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By Tim Gartner

This paper introduces a new application of a proven technology to provide dynamic, voltage regulation in underground mine electrical distribution systems. This technology acts to ?stiffen? the electrical power feeding continuous miners and generally raise and improve the voltage regulation at the continuous mining machines which may be located over long cable distances from the mine incoming electrical substation. This is extremely valuable for large underground continuous mining operations that use high power electrical mining machines fed over very long cable lengths (measured in 10s of km, from mine shaft to mine operating face). This new technology provides fast acting dynamic voltage regulation (voltage support) while starting continuous borers and extensible conveyor belts. Additionally, if the mine suffers from a lower distribution voltage due to long cable lengths, this new technology will raise the overall voltage at the mining machine, which can increased mining machine production and lead to longer motor life. The technology is based on voltage source converters operating as static VAR compensators specially packaged for the harsh underground mine environment. While static VAR compensator technology has been successfully used in utility and large industrial applications for many years (including open pit mining and arc furnaces), it has not (until now) been applied in underground mining. The paper will present the problem of poor voltage regulation in underground mines on weak electrical utility networks. It will then discuss some of the alternatives that have been used to resolve this voltage problem. It will then introduce the new technology used to solve the problem and review the issues involved in using this technology in the harsh underground environment. Finally, the paper will present preliminary performance results from an actual installation in a large underground continuous mining operation in Canada.

May 1, 2003

By S. Kelebek, B. Ingram, C. Gibson, T. MacNeil, M. Aghamirian

"The beneficiation and upgrading of pyrochlore from its ores is carried out through flotation. In industrial practice, upgrading is conducted in a two-stage flotation process in which pyrochlore flotation is carried out after gangue mineral pre-flotation (carbonate, silicate, sulphide or phosphate reverse flotation). In this study, the flotation of pyrochlore from a low grade carbonatite ore was performed at the laboratory scale following a two-stage flotation process in which carbonate minerals were floated in advance of niobium minerals. In parallel, a simplified flotation process was developed in which pyrochlore was floated directly from gangue minerals at increasingly acidic pH. Laboratory results indicated that both two-stage and direct flotation provided similar results in terms of niobium grade-recovery. Based on these results, a large scale, integrated pilot plant was conducted using a direct flotation flowsheet. While the elimination of reverse gangue flotation resulted in flowsheet simplification, the dissolution of carbonate minerals and the subsequent effect of dissolved cations on the floatability of pyrochlore added an element of complexity. A comparison of results from locked-cycle laboratory testing and pilot plant testing highlights the challenges of scaling up a complex flowsheet. A case is made for the direct flotation process and the key parameters to achieving success in large scale direct flotation of pyrochlore are discussed.INTRODUCTIONPyrochlore (Ca,Na)2Nb2O6(OH,F) is a niobium bearing mineral which has been the primary global source of niobium since the first pyrochlore mine commenced operations in the late 1960s (Gibson et al., 2015a). Preceding the discovery and development of high grade pyrochlore deposits in North and South America, the majority of global niobium supply came from gravity concentration operations of columbite (Fe,Mn)Nb2O6, across Africa (Perrault and Manker, 1981)."

Jan 1, 2016

By Daniel E. Walsh, P. D. Rao

"A four-inch compound water cyclone (CWC) was tested to evaluate its gold recovery characteristics when processing -4.8 mm run-or-pit, placer material. Neutron activated placer gold particles (840 to 37 microns) were used as radiotracers (/98Au) in a closed circuit ewe test loop to determine concentrator recovery; a procedure believed unique to this study. The effect on gold recovery of gold size and shape, feed pulp density, feed pressure, vortex finder clearance (VFC), ewe cone type, top-size of the feed solids, presence or absence of heavy minerals in the feed, and the quantity of-37 micron slimes in the feed was investigated in over 300 tests.CWC concentration ratio and the top-size of the underflow solids were both affected by cone type, VFC, and feed pressure. Gold recovery was significantly affected by gold size, gold shape, and concentration ratio. These effects are complex, because significant size-concentration ratio and size-shape interactions exist. Radiotracer techniques showed gold particles had a residence time within the ewe of approximately one second. This study suggests ewe gold recovery is a concentration. This work suggests ewe gold recovery is a function of particle size and shape, and the flow rate through the cyclone. CWC cone ""bed density"" is considered important only as a thin, protective layer, which shields coarser gold particles from the entraining currents and facilitates their movement through the CWC.IntroductionCompound water cyclones (CWC), or automedium cyclones, are enhanced gravity concentrators for the beneficiation for slurries of sand, coal, and ground ore (Fig. 1). They are called compound water cyclones because of the compound slopes of their basal cones (Fig. 2) and are operated to suppress classification phenomena in favour of gravity concentration effects. The compound water cyclone is not a new wet concentrator. It was developed in the late 1950s by Dr. Jan Visman through research sponsored by Canada's Department of Energy, Mines, and Resources. Since that time, it has become a common unit in coal washeries for cleaning fine coal. CWCs and other versions of concentrating cyclones have also shown promise for heavy minerals and precious metals recovery."

Jan 1, 1988

By S. Tavani, T. Rees

The current mining operations at Newmont Boddington Gold Mine (NBG) commenced in 2008, and commissioning of the processing plant started in the latter half of 2009. Metso Process Technology and Innovation were engaged to assist NBG with commissioning and project ramp-up through the implementation of a comprehensive “Mine-to-Mill” Process Integration and Optimisation project. This methodology entailed extensive data collection which included drill and blast audits, ore characterisation, comprehensive comminution circuit surveys and review of operational data to assess the limitations within the current mining and processing operations. The results of these investigations have been used to define the operating base line of both the mining and processing areas and identify improvement opportunities. The use of modelling and simulations, utilising actual production data, has allowed for multiple scenarios to be evaluated, minimising the requirement for actual trials and thereby minimising impact on the operation. Improvements implemented to date include: the introduction of routine rock strength measurement for inclusion in block models, modifications to blast design improving ROM fragmentation and downstream comminution process performance, and changes to improve performance of secondary crushing and grinding circuits. Close cooperation between the mine and plant personnel is playing a significant role in overcoming the challenges presented to this operation and further improvements are targeted for the second full year of process plant operation.

Jan 1, 2012

By Paul Hughes

Purpose of Research ? What are the loading mechanics of paste against barricades? ? What is the capacity of the composite paste fill fences? ? Based on the loading mechanics of the paste, do the fill fences pose a risk of failure? Outline ? Glossary of Terms ? General Introduction ? Research Methodology ? Site Description ? Instrumentation Program ? Results ? Analysis ? Conclusions ? Recommendation for Future Work

May 1, 2008

By Peter R. Drummond

THE paper consists of four sections: (1) a discussion of early work; (2) presentation of the results of a chemical investigation of Falcon-bridge nickel-copper blast-furnace matte; (3) application of the results of this investigation to mattes in general; and ( 4) a summary of conclusions. All general discussion will be confined to the fundamental system of ferrous-cuprous sulphides (FeS-Cu2S). Nickel-, lead-, and zinc-bearing mattes will be treated as minor varieties of the parent system. DISCUSSION OF EARLY INVESTIGATIONS Matte investigations may be divided into three classes: first, those treating the sulphides as alloys-theoretical studies of the system FeS-Cu2S, such as those of Hofman (ll)t or Carpenter and Hayward (2); second, chemical research on mattes made under smelter conditions, such as that carried out by Hawley (3) or Avetision ( 4); third, combinations of the . above, such as the investigations of Gibb and Philp (5) or Fulton and Goodner (6). Much research in the first of these classes, including determinations of . freezing points and of data for structure-composition diagrams of the system FeS-Cu2S, was carried out in the period 1890-1910. LeChatelier and Ziegler (1, 13) proved that FeS, when heated alone above its melting point, dissociated in part, and Friedrich ( quoted by Fulton, 6) showed the same for Cu2S. The reactions may be expressed by the following equations: [xFeS yFe + yS (volatilized)+ (x -y)FeS xCu2S )'Cu+ yS ( vohtilized) + (x -)')Cu,S ] Sulphur is lost by volatilization, leaving a melt of metallic iron plus ferrous sulphide in the one case, and of metallic copper plus cuprous sulphide in the other. If the mixed sulphides are heated far above their melting points, there results either an iron-rich matte containing Fe-FeS-Cu2S or a copper-rich matte containing FeS-Cu2S3-Cu, depending on the relative amounts of each sulphide in the mixture.

Jan 1, 1940

By D. A. Temple, G. O. John

Until recently, the approach to the problem of treating complex ores bas been to produce, insofar as is possible, mono-metal concentrates which are treated in traditional zinc, lead and copper smelting circuits, with the residues and by-products from some of these circuits being retreated for the recovery of contained values either by a separate residue treatment process or along with the primary feed to the appropriate circuit. The continued development of the Imperial Smelting Process, with its ability to treat poly-metal concentrates, calls for a re-examination of the traditional approach to this problem, and this the paper attempts to do. A survey of recent progress in the technical development of the process is made and a summary of current operational performance is included.

Jan 1, 1971

By Werner Unland, Nick Holl

"The paper presents the engineering design and experience gained so far with a dewatering system for an open-pit uranium mine planned at Key Lake in Northern Saskatchewan.The results of hydrogeological investigations preceding engineering exhibit an extensive unconfined overburden aquifer hydraulically connected with the underlying Athabasca Formation and basement rocks, both of relatively low hydraulic conductivity. The overburden aquifer is embedded in a bedrock trough, with the deepest depression between the planned pits. The hydrogeological data were used in a numerical dewatering model simulating groundwater flow atdifferent stages of the pit development.Based on the model results, the engineering design had to provide for different pumping rates, varying between 1.0 and 0.21 ms/sec. This problem was solved by using a double line pressure system. The design concept for the complete peripheral discharge system and the well design used for 26dewatering wells are discussed.Experience with reverse-circulation techniques applied for the construction of the dewatering wells is presented. Theoretical and practical considerations which led to the constructionof wells of different diameters are discussed.The design of the in-pit dewatering system provides for seepage ditches, horizontal drains, pit-bottom sumps and inpit dewatering wells where required."

Jan 1, 1980

By J. T. Sims, C. E. Karayannopoulos

Today's rare earth industry is undergoing significant and rapid evolutionary change toward greater reliability and diversity of supply, increased security of supply chains, and better price forecasting. Technology innovation is reducing rare earth production costs while decreasing the impact of producers on the environment. Advances in rare earth material science are reducing the need for relatively scarce heavy rare earths (HREEs) in high-performance neodymium-iron-boron (NdFeB) permanent rare earth magnets and opening the NdFeB magnetic market space for a broader range of downstream applications. Rare earth producers such as Molycorp are increasingly able to offer long-term supply agreements with forward price predictability, something that has not been the case for many years. All of these trends are helping to restore the confidence of customers and other stakeholders in the rare earth space. That increased confidence is likely to bolster global demand for rare earth materials and expand innovative utilization of these remarkable materials.

Jan 1, 2014

By Peter M. Power

A microscopic study was made of a series of simultaneous slag and metal samples taken from a low carbon basic open hearth heat. An attempt was made to identify the various micro-constituents found. As the various impurities in the bath are oxidized, the metal structure changes from that of high-phosphorus white cast iron to that of low.-carbon steel. A detailed study of phosphorus distribution is included. The acid run-off slag has an .acicular orthosilicate structure which changes on 'shape-up' to a very basic tri-calcium silicate and calciuim ferrite structure. Many unidentified minor constituents are present in the slags. Though metallography will never replace chemic.al analysis of the bath, the microsopic study of polished slags has some promise of being useful in slag control work.

Jan 1, 1956

By Chris M. Healey

"Abstract- The Jasper Gold mine in northern Saskatchewan produced a total mill feed of 140 127 tonnes at an average grade of 19.0 g/t Au. Both diamond drilling and chip samples from under­ ground workings returned extremely high values, up to 12 851 g/t (375 oz/I) Au over 0.10 meter from a chip sample. In the presence of such extremely high grades, the accurate estimation of reserves is a major problem.ln the first part of this study, production data from the mine were used to evaluate the results of a variety of reserve estimation techniques in this environment. In two out of three cases studied, indicator kriging with assays cut to 342.9 g/t (10 oz/I) gave extremely good results. In the third case, however , indicator kriging gave unacceptable results. Instead, lognormal kriging of uncut data gave the best results.Secondly, from the same database, a number of drill-hole spacings were simulated, and reserves estimated from the simulations. As may be expected, the results of this analysis show increasingly better results with tighter drill-hole spacing. However, even with a 5 m by 5 m spacing the variation from actual grade was quite large. This is not a systematic under- or over-estimation of grade, rather a random scatter of results .The results of this study show very clearly the problems of deriving good estimates of reserves when extremely high-grade samples are encountered. There is a high degree of randomness to this database, so reserve estimation in this situation will remain a high-risk operation."

Jan 1, 1993

By G. A. Gross

"Nearly 90 per cent of the iron ore produced in Canada is derived from iron-formation or bedded iron deposits. About 70 per cent of this consists of concentrates obtained from iron-formation; another 20 per cent was formed by natural enrichment processes.Four principal varieties of iron-formation are recognized -the Algoma, Superior, Clinton and Minette types. Differences in their geology, mineralogy, chemical com-position and environment of deposition are of special significance in their evaluation as ore.The properties of the ores, including grade, beneficiation qualities and minor element content in taconites, metataconites and naturally enriched ores, reflect characteristics of the primary stratigraphie units from which they are derived. A detailed description of the stratigraphie facies is essential for efficient utilization of these source beds."

Jan 1, 1966

By Longjiang Li, Song Mao, Zhengyang Qiao, Qin Zhang, Guizhou University, Ling Wang

"After a study on the advantages and disadvantages of flotation column, according to the limitation of ordinary flotation column only is used for a flotation of microgranular minerals, the paper designed a new kind of layered convection coarse particle flotation column.Using a bauxite to test the rationality of the flotation column.The test results show that the new layered convection coarse particle flotation column is feasible.It has certain advantages about coarse particles flotation.INTRODUCTIONFlotation column has many advantages, for example,a simple structure, high efficiency and energy saving, the obvious advantage of fine particles flotation , the index superior and so on. The advantages gradually getting people's recognition. Research of flotation column has been a breakthrough, however, due to it only is used for the flotation of microgranular minerals, and the microgranular mineral particles will lead to a series of problems, and makes the processing cost is increased. Due to increase grinding fineness can save the grinding time and reduce the cost of grinding, also can avoid the disadvantage of fairly granular mineral particles cause a deterioration in the flotation. So it is necessary to research a kind of coarse particle flotation column.After a research on the advantages and disadvantages of flotation column, the authors designed and manufactured a new layered convection coarse particle flotation column, the flotation column both in theory and operation is better than flotation machine.DESIGN OF THE LAYERED CONVECTION COARSE PARTICLE FLOTATION COLUMNAdvantages and Disadvantages of the Traditional Flotation ColumnIn the field of mineral processing, as the increasing proportion of ore that has low grade, fine dissemination size, complex mineral composition characteristics. The limitations of traditional flotation machine is increasing[1],for instance, the high energy consumption, severe wear, inconvenient configuration , large amount of maintenance and so on. Compared with flotation machine, the flotation column with high separation efficiency, low investment and production cost, covers a less area low installation cost, less reagent dosage, more suitable for separation of fine particles and can automatically control, etc[2]. At present, the ore is facing the world energy crisis situation, and becoming increasingly difficult to flotation. So it is important to invent a coarse particle flotation column."

Jan 1, 2016

By H. C. Boydell

Introduction Situated in the district of South Lorrain, some 16 miles southeast of Cobalt, Ontario, and reached from that centre either by branch line of the T. & N. O. railway or by what, for a mining camp, is a reasonably good road, the Keeley mine, owned by the Keeley Silver Mines,' Ltd., has had its history recorded by C. W. Knight (1). Silver was first discovered in South Lorrain, in Woods' vein, on Keeley property, in 1907, and the Keeley mine has been described by Knight (2) and Bell (3). The total production to February 28th, 1930, has been 10,760,107 ounces of silver and 1,285. 434 pounds (weight) of cobalt.

Jan 1, 1931

By P. H. Agson Gani, T. Sitorus, N. P. Widodo

"PT ANTAM UBPE Pongkor underground mine use blasting to develop its tunnels which will cause poisonous and dangerous gases trapped inside mine. To analyze this case, a study of mine ventilation, the dispersion of carbon monoxide (CO) gas concentration and diffusion coefficient is commenced. At the end, the re-entry time formula will be determined. Results indicate that this study is site specific and could only be applied in the place this study executed. The aim of this study is to be further developed by applying Principal Component Analysis (PCA) to find a universal re-entry formula. KEYWORDS Mine Ventilation, Re-Entry, Smoke Clearing, Diffusion Coefficient, Carbon Monoxide Gas, Gas Dispersion INTRODUCTION Pongkor underground mine is using cut and fill as its mining method. Thus, its development and production processes require blasting to develop its tunnel. This process caused poisonous and dangerous gases spread and trapped inside the mine, one of them is carbon monoxide (CO) gas. CO is formed in an unbalanced reaction of explosives detonation and could be the cause of headache, blackout and death to people who inhale CO at certain concentration (McPherson, 2011; Hartman, Mutmansky, Ramani, & Wang, 2012). Mine ventilation system is installed in the mine to resolve this problem. Mine ventilation play an important role to disperse CO gas by absorb the poisonous/dangerous gases and deliver clean air into mine. The important parameter is diffusion coefficient, because diffusion is affecting particulates or gasses spreading from its sources throughout the mine. Diffusion coefficient is the total diffusion in axial direction of turbulent flow mainly by convection of bulk motion, advection and eddy diffusion, while the effect of molecular diffusion is appreciably negligible (Widiatmojo et al, 2015). Taylor (1953, 1954) develops a theory about the dispersion by inducing a slow stream of solvent into a capillary tube. Taylor used Reynolds assumption of radial diffusivity to be analogous with the transfer of the matter in turbulent flow as well as the transfer of momentum and heat. Then, Taylor proposed the formula of diffusion coefficient, D (m2/s), against pipe diameter and turbulent shear velocity are as follow:"

Jan 1, 2019

By Y. Yhang, D. C. Sego

ABSTRACT This paper evaluates the potential of freeze-thaw dewatering using Albian mature fine tailings (MFT). Freezing tests were first performed to study the effect of freezing rate on dewatering efficiency. Lower freezing rate resulted in higher thawed solids content and shear strength. Subsequently, large strain consolidation tests were conducted to investigate consolidation behaviour and how it is affected by freeze-thaw. The consolidation behaviour was presented in terms of effective stress versus void ratio and permeability versus void ratio. The results can be used to predict the field behaviour of Albian MFT and optimize the application of freeze-thaw for MFT dewatering.

Jan 1, 2014

By C. M. Kleemann

The paper describes the present milling practice at Western Mining Corporation Limited's new nickel mine at Kambalda in Western Australia. It details the crushing, autogenous grinding, flotation and spray drying circuits for the production of a nickel concentrate. It also indicates some of the metallurgical problems which have been encountered in concentrating this ore.

Jan 1, 1973

By Jiuhua Xu, Yuling Xie, Fenglei Bie, Neng Jiang

"Abstract - The Xiaoqingling Mt. area is one of the most productive gold districts in China. The gold-bearing quartz veins are controlled by a series of east-west shear zones within the Archean Taihua Group, and related to the late Yanshanian (Cretaceous) granite. The major metallic minerals are native gold, electrum, pyrite, galena, chalcopyrite and sphalerite, with gangue minerals dominated by quartz, sericite, ankerite, and calcite. The host rocks are mainly amphibolite, plagioclase gneiss, and migmatites. Principal alteration is sericitization, silicification, pyritization, and carbonization.There are four generations of hydrothermal quartz in altered rocks of gold deposits. The earliest generation of quartz, (Q1), occurs in altered amphibolite gneiss and migmatite, and typically contains fluid inclusions with halite crystals (type A) and two phases, (L+V), of fluid inclusions (type B). The salinities of type A inclusions are 32 wt% to 52 wt%, with dissolution temperatures of halite crystals being from 155°C to 465°C. The second generation of quartz, (Q2), occurs as a fine-grained aggregate associated with sericite, and has small (less than 3 µm) type B inclusions. The third generation of quartz, (Q3), occurs in mylonitic, intensively altered rocks and specially beresite (a type of rock composed of quartz, sericite, and pyrite) near the veins, and contains large amounts of CO2-rich fluid inclusions (type C-fluid inclusions with liquid CO2 and type D-fluid inclusion with high density CO2). The CO2 contents of type C range from 72.6 to 87.4 mol% in gas phases, and 35.7 to 68.3 mol% in liquid phases, based on Laser Raman analysis. The homogenization temperatures of fluid inclusion type A and C are from 215°C to 380°C, and from 210°C to 325°C, respectively. The minimum trapping pressure of fluid inclusions is estimated as 80 MPa to 170 MPa for type A, and from 57 MPa to 190 MPa for type C, which approximate to those of fluid inclusions in vein quartz.The ?18O of quartz are from 10.4‰ to 11.0‰ for Q3 of altered rocks, and from 10.7‰ to 12.8‰ for stage I quartz. The calculated ?18O of fluid inclusions varies from -1.3‰ to 6.0‰. The ?D of fluid inclusions ranges from -67‰ to -59‰ and from -81‰ to -48 ‰, respectively. It is concluded that the water in the hydrothermal fluids both reacting with wallrocks and precipitating orebodies could have been mainly of magmatic and/or metamorphic nature. However, local meteoric water might have been important in late mineralization, because of a distinct oxygen-shift toward the meteoric water. The ?34S values for pyrite of the ores range from -7.1‰ to +7.1‰, with an average of +2.9‰. Those of other sulfides (chalcopyrite, galena, and sphalerite, range from -12.5‰ to 8.3‰. The ratios of lead isotopes for galena of the ores are: 17.06 to 17.31 (206Pb/204Pb), 15.43 to 15.74 (207Pb/204Pb) and 37.58 to 38.45 (208Pb/204Pb). In summary, ore-forming fluids in the Wenyu-Dongchuang gold deposits may have originated from a mantle and/or lower crust source, and ore materials were derived from the Precambrian basement, the Taihua Group."

Jan 1, 1998

Strengthening a mine with the Power of their Employees: ?Imagine if the global economy collapses, your head office calls, and tells you to shut down for 3 months... now what do you do? ? HVC Business Improvement Initiative Why did we need help ? External Events ? How we responded ? How we worked with Westwind ? Alignment ? Priorities ? Coaching ? Focus Groups ? Innovation ? What worked / Opportunities ? Questions

Nov 1, 2011

By Thomas S. Falk, Nils G. Lindberg

The first industrial COBO (Cold Bound) pelletizing plant began operation in May 1975 at Trollhiittan, Swede n. A technical description of the process, together with operational experience with the plant, forms the basis of this paper.

Jan 1, 1976