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By Svato Prochazka

Content: ? commonly used drive systems ? drive system efficiency ? introduction to SR technology ? SR drive system advantages Commonly Used Feeder Drives Technologies ? VFD + induction motor ? hydraulic drive + hydraulic motor SR drive + SR motor

May 1, 2010

By Hans von Michaelis

"INTRODUCTIONThe renaissance in gold and silver recovery technology has continued to unfold and it is appropriate to review some of the useful new technologies as well as try to identify some of the industry's future needs and frontiers.The remarkable strengthening in the US dollar has resulted in a relatively low gold price in US Dollars of around $310/oz at the time of writing and silver at $6.25/oz. This general softening in the dollar prices and the recent confusion as to environmental compatibility of cyanidation tailings and effluents, has led to a slowdown in announcements of new operations. Another reason for the slackening off in the USA is that in the past few years a large part of the capital has come from oi I and gas companies that now seem to be losing interest in mineral ventures, and foreign investors for whom the dollar is becoming out of reach. In the author's opinion this represents an unprecedented window of opportunity.Elsewhere in the world where local currencies have weakened, the price of gold is at or close to its all time high.For example, in South African Rands, the gold price was R571.00/oz when the rand was US$1.47 and the gold price reached US$800. Now at US $309/oz and with the Rand at US$0.51 = Rl .00, the local gold price is R600. The price of si Iver in Mexican pesos is not much less than it was when silver reached US$50/oz. Gold, and silver prices in local currencies outside North America are still buovant and at levels where additional investment in new projects is more encouraging.Even in Canada where the dollar is worth about US$0. 75, this provides a smaller but significant cushion compared with US operations. Considering the present strength of the US dollar and even the Canadian dollar relative to many other gold producing countries, there should be significant investment opportunities at today's prices. Mining companies have started to descend on Brazil, for example, where in a matter of just a few years annual gold production has increased from 10 to 70 tons. In South Africa, a Canadian company backed by Swiss financing has been able to take over a Witwatersrand gold mining operation and is installing a huge new tailin9s retreatment plant to process about 1 million tons per month of tailings."

Jan 1, 1985

The stability of paste fill bulkheads forms an integral part of a successful paste fill system. Bulkheads are constructed at the draw points of open stopes to contain paste fill while the initial pour cures and forms a consolidated plug. Mobilization of uncured paste fill as a result of a bulkhead failure can lead to significant consequences, including endangering the safety of personnel, property damage and production losses and delays. The loading conditions in the paste fill and the resultant lateral loads on the bulkheads are complex and are dependent on many factors. This paper presents a case study of several paste fill bulkhead failures; the results of an in-situ pressure monitoring program to ascertain the pressure loads, and the subsequent paste fill bulkhead evaluation.

May 1, 2007

By W. T. Sampson

Introduction The Kirkland Lake (Ontario) property of Wright-Hargreaves Mines, Limited, - consists of four claims. The two main shear zones or 'breaks' of the Kirkland Lake camp extend through three of these claims, for a distance of approximately 3,500 feet. These claims are on the northeast side of the original lake. The water in this section of the lake has now been replaced with mill tailings. The degree of success of any completed undertaking, especially in the mining industry, reflects the personnel involved. I state with pleasure that the successful deepening of No. 5 winze from 6,400 feet to 7,272 feet was largely due to the co-operation and skilled workmanship of Shaft Captain J. Myelde and his efficient 'leaders'. This winze was sunk at a time when it was most difficult to obtain experienced shaftmen, with the result that the crews did not wholly consist of experienced men (although their desire to learn shaft sinking soon gave good results). This condition added greatly to the responsibilities and duties of those in charge, whose first consideration was for the safety of those engaged in the work, and I take great pride in recording that the entire sinking programme was completed without a lost-time accident. Location of Winze Due to the information obtained through deep diamond-drill holes collared below the 6,000-foot level being of sufficient importance to warrant further exploration, it was decided to deepen the existing No. 5 winze rather than sink another winze. This decision meant that the sinking must be co-ordinated with and proceed simultaneously with operations in the winze, where mining was being carried on between the 3,900-foot and 5,100-foot horizons, inclusive.

Jan 1, 1948

By C. Pelley, S. Kelebek, T. Katsabanis, B. Nanthakumar

"As part of a larger investigation on generation of fines from mining activities and their effect on downstream operations, ore samples from Onaping area stockpiles of Falconbridge Ltd were studied. Batch flotation tests were conducted on the stockpile samples and fresh ore samples to explore the effect of stockpiling on grade-recovery performance. Head grade and particle size distribution of the samples from stockpiles were adjusted so that the samples compared are similar to each other. In additional tests, fresh ore samples were blended with stockpile samples at various percentages, representing 27.4, 50.2 and 81.5% of stockpile samples.The samples from stockpiles produced inferior nickel grade-recovery curves compared to fresh ore. The poorer grade-recovery performance was attributable to two factors. First, a significant dilution effect was observed due to the nearly complete flotation of pyrrhotite. Secondly, while pyrrhotite from stockpiled ore became highly floatable, the same stockpiling conditions caused nickel losses that were attributable to non-floatability of some pentlandite.In the case of blending, there was generally insignificant difference in the nickel grade-recovery between fresh and blended samples when the blending cases involved 27.4 and 50.2% stockpile samples. However, an increase in pyrrhotite recovery was observed for both blending cases. At 81.5% blending case, degraded grade-recovery was significant primarily due to the nearly complete flotation of pyrrhotite. There was a small, but noticeable amount of nickel loss for this case. However, for lower ratios of blending this loss was negligible.The increase in pyrrhotite recovery was partly attributed to its activation by Cu and Ni ions. Formation of a significant amount of elemental sulphur was also apparent from analysis of stockpiled samples. It can be concluded that pyrrhotite is mildly oxidized under stockpiling conditions while part of the pentlandite undergoes a more severe oxidation."

Jan 1, 2006

By R. B. Fermor

"AbstractAttention is drawn to the ventilation problems arising from the use of diesel vehicles underground, especially in view of the fact that diesel fumes in combination with other pollutants may be more harmful than diesel fumes alone or the other pollutants alone.Means for minimizing the harmful effects of using diesels underground are listed, and the quantities of air' required in mines in which diesel-powered vehicles are used are discussed. Mines are classified in three categories on the basis of severity of ventilation problems, and statistics are given for these categories.Details of the various components contributing to total ventilation needs are given, and the ventilation needs of individual mines in the three categories are listed. A description is given of the principles according to which main ventilation coursing is planned and the selection and siting of main fans is discussed.General Considerations in the Use of Diesel-Engined Vehicles UndergroundIN ORDER to reduce physiological hazards, present and latent, to workers in mines in which extensive use is made of diesel equipment underground, it is important that mine ventilation systems reduce the concentrations of rock dust, diesel fumes and particulate matter as rapidly as possible to an acceptable level in all parts of the mine.There is some evidence that the long-term effects of a combination of the above pollutants are greater than those of anyone of them alone, which makes the problem even more pressing."

Jan 1, 1977

By Christian Bourcier

La méthode d?exploitation traditionnelle de la mine est le chantier chambre-magasin. Cependant, lors de l?exploitation d?un chantier, nous avons été confrontés à un problème de soutirage. Le minerai abattu est resté accroché à l?intérieur du chantier ce qui nous obligea à soutirer environ 200 wagons, représentant 700 tonnes. Suite à l?ampleur de la situation, nous avons décidé de finir l?exploitation du chantier par la méthode sous-niveau long trou retraité. Cette première expérience de récupération de piliers ayant été réalisée avec succès, nous avons décidé de continuer avec deux autres récupérations de piliers afin de pouvoir augmenter notre expertise autant au niveau technique qu?au niveau économique.

Oct 1, 2001

By Abdelkabir Maqsoud

Different management options and rehabilitation strategies are available for mine wastes that produce acid mine drainage (AMD). One of them consists in building a cover with capillary barrier effects (CCBE) on the tailings to limit the availability of oxygen, an essential component of the chemical reactions leading to the generation of AMD. Prior to cover construction, a monitoring strategy must be established to evaluate the response and performance of the cover system. The key parameters to monitor should include matric suction and volumetric water content in the CCBE, oxygen flux (and/or oxygen concentration) through and below the cover, and the main meteorological parameters for the impoundment. In this paper, different techniques available to measure the targeted parameters are described and their main properties are given. Recommendations (based on existing cases) on the location and the number of monitoring stations and on the measurement frequency for each monitored parameter are also proposed.

May 1, 2007

By J. E. Gill

Introduction During the past summer, detailed geological mapping was extended to cover the entire group of 31 claims owned by Waite-Ackerman-Montgomery Mines, Ltd., and considerable new information was revealed by development and exploratory work underground. These new facts provide a more complete view of the lithology and structure of the area than has heretofore been available. They also necessitate revision of certain interpretations presented last year by Peale (l), and have served to straighten out some of the problems suggested by Porritt (2). The purpose of this paper is to outline in a broad way the relations as now understood and to discuss in detail certain points which should be of interest to members of the Institute. Maps and records by the mine staff have been freely used in arriving at the interpretation presented in the following pages. The writers are especially indebted to Mr. R. V. Porritt, the mine manager, with whom many of the problems touched upon were discussed on the ground and whose intimate knowledge of the geology of the underground workings aided greatly in testing various hypotheses. The writers have profited greatly, also, from close association with Dr. W. F. James during the course of the work. Permission to publish the included data has very kindly been given .by the management.

Jan 1, 1932

By D. W. Hendriks, C. Daoust, K. V. Konigsmann

"The concentrator of Mattagami Lake Mines Limited commenced operation in 1963. It had been designed with instrumentation proven at that time. New control techniques were added in subsequent years.An on-stream X-ray analyser was installed in 1968. It provided circuit analyses for six years without the aid of a computer. In late 1974, control of the flotation circuit by computer was incorporated into the system. Flotation efficiency improved considerably, zinc"" recovery increased by one percentage point and concentrate grade by four-tenths of a percentage point. Reagent costs decreased modestly through reduction of copper sulphate consumption."

Jan 1, 1976

By Wendy L. Naysmith

This paper deals with the various options considered and factors that influenced the final selection of the headframe, shaft layout and hoisting systems required at the Impala No 16 Shaft in order to hoist both the required 3 Mt of ore per annum, and transport men, material and equipment between the surface and the underground workings to a depth of 1640 m. The layout and construction method used for what is at present the world?s tallest concrete headframe is discussed together with the integrated hoist room foundations designed to suit multiple mechanical and electrical hoist supplier?s solutions. The mechanical components of the two tower mounted 6,5m 4 rope Koepe hoists and deflection sheaves and their layout is dealt with in detail. Various features of the bearing type, brake units and brake control system are also discussed. Installation of the mechanical and electrical hoist equipment in the headframe took place during the sinking phase of the project and placed severe restrictions on the use of the heavy lifting facilities. This required a well-managed and systematic approach to delivery of the hoist components and associated equipment, as well as close co-operation between all contractors on site.

Oct 1, 2010

By Olli Haavisto, Juha Timperi

"Accurate on-line assays of mineral slurries are the basis for effective operation of flotation circuits. Typically the elemental content measurements are obtained by an X-ray fluorescence (XRF) analyzer, which samples the process lines and performs the analysis concurrently line-by-line. For a more frequent measurement of each slurry line the XRF measurements can be complemented with reflectance spectrum information. In reflectance spectroscopy the absorbance properties of the slurry in the visible and near-infrared wavelength range are analyzed. The advantage of reflectance spectroscopy is that measurements can be obtained quickly and simultaneously from several slurry lines. However, since the shape of the spectrum is only indirectly affected by the slurry elemental contents, frequent calibration of the measurement against the XRF analyzer is necessary. This study elaborates the combination of reflectance spectrum analysis with XRF. Results of laboratory tests for different slurries are presented and the operation of the system in a copper-zinc flotation plant is demonstrated.IntroductionElemental analysis of mineral flotation slurries is the most important factor in evaluating the performance of concentration processes. Timely on-line assays are also used as the basis for controlling the circuits and ensuring that the grade and recovery targets are reached. X-ray fluorescence (XRF) is the dominant technology in on-line elemental slurry analysis, and typically centralized XRF analyzers are used. The advantage of a centralized analyzer is that one measurement probe can be used to acquire the data from several slurry lines. This reduces the overall operating cost of the system when compared to distributed analyzer system design with several measurement probes requiring maintenance and spare parts. Slurry samplers are installed in the interesting process flows and representative sample flows are brought to the analyzer, where the slurry is further sampled and measured consecutively by the XRF analyzer. Due to the centralized structure of the analyzers and consecutively measurement of the sampling lines the sampling interval per slurry line can be relatively long. In larger concentration plants with several sampling lines a typical assay interval is in the range of 10-20 minutes."

Jan 1, 2016

By I. Nakatsugawa

Chemical conversion coating is a process to create thin oxide/hydroxide film containing several inorganic/organic compounds by way of chemical deposition reaction. In case of the application to Mg mobile electronic housings, the film should possess a good electric conductivity while keeping adequate corrosion resistance and working as a paint base. The use of toxic/hazardous chemicals is strictly prohibited from the environmental aspects. This paper describes the recent trend of conversion coating used for Mg electronic housings and analyzes critically from the point of surface technology. The importance of cleaning process and understanding of surface microstructure are particularly emphasized with several experimental results.

Jan 1, 2006

By R. Simkus, J. K. Gowans

Polaris Operations, a Cominco Ltd. lead-zinc mine, is located on Little Cornwallis Island, Northwest Territories, at Latitude 75°23' N and Longitude 96°75' w. When the Polaris Mine went into operation in late 1981, it became the world's most northerly base metal mine.The Polaris Concentrator, housed in a unique process barge, is a basic lead-zinc concentrator where flotation is used to produce the lead and zinc concentrates.The paper describes the ""coarse lead"" flotation feature incorporated in the concentrator flowsheet and describes the start-up problems and continuing operation of this circuit.

Jan 1, 1984

By J. P. Dick

THIS paper is a description of the milling practice and metallurgy at the Moneta Porcupine mine, Timmins, Ontario. The results obtained with an all-cyanide circuit and later with flotation followed by cyanidation are described. The ?investigation which prompted the various changes in milling practice have also been dealt with. Moneta ore is possibly the most refractory now being milled in the Porcupine district. This is due to the ultra fine state in which the gold occurs and to its intimate association with pyrite. No doubt there is ore of similar characteristics on the neighbouring properties but it probably forms only a small portion of the tonnage being mined, whereas at Moneta the bulk of the ore requires an extremely fine grind to liberate the gold. The fineness to which an ore can be ground economically has gone far beyond what was thought to be the limit only a few years ago. Formerly, a set of standard screens was all that was required to measure the fineness to which an ore was ground. At present, the Haultain infrasizer is practically indispensable, and the nominal micron has become a familiar unit of measurement to all those dealing with the problems of fine grinding.

Jan 1, 1941

By B. K. Gorain, A. W. Stradling

"The traditional metallurgical scale-up techniques for flotation plants are based on lumped flotation rate constants, dimensionless hydrodynamic numbers and the use of safety factors. Once the plant has been designed, the flotation principles that govern scale-up play almost no role in the optimization of the circuit to meet its metallurgical targets. This deficiency can potentially lead to a plant design incapable of meeting its targets, especially when circuits incorporate large flotation cells. This paper demonstrates the application of the k = PSbRf model in providing a suitable framework for flotation modelling, scale-up and circuit optimization, thus presenting an integrated approach to the problem. Studies were conducted at Teck Cominco’s Red Dog concentrator to characterize cell hydrodynamics, gas dispersion properties, froth flow behaviour, entrainment and ore floatability to obtain the key data necessary to develop a model for the flotation circuit. The findings of these studies are presented in this paper, which provide valuable insights into the modelling and optimization of the Red Dog flotation circuit. IntroductionThe traditional methodology for flotation scale-up and plant design is based on the ruleof- thumb with safety factors and dimensionless hydrodynamic group similitude considerations. With the recent trend toward larger flotation cells with volumes of 150 m3 and greater in concentrators, the problem of scale-up has become even more acute. The scale-up factors that may have been tolerated on smaller cells are not applicable to larger cells. The transportation of froth in these large cells adds further complexity to the problem. Arbiter et al. (1980) foresaw this problem and pointed out that if scale-up were attempted by rule-ofthumb and trial-and-error, the probability of failure would then increase with scale. This problem is confounded by the fact that the design and scale-up considerations used for a new flotation circuit play almost no role in optimization of the circuit to meet its metallurgical target. This results in a plant design, which may be incapable of meeting its metallurgical targets. There have been several instances where new concentrators have required significant circuit modifications and additional capacity to achieve design targets."

Jan 1, 2003

By Rajiv Kalra, Ji Jiangang

"This paper reviews the following aspects of the world’s largest manufactured Grinding Mill’s in terms of diameter and power, along with the world’s biggest shop assembly and trial run of the mills delivered to Sino Iron Magnetite Project in Australia.1. An overview of the basic flow sheet of the Sino Iron (Magnetite) Project located in Australia2. An overview of in-house designed CITIC Heavy Industries 12.2 m (40ft) F x 11 m(36ft) LG – 28MW AG mills including FEA and major components3. In-house manufacturing at CITIC-HIC work in Luoyang China of all major components for 6 off Ø12.2 m(40ft) AG mills and 6 off Ø7.9 m(26ft) x 13.6 m(44.6ft) LG – 2 x 7.8 MW Ball Mills4. Major aspects of design and preparation of the biggest shop trial run of Ø7.9 m(26ft) x 13.6 m(44.6ft) LG Ball Mill witnessed by international EPCM’s and clients in July 2009.5. Major aspects of one piece assembly of 1300 tonne rotating element of the Ø12.2 m(40ft) x 11 m(36ft) LG AG Mill and Ø7.9 m F (26) x 13.6 m(44.6ft) LG Ball Mill at the port of the export China and transport to Australian Port and then to site.6. An insight to unique installation methods used for Ø12.2 m(40ft) and Ø7.9 m(26ft) rotating element lifting on the mill foundation in one piece assemblies.7. CITIC Heavy Industries present capability for in house design and manufacture of Grinding Mills up to Ø13.7 m (45 ft) with 35 MW Gearless drives and Ø12.2 m(40ft) with 2 x 10 MW Geared Mill drives"

Jan 1, 2012

By Oy Leuangthong

The McMurray formation in the Athabasca oil sands deposits of Northern Alberta is part of the world?s second largest proven crude oil reserves. The formation is characterized by stratigraphic layers that correspond to three different depositional environments: Marine, Estuarine and Fluvial facies. Resource estimation for oil sands has traditionally relied on polygonal and inverse distance schemes. These techniques are simple and straightforward in practice, but they do not permit reliable uncertainty assessment. This paper describes the modeling of the McMurray formation using modern geostatistical techniques. Geostatistical modeling should be performed within homogeneous geological facies. The methodology for geostatistical simulation within each of the identified facies involves: (1) assessing the most appropriate stratigraphic transformation for optimisation of the correlation structure, (2) determining representative distributions with declustering and debiasing techniques, (3) modeling spatial continuity of the bitumen grade, fines grade, water saturation and other petrophysical variables, (4) performing estimation and cross validation as checks against simulation results, (5) performing simulation for uncertainty quantification of bitumen and fines grade, and (6) model checking of simulation results against the input data and comparisons against the kriged models. These steps are described in detail. The application of these models for uncertainty quantification in support of resource classification is also discussed.

May 1, 2004

By Seppo Lähteenmäki, Pertti Koivistoinen, Jaakko Levanaho

"This paper describes the benefits and disadvantages of fully autogenous grinding when compared to grinding with steel grinding media. The study is a real case study based on a low tonnage, high grade mining project in a remote location in a developing country. The study compares the capital and operating costs of using either SAG mill, Ball mill, Crusher (SABC) or fully autogenous (AG) grinding circuits and produces an economical analysis of the project for both options. The economics have been developed for the overall project, including mining, processing, environmental and the infrastructure as well as for the additional cost of constructing a fully autogenous grinding circuit instead of the original plan of a SAG Mill, Ball Mill circuit.The paper also describes the development of the autogenous grinding circuit at Outokumpu Oy, Pyhäsalmi mine. This experience was used to design the autogenous grinding circuit for the case study. Pyhäsalmi Concentrator has over 30 years of experience in operating autogenous grinding circuits and therefore provides a sound base for the new circuit design.INTRODUCTIONGrinding of ore using steel grinding media is currently the most commonly used method in the mining industry. Autogenous grinding, ore replaces iron media, is also common especially in Europe and Africa. Iron ore industry in North America uses autogenous grinding in primary and/or secondary stages extensively. In gold, copper and other base metal industries, autogenous grinding is not as common, although there are operations where pebble grinding is or has been used in the secondary grinding stage. There are many variations of autogenous grinding in use in the mining industry. These variations include different mill sizes, mill length to diameter ratios, ore lump sizes, screening and pebble crushing configurations."

Jan 1, 2000

By L. Gonzalez-Sardi, W. McCombe, M. Pearson

Pressure oxidation is increasingly being used for processing refractory sulphide ores and concentrates because it offers highly effective base metal and precious metal extraction while minimizing elemental sulphur, arsenic & mercury emissions. Yet pressure oxidation processes introduce new safety concerns and process risks as demonstrated by a number of safety incidents over the last 20 years, including overfilling, oxygen-metal fires, nozzle/sparger failures, and uncontrolled pressure relief events. Chemical Process Safety regulations in the United States and Canada mandate that companies constructing or operating chemical process facilities perform a rigorous hazard and risk analysis based on either ANSI/ISA-84.00.01 or IEC 61511 safety standards to determine the level of protection required for each hazard in the plant. This paper describes the application and implementation of three (3) unique safety instrumented systems developed by Hatch for ensuring the safe operation of three different pressure oxidation processes.

Jan 1, 2014