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By Dallas W. Davis

Twin - Kennecott Deal Announced April 15, 2004 ! Kennecott earns 56% interest, if in 4 years, spends C$10 million and recovers at least 200 cts of +1 mm diamonds in all dimensions from any contiguous body ! Earn-in can take up to 6 years, but incurs stepped reduction of interest from 56% to 46% or 0% if $C10 and 200 carats not achieved ! By funding all costs through feasibility study, Kennecott earns 71% in 7 years, or, stepped reduction to 62% if completed after 8 years ! By achieving production within 10 years and funding Twin?s share of development and construction costs, Kennecott earns further 4% ! If no election to develop a mine within 2 years of feasibility study completion, Twin may present development proposal which Kennecott has 60 days to elect to follow or transfer management to Twin and dilute to 49% ! Each party has one time right to elect to market its diamond share ! On signing and annually, Kennecott will purchase $C250,000 of Twin shares at 130% of then prevailing market price until achieved earn-in

May 1, 2004

By K. Awuah-Offei

Long-term production scheduling optimization has been a challenging issue for the mining industry because of the size and complexity of the problem. The current planning algorithms have limitations in terms of addressing the stochastic variables underlying the mine planning problem. In this paper, an intelligent agent-based mine planning framework based on reinforcement learning is introduced. The long-term mine planning is modelled as a dynamic decision network. The intelligent agent interacts with the block model by means of a stochastic simulation and employs a Q-learning algorithm to learn the sequence of pushbacks that maximizes the net present value of the mining operation. The intelligent open pit simulator (IOPS) was implemented with an object-oriented design in Java®. A comparative application case study was carried out to verify and validate the models. The proposed method was used in planning an iron ore deposit and the results were compared to the Milawa scheduler used in Whittle® software. The outcome of the study demonstrates that the intelligent agent framework provides a powerful basis for addressing real-size open pit mine planning problems.

Jan 1, 2008

By Konstantinos Modis

According to recently established theoretical analysis and under certain conditions, a critical sampling density can be determined for an earth-related space-distributed natural variable. Sampling above this critical limit adds little to the mapping results. The objective of this paper is the application of the above theory to the Sesklo clay quarry in Greece, where Heracles General Cement Company had conducted a sampling campaign to estimate its reserves. The structural analysis of Al2O3 values generated a variogram model, from which the critical sampling density was identified. This critical number was by far lower than the existing sampling density. Clay reserves were then estimated using geostatistics and inverse distance squares in different data schemes with variable densities. The results of the comparisons between the various models revealed that, when the sampling density was greater than its critical value, geostatistics and deterministic interpolation gave similar estimations, which is also in agreement to the theory. The optimal sampling grid finally proposed here, will result to significant cost savings in the next drilling program which is now in plan by the company.

Oct 1, 2009

By L. Li

The rock quality designation (RQD) was initially introduced by Deere (1963) for civil engineering. But, its application has been largely extended to rock mechanics and has become a fundamental parameter in geotechnical engineering (e.g., Hoek & Brown 1980; Milne et al. 1998). The success of this definition is due, in great part, to its simplicity. However, this index includes a number of limitations. Among these limitations, a critical one is associated with the arbitrarily selected threshold value (e.g., Priest & Hudson 1976). Consequently, the RQD value would vary with different threshold length for the same core. Also, using the customarily and universally adopted but very arbitrarily selected threshold value of 10 cm (for NX cores) in the assessment of RQD, the RQD values usually tend to be either high or low in most rock engineering. Some intermediate values (50%) are less frequently encountered (Harrison 1999). The original definition of RQD does not well represent the actual quality of rock masses. In this paper, an improved definition of rock quality designation (RQDc) is given.

May 1, 2009

By Ian Bruce

Tailings and water management facilities are essential and integral components of mine and mill operations. They must be managed for the long term in order to ensure that safe and environmentally responsible stewardship is achieved. Toward this end, in 1998, The Mining Association of Canada (MAC) published A Guide to the Management of Tailings Facilities, which recommended the implementation of a tailings management framework (Figure 1) to integrate environmental and safety considerations into each stage of the life cycle of a tailings facility, from initial site selection and design, through construction and operation, to eventual decommissioning and closure. By February 2000 it was becoming apparent that while mining companies were making significant progress toward implementing and documenting tailings management systems, and integrating them with overall environmental management systems, further effort was warranted in their application at the operational level. In particular, a need was identified for further guidance in preparing manuals that outline procedures for the safe operation, maintenance and surveillance (OMS) of tailings and water management facilities.

May 1, 2002

By T. Gerritsen, R. MacRosty, R. Pula

For several years Hatch has been installing fibre optic temperature sensors on the copper cooling elements of smelting furnaces to improve monitoring capabilities in critical locations. The metal/matte tapblock is a key area to monitor in the furnace as it undergoes severe wear from the molten material repeatedly drained through it. The high wear rate around the tapblock means downtime is necessary to perform refractory repairs. A good understanding of the tapblock condition allows the operation to maximize safety and production; consequently the metal/matte tapblocks have been the focus of this study. Fibre optic technology allows the installation of numerous sensors in locations that are very sensitive to refractory thickness, thereby providing information previously unavailable with traditional measurements. The transient nature of the thermal response to tapping and the three-dimensional geometry of the tapblock confound the interpretation of refractory thickness from temperature measurements. This paper focuses on the analysis of both plant data and thermal modelling simulations and details the progress made in relating the temperature measurements to the refractory thickness in front of the copper tapblock.

Jan 1, 2014

By K. Morikawa, K. Asano, J. Yoshitomi

The quality requirements for ladle shrouds have become stricter year by year to the pursuit of higher productivity and improved quality in the continuous casting of steel. The ladle shrouds must be sufficiently durable under severe conditions, such as operation without preheating and during several sequential castings. The consideration is that ceramic fibres, which have been applied in shrouds for thermal insulation during casting, could pose a risk to the worker's health. We realized materials for the ladle shrouds which show high strength and low elasticity. At the same time pursuing effective insulation, a coating which contains no fibres (Foaming Coat) has been developed, replacing the conventional one containing fibres. These materials are durable under conditions of repetitive use and consequently satisfy the customer's demands. The ladle shrouds which were improved in this way have achieved an excellent durable life in hot service of three times that of conventional ones. This paper reports the recent technological developments in ladle shrouds as well as their performance under hot operating conditions.

Jan 1, 2004

By Douglas E. Wolfe, Jogender Singh, Robert Miller, Dong-Ming Zhu, Jeff Eldridge

This paper discusses microstructural changes produced by two novel approaches using electron beam physical vapor deposition (EB-PVD) in which periodic strain fields/microporosity was incorporated within the large columnar grains of Zr02- 8wt.%Y2O3 (8YSZ). The traditional columnar microstructure of partially stabilized zirconia has been slightly modified to produce a lower thermal conductive thermal barrier coating (TBC) by periodically interrupting the condensing vapor resulting in microstructural modifications with diffuse or sharp interfaces and morphological changes on the sub-micron scale without changing the composition of the TBC. These microstructural modifications resulted in a 20-30% reduction in the thermal conductivity, 28-56% increase in hemispherical reflectance, improved oxidation cyclic life (over 100%), and better strain tolerance as compared to standard ZrO2-8wt.%Y2O3 deposited on platinum-nickel-aluminide and CoNiCrA1Y bond-coated MAR-M-247 test samples. The TBC with tailored microstructures were examined by various techniques including scanning electron microscopy (SEM), x-ray diffraction (XRD), steady-state laser heat flux technique, and hemispherical reflectance.

Jan 1, 2004

By T. Cutard, E. Yeugo Fogaing, C. Gault, H. Marzagui, N. Prompt, M. Huger, C. Deteuf

This paper deals with studies made in the field of the French research network PROMETHEREF. Several refractory castables are considered in this program. In the present paper, one of these materials is considered, it is a low cement castable based on andalusite aggregates. A particular attention is paid to microstructural changes during the first heating and on their effects on the high temperature mechanical behavior. Microstructural evolutions have been characterized by the way of dilatometry, scanning electron microcopy and X-ray diffraction. In-situ observations by environmental scanning electron microscopy gave complementary results on these high temperature microstructural changes. They deal with microcrack formation, phase changes, crystallization, liquid phase formation and sintering. By propagation of ultrasonic waves, high temperature continuous measurements of the Young's modulus have been made. Results confirm the existence of microstructural changes and allow to quantify the Young's modulus variations all along specific thermal cycles. High temperature four point bending tests and room temperature tensile tests were made in the same temperature range. Behavior evolutions could be found and interpreted with the help of previously mentioned results.

Jan 1, 2004

By G. M. Ross, I. M. Ross, J. A. Scott

"The otherwise waste heat in many water streams in the mining industry can be used to provide space heating of adjacent infrastructure including laboratories, workshops, and offices. This can be achieved by using heat pump systems, which can work as a replacement or in conjunction with existing space heating. In the example investigated—process cooling streams at an ore smelter—the analysis provided illustrates that annual heating costs can be 19% lower and a simultaneous 62% reduction in CO2 emissions can be achieved.RÉSUMÉ Dans l’industrie minière, la chaleur qui serait normalement perdue des circuits d’eau pourrait servir à chauffer des structures adjacentes incluant les laboratoires, les ateliers et les bureaux. Cela pourrait se faire en utilisant des systèmes de thermopompes, qui pourraient remplacer ou s’ajouter au chauffage existant. Dans l’exemple étudié, des circuits de refroidissement de procédé à une fonderie, l’analyse fournie illustre qu’il est possible de réduire les coûts annuels de chauffage de 19 % et d’obtenir une réduction simultanée de 62 % des émissions de CO2."

Jan 1, 2016

By K. D. A. Whaley

The Captain North Extension deposit consists of five sulfide lenses hosted in cherty and chloritic metasediment that is bounded by quartz-eye rhyolite and laminated rhyolite. Lens 2 consists of sphalerite and galena with silver-rich tetrahedrite in chert. Lens 3 contains massive pyrite, with chalcopyrite and minor gold, gradational to minor pyrite in a chloritic metasediment. The other lenses are unexplored. The sulfides occur as beds, fracture infills, and disseminated grains. Reserves are estimated at 207 555 tonnes grading 7.380/0 Zn, 2.76% Pb, and 91.81 g/t Ag. The deposit is isoclinally folded, dips steeply west, plunges 50 degrees south, and is faulted out to the north, where drag folding has reversed the plunge. Minor cross-faults contain talc and sericite. High sphalerite but low pyrite abundances result in poor responses to standard electromagnetic techniques. Lens 3, which contains more pyrite than Lens 2, responds better to induced polarization and allows detection. Geochemical anomalies are found in a nearby swamp and stream, but an impervious till cover inhibits the development of soil anomalies.

Jan 1, 1992

By P. R. A. Andrews

"The sillimanite group minerals, kyanite, sillimanite and andalusite are identified as alumino-silicate minerals with the common chemical composition AIP3.Si02' so that each possesses similar physical properties. Kyanite is the most abundant mineral and mainly occurs in Quebec, Ontario and British Columbia; sillimanite occurs in Ontario and Manitoba; and andalusite in Nova Scotia. The main use for the sillimanite-group minerals is in refractory applications for the production of refractory bricks and shapes. In refractory applications, the main performance criterion is the relative percentage of mullite formed within the material during firing. This phase gives a greater degree of resistance to creep deformation and slag attack, and improves the ability of the refractory to withstand high temperatures under load. The beneficiation of refractory silicate minerals has been the subject of many investigations at CANMET, and the former Mines Branch. Eighteen kyanite, two sillimanite, and three andalusite evaluation studies were conducted between 1933 and 1987. A review of some of the more important studies is presented, which includes information concerning mineralogy, beneficiation methods and flotation data."

Jan 1, 1995

By Juan C. Sotomayor Álvarez

The Huantajalla mine is seated on Uchucchacua 's Mixing District that is the fourth producer of Silver in the world. Huantajalla Mine is a new mine that nowadays is being explored and recently it has began to operate. The project for 4-A vein exploitation in Huantajalla Mine using Longhole drillings as a new method of mixing is developed by Planning Department of Uchucchacua Mine in coordination with Geology Department of this mine, started in June 2004. This project is funded by Company of Mines Buenaventura S.A.A In July 2002, Geology Department started the exploration on the area of Huantajalla Mine, discovering the 4-A vein. The reconnaissance and definition of the vein finished June 2003, finding 79,080 Ton of mineral of Silver with a grade of 40.0 Oz Ag/ton and a thickness of 1.85 meters (6 feet ). Using the longhole method on the vein exploitation will replace the cut and fill and shrinkage methods, and it will keep a dilution of 15%.

Oct 1, 2004

By J .. R. Dalton

"Blasting in high sulphide content ores presents at least two major safety considerations: (1) compatibility of the explosives with the ore while resident in the borehole; and (2) introduction of a flame and shock producing explosive into this environment, while minimizing the risk of reactive ignition in the chemical reaction products/sulphide dust cloud resulting from the detonation. This paper will discuss only the second consideration, i.e. post detonation reactivity.The ETI (Explosives Technologies International) Technical organization, in consultation with the U.S. Bureau of Mines, reasoned that the most relevant considerations in the development of an explosive for this application are:• minimization of reactive gaseous detonation reaction products;• flame duration reduction;• flame temperature reduction;• increased explosive sensitivity;• reduced probability of ""low order"" detonation; and• maintenance of energy level as high as possible.Obviously, not all of these are totally independent properties, i.e. increased sensitivity will reduce the probability oj low order detonation as will higher energy levels. However, these considerations were examined separately as if they were independent."

Jan 1, 1994

By Å. Partapuoli, M. Henriksson, P. Wikström, J. Worth, G. Adolfsson

The control of AG mills fed by ores with harder and softer components can be challenging due to the sensitivity of the mill to the ratio of hard to soft components. The mills at LKAB’s iron ore operations are generally well controlled, but there are periods when the throughput falls off dramatically, due to a loss of mill filling. As the ore is upgraded in the sorting plant through magnetic separation prior to milling, this presents an opportunity to manipulate the feed blend in advance. In order to assess this opportunity, a fullscale mill charge was dumped and assayed by size to quantify the build-up of competent waste in the mills. This was supplemented by pilot and locked-cycle laboratory tests at a wide range of feed blends in order to facilitate the development of an appropriate multi-component AG mill model. This paper reports the experimental campaign requirements and methodologies, as well as the major outcomes from analysis and modelling exercises using the industrial, pilot and laboratory multi-component data.

Jan 1, 2012

By Bennett McLaughlin, Gille Brousseau, John F. Cook

"La Mine Bousquet commenced operations in October 1979. Mining has been by underground methods from two main zones which dip steeply to the south , Sub-level stoping methods with following fill are used.The orebody and immediate country rocks are sericitic and highly schistose. The intensity of schistosity varies significantly and poor ground conditions prevail, especially within the orebody,Initially few mining problems were encountered but in May 1981, significant damage occurred. A system of stabilizing pillars was introduced with improved support systems. Predevelopment in ore and pre-drilling of blastholes were reduced with extra footwall development.Damage has continued to occur on a regular basis particularly during the spring thaw. Generally, the adverse conditions have been successfully overcome.IntroductionMost of the mining problems that have been experienced at Bousquet have been caused by poor ground conditions . This pa per describes these conditions, considers the cause and describes the ways in which the conditions have been dealt with . Despite the problems, Bousquet is a successful operation which in 1983 produced 95,000 ozs of gold from 514,000 tons of ore."

Jan 1, 1985

By D. A. Mackie, J. E. Rider

"Good belt conveyor design is the most often neglected detail in the engineering of a plant. This results in downtime from spills or jams and premature failure of equipment components. Careful layout and component selection will result in better operation, a cleaner plant and therefore lower maintenance costs.IntroductionDespite the availability of many excellent sources of data on conveyor design, such as the Conveyor Equipment Manufacturers' Association (CEMA) Manual, ""Belt Convyors for Bulk Materials"" , there continues to be repetitive errors made in design. Why? Certainly, there is no substitute for experience, but largely, classical errors in belt conveyor design is rather elementary and so the temptation to have the work done by relatively inexperienced designers is great. What that does is develop "" experienced"" designers who become incompetent through no fault of their own. It is hoped that this paper will supplement available design data, help those who are "" put into"" a design situation to better cope with their predicament, and ease the lives of plant maintenance personnel."

Jan 1, 1990

By W. F. Giuvlore, E. Mcroberts, T. S. Golosinski

"The rising demand for Canadian coal and depletion of shallow deposits, most suitable for surface mining, result in rapidly increasing volume of waste materials which have to be moved by the coal mining industry. While at present this challenge is being successfully met using conventional mining methods, in the future, innovative methods must be considered if Canadian coal is to remain competitive.The need for more efficient mining methods is also faced by the oil sands industry to assure competitiveness of the synthetic oil price.A look at the world mining practice indicates that large volumes of material can be economically mined and moved by the continuous mining systems comprising bucket-wheel excavators, belt conveyors and stackers. To assess the state of art and applicability of this mining method to Canadian conditions, the field trip was organized by the Department of Mining Engineering o f the University of Alberta, to several typical mining operations in Europe. It is in Europe where the continuous mining methods were developed and are almost exclusively used in large-scale surface mining."

Jan 1, 1984

By Holly L. O. Huyck

Disseminated hypogene sulphide mineralization in the Lakeshore porphyry copper deposit (also called the Cyprus-Casa Grande deposit) of Arizona occurs in both a granodiorite stock and associated volcanic rocks. Structural development and vein paragenesis at Lakeshore are similar to other Laramide porphyry copper deposits of the southwestern U.S. Two major structural trends are present: intrusive contacts, copper-bearing potassic alteration veins and major post-mineralization Basin-and-Range type faults trend N-NW, whereas phyllic veins and secondary post-mineralization faults trend N-NE, and deep propylitic veins trend NE-ENE. Lithologic permeabilities, caused by fracturing in all rocks and by grain size distributions in volcanic rocks, controlled the distribution of copper mineralization. Differences in chemical compositions of host rocks did not affect are grade. Structural control, through density of chalcopyrite-rich veins, was the major control of are grade. Fracture density of other potassic vein types did not strongly affect grade. Within volcanic lithologies, permeability, as indicated by grain size distribution, provided a second-order, but significant, control of mineralization.

Jan 1, 1990

By Robert B. Parsons

"Finance Minister Paul Martin's second budget might be good for Canada's mining industry in the long run, but the budget raises a number of concerns for the industry in the near term. The budget papers suggest that the 25% resource allowance is not working as intended, and report that the Department of Finance will be reviewing this valuable allowance. The so-called ""large corporations tax"" rate will be increased. This annual tax, which is imposed on a corporation's capital even when the corporation is not in production, is particularly harmful to the mining sector.IntroductionThe Honourable Paul Martin, in his second federal budget, emphasized spending cuts and made only modest tax changes. However, two of these tax changes could have a serious impact on the Canadian mining industry: the proposed review of the 25% resource allowance; and, the increase in the large corporations tax rate.Personal Tax Measures Personal Tax Rates UnchangedThe government has been under political pressure not to increase personal tax rates. Mr. Martin's announcement that rates would not change will be popular."

Jan 1, 1995