes in consideration economical factors such as drilling costs and ore values. On this model Monte Carlo simulations and probability calculations are done in order to estimate the outcome of different drilling strategies under varying geological assumptions. Under the specific conditions of the well known Skellefte field, it is found to be possible to even calibrate the mathematical model.

Jan 1, 1979

By David Sugden

Intense, tropical weathering of Cretaceous-Tertiary sediments has developed similar laterites in distant areas of the Amazon Basin. In two areas, Trombetas and Paragomina s, bauxites of commercial potential arc found. The bauxite comes mostly from the lower horizon of the three component laterite. The laterite is overlain by a clay cover, possibly an integral part of the weathered profile. The laterites are found on almost flat plateaus with individual areas of up to 80km2. There is a close relationship between the morphology and the ldterites. The process of lateritization is allegedly Pliocence but probably continues today.

Jan 1, 1984

By J. M. Mutmansky, Aiping Wang

This paper outlines the patterns of methane emission in both longwall and room-and-pillar operations and discusses the effects that these patterns have on the decision as to whether the methane is most economically handled by ventilation alone or by means of a methane-drainage system in addition to ventilation. The costs of handling the methane in the ventilation system and the costs of implementing the methane-drainage system are discussed, as well as the costs related to the production of coal. The important issues of production slowdowns and gasouts are also discussed, as well as the proper response of mine management to such a situation. Suggestions concerning the keeping of production records related to methane problems are made, and the justification for more intensive economic analysis of coalbed methane extraction and utilization is discussed

Jan 1, 2000

By Roman Pyrih, Jim V. Rouse

Because cyanide is a naturally-occurring chemical, geochemical and biogeochemical mechanisms exist to retard or attenuate the movement of cyanide and its compounds in the subsurface and to degrade such compounds into low-hazard reaction products. The attenuation capacity of subsurface earth materials can be measured, predicted, and enhanced by simple and inexpensive procedures. The paper describes methods of testing the geochemical and biogeochemical attenuation capacity of the subsurface and offers general suggestions for methods of enhancing such capacity. It also presents examples of data which documents such attenuation.

Jan 1, 1991

By Y. Luo, S. S. Peng

Based on the concept of slope-stability analysis, a formula for determining an important parameter required in the mathematical model for the prediction of mining subsidence in hilly terrain is proposed. The slope geometry and the physical and mechanical properties of the soil at the surface of the natural slope can all be considered in the formula. Incorporation of this new formula into an existing mathematical model provides an integrated approach for the study of ground movement in hilly regions.

Jan 1, 2000

By Ing. Alois Adamus, Ing. Václav Pošta, Ing. Lubomír Hájek

This paper reviews experiences connected with the use of nitrogen in the Czech coal industry. Special attention is focused on the first use nitrogen In the Czech Republic, it is probably the first case of fighting a mine fire using nitrogen in all the World. Discussion dwells on the present-day use of nitrogen, its sources, consumption, technological equipment, and the theoretical evaluation of nitrogen flushing.

Jan 1, 1995

By James W. Martin, Brad H. Droegmiller

As construction projects continue to get larger, greater demands are placed on systems to provide higher production rates at reasonable costs. This paper shows the application of dozer-trap loading versus other methods of moving bulk materials. Most conventional methods employ multiple types of heavy equipment to accomplish a single task. Trap loaders fed by dozers and discharging onto overland conveyors offer an alternative/economical means of high volume bulk material movement. This paper will discuss the process of trap loading to overland conveyors.

Jan 1, 1998

By Mengxiong Guo, Xuxin Shao, Yong Bao

In the paper, the adsorption properties of dissolved ions on the surface of collophane and dolomite are studied using zeta potential measurement, ESCA and UV adsorption spectrum both in distilled water and in the supernatant of each other. The effect of dissolved ions on the flotation separation of collophane and dolomite under SCO depressant and oleate is discussed on the basis of above analyses.

Jan 1, 1993

By S. Mason

Many organizations are realizing that continual improvement in health and safety relies on addressing the potential for various forms of human error. Of these, rule violations are often the most frequent form associated with accidents. These occur when an individual (or individuals) deliberately contravenes established and known safety rules. They have been associated with up to 90% of the accidents and other incidents in some industries, and yet they rarely receive the systematic attention they deserve in the promotion of safety. This paper presents underlying motives that cause violations. These can vary significantly from mine to mine and from job to job. Managers need some measure of the attitudes of the violators to determine the underlying motives behind the violations if they are to determine effective strategies for promoting safe behavior. Questionnaires form the starting point to address attitudes and the motives behind rule violations. The choice of the most suitable questionnaire, how- ever, will vary from organization to organization. Guidelines on the choice of questionnaire are offered.

Jan 1, 2000

By K. A. Natarajan, M. K. Yelloji Rao

The effect of galvanic interactions among sulfide minerals such as chalcopyrite, galena, and sphalerite in the presence and absence of a grinding ball material on the flotation recovery of chalcopyrite has been studied. X-ray photoelectron spectroscopy (ESCA) studies were carried out to identify the reaction products on the sulfide minerals after different apes of galvanic interactions. Galvanic contact with active minerals such as galena and sphalerite, either alone or together, significantly affected the floatability of chalcopyrite mineral, such an effect being more severely felt in the additional presence of a grinding medium as well as oxygen. Surface analysis studies revealed the presence of oxyhydroxide species of iron on all the sulfide mineral samples which were in prior contact with the grinding medium. The formation of such oxyhydroxide species of iron was found to be dependant on the relative electrochemical activity of the mineral. Probable electrochemical reaction mechanisms are discussed.

Jan 1, 1990

By D. R. Spears, C. E. Jordan

In an effort to improve flotation efficiency of the domestic minerals industry, the US Bureau of Mines conducted research to measure the improvement provided by fine bubbles on the flotation of fine-sized particles (minus 20- µm, minus 625 mesh). The turbulent velocity distributions of the fluid within the flotation cell were measured as a function of time and position and used to increase the precision of a fine-particle, turbulent-flotation model. For the mineral system tested, improved flotation response was obtained in the laboratory testing with small bubbles and intense agitation. These results matched the model's predicted response.

Jan 1, 1991

By S. Page, R. Bhaskar

The development is described of a real-time tracer gas sensing system for use in fell-scale laboratory studies of air flow behavior around mining machines. A semiconductor sintered tin-dioxide gas sensor is used for gas analyses. A data acquisition and analyses software specific to the sensor characteristics was also developed as part of the system. The system permits the study of transient behavior and assists in obtaining a better understanding of the movement of air around mining machines and in the study of the effect of potential airflow modification devices on the dust exposure of face personnel. It seeks to replace the current method of using a centralized infrared gas analyzer that polls several sampling points using an array of solenoid valves and gas line purgers. The polling results in a significant time lapse between the first and the last set of readings. The system described in this paper has the advantages of real-time sampling and safe operation.

Jan 1, 1992

By Samir Kumar Das

Presently Geographic Information System (GIs) is gaining wider acceptance id appreciation in various resource management surveys, generation of various thematic maps, various scientific investigations, environment assessment, disaster management, etc in India but they are general in nature. A huge number of Global Positioning System (GPS) based "Total Station" are playing good roles in India for accurate and quick surveying . The GPS based real time Mine Management and Truck Dispatching System for optimization of productivity is being installed in the Panchpatmali opencast bauxite mines of India. This paper dealt in depth on GIs and GPS and their present roles in the Indian mining scenario.

Jan 1, 2002

By Richard A. Brown, Robert D. Norris

By-product metals can be a significant source of revenue for a mining operation if their recovery can be accomplished without negatively impacting primary metal recovery. The main problem encountered in separating primary and secondary metals is to selectively control the solubility of the individually important metals with¬out affecting their ultimate recoverability As a class of hydrometallurgical chemicals, peroxygens have a versatility which permits the selective recovery of individual metal species. Peroxygens function as more than simple oxidants. They are effective solubility control agents and have proven utility in complexation, precipitation, dissolution, extraction, oxidation and reductive processes Peroxygens have been used commercially to recover by-products vanadium, uranium, molybdenum, and cobalt and have proven experimentally to recover rhenium, gold, silver, manganese and zinc

Jan 1, 1983

By Alfred Jr. Petrick

Modelling of cash flows and calculation of net present value of rate of return over the expected life of a mine/processing unit continues to be the accepted basis for mineral investment decision-making. The computer and spreadsheet programs have greatly improved ability to perform sensitivity and risk analysis, hence our ability to deal with key analytical problems. These problems of cash flow analysis result from the necessity of forecasting an uncertain and risky future. Cash flow models begin with the critical assumption of a "design basis", then integrate all of the variables relevant to the investment decision including forecasts of price, cost, taxation, financial conditions, and company strategy. Alternate "scenarios" portray possible future outcome of the investment decision. The potential for straying from reality is enormous. The computer has eliminated the time consuming hand calculations from the cash flow analysis, but the analyst still struggles with the risk of trying to predict "how the project will really turn out".

Jan 1, 1991

By A. S. C. Owili-eger

An efficient state-of-the-art dynamic model to simulate and predict the rate of water production in longwall coal mining operations was developed as a tool for mine planning purposes. The model can also provide an estimate of any potential resultant hydrogeological impacts of an operation via an array of element-specific single-valued parameters referred to as the field rating indices. The computational procedure was designed to fully exploit the benefits of hydrogeotechnology and use a combination of conceptual, physical, empirical, and numerical approaches to define, characterize, analyze, and evaluate flow controlling properties of fractured rock systems. The model presented here provides a dynamic prediction method for highly fractured flow; a practical tool in mine and water control planning; and a cost-effective means of assessing, based on the best available technology, the impacts of mining on the water resources within a mining environment to satisfy local and federal regulatory requirements. Unique features include consideration of laminar and non-darcian flow domains in double-porosity-pressure hydrogeological media.

Jan 1, 1990