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By J. Peterson, D. D. Tannant, J. Todd

"A review of blast designs and improved blasting practices at the EkatiTM diamond mine is presented along with the results of three blast-monitoring experiments. Blast monitoring was undertaken to investigate blast damage mechanisms in the mine’s well jointed rock mass. Rock mass damage caused by production, pre-shear and wall control blasts was measured. EkatiTM uses 270 mm holes for production blasting, and 165 mm holes loaded with a decoupled charge for pre-shearing. The production blasts are loaded with bulk emulsion/ANFO blends. The mine plan involves using 30 m double benches. A 30 m high pre-shear is drilled and blasted prior to the production blasting that is done with sequential 15 m benches. This paper summarizes the monitoring equipment and data gathered to date. IntroductionThe EkatiTM diamond mine is located about 300 km northeast of Yellowknife, Northwest Territories, Canada. The mine is a joint venture of BHP Diamonds Inc. (80%) and geologists Charles Fipke and Stewart Blusson (10% each). The EkatiTM mine is Canada’s first diamond mine and BHP is the operator. The mine is accessed by air and by a winter ice road.The first kimberlite pipe mined at EkatiTM is known as the Panda pipe. The Panda open pit mine will have a total depth of 315 m (Fig. 1), a width of about 600 m, and a 50° overall slope. Initial ore production is 9000 tonnes per day.This paper summarizes the pre-strip blasting and the evolution of the production and wall control blast designs from 1997 to 2000. The initial blast designs and the rationale behind subsequent changes that took place are presented along with the techniques currently in use.The paper also briefly presents an experiment done to measure the rock mass response to blasting. Three blasts were instrumented with geophones, gas pressure sensors and time domain reflectometry cables. A brief summary of the instrumentation and data gathered is included."

Jan 1, 2001

By Fabian Mohr

The methyl substituted binuclear cyclometallated gold(I) complexes [Au2(?-n-MeC6H3PPh2)2] [n = 4, 5 and 6] all undergo oxidative addition reactions with halogens and, in the case of the 4- and 5-methyl substituted analogues, with dibenzoyl peroxide to give metal-metal bonded digold(II) complexes [Au2X2(?-C6H3-n-MePPh2)2]. The 4- and 5-methyl substituted digold(II) compounds on warming or exposure to light undergo carbon-carbon coupling reactions to give gold(I) complexes containing the corresponding 2,2'-n,n'-biphenylyldiphenylphosphines. The 6- methyl substituted digold(II) complexes rapidly isomerise above ca. -20° C to binuclear heterovalent gold(I)/gold(III) compounds [XAu(?-2-Ph2PC6H3-6-Me)AuX{?2-(6-MeC6H3-2-PPh2)}], containing a fourmembered cyclometallated ring on a gold(III) centre. Surprisingly, no carbon-carbon coupling could be induced for any of the 6-methyl substituted compounds, even under forcing conditions. This difference in reactivity of the 6- methyl derivative, compared to that of the 5-methyl and unsubstituted analogues was studied by ab initio calculations using a series of model compounds. The results are in excellent agreement with the experimental findings and suggest that the key-step in the C-C coupling reaction is the partial opening of the Au(III)-P bond in one of the transition states. In the 6-methyl system this transition state is energetically inaccessible and hence no C-C coupling occurs.

Oct 1, 2003

By W. Leblanc, J. Phalen

This paper tells the story of a serious mine fire on a mechanized longwall face in a submarine coal mine at Glace Bay, Nova Scotia. The story gives, in chronological order, a technical account of the steps taken to investigate, fight and contain the fire. The time during which the events took place spans from June 19 to November 7, 1975.

Jan 1, 1976

By A. Y. Senchenko, Y. V. Kulikov

"Different methods aiming at specific energy calculation and design of AG/SAG circuits are used in mining. They include JK DWT/SMC test, SAGDesign test and CWi/RWi/BWi tests. The simplest methods with no secret equations and giving energy required for grinding in kWh/t were proposed by F.?. Bond and J.H. Starkey. D.J. Barratt proposed to use results of CWi/RWi/BWi tests for AG/SAG mill sizing. The present paper gives an alternative for forecast of specific AG/SAG energy. The principle is similar to the theory proposed earlier and consists in cumulative AG/SAG energy calculation using indices of rod and ball grinding (RWi+BWi) without impact crushing index (CWi). Then total energy is divided between two grinding stages using special formulas based on extensive statistical information. The forecast indices of AG/SAG and ball grinding are similar to the SAGDesign testing results. Hereinafter the predicted indices are used for mill sizing of the whole grinding circuit. The method considered in the paper enables prediction of AG/SAG energy based on the test results according to Bond method. The proposed method version was not widely published earlier. The aim of the work was to elaborate cost-effective, reliable and accessible way to determine specific AG/SAG energy. At this stage of method development, it is recommended to use it only for works at preliminary Geometallurgy stage (Scoping, Pre-Feasibility). At design stage the obtained data should be confirmed by appropriate testing using alternative JK DWT/SMC and SAGDesign methods.INTRODUCTIONAppropriate crushing and grinding testing is required to design efficient comminution circuits. It is obviously important to obtain accurate information about ore hardness properties since the main energy consumption at the plant is associated with comminution processes. Moreover, it is required to apply the processes that make it possible to minimize operating costs and efficiently use capacity of the installed equipment installed.When studying ore hardness properties, it is required to take into account that breakage of the material is performed using different equipment. That is why accurate selection of the equipment and the circuit calculation without relevant testworks is impossible. Ideally, the testworks should provide answers to the following questions: determination of ore hardness properties, determination of specific energy consumption for comminution as well as obtaining of sufficient amount of statistically significant results from the tests. The results from crushability and grindability testworks in the first place provide assessment of ore hardness properties and in addition correlate with throughput of the respective equipment. The data obtained can be used for modeling of comminution circuits at the stage of the technology development"

Jan 1, 2016

By J. R. Goode

"Canada developed pioneering rare earth solvent extraction methods to recover the rare earths and thorium as by-products of uranium recovery operations in Elliot Lake, Ontario, and was a major supplier of these key elements from about 1960 until 1990. At one stage, Elliot Lake was supplying perhaps one third of the world’s yttrium as well as much of its thorium. This paper reviews the development of Canada’s early rare earth and thorium production facilities. INTRODUCTIONThe rare earths and thorium were first identified in the early 19th century but were little more than curiosities for the next century. However, in the mid-1960s the invention of rare earth-based phosphors for the cathode ray picture tube used in colour television sets launched a major demand for certain rare earths.The use of thorium as an alloying agent in aircraft and missiles grew rapidly in the late 1950s. In the same period, demand for uranium for both weapons and power production soared. Also in the late 1950s, the Elliot Lake uranium-thorium-rare earth deposits (also known as the Blind River deposits) were discovered. This conjugation of events led to uranium production in the Elliot Lake camp, quickly followed by the co-production of thorium and, later, the rare earths.Uranium production in the Elliot Lake camp continued from 1955 to 1996. Thorium was produced continuously from 1959 to 1969. Rare earths were produced, intermittently, from 1965 to 1990. Complete production records are not readily available but unquestionably Elliot Lake made a significant contribution to world thorium and the rare earth production. This paper, presented earlier in an abbreviated form (Goode, 2012), is intended to present as much of the information that is available."

Jan 1, 2012

By Robert C. Stanley

Early History Probably the first use of nickel by man was in the fashioning of implements, and later swords, from nickel-bearing meteorites, masses of metal that have fallen from time to time at many points on the earth's surface and which consist normally of iron carrying substantial amounts of nickel. Meteorites were perhaps the first metal known to man. The falling star, sought out with fear overborne by curiosity, was found to be a better stone than the earth-given, truly a boon from the gods. Archeologists tell us there is good evidence that the ancient oriental peoples learned at an early date to make these stones into useful implements. The invincible blades of the great warriors of old in China, Persia, and in northern Europe, were Heaven-sent, a fable which sounds significant of meteoric iron. Probably some of the ancient swords of Khorassan and of Damascus were of meteoric nickel-bearing iron (1). Fifty centuries were to pass before men learned to isolate nickel and add it to iron to produce the same alloy for much the same purpose. Meanwhile, man had found another natural alloy of nickel, known first to the Chinese as paktong, or 'white copper.' It was obtained from complex copper-nickel sulphide ores of Yunnan in southern China. This metal was brought by caravan through India into Bactria, a country north of the Hindu-Kush mountains, in what is now known as Russian Turkestan. The earliest specimen extant is a Bactrian coin attributed to 235 B.C. The rough reddish-white metal was also sent in the form of triangular rings to Canton, where zinc ores were added and the whole smelted to a more malleable alloy, also known later as paktong. This alloy was the forerunner of German-or nickel-silver. Specimens of this alloy, wrought into ornamental candlesticks and boxes, were brought from Canton to Europe by the East India Company in the early days of the China trade. Paktong was highly prized for its beauty as well as its eastern origin in far-away China. By 1760 the unwrought metal was imported into England for domestic manufacture.

Jan 1, 1935

By S. Xu

Magnesium alloy AM50 is of interest to automotive cradle application because of it excellent castability and good ductility. In this work, microstructure and mechanical properties of both low pressure die cast (LPDC) and high pressure die cast (HPDC) AM50 test bars are characterized. Microstructure was examined using optical microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM). Phase identifications were performed using energy dispersive x-ray spectrometer (EDS) and TEM diffraction. It has been found that LPDC produces much coarser microstructure than HPDC. At the same time, the HPDC samples are more heterogeneous in microstructure and composition close to grain boundaries. Particles with various dimensions and morphologies of two different intermetallic phases, Mg17A112 and A18Mn5, were found in all the samples. Mechanical tests were performed under conditions similar to those related to an engine cradle application. LPDC samples show lower strength but better creep resistance than HPDC mainly due to the difference in grain sizes and grain boundary microstructure between LPDC and HPDC. Creep curves are well described by the empirical Andrade equation. Tensile-compressive yield and creep asymmetries were found in AM50, i.e. better deformation resistance in tension than in compression. The average yield asymmetry ratio for all the samples is 0.87. Microstructural examinations on the samples tested in tension, compression and creep showed that the deformation mechanisms in AM50 were slip plus twining at temperatures up to 125°C. The examinations indicate the important role of twining in the asymmetry phenomenon. The creep results indicate that dynamic precipitation of the Mg17A112 phase during testing is not the mechanism directly responsible for the creep asymmetry in AM50.

Jan 1, 2004

By A. Villanueva

The effect of High Pressure Grinding Rolls (HPGR), as a preceding stage to a conventional ball mill circuit at PT Freeport Indonesia?s C1/C2 concentrators, has been studied in terms of downstream grinding efficiency and circuit performance. When milling the product from the HPGR, mill capacity increased by 21% for the same product grind size, when compared to processing similar ore from a conventional crushing circuit. This achievement is a result of several reasons, among them: reduction in feed size (F80), fines generation beyond the proportional reduction in F80, reduction in ore hardness induced by HPGR comminution mechanism, optimization of the recycle system of the HPGR and ball string optimization in the ball mill circuit given the new feed to the mill.

Jan 1, 2012

By E. Fritz

This paper reviews the history, developments and 10 milestones of the oxygen steelmaking processes, with a special focus on conventional autothermic converters, high-speed converters with a blowing rate up to 5 m3n/t min and allothermic converters with coal addition, post combustion and the possibility to increase the scrap rate up to 50%. Related operating results are introduced. A new process route, which is based on hot metal and chromium ore, is outlined. The cost advantage for the production of 304 stainless steel grade is higher than 100 USS/t. The synthesis of EAF and oxygen converter steelmaking, a comparison of decarburization rates, refining combustion burners for optimized oxygen-management in EAF and an example for a large advanced EAF are outlined. Possibilities of flexible steelmaking and the growth and outlook of worldwide oxygen steelmaking are described.

Jan 1, 2004

By Charles A. Taschereau

Burkina Faso ? Formerly known as Upper Volta; Country is landlocked and dry (Sahel sub-Sahara zone); ? Among poorest countries in the World, according to the United Nations Human Development Index (in 2005, 178 out of 179 countries; in 2009 173 out of 179); ? Population 13,9 Millions; Life expectancy is 51.4 years; Fertility rate 6.47 children/woman; Average age is16 years; literacy rate 23.6% and GDP per capita $1,213; ? French is official language; Politically stable country; very low criminality rate; corruption level low. Multiparty elections since early 90s; Legal and political systembased on French civil law system; ? Country just opened a few years ago to International mining companies, with a new mining code and investment code; ? No experienced labour; ? All new codes and laws; no established practices; Very limited economic development, mining is already main product of exportation and the country will become with Essakane a mineral economy (over 50% of total exports from mineral sources);

May 1, 2010

By Laura Prati

Gold-on-carbon catalysts resulted very active and selective in liquid phase oxidation [1, 2, 3] and during past studies we established that activity is ruled by two factors: particle dimension and gold exposure on the carbon surface [4]. These two parameters are also connected to the nature of activated carbon where the chemical nature of the surface oxygenated groups probably plays an important role [5]. Our studies, focused on the design of an active gold-on-carbon catalyst for liquid phase application, were aimed, operating a fine tuning of all the parameters involved in determining activity, to optimize gold-on-carbon preparation, keeping in mind that gold particle activity increases with decreasing particle size and increasing gold exposure. Gold sol immobilisation represents a versatile methodology in preparing gold catalysts [6]: throughout this work we used as sol stabilizing agent, the N-dodecil-N,N-dimethyl-3-amino-1-propan sulphonate (SB), that provides both sterical and electrostatic stabilisation, a condition we already demonstrated necessary to preserve particle dimension when carbon is used as the support [6]. We generated different gold sols by varying the relative amount of reagents (HAuCl4, SB, NaBH4), the type of alkali and the temperature of the gold precursor reduction. Moreover, as we had recently evidenced that there is also a carbon effect [5], we employed only one active carbon to immobilize the sols.

Oct 1, 2003

By P. Klossek

It is estimated that China accounts for 94% of the world supply of rare earths (Roskill, 2011). This fact, together with the impact of China?s export policy, poses a substantial risk to the security of the rare earth supply as well as a rare earth price risk. This situation has motivated an increase in the number of rare earth projects under development, i.e., there are currently more than 440 worldwide (Technology Metals Research, 2012). However, economically and environmentally acceptable processing technology to produce tradable products from rare earths (e.g., separated rare earth oxides) is not freely available on the market at the moment. In this respect, a lot of research and development has been initiated on this topic, in academia as well as in industry. Using a proprietary model and scenario-based analysis, we studied the impact that the development of rare earth processing technologies would have on the rare earth market and the economic feasibility of rare earth projects mentioned before. The analysis showed that this impact varies depending on the technology type (e.g., technology can affect project production volume, cost structure or both) and the legal context of the invention (e.g., free or limited by patenting availability of a new technology). The effect of a technology which influences project production volume is not the same as of a technology which changes project cost structure. The impact of a patented processing technology differs from the impact of a processing technology which is freely available on the market. In the case of a new technology which is limited by patenting, its impact depends on the market position (?producing?, ?next-coming?, or ?not producing? project) of the patent holder. The paper contributes to existing research by studying the dependence of the expected micro- and macroeconomic impact of rare earth processing technology developments on the properties of a new technology (e.g., costs, legal framework etc.). By this means, the paper adds to existing knowledge and attempts to make the rare earths market more transparent and predictable from a perspective outside China.

Aug 1, 2013

By K. Yamaguchi

To contribute highly efficient and environmentally conscious copper smelting process, several topics in chemistry of the continuous converting were discussed. Through the reviewing the authors' thermodynamic simulations, it is recognized that small amount and low copper content of the coexisting slag is preferable. Some discussions were added to the Takeda's diagram for Cu20-FeOx-CaO ferrite slag, and the activity curves of the constituents were derived. Thermodynamic calculations were carried out on the copper contents of the slag during the blister copper formation. The dissolution of copper in slag decrease somewhat with increasing temperature, but the effects of increasing S02 pressure and decreasing %S in copper are considerable to increase in copper content of the slag. The optimum oxygen enrichment in the supplied air, and regulation of the oxidation degree for the blister copper are important in practice. The gypsum phase separation in the calcium ferrite slag was also evaluated thermodynamically, and concluded that decreasing temperature, increasing CaO content or S02 pressure, and extensive oxidation of the blister copper tend to separate CaS04.

Jan 1, 2007

By J. P. Cooney

Placer Dome is learning from experience in Latin America, Asia and Africa, as well as in North America, that contributing effectively to sustainable human progress in the areas of its operations presents unending challenges to think creatively, communicate effectively and remain culturally sensitive. People must be better off in terms of their economic circumstances, their social conditions and the quality of their natural environment not only during the life of the mines, but after mines close. Stakeholders, all those who are directly or indirectly affected by a mining project, should be able to participate in decisions which affect them. The development of sustainability strategies, the monitoring of sustainability performance and the implementation of sustainability programs are best done in partnerships with governments, communities, nongovernmental organizations and multilateral development institutions. Ultimately, the success, if not the survival of mining, will depend on our ability to get the sustainability equation correct.

Jan 1, 2000

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 Pierre Buteau

Peat/ands distribution in Canada is widely spread thoughout the country and corresponds to a wide spectrum of wetland habitats which overlay peat deposits. The development and the evolution ofpeat/ands and peat deposits are closely linked together, since the vegetal remains of the peat deposits originate from the peatland habitats, and the peatland habitats constitute a response to many factors, including the properties of the substrate, which are the peat deposits. Peat/ands are defined as waterlogged terrains where the production of plant materials usually exceeds the rate of decomposition. The underlying peat deposits consists of organic residues associated to peatland vegetation, more or less decomposed, built up and kept under anaerobic conditions. Peat/ands evolution and distribution are determined primarily by climatic factors, but also by the geomorphology and edaphic conditions. All of these create particular hydrodynamical environments which will vary according to different regional settings, and sequentially to an evolutive time frame.

Jan 1, 2001

By Robert B. Parsons

"Once all the hullabaloo about Finance Minister Wilson's April 27 budget died down (or was it an April 26 budget?), the pain of the budget papers began to sink in. Individuals and corporations will have to dig deeper and pay more taxes - and government will continue to dig deeper and spend more. The irony of the situation is that higher tax rates actually make flow-through shares more attractive as a tax-deferral investment - a bittersweet ""bravo"" for the mining industry.INTRODUCTIONFor the first time in Canadian history, a major budget address has taken two days to deliver. Of course, it's not a case of long-windedness, but rather a case of a hastily called press announcement on April 26 in response to a budget leak, followed by a formal budget speech on April 27.The general reaction of the business community to the budget was to the effect that the tax hikes are acceptable, but the government's failure to curb spending is less than acceptable. Mr. Wilson's reported response indicated that the government had never promised to cut spending, and that increased government spending would actually benefit the country. That age-old debate will doubtlessly continue for generations.In any event, three noteworthy components of the budget papers are:• Personal income tax rates increase effective July I, 1989;• A ""large corporations tax"" (in effect 'a corporate ""minimum tax"") is effective July I, 1989; and• Federal sales tax increases are effective from June 30, 1989, to be replaced by a national sales tax in 1991.A brief overview of these and other budget proposals follows."

Jan 1, 1989

By T. B. Williams

A SEARCH of the records indicates that evidences of accumulations of petroleum and natural gas within the boundaries of British Columbia were discovered at approximately the same time as were those of Alberta. They probably would have been developed as soon bad it not been for the fact that they are in such uninhabited parts of the Province. Even today, the seeps of the Flathead area, and the later discovered extensive seeps of the Peace River area, have been seen by very few people. From the geological evidence, there is reason for believing that British Columbia soon will be a petroleum producing Province. Fifty-eight operators, both companies and individuals, are now backing the money and the effort which they have invested with us, for the most part within the last three years, in a belief that this is so. The promulgation of the Petroleum and Natural Gas Act in 1947 marked the beginning of a new phase with regard to the exploration and the development of our petroleum and natural gas resources. Since August 15th, 1947, the date on which the Act came into force, the area under exploration bas increased from a few thousand acres, held by lease under the Goal and Petroleum Act, 1986, to 10,460,115 acres, including all active permits, licences, and leases. In addition there are 192,720 acres under application, bringing the total under issue and application to 10,652,835 acres. The total area is comprised of 105 permits, 20 licences, and 26 leases under the 1986 Act. The permits and licences, which ?represent active exploration and development, are held by a total of 82 companies and 26 individuals.

Jan 1, 1951

By R. Tomás, J. B. Serón, M. Romana

The Slope Mass Rating (SMR; Romana, 1985) geomechanics classification was developed as a sequel of Bieniawski’s Rock Mass Rating (RMR) system, which was almost impossible to use in slopes due to the extreme range of the correction factors (up to 60 points of a maximum of 100) and to the lack of definition of them. A detailed quantitative definition of the correction factors is one of the advantages of SMR classification. During the last thirty years the use of SMR system has been extended to many countries from the five continents and, thus, it is time to review the most interesting developments. Both RMR and SMR are discrete classifications, depending on the values adopted by the variables that control the parameters. This can cause major changes in the parameters value due to small differences in the variables value, with changes in the final rock mass assigned quality. On the other hand, geomechanics quality indexes are extremely biased. To avoid this problem, some authors have proposed continuous functions for SMR. This classification has been also adapted for its application in heterogeneous and anisotropic rock masses, for high slopes, for is application trough stereographic projection and Geographical Information Systems, has been used as susceptibility rockfall parameters and has been included in the technical regulations of several countries. Additionally, some open access computer tools have been developed for the computation of SMR. Consequently, this paper reviews: 1) the most important modifications and adaptations of slope classifications which derive directly from SMR; 2) the use of SMR throughout the world; 3) many significant papers on slopes analysed with SMR all over the world; and 4) future trends in the use of SMR.

Jan 1, 2015

By Tom Demorest

SMART is an association of mining companies that meet regularly to coordinate the technology development needed by the mining industry. Since 1995, the member companies and institutions have directed research and influenced the manufacturers and suppliers to improve surface mining technology and services. SMART actively supports learning seminars, collaborative research projects, and user groups. Members of SMART include some of the major surface mining companies in North America and Australia. These companies have recognized the value that collaboration can bring to the needs of individual organizations as well as the global mining industry.

May 1, 2009