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By H. Matsuoka, M. Kawata, K. Mitsuhashi, C. Tokoro, T. Kato

Copper sulfide minerals such as chalcocite, bornite, and chalcopyrite exhibit high floatability, thus they can be recovered as a froth product by adding only a collector in flotation process. However, when their surface is oxidized, the floatability decreases and the simple addition of collectors is no longer effective. In this case, flotation activators are required to improve the floatability. Sodium hydrosulfide (NaHS) acts as an activator for chalcocite and bornite by re-sulfurizing their oxidized surface portions. Nevertheless, the flotation conditions still require optimization in order to achieve a satisfactory recovery of copper minerals. This work addresses the study of the effect of pH and NaHS dosage on the flotation of a complex Chilean copper ore containing chalcocite, bornite, and chalcopyrite. Flotation experiments were conducted using a Denver-type flotation cell and by investigating the effect of two NaHS dosages (50, 100 g/t) and three pH values (8, 9, 10). Following this process, the surface interaction between the minerals and NaHS were analyzed using zeta potential measurements. INTRODUCTION In recent years in the mining area of metal resources, the complexity of ores and the fineness of grind required to liberate minerals have become serious problems. When ores are complex, several valuable minerals may interact with each other and reactions may become more complicated compared with an ore containing only one valuable mineral. Therefore, more processing steps may be required than for a simple ore. When the valuable minerals exist as fine grains, it is difficult to liberate them and more grinding time is required. Furthermore, the probability of collision of fine particles with bubbles in the flotation process declines and it takes much time to recover them. Flotation is one of the most applied methods to separate valuable minerals from unwanted ones using the difference of hydrophobicity (or hydrophilicity). In the flotation method, the air is fed to a cell filled with the pulp of the mineral of interest and agitation is implemented to introduce air and generate bubbles. The hydrophobic particles attach themselves to the bubbles and float along with the bubbles while the hydrophilic particles remain in the pulp. Copper sulfide minerals such as chalcocite (Cu2S), bornite (Cu5FeS4), chalcopyrite (CuFeS2) are widely known abundant copper resources. Generally, flotation is used to recover and concentrate these minerals. Copper sulfide minerals usually have high floatability. However when their surfaces are oxidized, their floatability becomes lower. When the sulfide surfaces are oxidized, activators are added before flotation to modify the surface property of the Copper sulfide minerals so that they can be floated. Sodium hydrosulfide, NaHS, is known as one of the activators. Zhao (2018) reported that NaHS is often used as a sulfurizer for oxidized sulfide minerals (Becker (2014), Clark (2000), Newell (2006), and Newell (2007)). In earlier work, the authors performed flotation tests on a sample of Chilean copper ore which contained chalcocite, bornite, and chalcopyrite using a Denver-type flotation apparatus. The sample was ground to P80 70 µm with a rod mill and ball mill. In these tests, the following conditions were used: natural pH (about pH 8.5), flotation time of 45 min, 60 g/t AP3477 (sodium diisobutyl dithiophosphate) as collector, and MIBC (methyl isobutyl carbinol) at appropriate dosage as frother. NaHS was applied at the dosage of 0, 67, and 120 g/t, respectively at the conditioning. The concentrates were collected at 6, 18, 30, and 45 min. The weights of the concentrates and tailing were measured and they were assayed for copper by ICP-AES (Optima 5300 DV, PerkinElmer Inc.). The flotation recoveries of the copper minerals were calculated from the results of MLA (mineral liberation analyser) (MLA 650, FEI) measurements.

Jan 1, 2019

By P. B. Marchant

"Considerable gold and silver values are lost to flotation tailing from both the South ern Tail orebody and the Main Zone orebody,The underlying mineralogical assemblage of the two ore types is quite different. This paper describes the research strategy employed to determine an economical method to scavenge gold and silver from flotation tailing.Much of the unrecovered gold in the Southern Tail ore is associated with arsenopyrite while silver losses are probably as unliberated tetrahedrite and minor silver-bearing sulphosalts. Processing alternatives tested include bulk sulphide recovery by flotation and gravity, selective pyrite-arsenopyrite separation, cyanidation, and oxidation pretreatments such as pressure leaching and bioleaching to enhance cyanidation response. Gold losses in the Main Zone ore are more closely associated with silver-bearing minerals, pyrite, and siliceous gangue and consequently respond more readily to conventional tank cyanidation. The 5 300 tid carbon-in-leach circuit to treat Main Zone flotation tailing is described in detail.IntroductionEquity Silver Mines Limited's open-pit silver mine, a 70% owned subsidiary of Placer Development Limited, is located 37 km southeast of Houston in north central British Columbia. The deposit consists of two major ore zones, Main Zone and Southern Tail (Fig. I). These zones are within a sequence of Cretaceous volcanic and sedimentary rocks striking 015 degree s and dipping 45 degrees west. Feasibility ore reserves were 28 million tonnes grading 106 g A g/t, 0.96 g Au !t and 0.38% Cu a strip ratio of 2.2 to I. A detailed mineralogical description has been presented and a comparison of the two ore zones is shown in Table I."

Jan 1, 1986

By Claudia Gasparrini

"Silver occurs in about 200 minerals in variable amount s. Silver ores usually have 5 or 6 and in some instances as many as 10 species of silver minerals. All these minerals may have different flotation and leaching properties and should be correctly identified for successful recoveries. Grain size and host minerals which are critical in gold recovery, are not always as important for silver minerals.IntroductionMineralogical factors affecting the metallurgy of silver are , as for other metals: (i) the silver-bearing mineral s ; (ii) their grain size, and when dealing with very fine sizes; (iii) their host minerals; and (iv) the association they form with the silver-bearing minerals. Of these, the silver-bearing minerals are more often the cause of problems during recovery as opposed to gold whose metallurgy is generally more affected by grain size and host minerals. The problems derive mainly from the complexity of the silver mineralogy: over 200 minerals exist bearing the element in major, minor and variable amounts.As a member of group I-B of the periodic table, silver forms extensive so lid solutions with the other two elements in the same group , copper and gold. It combines with sulphur, tellurium and selenium in covalent bonds and with chlorine, bromine and iodine in ionic bonds. Where the fluid composition, temperature and pressure during crystallization allow it, silver also combines with arsenic, antimony, lead, bismuth, tin, mercury, indium, thallium, and germanium in many instances as a minor element in sulphide , sulphosalt and native element minerals. Cations which silver replaces to a lesser extent than copper and gold are iron, manganese, zinc and probably nickel and cobalt."

Jan 1, 1984

By A. A. Burgoyne

"The McDame chrysotile asbestos deposit located near Cassiar in northern British Columbia isfound at depth and on trend to the southeast of the currently mined open-pit Cassiar asbestos deposit. The ultramafic rock hosting the McDame is serpentinized peridotite of the Upper Paleozoic Sylvester Group contained in an ophiolitic sequence preserved within a lower thrust sheet of the Sylvester Allochthon. The Sylvester stratigraphic package is a series of thrust slices composed of argillite, tuff and volcanic flows, diorite and serpentinite. Contacts between units are often fault-controlled.The McDame asbestos-bearing ultramafite is considered to represent a separate interleaved fault-bounded slice of rock distinct from the Cassiar asbestos deposit.Asbestos mineralization of the McDame deposit was discovered in /978. Exploration during /980 and /98/ focused on extensive underground drilling of the deposit and in /983 on geological mapping, airborne and ground magnetic surveys. In /984 a 622.5 m borehole was drilled with a 242 m intersection of McDame ultramafite of which the lower 15/ metres contain potentially economic chrysotile asbestos. The McDame deposit averages 90 m thick, trends north-south, dips easterly and plunges southeasterly. The deposit is estimated to contain geological reserves in the order of 62 million tonnes containing asbestos fibre similar in value to the Cassiar deposit.The McDame is considered a major world-class asbestos deposit. A decision to develop and mine the deposit will require further substantial underground exploration and evaluation. A + 1200 m exploration adit driven to the hanging wall of the deposit was undertaken in 1985 in anticipation of bulk sampling and diamond drilling in 1986."

Jan 1, 1986

By M. P. Brameld, G. Archambault, R. H. McCorkell

"The rates. J. at which materials emit radon are of interest in studies of the sources of radon in mines. buildings. soils overburden and other places where it may indicate the location of ore or be a health hazard. Here J values were determined by measuring the radon concentrations by means of scintillation counters or alpha-particle track detectors in chambers in which specimens were sealed. Errors in the measurements due to leakage from the chambers. lack of secular equilibrium in the decay series of the radon measured, or the limited rate of diffusion of radon from powders or within the chambers were shown to be insignificant or could be corrected. Scintillation counter measurements are highly reproducible; track detector measurements also appear useable and may be made on many small samples using small, simple chambers. J measurements were made for uranium ores, drill cores, standard CANMET pulps. concrete and gypsum board. Powdering of ores had little effect on their J values.IntroductionIn the mining and mineral sciences, radon (222Rn) is of interest chiefly for two reasons: in geochemical exploration for mineral deposits its presence in soil. overburden and water in more than background concentrations may indicate the existence and locations of uranium deposits and, if present in sufficient concentrations, it is a possible health hazard in mines, mills and other places where people live and work. The latter aspect of radon's role has received considerable attention recently(1,2,3,4,5), and surveys of soil-gas radon concentrations have been used for some time in searches for uranium deposits(6,7,8,9,)."

Jan 1, 1981

By R. W. Guill

"The Apex Mine is currently scheduled to be brought back into production by Hecla in the first quarter of1990. Its projected productivity rate will be exceptionally high for a small underhand cut and fill mine.The ore mined at the Apex Mine occurs within a pipe-like structure as a series of iron oxides containing both gallium and germanium, plus significant amounts of silver, zinc, lead, and copper.Ground conditions in and around the ore zone have dictated that unique approaches be utilized. To date, these have included a prototype 0.5 cu. yd diesel LHD, and the use of fibrous shotcrete in 4ft by 7ft headings, and the first pneumatically-placed cemented backfill in North America. Above all else, it is the combination of new technologies with a small and dedicated workforce which has allowed for the successful development of this ore body.IntroductionThe Apex Mine is an example of the typical small underground project. It has high grade, but low tonnage and is deposited in poor ground. In such cases, conventional planning and thinking generally results in an uneconomical evaluation and negative production decision. Fortunately, some unconventional thinking was allowed to take place during the planning and evolution of the Apex Mine development. The result now serves as an example of how such unconventional thinking can lead to the type of innovations described below.The job necessitated the development and use of new equipment and materials to execute a highly flexible underhand cut and fill mine design/pneumatic backfill concept, that must be constantly modified as different than assumed conditions become evident in and around the ore zone."

Jan 1, 1990

By Fernand Dubuc

"The New Pascalis property is situated in Louvicourt and Pascalis townships, about 200 km east of Val d'Or, Quebec. It is made up of 38 claims under option to SOQUEM since August I, 1981 during which time SOQUEM has earned a 60% interest. The property is underlain by archean basaltic volcanics that have been intruded along the west boundary by the Bourlamaque batholith, and by north -trending dykes.The 1982 disco very is related to the re-evaluation of a 1931-gold showing located in the southeastern part of the property, a combination of the presence of a weak IP anomaly at the eastern end of the showing and overburden stripping at that location, resulted in the discovery of a mineralized diorite dyke.The dyke, which strikes N 20 ° Wand dips vertically , has intruded E-W striking agglomerates. The dyke contains south dipping, gold-hearing quart z-tourmaline-pyrite veins that are distributed in a ladder-type arrangement. Visible gold may he observed in drill core, and is generally associated with pyrite porphyroblasts.Diamond drilling has outlined th e dyke for a strike length of 300 11/ and a width of about 10 m, Result s of this drilling indicate, to a depth of 155 m, reserves of 834 000 metric tonnes grading 8.25 g Au/t un cut or 5.38 g Au/t cut to on e ounce. However, four deeper holes have added depth extension to 400m. Also, west of the dyke and within 150 m, other promising gold values have been intersected within quartz-tourmaline veins associated with other parallel dykes."

Jan 1, 1985

By G. Ladouceur

"Northgate Patino Mines produces a copper concentrate assaying 22% Cu. Moisture content of the product averages 12.5% H20 when dewatering with conventional vacuum disk filters. Recent smelter contracts reflect higher energy costs and increased moisutre penalty charges. This situation forced Northgate to investigate possible alternatives such as rotary dryers and pressure filtration. After laboratory testing, it was found that pressure filtration could economically meet the smelter's requirements. Pilot plant testing was then undertaken and confirmed the laboratory test results. Based on these findings, a model I.S.F. 1500 x 28/22 I.R. Lasta filter press was purchased.This paper describes the Copper Rand dewatering flowsheet the operation of the press and the economics of the process.IntroductionNorthgate Patino Inc. operates 2 und erground copper mines and a 3300 ton per day concentrator located in Chibougamau, Quebec, some 425 miles north of Montreal and 300 miles northeast of Noranda, Quebec.Copper concentrate is produced at a rate of 250 tons per day and trucked to a C.N. siding 10 miles from the mill site and then railed to the Noranda Smelter.Until early 1981, moisture content of the concentrate at 12.5070 was acceptable since smelter penalty charges were relatively low ($0.10 per ton per unit over 10070 moisutre). In January 1981, a new contract was signed in which the penalty was raised to $1.10 per ton per unit over 8070 . This and the increasing truck and rail costs justified the change-over from vacuum to pressure filtration . The Lasta I.S .F. 1500 x 28/22 was then purchased and installed, and operation of the plant started in December 1981."

Jan 1, 1987

By D. R. Murray

"A promising long-term solution to uranium tailings reclamation has been the establishment of vegetation directly on the waste material. The soil profiles of areas vegetated for 0, 3, 8 and 10years are characterized as to the extent of soil development . The characteristics are compared with the visually interpreted soil profile. Organic matter content is presently the best analytical judge of soil development. Vegetation procedures have produced a build-up of organic matter in the top 10cm of tailings where natural microbial populations flourish. The CN ratio is high and the profile depth shallow, suggesting the need for additional fertilizer applications.IntroductionThe reduction of surface erosion and improved aesthetics of uranium tailings has been accomplished by the establishment of a vegetative cover. In 1971 research concentrated on developing methods of plant establishment at minimal cost and soil amendments on uranium tailings in Elliot Lake , Ontario. One process of stabilization used on a large scale was direct seeding of grasses and legumes into the tailings which had received only limestone and fertilizer treatments. Fertilizer additions were made for varying lengths of time in subsequent years to maintain the established cover.Maintenance-free vegetation would be possible once a soil profile developed with sufficient nutrient recycle and plant regeneration capabilities(1). Tailings vegetated in 1971, 1973 and 1978 that had received either 3 or 5 years of maintenance fertilizers were examined for soil development profiles. The extent of soil development and the relative effect of time and fertilizer would provide direction on reaching the goal of a self-sustaining cover.This paper is an abridgment of Division Report MRP /MRL 81-126 of the same title(2)."

Jan 1, 1984

By B. Van den Bogaert, K. Binnemans, T. Van Gerven

Europium is one of the most critical rare-earth elements due to the limited supply of this element combined with a high demand for red lamp phosphors. Therefore, the recycling of europium from end-oflife lamp phosphors has become increasingly important. Photochemical reduction of europium(III) to europium(II) and subsequent removal from rare-earth mixtures by precipitation as EuSO4 is a very selective and efficient method to recover europium from binary europium/yttrium solutions. It is shown that full separation of europium and yttrium is feasible from laboratory prepared non-equimolar Eu/Y mixtures up to a ratio of 1/20, which reflect the composition of red lamp phosphors. Optimal conditions were determined at pH 4 with isopropanol as a radical scavenger, which is a less harmful and toxic compound than the commonly used formic acid scavenger. Europium removal efficiencies of more than 95% were achieved, with a purity of 98.5% of the EuSO4 precipitate. The irradiance of the used light source, expressed in mW/cm2, has a large impact on the illumination time needed to remove europium from the solution. It is observed that higher irradiance results in a shorter induction time, i.e. a period during which virtually no europium is removed, and a faster removal rate once the induction time has passed. The photochemical separation technique was applied to recover europium from leached industrial red lamp phosphor (YOX) powder, with a Eu/Y ratio of 1/30. Europium recovery of 50% was reached with a purity of 96%, proving the feasibility of this method for the recycling of europium from end-of-life lamp phosphors.

Jan 1, 2016

By T. R. Bieler

"Hot forming and superplasticity in powder metallurgy aluminum alloys and composites is reviewed. The effects of alloy composition, particulate composition, size, and size distribution is summarized. The role of climb distance for recovery is described in connection with the size of strengthening phases. In materials with fine strengthening phases on the order of one micron or less, high strain rate superplastic deformation processes are likely. However, the quality of superplastic deformation depends on the prior processing history, and these effects are reviewed. Very few data describing the effects of hot forming history on post-forming properties exist, but some results emerging in the literature are compared.IntroductionHot deformation in aluminum based materials is done for several technological purposes, such as thermomechanical processing to alter mechanical properties of simple forms, and/or final shaping operations to produce a complex shaped part by means of extrusion, forging, or superplastic forming. In the interest of improving the mechanical properties of aluminum based materials, two microstructural design strategies are commonly used, dispersion strengthening, and composite strengthening. The introduction of fine, stable dispersions is commonly done for high temperature strength, and the dispersions are typically ceramic particles in the range of 10 nm to 1000 nm in volume fractions around 5 vol.% (Higashi et al., 1990; 1991a; 1991b; 1992; Bieler and Mukherjee, 1990; Otsuka et al., 1987; Bieler et al., 1991; Oliver and Nix, 1982). Alternatively, composite strengthening strategies using 10-40 v% of 3 µm to 40 µm ceramic particles provide high modulus and high strength aluminum based materials (Midling and Grong, 1995; Lloyd, 1994; Subramanian et al., 1995)."

Jan 1, 1997

By M. A. Vos

"Cretaceous sands and clays underlie an area of approximately 5,000 km2 in Northern Ontario, southwest of James Bay. The deltaic deposits occur as a wedge of continental sediments to the north of an east-trending fault scarp referred to as the Precambrian Escarpment. They rest on older sedimentary formations of the Moose River Basin (Jurassic, Devonian) and are covered by glacial tills and marine sediments of the Quaternary period. Outcrops are restricted to occasional exposure in the deeply incised riverbeds.In 1975 and 1978, drill programs sponsored by the Ontario Government provided new information on the extent and quality of the deposits. Fourteen holes at approximately 12-km intervals were drilled to a maximum depth of 189 m by reversed- circulation chip drill methods. Some core was obtained as well. Analytical results show that the thickness of Cretaceous deposits exceeds 100m in several instances. Abundant kaolinitic clay and quartz sand of glass-grade quality, both unique materials in Ontario, are available in an area where hydroelectricity and lignite resources combine to enhance the energy outlook.IntroductionThe presence of refractory clay in deeply incised riverbeds in Northern Ontario was known to geologists travelling the rivers as early as 1875. Robert Bell (1877) reports outcrops of clay and lignite on Coal Brook, a tributary of the Missinaibi River. E.B. Borron in 1880 collected a sample of clay from the bed of the Missinaibi River which H.H. Croft of the University of Toronto considered to be ""nearly if not quite, equal to the Cornish clay used in the manufacture of English porcelain"" (Keele, 1920, p. 42). The Cretaceous age of the clay, sand and lignite deposits was determined with the help of plant remains collected by Keele. He referred to the deposits as the Mattagami series, which later became the Mattagami Formation."

Jan 1, 1982

By T. R. Yu, D. B. Counter

"Kidd Creek Mines primarily employs sublevel blasthole stoping for underground mining operations. During pillar recovery in No.1 Mine and panel mining in No.2 Mine, the free standing fill exposures may reach a height of 100 m or more. Consequently, a competent consolidated rockfill has been required to fill the mined openings.Since 1976, a total of more than fifty stopes and pillars have been filled with over four million tonnes of backfill. Fill exposures, up to heights of 100 m, have stood up well after blasting adjacent to the backfill.The fill material consists of a graded aggregate, Portland cement and ground slag. Sand has been occasionally mixed in the fill material to serve as avoid filler. The aggregate is prepared in a fill crushing plant, transported underground through raises, and hauled to the filling stopes by conveyors in No. 1 Mine and by trucks in No.2 Mine.Two mixing methods are currently in use. No. I Mine utilizes the free fall of gravity; the fill materials are sprayed with cement slurry as the aggregate departs from the conveyor into a mixing culvert. The other is the use of a rotary mixer on a batch basis in No. 2 Mine.This paper describes the fill systems, filling operation s, and the backfill quality control practice, together with various testing results related to improving fill quality as well as reducing fill costs.IntroductionThe Kidd Creek minesite, located 27 km north o f the city centre of Timmins, Ontario, produces 4.5 million tonnes of copper, zinc, lead, and silver ores annually from its No. 1 and No.2 underground mining operations. Both mines employ a sublevel blasthole stoping method."

Jan 1, 1983

By P. R. A. Andrews, R. K. Collings

"In cooperation with le Ministère de l'Énergie et des ressources, Québec, le Centre de Recherches minérales, Sainte-Foy, Québec, and various silica producers, selected deposits of Quebec silica were identified in the southern region of the province and sampled to provide material for evaluation as glass and foundry sand by CANMET. The samples included both sandstone and quartz/quartzite. Head sample analyses ranged from 94.66% to 99.54% SiO2, 0.038% to 0.230% Fe2O3, and 0.16% to 4.51% Al2O3.Impurities included pyrite, iron oxides, and iron staining on quartz grains; carbonates as calcite; and alumino-silicates as clay and/or feldspar. Processing included size reduction to grain size, about 600 µm, by jaw, roll and cone crushers, and grinding in a muller-mixer. Removal of fines was achieved by attrition scrubbing and washing. Further removal of impurities was achieved by reverse flotation of iron oxide and alumino-silicate minerals employing both anionic and cationic collectors. Flotation resulted in a substantial improvement in the quality of most sands, the quartz concentrates analyzing 99.08% to 99.80% SiO2, 0.014% to 0.048% Fe2O3, and 0.06% to 0.49% Al2O3. Removal of iron oxide minerals was also investigated using the Sala HGMS. Iron oxide analyses of the non-magnetic fractions were comparable to the iron oxide analyses of the quartz concentrates obtained by flotation, 0.013% to 0.054% Fe2O3. On the basis of the samples submitted, silica from 5 of the 6 deposits studied has potential as source material for glass sand. Foundry tests showed that 3 of the 4 samples submitted for evaluation have potential as foundry sand."

Jan 1, 1987

By L. H. Rajala, K. H. Singh

"This paper presents the results of a detailed feasibility study carried out to investigate whether a low-grade deep underground mine of Falconbridge Nickel Mines Ltd., closed since 1975, could be made more productive and profitable by the introduction of new mining technology. For this purpose, recent advances in mine design and development concepts, larger and better designed machines, such as hydraulic drills, high-pressure down-the-hole machines, LHDs, new blasting concepts, more efficient and improved stoping methods, and ground control technology were considered. Technical and economic analyses incorporated the latest computer-based techniques. The mine was reopened in 1979 and the paper concludes with an assessment of actual progress and performance compared with that planned and forecast.IntroductionThe East Mine orebody, located between the Falconbridge Mine and Inco's Cryderman Mine in the Sudbury District of Ontario, has been in production since 1956. From 1956 to 1978, about 5.6 million tons of ore had been mined from this ore zone. The ore body is low grade and was developed as a cut-and-fill operation. Due to high operating costs, the mine has been shut down several times during economic downturns. The latest closure was in 1975 due to a lower demand for metal.In 1978, investigations were initiated to assess the economic and technical feasibility of mining this ore using new developments in mining technology. In this study, consideration was given to the application of bulk mining methods with a potential for higher productivity, trackless development utilizing efficient LHD machines and hydraulic drills, new blasting and fragmentation concepts, and new ground control technology. Advanced computer techniques, such as finite element, for mine design and rate of return with discounted cash flow analyses for the economic comparison- of various mining options were utilized for a rapid and comprehensive assessment during the feasibility stage."

Jan 1, 1981

By J. Bigu, M. G. Grenier

"Dust size distribution and aerosol size distribution measurements have been carried out in several Canadian underground uranium mines. In addition, dust samples have been analyzed for long-lived radioactive products of the U-238 and Th-232 natural decay chains using ex-spectroscopy and -y-spectroscopy techniques.From the data collected one may summarize: (a) most airborne particulates are of size below I u-m and 50% by mass are found above 1 u-m; (b) dust clouds are bimodal; (c) preferential deposition of radon (thoron) daughters takes place on airborne particulates in the sub -micron range at about 0.1 u-m; (d) deposition of radon (thoron) daughters is proportional to particle surface area; and (e) ex-spectroscopy and -y-spectroscopy of dust samples reveals the presence of U-238, Ra-226 and some of their short-lived and long-lived decay products.IntroductionExtended inhalation of airborne radioisotopes poses a potential health problem to occupational workers. Because of this, monitoring of radiation and dust levels for dose exposure calculation purposes is not only recommended but in most cases mandatory.CANMET (Energy, Mines a nd Resources Canada) has long since been engaged in a comprehensive monitoring program aimed at determining dust concentrations in the respirable size range, aerosol concentration in the sub-micron range, and in the radioactivity associated with these particulates in underground uranium mines. Measurements have been carried-out with gravimetric dust samplers, dust size selectors (including a horizontal elutriator , a fineparticle spectrometer and Nuclepore* filters of different pore sizes) and a condensation nucleus counter(1 – 6). Inactive and active working sites have been monitored according to some typical mining operations. A summary of these data has been given elsewhere(3- 5)."

Jan 1, 1984

By L. Dekker

"In 1979 Chevron Standard Limited and Irving Oil Limited intersected a thick, high-grade sylvinite zone in the Windsor Group in the Chevron Irving Malagawatch No. I well in central Cape Breton. This well was the third and final hole of a program designed to evaluate a non-commercial oil discovery made by Chevron Standard's Mineral Staff in 1978 while carrying out base metal exploration. Nine holes were subsequently drilled to evaluate the significance of the potash discovery. The delineation drilling proved the Malagawatch structure to be complex with the potash zone showing erratic grade and thickness distribution. Based on the drill information the potash accumulation at Malagawatch is uneconomic, however, other salt ""structures"" in the Bras d'Or Basin may in time prove to have better potential.History of DiscoveryIn 1972 Cuvier Mines discovered the Gays River lead-zinc deposit (MacEachern and Hannon, 1974) which prompted Chevron Standard's Minerals Staff to carry out a study of the Windsor basins in Nova Scotia (Figs. I and 2). As a result of this program several carbonate-hosted lead-zinc prospects were identified in the basal Windsor carbonate; one of these was at Malagawatch on Cape Breton Island . In 1978, after preliminary exploration surveys, a diamond drill program commenced consisting of 5 BQ holes (Fig. 3), three of which tested the basal carbonate. Instead of the reefoid bank facies of the Gays River Formation (Giles et al., 1979), the favoured host for economic base metal mineralization, this carbonate was developed as a laminated, pelletoidal, lime packstone more characteristic of the facies equivalent Macumber Formation (Schenk, 1967). While drilling one of these holes, No. 3-78, oil scum was intermittently detected on the drilling mud. The hole was abandoned at 191 m in anhydrite, without having reached the basal limestone."

Jan 1, 1985

By L. C. Galloway, P. M. Tiley

"Some progress has already been made in defining the parameters which will determine the performance of a guidance system in a mine shaft. Very little information is available, however, to help designers or operators predict the effects of varying these parameters in new or existing installations.The experience we have gained from monitoring a variety of installations has led to the development of a model which simulates the motion of a conveyance as it moves through a mineshaft, restrained by fixed guides.This paper presents a general analysis of the performance of the guidance system used in several installations, as well as a detailed description of the problem encountered at one mine and the steps taken to solve it.IntroductionOur company has investigated in some depth the problems that arise in the guidance of mine hoist conveyances.We have a telemetering accelerometer which we obtained to test mine hoist brakes. Frequently, during brake tests, the mine owners request us to use this instrument to measure the lateral motion of the conveyance ""to check guide alignment"". We have made such tests in shafts that have guide s of different kinds, including wooden guides, steel rail s and tubular steel guides. From these tests, we have gained some valuable information about guidance systems.In a well-aligned guidance system that is designed within common and well-known practice, the conveyance will experience very little shock most of the time. However, on rare occasions, shocks up to .5 g will occur. That is, the conveyance exerts a force of up to half its loaded weight on the guide. If the guide slips or is damaged by this force, it will be misaligned for future trips and become the cause of future shocks. In time, the whole guidance system can become misaligned."

Jan 1, 1982

By L. C. Galloway, P. M. Tiley

"Some progress has already been made in defining the parameters which will determine the performance of a guidance system in a mine shaft. Very little information is available, however, to help designers or operators predict the effects of varying these parameters in new or existing installations.The experience we have gained from monitoring a variety of installations has led to the development of a model which simulates the motion of a conveyance as it moves through a mineshaft, restrained by fixed guides.This paper presents a general analysis of the performance of the guidance system used in several installations, as well as a detailed description of the problem encountered at one mine and the steps taken to solve it.IntroductionOur company has investigated in some depth the problems that arise in the guidance of mine hoist conveyances.We have a telemetering accelerometer which we obtained to test mine hoist brakes. Frequently, during brake tests, the mine owners request us to use this instrument to measure the lateral motion of the conveyance ""to check guide alignment"". We have made such tests in shafts that have guide s of different kinds, including wooden guides, steel rail s and tubular steel guides. From these tests, we have gained some valuable information about guidance systems.In a well-aligned guidance system that is designed within common and well-known practice, the conveyance will experience very little shock most of the time. However, on rare occasions, shocks up to .5 g will occur. That is, the conveyance exerts a force of up to half its loaded weight on the guide. If the guide slips or is damaged by this force, it will be misaligned for future trips and become the cause of future shocks. In time, the whole guidance system can become misaligned."

Jan 1, 1982

By G. A. Kosick, M. Freberg, L. A. Kuehn

"Highly variable and higher than forecast lead miff feed grades were problems experienced at the Polaris Concentrator. Limited flotation capacity and poor operating flexibility prevented the plant operators from overcoming these difficulties, and resulted in grades and recoveries which were lower than necessary.Two column cells were integrated into the lead circuit in an effort to give the operators the tools they required to achieve the best grades and recoveries possible, regardless of the miff feed grade. Installation of the column cells increased lead concentrate grade from 76% to 79.3% Pb, and increased lead recovery from 9/% to 91.3% Pb.This paper reviews the design, development and operation of column flotation cells in the lead circuit at the Polaris Mine.IntroductionThe Polaris Concentrator was constructed in 1980 on a barge in Trois Rivieres, Quebec, and towed to its pre sent location on Little Cornwallis Island, Northwest Territories, about 1450 km from the North Pole. The plant presently treat s about 2800 mtpd of new feed with average feed grades of 3010 Pb, 13% Zn and 5% Fe. Current production averages 36 000 tonnes of lead concentrate and 220 000 tonnes of zinc concentrate annually.The barge design and min e location dictated that the concentrator .be compact with very little unused floor space. As a result, flexibility was limited in terms of expanding the plant.Mill feed grades were highly variable and above forecast and the lead flotation circuit was found to be under capacity. This caused continued overloads in the lead cleaning circuit, resulting in low concentrate grades and recoveries. It was evident that an increase in lead flotation capacity and flexibility was necessary. The existing floor space did not allow for the installation of additional conventional flotation cells, but one alternative was the installation of column cells."

Jan 1, 1988