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By B. W. Madsen

To help maintain an adequate supply of minerals to meet national economic and strategic needs, the Bureau of Mines developed a mathematical model that describes acidic ferric sulfate leaching of copper from sulfide ores. The leaching model can aid in maximizing minerals and metals recovery from primary sources by giving operators and management a better understanding of the copper leaching process. This will aid in improving dump leaching operations. The model is based on a steady-state approximation of the continuity equation for diffusion of ferric ions in the rock pores and the intrinsic leaching kinetics of the various sulfide mineral particles. Ore characteristics included in the model were ore particle-size distribution, particle shape, grade, mineral content, mineral particle size, porosity, and tortuosity. The continuity equation was used with ferric ion concentration gradients and a fixed value for the diffusion coefficient. Except for effective diffusivity, each of these factors was either measured experimentally or estimated from theoretical considerations. The effective diffusivities were determined by fitting calculated leaching curves with experimental leaching data. Vertical variations in leach solution composition and temperature within a dump are not considered in this model. The model accurately predicted copper extractions for several large-scale tests during nearly 500 days of leaching.

Jan 1, 1981

By C. Crussard, R. Tamhankar

It is the policy of The Metallurgical Society to provide, in the TRANSACTIONS OF THE METALLURGICAL SOCIETY OF AIME, a prompt and accurate medium for publication of reports of significant new research in both the scientific and engineering aspects of metallurgy. Papers submitted to the Society are judged by competent reviewers accord-ing to established criteria for technical merit, accuracy, originality, and presentation. STAFF: Editor, Gerhurd Derge Carnegie Institute of Technology Schenley Park Pittsburgh 13, Pa. Editorial Assistant, M. A. Redmerski Staff Coordinator, James J. Burke THE METALLURGICAL SOCIETY: W. R. Hibbard, Jr., President; J. C. Kinnear, Jr., Past-President; John Chiprnan, Vice President; T. D. Jones, Treasurer; R. W. Shearman, Secretary. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: A. W. Thornton, Chairman; Dennis Carney, John Chip-man, J. C. Fulton, J. H. Hollomon, H. H. Kellogg, A. E. Lee, R. Maddin, J. D. Sullivan, and D. Swan. Review and selection of manuscripts is under the supervision of the following Publications Committees: Extractive Metallurgy Division: T. B. King, Chairman; S. J. Dickenson, R. P. Hermsdorf, R. Schuhmann, Jr., and P. T. Stroup. Institute of Metals Division: Robert Maddin, Chairman, F. Lincoln Vogel, Jr., Vice-chairman, W. A. Backofen, R. W. Balluffi, J. H. Bechtold, M. B. Bever, R. S. Busk, C. G. Goetzel, Paul Gordon, C. D. Graham, .Jr., Robert F. Hehemonn, R. I. Jaffee, F. E. Jaumot, Jr., Irving R. Kramer, A. J. Lena, Harold Margolin, C. J. McHorgue, Russell A. Meussner, J. B. Newkirk, H. W. Paxton, G. E. Pellissier, I. S. Servi, Alan U. Seybolt, A. J. Shaler, and Jack Washburn. Iron and Steel Division: J. C. Fulton, Chairman; T. B. King, F. C. Langenberg, W. 0. Philbrook, and T. 0. Winkler. Published bimonthly by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc., 29 West 39th Street, New York 18, N. Y. Telephone: PEnnsylvania 6-9220. Subscription $20 per year for non-AIME members in United States and North, South, and Central America; $25, foreign; $5 for AIME members. Single copies, $4.00, single copies foreign, $5.00. The AIME is not responsible for any statement made or opinion expressed in its publications . . . Copyright 1958 by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. . . . Registered cable address, AIME New York ... Indexed in Engineering Index, Industrial Arts Index, and Chemical Abstracts... Second class postage paid at New Yark, N. Y., and Ann Arbor, Mich. Volume 212, Number 6.

Jan 1, 1959

By A. T. Sutaone

"In the Dongri Buzurg Manganese Mine of M/s Manganese Ore (India) Ltd., high grade lumpy manganese ore required for iron and steel industries is produced through multi-stage crushing and screening. This has resulted in accumulation of 50,000 tonnes of low grade fines over the years. This production of such fines is still going on. The fines create environmental problems, like air and water pollution and siltation in adjoining fields. Besides containing lot of manganese values, they occupy large space which is very scare in mining area.The Indian Bureau of Mines under one of its statutory functions has suggested the company to explore the possibility of recovery of additional values under conservation and environmental aspects. Hence the company has sponsored a bulk sample for beneficiation studies in the Modern Mineral Processing Laboratory and Pilot Plant of Indian Bureau of Mines at Nagpur, India. The main manganese minerals present in these mine rejects have been identified as pyrolusite and psilomelane. The purpose of this study was to explore the possibility of evolving a suitable beneficiation flowsheet to obtain manganese concentrates assaying over 72% MnO2 to be used as raw material for the manufacture of dry cell batteries.The sample/material was subjected to characterisation studies in terms of chemical analysis, granulometry and mineralogical compositions. Based on these characterisation studies, the beneficiation process developed comprised of desliming, jigging and low intensity magnetic separation mainly to reject quartz, silicates and jacobsite. The manganese concentrate thus produced assayed 70.2% MnO2 with MnO2 recovery of 78% and weight per cent yield of 63.5. This natural concentrate could be mixed with the electrolytic manganese dioxide produced by the company and this blend can thus be used as a raw material for the manufacture of dry cell batteries by the end users. The paper deals with the details of test work carried out in evolving the process flowsheet."

Jan 1, 2003

By F. W. Jessen, C. C. Patton

Adsorbed films were formed on polished stainless steel specimens from dilute benzene solutions of two crude oil distillation residua. Although the two residua were extremely dissimilar in composition, contact angle measurements showed that the two films increased the wettability of the steel specimens to oil by equal amounts. Furthermore, the wettability of the films was essentially unaffected by the desorption techniques used. Paraffin deposits were formed from heptane-wax solutions on the same stainless steel specimens. These deposits definitely adhered to the surface. Presence of an adsorbed crude oil film on the metal surface increased its free surface energy and resulted in increased deposition of paraffin. The addition to the heptane - wax solution of small amounts of the same distillation residua that were used to form the adsorbed films resulted in decreased cohesive strength in the deposits formed, which resulted in decreased deposition. The presence of a crude oil fraction both in the solution and as a preadsorbed film eliminated the adherence of a deposit of any kind. A mechanism of deposition is proposed which explains the results obtained. INTRODUCTION The natural formation of any predominantly organic accumulation in oilwell tubing, surface flow lines or other production and storage facilities is called a paraffin deposit. These deposits restrict the production of crude oil, causing a substantial increase in production costs because of decreased flow capacity, expense for periodic deposit removal and unproductive downtime. The conditions under which such deposits form, their physical characteristics and the nature and severity of the problem created are extremely varied. Over the past several years, much progress has been made in developing and utilizing methods to remove accumulated paraffin deposition. However, like so many other problems, the basic stumbling block appears to be a lack of understanding of the fundamental mechanism involved in the formation of such deposits. Crude petroleum is known to contain considerable quantities of polar, surface active substances which Doddl has shown to be present at the oil-water interface. Denekas, Mattax and Davis2 observed that the wettability of reservoir rocks was drastically altered by exposure to crude oil fractions; and Zisman, et a1.3 showed that the nature of the compounds adsorbed on a surface would determine its wettability characteristics. Cole and Jessen4 and Ehrig5showed that surface wettability can have a profound effect on the magnitude of paraffin deposition, and Parks6 demonstrated chat the presence of certain adsorbed films on a metal surface would reduce the adherence of paraffin to that surface. Zisman7 has since advanced the theory that the conditions for adhesion are the same as for wetting. Therefore, it was felt that there was adequate evidence to support the supposition that adsorption of compounds from a crude oil might play an important part in paraffin deposition. ADSORPTION-WETTABILITY EXPERIMENTS Initial experiments were conducted to determine the effects of adsorption from solution of crude oil residua on the wettability of a polished stainless steel surface. Distillation residua with initial atmospheric boiling points of 700F were used in preference to the whole crudes in order to concentrate on the molecular weight range of interest, and to eliminate the possibility of composition change due to evaporation of the light ends. Also, these high boiling materials would be expected to be adsorbed from the whole oil in preference to similar compounds of lower molecular weight.

Jan 1, 1966

By R. A. Harris

In this study Pt-Al thin films were prepared via electron beam physical vapour deposition (EB-PVD) with an atomic concentration ratio of Pt25:Al75. These films were heat treated at temperatures ranging from 150°C to 650°C for annealing times from 4 to 60 minutes. The resulting microstructure of these thin films were obtained via secondary electron imaging used in conjunction with depth profiling with the aid of scanning auger microscopy (PHI 700).Elemental maps of the micrographs were obtained. Simulations, based on a chemical potential Monte Carlo method1, were run for various interaction parameters. From these simulations theoretical depth-profiles and proposed microstructures were obtained. These were compared to the experimentally measured depth profiles and elemental maps. Keywords Monte Carlo, chemical potential, depth profile, Pt-Al thin films.

Jan 1, 2011

By M. G. Dellow, D. W. Hendriks

"In early 1988 the decision was made by Noranda Minerals Inc. to install pressure filters at the GECO mill to replace the vacuum disk filters and bunker-C fired rotary kiln dryers. Two filters were installed, one for copper concentrate and one for zinc concentrate. Completion of the project was scheduled for the third quarter of 1989. The filters were made operational in October 1989. Some work remains to be done yet on loadout conveyors for total project completion. Capital expenditures for the project have been approximately $2,700,000 to date. The paper describes the selection criteria for the filter, the installation, startup and associated problems.1. INTRODUCTIONThe filter model chosen for the project was the Verti-Press model VP-50-6(7) (Figures1 ,2 and 3) by Filtra Systems of Farmington Michigan, USA. The decision to purchase the Filtra Systems filter was based on gaining familiarity with a different, mechanically simpler pressure filter than the Larox design and to a lesser extent a necessity for repairs to the the disc filter, rotary kiln dryer system used at the GECO operation for its' copper and zinc concentrates. The fact that it is manufactured in North America was an important consideration. The same basic principles of pressure filtration as the Larox machine are used but the implementation is quite different and somewhat simplified with some interesting innovations. 2 filters were installed to allow direct and immediate comparison of the same machine on both fine and coarse materials. Copper concentrate is reground for cleaning on the flotation circuit while zinc is not. Screen analysis of composited samples of concentrates for 1988 indicated that expected copper concentrate would be approximately 66% minus 400 mesh and zinc 50% minus 400 mesh (Tables 1 & 2).The filter is composed of six horizontal chamber module layered vertically and held together in a frame by 1 O large bolts; torqued down to 4000 ft-lbs. 6 individual belts are used; each with its own drive system. The belts themselves are of a 3 piece design with a filter cloth portion, a support belt and a rubberized intermediate portion. They are held together with steel clipper lacings. A basic description (1) of the filter operation is as follows. ""The horizontal filler chamber is closed by hydraulically pressurizing seals across each end of the filter chamber to 200 psi. The feed pump then pumps slurry into the filter chamber. Suspended solids are retained on the filter belt and the filtered solution drains into a lower drip tray and flows from the filter by gravity. At the end of the filtration or feed cycle, a rubber diaphragm in the filter chamber is pressurized hydraulically to 100 psi pressure. This removes all free liquid from the filter chamber and the filter cake. After the diaphragms are retracted the filter cake is blown with compressed air to remove any residual cake moisture. The seals are then retracted and the belt is advanced to discharge the filter cakes. During the cake discharge the belts are washed with a spray header located at the drive end of the filter. The belt assemblies move one (1) complete revolution during the cake discharge cycle. The cycle automatically repeats until the filter is shut down by the operator."

Jan 1, 1990

By Jozef F. Zurawski

Increasingly new interceptors or new Combined Sewer Overflow (CSO) projects require connections to existing tunnels. More often than not, the existing facilities are old, in poor or questionable conditions, without proper construction records or as-built drawings. Many cannot be easily inspected unless major construction effort provides flow by-pass for safe access. This paper provides general guidelines on how to approach the problem of assessing the condition of old tunnels, how to plan and design the connection with limited physical assessment, how to develop the scope of work for the bid documents and how to provide geotechnical guidelines and designs for the bid documents.

Jan 1, 2008

By R Garzon

For resources projects with healthy net present value (NPV) and low cash flow volatility, conventional discounted cash flow (DCF) analysis will continue to provide the dominant investment decision-making criteria. However, DCF analysis can be biased because it often applies a single risk-adjusted discount rate (RADR) to compare the value of projects with different risk characteristics. Many of the difficulties with DCF modelling arise from analystsÆ inability to determine appropriate risk discounts and to estimate expected spot prices inputs for the commodities produced over the life of the project. Modern asset pricing (MAP) is a very valuable complement to DCF analysis in addressing some of these issues. Most papers dealing with MAP, however, while academically rigorous, tend not to be explicit in terms of practical application of this methodology in routine project evaluation. This paper has the objective of reviewing the MAP methodology and of demystifying its complexity, by providing a simple but realistic step-by-step evaluation of a mining project, comparing its DCF and MAP NPV values. The paper concludes that MAP provides a minimum, risk-adjusted æfloorÆ value, thus representing a valuable complement to any DCF valuation.

Jan 1, 2007

By P. A. Riveros, W. D. Gould, R. Molnar, D. W. Koren, P. Bédard

This paper reports the results of the field demonstration campaign of a new process for removing and destroying ammonia from mining/ metallurgical effluent solutions. The 50-day campaign was carried out at a uranium plant in Saskatchewan, Canada. The process was developed by adapting and integrating two well established technologies: zeolite adsorption/ elution to extract the ammonia from the effluent stream and to produce a concentrated ammonia eluate; and conversion of the ammonia in the eluate to innocuous nitrogen by applying bacterial nitrification-denitrification (NH3 = > NO3 - => N2). The data show that reasonable target criteria were met, under very challenging operating conditions. Problem areas and possible causes for poor performance are identified. Preliminary and generic cost estimates of the process are also presented.

Jan 1, 2003

By Chris Tattersall, Tomyuki Kudo, Peter Raleigh, Nestor Garavelli, Steve Redmond, Michael J. Lehnen

Twin bore running tunnels driven approximately 4,500 route feet by a Mitsubishi Heavy Industries (MHI) EPB Tunnel Boring Machine link the West Portal and East Portal on this complex Light Rail Project. One third along the way, the TBM arrives at the Beacon Hill Station which is the deepest underground “binocular” station of its kind in North America and then “walks-across” the station to be re-launched on the other side to complete the drive. This paper discusses briefly the layout and design considerations but then focuses more deeply on the approach by the Contractor to drive and supply the tunnel. The paper addresses the approach used to launch, re-launch and recover the TBM and touches briefly on muck volume control and monitoring plus settlement monitoring and the performance achieved. Also of interest is a unique solution to a difficult launch situation involving a secant pile tieback wall designed with several rows of double I-beam steel walers spanning the eye at the West Portal under the I-5 freeway.

Jan 1, 2007

By H. E. Peterson

Rhenium occurs in very small quantities (12).4 In order for the Federal Bureau of Mines to conduct an investigation of rhenium sources and methods of extraction, it was necessary to devise improved techniques for detecting and measuring minute quantities of the metal. A modification of the procedure of Malouf and White (46) was developed which can be used to detect rhenium in concentrations as small as 0.1 part per million and can be used to measure quantities of 1.0 part per million. It can be used for the analysis of siliceous and calcareous ores, of molybdenite concentrates, of fumes, of flue dusts, and of other metallurgical products. Development of the method involved devising an amine extraction procedure for separating rhenium from all interfering elements except tungsten and a selective distillation procedure for separating rhenium from tungsten. Adoption of these separation procedures permits use of large samples and precise determination of rhenium by colorimetric analysis of the thiocyanate complex of rhenium by means of a spectrophotometer.

Jan 1, 1961

Due to the reduction in frictional resistance, the characteristics of joint infill have a major role to play on rock mass instability. This paper elucidates the laboratory behaviour of graphite infilled joints based on a large-scale shear apparatus under constant normal stiffness (CNS). Discontinuities in a graphite mine have been simulated using high strength gypsum plaster, with the joints infilled with compressed graphite layers. The Fourier series was employed to characterize the joint surface, and the method of using the Fourier coefficients for the prediction of dilation and normal stress with displacement is explained. Die Charateristik von Verbindungsfüllungen hat einen wichtigen Einfluss auf Felsmassenstabilität aufgrund der Verringerung des Reibwiderstandes. Diese Veröffentlichung untersucht das Verhalten von Graphit gefüllten Verbindungen im Labormaßstab mit einer Methode die auf einem gross-umfang Apparateprinzip unter konstanter Normal-Steifheit beruht. Unregelmässigkeiten in einer Graphit Mine wurden mit Gypsum Gips von hoher Festigkeit simuliert, die Verbindungen wurden mit kompressierten Graphitschichten gefüllt. Fourier Reihen wurden angewandt um die Verbindungs Fläche zu Characterisieren. Die Methode die verwendet wurde um die Ausdehnung und Normalkraft mit der Verschiebung mit Hilfe von Fourierkoeffizienten zu bestimmen wird beschrieben. Due à diminution des résistances par frottements, les caractéristiques des joints de remplissage joue un rôle majeur sur les instabilités de la roche. Cet article étudie le comportement en laboratoire des joints de remplissage en graphite à partir d’un dispositif de friction à grande échelle sous rigidité normale constante. Les discontinuités dans une mine de graphite ont été simulées grâce à un plâtre à haute teneur en gypse, dont les joints ont été remplis de couches de graphite compressées. La caractérisation de la surface des joints a été réalisée avec les séries de Fourier. La méthode utilisant le coefficient de Fourrier pour la prédiction de la dilatation et de la compression en fonction du déplacement est également expliquée.

Jan 1, 2003

By M. Dworzanowski

The beneficiation of fine iron ore will increase in importance in the future because most new iron ore resources will be in the form of lower grade ore deposits that will require liberation of iron ore minerals at finer sizes. Generally this fine iron ore will be beneficiated to produce a pelletizing concentrate with very strict chemical and physical specifications. In addition, because of the increasing demand for iron ore there are now more opportunities to produce by-product iron ore from mining operations producing other commodities. In the past the associated iron ore minerals would report to final tailings but now there is potential value to be realised from by-product revenue. These by-product iron ore opportunities are almost all centred on producing pelletizing concentrate. Currently pelletizing concentrates are produced mainly by various combinations of flotation and magnetic separation. The selection of the beneficiation route will depend on ore mineralogy and considerations around plant capacity and final concentrate quality. The main economic iron minerals are magnetic, haematite being paramagnetic and magnetite being ferromagnetic. This, therefore, means that magnetic separation can be applied, in principle, to all fine iron-ore beneficiation plants. While flotation has a considerable capacity advantage over magnetic separation, the real advantage of magnetic separation over flotation in fine iron-ore beneficiation is that treatment of -10 µm iron ore is possible-in flotation, the feed is deslimed at 10 µm and the -10 µm stream is considered to be final tailings, even though there is often a significant amount of contained iron ore. This paper describes a study around the recovery of fine magnetite in the form of a pelletizing concentrate. The study is based on an evaluation of an iron ore by-product opportunity from an iron oxide copper-gold (IOCG) deposit. Experiments were conducted to quantify the differences in magnetic separation performance with decrease in particle size treated. A mineralogical evaluation of all the test work products was undertaken to facilitate the interpretation of the test work results. These results were then used to propose an economically viable flowsheet for maximizing fine magnetite recovery using magnetic separation.

Jan 1, 2012

By Walter S. Bergholz, Michael L. Schreder

"Since Escondida began operations in fiscal 1991, a series of aggressive expansion projects have enabled market share to be increased and ever larger profits to be realized. This was possible due to the very large size of the ore body and its high grade - averaging 2.7% copper from startup through fiscal 1997. The situation has now changed: ore grade is falling rapidly and is projected to be only 1.55% by 2003. Since revenue is directly proportional to ore grade, while costs are proportional to quantity of ore processed, profits will begin to fall dramatically. The Phase IV Expansion Project is intended to forestall this drop in profits by increasing ore processing capacity by over 85%.The Phase IV concentrator is designed for a nominal capacity of 110,000 MTPD and the key to achieving this value is through the proper design of the grinding circuit. This paper presents the general design criteria for the grinding circuit, as well as a description of the facility.INTRODUCTIONThe Phase IV Expansion Project consists of a new copper concentrator located 8.5 km south of the existing operations, a new tailings disposal and water reclaim system, a new concentrate slurry pipeline to the coast, and added concentrate handling capacity at the port of Coloso. The new concentrator has a nominal capacity of 110,000 tonnes per day (MTPD), compared to the existing concentrator’s capacity of 127,500 MTPD. The Laguna Seca concentrator is based on using the largest and most efficient ore grinding mills now available.The concentrator has been designed for a 110,000 MTPD nominal capacity. The process design criteria for the Phase IV project were established from in-house operating information and from test work. Unlike a green field project, Escondida already had an operating plant and it processes ore from the same pit that feeds the Phase IV plant. It is expected that the current mineralization will be similar for the first 6 years of operation of the new project. Therefore, some of the current plant operating conditions were incorporated directly into the design criteria."

Jan 1, 2004

By D. L. Ogonowski, J. O. Marsden

The Candelaria copper-gold mine is located approximately 25 km south and east of Copiapo in Region III, Chile. The original concentrator was designed to treat 28,000 t/d (30,800 stpd) of chalcopyrite-bearing ore through a circuit consisting of a single 11.0 m(36 ft) diameter SAG mill, two ball mills, conventional rougher and scavenger flotation, column cell cleaner flotation, and ceramic disc filtration. The plant was commissioned in August 1994 and quickly reached design capacity and expected levels of metallurgical performance. In May 1996, a decision was made to double the capacity of the concentrator by the addition of a second line of equipment. The expanded facilities were commissioned in October 1997, less than 18 months after the decision to proceed, and well within the budget. The original concentrator facilities were replicated or duplicated as much as possible, however, a number of important equipment changes were made to take advantage of industry developments since the original concentrator was designed. These included the use of Eimco 120 m3 (4,200 ft3) cells for rougher and scavenger flotation and the installation of a Svedala VTM-800Vertimill for regrinding. This paper describes the rationale behind these changes and explores the reasons for the success of the project.

Jan 1, 1999

PERSPECTIVE ?Natural resources exploration, extraction and beneficiation is complex and challenging: ?Input costs rising, complexity increasing, rising stakeholder management needs, regulatory compliance issue, etc. ?With increasing costs and complexity of managing operations are we simply getting less bang for our buck?

May 1, 2013

By C. A. Herbert

During the fiscal year ended September 30, 1932, there were 27 fatalities in the coal mines of Indiana. Four of this number occurred in small mines employing less than 10 men, over which the State Inspection Department has no jurisdiction. In addition to these coal mine fatalities, an explosives accident in a clay mine resulted fatally to one man. Tables 1 and 2, which follow, list the fatalities as to cause and occupation. Table 1. - Fatal accidents by cause, fiscal year ended September 30, 1932 [ ]

Jan 1, 1933

By David A. Summers

The use of high pressure fluid cavitation is investigated as a means of breaking an ore into its constituent grains. This Cavitational Rock Dissagregation (CRD) is found to be possible and effective in breaking down galena ore, both in sandstone and dolomite host material. The technique did not work as well in comminuting and cleaning oil shale, because the cavitation drove the oil into emulsion with the water. The presence of dominant bedding in the rock also caused preferential breakage to these lines, rather than to the individual grain boundaries. This problem was also encountered in tests on igneous ore where weakness plants of the overall ore proved weaker than the boundaries of the individual grains. It was found that the prevailing expression of cavitation erosion dependence on pressure was not absolutely valid. In contrast it was found that CRD is much more sensitive to jet flow diameter, and when this was recognized it was found possible to erode rock with compressive strength of up to 350 MPa with operating jet pressures of 10 MPa.

Jan 1, 1982

By D. D. Tannant

An experimental and numerical study was conducted on the geomechanical behaviour of oil sands during penetration tests in which a steel wedge with an apex angle of either 20 degrees or 30 degrees was forced into compacted oil sands. The boundary conditions simulated in the laboratory tests are similar to shovel penetration into oil sands. The objective of the laboratory tests was to measure the force required to push a steel wedge into compacted oil sands. A wedge penetration test differs from conventional triaxial tests in that much more shear is generated. The laboratory data was needed to improve calibration of micro-mechanical input parameters for a two-dimensional discrete element model of oil sands constructed with Particle Flow Code (PFC). Initial model calibration was performed with triaxial test data and then a PFC model of the wedge penetration test was constructed. The measured force-displacement behaviour of the steel wedge was compared with PFC modelling results. It was found that different combinations of PFC particle and bond parameters could equally well replicate the laboratory triaxial compression data for bitumen-rich oil sands. When the wedge model was run, it was found that the resulting force required to penetrate the wedge into the oil sands was about four to six times higher than that measured. This clearly indicates that further research is required to improve the predictive capability of PFC models of oil sands.

Jan 1, 2002

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