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By J. Butra

The underground research presented in this paper was carried out in the two Polish copper mines: Rudna and Polkowice-Sieroszowice. The aim of the research was to determine stress field parameters. The measurement method and measuring positions are described as well as the measuring technique adapted to the geological and mining conditions of the Rudna mine and the Polkowice-Sieroszowice mine. The identified values and directions of principal stresses and horizontal stresses and their importance for optimization of mining operation and safety improvement are discussed.

Aug 1, 2013

By P. Condori

Palabora Mining Copper (PMC) has two autogenous mills that have been in operation since 1976. The mills were originally designed to treat 30 000 t/d of open cast copper ore in a closed circuit with cyclones. As the ore body went deeper the open cast method of mining was changed to block caving, a consequence of this was the dolerite content (hardest barren material) increased significantly, increasing the production rate of pebbles and thus reducing the milling capacity. In order to cope with the increased ore hardness and to increase mill capacity, a second ball milling stage and pebble crushing were incorporated to the circuit. The above actions created new challenges to the circuit operation and bottlenecks in different areas of the milling circuit. This paper reports the holistic work performed on the Palabora autogenous milling circuit including the implementation of a mill constraint control scheme, the implementation of a pebble removal system from the circuit and a new circuit configuration. The achieved plant stability and increment of ore throughput are also reported in this paper.

Jan 1, 2012

By P. Tarassoff

Extractive metallurgy is concerned with the winning of metals from their ores and concentrates. It is therefore not unexpected that extractive metallurgy in Canada has always been closely linked with mining. The discovery and exploitation of new orebodies has provided the impetus for the building of many of our smelters and refineries - past and present - and for the development of new metal extraction processes. The purpose of this paper is to provide a brief overview of those early metallurgical developments, and to highlight the continuing expansion and diversification of the Canadian metallurgical industry.

Jan 1, 1999

By J. A. Allan

"The history of the development and application of controlled recirculation systems in U.K. collieries is traced and the theory behind such systems briefly examined. Specific applications for dealing with dust and dust/heat problems in headings, for which practical experience is currently available, are described. Consideration is given to the special features which these systems introduce in the underground situation and to the essential safeguards which are required for their safe use.IntroductionRecirculation of air is a commonly used technique in genera l ventilation and air conditioning practice, but has always been regarded with some suspicion for mining applications. This is perfectly understandable in view o f the hazardous conditions which can occur with dangerous forms of recirculation in mines. However, certain controlled recirculation techniques can offer advantages, particularly in the field s of dust and climate control in headings, provided that they are designed, Installed an d managed with full comprehension o f all aspects of the system and always bearing in mind that from the point of view of serious firedamp ignition risk, headings are potentially the most hazardous places in coal mines.BackgroundProbably the first recorded use of deliberate recirculation in British collieries was reported by Lawton in 1933. This researcher described trials, undertaken under the auspices of a national committee on ""The Control of Atmospheric Conditions in Hot and Deep Mines"", involving attempts to increase the velocity, and thereby the cooling power on hot faces, by means of simple recirculation systems using fans and ducts delivering recirculated air in the opposite direction to the normal face airflow. No significant cooling advantage was obtained and there is no subsequent record of this work being continued. During the discussion on this paper, there was considerable disbelief that fire damp percentages had not increased significantly when air was recirculated, but apparently no attempt was made to establish why this should be. It is of interest to note that J. Ivon Graham, one of the contributors, recommended that recirculation should be tried in stone headings for the control o f dust, as he believed that ""there may be scope for recirculation and filtration of the air under certain circumstances in such headings"". This idea was not developed for another forty years."

Jan 1, 1983

By Raphaël Mermillod-Blondin, Claude Bazin

"Sampling is an important step for ore body evaluation and daily plant material balances. The Gy’s equation is regularly used to assess the size of the samples to be collected and to estimate the reproducibility of the collected samples. The equation works well for iron and base metal ores but seems to produce pessimistic estimates of the gold content reproducibility for gold ores. A model is proposed to simulate the division of samples using a standard splitter and discrepancies are observed between the Gy’s equation predictions and simulated samples reproducibility for crushed gold ore. Results of the simulation show that sampling a pile of ore crushed to -2 mm should lead to more reproducible gold content than it is observed in practice and predicted by the Gy’s equation.INTRODUCTION With current gold prices above $1400 per troy ounce operators seek for new economical ore bodies. The metallurgical evaluation of an ore body is one of the numerous steps required to justify the investment for the development of a gold mine. Metallurgical testing requires to sample the ore body and to prepare the ore sample for the grinding and separation tests. The preparation implies crushing the ore usually to less than 2mm and its division into batches of a given weight for subsequent processing. For gold ore testing a batch of crushed ore is ground in a laboratory mill and leached using cyanide. Gold recovered in the solution is used as an indicator of the ore processing amenability. One difficulty associated with ore testing is due to the reproducibility of gold content measurements of the feed sample. According to the Gy’s equation (Gy, 1979; Morisson, 2009) the division of a 20 kg batch of -2 mm ore containing 5 g/t of gold into batches of 1 kg may lead to batches containing 5 ± 5 g/t of gold. For this reason the gold content of a feed sample is usually back calculated from the assays of the solution and solids residues of the leaching process. However, these two assays may contain measurement errors that can propagate through the calculation of the gold recovery. The use of the feed assays as a redundant information could add robustness in the evaluation of ore amenability to processing. This paper discusses the problem of sampling reproducibility for a gold ore. The analysis is carried out with reference to the Gy’s equation for the sampling of particular materials."

Jan 1, 2012

By John De La Vergne, Morri Medd

"This paper describes the sinking of a circular concrete ventilation shaft through 110feet of water-bearing overburden. The brine circulation freezing method was used to stabilize the walls during excavation. In order to take advantage of the cold winter weather, a custom-built heat exchanger (natural radiator) was installed in place of the standard mechanical refrigeration plant.IntroductionIn the late fall of 1979, Les Mines Selbaie awarded a contract to the firm of 1.S. Redpath Limited to sink a ventilation shaft on its property in northwestern Quebec. The shaft was to be sunk through 110 feet of water-bearing overburden and approximately 90 feet of rock to a final depth of 200 feet below surface. The water table was measured at 16 feet below the surface elevation.After examining the soils report and diamond drill core from the shaft area, Redpath came to the conclusion that freezing was the best way to stabilize the overburden for sinking. LocationThe mine site is 420 statute miles due north of Toronto, just east of the Ontario/Quebec border (Fig. 1). Access to the site is provided by a development road built by the Quebec government from the Matagami/lames Bay Highway. History of Ground Freezing In the Mining IndustryIn 1862, shortly after the development of mechanical refrigeration, a mine shaft was sunk through an artificially frozen water-bearing formation in the United Kingdom. The first application of ground freezing in North America was for a Michigan iron ore shaft in 1888. Since that time, the freezing method has been used to sink hundreds of shafts throughout the world. Its best known application was to sink sixteen shafts through the Blairmore Formation in Saskatchewan.The same method has been used in every case. It involves chilling a calcium chloride brine solution and circulating the brine in concentric pipes, spaced between 3 and 6 feet around the shaft perimeter and usually 4 to 5 feet from the limits of the proposed shaft excavation."

Jan 1, 1982

By R. Filippone, Donald Leroux, Colin Hardie, G. Leichtle, Cesar Gomez, Jim A. Finch

"Bubble surface area flux (Sb) is the surface area of bubbles per unit time per unit cross-sectional area of flotation machine. The units are: (m2 bubble surface/s)/(m2 cell) or s -1. For bubbles of mean size db (m), s b = 6-Qg/A db where Qg is the gas rate (m3/s), and A the cell cross-section (m'). This parameter is now receiving wide attention as the possible key machine variable in flotation diagnosis and modelling. The concept is described and the potential use of sb is illustrated by work on flotation columns and mechanical cells. In column flotation of recycled paper, the dependence of ink recovery on s b was the same regardless of size of column or type of sparger. In mechanical cells, it has been established that the rate constant is related to Sb independent of impeller type.The use of s b is limited by the problem of measurement, primarily that of estimating db. A prototype probe designed to estimate db (and hence sb) based on conductivity measurements is described. Exploratory work with the probe in a mechanical cell suggests the promise of making estimation of s b routine.INTRODUCTIONFlotation is the result of interaction among variables associated with the feed particles, chemistry and the machine (flotation cell). Trying to isolate the effects of each aids in process diagnosis and is at the centre of attempts to model flotation. The machine variables that have been investigated include the air flow number, the power number and specific power (Harris, 1976). None have survived as the basis for predicting flotation response perhaps because they did not include directly the properties of the bubble swarm (or dispersion). Recently, Gorain (1 997) explored the relationship between the flotation rate constant and various ""gas dispersion"" parameters notably: superficial air rate (Jg = Qg/A, where Qg is the volumetric gas rate and A is cross-sectional area of cell), bubble size (db), gas holdup (Eg, i.e., the volumetric fraction of a cell occupied by gas) and bubble surface area flux (sb = 6.Jg/db). Of them all, Gorain et al. (1997) conclude that the latter, the surface area flux, correlated best with the flotation rate constant. This concept was adopted from column flotation where it was used to estimate, among other factors, the maximum amount of gas that could be injected (Finch and Dobby), 1990). Let's start by reviewing the concept. Following that some examples of where the concept has been applied will be described to illustrate the current interest and finally we will consider how to measure the surface area flux."

Jan 1, 1999

By C. Siac

"It is a widely held view that in the 21st century, the mining industry will be dominated by a relatively small number of large companies, truly global in scope and internationally staffed (Gooding, 1997). Interestingly enough, most of the exploration and exploitation activities are being carried out by junior and major mining companies from common law jurisdictions in civil law countries, in particular in Latin America, where in recent years, the region has ranked first as a destination for exploration dollars, thanks to the reforms undertaken by some countries to amend their legal framework to attract foreign investment. From a lawyer’s point of view, this is where the main challenge lies: how to bridge the gap between the two legal systems.In order to avoid pitfalls, common law lawyers should be more diligent and proactive when dealing with civil law jurisdictions, given the different systems of law, standards, traditions and customs. Common law lawyers cannot be expected to be well-versed in civil law but they should not be completely unfamiliar with it either. A balance should be struck to ensure clients’ needs are professionally taken care of and that common law requirements and standards are met."

Jan 1, 2003

By Rodolfo Espinosa

"Industrias Peñoles, S.A. de C.V. in Mexico, has nine mining operations, six managed by Peñoles (base metal mines) and three managed by Fresnillo plc (precious metal mines). Seven of the operations use flotation and the other two are heap leach operations, one for gold and the other one for copper.This paper gives a brief introduction of Peñoles, shows mine locations and describes the main process characteristics of each concentrator. It also presents four of the new operating practices that were implemented over the last four years to improve the economics of the mining operations. These include (1) the use of centrifugal gravity concentrators to increase the recovery of gravity recoverable gold (GRG) and silver (GRS), (2) the use of expert systems to reduce process variability while increasing grades and recoveries, (3) the application of the Six Sigma methodology to key projects to ensure success and personnel development and (4) the use of water chemistry fundamentals to identify chemistry problems and design adequate solutions for improving grades and recoveries.INTRODUCTIONPeñoles was founded in 1887. It is a mining group with integrated smelting, refining and chemicals producing operations. Peñoles is the world largest producer of refined silver and metallic bismuth, the leading Latin American producer of refined gold and lead. It is amongst the world leading producers of refined zinc and sodium sulfate.Peñoles operates and controls six underground mines in Mexico and is the largest producer of zinc and lead of the country. It also produces copper concentrates and cathodes. Through its 77.1% equity stake in Fresnillo plc (a London Stock Exchange listed company); Peñoles is also a significant producer of gold and silver. Fresnillo plc operates three precious metal mines in Mexico. While Fresnillo is the world largest primary silver mine, Ciénega and Herradura are two leading gold mines of Mexico. Figure 1 shows a map of Mexico indicating the locations of the Peñoles mines. The main process characteristics of each concentrator are listed in Table 1."

Jan 1, 2011

By P. Maltais

Over the last 10 years, Computer Aided Design, Finite Elements Analysis and field testing of prototypes have enabled the cycling industry to grow and to significantly improve its products. However, today's cyclists have become more and more demanding, making these classical design approaches almost obsolete. Devinci understood that problem four years ago and fully revisited its design approach; to offer bicycle frames better suited to real life riding, one must fully know those real life conditions. In partnership with the University de Sherbrooke, Quebec, Canada, Devinci then developed a bicycle enabling them to measure the actual load applied on a bicycle frame in real-time for real riding conditions: the instrumented bike. Today, Devinci uses its instrumented road and mountain bikes, combined with virtual prototyping and laboratory testing capabilities to develop better bicycles, faster.

Jan 1, 2006

By E. Burdukova

Long-chain primary amines are utilized as collectors in potash ore flotation. Krafft temperature of long-chain amines in brine is about 100 °C, and this makes such amines practically insoluble in brine at room temperature. When dodecylamine, melted at 70 °C and dispersed in hydrochloric acid (or acetic acid) aqueous solution, is added to a KCl-NaCl saturated brine at room temperature, the amine precipitates. The experimental results demonstrate that the precipitating amine hydrochloride particles are selectively abstracted by KCl particles, but not by NaCl particles.

Jan 1, 2009

By R. M. Berry

A brief outline of refining methods used to (1) upgrade yellowcake to nuclear purity and (2) convert the uranium to the chemical and physical forms required by the fuel fabricators is presented. The uranium hexafluoride (UF6) production facility now under construction at Eldorado, Port Hope, is discussed. Technological improvements in uranium refining are considered.

Jan 1, 1969

By John A. Dresser

At a meeting of the Montreal Branch of this Institute in the autumn of 1928, the Honorable J. E. Perrault, Minister of Mines for Quebec, announced his intention to enlarge the Bureau of Mines of Quebec by the addition of a Division of Geology. The announcement further stated that the geological work proposed should be begun in the following field season, and that it should be on a substantial scale of not less than six field parties. The announcement was received with enthusiasm and much encouragement was held out for the success of the effort. It has been thought that the present meeting would be a suitable occasion to present a report of progress of this Division for the three years that have since elapsed. History This, of course, is not the first geological work to be undertaken by the Bureau of Mines. Prior to the establishment of the Division of Geology, the Bureau of Mines had not been unmindful of the need of geological research, but it had always lacked the means necessary to any sustained work. For more than 25 years the late J. Obalski was the Superintendent and the sole occupant of the Bureau. Yet, even then, Obalski, besides routine visits to mining districts, made a few exploratory trips along the north shore of the St. Lawrence river and one to Chibougamau, but without the equipment necessary to effective results.

Jan 1, 1932

By Lynne Bowen

"On the da y shift in Number One Mine at Nanaimo on Vancouver Island, on May 3, 1887, William Griffiths, a coal miner with many years experience, fired a shot to advance the face of the crosscut. A flame ran out for a distance of fifteen feet along the roof and then extended up the slope for ten to twelve feet, and although many would have called this a blowing out shot, Griffiths said it was just a feeder. ""A blower"", he said, ""would have caused an explosion."" 1There was no explosion. Griffiths reported gas and the area was cleared for three hours and then work resumed. When the shift changed at 3:00 p.m., the fireman reported all places clear of gas and the ventilation good.2The ventilation in Number One Mine was the best anyone had ever seen. The air in the mine was almost too cold. The current was so strong that it sometimes blew out the flame on the miners' fish oil lamps. It delivered five to six hundred cubic feet of air for every man and animal working in the mine. The law required only one hundred cubic feet 3The miners considered Number One to be relatively safe. The manager was proud of the mine and its up-to-date equipment"". Recently, there had been reports from France and America about the explosiveness of coal dust, but the manager did not think his mine was sufficiently dusty to be dangerous.5 The dust lay thick on the floor of the mine. Sometimes when a shot was fired the dust rose in great clouds. When a miner was shovelling it, the dust would billow up and be carried off by the current of air. The dust was also in the roof and in the stopings, put there intentionally to fill up the spaces and prevent the accumulation of methane gas."

Jan 1, 1992

By F. Rashchi, N. Naseri Joda

Recycling of electronic wastes is an important subject both from an environmental point of view and also the recovery of valuable materials. In this research, PC board scraps were leached to recover Cu, Ag, Au and Pd. Due to the high cost of the shredding process and to avoid secondary pollution from odors and dusts, board scraps were cut into 5X5 cm2 pieces. To determine the most effective leachant, aqua regia, nitric acid, hydrochloric acid, ammonium persulfate and potassium persulfate were tested. The effect of the leaching parameters, the leachant concentration, temperature, leaching time and liquid to solid ratio were studied and optimized using response surface methodology.

Jan 1, 2011

By P. J. Adams

Environmental regulations require means for controlling emissions of SO2 NOx and particulate when burning coal. The combustion of coal in limestone fluidized beds is one of the most promising techniques for the necessary reduction in emissions. Fluidized-bed firing, furthermore, offers potential economies in capital equipment. The world's largest steam generator applying fluidized-bed techniques was built under the sponsorship of ERDA and installed in Rivesville, West Virginia. This paper describes the design and discusses the start-up and development difficulties which were experienced during the period from initial operation to current readiness for commercial operation. Other developments leading to utility and industrial fluidized-bed steam generating equipment are reviewed. The future potential of this promising technique is discussed.

Jan 1, 1979

By Jacques Nantel

"The molybdenite property of Brynnor Mines Limited, Boss Mountain Division (wholly-owned subsidiary of Noranda Mines Limited), is situated approximately 360 miles northeast of Vancouver on the east slope of Takom-kane mountain in British Columbia's Cariboo District. Orebodies at the deposit fall into two categories; quartz breccia, and veins and stringers. The development of the breccia ore zone was started in June, 1964. The bulk of the ore is being mined from the stringer ore zone. The ore-body has been divided into 100-foot stopes and pillars. A sub-level blasthole method is used and the broken ore is handled in drawpoints and scram drifts. The development, drilling, blasting and handling of the ore are reviewed. The future pillar recovery operation is also analysed. The paper is also concerned with a scheduled shaft sinking program."

Jan 1, 1970

By Steve McAlister, Colin Sprake

"Enhanced gravity concentration machines have been applied successfully in the following areas of precious metal recovery flowsheets:1. Primary Grinding Circuits2. Shaking Table Tailings3. Pre-Concentration of Leach Feed4. Flotation Concentrates -•, Flash•, ConventionalAlthough great progress has been made, the ability to produce directly smeltable concentrates still remains elusive. Even without this ability, centrifugal concentrators are finding wideningapplications in precious metal concentration:1) PRIMARY GRINDING CIRCUITSEnhanced gravity concentration technology has largely replaced jigging as the technology of choice in precious metal grinding circuits worldwide. The benefits of using a centrifugal field to concentrate both coarse and fine gold are well documented but the placement of these machines within grinding circuits is still evolving. Conventional wisdom dictates that the best location for enhanced gravity machines is cyclone underflow on account of the elevated grade found in this stream when compared to cyclone feed or overflow. Plant operating experience at both large and small scale indicates that there are compelling arguments to place ENHANCED GRAVITY MACHINES on cyclone feed instead. At least two new plants, presently in the detailed design stage will incorporate gravity circuits that treat mill discharge or cyclone feed, Teck Cominco’s Pogo and Newcrest’s Telfer Expansion.Current Conventional PracticeThe current stream of choice for enhanced gravity concentration within grinding circuits is cyclone underflow although recent information indicates a swing toward cyclone feed. Here are some of the arguments for treating a portion of cyclone underflow:"

Jan 1, 2003

By O. A. Carson

"IntroductionTHE ZINC-BASE die casting alloys in common usage contain approximately 4 per cent aluminum as the major alloy element. In addition, they contain about 0.05 per cent Mg .and may• have a small amount .of copper. These are usually the only •elements intentionally present.Small amounts of some impurities have been shown to have a deleterious effect on the properties of these alloys and therefore the impurities are kept low by starting with '99.99%' zinc.The reasons for holding the aluminum content at 4 per cent are not clear. Some statements appear in the literature that higher aluminum increases the brittleness, but probably the chief reason was the relative price of zinc and of aluminum when 4% alloys became firmly established. At that time, aluminum was three to four times the price •of zinc on a weight •basis. Recent prices, roughly equivalent per lb., make aluminum considerably cheaper than zinc on a volume basis and suggest that increased aluminum content would result in a decrease in the cost per piece due to the lower density of the alloy.Little information could be found in the literature and, therefore, it was decided to determine some physical properties of the higher aluminum zinc-base alloys made from high-purity zinc."

Jan 1, 1953

By J. Guha, A. Gobeil, P. Pilote, A. Tremblay, E. Dimroth

The Mount Bourbeau Lac Berrigan area is located just to the north of the Town of Chibougamau. The axial trace of the Chibougamau syncline borders the northern part of both areas. The area contains Archean rocks of the Roy Group, intruded by the Cummings Complex and the Line Lake tonalite stock. Proterozoic sedimentary rocks occur in a series of outliers. Various Cu, Zn, Pb, Ag, Au and Mo showings are dispersed over the area in a wide range of time and space. Pre-Kenoran (stratiform and stringer) showings related to volcanic activity may be distinguished as well as the syn-or post-Kenoran (vein) types whose nature is imprecisely known. In this area, the stratiform showings occur in the Gilman and Blondeau Formations, whereas the vein type showings occur for the most part in fractures or breccias within or along the contacts of the various sills of the Cummings Complex. Mount Bourbeau is distinguished by the greatest variety of showings as well as the proximal volcanic facies of the Blondeau Formation. A volcanic centre is presumed to lie a short distance north or east of the locality. Locally, the Line Lake stock contains significant silver, molybdenum and gold mineralization. Its role as a metal reservoir, a source of heat for the circulation of hydrothermal fluids and its control of the local tectonic style remains to be determined.

Jan 1, 1984