Search Documents

By W. B. Coker

A helicopter-mounted lake-sediment and lake-water survey was carried out over Grenville rooks in the Renfrew area (parts of Renfrew and Lanark counties) during four days of October, 1975. In the course of this survey. 1150 square kilometers were covered, with 246 lake-sediment and 276 lake -water samples collected from every body of water on which the helicopter could land. Sample sites, which averaged one per 4.6 square kilometers, included lakes, ponds, beaver ponds, swamps and marshes. Lake-sediment samples were taken using a G.S.C. sampler. Waters were collected directly into polyethylene bottles. At each sample site , surface and bottom-water pH, dissolved oxygen content, conductivity and temperature were measured using a Martel. Water Quality Analyzer. The lake sediments were air dried and then ball milled to pass a minus 80-mesh sieve. Lake sediments were analyzed for U by delayed neutron activation and for Mo, Cu, Zn, Pb, Fe, Mn, Ni and Co by atomic absorption techniques. The organic content of the sediments was determined by loss on ignition at 450 °C. Lake waters were acidified with nitric acid on the day of collection. The U content of the water s was determined by fluorometry; the Cu, Zn, Pb, Fe, Mn , Ni and Co contents of the waters were determined by solvent extraction - atomic absorption techniques. A close relationship was found between bodies of granitic, syenitic and pegmatitic bedrock and elevated U levels in the lake sediments. The Hurd Lake and White Lake granitic intrusive were encompassed by an annulus of higher U activity. Field inspection revealed that the U concentrations occur within a zone which may represent a contact metamorphic aureole. Within these complexes, anomalous concentrations of U appear to be associated with Mo. Information derived from the lake-water data reinforces the geochemical distributions outlined by the lake-sediment survey . This survey was carried out in order to develop optimum sampling and analytical procedures for geochemical reconnaissance of the Grenville Province that may be carried out under the auspices of the Uranium Reconnaissance Program.

Jan 1, 1977

By Cardm Jeffrey W.

The decay of 222 Rn yields a series of short-lived decay products which become attached to the surface of a plate or wire exposed in a 222Rn-bearing atmosphere. The alpha-activity of two of the decay products, 218Po and 214Po, can be measured by simple counting techniques. This phenomenon may have direct application to uranium exploration. Laboratory studies have shown that: (a) radon decay products can be collected on a wide variety of materials (including various kinds of metals and plastics); (b) activity increases as a function of the surface area of the 'collector; and (c) the collection of the decay products is enhanced by applying a negative charge. The new technique was used in situ to delineate the anomaly above the South March uranium-copper occurrence. A related technique was developed to measure radium in soil samples. The results of both studies compared favourably with those obtained from conventional methods.

Jan 1, 1979

By Les Johnston

_ BACKGROUND - About EPCOR - Genesee Generating Station - Phase 3 Expansion _ TECHNOLOGY SELECTION - Selection Criteria - Combustion Options - Flue Gas Emission Control Options _ STAKEHOLDER VIEWS _ PROJECT STATUS _ EPCOR is an integrated utility company for water, gas, electricity and technology services. _ EPCOR has about 1.6 million customers in Alberta, Ontario, Manitoba, BC, and the U.S. Pacific Northwest. _ EPCOR Generation Inc. operates three power stations in Alberta which were in operation before deregulation, including the coal-fired Genesee Generating Station. _ EPCOR Power Development Corporation owns generating stations in Alberta, BC and Washington State and will be building the Genesee Phase 3 expansion.

May 1, 2002

TABAKOTO / SEGALA ? Annual gold production approximately 100,000 oz ? Debt free ? Unhedged ? Combined surface reserves 949,000 oz ? Combined 9 year life Tabakoto open pit reserve 568,000 oz (3.4m tonnes @ 5.26 g/t Au) Segala open pit reserve 381,000 oz (3.98m tonnes @ 2.98 g/t Au)

May 1, 2006

By C. Stapel, AA Groningen, R. J. De Meijer

"In recent years the Environmental Research Group of the KVI has been developing a number of radiometric techniques that may be employed in mineral sand exploration. These techniques involve: radiometric fingerprinting for assessing sand provenances and mineralogical composition; thermoluminescence for dating and provenance determination of sediments; a towed seabed detector to map seafloors for radiogenic heavy minerals and assessing heavy mineral volumes; and simplified transport mechanism models to explain and predict heavy mineral concentrations.All techniques exploit the property that heavy minerals as a group contain concentrations of naturally occurring uranium and thorium that are a hundred to a thousand times higher than in light minerals. In this paper the physics of a number of methods will be described together with a number of results. Based on these results potential applications to mineral exploration and mining are discussed."

Jan 1, 1994

By Charlie Graham, Helen Shang, Ashley Scott, Andrew Hall

"Approaches to Energy Recovery• Upgrading for electricity generation - steam turbines• Direct extraction- process improvement or space heating- support medium for animal or plant growth– fish or microalgae• Heat pumps- space heating/coolingWater Energy Grades• High (150+ °C) - electricity Generation• Medium (26 to 121 °C) - direct extraction• Low (5 to 18 °Celsius)- use of heat pump is required• Temperatures between zones will depend on circumstances for best use."

Jan 1, 2012

By Ike Isagon

Outline 1.Background Sudbury Backfill Operations 2.Alternative Binder 3.Alternative Binder Trial Process Flow Diagram ?Laboratory Results ?Plant Trial ?Final Evaluation and Approval ?Management of Change (MOC) 4.Economics 5.Conclusion 6.References and Acknowledgements

Nov 1, 2011

By M. Leroux, S. R. Rao, J. A. Finch

"Poor Pb-Zn selectivity during Pb flotation in laboratory tests on a Mississippi Valley-type Pb-Zn ore was traced to apH effect. In the pH range, 9.5 to 11.0 sphalerite floated readily without copper activation. Compared to sphalerite flotation with copper activation this procedure gave equivalent selectivity but reduced flotation rate.Possible mechanisms of this sphalerite flotation without copper activation are discussed. Activation by Fe(OH)2 is suggested, the Fe- + ions being derived from superficial oxidation of pyrite in the ore. IntroductionGalena and sphalerite commonly occur together. A typical procedure, using xanthate collectors, is to float the galena first, at pH - 8, followed by flotation of sphalerite after activation with copper (II) sulphate at pH - 10 (to depress pyrite).Flotation tests following this procedure in an undergraduate laboratory course with a Pb-Zn ore from Polaris failed to achieve consistent selective flotation of galena. Occasionally a considerable amount of sphalerite, even though unactivated with CUSO4, floated. This was traced to accidentally high pH. A systematic study was carried out which revealed that sphalerite floated readily in the pH range 9.5 to 11.0 without activation by CuSO4 This paper describes the results of the study and discusses a possible mechanism of this flotation of sphalerite."

Jan 1, 1987

By Morris J. Viljoen, Young. David R.

"Abstract -The zone of economic interest at H.J . Joel Gold Mine is the VS5/Beatrix Composite Reef, a quartz-pebble conglomerate of Archean age. The reef occurs at the base of the Eldorado Formation, Central Rand Group, of the Witwatersrand Supergroup. At !east three stratigraphically distinct conglomerates form this economic zone. In order of deposition these are the Footwall, Beatrix, and the VS5/Beatrix reefs. The Footwall and Beatrix reefs are equated with the Aandenk Formation with transport directions toward the northwest, whereas the VS5/Beatrix Reef is of Eldorado age, with transport directions toward the south. The change in the drainage direction was caused by a major basin-wide tectonic event that occurred prior to the deposition of the Eldorado Formation. The Beatrix Reef was formed in a proximal, braided, fluvial environment by a process of aggrading gravel bars between channelways. The VS5/Beatrix Reef was formed by the desegregation of pre-existing Beatrix Reef with the introduction of new material containing much shale detritus and is seen to have been deposited in a more ·distal, braided, fluvial environment, similar to the Beatrix Reef.The average gold concentrations are different for each conglomerate; the Beatrix at 32.1 ppm Au, the Footwall at 24.4 ppm Au, and the VS5/Beatrix at only 12.4 ppm Au. A sedimentary gold concentrating process related to higher energy braid channels was primarily responsible for these high gold grades. Not only the basal unconformity surface, but also, internal degredation surfaces, were prime sites for concentration. An understanding of the spatial distribution of these differing conglomerates and their braid channels forming the economic reef zone is necessary in predicting ore grades for future mining."

Jan 1, 1994

By C. Schuffeneger

"The design of SAG milling circuits for mining projects requires the incorporation of the energy consumption considerations and the evaluation between different flexibility-adding options to absorb the time-dependent variation in the ore lithology. In order to expand the focus of the engineering design, a higher level of deepness and quality in the baseline information must be achieved to elucidate all of the constraints on throughput, energy consumption and product quality generating a design optimization consistent with an integrated vision of the process. This paper presents a review of a collection of typical examples of the copper and gold mining project in the Chilean Andes, in which both process and energy efficiency criteria are considered when the focus is to deliver an integral solution that incorporate those areas in the design. The intensive use of energy in the SAG milling, the process continuity and the quality of the product are a function of the proper design and selection of grinding equipment and plant layout, aligned with the mining plan and associated with projected future expansions and production increases.INTRODUCTION Autogenous and Semiautogenous grinding technology, large diameter and short length mills, begins with the Handsel design. During the decade of 1930’s, Handsel-Hardinge studies led to cascade mill development. Nowadays, 80 years later, continuous improvements in design and technology have been conducted to a completely new generation of gearless SAG mills that have led to an increasing capacity at the concentrator plants. Considering the existing alternatives, SAG mills are the most implemented option for the grinding circuit today. This work presents a review of the SAG mill implementation parameters and circuit considerations and its correlations in the most recent projects in Chile with an ore treatment capacity above 50 ktpd since the decade of the 90’s up to now. From this period, the tendencies will be analyzed using project design data. Based on process design information, the recent SAG mill history in relevant projects related to the new generation of commercial SAG mills, technical associated considerations and performance will be discussed. Circuit selection based on energy utilization will be revised to bring up a more holistic perspective on the SAG mill circuit design concepts. As is now well known, the heart of every concentrator plant are the grinding mills. Higher demands on throughput, availability and power consumption optimizations require not only high performance electrical equipment but also a well selected grinding circuit. The energy efficiency issues associated to the circuits design will be reviewed."

Jan 1, 2012

By J. Asfahani

"The Schlumberger configuration used in geoelectrical sounding is slightly adapted here to obtain reliable data for both shallow and deep penetration depths from the same survey. In this configuration, two kinds of current electrode half-spacings are used: the first enables construction of vertical electrical resistivity sounding (VES) curves for shallow depths (<50 m), and the second for depths =250 m. For a given VES location, two field curves are measured and interpreted using two standard approaches. Practical characteristics of such a modified configuration are illustrated with two field applications in Syria. The first aims to characterize the structure of Quaternary and recent deposits in the Al-Ghab depression region, and the second deals with exploration for phosphatic sedimentary units in the Al-Sharquieh mine. La configuration de Schlumberger normalement employée dans les levés géoélectriques a été légèrement modifiée afin d’obtenir des données fiables à faible et forte profondeur durant le même levé. Dans cette nouvelle configuration, deux types de demi-espacements des électrodes sont utilisés : le premier permet le développement de courbes de sondage de résistivité électrique verticales (REV) pour les faibles profondeurs (<50 m), et le second atteint des profondeurs =250 m. Pour une localité REV donnée, deux courbes de champs sont donc mesurées et interprétées grâce à deux approches standardisées. Les caractéristiques pratiques de cette configuration modifiée sont illustrées par deus exemples d’application en Syrie. Le premier vise la caractérisation de la structure des dépôts Quaternaires et récents de la région de la dépression d’Al-Ghab, et le second traite de l’exploration pour des unités phosphatiques sédimentaires à la mine Al-Sharquieh."

Jan 1, 2009

By P. J. Sylvester, D. H. C. Wilton, R. I. Wheeler, M. A. E. Huminick, D. Evans-Lamswood

"Abstract — Systematic characterization of the mineralogy of massive sulfide ore deposits can provide valuable insights into ore genesis and metallurgical processing that would not be apparent otherwise. We describe a method wherein (1) normative mineral abundances are calculated from whole-rock chemical assays using an algorithm, (2) the results are cast in block models, (3) the results are then verified with automated image analysis of a subset of samples prepared as grain mounts by backscattered electron imaging and X-ray mapping on a scanning electron microscope, and (4) those verified results are integrated with textural data determined by optical microscopy.The technique is applied to the magmatic Ni-Cu-Co sulfides of the Ovoid orebody, based on geochemical assays of 3175 whole-rock samples. Three principal ore zones are defined in the Ovoid. Type I ore occurs in the center of the deposit; it is magnetite-rich and pyrrhotite-poor with intermediate contents of pentlandite and chalcopyrite. Type II ore surrounds Type I ore and is pentlanditechalcopyrite- rich with intermediate contents of pyrrhotite and magnetite. Type III ore occurs at the base and along the outer periphery of the northern part of the orebody; it is pyrrhotite-rich and chalcopyrite- poor with an intermediate content of pentlandite, and a low-to-intermediate content of magnetite."

Jan 1, 2012

By Sylvie Brassard

Available information ?? InfoMine: mineral properties ?? Metals Economics Group: budgeted exploration expenses ?? MineScan: Canadian and American Mining Companies ?? Statistics Canada: Canadian Direct Investment Abroad, by Sector in the world OR all sectors by Country

May 1, 2008

By Xuanxue Mo, Zengqian Hou

"Abstract -Yidun Island Arc in Sanjiang Region is one of the important Kuroko-type volcano­ genic massive sulfide deposits (VMS) districts in southwestern China. Tectonically, the region is situated in the eastern portion of the Tethys orogenic belt, and is a late Triassic extensional island-arc. The island-arc underwent earlier arc construction, intra-arc rifting, later arc construction and back­ arc spreading during its evolution and formed a complete trench-arc-basin system, i.e., the Ganzi­ Litang suture zone, forearc basin, outer arc, intra-arc rifting zone, inner arc and back-arc basin from east to west across the island-arc.Kuroko-type VMS deposits and occurrences discovered so far are limited to within the intra-arc rifting zone of the Yidun Island Arc and tend to occur in groups or clusters distributed in separate fault­ bound basins; e.g., Zengke, Gacun and Xiangcheng basins, in which submarine volcanic rocks, especially bimodal volcanic suites, were extensively developed. The VMS deposits formed in the waning stages of volcanic eruption in the late Triassic and are hosted in the uppermost section of acidic volcanic rocks (rhyolitic-dacitic) within a bimodal suite. The orebodies are associated with these host rocks: rhyolitic-dacitic pyroclastic rocks and exhalites and chemical sedimentary rocks.Ali VMS deposits in Sanjiang are of the Zn-Pb-Cu type. The architecture of the deposits is two­fold, consisting of concordant lenses and layers of massive sulfides and an underlying discordant stockwork. Ali deposits show metal zoning. The hydrothermal alteration related to mineralization is strong and asyrnmetrical, and is found dominantly within the stockwork zone and host rocks surrounding the ores. There are two alteration patterns: (1) chloritization - sericitization - silicification from outer sides to core of the alteration pipe; and (2) silicification + sericitization - silicification + carbonate from the lower to upper part of the alteration pipe_The mineralization temperatures of ore-forming fluids vary in the range 200°C to 335°C. Thermal evolution of the fluids displays temperature profiles that first increase and then decrease with progression of mineralization processes. The majority of black-ore minerais (Groups I and II) formed during intensifying stages of hydrothermal activity, and the majority of serni-yellow-ore minerals (Group III) formed during a thermal maximum . There followed the formation of fine-grained black-ore minerals (Group IV), which interacted with barite layers during decreasing temperature phases.Oxygen and hydrogen isotope studies show that the sources of ore-forming fluids for the Kuroko­ type VMS deposits are two-fold: seawater and magmatic hydrothermal solutions, represented by the Kuroko deposits in Japan and Kuroko-type VMS deposits in Sanjiang, respectively. In the latter case the hydrothermal solutions reacted with host rocks and mixed with cold seawater percolating downward, and circulated through volcanic rocks resulting in development of alteration zones and formation of ore minerals in Kuroko-type VMS deposits."

Jan 1, 1993

By Phil Keele

Canadian Natural ??Business Approach Efficiency and Execution ?Drive to be the low cost producer ?Focus on exploitation ?Augment exploitation with strategic acquisitions ?Maintain Discipline and Strength while Delivering on the Defined Plan ?Maintain flexibility and control allocation of capital ?Strive for balance (asset portfolio) ?Maintain financial strength

May 1, 2010

By P. R. Day, W. K. Webster

"The introduction of large boreholes underground initially involved taking the techniques of open-pit bench blasting to the production stope, but with deeper boreholes and narrower stopes more controlled techniques must be developed in order to maintain good stope walls and prevent dilution of ore or structural damage to pillars due to blasting overbreak. The points discussed are drilling accuracy and drill pattern, the relationship between open-pit wall control and underground mining, the varied explosives products and initiation devices available, and some of the many ways that variations in loading, such as deck charging, etc., can produce desirable results.IntroductionThe use of large-diameter blastholes for underground mining began ten years ago and today they are widely employed in a variety of orebodies and stope configurations. These big blastholes, which range in size from 4.5 to 8 inches in diameter, were originally employed in the same manner &apos; as open-pit bench blasts; that is, the stope was silled out to full width and all holes were drilled vertical and parallel. This was suitable for competent, massive orebodies, however the popularity of the big drills saw their usage in more narrow stopes, often with poor ground conditions. The dipping orebodies and small drill sublevels resulted in inclined drilling.Today, there is full-ring drilling of 4.5-inch holes. Some 6.5-inch holes are drilled up to 350 feet deep. A 350-foot borehole may contain 6000 to 7000 pounds of explosive. The detonation of this size of charge weight within the confines of an underground stope can have considerable effect on the stability of stope walls and adjacent pillars. Obviously, precautions must be taken to minimize the damage which would result from the large charge weights possible with these big boreholes."

Jan 1, 1982

By A. Desbiens, A. Pomerleau

During the summer of 1994, a new PID-based control strategy was installed on line B of the grinding circuit at the Kidd Creek Division of Falconbridge Ltd. Part I of this paper described the methodology used to select the appropriate control strategy using a phenomenological dynamic simulator. Part II presents the implementation of the control strategy. Prior to the controller installation, it was necessary to solve various problems related to the process, such as a cyclic behaviour of the rod mill feed tonnage, a problem related to the mill water source and the calibration of the flowmeters. Once these problems were solved, the control strategy was accomplished in two steps. Step 1 corresponds to the installation of control loops to regulate the pump box level and the cyclone overflow density. Step 2 describes the implementation of a loop to control the cyclone feed density. According to Part I, a loop to control the circulating load is also part of the original design. However, reasons are given to explain the rejection of this loop. For both steps, technical procedures such as filtering, process identification and controller tuning are detailed. Finally, the operator’s interface is briefly described.

Jan 1, 1997

Mine Evaluation Engineering , Operational and Social evaluation. Focus is on what opportunities are available. Social ??History ??Past Management Practices ??Community / Available labor force Mining Method / Equipment ??Competent rock ?little support required, no backfill ??Shallow mining ?ramp mining, no shafts or hoisting ??Large scale mining potential ??Simple rock breaking and crushing on surfaceMill Process ??Straightforward gold liberation process Create a Plan / Create a Team Following the feasibility 44-101. Key people were hired and a full operational Business Plan was developed. Focus is on how to get the job done. ??Scoping Study / Pre-Feasibility / Feasibility ??Operational Business Plan ??Hire key people ??Purchase key equipment

May 1, 2006

By M. C. Bétournay

Hydrogen fuel cells are a known technology, having been applied to stationary (e.g. equipment, buildings, and power plants) and vehicle applications (e.g. transit buses and space shuttles). There is currently a growing need to provide alternate power systems to diesel fuel for underground mining vehicles to improve underground air quality and reduce production costs and greenhouse gas emissions. To date, however, fuel cells have not been exposed to underground mine air and physical conditions. A testing program was carried out to provide information on the vulnerabilities of fuel cells as part of a number of proof-of-concept projects to apply hydrogen power to underground mining vehicles. The fuel cell type of choice for the industry, the proton exchange membrane, would function at the range of surface operations, and use hydrogen that is stored under low pressure and risk. A small fuel cell stack was tested in a cooperative project between CANMET, the Fuelcell Propulsion Institute, Inco, the Ontario Ministry of Labour, Sandia National laboratories, and H-Power. This article will review the tests carried out to measure the effects from high humidity, mineral dust, diesel emission gasses and diesel particulate matter, as well as from shock and vibration provided to the unit in underground conditions at Inco?s 175 Orebody minesite and Stobie mine. The test results provided will show that the unit was not affected by the underground conditions; physically and electrically, the unit performed without any reduction in operation or adverse effects imposed

May 1, 2005

By G. Bonnell, W. Lidkea, M. C. Bétournay, E. Edwardson

"Hydrogen fuel cells are a known technology, having been applied to stationary (e.g equipment, buildings, and power plants) and vehicle applications (e.g transit buses and space shuttles). There is currently a growing need to provide alternate power systems to diesel fuel for underground mining vehicles to improve underground air quality and reduce production costs and greenhouse gas emissions.To date, however, fuel cells have not been exposed to underground mine air and physical conditions. A testing program was carried out to provide information on the vulnerabilities of fuel cells as part of a number of proof-of-concept projects to apply hydrogen power to underground mining vehicles. The fuel cell type of choice for the industry, the proton exchange membrane, would function at the range of temperatures encountered in underground and surface operations, and use hydrogen that is stored under low pressure and risk.A small fuel cell stack was tested in a cooperative project between CANMET, the Fuelcell Propulsion Institute, Inco, the Ontario Ministry of Labour, Sandia National laboratories, and H-Power. This article will review the tests carried out to measure the effects from high humidity, mineral dust, diesel emission gasses and diesel particulate matter, as well as from shock and vibration provided to the unit in underground conditions at Inco’s 175 Orebody minesite and Stobie mine. The test results provided will show that the unit was not affected by the underground conditions; physically and electrically, the unit performed without any reduction in operation or adverse effects imposed."

Jan 1, 2005