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The operation of quarries for the production of crushed stone and aggregates, depends heavily on rock blasting efficiency, which usually represents a major share of total production costs. After investigating the causes of this situation, a series of technical aspects have been detected, and they are described for the purpose of contributing to the minimization of costs, which also reduces the effects of blasting on the environment. Utilization of empirical design methods, of inadequate explosive types, and of erroneous drilling pauems with respect to rock properties, are the main factors to be corrected, as a consequence of poor engineering criteria, with scarce use of computational methods and field instrumentation. Several concepts of blasting optimization are pointed out, and their application to industrial operations in a Portuguese limestone quarry indicated clear trends for the reduction of production costs, as well as some of the deleterious consequences of blasting on the environment.

Jan 1, 1990

By Claude Hubert, Robert Sansfaçon

"The Malartic gold camp includes the Malartic Gold Fields, Barnat, East-Malartic, Canadian Malartic and Sladen mines. From 1935 to 1984, these mines have yielded 212 403 kg of gold. They occur within a 900 m wide belt of highly sheared, dislocated and faulted volcanic and sedimentary rocks (Piché and part of the Pontiac groups) herein named the Malartic Tectonic Znne (MTZ). The zone trends WNW-ESE and separates two lithotectonic sedimentary domains, the Cadillac to the north and the Pontiac to the south. The sedimentary domains are characterized by their coherent fold generations consisting of open to tight reclined and recumbent F1 folds that have been refolded into series of asymmetric upright F2 folds. A flat-lying schistosity (S1 ) and a vertical pressure-solution cleavage (S2) are ubiquitous throughout. Discrete sets of brittle and brittleductile faults are synchronous and parallel to each of these two fabrics.The MTZ trends N320° in the northwestern sector of the town of Malartie, changing to N2800 at its easternmost extremity. The Malartie and Sladen faults constitute its northern and southern boundaries respectively. These two faults also bound another set of faults oriented N305°. Throughout the MTZ, the faults at N280° and N320° and those at N305° outline a series of anastomosed motifs that constitute the principal structural feature of the Malartic district. Locally, a fourth set of minor faults at N065° combines with the other three prominent sets. All these faults have disrupted the gold-bearing volcanic, sedimentary and intrusive rocks encountered throughout the MTZ.The MTZ comprises numerous lozenge-shaped blocks of komatiites and basalts or greywackes and black shales which are cut by disjointed dikes, sills and small intrusions of felsic and mafic rocks. The latter includes gabbro, diorite, lamprophyre, monzonite and pegmatite. They frequently fill conjugate sets of fractures. In some areas, they are clustered into coalescent intrusions. The present morphology of these intrusive bodies( cube, chocolate-tablet boudin, parallel epiped and cigar) is not representative of their primary forms but the result of late shearing and faulting indicative of a major tectonic event subsequent to their emplacement. The intrusions were injected during a brittle stage of deformation related to the F1 folding but prior to the development of the F2 folds and subsequent tearing and shearing by late brittle and brittle-ductile faults . The ultramafic and mafic rocks are intensely altered to serpentine, tremolite, actinolite, carbonate, biotite, hematite and pyrite according to the nature of their proto/it h. In the vicinity of the MTZ, all lithologies exhibit mineral assemblages indicative of the upper greenschist or lower amphibolite facies of metamorphism.The structural evolution of the MTZ involved superimposed folding, shearing, transposition, mylonitization, brittle and brittle-ductile faulting. Each lenticular motif results from the combined effect of conjugate sets of shear zones that outline lozenge-shaped blocks where strain markers indicate different strain states from cores to margins. Bedding in ultramafic flows and/or sedimentary rocks is either NW-SE or NE-SW within the blocks but, in the vicinity of the Malartie and S laden faults, it has been rotated to become subparallel to the faults.Ore shoots are most commonly associated with altered and deformed bodies of diorite and monzonite, or some mafic and ultramafic schists and, at the Canadian Malartic, Sladen and East Malartic mines, with metasedimentary rocks. The shoots occur in close proximity to the various faults of the MTZ but the gold itself is intimately associated with pyrite, biotite and carbonate in halos bordering fractures crisscrossing the different host rocks. The density of fractures and the width of their altered zones have been significant parameters in the production of economic ore shoots. Grains of gold are visible in some veins of quartz a"

Jan 1, 1990

By Kobayashi M

Particulate chalcopyrite samples (78 ~ 98 mole per cent chalcopyrite, screen size fraction from 710 to 250 µm) were prepared by crushing and sieving lump ore samples from 12 locations in the Mt Isa Mine. Measurements of thennoelectric power (which does not involve the passage of a current) were made using a packed bed that was compressed by loading with a weight and placed in a temperature gradienL Details of the apparatus are described.The effect of particle size was investigated by preparing 12 fractions, with mean particle sizes ranging from 605 to 2.2 µm, from one of the ore samples. Values of thennoelectric power decreased with both increasing particle size and loading pressure; however it remained fairly constant for particle sizes above 80 µm, when loading pressure exceeded 3.3 MPa.Measurements of the chalcopyrite samples gave an average value of -260 JlV/K (-248 ~ -268 µV/K) for nine samples and about -290 µV/K for three samples, showing that these samples were all n-type semi-eonductors.

Jan 1, 1990

By T. Warren, R. Pender

"Significant strides have been made during the past decade to integrate the traditionally separate administrative functions of financial management, materials management and maintenance management.In 1983, Key Lake Mining Corporation (KLMC) brought on-stream one of the most technologically advanced mining operations in North America. There was a requirement to support this new facility with state-of-the-art management information systems.This paper will discuss the development and evolution of the corporation's computerized information systems with specific emphasis on the utilization of computer systems to assist maintenance personnel in performing their work activities:Note: In August of 1989, the administration and operation of the Key Lake Mine was assumed by CAMECO - A Canadian Mining and Energy Corporation.IntroductionThe Key Lake Mining Corporation was incorporated in 1979 and operates a $500 million uranium mining and milling complex located in northern Saskatchewan.The feasibility study and environmental impact statements for the Key Lake Mine were submitted in 1979and in August of 1981, following a public inquiry, approval to proceed with construction was granted. Ore processing commenced in October of 1983 and during 1984 a total of 10.4 million pounds of uranium oxide (U3O8) was produced. In 1987, an annual production of 13.5 million pounds was achieved clearly establishing Key Lake Mining Corporation as the world's leading producer of uranium oxide. Current ore resources are expected to extend production of the Key Lake facility into the year 2000."

Jan 1, 1990

By G. J. Goldberg

Through the early 1980's, surveying at Bingham Canyon required a great deal of repetitive and manual work. The advent of total station surveying equipment provided an opportunity to improve the speed and accuracy of surveying work while reducing manpower needs. An evaluation of total station systems and their ability to meet the surveying requirements of Bingham Canyon culminated in the purchase of a total station system as the mine re-opened in 1986. This paper presents the procedure for evaluating, implementing and using the total station survey system at Bingham Canyon.

Jan 1, 1990

By William Cruger

OUTLINE SUMMARY A. Brief Description B. Characteristics 1. Can be highly cost effective 2. Restricted in usage 3. Political Controversy 4. Volume of Transactions 5. Users C. Mechanism 1. Five steps D. Investor issues 1. Application 2. Restricted usage 3. Discount 4. Formal or informal process 5. Restricted benefits 6. Recompense 7. Window of opportunity THE VARIOUS PROGRAMS1 A. Brazil B. Chile C. Venezuela D. Argentina E. Mexico USAGE IN THE MINING, METALLURGICAL, AND PETROLEUM INDUSTRIES

Jan 1, 1990

Indonesia remains relatively unexplored by modern methods. The great expectations created by the rush of companies taking up Contracts of Work over large areas during the epithermal gold/ring-of-fire boom (1985-7) have not been fulfilled. This is not necessarily a reflection on the prospectivity of Indonesia; on the contrary, many of the hopeful companies were,, under-staffed and under-financed to overcome the physical and logistic problems of exploring virgin jungle.After the stock market crash of 19th October, 1987, many of the weaker companies were unable to sustain their programs or to arrange farm-outs, and they have subsequently relinquished their tenements. In some cases, little or no field work has been carried out so that many areas remain untested. This poor performance will ensure much more rigorous scrutiny of future applications by the Indonesian authorities.

Jan 1, 1990

In the minerals industry allocating capital for setting up a new project or for upgrading an existing facility usually requires that a compromise be found between the initial cost of equipment, its operating performance and on-going operating costs. To maximise the return on the investment usually requires that various possible combinations and layouts of equipment be assessed. This task is both difficult and time consuming. Computer simulation can be used as a means of determining the expected operating performance of a range of alternate equipment configurations. Simulation is a particularly important technique for analysis as it is one of the few approaches that allows the analyst to take into account the variability inherent in a mining process. While computer simulation is a well established technique its use, until recent years, has been limited to large organisations with access to substantial computing facilities. However, with the current availability of low cost computing platforms combined with easily understood animated displays, simulation is now becoming more widely used across the industry.

Jan 1, 1990

By Reha Ozel

The stability in longwall faces depends on the interaction beman the roof strata, face supports and floor strata. The load distribution on the other hand, depends upon relative stiffness of the three supporting elements namely, the coal face, support and gob. Therefore, in defining support requirements, it is particularly important to analyze the strata loading, the face convergence and the controlling mechanism provided by supports. The controlling mechanism however, depends on the type and characteristics of supports used in long- wall faces. The design guidelines presented in this paper have bean developed based on a number of strata control oriented projects carried out in Turkey, load and convergence measurements carried out in 10 longwall faces, in Zonguldak Coal Region, and procedures given in literature. Evaluation of load and convergence measurements, and analyses of face supports were carried out by means of a computer program, called L0NGWAI.L-MEW, developed by the authors. The output of the design analyses include the following: (1) estimation of support capacity for roof supports namely; individual hydraulic props, chock-type power supports and various types of shield supports, and (2) analysis of loading conditions and response of shield support components in terms of stability and structural integrity.

Jan 1, 1990

By D. A. Baker

This report describes the elemental characterization of chromite and related materials at the Bureau of Mines, Albany Research Center. Analytical methods for determining the major constituents, representing extensive experience, refinement, and development, are described and fully annotated. This presentation should allow other laboratories to use these methods and obtain comparable results with a minimum of time needed for familiarization with individual methods.

Jan 1, 1990

By A. W. Khair

This paper presents an engineering approach to solve a complex ground control problem at reduced cost, allowing the mine to be operated safely and economically. The mine has experienced serious and complicated cutter roof problem in the entries. This cutler roof problem has delayed the advance of the entry development considerably and cost of these entries is very high due to the requirement of very heavy artificial supports. The analysis includes assessment of the cause of cutter roof and step by step action taken to improve the entry condition through appropriate longwall panel entry design and roof support system. The approach for solving the problem was two-fold: 1) to apply yield pillar concept in order to reduce the effects of in-situ horizontal stress in the roof strata and 2) to find an effective way to reinforce the roof strata and to support the fractured roof and avoid caving.

Jan 1, 1990

The Barmac autogenous crushing mill is one of the most successful new comminution technologies to become available to the mining and industrial minerals industries in this decade.The Barmac autogenous crushing mill is an innovative Vertical Shaft Impactor which operates in essence like a high intensity dry ore centrifugal pump with the reduction occurring primarily as a result of high velocity rock to rock impact in a fully rock lined crushing chamber. With applications in a wide range of mining and industrial minerals operations the Barmac autogenous crushing mill presents an opportunity to enhance reduction and liberation whilst providing many cost savings and production increases in new and existing plants.This paper briefly describes the operation of the Barmac autogenous crushing mill and reviews its benefits.

Jan 1, 1990

By Deni Pageau, Deni Caron

"This paper describes the operations of the open pit and emphasizes particular aspects of Les Mines Selbaie. The open pit as well as its related services were incorporated into a complex which includes an underground mine and a concentrator. The equipment was chosen with the objective of auto-sufficiency during each phase of mining. The paper outlines the organization and the methods used in each step of mining, notably: drilling, blasting, loading, transporting and crushing. The responsibilities of the Engineering Department are also outlined from the conception of the open pit to the latest follow-up methods. A short resume of the results which have been obtained as well as suggestions for improvement are provided.Layout in Consideration of Main SiteThe A-I zone deposit is located I km from 8 zone. Open pit mining of A-I zone required the regrouping of different services to those already existing.I. The crusher was placed in an area close to the concentrator in order to minimize the length of the conveyors and to provide space for the crushed ore reserves (50000 tonnes).2. The location of the service building (warehouses, mine offices, maintenance, engineering and geology) raised a few problems. Because of the multiple services provided therein , it was impossible to fulfill all the requirements, and the garage in itself is located a fair distance from the pit. Added to this inconvenience is the fact that heavy equipment regularly travels throughout the main yard.3. The storage of explosive magazines has been changed to obtain more surface space and meet government regulations.4. A space has been provided for minor repairs in the garage used during exploration. A trailer was installed next to the garage to provide a lunch room for the employees working at the open pit."

Jan 1, 1990

By J. J. Scott

As a Rock Mechanics investigator, the author has, Over his career, attempted to use his best knowledge in developing better rock control fixtures. Based on the experience of nine years of development of friction rock stabilizers, in 1980 he decided to launch a new investigation to develop a unique roof support fixture which would fit the coal mining market. The largest single user of roof bolts in the world is the American coal mining industry, historically using up to 100 million fixtures per year. In 1989 they used approximately 82 million fixtures.

Jan 1, 1990

By R. L. Grayson, Y. J. Wang

An integrated approach to the management of underground coal mine production and cost is presented. A conceptual model for objectively analyzing an underground mine to obtain lower cost and higher productivity from operations is outlined. The model is designed to provide mine managers with a quantitative, decision-assisting methodology that can be used in formulating timely responses to fluctuations in operations. It consists of a productivity fore- cast component, routine use of current resource consumption factors, a linear programming scheduling component, a manpower loading analysis, and an inventory control component. The model is applied to an underground coal mine.

Jan 1, 1990

By Kavetsky A, Scott A

As well as breaking and moving rock, blast energy sets up a seismic wave in the ground which can cause significant damage to rock structures and buildings and disturbance to human occupants. This seismic ground vibration is potentially most damaging when its dominant frequency coincides with the resonant frequency of a structure, leading to high amplification factors between the input ground vibration and the resulting structural response. This paper outlines methods of identifying the resonant frequency of structures. It also describes a practical numerical method for the modification of blast designs to reduce the ground vibration energy in critical frequency ranges. The method is illustrated with two recent case studies.

Jan 1, 1990

By J. C. Edwards

To have the capability to predict the development of localized spontaneous heating within a porous coalbed that is subjected to forced air ventilation or in an otherwise quiescent environment in which buoyancy develops, the Bureau of Mines developed three time-dependent mathematical models, which were used to calculate the temperature increase associated with chemisorption of oxygen by the coal. In each model, spontaneous heating is driven by an Arrhenius first-order reaction between the oxygen and coal. Two models are two-dimensional, and one is one-dimensional. In the first two-dimensional model, a constant-velocity forced convection airflow is specified; and in the other, buoyant flow is allowed to develop in the absence of forced convection. The third model evaluates the airflow from Darcy's law and a specification of the pressure at the surface of a one-dimensional porous coalbed. Numerical computations demonstrated how each model could be used to predict the onset of spontaneous heating when the porous coalbed was subjected to constraints of an imposed internal heat source or a high temperature airflow. The effects of particle size and coalbed compaction upon spontaneous heating were examined with the third model.

Jan 1, 1990

By Philip L. LeHoux

In recent years, much work has been done to explain the nature of the gold-carbon adsorption mechanism. The benefits of a sound theoretical basis has the obvious application to gold adsorption and elution industrial processes. Unfortunately, the lack of a clear agreement on the mechanism has provided no clear direction towards process innovation and optimization. Jones' (1989) work has gone a long way towards clarifying the specie of gold adsorbed (and thus the chemistry required to remove it). Since the development of hot caustic and cyanide elution, the kinetics have been accelerated by the application of pressure to increase elution temperatures beyond the boiling point at atmospheric pressure. However, the traditional reagent content of 15 g/L NaOH and 5-10g/L NaCN has remained largely unchanged. This is in spite of work that has shown that the presence of cyanide is not required for the elution process to take place (Adams, 1986; Adams; 1989; Jones, 1989). Adams (1989) has also compared NaOH elution rates with and without cyanide. He found improvement with the use of cyanide and a synergistic effect with the use of both. Others have found no difference in overall extraction (Jones, 1989

Jan 1, 1990

By Sharmil Markar M

Ballarat Goldfields Limited is currently re-opening the old workings of the East Ballarat Goldfield which contain an estimated 1800 ML of groundwater. The disposal of this 'minewater' was of concern: the minewater is of moderate salinity; increased salinity levels have interfered with agriculture and water use at a number of locations downstream from Ballarat. Extensive numerical studies indicated that treated minewater could be discharged into the Ballarat Creek system for dilution by sewage effluent and by surface runoff after rainfall events. An automatic real-time salinity management system has been developed to enable the disposal of saline minewater in this fashion. A desk top computer operates the system: discharge and salinity readings are taken automatically each hour and filed away; the maximum allowable rate of discharge of treated minewater is calculated; pumps are switched on and off. The system readily enables daily, weekly and monthly data reports together with floppy disks of 'raw' data to be prepared in formats suitable for direct submission to the Victorian Environmental Protection Authority.

Jan 1, 1990

Develop methods of enhancing and measuring the high-temperature softening and melting properties of iron oxide pellets reduced under simulated blast furnace smelting conditions. Approach Add dolomite and Limestone flux and a low-cost organic binder, such as starch, carboxyl methylcellose (CMC), or waste papermill sludge, to the iron oxide concentrate to produce hematite (ferric oxide) pellets with superior high-temperature metallurgical properties. Simultaneous increases in softening temperature, gas permeability, and enhanced metallization rates are sought to improve blast furnace productivity and energy efficiency. Background In the past, bentonite, an inorganic binder, was the only additive (binder) used in the production of pellets made from iron ore concentrate. Research has shown that the reducibility of conventional (acid) pellets can be increased by the addition of flux or an organic binder. The increase in pellet reducibility results in less wustite in the center of the pellet at high temperatures, such as those obtained in the cohesive zone of the blast furnace.

Jan 1, 1990