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By H. Qi, J. L. Feng, D. J. Li

"In the present paper, the characteristics of the granite burst under loading/unloading conditions was studied by means of both laboratory experiment and finite-discrete element method (FDEM). After gaining the mechanical properties of the granite samples under uniaxial compression conditions, the parameters taken as input arguments in the FDEM modelling were then carefully calibrated so as to provide some basic data including Young’s modulus, Poisson’s ratio, uniaxial strength, Lame constants, cohesive strength, and frictional angle for further being used in simulating granite bursts. All the simulating results by the FDEM were basically in agreement with that obtained from the uniaxial compression test and triaxial granite bursts in laboratory, respectively. This study shows that that such computational mechanics of discontinua can be employed to gain powerful insight into the failure mechanism of granite burst, which could also be a useful tool to clarify the collapse mechanism of rock structures in rock engineering design and rock test scheme optimisation. INTRODUCTIONBased on discontinuum state a priori, discontinuous modeling techniques that are commonly referred to as discrete element methods (DEM) treat the material directly as an assembly of separate blocks or particles, which was originally proposed by Cundall (1971) and Cundall and Strack (1979) from the viewpoint of analogous molecular dynamics simulation to better account for and understand the interaction between the blocks. The distinct feature of these formulations is that a constantly changing problem of geometry and contact conditions can be addressed by solving the equations of motion using an explicit time marching scheme (most often in a ‘leap-frog’ format), while updating contact force histories as a consequence of contacts between different discrete elements and/or resulting from contacts with model boundaries (Bicanic 1998). The most notable implementations of DEMs are arguably represented by the universal distinct element code (UDEC) (Itasca Consulting Group Inc., 2013) and the particle flow code (PFC) (Itasca Consulting Group Inc., 2012). Another formulation is the discrete crack framework that is based upon some criteria for an advancement of crack front, which is coupled with extensive local and global re-meshing while simulating by numerical methods such as finite element technique, commonly using fracture theories. Certainly, it is relatively easy to trace the propagation of single crack front governed by some principles of energy release rates (Ingraffea 1997) but tracing of multiple cracks leads to topological and algorithmic complexities. Otherwise, there is no consideration of interacting cracks in these formulations of finite element or enhanced finite element techniques (e.g., in XFEM and ABAQUS)."

Jan 1, 2015

By H. R. Huffman

"This paper reviews the history of iron powder production, and outlines the varions production methods. The uses of iron powder and the reasons for its use are also covered. The paper concludes with a look at future trends in powder metallurgy.INTRODUCTION TO POWDERSTHE IRON POWDER INDUSTRY is enjoying a very rapid growth. The annual consumption of iron powder is now at the 100,000-ton level, twenty times higher than it was at the end of World War II, and the yearly in-crease bas been almost consistent at 20 per cent. This is expected to increase, bringing the tonnage to 200,-000, or even (according to some experts) to 270,000, in 1970. In any event, powder metallurgy is expanding at high speed and making an important impact on the production of iron and steel products. Some indication of the faith in the future market may be indicated by the commencement of three new powder production plants in Canada with a total capacity of 136,000 tons annually."

Jan 1, 1969

By C. G. McLachlan

Abstract This paper deals with the application of the cyanide process to recover gold from a pyrite concentrate produced by means of differential flotation. This concentrate before cyanidation contains from 0.09 oz. to 0.14 oz. gold per ton, of which only about 60 per cent is recoverable. The rest is so fine that it remains interlocked in the pyrite and therefore is not acted on by the cyanide. The concentrate also contains about 15 per cent pyrrhotite and 0.4 per cent chalcopyrite, both of which are cyanicides. The cyanicidal effect of the pyrrhotite is inhibited by preacracing the pulp with lime, and maintaining a high lime alkalinity during cyanidation. The effect of the chalcopyrice is reduced as far as possible by removing those particles which are free by means of a further flotation step immediately prior to cyanidation. This involves the flotation of some very fine material. After nullifying as far as possible these two cyanicides, the concentrate is cyanided directly, i.e., without being roasted. This leaves the pyrite available for subsequent sale as a source of sulphur dioxide and sulphuric acid, and the entire residue of the cyamde plant, amounting to about 500 tons per day, 1s now being disposed of in this way. Prior to deciding on direct cyanidation, a number of laboratory roasting tests were made. These showed chat, 1f proper control were exercised, a better recovery of gold could be effected from the roasted product than by the direct method of treatment. The tests also showed that the capital cost o the plant would be much higher than that needed for the procedure adopted. The possibility of subsequently selling the pyrite for its sulphur content would also have been eliminated. Introduction A previous paper has described in considerable detail the application of the flotation process to improve gold recovery from Noranda's milling ore, and in so doing has covered the production of an auriferous pyrite concentrate. The present paper deals with the recovery of gold by cyanidation from that concentrate. This gold, though intimately associated with the pyrite, can, for metallurgical purposes, be considered as all occuring in the native state.

Jan 1, 1946

By M. Bustin, A. Hosseinian, G. Preisig

Hydraulic fracturing and hydraulic shearing techniques are essential for the development of unconventional oil & gas and geothermal resources. Such techniques will also play a key role in the development of CO2 sequestration, and management of high stresses encountered with deep mining. However, the optimal design of hydraulic injections is often limited by continuum treatments of the rock mass without consideration of the influence of the natural fractures present. These may interact with the hydraulic fracture to promote offsets or arrest, or may cause the natural fractures to undergo shear and dilation. Given the limited access to the rock afforded by deep boreholes common to oil & gas and geothermal projects, advanced numerical modeling is critical for understanding key mechanisms and interactions. In this work, we first present a coupled hydromechanical distinct-element model focusing on the propagation of a hydraulic fracture. Normal and shear displacements arising from the generated hydraulic fractures are subsequently integrated into a fracture flow model for detailed analysis of specific flow behaviour and fracture permeability. For this, a scanned 3-D profile of a natural fracture is used to correlate surface roughness to dilation as a function of shearing. Fracture flow is computed at different time steps corresponding to different fracture propagation states and geometries. Modeling results indicate that the opening of a tensile hydraulic fracture is accompanied by millimetre-scale shear displacements associated with slip and wedging between adjacent blocks. This may leads to a mismatch between the upper and lower walls of the fracture if asperities are irregular and strong enough. However, fluid-induced tensile fractures have low Joint Roughness Coefficients (JRC), and associated millimetre-scale shear displacements are too small to ensure a significant offset of asperities that prevent a fully-elastic closure when the hydraulic fracture is depressurized. Injection of proppant is thus critical to keeping hydraulic fracture apertures open. Future work is planned that will see the models calibrated against field data including microseismic event locations, magnitudes and source mechanisms, tiltmeter deformations, stress change, and pore pressures.

Jan 1, 2015

By A. G. Roach

HISTORY AND LOCATION SEAL HARBOR GOLD MINES, LIMITED, was incorporated in January, 1934, to take over 116 acres of mining lands in the Stormont gold district, Guysboro county, Nova Scotia. The nearby ten-stamp Mulgrave mill was also purchased, and since that time 974 acres of adjoining properties have been secured from the Government by direct lease. The property is served by a motor road and is about two miles from the village of Goldboro, situated on the shore of Isaac's harbour. The bulk of ?the supplies are brought in by coastal steamer from Halifax, a distance of about 100 miles, since the nearest railway connections are at Antigonish, some 40 miles distant. EARLYY WORK The Seal Harbor properties include the old Partington and Beaver Hat mines. A small tonnage of ore was mined from each and treated on the properties in stamp mills, which were later torn. down . A survey of old records shows that this ore averaged about $8.00 gold per ton. Development work by the present Company was confined to the 100-foot level until February, 1935, but after that rime the incline shaft was deepened to 425 feet and the 300-foot level was explored east and west of the shaft. Six belts of ore were intersected to the west of the shaft. The ore from these belts was hand sorted and the ore portion was put through the 10-stamp Mulgrave mill to defray operating expenses and to serve as a sample of the deposits. The average recovery per ton from this sorted ore was $6.10. Samples of the ore were sent to the testing laboratories of the Mines Branch, at Ottawa, and of Canadian Industries, Limited, at Toronto. Recommendations from both of these authorities were for removal of the coarse gold by concentration and barrel amalgamation, followed by cyanidation of the residue.

Jan 1, 1937

By R. E. Eyre, L. P. Landucci

C URRENT practice in the zinc concentrate roasting plant of The Consolidated Mining arid Smelting Company of Canada Limited, at Trail, B.C., involves passing the furnace effluent gases through an electrostatic precipitator for the recovery of dust. After removal of the dust the gas is treated for recovery of sulphur dioxide by conversion into sulphuric acid ( 1). However. as roasting techniques improved, and furnace productivity in-creased, the rated capacity of the precipitator was exceeded and it was necessary to consider various means of improving the dust recovery. A study of methods indicated that a baghouse using silicone-treated glass fabric, might be suitable for this particular application. Glass fabric was chosen because the temperature of the roaster effluent gases would range from 450°F to 500°F and tempering air was undesirable to avoid dilution of the sulphur dioxide gas.

Jan 1, 1962

By Du Xinfeng

The resource quantity of the low rank coalbed methane (CBM) accounts for 47% of the total resource quantity of CBM in China. Compared with the exploration and development of the high rank CBM in Qinshui Basin, China and the low rank CBM in Powder River Basin, USA and Albert Basin, Canada, the exploration and development of the low rank CBM are still in the initial test stage. In this paper, on the basis of analyzing the mining geological conditions such as that the Huanglong Jurassic Coalfield is largely situated in the hills and gullies zones, and the coal reservoir has the features such as the low metamorphic degree, large coal seam thickness, simple coal matrix texture, high permeability and small CBM content and so on, it discusses the key technologies such as the development pattern of CBM, well location arrangement, drilling and well completion technology and fracturing technology and so on. It indicates that the underbalanced drilling and the cavity well completion based on the reservoir protection will be the development directions of the CBM development technology in this area.

Aug 1, 2013

By Tim Mann

"Like other operating mine sites, Placer Dome Inc. - Campbell Mine has taken important steps over the last few years to address environmental issues.This paper will provide specific insights into the implementation of an environmental management system at Campbell. In particular, it will focus on how Campbell developed its plan of action; the lessons that have been learned; the over-all steps that are being taken to enhance environmental stewardship and effectively manage relationships with key stakeholders.IntroductionThe development of an Environmental Management System at Campbell Mine has been part of a general development in management practices which has taken place at the mine during 1990. This paper will discuss the components of the management system in the topic areas of: direction setting; environmental organization; issue assessment; emergency response plan; training ; monitoring/verification; reporting and data management; and relationship management.Although this paper focuses on environmental management systems, the development of this system has partly been a function of responses to other issues which have been addressed concurrently with environmental concerns. These other issues include development of operations management, human resources practices, and safety management practices at the mine. As the Environmental Management System developed, various stakeholders associated with local environmental concerns were identified. This group of stakeholders include the local community; municipal, provincial and federal governments; government agencies; Campbell employees; and the Placer Dome Inc. Corporation."

Jan 1, 1991

By M. A. Perras, H. A. Kasani, G. Walton

The development of an underground repository for the storage of spent nuclear fuel relies on a multi-barrier system to isolate the used fuel from the environment – ultimately, the biosphere. These barriers include engineered copper and steal canisters, dense bentonite, and the natural rock as well. In order to reduce the potential flow pathway along the excavation induced damage zone, various slots perpendicular to the excavation axis have been proposed. These slots are called cut-off seals and generally are filled with bentonite as it has high swelling potential and very low permeability. Many different geometries have been proposed, but clear guidelines on the selection of the optimum geometry have yet to be developed. In order to assess the optimum geometry, three shapes have been selected for this numerical study, including a trapezoid, a triangle, and a thin rectangular slot. The cut-offs were modelled for a conceptual shaft constructed in the Queenston Formation from Ontario over a stress to strength ratio that has been found at many underground research laboratories. It was found that the excavation of a triangular and thin slot cut-off had the smallest increase in the damage as quantified based on the extensile volumetric strain within the plastic yield zone. Both shapes showed an increase in the damaged zone by 13 cm at a stress to strength ratio of 2.75. The trapezoidal cut-off damage zone increased by 20 cm at the same stress to strength ratio. Further study is required to better define the optimum cut-off shape for wider variety of conditions and other geological formations.

Jan 1, 2020

By H. S. Price, F. N. Kissell, R. C. McCulloch, J. C. Edwards

"The methane em1ss10n from deep coalbeds which are actively mined is a serious problem facing the mining industry today. Pinpointing the source of methane and predicting the emission of this gas from these coalbeds is necessary if preventive techniques are to be effectively used to control methane emission. In general, because most coalbeds have water associated with them, the system to be studied may be either single-phase (methane gas) or two-phase (methane and water). Because coal mine geometry is complex and the fluids have variable properties as functions of pressure and methane concentration, the differential equations describing the flow of methane and water are not amenable to analytic solution, but must be solved numerically using high-speed computers. This paper presents the development of such a complex mathematical model along with some preliminary applications of the model to methane emission from one- and two-dimensional coalbeds with and without water present."

Jan 1, 1973

By J. H. Morrish

"The delivered price of any mineral is the determining factor in converting untapped resources into economic resources. Transporting the minerals from the mine to the market plays a significant part in the total package. The expansion of the Western minerals industry in the last ten years has been paralleled by improved transportation systems to reduce cost, increase accessibility of resources and get the minerals to market in the shortest time possible. A review is made of developments, such as unit trains, complex multi-modal systems and containerized transport, over the last ten years, with specific movement outlined. The total transportation package of land transport, port and terminal facilities, and water transport, where needed, is stressed. As the volume of minerals movement expands, increasingly sophisticated and integrated transportation systems will have to be utilized. The development of solids pipelines and other possibilities is outlined."

Jan 1, 1973

By J. A. González-Anaya, F. Nava-Alonso, O. Alonso-González, F. Alvarado-Hernandez, A. Uribe-Salas, C. Jimenez-Velasco

"One of the most common hydrometallurgical methods for precious metal extraction is cyanidation. The effluents of this process may contain relatively high concentrations of copper, zinc and iron, which react with free cyanide to form complexes, adversely affecting the efficiency and the economy of the process.This preliminary work studies the use of the solvent extraction technique to remove copper, zinc and iron cyanide complexes from a synthetic solution similar to that of gold mill effluents, in order to allow the recycling of the solution back to the process. For the extraction of these anions (Cu(CN)2 -, Cu(CN)3 2-, Cu(CN)4 3-, Zn(CN)4 2- and Fe(CN)6 3-), trioctyl methyl ammonium chloride (Aliquat 336) was studied as extractant, using nonylphenol as modifier in the organic phase (iso-octane). The experimental results showed that for a synthetic solution containing 450 mg/L total cyanide, 160 mg/L copper, 50 mg/L zinc and 51 mg/L iron, it is possible to extract the 96% of copper, 91% of zinc and 75% of iron when using 0.011 mol/L of Aliquat 336 (organic/aqueous volume ratio (O/A) =1) in the pH range of 9-10."

Jan 1, 2014

By R. B. Nourse, R. Hundermark, B. Masters, H. Joubert

The new 30 MVA slag cleaning furnace at Waterval Smelter, Rustenburg Platinum, South Africa, has been in operation since 10 March 2003. The furnace design and operation face a number of challenges including a wide variety of feed materials and resulting bath conditions. Furnace feed varies in combinations of granulated Waterval Ausmelt Converter Slag (WACS), hot fed Peirce-Smith converter slag, concentrate and reverts. Coke is added as reductant. The resulting slag composition varies considerably and regularly. For the case feeding WACS an almost pure fayalitic slag (60%+ FeO, 30%+ SiO2) with a very low viscosity results. Due to the widely varying slag conditions, including a superheated fayalitic slag with high fluidity, a robust sidewall design is required adjacent to the slag bath. For this reason the furnace sidewall is equipped with Pyromet's MAXICOOL® high intensity copper cooling system. The design and installation of the copper coolers as well as tap holes are discussed. To cope with the variation in bath conditions and high slag superheat (350°C when tapped at 1650°C), the copper coolers are capable of removing peak sidewall heat fluxes above 500 kW/m2. Feedback is included on the performance of the Pyromet MAXICOO® copper cooling system for the first two years of operation. The paper further includes an overview on the design and performance of the tap holes, furnace shell, furnace roof and copper slag spouts.

Jan 1, 2005

By F. Siciliano, D. Bai, S. Yue, A. M. Elwazri

The influence of niobium addition and very low temperature (`cool') deformation on the microstructure and properties of low carbon microalloyed steels was investigated. In this work, the specimens were heated at 1200°C and held at this temperature for 20 minutes. Some specimens were aged at 400°C for times ranging from 10 minutes to 10 hours followed by air-cooling. Others were subjected to deformation at 400°C (`cool deformation') prior to aging. It was observed that the proportion of acicular ferrite was increased as the amount of Nb was increased. It was found that cool deformation increased both yield and tensile strengths significantly compared to that of the aged only specimens.

Jan 1, 2005

By Joël Kapusta

La pyrométallurgie du cuivre est essentiellement une chaîne de trois étapes successives d’oxydation préférentielle du fer et du soufre et des impuretés moins nobles que le cuivre qui sont contenues dans le concentré de cuivre issu de l’usine de concentration du minerai, aussi appelée concentrateur. La Figure 1 illustre la chaîne complète d’élaboration du cuivre depuis la mine jusqu’au cuivre pur. La voie hydrométallurgique traite le concentré par lixiviation, c.à.d. par dissolution en phase aqueuse à température typiquement inférieure à 100 ou 150⁰C, alors que la voie pyrométallurgique traite le concentré par fusion à température de l’ordre de 1200 à 1300⁰C.

May 2, 2024

By J. Coffin, M. Muinonen, D. Fragomeni, R. Multani, C. Deredin

"Rejection of pyrrhotite from pentlandite is of critical importance to the economics of nickel concentrate production and the main goal of the Strathcona milling operations. A joint team of XPS, Glencore Technology and Strathcona Mill personnel executed a comprehensive program of work to develop and implement strategies for increased Po rejection with focus on challenging ores containing high feed Po/Pn ratios (> 7) and significant hexagonal Po content (> 40% of total Po). This paper describes the team results including minerology, bench-scale flotation tests, and plant validation tests and modeling that have defined the path forward to improving the metallurgical performance and economics of the mill operation. Techniques to quantify hexagonal and monoclinic pyrrhotites were developed at XPS to assess the differences in their metallurgical behavior since their flotation responses are quite different. Mineralogical tools including QEMScan were extensively used to determine mineral liberation, associations, optimum grind size, and nickel deportment into pentlandite, pyrrhotite and non-sulphide gangue. Several reagents/strategies were evaluated during bench-scale flotation testing to significantly increase Po rejection. A significant shift in the Po-Pn selectivity and grade recovery curves was achieved using several strategies including the use of DETA and sodium metabisulfite, and regrind of the rougher concentrate and rougher cleaner/rougher tails.INTRODUCTION The Strathcona Mill is owned and operated by Glencore Nickel – Sudbury Integrated Nickel Operations and has been processing Ni-Cu ores from the Sudbury Basin since 1968 (valuable sulphides: pentlandite (Pn) – (Ni,Fe)9S8 and chalcopyrite (Cp) – CuFeS2). Currently Strathcona Mill receives ore mined from two main sources in the Sudbury area and produces two concentrate streams – a nickel-copper concentrate that is shipped to the Sudbury Smelter and a copper concentrate that is sent to the Fonderie Horne (Glencore Copper, Rouyn-Noranda). The general flowsheet currently used at Strathcona is displayed in Figure 1. It is highlighted by separate feed circuits for regular grade Ni ores and high grade copper ores. The copper circuit has a preflotation stage prior to a rougher-scavenger stage, a copper-nickel separation circuit, and a pyrrhotite (Po) rejection circuit."

Jan 1, 2018

By A. Longval, Q. Jiao, T. Shannon

In 2000, Xstrata Zinc (former Falconbridge Ltd.) Brunswick Smelter commissioned a modified lead blast furnace. Since then, efforts have been made to improve its operation in order to achieve optimal operation in terms of coke consumption, lead loss to slag, and improved environmental and hygiene conditions. This paper will review the important step changes in operational philosophy, undertaken since 2004, for the control of the blast rate, oxygen enrichment in blast, slag chemistry and charge level. Furthermore, a review of the improvements made in secondary materials consumed at the blast furnace will be made. This paper will also discuss the significant reduction of the frequency of accretion removal as a result of improved furnace operation.

Jan 1, 2008

By M. Noaparast, N. Nickoletopoulos, André R. Laplante

"This paper presents an application of the use of synthetic ores to study gold recovery by gravity. Three case studies are presented: the first focuses on the use of tungsten to study applications of Knelson Concentrators for upgrading gravity concentrates; the second on tungsten again, in this case to study the performance of a 86 Falcon Concentrator; and the third on lead to mimic gold's grinding behaviour.It is shown that the use of synthetic ores with metallic substitute for gold is not only expedient, but it can also lead to an increased understanding of separation and grinding mechanisms, because of the more accurate results and controlled particle shapes. The case studies highlight the problems associated with gold particle flakiness and gangue density. The grinding behaviour of malleable materials is shown to be complex, as particles can migrate to coarser size classes by flattening and cold welding, and to finer size classes by folding and actual breakage.IntroductionThe title of this contribution is not entirely misleading. Mineral processing has much to do with philosophy, rather Philosophy, as described by Georgius Agricola:""Furthermore, there are many arts and sciences of which the miner should not be ignorant. First there is Philosophy, that he may discern the origin, cause, and nature of subterranean things; for then he will be able to dig out the veins easily and advantageously, and to obtain more abundant results from his mining. ""1"

Jan 1, 1995

By J. Elderton

"The combination of A C induction motor and flu id coupling, of either the fixed or variable filling type, constitutes a simple, low cost, highly reliable drive unit, with many applications in the mining field.The paper will, however, concentrate on the variable filling fluid coupling in three principal applications-conveyor starting, infinitely variable speed control for slurry and slimes pumping and dewatering pumps for deep mines. Fluid couplings can be used with standard or custom-built control gear equipment, ranging from the most simple, time-based open loop types, to those having the latest microprocessor techniques.IntroductionThe first industrial applications of fluid couplings included their use in the mining field as hydraulic slip regulators for flywheel generating sets. These installations, usually rated at around 1700 to 2500 hp, were located at mine shafts where the electrical grid transmission lines were not strong enough to cater for the peak power demands of the cage winding cycle. In Canada, the first two significant examples of variable filling fluid couplings for mining were on conveyor drives, at Steep Rock Mines Limited, closely followed by the major iron ore handling term inal on the St. Lawrence River at Sept-Iles. Successful and reliable operat ion of the fluid couplings at these two sites set the pattern for use on many subsequent mining projects throughout the Canadian Continent."

Jan 1, 1986

By Erwin L. Zodrow

"IntroductionThrough an extensive coal sampling project in the Sydney coalfield of Nova Scotia during 1981 - 1984 involving a majority of the mineable coals (Zodrow, 1985, Fig. 1), a sizeable inventory on trace, minor and major metals was established. In this paper, results of studying the inventory are summarized, concentrating mainly on the relationship that exists between metal variations and thickness of coal channel samples (i.e. trends) and on explaining the trends in geochemical and sedimentological terms. As an over-all conclusion the Everglades peat of Florida is proposed as a modern-day analogue to Upper Carboniferous peat swamp development that took place in the Sydney Basin.Data InventoryFor this study 17 channel samples were cut , 8 cm to 14 cm channel width and 8 cm to 10 cm depth, from 10 successive coals which in stratigraphically descending order are as follows: Point Aconi (3), overrider Lloyd Cove (2), Lloyd Cove (2), Stubbart (2), Harbour (4), Backpit (I), Phalen (,I), Shoemaker (1) and McAulay (I), where bracketed values signify the number of channel samples cut from a seam (Zodrow, 1985, Fig. I). Each channel sample was subdivided by 15 em incremental length yielding a total sample size of 137 for analysis. By appropriate modern techniques these samples were analyzed to determine concentration levels for 32 chemical elements and ash content, the average results of which are presented in Table 1.Tests were also made for Pd, Pt, Ga, Nb, Cd, Cs, Sm and W but their concentration levels in many instances hovered on the lower detection limits that were used and on this accounts are excluded from discussion. Ashing, when necessary for the determination of concentration levels, was done for 12 hours at a temperature not exceeding 450°C. Concentration levels for the elements are reported in reference to whole-coal or whole-coal equivalents and discussed on this basis. In the course of the analyses, lower detection limits received careful attention."

Jan 1, 1986