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By A. Rousselet, H. Gilbert-Tremblay, A. Berton

"Robex Resources interrupted production at the Nampala Mine in September 2014 following throughput and gold recovery results which were below expectations during the first months of operation. After a thorough plant audit, an important brainstorming took place in order to identify an economical path to resume production. It was clearly identified that a significant investment was necessary at the concentrator prior to restarting the plant, namely the addition of a ball mill and a new elution system.The mineral processing simulation software USIM PAC was used in order to simulate the grinding circuit in design. The simulations’ outputs allowed the ball mill characteristics and the surrounding classification devices to be designed with more accuracy. Many ball mills available from second hand retailers were therefore studied in the simulated circuit. The chosen ball mill, which was in perfect condition, had the advantage of being available for rapid delivery on site.The paper first describes the ball mill sizing method in comparison with the conventional Allis Chalmers method. It then describes the phase 2 concentrator start-up (that took place in 2016) with the commissioning of the ball mill, the classification circuit, the gravity concentration, the four (4) new carbon-in-leach (CIL) tanks, and the Zadra elution system (The phase 1 start-up took place in 2014). It finally provides production data compared to expected simulation data, as commercial production was reached in January 2017.IntroductionDesigning a new concentrator or new equipment within an existing concentrator requires significant efforts to identify possible bottlenecks and their causes (i.e. limiting equipment or sectors) and accurate sizing of major equipment can have a tremendous impact on the economy of the whole project. In the presented case study, the ball mill was the critical equipment and oversizing it could have brought the Capex to a level where the project would not have gone through. Inversely, undersizing the mill could have resulted in lower production and therefore no economic viability for the project once it is in operation.During engineering studies, equipment sizing often relies on a static mass balance and one-by-one sizing of all pieces of equipment. The sizing is then left to the equipment manufacturer or in the case of mills, evaluated with empirical models mostly relying on the Bond equations (Allis Chalmers method) [Rowland and Kjos, 1978]. This methodology shows the disadvantage of not considering interaction between equipment in a mineral processing circuit, especially when recirculation occurs. Also, it has the disadvantage of not using the more advanced grinding models that include the use of the whole particle size distribution as well as phenomenological components by only using limited parameters in the ore particle size distribution (i.e. the P80). This can be explained by the lack of data that sometimes needs to be gathered in order to tune the more advanced models but also by the conservative mindset in mineral concentration engineering which does not always favor the use of process simulation. In many aspects of process engineering, Soutex has demonstrated its affinity to using simulation in order to size equipment with more accuracy, consider process variability, simulate complex systems, and study supply chain management (Berton et al., 2015)."

Jan 1, 2018

By H. L. Martin

A joint federal-provincial approach in gathering basic information from industry on mine production, concentrator operations and ore reserves, initiated during 1978, is a major step toward the goal of achieving better government-industry communication through a common data base. Information from questionnaires sent out by provincial governments is shared with the federal government; correct interpretation is ensured by mine visits conducted jointly by provincial and federal representatives. Initial focus is on nonferrous metal mines. The federal Department of Energy, Mines and Resources (EMR) is responsible for a national analysis that is aimed at the early detection of worrisome developments-and their reasons-in the flow from resources to reserves and from reserves to supply of these metals. The heart of the national analysis is the annual construction of a "monitoring curve", showing each metal's aggregated mine production as it would decrease over time if no new reserves and production capacity were to be added from the year of analysis. For a given metal, a comparison of monitoring curves from year to year can reveal early signs of supply stagnation. In anyone year, a monitoring curve in conjunction with foreseen needs for Canadian mine output will show the production gap that would have to be filled from reserves and production capacity yet to be developed. The production gaps for copper, nickel, zinc and lead, the four leading base metals mined in Canada, are shown for the 20-year period ahead, in the context of production achieved during the past 20 years. It is shown that reserve levels commensurate with likely future production levels would require that average annual reserve additions during 1978-98 exceed the average annual additions during the preceding 20 years. Reserve levels of all four metals have declined in recent years. A review of significant discoveries in the last five years suggests that this fall in reserves is not the result of a lack of exploration successes, but of stagnation in development for various economic reasons.

Jan 1, 1979

By Cedric E. Gregory

"A study of model rectangular mine shafts has been made in the wind tunnel, with the aim of reducing air-flow resistance elements to a practicable minimum. An analysis of Table 7 shows an indicated average decrease in resistance of 28 per cent by adopting the over-all modifications involved in the configurations actually tested. Much greater reductions (up to 68 per cent) are indicated by extrapolating beyond the test results directly achieved. Intermediate partial reductions in aerodynamic resistance are shown for individual modifications, such as: (1) about 3 per cent for locating the lagging in the No. 4 (inside flush) position as against the No. 1 position - 8 per cent as against the No. 2 position - and 23 per cent as compared with position No. 3; (2) about 12 per cent for using lagging instead of steel meshwork along the divider separating the skipway from the service compartment; (3) about 14 per cent for using steel gridwork ladder stagings at 3-set intervals instead of similarly spaced wooden stagings; (4) about 12 per cent for using steel gridwork ladder stagings at 3-set instead of at 1-set intervals; (5) about 13 per cent for fitting a streamlined fairing (see Fig. 5) to the upstream face of the skipway divider. Contrary to expectations, an advantage of only 3 per cent is indicated for lagging in the inside flush (No. 4) position over the outside position (No. 1). This slight gain does not appear to warrant the cost of moving the lagging. However, if the lagging is already in the No. 2 or No. 3 position, there is an 8 and 23 per cent advantage respectively."

Jan 1, 1973

By J D. McDonald

This paper outlines the function of the Safety and Compensation Division of the Mining Association of British Columbia. After a general discussion of safety and the safety program now being followed in B.C., the author goes on to describe the wide-ranging aspects of compensation payments and company assessment rates. Special attention is also given to the problem of silicosis in mining operations. In appendices to the paper, the experience rating plan of the mining industry is compared to that recently adopted for the construction industry. Introduction The Mining Association of British Columbia consists of fifty-five member companies, including virtually all the producing mines as well as the larger exploration, contracting and development companies. On completion of an extensive study of safety and compensation in the mining industry, the Mining Association of British Columbia instituted a Safety and Compensation Division in 1954. The director of the Safety and Compensation Division reports to the Executive Committee of the Association. There are two main functions of this Division. First is the prevenion of accidents by encouraging

Jan 1, 1965

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. R. Hughes

Introduction Situated 182 miles east of Vancouver, on the Kettle Valley branch of the Canadian Pacific railway, the Princeton coal field is readily accessible to the Coast markets. The area covers approximately forty square miles and present indications are that the deposits should contain at least 300,000,000 tons of coal. Comparatively little development has yet taken place in this coal field. Since the commencement of recorded output, the collieries operating in this area have produced 1,640,518 tons of coal. The coal field proper includes only the Tertiary deposits adjacent to the town of Princeton and does not include the Coalmont or Nicola deposits. Production has never been on a large scale. The largest annual output from any property was 81, 780 long tons mined at the Granby colliery in 1940. Coal output was first recorded in 1909 and since that time fifteen properties are reported to have either mined coal or to have done prospecting or development work; of these, only two are presently active. However, none of the properties now inactive were closed because their coal resources were exhausted. The accompanying key map shows the extent of the Princeton coal field, and the location of the coal mines and prospects in this field General Geology The Princeton field is underlain by rocks of Oligocene age and is one of the series of more or less isolated Tertiary lake basins in which coal, or lignite, has been found in the interior of British Columbia. Resting on the Nicola group rocks of Triassic age, the Princeton sedimentaries consist of sandstones, conglomerates, shales, bentonite, bentonitic clays, and several seams of coal. Tertiary volcanics occur both above and below the stratified rocks and in places they have been thrust through the overlying measures. In some areas, the coal has been burned to a red ash as the result of vulcanism, while in other parts some of the moisture has been driven from the coal, thus improving the grade. The field can best be described by dividing it into two areas: the Southern area, lying to the south of the town of Princeton, where most of the mining has been done; and the Northern area, to the north of Princeton, where very little development has taken place.

Jan 1, 1947

By R. J. Smyth

A Steel Compression Reinforcement Repair Technique (PetroSleevel) system has been developed that has the ability to repair pipeline defects such as stress corrosion cracking (SCC) without requiring welding to the operating pipeline. The Technology has been used to repair active cracking in ERW seam and cracking in the pipe body. All repairs were performed while the pipeline was in operation. This paper will discuss the engineering theory, testing performed to verify the engineering theory, and examples of actual sleeve installations.

Jan 1, 2005

By R. R. Song, Q. Li, H. Xing, X. C. Wei

Geomechanical modelling of fault stability is an important part of CO2 capture and storage (CCS) research program to ensure its viability and long-term safety. Storage of CO2 in deep subsurface reservoirs requires estimates of sustainable fluid pressures that will not induce fracturing or fault reactivation which could cause fault slip. More importantly, fault slip gives rise to seismic waves, which inflict severe damage to the cap rock of the reservoirs and may result in leakage pathways for the buoyant plume and thus compromise the integrity of seal formations. In this study, we generated a numerical model tuned towards conditions usually encountered in the Shenhua CCS demonstration project in Ordos basin. In particular, with the purpose of evaluating the sensitivity of the parameters as well as their relationships with the moment magnitude of the seismicity, a variance-based sensitivity analysis was adopted for importance ranking of the uncertain input parameters of the given model. However, such flow models could involve one or several spatial inputs, for instance, fault dip, distance between fault and the injection well, friction angle of fault, permeability of fault, Young's Modulus of fault, injecting pore pressure and the stress field. Studying the sensitivity to each of these spatial inputs motivated the present work. The results led to the following conclusions: fault depth and fault dip significantly affect the behavior of the fault and the fault slip becomes violent with the fault depth increasing and fault dip decreasing. Furthermore, the results indicate that slip time increases with the fault dip decreasing and decreases with permeability of fault increasing. In addition, the calculation of seismic moment and moment magnitude of an earthquake demonstrates that it rises significantly with the decrease of fault dip and the increase of fault depth, and it decreases with the rising stress field. The results show that variations of the only controllable parameter injection pressure do not show great influence to the fault behavior compared with other geological factors, which imply site selection is extremely important for the CCS projects.

Jan 1, 2015

By B. Pewkliang, K. Ehrig, E. Macmillan, M. Smith, V. Liebezeit, Y. Li

The Olympic Dam iron-oxide copper-gold (IOCG) uranium-silver deposit is the largest publicly declared uranium, fifth largest copper and third largest gold resource. Currently, the operation consists of an underground mine and integrated processing plant. Uranium is produced from leaching of flotation tailings and is a co-product to copper cathode with by-product gold and silver bullion. The Olympic Dam geometallurgy team began studying ore from the Southern Mine Area (SMA) in 2006 and soon discovered uranium behaviour was far more variable than the behaviour in the Northern Mine Area, which had been mined from the start of the operation in 1988. The primary objective of Olympic Dam geometallurgy is to develop metallurgical performance predictors that reliably describe the process performance of different ore types and distribute these into the resource block model for use as a fundamental input into mine planning. The nature of the uranium mineralisation (compositionally and texturally complex and highly variable) meant that classic mineralogy techniques alone could not provide the resolution required for prediction of uranium extraction. However, the combination of quantitative mineralogy, results from laboratory-scale leach tests and modelling within the geometallurgy program has enabled prediction of both uranium flotation recovery (via association with sulphides) and uranium leach extraction, including at variable leach conditions. These stope-based predictions have supported trade-off decisions between operating costs and uranium revenue, and have predicted the changing recovery as the mining operations have moved into the Southern Mine Area in recent years.

Jan 1, 2020

By P. Morissette

Passive monitoring of support performance during rockbursts was conducted at three deep underground mines. A comprehensive database was constructed of 172 seismic events and the associated damage to support systems at 266 mine locations from January 2000 to September 2012. The majority of pertinent information was obtained through seismic system records and on-site field assessments. This work assesses the quality of collected information and evaluates the dynamic-load demand on support systems in seismically active mines.

Aug 1, 2013

By Brian Putland

Single stage semi-autogenous / autogenous (S/AG) milling has become a common design for a variety of ore types with the advantages of being comparatively low capital cost and flexible for future expansion. The single stage SAG/AG milling option is ideal for starter projects with significant exploration and expansion potential. Currently a number of the largest SAG mills designed are installed in single stage configuration. This paper discusses the challenges associated with the process design of single stage SAG/AG milling circuits, the design flexibility required to ensure a robust circuit and the operating techniques adopted at successful installations.

Jan 1, 2012

By K. Delbeke

Within the framework of the EU Existing Substance (93/793/EEC) and REACH regulations EC/1907/2006), the copper industry initiated in 2000 a comprehensive Voluntary Risk Assessment of copper and several copper compounds. The Italian Government's Istituto Superiore di Sanità, reviewed the process and reports on behalf of the European Commission. Copper exposure levels to man and the environment from production of copper anodes and cathodes, copper powders and copper chemicals as well as fabrication and use of semi-fabrication products and down stream user products were collected across Europe. Environmental and human health effects data were obtained from literature as well as novel research programs and used to deduct safe threshold

Jan 1, 2007

"The outlook for Eastern Canada is decreasing coal production over the next few years; however, a reappraisal of the long-term requirements and increased prices of coal could lead to a revitalizing of the industry. The market for Western coal is expanding and is expected to exceed 50 million tons per year in the metallurgical and thermal power fields. Western coal reserves are currently estimated at 119 billion tons. Technical developments in Eastern Canada include a shearer and gate-end support system to mechanically cut the stall and brushing at the tail-end of a longwall. In Western Canada, the most modern equipment is used in mining, beneficiating and shipping coal. Results to date on the underground hydraulic experiments exceed expectations. The importance of reclamation is recognized and plans have been made to restore and re-vegetate disturbed areas and mine dumps. In Eastern Canada, experiments were started to determine the feasibility of coal reclamation from mine dumps, including one dump that is on fire. The Mining Research Centre, Mines Branch, continued to conduct research work oriented toward solving Canadian mining problems The Western office of the Centre, opened in 1970, was set up primarily to study problems associated with a resurgent coal industry."

Jan 1, 1971

By N. Melnyk

"FOREWORDThis paper provides a unique description of a method devised for mining a very thick steeply dipping seam of soft gassy coal which was prone to spontaneous combustion. The editors con¬sider that the information in this paper should be important to those who may have to consider mining such seams again at some time in the future and therefore believe that the paper warrants reprinting in the present volume. The author was ask¬ed to review the paper and to add any additional relevant in¬formation. He provided the accompanying footnote, only a month before his death on April 22, 1982.IntroductionIn the past, the Cadomin Coal Company has opened four mines, all in the same coal seam or its folds. Three of these were opened from river level by horizontal entries or rock tunnels. and the fourth, the present working mine, by vertical shafts. This paper deals largely with some operating phases of this fourth mine, with which the writer has been associated.The seam worked here is a thick, steep, bituminous seam, and the writer feels there is a paucity of published data on the mining of such seams. Possible reasons for this are that such seams do not lend themselves to intensive development or mining, there is little chance to mechanize because of the extreme pitch, and operations are fraught with many problems. In addition the present operations in this particular' seam are being carried on at a level below the former workings, introducing new problems, not encountered on the upper level.Coal will, without question, long continue to be an impor¬tant factor in the national economy, and some of the best coal is to be found in thick, steep seams. But with the exhaustion of the easily-mined coal near the outcrops, future coal will have to come more and more from lower levels. At Cadomin there is still considerable coal on the second level, below the old river-workings, and there is a possibility that, in the future, still lower levels will be worked. It is the purpose of this paper to indicate some phases of such lower-level operations and to invite discussion."

Jan 1, 1985

The NorthMet deposit of PolyMet Mining is located in northern Minnesota, adjacent to the Iron Range. The deposit is polymetallic with values of Cu, Ni, Co, Zn, Pt, Pd and Au. The processing route selected for extraction of these values utilizes bulk sulfide flotation followed by hydrometallurgical treatment. The hydrometallurgical process has been thoroughly tested on the bench and pilot plant scale at SGS Lakefield Research. The major steps in the process are; ? Chloride-assisted total pressure oxidation for extraction of base and precious metals ?Thickening/filtration/washing of the barren residue from total oxidation ? Reduction and precipitation of Au, Pt, Pd from the oxidation solution ? Partial neutralization of autoclave acid using limestone ? Copper SXlEW for production of copper cathode ? Treatment of a portion of the raffinate from Cu SX to recover NilCo/Zn as either a mixed Ni-Co-Zn hydroxide or as separate Ni hydroxide, Co hydroxide and a Zn sulfate solution. ? Recycling of the remaining raffinate to the autoclave as coolant The process flowsheet, chemistry and bench/pilot plant test results will be reported in this paper.

Jan 1, 2007

By Tedd E. Lister, Andre Anderko, Peiming Wang

Mobile electronic devices such as smart phones and tablets are a significant source of valuable metals that should be recycled. Value metals in phones are gold, palladium, silver, copper, cobalt and nickel. Devices now contain increasing amounts of rare earth elements (REE). Effective recycling schemes should include the recovery of these critical materials. Targeted recycling of items containing more of the less available critical materials could address their future criticality. This presentation will describe an electro-hydrometallurgy approach to efficient recycling of metals from scrap mobile electronics. The electrorecycling (ER) process generates oxidizing agents at an anode while reducing dissolved metals at the cathode. Development of the process involved generation of E vs pH diagrams, complemented with metals dissolution experiments used to assess the effectiveness of various solution chemistries. Although several schemes were envisioned, a two stage process has been the focus of work: 1) initial dissolution of Cu, Sn, Ag and magnet materials using Fe+3 generated in acidic sulfate and 2) final dissolution of Pd and Au using Cl2 generated in an HCl solution. Results from laboratory work will be discussed.

Jan 1, 2014

By N. Hiroyoshi

In the leaching of chalcopyrite with sulfuric acid solutions, the copper extraction rate reaches a maximum at a given redox potential. This article reviews our studies on the determination of the optimum redox potential for chalcopyrite leaching. Shaking flask and column leaching experiments for a chalcopyrite concentrate were performed under various conditions, and the results were analyzed using a normalized redox potential defined from a reaction model assuming the formation of an intermediate CU2S from chalcopyrite. Factors, such as metal ion concentrations, solid/liquid ratio, and presence of iron-oxidizing bacteria, caused significant variations in the copper extraction versus time plots. However the copper extraction rate versus normalized redox potential plots were independent of the above factors and the copper extraction rate reached a maximum at the normalized redox potentials around 0.43. Converting the normalized redox potential to the solution redox potential gives the optimum redox potential for chalcopyrite leaching as a function of cupric and ferrous ion concentrations. This semi-empirical equation can be used to predict the optimum redox potential during leaching operation, and is useful to design the redox-controlled heap leaching for chalcopyrite.

Jan 1, 2007

By Andreas Oberrauner

Content ? What is? an introduction ? Crushing technology ? Conveying in pits ? Pit-exiting strategies ? Mine Planning in IPCC ? Summary/Conclusions EHS slide ? Sandvik?s objective is zero harm to our people, the environment we work in, our customers and our suppliers ? Current EHS-figures will be added in August! Who is this? Andreas Oberrauner ? Born in Austria ? Living in Cologne (Ger) ? Mining Engineer ? Montanuniversitaet Leoben (Austria) 2000-2005 ? PhD on Mineral Processing 2008-2012 ? Sandvik Mine Planning Department ? Main task: Provide practical and efficient solutions for mining-challenges

Aug 1, 2013

By DALE MacGREGOR, VERA TUREK

lndusmin Limited acquired the St. Donat quartzite deposit in 1967 to produce high-quality silica for use in the sandblasting and silicon carbide industries. The quartzite, of Grenville age, is highly friable and porous. This is due to numerous small, kaolinite-coated cavities in the quartzite; the cavities were formed through leaching, probably by rising hot solutions.

Jan 1, 1984

By M. Maldonado, J. A. Finch

"A flotation bank consists of a serial arrangement of cells. How to optimally operate a bank remains a challenge. This article reviews three strategies for optimizing bank performance: air profiling, mass-pull (froth velocity) profiling and Peak Air Recovery (PAR) profiling. These are all ways of manipulating the recovery profile down a bank, which may be the property being exploited. Mathematical analysis has shown that a flat cell-by-cell recovery profile maximizes the separation of two floatable minerals for a given target bank recovery when the relative floatability is constant down the bank. Available bank survey data is analyzed in respect to recovery profiling. Possible variations on recovery profile to minimize entrainment are discussed.INTRODUCTION Flotation is used to separate valuable minerals from each other and from gangue. To reach a target metallurgical performance, usually assessed in terms of concentrate grade and recovery, feed is passed through stages such as roughing, cleaning and scavenging. All these stages comprise serial arrangements of flotation cells known as banks, lines or rows. Although a bank is the simplest interconnection of cells in a circuit, i.e. the tails of one cell is the feed to the next cell down the bank, how to operate each flotation cell in a way that the whole bank performance is optimized remains a challenge. Significant efforts have been made towards understanding the effect of operating variables on the flotation performance of an isolated cell (Lynch et al., 1981; Finch and Dobby, 1990; Gorain et al., 1998). However in the case of banks the variables that can be manipulated increase with the number of cells in the bank and the problem of how to manipulate them to achieve optimum performance is difficult even disregarding variation in ore characteristics (Lynch et al., 1981, p. 16). In general, the more manipulated variables available the better for optimization purposes, however without clear guidance how to effectively use them it becomes an “embarrassment of riches”."

Jan 1, 2012