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By Stephen P. Quin

One of the most prospective undeveloped greenstone belts in Canada, the Hope Bay greenstone belt extends over 80km in a north-south direction and is between 7 and 20km wide. The belt lies on the arctic coast and comprises mafic meta-volcanic and meta-sedimentary rocks that are bounded by Archean granite intrusives and gneisses. The greenstone package has been deformed during multiple events and is transected by major northsouth trending shear zones that appear to exert a significant control on the localization of mineralization. The Hope Bay belt contains a number of significant gold deposits hosted in a typical Archean greenstone belt and which occur in several geologic settings, including shear-hosted, lode-style and breccia-associated. Combined, the deposits host a measured and indicated resource of 1.6 million oz of gold averaging 15.7 g/t plus an inferred resource of 2.7 million oz of gold averaging 12.3 g/t. All deposits remain open to expansion. Exploration in the period 2000-2002 by Miramar includes more than 110,000m of drilling to more fully define the nature of the known deposits, while regional exploration has focused on identifying and evaluating new targets. In carrying out its programs, Miramar uses a number of techniques to improve its chances of exploration success. Activity in 2003 includes 43,000m of drilling focused on expanding resources in the Madrid area, testing the Boston deposit at depth and continuing the hunt for more discoveries. Meanwhile Miramar is advancing one of the deposits towards a production decision, based on a low capital, high return development scenario.

May 1, 2003

By J. A. McLennan, J. M. Ortiz

Nickel laterite deposits are typically formed from tropically weathered mafic-to-ultramafic complexes. The resulting nickel concentration is found within soil horizons and is mineable with regular dozer units. At the time of mining, digging elevations are needed at selective mining units (SMUs) or representative dozer regions (RDRs). Moreover, for mine planning, the costs due to dilution and lost ore require mining elevations to be specified. A conditional simulation approach is used to calculate “optimum” RDR mining elevations. Multiple realizations of the ore base surface are simulated. For a single bottom surface realization, dilution and lost ore costs are calculated over the entire vertical extent of each RDR. The optimum mining elevation is the elevation where the lowest summed cost of “accepting dilution” and “wasting ore” occurs. The reported RDR dilution is the cost of mining the volume of waste located below the bottom surface and above the optimum mining elevation. The reported RDR lost ore is the cost of not mining the volume of ore above the bottom surface and below the optimum mining elevation. For all ore bottom surface realizations, optimum RDR mining elevations and their associated dilution and lost ore costs are calculated and compiled to represent production uncertainty.

Jan 1, 2006

By Simon D. Handelsman

?Artisanalmining ?Application of human energy (e.g. pick & shovel) directly to produce minerals ?majority no technical skills and lack adequate working tools ?Small-scale mining ?Application of modern technology for limited scale mineral production Significance of ArtisanalMining ?15 million people in artisanaland small scale gold mining ?55 developing countries ?Use of mercury damages health of 100 million people

May 1, 2006

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

By T. Peters, W. C. Ferguson

"Shebandowan is about 600 miles west of Sudbury and 50 miles west of Thunderbay close to the trans Canada highway. Shebandowan Lake is about 38 miles long. The ore body is located between No. 1 and No. 2 shafts at the lower end of the lake. The economic mineralization lies between 200 and 2000 feet below. Years ago development of this ore body would probably have entailed draining the lake and using the open pit method to mine the ore.The water of Gold Creek which flows into Lake Shebandowan is representative of all local waters and is very close to rain water in purity. It is obvious that any industrial water discharged would have a measurable impact on the local water. The dissolved solids content is low and consistent with what is normally found in northern Ontario.A Koepe headframe is the only visible evidence of the mine from the lake. The Koepe headframe is esthetically pleasing and quiet in operation. The structure is of concrete to control noise. Noise from ore dumping is controlled by dumping underground to an ore pocket 400 feet below the surface. A 3600 foot conveyor belt carries the ore underground to the mill and is out of sight of the lake and the cottagers. The main objective to all our environmental efforts has been to preserve the natural beauty of the region. The mill is housed in a conventional metal-clad-siding building painted in esthetically pleasing colours. A single service building houses warehouse, dry storage and offices. The area surrounding the mill and service building is paved or grassed and drainage from this area is collected and pumped to the tailings area. Air intake silencers are installed on the compressors which are mounted at the back of the mill. Sound measurements taken on the lake indicate that noise suppression is excellent."

Jan 1, 1975

By François Robichaud

"The Laronde mill has been in operation since 1988. Actual milling rate ranges from 7,000 to 8,500 mtpd. Laronde uses SAG/ball mill grinding followed by copper and zinc flotation circuits. A cyanidation/Merrill-Crowe process recovers the remaining gold and silver in the flotation tails.In 1999, the carbon in pulp circuit was replaced by a Merrill-Crowe circuit in order to cope with a much higher ratio of silver/gold associated with the discovery of the Penna shaft. Marine type diatomaceous earth was used as filter aid in both clarifier pressure leaf filters and recessed pressure filter presses from 1999 to 2005. In 2005, this filter aid was gradually replaced by alpha-cellulose after several laboratory and plant filtration trials. The selected cellulose is considered to be much less sensitive to parameters such as pH and reagent concentration and have increased clarifier and filter press filtration performance. Also, since cellulose is exothermic, replacing diatomaceous earth with cellulose as filter aid in the filter presses has increased calcining and oxidation rates in the calcining ovens since cellulose is exothermic. Finally, better calcining conditions have resulted in energy and reagent savings at the arc furnaces.This paper describes how the filter aid replacement has contributed to increasing productivity and Net Smelter Return of the refinery while reducing worker’s hazards and operating cost.INTRODUCTIONAll Merrill-Crowe circuits in the world are operated with filter aids. For years, the market for precoat filter aid has been dominated by mineral filter aids such as diatomite and perlite. Flowsheet and equipment selection at the Laronde refinery were performed in the late nineties. At that time, some key parameters of the design criteria had clearly identified marine type diatomaceous earth (DE) as the most successful filter aid. Parameters such as reagent cost and availability, clarity of the filtrate solution and good historical filtration performance in other concentrators had designated DE as the best suited filter aid. Pregnant solution processed in the refinery from its start-up through 2001 was fairly stable in flow rate and reasonable in terms of impurity content (cationic and anionic compounds)."

Jan 1, 2007

By Yves Breau, François Robichaud, Jacques McMullen, Pierre Pelletie

"The Expert System implemented at the East-Malartic mill controls a copper flotation circuit while taking into account the profitability of the operation. Treating a copper gold ore, the flow sheet integrates a flotation step followed by cyanide leach circuit. The Expert System calculates the actual net smelter revenue of the flotation circuit, accounts for the operating cost of the cyanidation circuit and defines optimal metallurgical operating targets to optimize the overall economics. To be realistic, probability factors and circuit diagnostic analysis are integrated in the operating target selection. The Expert System has proved to be successful, robust and flexible. It resulted in a copper concentrate grade increase of 1% while maintaining recovery. The use of the expert system also gives plant personnel good training procedures and promotes interaction with mill operator.INTRODUCTIONThe East-Malartic mill is located close to the town of Malartic in North Western Quebec, Canada. The mill was first commissioned in 1938. The flowsheet at that time was a straight cyanidation circuit. The original mill operated in that mode up to the discovery of the Bousquet 2 orebody in 1989 which consisted of a massive copper sulphide ore averaging 0.7% copper and 7 g/mt of gold. Bousquet 2 ore processing required a mill retrofit. Grinding capacity, gravity and copper flotation circuits were inserted prior to the cyanidation circuit in order to achieve 3,200 mtpd capacity at expected recoveries.In 1993, control of the flotation circuit was deemed critical in order to maintain the flotation performance and to reduce cyanide consumption since the copper sulphide contained in the Bousquet 2 ore is a high cyanide consumer (50% bornite). (McMullen, 1999) As a result, the implementation of advanced control strategies in order to increase the metallurgical profitability of the plant and to reduce the operating variability between operators was the most rational alternative. In 1994, Corem was chosen to perform the plant audit and to write the first set of rules. The on-line control strategy was started up in 1995. In 1996 and 1997 the Expert System was shutdown because of an extreme change in the ore coming from the milling of Bousquet #1 ore and the departure of the projects engineer. In 1998, the system was restarted and the results were impressive. Furthermore in May of 2001 a patent was issued for the control strategy. (Breau, 2001)"

Jan 1, 2002

By Richard Mcivor, Largo Albert

"Inco Limited has operated aluminum mine shaft conveyances since 1968. Aluminum conveyances are used where the hoisting in system requires lightweight conveyances to maintain the hoist rope safety factors and mine hoist rope pulls as dictated by government regulations. Inco Ltd. currently has 20 skips (including spares) operating in the Ontario Division mines. The main problems encountered are with galvanic corrosion between dissimilar metals and metal fatigue. This paper will highlight some of the problems encountered and illustrate methods utilized to overcome the problems and improve the conveyances performance.IntroductionAluminum mine shaft conveyances have been in use at Inco Limited's various Sudbury district mines since 1968. All of the conveyances currently in use are skips used for hoisting mine ore and rock. Inco had an aluminum quick change Kimberley-type skip and cage in operation at its Totten Mine in the early 1970s, but this mine is no longer in operation and no further comment will be made.The primary reason why aluminum conveyances are chosen over conventional steel conveyances is because of their light weight. Typically an aluminum conveyance will weigh about 60% to 70% of a steel conveyance of similar design. The lighter weight conveyances will allow higher payloads to be used and still maintain the statutory hoist rope factors of safety. It must be remembered that increasing the payload will increase the power required to raise the load and the hoist will have to have the necessary horsepower for the increased payload or the system will be overloaded.The front dump (Rola-chute) skips are of the bail-less design, i.e. the box structure also supports the load and has the shaft guide shoes attached directly to the side of the box structure. The Copper Cliff North Mine and South Mine skips have a joint in the centre of the conveyance and are installed in the shaft in two sections and connected with pins. This feature allows very long (42 ft) skips to be used in areas where a one-piece bail-type conveyance could not be installed. It is not practical to make sectionalized bail-type conveyances"

Jan 1, 1988

By John H. Fowler

"Most of the aggregate used in Nova Scotia is produced from numerous glaciofluvial and ice-contact deposits scattered throughout the province. Production from bedrock sources is increasing, with most of the coarse aggregate used in the Halifax-Dartmouth area coming from quarries operating within the metro area.A recently completed provincial sand and gravel inventory mapping program has identified some ""resource-poor"" areas where comprehensive aggregate evaluation programs are underway. Although some areas of the province are experiencing aggregate supply problems, large volumes are exported to markets as far away as Bermuda.IntroductionThe Nova Scotia Department of Mines and Energy has been involved with aggregate resource studies for several years, although sand, gravel and crushed stone are not designated as minerals under the Mineral Resources Act of Nova Scotia. Our role has been to provide the aggregate industry with resource data as well as provide similar information to governmental agencies involved with municipal planning, water resource studies and environmental protection regulations. Several private consulting firms use the information in many of their site development studies.We became involved with aggregates in a rather roundabout way. Several years ago, an outcry from inhabitants of a small coastal community over the removal of sand and gravel from a local beach moved the provincial Department of Lands and Forests to take action to protect provincial beaches. We were asked by the Department to provide information and to suggest alternative sources here operators extracting sand and gravel from beaches could relocate. This request initiated an aggregate inventory survey in southeastern Cape Breton, which was later extended to cover the entire province. The initial provincial sand z and gravel inventory survey provided a series of 1:50,000 maps showing the distribution of sand and gravel deposits in the province."

Jan 1, 1982

By E. J. Sun

The ADS system was developed to reduce accidents related to haul trucks operating under low visibility conditions in surface mining and construction sites, which is based on the GPS, mesh-wireless networks, and the Google-Earth 3D graphic engine as the graphic interface and mine-mapping server. This system has the capability to pin-point and track vehicles in real time using a 3D interface, which is based on user-based AutoCAD mine maps using the Google-Earth graphics interface. All equipped vehicles are shown in a 3D mine map stored in a local server through a wireless network. When low visibility conditions are present, the system indicates available exit/escape routes for driver safety. The research results indicate that the ADS system potentially increases reliability and reduces uncertainty in open pit mining operations by customizing the local 3D digital mining map, constructing the truck 3D models, tracking vehicles in real time using a 3D interface and indicating available escape routes for driver safety.

Oct 1, 2009

By Bernard Jones

LTUG ? A meeting of many mining companies that are using large tires ? Introduction of the mines and size ? Companies go over their usage of tires and performance ? As a group we discuss how the manufactures are doing with supplies and performance (who's running what sizes and manufactures they are using) ? The mine's best practices they use (which ones work for them and which ones don't) ? Where the mines see themselves going in the future ? What type of tire management the mines have in place

May 1, 2009

By G. A. Kosick, G. S. Dobby

"This paper presents the principles and application of a recently developed control system for flotation columns and column circuits. The control system uses triple pressure sensors to directly sense zone densities and level, and to help in characterizing the operating behaviour of individual columns. A complete expert system development tool is incorporated within the system to provide the facility for full operator training, an on-line help facility, and a means for incorporating the column behavioural patterns into decision making rules. The system is configurable to any number of columns and can be run in either supervisory mode or direct control through Minnovex PIO software. Additional process signals can be interfaced with the system if desired. Operating experience with the control system on the Minnovex column flotation pilot plant is described.I: INTRODUCTIONColumn flotation cells have been more difficult to control and are more sensitive to circuit changes than conventional mechanical flotation cells. This susceptibility encouraged investigation into various types of control strategies ranging from inexpensive single pressure measurements for level control, to highly instrumented and expensive systems using a variety of control methods.Flotation operators, in many cases, do not understand the column control philosophy or have not been trained to deal with this new type of cell. Some operators have subsequently absolved themselves of the column operating responsibility. Some column cells, for example, have run for hours with slurry pouring over the top or no froth coming off at all.ColumnEX is a column flotation control system which was developed from the viewpoint of an operating shift foreman who wishes to:1. control the column or column circuit through a genuine understanding of what is happening inside the columns, and2. to share this knowledge with his flotation operators and be available to guide them through times of circuit upsets."

Jan 1, 1990

By Zhuofei Yang, Jidong Kang, David S. Wilkinson

The fatigue behavior of AM60 high pressure die casting magnesium alloys was studied in a straincontrolled manner. The fatigue test was interrupted every 2,000 cycles for X-ray tomography scanning. The specimen was removed to be scanned on a desktop micro-CT system. The value of using X-ray tomography in a fatigue properties study was assessed with respect to porosity, cracks and fracture surfaces. The 3D analysis and model results showed porosity could be well measured and modelled in 3D. Defects bands are made of pores under 50 µm in volume-equivalent sphere diameter. Larger pores are randomly distributed in the region between two defect bands. Observation of cracks by X-ray tomography occurs in three ways such that the 3D model gives the best illustration of crack-porosity interaction while the other two methods have better detectability on crack initiation and crack tip observation. X-ray tomography is also of value in failure analysis on fracture surfaces. By summarizing X-ray tomography data during fatigue testing and observing fracture surfaces on a 3D model, a better understanding on the crack initiation, crack-porosity interaction and the morphology of fracture surface is achieved.

Jan 1, 2014

By Dave Rose, Jacques McMullen

"The Detour Lake mine is located 200 km northeast of Timmins, Ontario, Canada.The mill processes a free milling gold ore using both a gravity circuit and leaching with a state-of-the-art carbon-in-pulp circuit. The grinding circuit is a conventional SABC circuit with a tonnage of 55,000 tpd at 95 microns with the addition of pre-crushing upstream of the SAG mill.The Detour Lake mine has one of the largest gyratory crusher in the world (60"" x 113"") and over the years, many improvements have been made to this crusher with the result of improving plant throughput. This paper will present how choke feeding the gyratory crusher has been found to be one of the main influences on crusher product particle size and plant throughput. It will explain how the effect of choke feeding the gyratory was measured and from that, the various changes made to improve choke feeding of the gyratory crusher.IntroductionOre is hauled from the open pit mine and dumped directly into a single 60"" x 113"" primary gyratory crusher. The live capacity of both the feed and discharge hoppers of the gyratory crusher are designed for two (2) truck loads each, assuming a nominal payload of 300 tonnes per truck. The surge bin under the primary crusher feeds an apron feeder that controls the ore feed rate at approximately 4,200 tph onto a 227 metres long x 1.52 metres wide belt conveyor with a nominal capacity of 4,200 tph.The primary crusher is operated at an open side setting of 172 millimetres to produce a F80 feed to the secondary crushing circuit of 135 millimetres."

Jan 1, 2017

By D. M. Wyslouzil

"This paper was prepared for presentation at the 16th Canadian Mineral Processor's Annual Meeting, Ottawa, Ontario, Jan. 17 to Jan. 19, 1984.This paper gives an account of the development of treatment procedures for the differential flotation of refractory copper-zinc ores. Special references are made to the effectiveness of various zinc depressants and their combinations.Studies carried out on refractory copper-zinc ores demonstrated that conventional zinc depressants such as cyanide and zinc sulphate were not particularly effective when secondary copper minerals were present in the ore; the flotation activity of sphalerite was enhanced in the presence of cyanide.Among the various zinc depressants evaluated, the following depressant combinations were found most effective: Zn(OH) 2-S02 , 802-CaO, Na2S-Na2S03-S02, Na 2 S-S02 and Na 2S-S0rDS22.The practical application of any of these systems depends on the type of ore treated and other conditions such as pH, levels and points of collector and depressant additions.In this paper the effect of each depressant combination on different ores is described with reference to the selection of collectors."

Jan 1, 1984

By D. Brand

"The risk management objective of the AMIRA Code of Practice for Metal Accounting has seldom been systematically investigated in the literature up to the authors’ knowledge. Risk is defined in the Australian Standard on Risk Management (AS/NZS 4360:2004), as “the chance of something happening that will have an impact on objectives”. The simplified economic analysis performed in this paper has lead to define “something happening” as measurement non-representativity and “impact on objectives” as NSR loss from the optimal NSR. This has pinpointed a missing link being the establishment of a relation between NSR in flotation plants and measurement representativity. The proposed framework, referred to as the total cost of representativity, answers the previously unanswered question of how much accuracy/reproducibility is fit for purpose in a given flotation plant. Authors readily acknowledge that it is way easier to assess the cost of accuracy/reproducibility than the cost of inaccuracy/irreproducibility. However, this exercise not only answers previously unanswered questions but also establishes an essential link with operational excellence. This paper exposes why such operational excellence could neither be attained nor proved without a state of the art metal accounting system. This should impact not only how metal accounting systems are audited/designed/refactored, but also how flotation plants are designed.IntroductionBecause representative metal accounting is a vital source of information for the financial accounts of a mining/metallurgical company, the need for a code on metal accounting was recognized in 2001 and a team was formed in 2003, under the sponsorship of several major mining houses, to produce such a code. Table 1 exposes the two main objectives of this AMIRA Code of Practice for Metal Accounting."

Jan 1, 2017

By Paykan Safe

?? Background ?? WorleyParsons Gas Cleaning ?? PT Inco Smelter ?? Process Design Considerations ?? Furnace Control and Combustion ?? Combustion Chamber ?? Spray Chamber ?? Draft Control ?? Baghouse ?? Secondary Ventilation ?? ID Fan ?? Dust Handling Equipment ?? Project Execution ?? Heat Recovery ?? Conclusion ?? WorleyParsons Gas Cleaning ? Irving, TX ?? Formerly Gas Cleaning Technologies ?? Acquired by WorleyParsons in 2005 and now part of a global EPCM company ?? 14 years experience in off-gas system design for ferrous and non-ferrous facilities worldwide

May 1, 2008

By D. Rahal, I. Shah, B. Hines, S. Reddick

"The development of stirred milling technology has proven to be an enabling technology in fine grained metallic deposits. The increased grinding efficiency allows for the economic size reduction required to produce saleable concentrates. This improvement has opened the door to retreatment projects such as reprocessing of historic gold mine tailings. Recently a VXP2500 stirred mill was installed at Casmyn Mining Zimbabwe Turk mine to allow the reprocessing of historic mine tailings. After commissioning, an extensive joint research project between Casmyn and FLSmidth Minerals was conducted to optimize the performance of the mill. This paper outlines the challenges encountered in the optimization program and the outcomes from the joint research project.INTRODUCTION The development of stirred mills has opened up many new opportunities to recover valuable minerals from refractory ores. Stirred mills have already been reported as an enabling technology for the processing of fine grained ores in lead/zinc applications (Pease, Young and Curry, 2005). Historically, conventional ball mills were unable to economically grind material fine enough to produce the required recovery or concentrate grade. This often resulted in the loss of valuable materials to the final plant tailings. The advent of stirred milling has now provided an opportunity which has both economic and environmental benefits, the reprocessing of historic mine tailings. Many tailings stockpiles now contain economic concentrations of gold because of the ability of stirred mills to efficiently and economically grind the tailings to liberation sizes. The primary advantage of reprocessing historic tailings is very low cost processing. Recovering the tailings is usually as simple as pumping the material into the reprocessing circuit. The disadvantage of reprocessing tailings is the low feed grade and greater difficulty in recovery valuable minerals at the same size distribution. The material has already been previously processed so fresh surface area or an increase in metal exposure is required. These are both provided by regrinding the tailings material."

Jan 1, 2014

Peñasquito is Mexico's largest gold producer, consisting of two open pits - Peñasco and Chile Colorado - containing gold, silver, lead and zinc. Over the next three years, mining activities in the pit are expected to be focused on lower grade ore in the upper parts of the Peñasco pit while stripping is emphasized to ensure an economically optimal pit shell design to maximize the net asset value of the operation. By 2019, Peñasquito’s gold production is expected to benefit from an improvement in mined grades as it recommences mining higher grades at the bottom of the Peñasco pit and significantly enhanced metallurgical recoveries with the planned completion of the Pyrite Leach Project ("PLP").

Jan 1, 2017

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