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By John G. Payne

The Pebble deposit contains three contiguous zones. In the Pebble West zone, granodiorite stocks intrude gently warped volcanosedimentary rocks that had been intruded by diorite sills and two felsic intrusion breccias. In the Central zone, volcanosedimentary rocks are cut by diorite and granodiorite sills; the latter are genetically associated with the granodiorite stocks. In these zones, widespread potassic alteration consists of brown biotite and K-feldspar, with abundant quartz-carbonate-sulphide vein stockworks. Chalcopyrite/pyrite ratios range from 2/1 to 1/20. Diorite hosts the highest-grade mineralization, with much of it being disseminated. Patchy, later phyllic alteration is moderate and commonly depleted in copper. The Pebble East zone occupies a granodiorite stock and intruded host rocks below an eastwardly thickening wedge of barren Tertiary volcanic and sedimentary rocks up to 600 m thick. Brown biotite alteration and copper mineralization are strong, with chalcopyrite/pyrite ratios commonly over 1/1. The zone extends to a depth of at least 1200 m below surface; some drill holes bottomed in strong mineralization. Later, weak to moderate sericitic alteration removed some chalcopyrite and locally remobilized gold. The Pebble deposit has a Measured/Indicated resource of 3 billion tonnes grading 0.28% Cu, 0.32 g/t Au and 0.015% Mo (= 0.5% copper-equivalent) and an Inferred resource of 1.13 billion tonnes grading 0.30 g/t Au, 0.27% Cu and 0.015% Mo (0.55% copper-equivalent). The Pebble East zone has an Inferred resource of 2.13 billion tonnes grading 0.55% Cu, 0.34 g/t Au, and 0.037% Mo (0.97% copper-equivalent). The Pebble East zone is open to the east and to a lesser extent to the north, south, and to depth.

May 1, 2006

By Jessica Egan, Daniel Hodouin, Mohammed Reza Khalezi, Steve Bellec, Claude Bazin, Carl Duchesne

"A model for gold leaching was developed and implemented into a simulator. The simulator uses a description of the ore that is based on the mineral composition and precious metal content. The model accounts for the distribution of minerals and precious metals through the size intervals. An ore texture model based on precious metals and minerals grain sizes within the ore is used to predict the exposed surface of the species in the various size intervals. A model is proposed to predict the rate of dissolution of any species dissolution using the exposed surface, particle size, cyanide and oxygen concentrations, temperature, pH and agitation. The flow of slurry through a leaching tank is modelled using a parallel arrangement of perfect mixers to simulate a bypass and a Cholette-Cloutier mixer model. The simulator can be used for circuit optimization but was developed to provide an environment for learning the basic concepts of process analysis methods. Examples are given to illustrate the application of the simulator for planning tracer tests and sampling campaigns.INTRODUCTIONThe constant pressure to improve the operation of processes that are already close to optimum imposes to plant engineers to be aware of the available process analysis tools and to be able to use them to assess process operation and make a diagnosis to possible problems. Some of these tools are:•,Sampling the streams of a process;•,Data reconciliation;•,Analysis of mixing in reactors;•,Estimation of rate parameters;•,Optimal tuning and flow sheet modification;•,Automatic control and real time optimization.Although some of these tools are part of the curriculum of many university engineering programs, the students are not exposed to actual process analysis problems. In addition the complexity of the ore dressing processes compounded with unavoidable measurement errors and plant disturbances can discourage many motivated engineers. These factors often lead to an incomplete valorization of the collected data and a poor return on the investment associated with the sampling, testing and analysis of the samples.Simulators are readily available for process optimization (Yalcin and Shang, 2006) by allowing:•,The simulation of various flow sheet configurations;•,The simulation of a change of operating conditions;•,The simulation of various control strategies;•,The training of plant operators.However few simulators have been developed with the objective of providing an environment for training plant engineers and technicians to the use of tools for process analysis and optimisation."

Jan 1, 2008

By Steve Wilkinson

"""Techniques for coarse-particle beneficiation of some gold ores and methods for determining potential for sorting any gold ore deposit.""With the advent of high speed computers, laser technology end different types of electronic sensing devices, ore sorting machinery has been developed, capable of handling significant tonnage rates while maintaining high level efficiency. Gold ores may be amenable to coarse-particle beneficiation where there exist measurable criteria upon which there can be recognition of auriferous versus barren lumps in the run of mine. Three types of criteria are suitable for sorting and are:i) Photometric - optical variance between ore and waste such as vein ores hosted by barren country rock;ii) Conductivity/Magnetic - based upon the metallic mineral content of ore end waste, and its association with Au, such as found in sulphide/arsenide Au ores,iii) Radtometric - detection of natural gamma activity occurring with uranium-bearirig gold ores.The method for determining the sortability of an ore depositconsists of, at least, three stages:i) Initial stage identification of ore and waste types,mineralogical/petrographical associations,amount of dilution in P.O.M.establishment of any sorting criteria]"

Jan 1, 1985

By Allen Chung, John Twomey, Christopher J. Greet

"It is widely accepted that the type of grinding media has an impact on the grinding chemistry and subsequent flotation behaviour of the sulphide minerals being separated. There are countless laboratory investigations demonstrating that inert grinding media produces more oxidising pulp potentials, reduced levels of grinding media corrosion products and superior concentrate grades and valuable metal recoveries. However, taking these results to industrial scale has proven difficult.Work conducted at the Ernest Henry Mine, in north western Queensland, Australia, at laboratory and pilot plant scale clearly indicated that using a high chrome grinding media resulted in significant improvements in both copper and gold recoveries. However, advancing this work to plant trial represented considerable financial and technical risk to the mine.This paper provides details of the protocol developed and used during the high chrome grinding media plant trial. It describes the test regime employed to measure changes in pulp chemistry, and the statistical methodology utilised to interpret the results. The work also highlighted the need for close cooperation between the metallurgists on site and the researchers conducting the trial.To date, the trial has produced excellent results: indicating that the copper recovery has improved by about 2 percent. The successful application of high chrome grinding media to the Ernest Henry ore has increased metal value by $18.7 million USD per annum based on current spot price for copper.INTRODUCTIONTheoryThe application of electrochemically inert grinding media to mineral systems has been extensively studied (Table 1). Broadly, these studies indicate that most sulphide minerals are more noble than the grinding media used during comminution. Therefore, the sulphide minerals are cathodic with respect to the forged steel grinding media, and the following reactions apply:"

Jan 1, 2011

By D. M. Doyle, P. J. Hannon

"The Canada/Nova Scotia Mineral Development Agreement (M.D.A.) is a subsidiary of a five-year Economic and Regional Development Agreement, signed on June 11, 1984. The objectives of the M.D.A. are to strengthen and diversify the Nova Scotian mineral industry and to coordinate federal and provincial policies and programs. The agreement outlines the activities and responsibilities of each government, including the division of the cost (60:40, federal: provincial) between governments. The agreement established a framework for joint planning to avoid overlap or duplication of programs.The M.D.A. programs are broadly divided into five sectors (Table 1 and Fig. 1): Geoscience, Minerals Technology, Development, Firm Specific and Public Information. Each sector is administered by a subcommittee composed of one federal member and one provincial member. The subcommittees report to a Management Committee. The Canada/Nova Scotia Mineral Development Agreement (M.D.A.) Management Committee is made up of Dr. Jack Reeves from EMR and Dr. Richard Potter from the NSDME.The Geoscience subcommittee, co-chaired by Peter Giles (NSDME) and William Poole (EMR), manages the regional geologic, geochemical and geophysical studies in the province. Included in this sector are studies into mineral deposits and the basic geological relationships between mineral deposits.The Mineral Technology sector is co-chaired by the authors, Don Doyle (CANMET) and Pat Hannon (NSDME). This sector of the M.D.A. conducts studies into mineral processing, sampling, deposit byproduct commodities and project feasibility analysis."

Jan 1, 1987

By J. M. Simard, S. Morissette, P. Coursol, P. Mackey

A new, powerful model is presented that focuses on plant logistics and scheduling aspects of the smelting, converting, fire refining and casting operations at the Horne smelter. This plant complex is the largest custom copper smelter in North America. It handles a wide range of feeds and utilizes a number of proprietary continuous and batch technologies that require good scheduling in order to maximize plant capacity and efficiency. The present model was developed by Xstrata Process Support, in collaboration with the Horne smelter, and uses the Arena® software to evaluate the impact of a number of plant variables on the annual copper capacity of the plant. Model development was carried out by Xstrata Process Support, in collaboration with the Horne smelter, through the effective combination of process chemistry knowledge and detailed knowledge of the plant operation (including all material flows and transfers, as well as information such as operating on-line times, plant stoppages and also scheduled and unscheduled maintenance activities). A number of case studies were then examined, including the impact of anode furnace and casting cycle times on annual copper capacity and the impact of a one-crane mode of operation in the converter aisle, which normally operates with two cranes in service. The model predictions were found to match actual plant results very well. The present modelling of plant logistics and the scheduling aspects were found to add important dimensions at the plant with regard to projections of the real-life plant capacity. As demonstrated in the present case, this type of model and application can have a significant impact on optimizing operations at a given plant. This impact is particularly important in the current market environment, where emphasis is on maximizing plant output and lowering costs. These models can help yield the easily obtained gains that are clearly desirable in these times. Xstrata Process Support has developed Arena models for other operations and is available to explore new applications for a win-win situation at other plants, including mines and concentrator operations.

Jan 1, 2009

By S. Klingmann, G. Blackwell

"Terrestrial photogrammetry has been used for many years to build three-dimensional pictures for analytical purposes. Photographs can include images from open pit mine walls, ground topography, mine buildings infrastructure or accident scenes. Analysis and co-ordinate estimation in early photogrammetric systems demanded the use of specialized and costly optical-mechanical stereocomparators. Few of these instruments could be interfaced with computers to provide databases, and all required trained personnel with good perspective vision to collect data.Digital photogrammetric software has replaced these older systems, and the digital video plotter (DVP) is a simple computerized system utilizing readily available PCs to quickly produce a stereoscopic model of any scene where an area of overlap exists in photographs taken from two different locations. Specialized cameras providing reference marks or grids on the photographs are still necessary for detailed analysis in three dimensions.This paper describes the application of DVP to the three-dimensional analysis of strike, dip and location of dominant fracture planes visible on an open pit wall slope, and the intersection of planar features which might reduce wall stability. Where reference survey points cannot be provided because access by personnel to the photographic scene is impossible for safety reasons, normal case terrestrial photogrammetry can provide the necessary control points for more complex aerial photogrammetry geometries.DVP recreates the geometry existing at the moment photographs are taken, providing the user with the ability to safely recreate, compare and analyze the structures determining the stability of open pit wall slopes."

Jan 1, 2003

By William Pitman

Ground instability and subsequent rock falls are a major concern in underground mines. As a result, several mining companies are conducting risk assessments of the ground support installed in their mines. Risk assessment is now commonly used to provide mine operators with a systematic process to assess the strategic risks that could lead to injury to personnel or loss of production, and evaluate possible risk control measures. Risk assessments can be carried out to identify major hazards, assess the likelihood of occurrence and consequences of each hazard and estimate the level of risk. This process allows assessment of possible remediation actions to minimize the risk and likelihood of occurrence or mitigation of the consequences to a level that is reasonable and practical. This paper presents two practical mine applications of qualitative risk assessment of ground support to highlight the benefits of this process. Yearly or bi-yearly risk assessment of mine excavations can assist mine operators in prioritizing resources and areas that require support remediation. In addition, it provides a mechanism for proactive response to reduce potential risks associated with personnel safety, equipment safety and environmental impact. It also provides a baseline against which changes in ground condition can be compared and quantified.

May 1, 2004

By Karla Kaboth, Brad Garraway

"The surface of many concentrate thickeners has traditionally looked like that of a flotation cell. Over the last three years Normandy Golden Grove Concentrator, in partnership with Outokumpu Technology have developed and implemented an innovative breakthrough deaeration technology to address this problem.When installed in the thickener feedline, the system successfully detached air bubbles adhering to the solid particles and removed air bubbles from the feed stream, subsequently presenting a fully deaerated feed to the thickener feedwell.Tests to date have shown an 80% reduction in overflow solids. As a result, costs associated with concentrate loss and measures to recover concentrate that settles in process tanks and ponds have been minimized.MOTIVATIONIt is recognised in mineral processing operations that the entrainment of finely divided air in thickener feeds can cause significant problems in the operation of a thickener. This is particularly the case with thickening of flotation concentrates, in which air bubbles are strongly attached to the mineral particles and are difficult to remove. Such particles attached to fine air bubbles rise to the thickener surface, and hence over the weir and into the thickener overflow. High solids carryover can lead to a direct loss of mineral product, and if the product settles in process water tanks and ponds, the recovery of this product by means of intermittent dredging operations is usually expensive and inconvenient.Many concentrate thickeners are fitted with devices which attempt to alleviate this problem. Froth rings or baffles, skimmers and froth sprays, all play a part in reducing the amount of solids carried over into the overflow. However, many froths are very stable and persist despite these measures. In the worst cases, a thick froth layer forms which builds up to a depth greater than the froth ring, and hence may overflow or pass beneath the ring . Any concentrate that finds its way past the froth ring can also cause blockage of the overflow weir and launder, and has the potential to upset clarification performance by cutting off sections of the overflow handling system. The formation of a froth layer on the thickener also makes it more difficult for the operator to monitor the clarification performance."

Jan 1, 2001

The Stability Graph Method is widely used in Canadian underground hard rock mines for open stope support design and is frequently used in the mine planning phase to assess the viability of stope geometries and to determine maximum permissible spans. The Method is well accepted due to its simplicity and suitability to a wide range of mining methods requiring the use of sublevels to access and extract the mining blocks. While this Method is reliable in situations where the maximum induced tangential stress creates adequate compressive stress keeping the face in a state of confinement, the Method fails to reflect the effect of low confinement caused by lower compressive stresses and instances where tensile stresses are developed. In this paper, a new Rock Stress Factor, A?, an update to the original Rock Stress Factor, A, is proposed, which will reflect the impact of low confinement or overstress regime on critical face stability. Two case studies, based on two Canadian operating gold mine shows that using the new Rock Stress Factor A? to predict the stability of stope hanging-wall and footwall gives better agreement with the CMS survey results, compared with the prediction using the original rock stress factor.

May 1, 2011

By J. R. Goode

"The Las Cristinas deposit contains about 10.2 million ounces of gold at a grade of 1.3 g/t. The deposit comprises a layer of fully oxidized saprolite (SAPO), a layer of sulphide-enriched saprolite (SAPS), carbonate leached bedrock (CLB) and carbonate stable or un-leached bedrock (CSB). Gold occurs at about the same level in all lithological groups. The bedrock units contain minor amounts of copper (about 0.1%) as chalcopyrite, while SAPO contains virtually no copper it having been leached and deposited in the SAPS zone.A previous owner started investigation of the Las Cristinas deposit in Venezuela in 1991. Over the next seven years, 1174 holes with a total length of 159 km were drilled, extensive metallurgical testwork, including pilot plant operations, were conducted and feasibility studies were completed. Construction was started in 1997 and again in 1999 but was suspended.Crystallex has been producing gold in Venezuela since the early 1990’s. In 1997, Crystallex acquired Inversora Mael which had held two of the claims to the Las Cristinas concessions since 1986. In September 2002, Crystallex entered into a definitive agreement with the Corporación Venezolana de Guayana, (CVG), to develop the Las Cristinas deposit.An extensive program of studies and testwork was started in early 2003 to determine an optimum development plan for Las Cristinas. Mine Development Associates, SNC–Lavalin Engineers and Constructors, SGS Lakefield Research Limited, J.R. Goode and Associates, and Professor A. Laplante at McGill University acted as the main contractors.Because of the potential value of by-product copper, earlier flowsheets used carbon-in-leach for SAPO, but processed all other ore types by flotation to produce a gold-copper concentrate with cyanide leaching of cleaner tailings to maximize gold recovery. Cyanide recovery was necessitated by the high copper content of the leach feed. Initial studies of available data by Crystallex revealed that direct leaching of all ore types would provide about 11% more gold recovery than the previously selected flotation route with reduced capital and operating costs.Bench and pilot scale studies have confirmed that a SAG-ball mill-gravity-CIL route is very effective for all ore types and will give about 89% gold recovery. This paper describes the recent testwork, discusses the proposed plant design, and presents economic data."

Jan 1, 2004

By Rudy Tenbergen, Dick Farmery, Jim Naylor

"Paste backfill has replaced cemented rock fill as one of the components to improve ground · control and mine safety at the Macassa Operation of Kinross Gold Corporation in Kirkland Lake, Ontario. It is the first operation to utilize "" flash thickening ""of very fine gold tailings to a paste consistency in the ""Paste Production and Storage Mechanism"", a joint technical development of Inco and GL&V. The tailings paste is mixed with alluvial sand to produce an engineered quality paste backfill. The development leading up to the decision to proceed with this novel technology is discussed, as well as commissioning of the backfill operation.IntroductionThe occurrence of a major rockburst on November 23, 1993 prompted a review of mining and backfill procedures at the Macassa No 3 shaft . This shaft is some 7238 ft deep and lies in a mining belt that is prone to seismic events. The recommendations were to change the mining from underhand cut and fill to mechanized long hole stopping and to look at alternatives to the rockfill backfill system in place. The Macassa cemented rock backfill operation, while producing the desired fill stiffness had drawbacks as compared to paste fill. With paste fill, placement rates are faster, more openings can be filled, it is less expensive and less prone to the occurrences of compensable incidents.Macassa mining personnel visited the Sudbury operations of Inco in 1993, where development on paste backfill was in progress. As some of the R&D was taking place with funding from the Premier's Council Technology Fund of the Ministry of Trade and Technology of the Province of Ontario , Inco personnel at that time did some feasibility and conceptual consulting on the use of paste fill for the industry. Inco had developed the use of alluvial sand paste fill, an engineered blend of alluvial sand and tailings fines and was doing development work to eliminate the ""conventional"" way of producing paste from mill tailing by thickening and filtration. This latter development work was taking place with GL&V Ontario. That work led to the filing of a joint Inca/ GL&V patent application for the PPSM, the Paste Production and Storage Mechanism with all marketing rights being held by GL&V."

Jan 1, 1997

Experimental Mine, Val d'Or, Quebec, Experiments on the ignition of sulphide dust clouds by explosives have been conducted in a 1 m3 explosion chamber. The explosives tested are ANFO, emulsion, aluminized emulsion and Detasheet. By controlling the composition of the ANFO and the emulsion explosive the oxygen balance could be changed in order to identify the dominant factors in the ignition of sulphide dust clouds by explosives. Experimental results, combined with theoretical calculations, show that the temperature of the detonation products is the most important parameter in the ignition of the dust cloud while the combustible detonation products are of secondary importance in the case of non-aluminized mining explosives. In the case of aluminized explosives and explosives having very negative oxygen balance the ignition of the dust cloud is assisted by the large amount of combustible detonation products.

Jan 1, 1993

By R. Jolicoeur, J. F. Jackson, M. A. Green

"The design, construction and commissioning of Kiena Gold Mines Limited's new mill was completed in 15 months ending in September 1984. Rated at 1250 tonnes per day the mill incorporates the latest innovative technology such as semi-autogenous grinding, carbon in pulp, pressure stripping and induction furnace refining. The mill is housed in a pre-engineered building with the leach tanks and thickeners located outdoors in spite of the intense winter cold. 1.0 INTRODUCTION AND HISTORYThe operations or Kiena Gold Mines Limited are located in Dubw1sson Township, approximately 10 Km west of Val d'Or, in the Abitibi region northwestern Quebec. Comprised of 59 mining claims covering 1214 hectares, a large portion of the mining property is overlain by the waters of Lac de Montigny. Sometime between 1911 and 1914 Barney Parker discovered gold in a shear zone on an island in Lac de Montigny that now bears his name. The first shaft the Parker Shaft, was sunk in 1936 from the island to a depth of 136 meters but owing to the known veins being of limited extent and the onset of the Second World War operations were terminated in 1940. In the early l960 1 s exploration drilling indicated an orebody of 4,500.000 tonnes at 6.3 grams of gold per tonne. A causeway was built to link the island to the mainland in 1963 and a new 3 compartment shaft was sunk to 403 metres. The orebody was further delineated and the ground conditions within the orebody and surrounds were evaluated.At the end of 1965 the property was placed on a care and maintenance basis as a mining operation would be marginal with gold selling at $35 per ounce."

Jan 1, 1986

By H. D. Stolovitch, M. L. Lavallée

"An engineering system used to analyze and improve the performance of industrial grinding circuits has been adapted into a training program. The systematic approach to the design of training was applied in order to:Determine if training was an appropriate and effective tool for the transfer of this new technology;Define the technical content of the program;Establish program specifications based on learner and context characteristics;Design and test prototypes of the instructional modules; and,Establish a strategy for plant implementation and maintenance of the training program.This paper thus describes how a engineering system is transferred to the workplace through the use of designed instruction.INTRODUCTIONTraining can change human performance in a permanent way. It can improve productivity for the overall benefit of an operation. Organizations can therefore use training as a mean to achieve their specific goals. Training is not the solution to every performance problem. However, in many cases, it can be a very effective way to attain desired performance.The benefits of training are often difficult to assess. However, to remain competitive, organizations must introduce new products and innovative technologies. Often, they can do both most effectively through suitable training interventions.In order for the effort and investment of training to provide optimal results, two points of view should be adopted.• An overall view of the system in which training is to be applied.• A systematic approach to the design of training (Stolovitch and Keeps, 1989)."

Jan 1, 1992

By Benjamin H. Clark

"For over 50 years, Derrick Corporation has been renowned for its innovative and durable fine screening equipment and screen surface technology. Derrick’s latest innovation, the patented Stack Sizer, offers mineral processors both high tonnage capacity and high separation efficiency on an extremely small footprint.The Stack Sizer is suitable for separations from 6.3 mm down to 75 microns (200 mesh). The Stack Sizer, coupled with Derrick’s patented urethane screen surface technology, offers an extremely economical alternative to hydraulic classifiers, hydrocyclones, and less efficient low volume wet screening systems. Stack Sizers have been used in feed preparation for flotation, spirals, and a variety of jigs. Mineral processors wishing to reduce grinding circuit circulating loads and generation of slimes due to over grinding, thereby enhancing the efficiency of flotation and gravity circuits, now have another technology at their disposal to perform this critical sizing and grade control function.Over 200 Stack Sizers have been installed in numerous mineral processing applications worldwide attesting to the rapid acceptance of this technology. Stack Sizers are currently screening ferrous and non-ferrous metal ores, mineral sands, silica sand, kaolin clay, feldspar, garnet, phosphate, aluminum dross, potash, coal, tantalum, spodumene, niobium, and other rare earth mineral ores.INTRODUCTIONDerrick engineers have long understood and demonstrated the importance of screen width in coupling both high capacity and high separation efficiency for fine wet sizing applications. As opposed to fine dry sizing, where the length of the screening machine is critical for high separation efficiency, introducing slurry feed to screens in a thin and even layer at minimal velocities across wider screen surfaces allows for high capacities and efficiencies, with maximum screen cloth life. This is due primarily to the combination of free liquid and high frequency vibration of the Derrick motors, which allow fine undersize material to pass through the screen apertures. Lacking either of these factors would be extremely detrimental to the screening process. Without the high frequency vibration of the motor, the screen is essentially a low efficiency sieve bend. Without the free liquid to carry fines through the screen openings, the screen is for all intents and purposes a glorified conveyor or dewatering unit, as little or no sizing takes place once the screen is devoid of free liquid. For optimal screening results, Derrick recommends feeding slurry to a screen at approximately 20% solids by volume. Figure 1 shows the Stack Sizer design concept. Note that a single feed point is used to evenly distribute the flow to the five separate feed points."

Jan 1, 2007

By John H. Fowler

"Most of the aggregate used in Nova Scotia is produced from numerous glaciofluvial and ice-contact deposits scattered throughout the province. Production from bedrock sources is increasing, with most of the coarse aggregate used in the Halifax-Dartmouth area coming from quarries operating within the metro area.A recently completed provincial sand and gravel inventory mapping program has identified some ""resource-poor"" areas where comprehensive aggregate evaluation programs are underway. Although some areas of the province are experiencing aggregate supply problems, large volumes are exported to markets as far away as Bermuda.IntroductionThe Nova Scotia Department of Mines and Energy has been involved with aggregate resource studies for several years, although sand, gravel and crushed stone are not designated as minerals under the Mineral Resources Act of Nova Scotia. Our role has been to provide the aggregate industry with resource data as well as provide similar information to governmental agencies involved with municipal planning, water resource studies and environmental protection regulations. Several private consulting firms use the information in many of their site development studies.We became involved with aggregates in a rather roundabout way. Several years ago, an outcry from inhabitants of a small coastal community over the removal of sand and gravel from a local beach moved the provincial Department of Lands and Forests to take action to protect provincial beaches. We were asked by the Department to provide information and to suggest alternative sources here operators extracting sand and gravel from beaches could relocate. This request initiated an aggregate inventory survey in southeastern Cape Breton, which was later extended to cover the entire province. The initial provincial sand z and gravel inventory survey provided a series of 1:50,000 maps showing the distribution of sand and gravel deposits in the province."

Jan 1, 1982

By C. O. Aksoy

There is a long history of coal production in Turkey with electric energy generated from power plants since the 1950s. However, the cost of power generation is high. Therefore, it has become necessary to find a means of decreasing production costs to become more competitive in a global market. This paper attempts to economically minimize the overall operating costs of a dragline-shovel-truck system applied at an open pit mine that has fed the Yatagan power plant since 1979, lowering the lignite production cost, and indirectly, the overall electricity generation unit cost. Systems currently in place, as a result of former optimization studies, are time-consuming and expensive to re-implement to comply with today’s very different geometric and economic conditions affecting mining operations. In such cases, rather than re-optimization, it is more viable to identify the parameters that affect the minimum unit cost, via a cost minimization study, allowing present mine equipment to be utilized more efficiently. Unit cost minimization analyses are subject to the capacity of the pool of mining equipment available, combined with the mining block geometry from pre-stripping onwards. In this overall unit cost minimization study, P&H shovels and CAT 777 trucks with capacities of 15 yd3 and 77 tons, respectively, were used in truck-shovel pre-stripping operations. A 65 yd3 Marion 8050 dragline was used to expose the overburden immediately over the coal seam. Pre-stripping bench heights varied from 8 m to 20 m and dragline bench heights from 20 m and 25 m were evaluated to minimize the unit cost of field operations. Total overburden extended to a depth of 60 m (35 m to 40 m for pre-stripping). Minimization analyses performed on the pre-stripping truck-shovel operation, prior to dragline operations, determined that the shovel bench height should be 15 m requiring a dragline bench height of 25 m.

Jan 1, 2005

By Patrick F. R. Murphy

The mechanization of platinum group metal (PGM) underground reef mining in South Africa has posed a challenge to mining engineers for several decades. This is primarily due to the shallow dip angles and narrow thickness (<1.1m) of the tabular orebodies mined, and the issues faced in developing reliable drilling, bolting and loading machines suitable for such hard-rock mining applications. Presently, mining is typically conducted using hand drills and scraper shovels. These methods, however, are intensive in terms of manual labor, and limited in terms of productivity, and improved methods are desired. This paper will review the technical features of a 4 tonne, low-profile, LHD for narrow-reef PGM mining, developed by EJC Loaders Division.

May 1, 2003

By A. D. Thomas, V. N. Rampton, S. Paradis, C. F. Gleeson

"A shallow till sampling program was completed on a 1 km grid over the St . George Batholith in southern New Brunswick. The ""B"" soil horizon was analyzed for Cu, Pb, Zn, Ag, Co, Mo, U and Sb and the heavy minerals from the ""C"" soil horizon were analyzed for W, Sn and A u. The results delineated four of five recorded W occurrences, three of four recorded Mo occurrences, all recorded Cu occurrences and one recorded Au occurrence. The results indicate that shallow till sampling in conjunction with bedrock and Quaternary mapping can inexpensively define exploration targets in terrain similar to that underlain by the St. George Batholith.A similar program was carried out in eastern Ontario involving the analysis of four separates from the till, the ""8"" soil horizon, the -50 mesh fraction, the -250 mesh and the heavy mineral fraction of the ""C"" soil horizon and humus. Also sampling was carried out near known gold occurrences at closer spacings. Regionally, anomalous results from all sample media clearly defined a large auriferous shear zone and associated splays. Over one known showing all media clearly defined the showing and a secondary zone. On the regional scale the heavy mineral fraction gave the best anomaly definition and contrast, but the -250 mesh fraction was found to be the most cost effective for defining exploration targets. For detailed surveys, humus was found to be cost-effective."

Jan 1, 1986