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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 Deni Côte, Michel Dagbert, Marcel Vallée

"Greater reliability of mineral deposit and reserve estimates can be attained through better quality control of the data and information acquisition, and the estimation processes. This paper reviews the following key requirements:1. greater awareness of the significant figures of both data and estimates, and better understanding of the probabilistic aspects of the estimates, their confidence limits and margins of error;2. greater reliability of the information that supports the estimates, by more explicit and more rigorous methods and standards for data acquisition and for interpretations;3. more quantitative estimations of geological/mineral continuity, based on improved three dimensional sampling patterns and the use of geostatistics; and 4. better integration at the project engineering and mine production stages, of the mineral deposit characteristics and mining method constraints, for more efficient mineral recovery and mine quality control.RÉSUMÉUne plus grande fiabilité des estimations des gisements et des réserves minières requiert plus d'emphase sur le contrôle de la qualité de I ‘acquisition de l'information et du processus d'estimation. Les exigences suivantes sont revues:1. le respect du niveau d'exactitude des données et des estimes en n'utilisant que le nombre approprie de chiffres significatifs des observations et mesures, et en exprimant le niveau de confiance et la marge d'erreur des estimations;2. l'amélioration de fa fiabilité des données par des normes plus rigoureuses pour leur acquisition et leur vérification, et par des méthodes plus systématiques d'interprétation et de modélisation;3. l'estimation plus rigoureuse de la continuité des minéralisations dans les trois dimensions des gisements, par des patrons échantillonnages mieux adaptes awe paramètres géologiquement minéralogiques, et par l'utilisation des méthodes géostatistiques; et4. l'intégration plus poussée, particulièrement lors de la planification de l'exploitation minière, des caractéristiques des gisements avec les contraintes des méthodes d'exploitation, pour améliorer la récupération et le contrôle de la qualité en exploitation."

Jan 1, 1993

By M. J. Dry, G. B. Harris

"This paper presents basic chemistry and operating conditions for the hydrolysis of ferric chloride into solid hematite and gaseous hydrogen chloride, and shows how this unit operation can be applied in chloride hydrometallurgy to regenerate strong hydrochloric acid and reject iron without also rejecting valuable metals such as nickel, copper and cobalt. Two examples are used to illustrate the hydrolysis technology and compare it to existing technology. The first is the regeneration of spent steel pickling acid, comparing hydrolysis to conventional pyrohydrolysis. The second example is the processing of a hypothetical low grade nickel laterite, comparing the novel chloride hydrolysis route to conventional sulphate HPAL technology.INTRODUCTION Whilst, in many respects, the control and removal of dissolved iron from chloride leach solutions can resemble the manner in which it is done in sulphate systems, chloride chemistry additionally offers the ability to achieve the same objectives in different ways (Harris, 2014). Conventionally, iron is oxidised to its ferric state (if necessary) and then precipitated with a base, usually magnesia where the feed is a laterite and lime where it is a sulphide, since calcium will precipitate sulphate formed during leaching. One method for controlling iron is to form FeOOH, either ß-FeOOH (akaganéite), a-FeOOH (goethite), or a mixture thereof (Fillipou and Choi, 2002). However, if akaganéite is formed, the precipitate will contain a significant chloride component (as high as 7% Cl), leading to chloride losses and difficulty in satisfactorily disposing of the residue. Washing chloride from akaganéite is almost impossible due to the propensity of the solids to undergo peptization. The conventional approach requires the addition of a base, but it is based to some extent on controlled supersaturation precipitation (Demopoulos, 2009), which produces a more uniform and crystalline material and is far more attractive than, for example, the turboaeration process proposed by Great Central Mines in their chloride copper process (Raudsepp & Beattie, 1986)."

Jan 1, 2016

By V. ?. Chanturiya, G. P. Dvoychenkova, ?. Ye. Kovalchuk

"Several mineralogical investigations have revealed the composition of modified kimberlites and the mud generated during treatment of diamonds, which contains up to 50% clay minerals (e.g., talc, talcsaponite, chlorite-saponite, Na-saponite) and X-ray amorphous phase. We investigated the composition of the natural diamond surface in relation to the diagnosed minerals and established the sequence and conditions for mineral formation on the crystal surface under kimberlite processing conditions. This article suggests a method to destroy and further dissolve minerals on the crystal surfaces using water system electrolysis products, which makes it possible to restore the diamond hydrophobic properties. The application of chemically treated water in the foam separation cycle under the conditions of high recovery of diamonds made it possible to increase the content of the factory concentrate by 8.0%.INTRODUCTIONThe high content of the modified minerals in the kimberlite ore results in the formation of hydrophilic slicks on the surface of the crystals which decreases the diamond’s hydrophobic properties and increases the losses thereof in the process of grease and foam separation to 20-30% (Kurenkov, 1957; Chanturiya et al., 1998, 1999, 2005; Duikarev et al., 2000).The previous researches have revealed the fact that the prospective way of solving the problem of intensity of mineral impurities formation on the surface of the crystals and the increase of concentration parameters is reached due to application of physical and chemical stimulation techniques on the solid and liquid pulp (Stricland-Constable, 1971; “Improvement of the technology…”, 2006; Makarskii, Adodin & Tarasova, 2011; Chanturiya, Dvoychenkova & Trofimova, 2012). However, the main task of investigations to stipulate the objective achievement is the studying and justification of the reasons of the diamond surfaces covering by the mineral slicks"

Jan 1, 2016

By J. Duriez, L. Scholtès, F. V. Donzé

"Fracture propagation process in brittle rock is investigated by means of numerical simulations performed with an adapted formulation of the discrete element method. The progressive failure mechanism is simulated through the breaking of the bonds making up the cohesion between the elements constituting the simulated medium. The use of appropriate contact laws associated to a near neighbor interaction feature provide the model the ability to reproduce fundamental characteristics of brittle rock behavior such as, for example, high values of the tensile to compressive strength ratio. Great attention is given to accurately describe the properties of the pre-existing joints or faults in the model. A specific joint model gives the possibility to define a tailor-made behavior of the discontinuity surfaces without suffering from discretization bias.Compression test simulations are performed on pre-flawed samples and compared to experimental results in order to validate the numerical approach for describing the initiation and propagation of fractures in brittle rock under mode I+II loading. It is shown that the crack mechanical parameters can greatly influence the fracturing pattern, in particular its frictional properties. Overall, the numerical simulations reproduce fairly well the failure patterns that are obtained experimentally.The discrete model is then used to study mode I+III loading to give an insight into fracturing problems occurring at the scale of the continental crust. The ability of the model to support mechanically the physical modelings performed with wet clay or sandbox is shown. As an example, the model is used to track the development of a twist crack system (wrench fault) through the nucleation and coalescence of microcracks."

Jan 1, 2015

By P. C. Garg

"IntroductionThe Central Mine Planning and Design Institute (CMPDI) of India, started planning the extraction of thick seams highly susceptible to heating in 1977by the French method of sub-level caving and/or multi-slicing. Nitrogen flushing was proposed for inhibition of heating by the author in one such project - the Kotadih colliery.Inhibition of heating was unheard of in the Indian coal industry before 1977-78. The usual practice was to seal off a district or a part of the mine or the entire mine when spontaneous heating occurred. With very little equipment in a normal bord and pillar district and a low production rate, the financial loss in capital assets and in production did not warrant any serious thought for inhibition of spontaneous combustion. With the planned advent of longwall mining, particularly sub-level caving, with heavy capital investment as well as high production potential, the sealing of a longwall face due to spontaneous heating could not be considered an appropriate solution.Principle of Inhibition of SpontaneousCombustionFrench engineers have established that a fire will not break out when oxygen is 15% or lower in the general body of the air. However, once a fire starts, the percentage of oxygen has to be reduced to 2% - 4% to extinguish it. It is this principle which has been used at Blanzy Coalfield in France to inhibit heating and it is claimed that this has retrieved the integral sub level method of mining. Nitrogen infusion has been used in Frence since 1978 to keep the oxygen content below 14% in the goaf."

Jan 1, 1987

By E. J. Wasp, T. L. Thompson, T. C. Aude

The paper will deal with some of the more important technical aspects of slurry pipelines as they apply to the mineral field. In addition, the use of these technical concepts in arriving at realistic economic figures will be discussed.

Jan 1, 1970

By C. I. Walker

Field tests at a number of large mineral processing operations have been undertaken to better understand the wear life impact of different aspects of pump design, materials of construction and maintenance procedures. Data are presented for wear rates, and typical result variability is explored. To improve the availability of pumping equipment in a milling circuit it is not only important to improve the wear life, but also reduce the variability in the wear life of components so that the incidence of premature failure is lessened. Localised gouging wear due to flow separation and turbulent eddy formation is often the point at which part-holing occurs. A number of improvements to the design of pump impeller and throatbush (suction side liners) to reduce the localised gouging wear are outlined. Also, results are presented on the use of composite materials (mix of metal, rubber and ceramic) for throatbush materials to protect specific areas against wear.

Jan 1, 2012

By I. Mc Dougall, H. Joubert, G. de Villiers

The use of sidewall copper cooling systems to prolong furnace campaign life is becoming an accepted technology solution in the base metals industry. Tenova Pyromet has designed and installed a number of sidewall copper cooling systems in base metals furnaces, including the platinum industry. Apart from increasing the furnace campaign life through the formation of a stable freeze lining, a well-designed copper cooling system enables the plant operator to focus more on optimizing the process to achieve throughput and recovery targets, and to accommodate more varied and available concentrate feed blends. The paper discusses the design of sidewall copper cooling systems for copper smelting and converting furnaces to achieve the above objectives. More specifically, the design of copper cooling systems for top submerged lance furnaces are discussed. An overall increase in furnace heat losses has been raised as a concern for intensively cooled sidewalls. The paper explores the overall heat loss expectations for copper cooled furnaces versus traditional refractory lined furnaces. In addition, the potential use of alternative cooling media is discussed. INTRODUCTION Base metal smelting and converting furnace technologies have been evolving continuously over the past century to satisfy the need for higher throughput, improved efficiency, and longer campaign life. To accommodate these demands, in particular higher smelting intensity and throughput, furnace bath containment systems had to improve. The use of pure refractory lining systems has slowly made room for the use of more intensively cooled lining systems (Joubert, Nikolic, Bakker & Mc Dougall, 2016). These cooling systems evolved from external shell cooling, such as shower or film cooling, to copper plate coolers extending into the furnace refractory lining, and high intensity stave or panel coolers (Verscheure, Kyllo, Filzwieser, Blanpain & Wollants, 2006). Consequently, an increasing number of base metal smelting and converting furnaces are equipped with copper cooling systems, including flash furnaces (Bryk, Ryselin, Honkasalo, & Malmstrom, 1958; Yasuda, Motomura & Kawasaki, 2014; Marx, Shapiro & Henning, 2010), top submerged lance primary smelting and fuming furnaces (Bhappu, Larson & Tunis, 1994; Kim, Lee & Lee, 2000; MacRae & Steinborn, 2018), top submerged lance converting furnaces (Viviers & Hines, 2005; Nikolic, Hogg & Voigt, 2018), primary platinum smelting electric furnaces (Nelson, Stober, Ndlovu, De Villiers & Wanblad, 2005; Jones, 2005; Hundermark, De Villiers & Ndlovu, 2006; Mc Dougall, 2013), and electric slag cleaning furnaces (Joubert, Nourse, Masters & Hundermark, 2005).

Jan 1, 2019

By J. Bakos

Solar Hydrogen Energy Corporation (SHEC Labs) recently constructed a pilot-plant to demonstrate a Dry Fuel Hydrogen Generation System that is powered primarily by sunlight focusing-mirrors. The pilot-plant consists of: A Solar Mirror Array and Advanced Solar Concentrator and Shutter System; and two thermo-catalytic reactors to convert Methane, Carbon Dioxide, and Water into Hydrogen. Results from the pilot study show that Solar Hydrogen generation is feasible and cost-competitive with traditional Hydrogen production. More than 95% of Hydrogen commercially produced today is by the Steam Methane Reformation (SMR) of natural gas, a process that liberates Carbon Dioxide to the atmosphere. The SMR process provides a net energy loss of 30 to 35% when converting from Methane to Hydrogen. Solar Hydrogen production provides a 14% net energy gain when converting Methane into Hydrogen since the energy used to drive the process is from the sun. The environmental benefits of generating Hydrogen using renewable energy include significant greenhouse gas and criteria air contaminant reductions.

Jan 1, 2005

By J. L. Nebreda, Z. Fan, J. B. Patel

"A380 alloy has been widely employed to produce thin-wall components via high pressure die casting (HPDC). During HPDC processing, there is a significant problem of property variation even with the very stable and precision automated casting procedure. The enlarged variation lowers the component performance and affects the steady and uniform property distribution along the whole component. In this study, high shear melt conditioning technology was developed and applied to the melt prior to pouring into the shot sleeve. Experimental results show that with application of intensive melt shearing, the variation of elongation was decreased from 21.8to 13.9%, and yield strength variation was reduced from5.5to 3.6%. The improved property variation is attributed to enhanced nucleation both in shot sleeve and the die-cavity, and to the improved distribution of porosity and secondary phases as a benefit of high shear induced grain refinement. With application of high shear, large number of the Spinel phase (MgAl2O4) particles with double size distribution in average diameter of 80and 300nm were formed. Due to the good orientation relationship and small misfit between alpha Al and MgAl2O4, the particles act as the effective nuclei in shot sleeve and die cavity, respectively.INTRODUCTIONA380 alloy had been widely used for produce automotive components by cold chamber high pressure die casting(HPDC) processing, due to its relative good mechanical properties and cast ability performance, and more important most of A380 ingots were produced by recycled Al alloys. Therefore, to promote utility of A380 will contribute to reducing emission of CO2and to the lightweight of automotive industry as well. When cold chamber HPDC was employed to produce the components, the mechanical properties of A380 alloy always have a distribution range (named variation herein), or in other words the properties were not stable. The reason was ascribed to the typical solidification characteristics occurred in HPDC processing. During HPDC processing, there are three steps of melt movement. The first step is that the melt was poured into shot sleeve at temperature of about 680°C, in which shot sleeve was preheated by few shots of melt filling, or by heater. During step one, the first solidification of melt was happened in shot sleeve and about 20% solid made of coarse a-Al grains was formed(Li, Xiong, & Guo, 2016).Such kind of grains will retain in the final products and deteriorate the properties variation. The second step is that the melt was forced moving forward slowly by plunger at about 0.2–0.3m/s until the liquid melt front to the inner gate of mold. The third step is that the melt moved very fast to complete the filling of die cavity and refilling the solidification shrinkage by fast movement of plunger about 2–3m/s. The second solidification was occurred in die cavity and fine a-Al grains will be formed by high cooling rate at about 500–1000°C/s. From the solidification point of view, the grain size was dominated by nucleation and growth. When HPDC was employed to produce components, the melt quality becomes the priority factor to control the solidification process as the other casting parameters were kept at the same."

Jan 1, 2018

By Long Han, Beijing General Research Institute of Mining and Metallurgy, Yu Xie, Yunhai Zhang, Yangge Zhu, University of Science and Technology Beijing, Yanbo Shang, Xingrong Zhang

"The first-principles method was employed to study the adsorption of hydroxyl calcium (CaOH+) and hydroxyl (OH-) on hematite and quartz surfaces. The calculation results suggested that OH- preferred to interact with the active Fe sites on the hematite surface, whereas OH- adsorbed on the quartz surface by weak hydrogen bond. Though CaOH+ could easily adsorb on the hematite and quartz surfaces by the formation of Ca-O bond, the covalence formed on the quartz surface was apparently stronger than that on the hematite surface, meaning a stronger and more stable adsorption. CaOH+ adsorbed on quartz surface was mainly through the interaction of O-2p and Ca-3d states, and this interaction on hematite surface was weaker.INTRODUCTIONIron Increase and Silicon Reduction Technology (Yu & Duan, 2002) of hematite is mainly through the reverse flotation (silica is floated away from the iron concentrate). There are two ways to achieve this (Houot, 1983). One is to collect quartz by cationic collector directly; the other is to activate quartz by lime and then collect it by anionic collector. There are two main different views with respect to the mechanism of quartz activation: mono-hydroxyl compound theory (Fuerstenau, Rice & Somasundaran, 1965; Fuerstenau & Palmer, 1976) and surface hydroxyl precipitation theory (Hu & Wang, 1988; Wang & Hu, 1990). The former indicated the formation of the mono-hydroxyl complex is one of the two criteria of quartz flotation. The later theory, on the other hand, suggested that surface precipitation is the adsorption of active species of metallic ion on quartz surface. However, most of those researches are based on the solution chemistry of flotation and little is done at the microscopic level.In this paper, by the help of first-principles calculations, the adsorption models, bonding conditions, Mulliken charge populations and adsorption energies of hydroxyl and calcium hydroxyl ions (OH- and CaOH+) on hematite (001) and quartz (100) surfaces were investigated to find out the lime activation of quartz at atomic level, which is significant for the researches of quartz activation theoretically and practically."

Jan 1, 2016

By Joseph W. Mills

"The Mic Mac property comprises 994 acres held under mining concession and approximately 2,000 acres held under development licenses in Bousquet township, Abitibi county, western Quebec.Gold was first discovered in this locality by Tom Duval in June, 1936. In February, 1937, Cassels Duval Mines, Limited, was incorporated under Quebec charter to take over the property. In September, 1937, the property was examined by Agaura Explorations, Limited, and an option agreement was signed on October 6th, 1937. In June, 1938, an option for complete ownership was taken on adjoining claims belonging to Norgold Mines, Limited, and in September, 1938, a mining plant was installed and the sinking of a 3-compartment shaft begun. In June, 1939, an option was taken by Mic Mac Explorations, Limited, on seven claims of Mooshla Gold Mines Company, Limited, that adjoined the Norgold block to the east. In December, 1939, a new company, Mic Mac Mines, Limited, was formed, amalgamating the Cassels Duval, Norgold, and Mooshla claims, as well as two claim groups to the west of the mine known as the Vaughan and West Cassels groups."

Jan 1, 1954

By Thomas E. Shumka

ASTM E2905 describes a two-part standard for electromagnetic methods for preparation and examination of ring gear teeth in the mining sector for SAG and Ball Mill ring gear drives, including pinions? particularly on the addendum, dedendum, and root areas. This practice addresses the need to detect surface breaking flaws electronically and to have the ability to accurately size any surface breaking cracks found on cast and forged SAG and ball mill ring gear and pinion teeth faster and more effectively than other methods. Eddy-current surface arrays are seeing increasing use throughout the industry for the detection of surface breaking flaws in conducting materials. Example applications include examinations of pipelines, bridges, engines, aerospace structures, and any conducting material for surface breaking flaws including cracks. In addition, model-based methods are being used to size cracks accurately found in the addendum, dedendum, and the root of SAG and ball mill girth gear teeth. As visual interpretation of a surface breaking discontinuity on gear teeth is the normal analysis, the colors and 3D images that are provided with this technique, help with visualization and therefore are absolutely invaluable in such circumstances. This practice will help to standardize the use of this nondestructive testing approach.

May 1, 2013

By R. Brough

"Over 25 years ago, SKEGA pioneered the use of rubber linings in grinding mills and rubber is today widely accepted and almost standard material chosen for Regrind - and Secondary Hills. There are, however, only a few Primary Hills in operation with ""solid"" rubber linings because available materials and designs are often not cost efficient in comparison with steel alloys on a Cost per ton basis and/or downtime for liner replacement would be to a high.In other words, solid rubber has limits as any other material. However, 'SKEGA started to think, why not try to use the best properties of rubber as well as steel and combine the two materials together.Nearly 10 years ago SKECA started to test this concept in Rod Mills. A steel cap was vulcanized on to the leading face of the lifter bars, to be installed close to the feed end head (fig. 1)."

Jan 1, 1988

By Lawrence Devon Smith

The selection of the production rate is one of the most crucial decisions to be made in the development of a mineral property. However, it is not uncommon for the production rate to be decided arbitrarily, before any technical evaluations begin, and it is often not reconsidered when better data becomes available. A number of methods are used in the mineral industry to select the production rate for a project. There is general agreement that the size of the ore reserve has a strong influence on this decision, but what other factors are involved? Is there a way to identify an optimum rate? This paper examines the factors that influence the selection of a production rate from the perspective of project economics. The NPV maximum value should be viewed as a “failure” point. The “two times capital” maximum is proposed as a lower limit. A practical check is suggested to confirm that a selected rate is in an optimum range. Production rate assumptions are much more likely to be reviewed for marginal projects, but they should also be reviewed for viable projects.

Jan 1, 1997

By Reinis Sipols

AGENDA ? Introduction ? Definitions and Key features ? PEA - Preliminary Economic Assessments ? PFS ? Preliminary Fesibility Studies ? FS ? Feasibility Studies ? Costs and Risks ? Cash Flow, Economic Analysis and Reporting ? Recommendations for Improved FS accuracy INTRODUCTION ? The reporting of material information on mineral deposits has been governed by NI 43-101 legislation for almost a decade. ? The investment sector depends on the independent, professional QP to provide objective observations, comments and recommendations through all levels of geological, engineering and financial evaluation until a mine construction decision has been made.

May 1, 2013

By K. Esmaieli

ABSTRACT We conducted a series of numerical experiments to investigate the influence of rock mass foliation on impact-induced damage on ore pass walls. The 2D Particle Flow Code was used to simulate three distinct rock masses surrounding an ore pass, characterized by foliation angles of 60°, 90°, and 120° (clockwise from horizontal). Subsequently, we projected a rock fragment against the ore pass walls at a constant impact angle and velocity. The resulting damage increase

Jan 1, 2014

By Bill Charbonneau

Lumen, lm The measurement unit of light emitted by a light source 60W incandescent840 lumens 32W T8 linear fluorescent3200 lumens 54W T5HO linear fluorescent5000 lumens 400W metal halide24,000 lumens

Oct 1, 2010

By X. Xe, B. Myhre, N. Zhou, B. Sandberg, Z. Chen

Effects of microsilica and reactive alumina type on flowability, flow decay and working time of Al2O3-SiC-C castables for blast furnace trough were investigated. The results show that at a targeted self flow values of (80 ± 10)%, water demand markedly decreases with increased microsilica addition. The nature of reactive alumina has a strong influence on flowability of the castables. Higher microsilica content contributes to a longer working time. The flow decays gradually until the working time and then drops abruptly. In addition, microsilica have positive effect on both cold strength and hot strength.

Jan 1, 2004