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By R. F. Sharpe

THE Bullion mine, in the famous Cariboo district of British Columbia, is situated on the left bank of the South fork of the Quesnel river, approximately three miles below the outlet of Quesnel lake. A good road leads 63 miles northeast to the property from Williams lake, the railhead on the Pacific Great Eastern railway. The mine may also be reached over good roads from Vancouver via the Fraser canyon, Ashcroft, Clinton, and the 150-mile house, a total distance of 407 miles. In the early days of placer mining on the South fork of the Quesnel, several rich bars were found. The 'pay' on one of these at the mouth of Dancing Bill gulch was followed up the gulch by a Chinese company, who proved to be the discoverers of the present Bullion mine. This Chinese company commenced working in 1884, in what was then referred to as the China pit. Although working under very primitive conditions, it is reported that, during the ten years they operated the property, they recovered in excess of $900,000 in gold. This somewhat large recovery was due to a local concentration, the result of Dancing Bill creek having meandered down that portion of the channel and washed off the overburden. In 1894, a syndicate composed largely of the Canadian Pacific Railway directorate of that time, with J. B. Hobson as their field manager, acquired the property, as the apparent magnitude of the operation was too great for the resources of the Chinese company. Mr. Hobson, during the first ten years of his regime, developed the mine into a large-scale hydraulic operation, and during that period, from 1894 to 1905, recovered approximately $1,234,000 in gold. In 1906, the property was sold to the Guggenheim Exploration Company, who retained Mr. Hobson as Manager and embarked on an extensive programme to bring in additional water. This project was never completed, however, work being suddenly abandoned in 1907 and the mine closed down. Shortly afterwards, the property was purchased by a small operator on what is believed to have been largely borrowed capital. This venture resulted in no production, but in much litigation, which eventually reached the Privy Council in 1920.

Jan 1, 1939

By S. Z. R. Pinkney

Positron Emission Tomography (PET) is a medical technique that produces three dimensional images of the body, commonly to aid diagnosis and treatment of tumours. PET has been developed by the University of Birmingham in order to track particles in an opaque system which is known as Positron Emission Particle Tracking (PEPT). The object to be tracked is irradiated. As the radionuclide decays positrons are produced; when these collide with electrons a pair of concurrent parallel back-to-back gamma waves are emitted and detected, from which the position of the object can be calculated. Stirred media mills are used for particle size reduction. The mill is usually operated at high solids loading with grinding media and has a polyurethane or polyurethane-lined steel pot and is thus opaque. For this study grinding media has been directly irradiated and tracked using the PET camera during the grind. The stirred media mill can be divided into cells of equal volume known as voxels. The fraction of the total time the irradiated media spend in each voxel can be shown in an occupancy diagram. The mean velocity and kinetic energy of the media for each voxel are calculated and also plotted. In occupancy and kinetic energy plots colour indicates the value of the voxel, in dimensionless time and Joules respectively. The arrow in velocity plots shows direction and length of arrow indicates magnitude of the mean velocity for the voxel. From these diagrams and further data analysis a detailed understanding of the flow patterns, media behaviour and high energy areas of the mill can be developed. Variables considered were the tip speed of the impeller and density of the grinding media. It was found that the grinder has three distinct regions: above, at and below the impeller with each region having its own flow patterns and velocity and kinetic energy profiles. These are different for each variable and so are used to characterise the grind. Tip speed and density of the grinding media were shown to both affect the velocity of the media and the proportion of time spent in the each region of the grinder.

Aug 1, 2013

By T. V. Nethery

Introduction A brief account of the East Malartic fire is essential if this paper is to serve the purpose implied by its title. The fire originated in the timbers of No. 4 shaft at the 10th, or 1,570-foot, level; this was the top or collar of the underground sinking operations. At the time, sinking was in progress and the shaft bottom was 242 feet below the 12th station horizon, or 618 feet 'below the l0th level. Above the l0th level, the shaft was not in use as the surface plant was not yet completed. The shaft crews descended from surface in No. 3 vertical shaft to the l0th level, where they transferred to No. 4 shaft, a distance of 1,450 feet. Of the sixteen shaftmen mucking at the shaft bottom, four were able to reach safety. One shaftman was overcome by fumes midway between the two shafts on the l0th level, while attempting his escape. The remaining eleven men climbed as far as the 11th station and there succumbed to carbon monoxide. No. 4 shaft, inclined at 61 degrees, bad been raised and timbered from the 10th level to surface; this bad been followed by sinking operations below the l0th. Two air hoists had been set up in the footwall of the shaft, 110 feet above the 10th level, and directly behind compartments No. 2 and No. 4. The waste from the shaft bottom was hoisted in 28-cubicfoot buckets on mono rails and dumped over standard shaft sinking doors into waste chutes built into No. 1 and No. 3 compartments. The five-compartment shaft, 7 ft. 8 in. by 34 ft. 6 in. overall size, was heavily timbered. In addition to the standard shaft timbers of 8 in. by 8 in. and 8 in. by 10 in. B.C. fir, the hanging-wall and ends of the shaft were laced with 4-inch spruce lagging. This represented approximately 300 board feet of timber in placee for every foot of shaft. The cause of the fire bas never been determined, despite every effort to do so. The inquest held for those who lost their lives in the fire was an extremely thorough one, but only the location of the origin, and not the cause, was established.

Jan 1, 1950

By M. S. Badollet

Introduction Very little fundamental research has been done on asbestos fibre to cake maximum advantage of its properties and to determine in what commercial products it can best be utilized. For the research chemist who is associated with asbestos development work, a thorough study of mineralogical information on asbestos deposits would furnish reliable information on the rock formations and the mineral impurities closely associated with the asbestos. Furthermore, ?he must have an intimate knowledge of the uses of the fibre in various products so that he can visualize the importance of the fibre and the role it plays in industry. Some of the properties of asbestos fibres such as strength, composition, length, harshness or softness, and mineral associates are of considerable importance to the manufacturer because they are responsible for many production difficulties. Fibre Strength It has been known for some time chat asbestos filaments have considerable tensile strength. These strengths have been referred to merely as 'weak' to 'very strong'. Not until recently have numerical values been applied to the strengths of asbestos fibres. But today we can take a thin fibre filament and mount it between two holders and apply a gradually increasing load or pull until the fibre breaks. By measuring the cross sectional area of the filament and the amount of load applied, we can calculate the tensile strength of the fibre in terms of pounds per square inch. This type of test is slow and rather difficult, but the fundamental data obtained furnish important basic information that can be applied to mechanical processing equipment and to certain asbestos products.

Jan 1, 1948

By Raymond B. Hryciuk

Environmental auditing has evolved rapidly over the last decade — first in North America, then Europe, and most recently in Asia — into a widely practiced discipline designed to provide senior management with assurance that operations are being managed in compliance with established governmental standards, internal company policies, and good industry practices. This paper first examines the evolution of environmental auditing, focusing in particular on three interlocking driving forces: company initiatives, collaborative industry initiatives, and government initiatives. Characteristics of effective audit programs, those that have emerged among the leaders, are discussed, including: objectives, scope, coverage, approach, staffing, and organizational considerations. The author then addresses important future trends and developments for environmental audit program design, content, and coverage.

Jan 1, 1996

By A. F. Robertson

FOR several years, the rock-burst question has been given serious consideration by the operating staff at Wright-Hargreaves mine and, as a result of observations and experiences, several different methods of mining have been developed which are now in use in various parts of the mine. These are described in the following pages. It should be emphasized, how-ever, that these methods, and the views expressed in this paper, are based solely on conditions at Wright-Hargreaves mine. Such conditions may or may not be similar to those obtaining in other mines in the Kirkland Lake area, where ore occurrences, veins, wall-rock, faulting, intrusives, etc., may be entirely different. Size and shape of ore-bodies, composition of the ore-bodies and their surrounding rocks, locations of intrusives and sedimentary rocks, and direction, dip, and strength of faults, all introduce problems that are peculiar to each individual mine. Ground failure' in coal and metal mines is not at all unusual. A variety of systems of mining have been developed to delay movement of large or small blocks of ground, or, in some instances, to take advantage of the fact that ground movement, due to mining operations, is unavoidable. Ground failure may be either slow collapse or it may take place with explosive violence. It is principally with the latter condition that we are concerned in the mines of the Kirkland Lake district.

Jan 1, 1939

By J. Chretien

The ability to continuously monitor the air quality within a mine has become instrumental in becoming a low cost producer. The many considerations involved in monitoring air quality include sensor type, hardware placement, as well as data storage medium. BESTECH has had the opportunity to gain insight into these air quality monitoring considerations through deployments of NRG1-ECOTM, a minewide energy consumption optimization system. This paper explores the particular challenges overcome through these installations, and provides a set of guidelines for mines that want to maximize data capture while minimizing costs. It provides a view of additional benefits of air quality monitoring, such as ventilation control, reporting and trending.

Aug 1, 2013

By R. A. Nemchek

Over the years, concentrator plant design has evolved from a large number of small grinding mills to a small number of large mills. In many cases, all of the tonnage runs through a single mill (typically a large SAG mill), so that the plant?s performance hinges on the productivity of this one machine. Industry specifications attempt to address the critical nature of today?s grinding mills in a manner that is often overly complex, neglects economics, and is not clearly focused on the end user?s goals. This paper surveys current industry practices, and proposes an improved approach to standards writing recognizing that product design, procurement, manufacturing, and quality are all inter-related in contributing to a project?s success. The lessons learned here can be extended to specifications for all types of machinery.

Jan 1, 2012

By Christopher R. Lattanzi

"Discounted cash flow analysis provides a means of relating the magnitude of expected future cash profits to the magnitude of the initial cash investment required to purchase an asset or to develop it for commercial production. The objectives of discounted cash flow analysis are to determine:.. The net present value of a stream of expected future cash revenues and expenditures... The rate of return which the expected future cash flows will yield on a given level of initial cash investment.In the case of mineral properties, discounted cash flow analysis is generally accepted as the preferred method of valuation, whenever sufficient data are available to permit its reasoned application. Sufficient data are required to support estimation of all of the individual elements of cash revenue and cash expenditure which will be associated with the development and operation of the property, up to the end of its estimated life. It is the accuracy of these input estimates which determines the validity of the resulting determinations of profitability and rate of return on invested capital.In undertaking any discounted cash flow analysis, it is important to recognize certain fundamental attributes of the mining industty:.. The basis of any mineral development is the existence of an ore reserve... Costs are determined by the number of tonnes mined and processed, while revenues are determined by the number of pounds or ounces of metal produced. The two are related by the recovered grade of the ore... Profit is typically more sensitive to changes in revenue than it is to changes in cost... Commodity price is a principal determinant of revenue, but it is also the factor with which is associated the greatest level of financial risk.In the end, of all of the factors which must be considered in the discounted cash flow valuation of a mineral property, the most significant are the reliability of the reserve estimate, particularly with respect to recovered grade, the price at which the product is to be sold, and the risk of not maintaining the projected level of price."

Jan 1, 2003