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By T. Tsutsumi, S. Kukino

"During the diametrical compression test, the tensile stress generated near the loading plate is influenced by the contact area between the loading plates and specimen. However, very few studies have determined the contact area. Theoretical or analytical models have shown that for an orthotropic material (i.e., with material properties that differ along each of three mutually orthogonal twofold axes), the maximum tensile stress is generated at the center of disk when the angle of the principal material direction to the loading direction is close to ?/4. The maximum value is almost constant, regardless of the contact area. Conversely, the maximum tensile stress is generated near the loading plate when the angle between the principal material direction and loading direction is small. The maximum value decreases as the contact area increases. Therefore, in the latter case, the influence of the contact area on tensile strength measurement of is significant.In previous studies, the distribution of stresses applied on the loading plate is assumed to be a uniform load. In reality, the applied stress is highest at the center of loading plate and seems to decrease with distance from center. The applied load disappears at the edge of loading plates. In this study, in order to satisfy this boundary condition on the loading plate, the cosine curve is adopted as the distribution of load applied on the loading plates in a theoretical model of the diametrical compression test. Furthermore, the elastic solution using boundary conditions shown in this study is used to obtain the tensile stress distributions on the loading axis for an orthotropic circular plane. These distributions are compared with empirical results obtained under uniform loading with a loading plate or concentrated loading in previous studies."

Jan 1, 2015

By A. Zorkovská, S. Castro, P. Baláž, Z. Bujnáková

Enargite (Cu3AsS4) belongs among refractory copper minerals with very low hydrometallurgical extractability of copper. An application of enargite leaching in acid solutions leads to simultaneous dissolution of copper and arsenic and the final leach solutions have to be treated for the separation of both elements. However, the alkaline leaching of enargite is selective. Arsenic passes into leach while produced copper sulphide represents the raw material suitable for pyrometallurgy. The hydrometallurgical processing of mineral can be influenced positively by mechanochemical route. We have shown that more than 80 % of arsenic can be extracted from enargite concentrate by atmospheric alkaline leaching at 95 °C when mechanical activation in an attritor is applied. The produced Cu2S can be further treated with elemental iron where mechanochemical intervention is applied in the second stage of enargite processing. The final product forms Cu/FeS nanocomposite from which copper nanoparticles can be easily separated. The illustrated concept of copper obtaining from copper sulphide is an example of so-called “dry” processing, as reactions in gas and liquid phases are excluded. This concept of environmentally friendly metallurgical processing can be classified as an impetus for novel technology to produce copper from enargite concentrates.

Jan 1, 2012

By Euler De Souza

The authors conducted a study of backfill practices in underground mines across Canada to assess the current state of backfill usage and to overview potential hazards associated with backfill practice, from preparation to transportation to placement. The primary aim of this study was to cover each component of a typical mine backfill system, and to identify potential incidents leading to the disruption of backfilling operations and any associated corrective actions. This paper, Part I of the study, deals with surface operations consisting of backfill material supply and backfill plant preparation. Part II of the study, which deals with underground operations consisting of backfill transportation and backfill placement, is also presented in these proceedings. A review of safety measures associated with current backfill operations and recommendations for procedures of best practice that should be implemented to reduce fill-related hazards in all mine backfill workplace environments are presented. In general it has been found that system failures normally lead only to minor losses to the operations.

May 1, 2009

By A. E. Taylor, A. S. Judge, P. T. Lafleche

"Resource development in northern Canada has special requirements which derive from the unique environmental and eco-logical nature of the northern environment. In this paper several case histories in which the Permafrost Research Section of the Geological Survey of Canada (GSC) has participated are used to illustrate how geophysical methods may be used to address some of these considerations. Although some of these examples were developed while examining problems directly related to oil and gas development and transport in frontier regions, such or similar methods also have application to mining problems.IntroductionA critical parameter is the distribution and thickness of permafrost, which in northern Canada varies from being a few metres and discontinuous at the southern limit to thicknesses in excess of 700 m in the Arctic Islands'!'. Figure I is a schematic diagram of typical ground thermal conditions in a permafrost zone. The upper zone is defined by an active layer which undergoes a seasonal freeze/thaw cycle. In the simplest case, the ground remains permanently frozen below the active layer to the depth of the O°C isotherm, which is defined as the base of the permafrost. Water chemistry, pore structure and pore or grain size may cause the base of the frozen ground to be above the permafrost by up to 100 m(2). Ice can be found within the permafrost in the pores of solid rock or sediments, as massive ice within unconsolidated sediments or as ice lenses within fissures in a solid rock mass. The mining technique used in these conditions, whether open pit or underground, can differ considerably from that used in southern Canada. In the high Arctic, for instance, the dry drift method is feasible underground in the permanently frozen host rock. The frozen nature of the wall rocks can obviate water-related problems."

Jan 1, 1987

By David O. DeGagné

While mine backfill plants are becoming increasingly more automated and instrumented, especially with paste fill operations, underground backfill distribution systems have hardly changed over the years. While fill properties are appropriately measured in the preparation plants, as backfill enters the mine borehole, the technology for control, data gathering and reporting is somewhat lacking. Mines typically experience problems with borehole and pipeline plugging, pipeline bursting, bulkhead failure and exposed fill sloughing. With adequate instrumentation of the backfill system it is possible to obtain a complete, continuous and detailed picture of the entire filling operation from preparation to post-pour. Good data will, over time, provide the basis for needed improvements of backfill systems and will be essential to safer, more efficient and less costly fill practices. This paper will review the areas of the filling operations where monitoring would prove critical to eliminate failures such as pipelines, bulkheads, fill exposures, stope walls, etc. The types of monitoring systems currently available will be reviewed and potential areas for development will be highlighted.

May 1, 2001

By D. C. Treilhard

After a brief history of the mining and smelting operations of Kilembe Mines Limited, this paper outlines the smelter layout and describes . the. daily operations at the Jinja plant. Particular attention 1s paid to the details of the furnace and converter operation. A subsequent section of the paper deals with the significant developments in plant metallurgical practice, covering both smelting and converting.

Jan 1, 1966

By A. Sheikh, S. Hardcastle

"Various methods of leaching are being used by Denison Mines Ltd. Uranium Operations. This study was designed to investigate the flood leaching operation of two parallel inter-connected stopes contained by pressure bulkheads. The teaching muck piles, created from large scale uppers production blasts, are aerated by compressed air lines laid beneath the pile prior to blasting.A SFr, tracer gas, injection technique has been employed to determine the post-blast integrity of the single-ended air distribution system. SF6 was injected into the compressed air line feed to the stopes and collected at borehole exhausts from the stopes in grab-sampling bags. Analyses of the air samples were performed with a gas chromatograph.The system was designed to give a sufficiency of oxygen to sustain bacterial activities used to enhance the leaching recovery in the muck piles. The results obtained indicated that there is a minor anomaly in the distribution system that may not be critical to the operation. Compared to an idealized case, the over-all efficiency of aeration throughout the muck is estimated at over 85%."

Jan 1, 1988

By Donald Leroux, Ralph Dahlke, Dave Scott, Finch. James A., Cesar O. Gomez

"The efficiency of the flotation process depends on how effectively air is dispersed into small bubbles. Bubble surface area flux - the surface area of bubbles per unit time per unit cross-section area of a cell - is emerging as the parameter to characterize gas dispersion. One of the approaches proposed to measure bubble surface area flux in industrial cells is based on the measurement of two variables: gas velocity and gas holdup, using separate sensors. Plant testing of the gas velocity sensor gave evidence of a series of operational problems which may be necessary to correct before attempting to characterize gas dispersion. Problems such as uneven air distribution within a cell and along a bank, faulty air and slurry valves detected during attempts to redistribute air, and poor control of pulp level and gas flow became evident. Detection of these problems from gas velocity measurements is illustrated.INTRODUCTIONBubble surface area flux is considered a key variable in the optimization of flotation circuit performance (Gorain et al., 1997; 1998). The Mineral Processing Group at McGill University has devised and developed a method for estimating bubble surface area flux in industrial flotation cells (Finch et al., 1999). The method is based on measuring gas holdup and superficial gas velocity using two separate sensors and applying drift flux analysis to estimate bubble size (Dobby et al., 1988; Banisi and Finch, 1994). With bubble size and superficial gas velocity known bubble surface area flux can be calculated.This method was selected by Noranda to characterize gas dispersion in cells as part of a program to model and optimize flotation circuit performance. However, initial testing at Brunswick Mine with the gas velocity sensor provided some unexpected results indicating operational problems and equipment malfunctions that needed to be addressed before systematic measurement of gas dispersion could be initiated.The subject of this communication is to illustrate the detection of these problems from gas velocity measurements. The line 3 Zn Cleaner circuit comprising four stages of Denver DR cells was the main subject of analysis, including the effect of correcting these problems on the metallurgical performance of the Zn 3rd cleaner bank of ten DRl 00 cells."

Jan 1, 2001

By L. V. Kin, V. V. Lodeischikov, A. V. Byvaltsev, IRGIREDMET JSC, O. D. Khmelnitskaya, S. V. Petrov

"Irgiredmet Institute carried out the study on the development of gold recovery technology from refractory ore from a Russian deposit. The ore contained 1.1 g/t Au, 1.5% of pyrite and 2.4% of pyrrhotite. The recovery of gold achieved was 84.7% using gravity with generation of high grade recoverable gold concentrate and gravity middling. In the course of lime treatment, cyanidation of the middling followed by tailings detoxification the consumption of reagents was 13.0 kg/t CaO, 95 kg/t NaCN and 72 kg/t Ca(OCl)2 of the concentrate. This was capital intensive.In order to decrease the consumption of reagents, magnetic separation of the middling of the concentrates from gravity separation was added to this flow sheet. Pyrrotite recovered to magnetic fraction, which did not contain gold in accordance to this advanced flow sheet. The mass yield of pyrite goldbearing non-magnetic fraction decreased down to 1.5 times in relative to gravity middling. The slurry filtration prior to and after cyanidation allowed the organization of cyanide solution recycling.The results of pilot plant tests using the developed flow sheet showed that the content of pyrrhotite in the non-magnetic fraction decreased from 59.1% to 11.3%. The reagents consumption was 12 kg/t CaO, 3 kg/t NaCN and 16 kg/t Ca(OCl)2 of the pyrite concentrate. The total gold recovery using this flow sheet was 83.4%. Due to a decreased consumption of reagents, cost efficiency of the process was achieved. Based on the results of this research, a project design criteria was developed. A processing plant with the annual throughput of 2.6 million tonnes of ore is being designed."

Jan 1, 2016

By W. D. Breil, C. B. Ison

A collection of general performance data relating to the G.H.H. - Gutehoffnungshiitte multi-rope friction hoist will be discussed together with some aspects of the following: overspeed supervision by a pantam device as opposed to the lilly type of fly ball control, automatic control systems, multi-disc braking, generator and motor winding, constant temperature monitoring, the development of an automatic hoist-rope lubrication system, and the control of rope tensions by the installation of G.H.H. - Gutehoffnungshiitte hoist rope fine tensioning units.

Jan 1, 1972

By K. D. Peaslee

Slag splashing is an important development that has dramatically improved BOF vessel campaign life and reduced operating costs. This paper highlights research from physical modeling work using a 1/8-scale room temperature model BOF and slag characterization studies from several plants in North America and China. In the model studies, gas flow rate during blow and viscosity of the liquid were found to be two of the most important factors to changing the overall rate of liquid splashed onto the vessel sidewalls. When the flow rate was increased or viscosity decreased, the lower regions of the walls were splashed at a much greater rate. It was also shown that by changing the lance height, more liquid was deposited in the upper regions of the vessel at the expense of lower regions. Reducing the number of nozzles was found to be the most effective method of selectively coating a particular vertical section of the wall. Studies of BOF's using slag splashing in North America and China showed a difference in the melting characteristics of the final slag. Generally, slag splashing is successful when the melting point of the slag is 220-270°C below the tap temperature to maintain a balance between fluidity and refractoriness.

Jan 1, 2004

By Don Ritz

Smart leaders focus on safety even in tough times. Businesses that retreat into survival mode and ignore safety do so at their peril, risking loss of employee and stakeholder confidence and exposing themselves to financial and reputational loss they can ill afford. It?s a moment of truth when employees and stakeholders learn whether safety is truly your priority or just a convenient cliché for good times. Visionary leaders who build safety culture even in a downturn maintain people?s trust, prevent loss, and position the organization for enhanced success as times improve. Safety is the right business focus in good times and bad.

May 1, 2009

By Rees J. Llewellyn

Improved product development, assessment methods and evaluation studies of materials for oil sands applications have traditionally focused on low and high stress abrasion and slurry erosion resistance mechanisms, because they were considered to be the predominant wear modes prevailing in oil sands mining, transportation and bitumen recovery. More recently with the very successful introduction of oil sands hydraulic transportation systems, there has been increasing use of crusher systems in which materials of construction are also required to have good toughness and gouging abrasion properties to withstand impact and the severe indentation and ploughing forces that are involved. To assess material property requirements for mitigating this additional wear mechanism, jaw crusher gouging abrasion tests using a modified ASTM G81 procedure, have been carried out on a range of wear materials of interest for oil sands mining service. The method involves a comparison of the wear losses that occur for reference and selected test plates when a controlled amount of standard feed rock is comminuted in a laboratory jaw crusher. Among the classes of material evaluated have been Q&T plate steels, austenitic manganese steel, chromium and chromium molybdenum white irons as plain castings and in laminated forms and also chromium carbide and tungsten carbide overlaid wear plates.

May 1, 2004

By V. I. Lakshmanan

Recycling helps to save energy and is good for the environment. It is also important for preserving the limited natural resources. In addition, recycling creates economic benefits and frees up space at the landfill sites. Process Research Ortech Inc. (PRO) has conducted extensive testwork in the area of waste processing and recycling. A process was developed for the recovery of Zinc from galvanized steel by alkaline leaching followed by solvent extraction and electrowinning. Extensive testwork has been conducted at PRO to obtain a useful by-product from rice husk. Rice husk was combusted in a gas/solid reactor to obtain an environmentally acceptable amorphous silica ash suitable for use in high strength concrete. In another development, vanadium was recovered from fly ash by separating carbon first, followed by alkaline pressure leaching, solvent extraction and precipitation. PRO has also developed an environment friendly process for treatment of industrial wastewater for its reuse to obtain zero or minimal effluent discharge. In this paper, four case studies related to recycling of zinc scrap, controlled combustion of rice husk, processing of fly ash, and reuse of waste water will be discussed.

Jan 1, 2011

By A. B. Barlow, D. H. Pitcher

"The Geophysics/Geochemistry Section of the Ontario Geological Survey initiated an aerial geophysical survey in the James Bay Lowlands, Cretaceous Basin area, District of Cochrane, Ontario. The survey was contracted to Scintrex Limited and was carried out in 1978. Approximately 8000 line kilometres of airborne electromagnetic and magnetic data were recorded. The Tridem airborne electromagnetic system was employed, mounted in a twin-engined PB Y Canso aircraft. This specific Tridem system uses a vertical coaxial coil configuration and measures in-phase and quadrature components of the secondary field at 500, 2000 and 8000 Hz.The primary purpose of this survey was to map subsurface conductivities and, in particular, to search for lignite deposits. Physical property measurements show that electrical methods should detect differen ces in conductivity between the moderately conducting clay-lignite horizons and the less conducting clay, soil, muskeg and gravel horizons. A preliminary Tridem test survey, as well as surface DC resistivity soundings, confirmed this approach. The interpretation of the present survey data indicates that Tridem is a suitable electrical method to aid lignite exploration in the James Bay Lowlands."

Jan 1, 1980

By François Charette

High stress conditions in underground mines push the performance envelope of support systems to their limit. In weak rock masses these conditions lead to large deformation and breakdown of the rock material, while stress release events in hard rock mines can lead to sudden and usually violent rock and support failure. In typical support systems, a combination of different reinforcement and support mechanisms provide the required convergence control and retainment. These systems usually involve a multi-pass support installation. The advantages of a single pass support system are investigated and several bolting combinations are compared. Criteria for design are reviewed and new criteria are proposed to include cost and effectiveness in commonly used engineering approaches. Field observation and testing is used to illustrate the difference between the proposed approach and more conventional systems.

Nov 1, 2011

By N. Shi, T. G. Joseph

ABSTRACT A revised equilibrium approach to evaluate dipper-ground interactions during the dig cycle of ultra-class mining shovels operating in soft unblasted uniform ground conditions is presented. A review of previous approaches, leading to an outline of the modifications and ground condition considerations, is made in support of the reasoning and basis for the derivation presented. An analytical solution is provided to the scenario of a cable shovel dipper digging in soft ground material such as oil sands.

Jan 1, 2012

By Jeff R. Reinson

The Diavik Diamond Mine is producing diamonds from two orebodies, the A154 South and A154 North kimberlite pipes, discovered beneath the waters of Lac de Gras. Innovative dike technology with appropriate water collection and treatment systems allowed Diavik to start open pit mining of the ore bodies in 2002. To allow planning, engineering, and implementation of sufficient water handling infrastructure, reasonably accurate estimates of groundwater inflow quality and quantity over the life of mine are required. Prior to mining, a numerical model using the continuum approach was developed for regional and site wide water management. After approximately two years of mining, groundwater inflows to the pit were found to exceed those predicted by the base case hydrogeologic model. The most likely explanation was flow through Dewey?s Fault zone. As this fault was not explicitly accounted for in the model, a detailed hydrogeologic investigation was conducted to evaluate its geometry and hydraulic properties. A multi-disciplined approach was used and involved core logging, fluid logging, geophysical logging, packer testing, a pumping test, and water quality sample collection. The results of the field investigation were used to update the conceptual and numerical models and to develop a Discrete Fracture Network (DFN) model to address small scale problems such as flow into future underground drifts. The updated numerical hydrogeologic models predict that up to 70 per cent of the groundwater inflow to the A154 N/S open pit is through the relatively narrow fractured rock zone associated with Dewey?s Fault. Consistent with the continuum model, the DFN model predicts that inflow to a drift excavated in Dewey?s Fault will be approximately 10 times the inflow to a drift excavated in competent rock. The DFN model provides a better understanding of the distribution of these inflows on a local scale over the length of the drift.

May 1, 2006

By J. T. Fyles, C. G. Hewlett

"THE REEVES MACDONALD mine is in the Sa Imo-Pend d'Oreille mining area of southeastern British Columbia. It is on the Nelway-Waneta road 4 miles west of the border-crossing point of Nelway. The Reeves orebody from which all production has come is one of several mineralized zones in easterly-striking limestones occurring between the Pend d'Oreille and the lower part of Salmo River.The property was originally located as two groups of claims by R. M, Reeves and J. H. McDonald. The two groups were consolidated in 1925. and extensive development work was done from then until 1930 and again in 1937, but no ore was shipped. The mine was reopened in 1947 and, between 1949 and 1953, 1,057,804 tons of ore was mined. Concentrates recovered contained 85,626 ounces of silver, 19,394,092 pounds of lead, 72,076,495 pounds of zinc, and 455,051 pounds of cadmium. Low metal prices forced the mine to close in 1953, but operations were resumed in November, 1955.The orebodies at the Reeves MacDonald mine are steeply plunging lead and zinc sulphide replacement deposits in a banded limestone named the Reeves limestone. The orebodies contain pyrite, honey-coloured sphalerite, and galena, and are surrounded by a dolomitized zone. In the Reeves orebody, where the relationships are known, the dolomite has the same general shape as the orebody. Four zones of sulphides are known on the property (see Figure 1). Three of these, the Reeves, B. L., and O'Donnell, are believed to be faulted segments of one mineralized zone. The fourth, the Point ore zone, exposed on the north bank of the Pend d'Oreille River, is not developed and its structural position is not known, but it appears to be a separate deposit."

Jan 1, 1949

By W. R. Dodge

THE growth and development of the assay department of the Hollinger Consolidated Gold Mines, Limited, is a similar story to that of the mine itself. As the mine developed and enlarged, so also increased the demands upon this department, necessitating an increase of capacity for fire assaying and a widening of the scope of work to include chemical analysis, metallurgical tests, research, and screen analysis. The yearly total of determinations, taking an average for the past six years, is approximately 350,000. The major portion of this figure represents fire assaying for gold and silver, being approximately 950 fire assays per day. The assay department occupies the ground floor of the administration building and covers approximately 4,000 square feet of floor space. Ready access is had by motor truck and electric railway for the delivery of samples and the removal of crushed rock and rubbish. The combined weight of all sample rejects amounts to about 5,000 lb. per day, which is sent to the mill bins. There are six departments, each occupying a separate room-grinder room, fluxing room, furnace room, parting room, weighing room, and flux-mixing and storage room.

Jan 1, 1931