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By Edward F. Divers

The Bureau of Mines recently tested a sideboard device that is designed to act as an extension of conventional brattice, thus improving face ventilation of developing room-and-pillar-type coal mining. In these laboratory tests, an 8-foot-long rigid sideboard was mounted vertically along the left fender of a full-scale-model ripper-type continuous mining machine, rising to the mine roof to provide an air seal. It extended from the auger support frame pivot point outby along the fender. A novel water spray manifold was used to form an air seal between the sideboard and brattice. Tests showed improvement in face ventilation with the prototype device, and also demonstrated that water sprays can form an effective air seal over a fairly wide pressure range. Based on this preliminary study, subsequent improvements may make the sideboard concept much more effective, thus affording a simple, inexpensive technique to improve the effectiveness of face ventilation.

Jan 1, 1979

By Charles B. Dugger

Sacrificial linings for grinding mills have been a necessary state of the art of mineral dressing since the inception of comminution. Long recognized as the final link in energy transmission from power line to ore, mill liners as a scientific endeavor have not expanded as rapidly as other branches of mineral dressing engineering. Several reasons for this technological lag are apparent. Typically in the past, labor intensive foundries were freely located geographically, at a time when transportation charges made up a significant portion of the casting cost. Alloying agents had not gained their current level of sophistication and were relatively inexpensive in the quantities required. Precise foundry controls were not economically justified, or totally understood. Coincidental to these elements, liner consumption per unit processed did not categorically contribute as a major cost item to the mill operator. Grinding equipment was small, and many times lining life exceeded that of the promoter. These unique conditions no longer exist. Ore dressing equipment has grown to meet modern mining demands. Larger processing facilities, utilizing fewer pieces of equipment, have replaced operations of the past. Emphasis today and tomorrow is on larger and larger equipment, with an eye on lower and lower unit processing costs.

Jan 1, 1979

By R. G. Bradbury

The paper uses two hypothetical, but typical, situations to show that hydraulic rock drilling equipment has very significant economic advantages over pneumatic equipment both in drifting applications (even in the situation where advantage is not taken of the high productive capacity of the hydraulic drill) and production drilling applications. Other factors, including the non-economic advantages and the disadvantages of hydraulic drilling, are discussed. The paper concludes with a brief analysis of why the Canadian mining industry has been slow to take advantage of this apparent broadly advantageous advance in rock drilling technology.

Jan 1, 1979

By Ted M. Noskiewicz, James A. Ramsay

INTRODUCTION During the various stages of an underground project from inception through design and construction, probably the single factor of most interest and concern is the nature of the ground. The ground conditions more than any other item govern costs and feasibility; and although the methods available for assessing the ground have become increasingly reliable during the past thirty years, it is still very difficult in many cases to predict the behaviour of soil and rock during and after excavation. To help in this ground evaluation process, we have frequently supplemented the boring program with one or more large diameter inspection holes; and during the past eighteen years, seventeen of these holes have been constructed on tunnel projects which we have designed. There are references in the literature to similar inspection holes (1); however, as far as we are aware, no detailed description of them has been published. The behaviour of soil or rock during and after excavation and the effect of ground water on tunneling operations are of vital interest to tunnel designers and contractors. A comprehensive geotechnical investigation is therefore among the early and most important tasks carried out on a tunnel project and the backbone of every geotechnical investigation is the boring program. A series of borings, typically 50 to 100 mm (21 to 4 in) diameter, are drilled from which soil samples or rock core are recovered and the ground water observed.

Jan 1, 1979

By T. H. Jeffers

To help maintain an adequate supply of minerals to meet national, economic, and strategic needs, the Bureau of Mines investigated the feasibility of extracting copper from coarse native copper ore with ammoniacal ammonium carbonate solution by a simulated in situ leaching procedure. A 5.9-metric-ton (6.5-ton) sample of minus 30.5-centimeter (12-inch) conglomerate-type ore analyzing 1.96 percent copper was leached in a column for 556 days with a solu-tion that contained, in grams per liter, 2.2 NBs and 1.9 CO[3=]. The copper extraction was 71.4 percent, and reagent consumptions were, in kilograms per metric ton of ore, 1.1 NBs and 0.85 CO[3=] (in pounds per ton of ore, 2.2 NH3 and 1.7 CO[3=]). The pregnant leach solutions contained about 1.4 grams per liter copper, which was readily extracted from these low-tenor liquors with a 1:19 mixture of an organic extractant and kerosine. Copper was stripped from the loaded organic with depleted electrolyte containing 150 grams per liter H2S04, and the copper was recovered by electrowinning with antimonial lead anodes. Conditions also were established for minimal lead transfer to the cathode copper.

Jan 1, 1979

By H. M. Friede

A short survey is given of the Iron Age smelting sites and smelting furnaces that have been found in South Africa. An attempt is made to classify South African smelting furnaces by the inclusion of functional characteristics such as the numbers and positions of tuyeres. An affinity is suggested between the Venda (eastern Transvaal) type of furnace and an East African type. The principles of the smelting process in South African Iron Age furnaces and the characteristics of the smelting products are discussed. Results of metallographic and chemical analyses of 19 iron specimens found at South African sites are given and compared with those from sites in Zimbabwe-Rhodesia, Mocambique, and Nigeria. The carburization and steeling of iron during primitive smelting and forging are discussed.

Jan 1, 1979

By R. J. Lee

Asbestos analysis is conceptually simple. The objective, in most environmental analyses, is to determine the number of asbestos fibers per unit area or volume in a sample. The sample may be a consumer product, an ambient air sample, or a water sample. This determination is complicated by several factors including sample collection and preparation, counting techniques, and the operational definition of asbestos in use. Three different definitions have been used in the study of environmental samples; these are summarized in Table 1. [ ]

Jan 1, 1979

By W. D. Bonisteel

In 1976, Rio Algom Limited began the expansion of uranium production facilities at Elliot Lake. Quirke Mine was the only property in operation at the time, and plans were made to expand its milling capacity from 4,500 to 7,000 tons of ore per day. Following this expansion, other properties in the area will be reactivated to fulfill long-term contracts for uranium. As part of the expansion program, it was decided that in view of the escalating cost and impending shortage of energy, heat reclaim and conservation would be employed wherever practicable. In general terms, heat reclaim applications fall into three main classifications: ventilation, utility and process. Two of the ventilation applications and one process application will be described in some detail. Several other systems will be presented briefly as a matter of general interest. Some future possibilities will also be mentioned, together with their potential for economical heat recovery.

Jan 1, 1979

By G. Camposano, J. Aponte, B. A. Ferguson

The paper covers mining operations and preparation of the ore prior to metallurgical treatment in the Process Plant. Mining operations are primarily concerned with the delivery to Ore Preparation of a balanced ore feed within fairly rigid specifications as to both ore type and chemical analysis. The mining method, systems of geological and engineering control, and the equipment employed are therefore reviewed in this context. In Part One of the paper the physical and geological characteristics of the orebodies, including the varied nature of the ore itself, are first described. Orebody evaluation, the calculation and classification of ore reserves, mining planning and forecasting to ensure continuity of production are covered, and the particular problems presented by sampling, the erratic distribution of ore values and the variation in the density of the ores are also mentioned. Mine design and ore excavation practice are described, together with the way in which they have evolved with recent developments in modern mining equipment. In Part Two of the paper, a detailed description of the Ore Preparation plant is given, centred around the concept of rubbling as a means of separation of the barren hard boulders from soft lateritic ore. Ore blending and ore reclamation operations are explained followed by a detailed description of the drying and crushing plant. The importance of the control of moisture content and ore sizing in the feed to the metallurgical plant is emphasized.

Jan 1, 1979

By Ralph W. Crosser

The emergence of residuals management as a planning and management tool in the mineral industry has been recently accelerated by the proliferation of environmental regulation and its associated costs. Residuals management practices allow for the early determination and integration of both production and environmental goals in the development of management strategies to arrive at the most cost effective, environ- mentally sound solution. The term residuals management was in actuality derived from the substitution of the word residual for the term ?pollutant? or ?waste?. A residual can be defined as a non-product output having no value in existing markets or a value less than the cost of marketing it. The values of the residual can be determined by time, technology, government policy, market conditions, etc. Residuals basically fit into two classes -- materials which are composed of liquid, gaseous or solids; and, energy, which mainly consists of heat and noise. These residuals are interrelated and can be modified by adding materials and/ or energy, which also may become a residual; thus, lending themselves to alternate disposal schemes to control the adverse effects.

Jan 1, 1979

By David C. Grant, Erich W. Tiepel

In situ mining is a process for recovering uranium from relatively small or low grade ore bodies. The process involves passing a lixiviant and oxidant, typically NH4HC03 and H202, through a uraniumcontaining ore body. As the solution progresses through the ore body, the uranium is oxidized from the plus four to the soluble plus six state. The bicarbonate complexed uranium laden solution is removed from the ore body and the uranium recovered in an above-ground processing plant. During the leach process lixiviant cations may be sorbed on the ore host, if the host contains exchangeable clay minerals. This report examines the implications of this clay interaction on ground-water quality, the various available in situ mining restoration methods, laboratory procedures for simulation and development of those methods, and the results of using the restoration methods in the field. Various restoration methods, including ground-water sweeping, clean water recycle, and chemical restoration are presented and discussed. The use of ore characterization, agitation leach tests, and column tests to study cation sorption and desorption, and thus, to identify and evaluate restoration methods is discussed. Ore characteristics identify the clay type and clay content, which allows the estimation of the magnitude of the cation sorption by that ore. The chemical effects of clay exchange and of chemical restoration can be examined using agitation leach experiments and packed ore column tests which also provide information on the physical effects. The agitation leach test is a relatively rapid means of determining the sorption and desorption characteristics of an ore. Unlike agitation leach tests, column tests can be used to assess the influence of solutions on permeability, on precipitation problems, and on other chemical changes. The effectiveness of using restoration methods, which were developed and tested in the laboratory, are examined by presenting field restoration data from several mining sites.

Jan 1, 1979

By D. D. Howat, J. van der Colf

Slags of the system CaO-MgO-AI2O3-TiO2-SiO2at had been reduced in graphite crucibles for selected time Intervals were fully re-oxidized so that an assessment could be made of the rate and extent to which the titanium oxide had been reduced. The derived kinetic parameters were studied as functions of slag composition and temperature. The extent of reduction after selected Intervals of treatment could be correlated with the physical behaviour of the melt (in terms of viscosity and electrical resistivity).

Jan 1, 1979

By Gilmore R. Tostengard

The advent of inexpensive computers has opened vast opportunities for improved planning and control of capital projects. The mining and mineral processing industries have welcomed the opportunity, and new and improved quantitative management techniques have abounded. This chapter will discuss commonly used computer applications for economic justification of the project, preparation of the cost estimate, planning the work schedule, monitoring work progress, and control of costs and productivity. Finally, there is a review of the degree to which the industry uses these applications. Our experience suggests that while we in the industry have been quick to adopt the new techniques, the quality of our input data has not always kept pace. During the next decade, our push should be toward improving the quality of the basic data and assumptions so that we can fully benefit from the sophisticated techniques. The GIGO (garbage in, garbage out) principle is a wellworn cliche, but it is especially valid here. One of the keys to getting good input is commitment. Unless the managers who are to use or benefit from the system are committed to it, the effort will fail. They must be com- mitted to the underlying principles of planning and control sufficiently to expend their time and resources on them; planning should be especially given emphasis. They can't be too busy to plan.

Jan 1, 1979

By F. F. Aplan

INTRODUCTION The production of coal is a major part of the mining industry. In recent years the production of clean coal has exceeded 600 million tons per year and is reported to have reached 660 million tons in 1977. Some data on the magnitude and utilization for the year 1975 is given in Table I. In that year 648 million tons of soft coal were produced and of this 267 million tons or 41% approximately was produced by mechanical cleaning. Of the 374 million tons of raw coal sent to the preparation plant, 28.6% or 107 million tons was discarded as refuse. In the same year approximately 6 million tons of anthracite were produced and nearly all of this was cleaned. Table I also gives coal utilization statistics for 1975. Excluding the approximately 20% that goes to the coke ovens or to export, the vast bulk of our production is used for steam power generation and a lesser amount for captive production of industrial power and process steam. While much of the nation's coal (e.g. strip mined western, sub-bituminous coal) may be removed from the ground in relatively pure form by modest selective mining techniques, other coal requires preparation in order to remove ash and sulfur constituents and produce an acceptable steam or coking coal. Preparation is often a valuable adjunct to mining in that rather non-selective, low cost, bulk mining techniques may be used underground while the preparation plant is used to reject refuse at low cost above ground. The principal reason for the use of coal preparation is to convert raw coal into an acceptable commercial product by removing the high ash and high sulfur refuse material.

Jan 1, 1979

By R. D. Kelsey

The theory, definition and practical application of cutoff grades have evolved over a long period. This evolution is reflected in the continuing flow of papers on this and other related matters though the rate has varied as new ideas and theories have become understood and applied in practice. Papers by Lane(l) in 1964 and Taylor(-2)- in 1972 provided landmarks in the understanding and general communication of cutoff grade theory and its application. The reasons for the continuing interest in cutoff grades are obvious. Too high a cutoff can reduce the mineral recovered and possibly the life of a deposit. Too low a cutoff would reduce the average grade (and hence profit) below acceptable levels. This paper provides a brief overview of existing cutoff grade theory and some particular aspects of its application.

Jan 1, 1979

By P. R. Cook

Thunder Bay Terminals' plant, now in operation, cost about 70 million dollars and was completed on time and under budget. The paper is the project manager's account of this accomplishment. From site selection through feasibility, engineering and construction to realization, he emphasizes the necessary philosophies for the control of time and money. The computer as a tool is discussed, as well as techniques for procurement.

Jan 1, 1979

By Ernest L. Bradley

A positive pressure ventilation system, augmented by a dewatering well curtain and underground longhole drilling, provides effective ventilation and radon control at EXXON Minerals Company's Highland Underground Mine in the Southern Powder River Basin of Wyoming. Testing different types of bulkheads, sealants, and bleeder systems has led to improvements in the basic ventilation system. Continued testing of new or different materials and equipment is expected to lead to further improvement in the ventilation program. Effective training of both miners and supervisors is essential to maintaining and improving ventilation techniques. This paper addresses the ongoing ventilation program and experience to date at the Highland Uranium Mine.

Jan 1, 1979

By Welland L. Ott, Hans J. Rumland

The Falconbridge Dominicana laboratory receives samples from all parts of the operation. Ore, metal and oil samples are taken by operating departments, gas and water samples by the laboratory staff. Physical sample preparation is essentially standard and produces comminuted samples for wet-chemical analysis and X-ray fluorescence analysis (XRF). T he main operating sections of the laboratory are described indicating in each case the type of instrumentation and method used, sample types analysed and comments on problems experienced. Emphasis is given to the sample preparation and X-ray sections especially with regard to the difficulties caused by our heterogenous ore material, calibration of the instrument and operational malfunctions. General problems related to our remote location and the tropical climate are discussed. Limited statistics on instrument availability, and stability, accuracy, precision, etc., are given.

Jan 1, 1979

By Edward S. Plotkin

The tunneling construction industry faces a new challenge in endeavoring to comply with the multitude of regulations and standards of the Occupational Safety and Health Administration and to work following accepted and experienced tunneling practices. Tunnel inspections appear to be gaining in priority. The national OSHA inspection activities reported for the year 1976 in the construction industry are as follows: 989 Inspections 45 As result of Accidents 186 As result of Complaints 605 General 153 Follow Up 34% Were found to be in compliance 714 Citations were Issued 1,825 Violations were found (201 of which were serious; 1573 were non-serious; 51 were imminent danger. There were no recorded failures to abate a violation in our industry.) The five general priorities by which a company would be scheduled for an inspection in descending order are: imminent danger situations, reports of fatal accidents or catastrophies, inspections in response to valid employee C( taints, inspections of work places covered by National Emphasis Program NEP, (OSHA's NEP has been designed to impact on any industry having a very high injury or illness rate) and finally random inspections of work places covered by OSHA. The following criteria in selecting companies for random inspections is used by OSHA.

Jan 1, 1979

By Keiichi Fujita, Katsumoto Ueda, Hiroshi Nakauchi, Naohiko Okumura

INTRODUCTION This paper presents (1) modified slipform system which was employed for simultaneous concrete placement for permanent lining and Instruction of a partition wall in the execution of a ventilation shaft 620m deep, and (2) current shaft sinking techniques which have been applicable and efficient for the subsurface conditions in Japan. MODIFIED SLIPFORM SYSTEM FOR PERMANENT LINING OF VERTICAL SHAFT General Information This paragraph deals with rapid construction by using modified slipform system for the permanent concrete lining and a partition wall of ventilation shaft, which has inside diameter of 620m and depth of 620m, of Enasan Highway Tunnel. The general feature of the shaft is illustrated in Fig. 1 and standard section of the shaft is illustrated in Fig. 2. The geological condition surrounding the shaft is mainly of ryolite and surface is of talus, but as a whole, they are rather weak and weathered rocks with faults, fissures and clay seams. 220mm borehole for the geological investigation was used as a drainage hole, predicting the amount of water inflow into the shaft to be 10t/min. The shaft was executed mainly by means of the conventional short step sinking method of 1.2m lift, employing temporary headframe and hoists. For each lift, 40 to 50cm thick temporary concrete lining was used. About 28,600m3 of rocks were excavated and

Jan 1, 1979