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If a fire occurs outby an underground coal mine section, the immediate safe evacuation of miners from the working section should always take precedence. Unfortunately, in many cases, the dedicated escapeways (escape routes) for the evacuation of the miners become contaminated by the byproducts of fire from the adjacent entries. The purpose of this paper is to present the ventilation-control process that would keep the escapeway free from contaminants and, thus, available for travel. A few scenarios of mine fires in longwall development panels are analyzed and discussed. To perform these studies, a mine fire simulator (MFS) was used. This (MFS) provides a dynamic representation of the fire's progress (in real time) and gives a color-graphic visualization of the spread of oxygen, combustion products and temperature of the gases throughout the ventilation system. Also presented and discussed are ways in which the MFS can be used as a training and teaching tool for miners and, particularly, for ventilation and safety specialists.

Jan 1, 1997

By V. R. Degner

Given: the process tonnage, performance objectives, and plant floor area, the paper will outline the metallurgical and machine hydrodynamic scale-up procedures for translating the lab flotation test results to the design of a full size flotation machine installation, including the machine number, size, and arrangement. Machine selection considerations for rougher, scavenger and cleaner duty, and special considerations relative to specific applications, will be summarized where appropriate. The value of kinetic modeling in quantitative metallurgical (lab to full size machine) scale-up will be reviewed considering a coal installation, and design information for additional applications such as copper, molybdenum, iron, phosphate, and potash will be discussed.

Jan 1, 1986

By A. W. Swanson

Iron carbide, containing 93.3% Fe and 6.7% C, is a tailor made feed for the electric arc furnace (EAF) and has recently gained worldwide attention as a possible replacement for premium quality scrap. With 38% of the steel in the United States being produced in EAFs, iron ore producers have an interest in becoming direct suppliers to the EAF industry. This paper explains the advantages of using iron carbide in an EAF and describes test work on the product and development work being per formed on engineering designs for a commercial plant.

Jan 1, 1994

By William R. Sharp

This paper describes a graphics station and graphics software designed specifically for use within the minerals industry. Through the graphics station, a user is able to recall maps for modification, display them on a color CRT, send the work to a plotter, and restore the work when finished. The engineer may use the system for the storing of data, per- forming engineering calculations, doing word processing, and performing general file maintenance. In addition, the system may be used to communicate with a mainframe computer for such purposes as: transmission of large data files, graphic 3-dimensional rotation of a mineral deposit or mine design, contouring of spacial data, and other data processing work.

Jan 1, 1982

This paper discusses how the link between design software tools and recycling models can be established in order to predict the recyclability of the car during the design phase, as well as to be able to apply design for recycling on a solid technological basis. Due to the complexity of the design of the car, optimisation of recycling can only be realised based on a sound technological basis, in which the dynamic and statistically distributed parameters affecting the recycling rate are described and understood. This paper gives a brief overview of the dynamic and recycling models, which are developed for optimisation of the recycling of the car and the calculation of recycling rates of the car in the design phase in view of EU legislation. Moreover the possibilities for modelling of shredding and liberation within the recycling system are discussed. The performance of experiments on a fundamental basis in order to collect statistically correct industrial data, supported by a closing mass balance, is referred to on the basis of a large scale industrial recycling experiment. It will be shown how design for recycling and environment can be supported by the sophisticated models as developed by the authors.

Jan 1, 2005

By T. V. Vasudevan

Floc properties such as density, size, size distribution, porosity, and shear strength govern the effectiveness of flocculation as a process for solid-liquid separation. The floc characteristics desired for removal of suspended solids by sedimentation or filtration, for example, are known to he different. In this study, an attempt has been made to evaluate the effects of various physical and chemical factors on the density and shear strength of the flocs.

Jan 1, 1990

By L. Donovan Clark

The term "powder factor" is almost universally accepted as the measure of the efficiency of a blasting program. It represents the economics of blasting since it designates quantity of explosive (thereby providing quality control in rock fragmentation) in terms of the associated volume broken. It is the wide use of this concept that explains the interest shown in an approach to rock blasting preferred by A. W. and Z. W. Daw* in a treatise on 3 blasting (1) substantiating its use in the form, Q = CVW3 for single shot hole, where Q = quantity of explosive lb Cv = blasting coefficient W3 = unit volume of rock It is obvious that the term Cv could also be called the apparent powder factor should the equation be written in the form, Cv = Q/W3 (lb per cubic unit). However, while the approach was ingenious** and the practical applications straightforward, their original, rather limited experimental work, along with certain assumptions, was questioned.

Jan 1, 1970

By James H. Vignos

An optical instrument designed for the on-line measurement of the size distribution of coarse particles (3-500 mm) being transported on a conveyor belt is described. Included is a discussion of the measurement technique, as well as test data verifying the legitimacy of the basic sensing approach. Field data indicating the instrument's ability to make useful measurements in an industrial environment are also presented. Applications in the mining and mineral industry, for which this instrument was orginally developed, are outlined, with particular emphasis given to the areas of crushing and grinding control.

Jan 1, 1979

By Graham E. Rawlings

Geotechnical investigations for underground projects are subject to a variety of constraints, including factors such as accessibility, geological complexity, thickness of oberburden and finance. As a result, the extent of geological data available for route selection and assessment of underground design and construction problems may vary between wide limits. It is essential that the data collected, the degree to which it is representative, and the confidence with which the problems can be anticipated, should be reflected in the type of contract set up and the way in which the contract documents are written. The paper addresses the methods by which investigations can be focussed to make suitable overall ground assessments for feasibility level studies. Subsequent investigations can then be objectively directed toward obtaining data on specific geotechnlcal problems or aspects which impact tunnel, cavern and shaft design and construction. The extent of investigations at the preliminary and design engineering stages must be closely related to the geotechnlcal surveillance and control during excavation. Fixed-price contracts necessitate a secure geotechnical data base prior to bidding, and the provision of that to the tenderers. By contrast, 'design-as-you-go' contracts minimize the geotechnical information needed before construction, yet require immediate assessment of the excavated ground for determination of support requirements and payment category.

Jan 1, 1983

By Val Ness, Leonard Harris

Mentoring is defined as close counseling by an experienced and objective advisor within the industry. It is one aspect of attracting the best candidates into the minerals industry, holding their interest, and encouraging stable career growth. By encouraging proper mentoring practices, we foster strong careers, we transmit important wisdom to the next generation, we fortify the industry with better talent, and we encourage the best possible advocates for the minerals industry. This paper illustrates the consequences of poor mentoring, offers an example of positive mentoring practice at the college or university level, reviews some guidelines for stable and fruitful mentoring, and proposes a plan to spread appropriate mentoring practices. Authors' note: The use of masculine pronouns is for convenience and simplicity only. Our best engineers and managers come from both genders, and the authors intend no slight to either one.

Jan 1, 2001

By Louis W. Cope

The Compañía El Zapote Yacimiento Y Minas, S.A. has an ore body containing 650,000 tons of 0.185 oz/t gold ore in Mexico. Metallurgical testwork has been done to determine the response of this ore to several possible processing schemes. The paper describes the rationale for selecting the Silver State Mining Co. methods in Colorado. Plans for developing the mine and building the treatment plant are described in detail in the paper. Estimates of capital and operating costs are included.

Jan 1, 1984

By Zhang You-di

A comprehensive model has been set up for surface mine long range planning. It is a system simulation model based on the oriented graph theory. Via this model, a series of mining results such as mineral and waste volume, mineral quality, mining intensity, material haulage distances, dumping area parameters and mining coat for different mining alternatives, can be derived and optimized. This model has been applied to 37 mining alternatives in several surface coal mines and proved mathematically correct and results reliable.

Jan 1, 1986

By W. Z. “Ben” Wu

The investigation provides a method of efficiency evaluation among several kinds of tools employed to cut different types of rocks. A ballistic test stand incorporated with a modified Hopkinson bar was used to simulate a percussive drilling tool. An Apple IIe microcomputer was employed for high speed data acquisition and numerical analysis. A newly developed method for remote monitoring the rock-tool interaction, including contact force, bit penetration and energy transmission,is presented in the paper. Theoretical predictions and experimental results appear in faily good agreement

Jan 1, 1986

Research has determined that ground control interaction problems in mining over a previously mined seam occur primarily in the tension zone created at the edge of the subsidence trough, and in areas above lower seam remnant pillars. Based on empirical and analytical studies, planning options for improving conditions on the upper seam have been developed to optimize extraction while minimizing the negative effects of seam interactions. These options include prediction of potential upper seam damage, guidelines for minimizing inevitable negative interaction effects, and recommended opening and pillar sizes, shape, and orientations, as well as design and planning procedures.

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 H. E. Goetzman

A cooperative research project supported by the taconite industry and the Minnesota DNR was undertaken to establish quality standards for carboxymethyl cellulose (CMC) based organic binders. The objective of this study was to identify the effect of CMC quality parameters such as degree of substitution, molecular weight, and purity as well as the effect of inorganic extenders such as sodium carbonate on performance. These factors have been evaluated by green-ball testing with two taconite concentrates followed by pot-grate tests. Balling tests with bentonite and Peridur were conducted to provide baseline data. At a constant DS the molecular weight as measured by viscosity had the greatest effect on green-ball drop strength. Dry-ball compression strength was most dependent on CMC addition rate and sodium carbonate content. DS was not found to have a major effect on green-ball quality for medium molecular weight CMC.

Jan 1, 1988

By M. C. Rockwell, G. F. T. Lay

Promising placer gold exploration sites offshore Lunenburg County are drowned pre- and post-glacial river channels and auriferous glacial tills. Gold values up to 5.67 9/m3 have been encountered in the vicinity of the Ovens Peninsula offshore Lunenburg County. Moderate gold values associated with notable amounts of heavy minerals were reported from various other exploration sites in this area. This paper highlights the major geological and gemorphological features for placer gold depositions in southern Nova Scotia. The past to present gold exploration activities nearshore and offshore Lunenburg County are summarized and potential areas for placer gold identified.

Jan 1, 1988

By G. T. Adel, W. Z. Choi

In previous work at Virginia Tech, a population balance-model describing the simultaneous processes of size reduction and mineral liberation has been developed. Experimental verification of this model, however, has been limited to a binary mineral system containing only one composite particle class. When considering multiple classes of composite particles, estimation of model parameters becomes much more difficult. In the present work, a procedure for estimating model parameters for a multiple-composite- class model has been developed. Emphasis is placed on direct experimental determination of these parameters. The physical significance of the breakage rate function and the liberation function in characterizing the liberation process is also discussed.

Jan 1, 1987

By A. R. Zambrano

Equations for power draft, capacity and work input for predicting the performance of industrial grinding mills are derived based on torque measurements using a laboratory instrumented mill. These derivations are based on mechanical principles and on the first-order kinetics of the grinding process. Rittinger's, Kick's and Bond's laws express work input as work index (Wi) times a particle size function. It is proposed that these laws are only particular cases of more general expressions having the particle size function raised to an exponent, i.e., the work exponent (We). Case studies illustrate the excellent prediction of the Wi - We models compared to the three mentioned laws, and, from the data, the corresponding general mill-sizing equation is derived. Key words: Grinding mills, Comminution, Work index, Mill sizing

Jan 1, 2003

By Alan P. Cook

Methane levels have been measured around continuous miners and compared with computer simulations of methane flow. A multi-channel data logger, reading continuously from six methanometers, has shown methane levels to vary at different positions around a continuous miner, with the cutting drum and the immediate face area not necessarily recording the highest concentrations. Methane levels in the driver's cabin are generally low compared with the return side. Computer simulations, using computational fluid dynamics, have been supported by the measured data, and have shown that methane behaviour within the first few metres of the face varies considerably for different bord and pillar development stages. Methane is diluted rapidly to acceptable levels, but the distance required for this is extended when ventilation flow to the face is restricted.

Jan 1, 1995