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By J. W. M. Porritt, M. P. Brameld, R. H. McCorkell

"Soil-gas Rn was measured by two types of alpha-particle-track detectors, by emanometry and by counting alpha-activity on Rn-decay-product collectors. Soil samples were analyzed for V by fluorimetric and fission-track methods, their Rn-emanation by decay-product collectors and their total alpha activities with track detectors. The same uranium anomalies were revealed by each method. Fission-track analysis of leaves for V showed only random variations with sampling site, and the Rn emanation of trees and leaves removed from them was barely detectable . The agreement among the other methods is significant, total alpha and collector methods are simple, rapid and useful, and a combination of methods at a site would reveal disequilibrium in the U-decay series if present. Track-Rn measurements are highly reproducible and insensitive to apparatus design and their sensitivity is not enhanced by covering the detectors with thin foil or placing them in large containers.IntroductionIn the past two years , a number of methods of geochemical exploration for uranium have been tested by the authors over the known copper-uranium occurrence at South March, Ontario. This was done partly to compare methods and partly to develop and test new ones. The South march deposit has been described a number of times by others(1,2,3,4). The methods included in this study were the following.Emanometry, Radon in soil gas is measured by pumping the gas into the cell of a scintillation counter or emanometer(5,6). Alpha particles from radon (222Rn) and its decay products (218Po and 214Po) produce scintillations of light in the silver-activated zinc sunphide (ZnS(Ag) covering the walls of the cell. These are counted by a photomultiplier tube and scaler, the count ra sulphide (ZnS(Ag) covering the walls of the cell. These are counted by a photomultiplier tube and scaler, the count rate being proportional to the concentration of radon in the soil gas."

Jan 1, 1981

By V. C. Wittchen, T. R. Yu, J. E. Croxall

"The consolidated rockfill at Kidd Creek Mines is a weakly cemented, minus 15 cm aggregate which posed problems for conventional drill/blast drifting methods. Consequently, lateral access to mineable ore adjacent to backfilled areas was gained by drifting around the fill in shattered rock.In mid-1987, Kidd Creek Mines began to investigate means of mechanically excavating drifts in backfill . The results of this investigation led to a trial program using a Dosco MK-2A Roadheader to excavate the required drifts in backfill.The roadheader was tested at Kidd Creek Mines from July to November 1988, in 28-735 X /C to be used as the top access for drilling and blasting 32-74/ ST. During this period, the roadheader excavated 54 m of a 4.3 m by 3. 7 m arched drift in backfill. Cutting rates over the period averaged 0.8 m/cutting hour as projected with a daily high of 2.0 m/cutting hour.Wood-lagged 2-piece steel arches on 1.2 m centres were chosen as ground support for the trial. Shotcrete will be tested in a roadheader drive for its potential to improve productivity by replacing the steel arches.The trial program included evaluations of point-attack picks, two sizes of cutter motor, 20 MPa (3000 psi) water-assisted cutting, cuttings-removal systems, and environmental control devices."

Jan 1, 1990

By Jorge Lema Patino

"The purpose of this paper is to determine the best techno-economic alternative for the treatment of tin ores, when comparing the various mining and metallurgical methods of preconcentration, concentration, volatilization (fuming) and up to the final stage of selling to the smelter. The study of the influence of the different parameters of cost, recovery and quoted prices has motivated the paper, which aims at determining the best process of ore treatment in terms of its techno-economic feasibility.Method of WorkOn the basis of head grades of 0.5, 0.75 and 1.0% tin, the following alternative methods of treatment are possible:1. Mining-Concentration-Smelting.2. Mining-Preconcentration-Fuming-Smelting.3. Mining-Concentration-Separation, with direct smelting and fuming/smelting of the two fractions produced.The calculations were carried out on the basis of existing information and publications concerning the various experimental recoveries in the operating mills of COMIBOL. In the case of concentrates containing less than 10% or more than 40% tin, extrapolation was required.The final grade of the tin concentrates and the gross weight of the concentrate were calculated on the basis of the estimated recovery curves. The costs of the preconcentration and the concentration stage s were determined per gross metric ton of material treated.The calculation of the cost of the smelting stage is similar for all the alternatives, the royalties and smelting charge varying with the grade of the final concentrate. In the fuming stage, a uniform recovery of 90% was taken in all cases so as to obtain a final concentrate grade of 65% tin, regardless of the head grade of the feed material.For the separation stage, the following considerations apply:a) Separation can be carried out by gravity separation or flotation methods.b) The cost of separation varies depending on the system used.c) The distribution of tin in the two fractions is 100% at this stage. In other words, there is no loss of tin during separation."

Jan 1, 1982

By Norman Lecuyer, Jacque Nantel

"The Chadbourne Project, located within the limits of the town of Noranda, Quebec, will make use of backfill materials to fill the voids left by the mining of stopes and pillars. A series of tests were conducted on different mixtures of slag and pyrrhotite tailings materials to evaluate their properties. The tests are described and some pertinent results are given in the paper.IntroductionThe Chadbourne Project is located in the centre of the Town of Noranda, Quebec, with houses as close as 120 m from the blasting operations. The ore is mined using the vertical crater retreat method. The voids left by mining activities will be filled. A program of pillar recovery will follow.Considering the proximity of houses and the need to recover pillars, the backfill program must be carefully laid out. No subsidence can be tolerated on surface.With these objectives in mind, a test program was undertaken by Nantar Engineering Limited and Queen's University to evaluate the possible ba ckfilling alternatives available to Chadbourne. One of the possibilities retained was the use of a backfill composed of broken slag material from the Horne Smelter and pyrrhotite tailings deposited on the Horne's pond a number of years previously.The back fill used at the Horne Mine until the mine closed in 1975 was composed of a mixture of 97% granulated slag and 3% pyrrhotite tailings. The tests leading to its use underground at the Horne Mine were described by Patton in 1952. The structural properties of the Horne backfill were ""intuitively"" known; it was agreed by all at the Horne Mine that the backfill was behaving remarkably well. Some were labeling it ""the best backfilling material in the world"". Its strength was said to be that of a weak concrete. All of the preceding indicate that the Horne backfill had never had its structural and other properties determined in the laboratory."

Jan 1, 1983

By Robert B. Parsons

"There is a widespread concern that certain of Finance Minister Michael Wilson's Tax Reform proposals will likely lead to a significant decline in flow through funding after 1988. This does not bode well for the junior exploration sector, which relies heavily on flow-through to finance exploration programs. The exploration industry is actively pursuing various solutions to the problems posed by Tax Reform, in order to ensure that flow-through has a future.IntroductionWhile the proposals contained in Finance Minister Michael Wilson's Tax Reform White Paper may not be as far-reaching as some people had expected, nevertheless the combination of the existing tax rules and proposed new rules offers sufficient complexity to keep pencils sharpened for many months. After having had an opportunity to study Tax Reform since June 18, 1987, the sharpened pencils are suggesting that the White Paper is not without its shortcomings and pitfalls. Insofar as the mineral exploration industry is affected, there is widespread concern that adoption of certain Tax Reform proposals could spell near disaster for mineral exploration in Canada. More specifically, there seems to be a consensus among the industry, as well as some federal and provincial government officials, that the announced phase-out of the ""mining exploration depletion allowance"" (MEDA) would reduce the appeal of flow-through shares to the point where only a fraction of exploration funding would be financed in the future by flow-through."

Jan 1, 1987

By John R. Sullivan, Real Daigneault, Mathieu Piché, Jayanta Guha, Gilles Bouchard

"RESUMELa stratigraphie du camp minier de Matagami se résume a la présence de deux groupes volcaniques: le Groupe du Lac Watson et le Groupe de Wabassee qui le surmonte. Les gisements de sulfures massifs volcanogènes sont situés au sommet du Groupe du Lac Watson. Ces roches sont déformées par l'anticlinal de Galinée dont l'axe, orienté E-W, plonge vers l'ouest. Le cœur de cette structure est occupé par le Complexe de la Rivière Bell.Les roches volcaniques du flanc sud de l'anticlinal sont peu déformées et pendent à 45° vers le sud. Les gites qui s'y trouvent présentent la morphologie typique des gisements de sulfures massifs volcanogènes. Ceux-ci se situent le long d'un horizon repère cherteux et sulfure, appelé ""Tuffite Clef', et leurs cheminées d'altération rejoignent, en profondeur, une zone d'altération stratiforme d'étendue régionale.Les roches du flanc nord ont été transposées tectoniquement en écailles chevauchantes, de dimension kilométrique, a l'intérieur d'un couloir de failles anastomosées d'orientation est-ouest. A l'intérieur: le ce couloir, les gites de sulfures sont déformes et sépares de leur héminée d'altération sous-jacente par des failles.Les gites de sulfures situes sur les deux flancs de l'anticlinal de 'Galinée se seraient mis en place dans un mime environnement volcanique. Leur position stratigraphique est identique puisqu' ils se 'rouvent au sommet de la rhyolite porphyrique du Groupe du Lac Watson. lis se seraient constitués au cours d'une pose volcanique recédant 1'éruption du basalte du Groupe de Wabassee. Le Complexe de la Rivière Bell est perçu comme la source de chaleur responsable de la circulation des fluides hydrothermaux qui sont à ""origine des gisements de sulfures massifs volcanogènes."

Jan 1, 1990

By Robert B. Parsons

"Although the April 19, 1983 federal budget appears to put greater emphasis on new or expanded government spending programs in an effort to get Canadians working again, the budget proposals contain a light sprinkling of tax changes which could be of some direct benefit to the mining industry.This month, Tax Notes examines some of the more important of these changes.IntroductionSome sectors of Canada's mining industry could benefit from the proposed income tax changes announced by Finance Minister Lalonde in delivering his budget address to the House of Commons on April 19, 1983. Improved depletion allowance rules, expanded investment tax credits, better use of business losses, and inflation proofing of personal capital gains on Canadian common shares are all part of the measures included in Mr. Lalonde's first budget to try to reinvigorate the battered Canadian economy.Improved DepletionUnder the Income Tax Regulations, a taxpayer who incurs Canadian exploration expense (and certain other eligible expenses) is permitted to deduct not only the full amount of the Canadian exploration expense (""CEE""), but also an additional allowance (the so-called earned depletion allowance) equal to one-third of the CEE. Thus, a taxpayer in certain circumstances can claim a deduction of $1.33 for each $1.00 of eligible expenditure, including CEE.Although CEE can be deducted from any source of the taxpayer's income (for example, from investment income, salary income, and so on), prior to budget date the earned depletion allowance was deductible only from the taxpayer's resource profits. This restriction on the deductibility of the earned depletion allowance substantially reduced the attraction of the allowance: few individual investors or investment companies, for example, have the required stream of resource profits, at least when the CEE or other eligible expenditure is made."

Jan 1, 1983

By Robert B. Wickham

"American Barrick has always balanced its aggressive operating approach with a conservative financial strategy. In fact, what enables their mining team to pursue such aggressive plans with confidence is the conservative financial strategy adhered to by the company. These policies are built on a prudent mix of gold linked financings, equity and gold price hedging.This paper outlines these policies and focusses in particular on American Barrick's gold price hedging program.IntroductionThe company's balance sheet at the end of 1990 clearly shows the wisdom of its conservative policies. Total assets have grown to over US$1 billion; cash has grown to US$312 million and shareholders' equity to US$645 million. All amounts included in this paper are quoted in U.S. dollars. Increased gold production and an effective gold price hedging program also combined to produce record income from operations, earnings and cash flow in 1990.The first half of 1991 is also indicative of the benefits of the company's conservative financial policies. Increasing production, together with its comprehensive gold hedging program, has generated increased earnings, even in a period of falling gold prices.All year-over-year numbers for the first six months are up. Gold production was 36% higher; earnings of $40.2 million $ 0.30 per share - were 46% higher than 1990.Barricks revenue continued to increase despite gold prices remaining unchanged during 1990. Barrick's hedging policy protects the company from falling gold prices on the basis that the upside looks after itself. Their hedging program - including various goldlinked fmancings - enabled Barrick to realize an average price of $437 per ounce of gold sold in 1990, compared with the Comex average gold price for the year of $384 per ounce."

Jan 1, 1991

Red Chris Project Project Status ? Tahltan, Iskut First Nations MOU ? Bankable Feasibility Study ? BC Environmental Assessment Certificate ? CEAA (Federal Environmental) ? EPCM contracts LOI?s ? US$110 million Project Debt Financing(credit approval pending) ? 1st5 years concentrate production sold ? 99,150 m of drilling in 371 holes First Nations Participation Agreement ?Advanced stage negotiations

May 1, 2006

By Bo R. Arvidson

"New permanent magnetic alloys have recently opened up possibilities for development of unique mineral separators. These are now making several new applications feasible. In many cases where conventional electromagnetic-induced roll separators have traditionally been used, the new permanent magnetic roll separators may reduce both over-all capital costs and operation costs.The development of the next generation of extremely powerful permanent magnets, i.e. neodymium-iron alloys, is progressing rapidly and will affect the roll separator as well as another type of magnetic separator. Permanent Magnet Roll SeparatorDesign and FeaturesDiscs of permanent magnets interleaved with soft iron discs constitute the basic magnetic roll design (Fig. I). By enveloping the magnetic roll with a thin abrasive resistant belt (Fig. 2), even highly magnetic particles are removed.The first prototype roll utilizing the new magnets was shown to have approximately equal strength as induced magnetic roll (IMR) separators. Since the initial test roll, the new separator, called the PERMROLL® , has been made twice as strong with regard to magnetic force, that is, the magnetic flux density is determined to exceed 1.7 tesla (17 kilogauss), while the magnetic field gradient is more than twice the gradient than can be practically achieved with IMR."

Jan 1, 1985

By D. M. Ward, J. H. Ahrens

"The Fond-du-Lac uranium deposit was delineated primarily by percussion drilling and a small program of diamond drilling. Drillcore samples from three diamond drill holes as well as digitized gamma logs from percussion and diamond drill holes were utilized to define and implement an algorithm for the conversion of gamma-log data to equivalent-grade data. The procedures and detailed analysis for the provision of assay data for uranium reserve estimation are documented.IntroductionThe Fond-du-Lac uranium deposit is on the south shore of Lake Athabasca, approximately 2 km southeast o f Fond-du-Lac , northern Saskatchewan. It is on the northern rim o f the Athabasca sandstone basin.A train of mineralized glacial erratics was discovered in 1967 by Farnok, Limited by means of a helicopter-borne radiometric survey. In 1969, a program of diamond drilling by Famok was successful in locating in-situ mineralization in the Athabasca sandstone at the apex of the mineralized boulder train. Since 1974, exploration and development work have been performed under a joint-venture agreement between Eldorado Nuclear Limited and Famok Limited, with Eldorado acting as operator.From the discovery drill hole to the development of the gamma-log to equivalent-grade con version algorithm, the deposit had been tested by a total of 222 drill holes, 210 of which were percussion holes and 12 of which were diamond drill holes. The holes are generally vertical and collared at 10-metre centres on fences spaced 20 metres apart. The deposit is approximately 390 metres long, 10 to 40 metres wide and up to 45 metres deep, and is generally confined to the Athabasca sandstone. Uranium occurs as pitchblende, coffinite and uraniferou s goethite."

Jan 1, 1983

By Philip M. J. Gray

"The real cost of conversion from ore to semi-fabricated non-ferrous metals has been increasing for many years. Consumer resistance and improved knowledge and techniques now available justify investment in revolutionary as well as evolutionary methods of extraction. Metallurgical factors in current practice which preordain high production costs are identified as: smelters' demand for clean minerals, use of processes with low intensity of working per unit of reactor volume, use of low-velocity reactions, use of long reactor retention times relative to the speed of reactions, dilution of values in solution and commitment to electric power as a source of energy.Six new types of flowsheet are proposed for processing from ore to metal, composed of steps which are economic to construct and maintain and making maximum direct use of fossil fuel and the energy content of minerals. The basic knowledge and technology for developing these flowsheets exists. It is very tentatively suggested that these routes might reduce the capital and production cost for conversion of ore to metal by 30-50%."

Jan 1, 1980

By P. Mottahed, E. K. S. Passaris, J. Q. Ran

"The jointed roof of underground mine openings in stratified rock can be analyzed in terms of a voussoir beam. Because of the essential indeterminacy of the structure, previous attempts of theoretically solving the equilibrium equation have been unsuccessful. Numericalanalysisby the finite element method taking the geometrical and joint non-linearity into consideration combined with the experimental method has been adopted to study the performance isopara of the voussoir beam. Deformation and failure mechanism is analyzed in relation to the failure modes. Equations are proposed to estimate the elastic buckling strength and the crushing strength of the voussoir beam and to verify the failure mode of shear sliding. For application of the mechanism of the voussoir beam in mining operations, methods are described to predict the stability of a jointed roof and to design the dimensions of mining openings.IntroductionThe roof stability of an underground mine opening has direct effects on the selection of support methods, opening dimensions and, more importantly, on the safety of mining personnel. The prediction of the roof stability can be of importance in the design of a mining method and in mining operations. The jointed roof of mine openings in stratified rock can be stable under transverse load depending on the roof geometry and properties of the roof material and joints. The stability of this type of roof can be analyzed in terms of a voussoir beam which was introduced by Evans (1941) to study the strength of underground strata. Brady and Brown (1985) analyzed the voussoir beam and suggested that the mechanism of the voussoir beam could be used in the design of underground mine openings in stratified rock instead of the traditional continuous beam theory."

Jan 1, 1993

By J. P. McGeer

"With the ever-increasing flood of new science and technology has come a new approach to design. The combination of these factors has produced an ever-accelerating pace of materials substitutions.Examples to illustrate the points made above will be given. An overview of the current new materials fields will follow. Finally, the particular nature of the challenge for Canada will be discussed. IntroductionThere are a number of forces currently at work which make it mandatory that the Canadian resource sector re-examine its strategies and policies. The author thinks there need to be very significant changes in the business plans of Canadian mineral processing corporations. Current changes in our environment demand such a reaction.The changes in our environment include more rap id substitution of materials; a significant alteration in design philosophy; the global economy; and market saturation and market diversification in dev eloped countries.This paper will cover the changes and illustrate how they will affect the Canadian resource industry. It will show some of the ways that Canadian corporations are reacting to maintain profitability. Finally, some policy issues will be considered"

Jan 1, 1988

By Edward Martinez

Laboratory studies had shown that the magnetite contained in serpentine asbestos ore was not uniformly distributed. Ore particles containing chrysotiye fiber responded to a magnetic f field; particles containing little or no chrysotile were essentially non-magnetic. Larger-scale tests, run with a magnetic pulley being fed various asbestos samples ranging in size from 1/4 inch to 5 inches, confirmed that magnetic separation could be used as a concentration step in an asbestos mill. Magnetic concentration was installed at the Black Lake and National mills of Lac d'Amiante du Quebec and has allowed the extraction of lower-grade ore, increasing the life of the mines. In addition, preconcentration early in the flowsheet increased the value of the feed to the fiber recovery section. An increase in fiber production was achieved, as well as a decrease in maintenance costs due to removal of flow-grade tailings early in the flowsheet. Magnetic concentration of a coarse tailings from the mill resulted in recovery of additional fiber previously discarded to tailings.

Jan 1, 1979

By J. M. Menacho

As usually occurs in technological development, heap leaching knowledge has been built upon two parallel lanes, theory developed on fundamentals but relatively far from industrial applications, and operational know-how generated from empirical trial and error. As a contribution to close the gap between the above-mentioned lanes, the De Re Metallica process consulting group has been developing and applying fundamentalsbased modeling tools for industrial process design and process optimization of existing plants over the last ten years. As result, a library of models is now available with application to the whole production chain from blasting to electro winning. This presentation is centered in heap leaching and several real case studies are developed, showing how paradigms are broken when fundamentals are applied. Cu2007 - Volume IV (Book 1) The John E. Dutrizac International Symposium on Copper Hydrometallurgy Edited by P.A. Riveros, D.G. Dixon, D.B. Dreisinger, M.J. Collins Toronto, Canada,

Jan 1, 2007

"The gravimetric dust sampler is one of the tools now available to the industrial hygienists for determining the worker 's exposure to the numerous types of particulate matter that may be present in the workplace. The paper ' reviews the different sampling trains that can be used for the two major criteria for respirable dust and some of the sources of error in this dust assessment technique.IntroductionIt may be stated simply that the measurement of airborne dust in the working environment is done for one or two reasons: namely, for engineering control purposes and! or to evaluate the potential for toxicological insult arising from the inhalation of dust particles.This paper reviews the progress made in the development of dust-assessing instruments, particularly the gravimetric types designed to meet British and U.S. dust criteria , and discusses the limitations in their use for this purpose."

Jan 1, 1981

By M. P. Filion, K. Ferguson, L. L. Sirois

Acidic drainage is the largest single environmental problem facing the Canadian mining industry today. Technologies to prevent acidic drainage from occurring in wasterock piles and tailings sites, and on the walls of open pits and underground mines, need to be developed and demonstrated. There are two groups in Canada which have accepted this challenge: the national Mine Environment Neutral Drainage (MEND) program and the British Columbia Acid Mine Drainage (BCAMD) Task Force. This paper summarizes the activities of these two organizations.

Jan 1, 1990

By J. L. Blaylock

Normally, the hydraulic system and structures are considered to be unrelated items. In reality, the two cannot be separated because one affects and depends on the other to function properly. This paper explores the potential failure areas of hydraulic cylinders, and suggests possible methods to prevent failures from occurring. The use of high-strength low-alloy steel in frames is reviewed and the benefits discussed. Fabrication techniques and handling of material are noted in the hope that this knowledge will aid in the repair of frames in the field.

Jan 1, 1979

By E. M. De Souza

"The mining industry has developed a strong need for monitoring underground openings since bulk mining, used for increased productivity, has become the dominant mining method industry wide. The large stopes associated with bulk mining methods generally have to remain open and stable for several months, and monitoring is essential to provide an indication of ground response to mining and stope stability. The instrumentation data is also important during design optimization, which is used to maximize recovery, to minimize the dilution of ore and to minimize costs. Monitoring is essential to implement safety and is also critical in stope and mining sequence designs. The safety related aspects of monitoring include the protection of underground workers and the prevention of accidents by providing early warnings of the onset of any ground instability. The design related aspects of monitoring involve the development of data bases used for stope dimensioning and mine sequencing and timing and the monitoring of ground behaviour as a result of mining to verify the validity of the design thus allowing for remedial action during operation.Manual instrumentation data collection is, in a number of cases, economically unfeasible and, in many situations, dangerous as instrumented areas become inaccessible or extremely unstable. Also, because more and more complex instrumentation is being installed in underground operations, in several cases it becomes practically impossible to collect readings manually. The design and development of low-cost acquisition systems for mine wide monitoring would thus constitute an important step toward automation in excavation instrumentation. A unique menu-driven automatic 32-channel analog data acquisition and analysis system with a built-in rock failure warning mechanism has been designed and developed. This low cost acquisition system is capable of receiving, processing, displaying and storing the transmitted instrument data remotely and automatically. Computer software has been designed to provide data reduction and analysis immediately in the field and to automatically display results in graphical form for quick interpretation. Automatic data interpretation is used to show trends in rock mass behaviour and the system can be used to provide early warning of rock failure to the mine personnel working in there so that immediate remedial action can be safely taken."

Jan 1, 1992