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By M. Al Mukhtar, D. Hoxha, X. Brunetaud, D. P. Do, C. Auvray, L. Michel

"Mechanical behavior of rock joints is often the key factor governing the response of complex structures constructed in fractured rock masses such as underground openings or of objects assembling various stones blocks such as historical building walls or damaged marble statues. This paper aims at developing a theoretical model to describe the behavior of fresh joints based on the description of their morphology. The main idea of the model is to establish a link between the effective contact surface of joints and the frictional coefficient. Beginning from a chosen level of joint surface description where a joint is considered as “smooth”, the model describes the added friction with respect to the increase of the contact surface of the joints and the distribution of stress in these contacts. The model developed initially for asperities with regular geometry is firstly compared with existing models and then applied on fresh artificial joints. For that, healthy artificial joints have been characterised using in one hand classical CNL shearing tests and in another hand the morphology of joints. The joints surfaces are digitized before testing using a high resolution laser scanner (Konica Minelota Vivid 910) allowing to obtain a precision up to 10µm. From these scanned surfaces the morphology of joints is characterised on the profiles running in the direction of shearing and a mean value of friction is calculated using the developed model. This calculated value is then compared with that obtained from CNL shearing test and a good approximation is notedINTRODUCTIONThe role of the mechanical behavior of rock joints on the overall response of fractured rock masses is well established in many fields of engineering activity going from the stability of underground constructions (Souley M, Hoxha D, Homand F 1999), rock slope stability (Einstein H.H. Veneziano D., Baecher GB., O’Reilly K.J, 1983, Jaeger 1971), various rehabilitation of masonry construction, damaged stone artworks restoration (Michel L., Do D.P, Coignard B, Hoxha, 2014) and so on. In the same time the characterisation of the behavior of joints and their modeling is nowadays a dynamic field of research or/and investigations and many alternative approaches have been proposed (Barton, N.R. and Choubey, V. 1977, Tatone, S.A. Bryan, Grasselli Giovanni 2010, William C E. 2007). While empirical relations of shear strength with various parameters of the joint morphology are the most used in practice because of their simplicity (Barton. and Choubey, 1977, Barton 1973, Bandis S., Lumsden A. C. and Barton N. R. 1983) many other models of joint strength are developed based on mechanistic considerations (Haberfield CM, Johnston IW. 1994), multiscale approaches (Yang Z.Y., Di C.C., Yen K.C. 2001, Fardin N., O. Stephansson, Lanru Jing 2001) or micromechanical ones (A. Serrano, C. Olalla, R.A. Galindo 2014) to mention just a few of research trends on rock joints modeling."

Jan 1, 2015

By S. L. Chen

The Kumera Technology Center developed a unique type of steam dryer for drying copper concentrate in the mid 1990s. The dryer has been chosen in several copper smelter projects since 1999. To expand production capacities, the Norddeutsche Affinerie smelter, the Pirdop smelter of Cumerio, the Toyo smelter of Sumitomo Metal Mining and the Tamano smelter of Hibi Kyodo Smelting have carried out projects in which Kumera Steam Dryers were installed. The capacity of a single steam dryer varies from 70 t/h to 160 t/h. This article summarizes the latest operation results of the Kumera Steam Dryers in these smelters and introduces the progress of the ongoing projects in Yanggu Xiangguang Copper, Guixi smelter of Jiangxi Copper, Jinlong Copper, Boliden Harjavalta, and Onsan smelter of LS-Nikko Copper.

Jan 1, 2007

By M. E. Grimes

"The future of the uranium industry in Canada during the next twenty years will be very dependent on political and social issues on a world scale. Technology, as such, will tend to be of lesser importance. Nonetheless, some technical changes can be anticipated.This paper deals with milling of uranium ore, leaving further processing and nuclear power production to specialists in these fields. An attempt has been made to look at uranium production technology in Canada in relation to that in other countries, and to draw interference regarding future changes that seem probable in the Canadian context. In particular, recent advances in mill equipment are considered.The chemistry of uranium and its relatively low concentration in most ores has been responsible for a completely hydrometallurgical approach to mill processing, and this should continue. In spite of little commercial success to date, pre-concentration of lower grade ores will be researched further in order that these ores can compete with higher grade deposits in Canada.The discovery of the relatively high-grade ores of the Athabasksa region will undoubtedly influence choice of mill processes and equipment. The potential effect on innovations is discussed"

Jan 1, 1986

By A. M. Salomon de Friedberg

With respect to impurities, HBM&S' copper smelter, located in Flin Flon, Manitoba, is in an unusual position. In addition to the usual concerns, the fact that copper and zinc production at Flin Flon is closely integrated results in the unique situation where feed to the copper smelter typically contains 7% to 8% zinc. This paper discusses the ramifications to copper smelter operations resulting from the marriage of HBM&S' metallurgical plants. Distributions of impurities (specifically Zn, Pb, Ni, As, Bi, Sb, and Cd) are presented and operating practices designed to reduce the impact of impurities on anode copper quality are detailed.

Jun 1, 1993

By A. M. Salomon de Friedberg

"With respect to impurities, HBM&S' copper smelter, located in Flin Ron, Manitoba, is in an unusual position. In addition to the usual concerns, the fact that copper and zinc production at Flin Ron is closely integrated results in the unique situation where feed to the copper smelter typically contains 7% to 8% zinc. This paper discusses the ramifications to copper smelter operations resulting from the marriage of HBM&S' metallurgical plants. Distributions of impurities (specifically Zn, Pb, Ni, As, Bi, Sb, and Cd) are presented and operating practices designed to reduce the impact of impurities on anode copper quality are detailed.IntroductionHudson Bay Mining & Smelting Co. Ltd. (HBM&s), has been operating its metallurgical complex located in Flin Flon, Manitoba, since 1930. The smelter and zinc plant were originally separate entities with respect to production. The smelting operation consisted of traditional multiple-hearth roasters, a reverberatory furnace and Peirce-Smith converters. The zinc plant also utilized multiple hearth roasters and then followed with sulphuric acid leaching, purification and electrowinning. The zinc plant also recovered cadmium from a separate purification/electrowinning circuit.The two plants operated essentially independently of each other until rising zinc levels in the copper concentrate and large stockpiles of zinc-rich leach residues prompted the construction of the fuming plant in 1949. The smelter used pulverized coal to reduce zinc oxide present in the reverb slag and then captured the resulting zinc bearing fume in the fuming plant baghouse. The fume was sent to a separate ""oxide roaster"" in the zinc plant where it was first roasted to remove halogens and then leached to recover the contained zinc. This oxide fume became a major source of feed to the zinc plant accounting for roughly one quarter of the total zinc production. Furthermore, through the smelter's treatment of sulphide leach residue, both copper and zinc recoveries were improved for the over-all complex."

Jan 1, 1993

By C. B. Webber, L. S. Diaz

"The paper presents the approach taken by Craigmont Mines to grinding circuit control. A detailed description is given of a fully automatic control system which bases its control actions on the continuous measurement of particle size in the cyclone overflow stream. The control system holds a specified particle size in the cyclone overflow, and grinds rod mi 11 ore feed at increased rates. The principles of operation of the system used for continuous measurement of particle size are described, end the improvements in mill throughput and copper recovery over several months of continuous operation are presented.INTRODUCTION Craigmont Mines Limited is located in the south-western interior region of the province of British Columbia, approximately 230 road miles north-east of Vancouver, and ten miles west of the town of Merritt. A moderate climate, good roads and service facilities provided by the Canadian Pacific Railway, Inland Natural Gas Company, and the B.C. Hydro and Power Authority, have provided a very favorable mine and plant site.The preliminary metallurgical design of the Craigmont mill was based on the test results of samples obtained from the original 2500' level drift during 1959. Pilot plant runs and other research testing for design pur¬poses were conducted at the Canadian Exploration Ltd. Laboratory, at Salmo, B.C. The design flowsheet was altered in progressive stages from 2,000 to 3,000, and finally 4,000 tons per day as the ore reserves became better defined. Construction work on the 2,400' level mill site commenced in late 1960. The official opening of Craigntnt Mines Limited took place on September 15, 1961, a little over two years from the time of the metallurgical assessment of the original ore samples.Mill throughput to date has varied widely both on a daily and a monthly basis, due to the varying hardness of the mine ores. The grindability af the ore appears to be related to the oxide iron content, which varies from lows of 9% to highs of 20%. Daily tonnage has ranged from 5,000 tons per day with 10% iron in the feed, to 6,000 tons per day with 20% iron feeds."

Jan 1, 1973

By F. A. Auld

"During the period 1958-1980 seven deep shafts were sunk from the surface in the UK. From 1977 until 1989 sixteen deep shafts were sunk in the UK, all concrete lined. Subsequently from 1989 up to the present day no deep shafts have been sunk in the UK, a period of 30 years. Developments in the design and construction of deep shaft linings in the UK therefore were predominantly carried out throughout the period 1977–1989. This knowledge is recorded in several published papers by the author over that period which will be referred to in the paper. INTRODUCTION The paper includes a review of past precedent for the design of deep shaft concrete linings in the UK and sets out the principles for future designs, including the design load to be adopted and Factors of Safety (SFs) to be used in the design. Hydrostatic pressure increases with depth from the surface and therefore the concrete lining must increase in thickness and strength throughout its depth to resist the pressure. High strength concrete mixes were developed to enable economic linings to reach greater depths and these will be detailed. The ground conditions to sink through in the UK consist of predominantly competent (self-standing when excavated) rock, which can be water bearing, and hence a hydrostatic pressure resisting lining is required. The paper describes the construction measures needed to produce a dry shaft by way of pour length, joint detail, backwall grouting and joint sealing details. PAST PRECEDENT FOR UK DEEP SHAFT SINKING AND LINING Seven deep shafts were sunk from the surface in the UK from 1957–1977 over a 20-year period (Auld, 1987). These are listed in Table 1. Three shafts were for British Coal, two were for Cleveland Potash Ltd and two were for the Central Electricity Generating Board. The British Coal shafts were 5.486 m and 7.315 m internal diameter to depths of 550 m and 780 m, respectively. At 5.5 m internal diameter and a depth of 1150 m, the two Boulby Mine shafts for Cleveland Potash Ltd are currently the deepest shafts in the UK. The two Central Electricity Generating Board shafts of 5 m and 10 m internal diameter, to depths of 255 m and 440 m, respectively, were ventilation shafts for a pumped storage scheme. Six of the shafts were sunk by Thyssen (GB) Ltd and one by Cementation Mining Ltd."

Jan 1, 2019

By P. L. Li, B. X. Song, C. H. Wang, T. Wang, Z. Hu

"The treatment of an oxidized copper-gold ore by stage cyanide addition was investigated. For cyanidation, free cyanide ion concentration can be an indicator of whether there is copper dissolved in cyanide solution, and maintaining the free cyanide ion concentration lower than 1.0 g/L could be an effective way to prevent copper dissolution and reduce cyanide consumption. For that purpose, stage cyanide addition was introduced to control free cyanide ion concentration within the range from 0.8 to 1.0 g/L. Cyanidation tests results indicate that gold extraction was still acceptable at reduced cyanide consumption with a lower copper extraction. Based on the experimental study, industry application works at Beiya concentrator of Yunnan province, China were successfully conducted. When the raw ore contains 2.95 ppm Au and 0.75% Cu, by stage cyanide addition method, the gold extraction was still 93% at reduced cyanide consumption of 2135 g/t, which was only half of one addition method, and the copper extraction dropped to only 5%, which indicated that dissolution was prevented for almost 75% of the malachites.INTRODUCTIONCyanide with its competency to form a strong complex with gold, is the most preferable lixiviant for gold leaching. However, cyanidation is not inherently a selective process since many other minerals present in the ore are also readily soluble, especially the copper minerals. Muir (2011) reported that every 1% reactive copper present in the ore consumes about 30 kg/t NaCN, which can have detrimental effects on the process efficiency and economics due to high cyanide consumption, reduced gold leach rates and poor gold recovery."

Jan 1, 2016

By Z. Zhang

Aluminum boron carbide particulate reinforced composites have found new applications in nuclear industry due to their special capability to capture neutrons, Recently, Alcan successfully developed a liquid metal mixing process to fabricate Al¬B4C metal matrix composite instead of powder metallurgical technology. In the process, titanium is added into the composites to control interactions between boron carbide particulates and aluminum matrix, To understand the effects of titanium on the composites, the solidification microstructure of Al-16%B4C without or with titanium was examined by optical and electron microscopes. The results show that titanium can improve the uniformity of the particulate distribution within aluminum matrix if the titanium content in the composites is more than 0,5%, Furthermore, it is found that the layer with rich titanium on the surface of the particulates can limit the formation of AlB2 type compounds, which may greatly deteriorate the fluidity of the composites, In addition, it is also found that the amount of the reaction products in the composites increases with the increase of holding time. However, the rate of the increase is mitigated by the increase of the content of titanium in the composites. Besides, a procedure was proposed and implemented for the evaluation of uniformity of particulate distribution within aluminum matrix.

Jan 1, 2005

By R. A. Crouse

The Tanco pegmatite at Bernie Lake, in the Lac du Bonnet mining district of southeastern Manitoba, is a unique deposit of Li, Rb, Cs and Ta, with substantial reserves of Be and several industrial minerals. This paper summarizes the present state of understanding the regional geology, structural setting, zoning, mineralogy and geochemistry of the pegmatite, and the mining and ore-processing methods used in its exploitation.

Jan 1, 1979

The Cooperative Research Centre for Mining Technology and Equipment (CMTE) is funded by the Commonwealth Government, by its mining research members Ñ the Universities of Queensland and Sydney and the CSIRO1, and by its industry members Ñ BHP Coal, RioTinto R&TD, Hamersley Iron, Mining Technologies Australia, Pasminco, Shell Coal, WMC Resources, Advanced Mining Technologies, and Aberfoyle. The Centre conducts work aimed at improving the competitiveness of the Australian mining industry. The current work is focused in four areas: new mining and drilling systems, geological sensing, automation, and equipment maintenance and reliability. This paper describes much of the work in these program areas that relates to metalliferous mining.

Jan 1, 2001

By O. Lashkari

Manipulation of pouring temperature is an efficient way to produce different microstructural features. In order to characterize the microstructure of rheocast billets due to different superheats of 615-695 °C, the parallel plate compression method was employed. Foundry 356 Al-Si alloy with different morphologies of primary a-Al particles were tested at different initial pressures of 4,8, 11,2 KPa, The resulted strain-time graphs were further treated mathematically to calculate viscosity of SSM billets. The interrelationships of viscosity, the microstructure and primary phase flow during compression are discussed, It is shown that the dendritic primary a-Al structure has the highest viscosity number which is almost three orders of magnitude greater than those for globular morphology, The current research have, for the first time, shown the validity and reliability of "parallel plate compression viscometry" method in characterizing microstructural evolution of Rheocast SSM billets.

Jan 1, 2005

By E. Barnard, J. Tero, J. Rajala, N. Avenido, M. Fullam, A. Nashitati, S. Mbalamba

"The Otjikoto mining and milling complex is 90% owned by B2Gold Corporation, and began commercial operation on February 28, 2015. The milling circuit operates at a throughput 3.3 million tonnes per annum, with an average reserve gold grade of 1.28 g/t. The ore is high in Gravity Recoverable Gold (GRG), which varies between 73-91%, depending on ore type. Overall gold recovery since start-up is 98.2%, with about 63.5 % coming from the gravity circuit as doré. 2016 cash operating costs, and all in sustaining cost (“AISC”) were $361 and $604 per ounce, respectively.During design, three ore types were tested for GRG content, and based on the high GRG value of all three ore types, the decision was made to treat the full ball mill circulating load by gravity. Once operating, the gravity circuit performance was characterized by performing a detailed gravity audit, which included the ore, cyclone classification, Knelson concentrators, and the Consep Acacia intensive leach system. The deeper ores contain significant pyrrhotite, and this created some unusual challenges that had to be overcome. This paper presents the gravity circuit design process, the circuit commissioning, and the audit results and ongoing improvements.IntroductionHeadquartered in Vancouver, Canada, B2Gold Corp. was founded in 2007. Currently, B2Gold has five operating mines, and numerous exploration projects in various countries, including Nicaragua, the Philippines, Namibia, Mali and Burkina Faso. The Otjikoto Mine is located in the north-central part of the Republic of Namibia. It is situated approximately 300 kilometers north of Windhoek, the country’s capital, within the Province of Otjozondjupa. The Otjikoto mining and milling complex is 90% owned by B2Gold Corporation, and began commercial operation on February 28, 2015. The milling circuit operates at a throughput 3.3 million tonnes per annum. During design, a large emphasis was placed on gravity recovery, as the Otjikoto ores are unusually high in Gravity Recoverable Gold (GRG)."

Jan 1, 2018

By C S. Beals

The Dominion Observatory was founded in 1905 and, from the beginning, it work included research in both astronomical and geophysical science. During its first years, up to 1916, the Observatory also included geodetic surveying as part of it scientific program. Although, at the beginning of the century, geophysics did not have the close connection with mineral exploration that it now holds , the founders of the Observatory were men of vision, and they laid a solid foundation for the application of the techniques of geomagnetism, gravity and seismology to an understanding of the Canadian terrain of plain , mountains, seacoasts and shield area . The particular sphere which the Observatory occupies in the field of geophysics has been evolving over a period of many years and it has now a rather definite relation to the work of other government bodies, university science departments and industrial organizations. We have, for example, an over-all responsibility for the regional magnetic mapping of Canada and, as the magnetic field is subject to slow but steady changes, we produce new magnetic maps of the country every five years. These maps indicate the strength and direction of the magnetic field, the variation of the compass and the rate of change of the magnetic elements.

Jan 1, 1963

By V. A. Preto

The Rexspar uranium deposit is located approximately 5 kilometres south of Birch Island, B.C. Three separate zones of commercial-grade uranium mineralization mineable by open pit have been outlined. Uranium and fluorite-celestite mineralization occur in a trachytic member of alkali-feldspar porphyry, lithic tuff, tuff breccias and pyritic schist conformably interlayered with a succession of strongly deformed greenschists and fragmental rocks that are, in large part at least, of volcanic origin. The age of these strata is not precisely known, but they are considered as part of the possibly Mississippian Eagle Bay Formation. Commercial-grade uranium mineralization is always associated with fluorphlogopite-pyrite replacement of the trachytic unit and is contiguous to, but separate from , a zone of ore-grade fluorite mineralization. In all zones, ore occurs in lenses of variable thickness and lateral extent, which lie parallel to the schistosity of the trachytic rocks and surrounding greenschists. The principal radioactive minerals at Rexspar have been identified by other workers as uraninite, uranothorite, bastnaesite, torbernite and metatorbernite. Considerable amounts of thorium oxide and widespread rare earths have been reported from all three radioactive zones. The geology of the deposit suggests that the trachytic rocks represent a highly differentiated intrusive-extrusive system in which fluorphlogopite, pyrite, fluorite and uranium-bearing minerals were deposited late in the evolution of the system by deuteric, volatile-rich fluids. The considerable amounts of thorium and widespread rare earths associated with the uranium tend to support the thesis that this element is of primary origin rather than secondary.

Jan 1, 1978

By V. Polotski

Initiated and financed by the Canadian Space Agency, Micro-Rover Platform with Tooling Arm (MRPTA) project has targeted the development of a robotic system with remote control and autonomous navigation capabilities for testing a large variety of analogous planetary missions. Although developed for planetary exploration, the navigation system is highly suitable to such areas of application as construction and in mining. Autonomous navigation system is capable of moving the platform to predefined position(s)/orientation(s) while continuously mapping the terrain, assessing its traversability and choosing most appropriate path to follow. Designed according to the JAUS (Joint Architecture for Unmanned Systems) framework, the system consists of several interconnected components. Following components are of particular importance: Pose Estimator (PE), Terrain Evaluator (TE), Map Manager (MP), and Path Planner (PP). The PE uses a minimal sensor configuration consisting of an azimuth gyroscope, inclinometer and wheel odometry. The PE provides reliable pose estimates in spite of pronounced slippage by employing extensive use of fused data. The TE uses a nodding laser scanner which continuously sweeps the area in front of the platform and constructs a ?traversability grid? (TG) of the surrounding area. Multiple TGs are constantly constructed along the platform motion path are combined into a terrain map maintained by the MP. The PP uses this map to compute a motion path Obtained path is executed by the motion controller and remains current until it is contradicted by the most recent map ? at which point it is re-planned. This paper addresses integration issues, lessons learned and also outlines the possible applications for construction and mining.

Aug 1, 2013

By J. K. Shaw

The science of low temperature engineering is well entrenched in mining. Uses for common cryogens, including liquid oxygen (LOX), liquid nitrogen (LN2), and liquefied natural gas (LNG) in the gas and minerals industries are reviewed. Potential future applications are discussed within the scope of mining, particularly in refrigeration and ventilation. The second part of this paper focuses on the Linde cycle, which is at the heart of most liquefaction plants. Steady state equations describing the mass and energy flows are presented. The paper concludes by explaining the concept of a wind powered Linde- Hampson cryogenic cycle and assessing, with scoping calculations, the technological feasibility of producing cryogens with an intermittent source of (renewable) energy.

Aug 1, 2013

By M. B. Greyver

The results of laboratory tests on iron precipitation from non-decopperized nickel anolyte are discussed. The parameters (pH, oxygen consumption and stirring speed) for iron precipitation from the anolyte, using the oxygen in the air, were determined. In the experiments conducted under optimized conditions, the residual concentration of iron in the anolyte after precipitation was 0.7-2.7 mg/L, and the copper and nickel losses to the solid phase were 0.05-0.07% and 0.05-0.16%, respectively. The filtration ability of the iron slurry obtained was 2 to 5 times higher as compared to that after chlorine oxidation and oxyhydrolysis. The leaching of the non-ferrous metals from the iron cake made using the separate nickel anolyte purification process was possible by dissolution in sulphuric acid. It was established that after cobalt precipitation from the copper- and iron-depleted anolyte, the precipitates obtained had lower ratios of Fe:Co and Ni:Co.

Jan 1, 2006

By D. G. E. Kerfoot

In September 1945, when the Lynn Lake nickel orebody was discovered Sherritt Gordon Mines was a small copper mining company with rapidly depleting ore reserves at its single producing mine at Sherridon in the Cold Lake area of Manitoba, 100 miles north of The Pas. The company has been formed in 1927, largely through the efforts of Eldon L. Brown, a 27-year old mining engineer, with the financial backing of Thayer and Halstead Lindsley and the Gordon family. The Lindsleys were American mine promoters who had been successful in the Sudbury area, and the Gordons had extensive interests in the lumber industry in northern Ontario. Carl Sherritt, who gave his name to the company, was an American trapper and prospector who had staked the copper property and sold his interest to the new company. Carl Sherritt died in a flying accident at The Pas in 1928. The Sherritt Gordon Mine started production in 1931, shipping copper concentrate to the new Hudson Bay copper smelter at Flin Flon, Manitoba. In 1931 the price of copper was 18¢/lb. Within a year the price had fallen to 5¢ /lb and the mine was forced to close. It remained closed through the Depression years.

Jan 1, 1999

By T. R. Eger

Miners can be exposed to whole-body vibration (WBV), when sitting or standing to operate mobile equipment. In order to prevent vibration-induced injury it is important to understand how miners can be exposed to vibration, the health risks associated with vibration exposure, methods to evaluate vibration exposure, and strategies to reduce vibration exposure. WBV exposure typically occurs when operating mobile equipment, such as a load-haul-dump vehicle, haulage truck, or dozer. The probability of health effects such as low back pain, neck pain, headaches, and gastrointestinal track problems occurring from daily vibration exposure can be determined based on criterion values published in ISO 2631-1 and EU Directive 2002/44/EC. A special case of WBV termed foot-transmitted vibration (FTV) occurs when a miner is exposed to vibration that travels through the feet. FTV typically occurs when standing on vibrating surfaces associated with the operation of locomotives, jumbo drills, bolters, or raise platforms; however, there is no set standard to evaluate health effects associated with FTV. Recent medical evidence confirms workers exposed to FTV can develop cold induced blanching of the toes, in addition to numbness and tingling in the feet and toes. In order to reduce the risk of adverse health effects from exposure to vibration, the hierarchy of controls (elimination; substitution; engineering; administration; and personal protective equipment) should be followed. Best practices should be used to minimize vibration exposure through equipment purchases (i.e. vehicles with lower vibration emissions and seats that attenuate vibration), reduced driving speeds, and improved road maintenance for example. The elimination of other risk factors, which increase injury risk when combined with WBV exposure, such as awkward working postures, should also be eliminated. Very little is known about FTV exposure therefore further research is required in order to develop exposure standards and identify prevention strategies.

Aug 1, 2013