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By Ish Grewal

The ACACIA Reactor - Introduction What is it? The Acacia Reactor is a fluidized bed high intensity cyanide leaching system. Purpose for its existence? The Acacia Reactor was developed to treat high grade gold concentrates generated from primary gravity concentration systems. Why intensively cyanide leach a gravity concentrate? Current secondary upgrading processes, such as tabling, create significant losses of fine gold that is initially recovered in the primary gravity concentration units. Additional benefits include improved security and a reduction in health hazards associated with calcining.

May 1, 2002

By Ralph Harris, Xia Qi, Frank Komsic

"Gold cyanidation kinetics which are often limited in commercial operations by the rate of oxygen dissolution from gas bubbles into the slurry, are discussed. Emerging technologies for improving the rate of oxygen dissolution are compared and the gas efficiency, energy use and operating performance of inverted cones and a device based on a jet diffuser are examined. The effect of solids loading is also reviewed and a relationship between operating parameters and the kilograms oxygen dissolved per kilowatt-hour is presented.Inverted cones are shown to create slurry settling problems at high gas flow rates and surface tension lowering agents are shown not to greatly improve the overall rates of oxygen dissolution.The novel jet diffuser technology operates at a range of gas to liquid ratios that improves its energy use over conventional technology and the performance of a number of designs are discussed.Gas efficiencies as high as 35% were observed with the novel diffusers at 40 cm diffuser immersion and are expected to increase at greater immersions. Energy use of 1.8 kg 02 I kWh were estimated for prototype full size diffusers operating at 100 cm immersion. Energy use of 3.S kg 02 /kWh is conservatively expected at 600 cm immersion.IntroductionGold ExtractionGold that can not be recovered by gravity separation can be recovered by either the Merrill-Crow process or the newer carbon in pulp (CIP) or carbon in leach (CIL) processes 1. Reductions in operating costs and improvements in gold recovery are central mill operating strategies. The present paper examines the potential for improvement that can be achieved in the gold cyanidation step of gold recovery. This paper introduces a number of emerging technologies and provides a basis for comparison of the performance. It shows that the basis for comparison of a particular technology depends on the type of gold extraction circuit employed and the type of reactants employed."

Jan 1, 1996

By Michael W. Russnak

Productivity and operating expenses are everything when it comes to judging how well your mine and company are doing. Stakeholders are always looking at these numbers and trying to understand if productivity is improving, if operating costs are trending downward and what you are basing your decisions on. o make improvements you first need to understand how you are performing. If you can?t get this basic information, you will never improve. You will not be able to make simple decisions related to maintenance, operations or production. Forget about planning, as you will only be guessing based on the numbers some stakeholder or your executive wants to see. The problem miners run into is not that the data doesn?t exist; it does, but typically it?s raw, it?s everywhere and its volume is huge. Today there is more on-board computing capability in shovels than we had on our desktops three years ago. Add other mobile equipment, plant systems and multiple OEM vendors to the equation and the challenge is daunting.

May 1, 2007

By Stephen L. Chryssoulis

"""Preg-robbing"" of gold by carbonaceous matter during the cyanidation of certain types of carbonaceous gold ores is well documented. Recent studies established that ""preg-robbing"" of gold is not limited to carbonaceous matter. Gold sorbed on the surface of pyrite grains was detected and quantified by TOF-LIMS (Time of Flight Laser Ionization Mass Spectrometry). Crystallites of pyrite from a number of ores from different geological environments have been shown to have gold on their surface apparently sorbed from the ore forming solutions. Surface gold accounts for significant fractions of the gold head assay. Preg-robbing of gold by pyrite from pregnant cyanide solutions was also documented, and accounts for significant losses to tailings. Preventative measures are discussed.1.0 IntroductionThe detection and subsequent quantification of gold sorbed on the surface of pyrite particulates came about during routine determinations of the deportment of gold employing the comprehensive mineralogical approach (Chryssoulis and Cabri, 1990). In some pyritic gold ores it was discovered that the sum of the various forms in which gold ""conventionally"" occurs, was short of the gold assay. The mineralogical procedure used involves the independent determination of each fraction of gold, in other words there is no form of gold which is calculated ""by difference"". The systematic shortfall after having added the forms of gold listed in Table 1 led to the inquiry for the 'missing' gold and its discovery on the surface of pyrite grains, such as crystal facets and fractured surfaces.Preg-robbing of gold by pyrite from pregnant solutions was first described by Lloyd. In his studies, preg-robbing was measured by changes in the solutions/solids gold assays. This paper describes the first application of a direct measurement method for surface gold on pyrite particles from untreated and processed samples, its impact on gold deportment and processing. The advantage of the direct measurement lies in the absence of interference from other forms of gold, leading to more accurate and precise determinations of this unconventional form of gold."

Jan 1, 1997

By V. Coffin, T. Cienski

"(Figure 1) Reagentized pulp enters into the column at about 1/4 of the distance from the top. Inside the column it meets with a downward flowing stream of water and with an upward flowing mass of air bubbles. Flotation takes place in this counter current system while at the same time fine gangue particles are washed off the froth before it reaches the overflow lip at the top of the column. The main operating features of the column flotation are as follows:a) No moving parts. Solids are kept in suspention not by an agitating action of a propeller but by settling down against the rising air bubbles.b) Wash water. Spray pipes are installed a few inches below the froth surface and deliver required volume of water. The purpose of this water is twofold:(i) it keeps in balance the flow of material through the column and(ii) it washes rising froth in the froth layer as well as removes unwanted fines attached to the bubbles at the lower flotation section. As a result the concentrate produced is of higher purity than in the conventional flotation. Column is characterized by very high up-grading. However, even temporary disruption of wash water supply results in a drastic drop of concentrate grate.c) Flow balance. (Figure 2) For the correct operation volume of the underflow (tail) is larger than that of the feed. The difference is made up by the wash water. This difference called bias is predetermined and ranges from some 4 to 15 USGPM depending on the size of the unit and process requirements."

Jan 1, 1981

By G. Naud, J. Robitaille, M. Buonvino, A. Veltmeyer, A. R. Laplante

"A B6 Falcon concentrator was tested on several systems: a synthetic magnetite-silica ore, a massive sulphide gold-copper ore, a fine gold-pyrite-silica flotation tail, and a high grade gold ore in a low sulphide gangue (cyclone overflow).The Falcon demonstrated its ability to achieve separation in all cases, but with varying degrees of success. For the magnetite-silica system, separation proceeds until the concentrate bed overloads, at a mass of 300 to 400 g of magnetite. Recovery increased with decreasing particle size, down to the 25-37 µm and in some cases even the -25 µm class. Bowl geometry (angle) and gangue size distribution were the most significant operating variables. Results with the massive sulphide ore were the poorest, with gold recoveries typically around 10 to 20% at very low upgrading ratios, 1: 1 to 5: I. Gold recovery from the fine flotation tail ranged from 30 to 70% at upgrading ratios of 5 to 15; actual plant application would require a continuous unit (Falcon C20). The high grade gold cyclone overflow yielded a wide range of gold recoveries, but a very consistent relationship between recovery and mass processed. A concentrate of 0.5% Au could be processed at a recovery of 50%.The paper also presents results of a C20 application to recover fine iron from a magnetic tail. The unit is capable of recovering approximately 70% of the fine liberated iron in a high density product, with modest upgrading below 105 µm, and virtually complete rejection of the + 300 µ m product."

Jan 1, 1993

By D. Ingram

"PRIMARY DUST COLLECTOR A. 42,000 CFM James Howden Fan Z-6 Size 3650 Fan Dia 40"" HP 75It was found that the fan was not large enough to remove the air that was displaced by the trucks dumping. So it was removed and an enclosure was installed to isolate the gyro from the rest of the building.B. FANSJames Howden Fans Model RPM 3500 Series 357 FW HP 10These fans were installed when the first dust system was put into operation. It was found that the high RPM and extreme fan wear caused a major maintenance problem. These fans were replaced with Chicage Blowers Model SWS1 RPM 1180 Dia 36"".DRY CYCLONE COLLECTORS A.,Three four foot rubber lined cyclones. Four six foot rubber lined cyclones.All under flow. Water is controlled manually and gravity flows to a central sump box. From there it flows to the grinding circuit in the Mill.Cyclone under flow product runs between 100 and 200 tons of dust per 24 hours with a screen analysis 30% + 400.The cyclone under flow product is diluted to about 3 to 4%. Solids total gallonage approximately 400.B.,Elbair Wet Scrubber125 HP RPM 56042,000 CFM,Model PX861The Elbair collects the total product from the discharge. Of the Cyclone fans the under flaw goes to the Mill - the Elbair discharges stack goes to atmosphere.The Elbair wet scrubber had to be redesigned in order to keep it in service."

Jan 1, 1976

By R. A. Bergman

"Process descriptions are provided for the following ten plants that treat high-magnesia lateritic nickel ores (saprolite) by pyrometallurgical means: PT Aneka Tambang; Cerro Matoso S.A.; Falconbridge Dominicana C. por A.; Hyuga Smelting Company Ltd.; Larco (Societé Minière & Métallurgique de Larymna); Loma de Niquel; Le Nickel, SLN-Eramet; Nippon Yakin Kogyo Company Ltd.; Pacific Metals Company Ltd.; and PT Inco Indonesia.Flowsheets, equipment information,chemistry and production data have been compiledfor plants based on both information providedby the companies and on calculated massand energy balances.IntroductionNickel is of vital importance to modern society. Without it, we would not be able to enjoy many of the things that we take for granted, such as computers, airplanes and stainless steel appliances in our homes and workplaces, to mention a few.Nickel occurs in nature both as sulphide and oxide ores. Approximately 36% of the nickel reserves in the Western World occur as sulphide and 64% as oxide ores. Sulphide ores respond to concentration processes, whereas, oxide ores do not. Sulphide ores mined at 1% nickel can be readily concentrated to 10% nickel, whereas, oxide ores cannot be concentrated and therefore have to be processed as mined.Laterite ores are normally classified intotwo groups:1. The high-magnesia ores, saprolites or serpentines, are, as a rule, processed by smelting. The main reason for this is that the nickel replaces magnesium in the magnesium-silicate lattice. To be able to recover nickel, the lattice has to be destroyed. This can be achieved by smelting under reducing conditions.Acid leaching is also possible, but in this case, large amounts of MgSO4 or MgCl2 will be produced making it costly to regenerate the acid.2. The high-iron, low-magnesia ores are known as limonite. The nickel is relatively loosely bonded to goethite and hence can be recovered by selective reduction followed by ammonium-ammonium carbonate leaching. In recently developed processes, these ores are also being extracted by acid pressure leaching, with high Ni and Co recoveries.This paper focusses on the production of ferronickel and nickel matte from the highmagnesia ores."

Jan 1, 2003

By Chris Brown

"The Island Copper plant was designed and built by Fluor Utah Ltd, in conjunction with Utah design staff, Originally designed to treat 33,000 tons/day (t/d) of ore, the current average milling capability is 38,000 t/d (Nov'74). The first of six semi-autogenous grinding lines was brought on line in October 1971, startup of the remainder being governed by equipment delivery schedules.The summer of 1973 saw the start-up of an additional three ball mills, and attainment of the present production level. The current process flowsheet is shown in simplified form.CRUSHINGThe crushing circuit is relatively simple, comprising single stage crushing of the ore followed by screening to fine and coarse fractions.The crusher is a 54 x 74in. Allis Chalmers Superior Gyratory with a setting of 9-lOin., driven by a 500-hp motor. Trucks dump on three sides of a rectangular dump pocket. An 84in. x 20ft. link belt apron feeder draws crushed ore from a 250-ton surge bin below the crusher, discharging onto a 72in. wide inclined steel cord conveyor belt. A fixed splitter box at the conveyor discharge separates feed to two parallel Jeffreys 6 x 20ft. vibrating grizzlies for screening into +4in. and -4in. fractions. The fractions are collected on short reversible conveyors which feed the coarse and fine ore stacker conveyors. Trippers distribute ore to outside stockpiles adjacent to, and above, the concentrator grinding 'floor."

Jan 1, 1975

OVERVIEW OF PRESENTATION ? What is LMI ? Who uses LMI and how? ? Value of LMI to the Mining Industry ? Mining Industry Workforce Information Network (MIWIN) ? The Challenge: Forecasting the future in uncertain times ? Results: Hiring requirements in the next decade ? Results: Occupational information ? Next steps

May 1, 2009

By J. A. L. Henderson

THE potential oil-and gas-bearing area with "which this paper deals is the large undefined Carboniferous basin, roughly triangular in shape, occupying about 10,000 square miles of southern and eastern New Brunswick. Its base, about 135 miles long, lies on the gulf of St. Lawrence and embraces the whole eastern coast-line of the Province, while its apex lies in the south-west corner of the Province, near the International boundary (see map, Figure 1). The Carboniferous basin may be divided roughly into two areas-the Northern basin and the Southern basin-by a structural feature represented by a ridge of low hills running north-easterly from the Saint John river, near Saint John, on the southwest, to Indian mountain, about eight miles north of Moncton, in the northeast. Within the Northern basin, all evidence regarding the presence or attitude of the older Mississippian Albert Shale series, the only oil-bearing rocks known in New Brunswick, is for the greater part obscured by a thick and practically horizontal blanket of Pennsylvanian strata and, although evidences of oil and gas have been reported, none has been positively identified. Five parallellines of gentle folding, running to the northeast, occur in the Pennsylvanian rocks, within a distance of 100 miles from north to south. This folding is reflected in the courses of the rivers, which lie within the synclines. The relationship of the folding in the younger rocks to structures in the uncomfortably underlying older rocks is unknown, but should now be possible of clarification by means of a geophysical survey accompanied by drilling. Independent geological examinations have yielded no evidence of value in this respect, nor have five exploratory boreholes drilled by per-cussion tools to a maximum depth of 3,645 feet been of assistance, as only one inconclusive hole completely traversed the beds which normally overlie the Albert shales.

Jan 1, 1940

By Dara L. Hrytzak-Lieffers

Canada has long since been a place that has led the world in mining development, in a safe, clean, and sustainable manner. This has led to the integration of corporate social responsibility (CSR) philosophy in corporate governance, policy, and programming. The paper will identify the basis of CSR practise in Canada?s mining industry and provide a Canadian example of CSR implementation. Biography Dara Hrytzak-Lieffers is the manager, corporate social responsibility at Cameco Corporation. She oversees corporate CSR initiatives including the Sustainable Development report and public engagement programs. Dara received her BA in International Studies from the University of Saskatchewan and an MA in International Conflict Analysis from the Brussels School of International Studies. She is a recent graduate of the World Nuclear University summer institute.

May 1, 2011

By A. J. Vivyurka

"This is a talk about the experiences that Rio Algom Mines Ltd. has had in the Elliot Lake uranium area trying to make the tailings more compatible with the surrounding environment. To get a better idea of the problem that we are associated with we have to go back to the location. The Elliot Lake uranium area is situated about half way between Sault Ste Marie and Sudbury and is about 20 miles north of Lake Huron. In 1950, uranium was discovered along the north shore of Lake Huron and by 1961 we had up to 9 mines operating in the area. Then the United States Atomic Energy Connnission withdrew their contracts so that at present there are only 2 mines operating. From all the mines that we had operating, we ended up with 7 tailings areas. From these 7 tailings areas we have 5 sites where we have active treatment or rehabilitation. There is the Pronto site where we are treating uranium tailings and copper tailings. There is the Lacnor-Nordic site which is located just out of Ellio Lake. The Milliken-Stanleigh site is in the Crotch Lake area. The Panel tailings is off the north end of Quirke Lake and finally there is the operating property of Rio Algom Mines at Quirke Lake.To understand fully the problem with this rehabilitation we have to look at the constituents of the ore. The ore body is a quartz conglomerate with uraninite and brannerite as the uranium bearing minerals in a fine ground mass of quartz, sericite and pyrite which separates the larger quartz pebbles. The approximate composition of the ore is: 80% quartz, 13% chlorite, 7% pyrite and 0.2% uranium minerals. The processing method also adds a few constituents to the final tailings."

Jan 1, 1975

By C. J. Preston, R. E. Ström, G. R. Baiden

"On January 1st 1996 Inco Limited, Tamrock OY, Dyno Explosives Group and CANMET formed a consortium for the development of robotic mining equipment. This project is a five year research and development agreement that combines the talents of the above organizations to facilitate the creation of mining equipment and systems for robotic mining.The projects are based on the communication system developed by Inco Mines Research and currently sold and marketed by Automated Mining Systems Limited. Main projects include the development and implementation of a positioning and navigation module (including a software mapping system that will be inherent to each piece of equipment), robotic systems for development and mining, and software systems to support the use of this equipment. Included in the program is the establishment of a test mine, at Inco’s 175 ore- body at Copper Cliff. This facility will allow collaboration of companies and research organizations for the design and testing of techniques and equipment for Robotic mining.This paper discusses the creation of this new research alliance, the Mining Automation Program or MAP."

Jan 1, 1997

By T. Salman

Most authorities agree that the dissolution of gold from an ore takes place according to the Elsner equation first stated in 1846. The main requirements for the dissolution reaction to proceed are:(1) that the gold be clean.(2) that the gold be exposed to the solution.(3) that the cyanide solution be active, i.e., not over loaded with impurities which could retard or inhibit the reaction.(4) that an adequate supply of oxygen be available (from air).When the above conditions are met, cyanidation becomes basically a mechanical operation.Minerals such as quartz, calcium carbonate are relatively inert to cyanide though they may give rise to mechanical troubles. Most ores present an assortment of chemical problems, depending upon the constituent present, which react to the solution to varying degrees. It should be borne in mind that minerals which are disturbing to the operation, though present in small amounts, usually exceed the weight of the gold by several hundred times. In addition, the application of flotation and other forms of concentration to gold ores, previous to cyanidation, concentrates not only the gold, but also the other heavy minerals and these complicate the chemistry of the process.

Jan 1, 1975

By C. Patel, George H. Hope

"INTRODUCTIONThe Hemlo area is located in Northern Ontario, some 350 km east of Thunder Bay along highway 17. Hemlo is Canada's largest, recent discovery of gold ore. Three companies, Lac, Noranda, and Teck are currently developing mines and processing facilities in the area. A combined milling capacity of approximately 10,000 tonnes per day will ultimately be available in the area. The gold yield will be between 750,000 to 1,000,000 ozs. per year. This will slightly more than double Ontario's gold production but only represents 2.5% of the total world gold production.Lac Minerals Ltd. is substantially committed to the gold mining business. Lac currently operates four (4) gold mines and mills and produces 300,000 ozs. per year. Lac's Hemlo development will put the company in the position of number one gold producer in Canada.The Lac Hemlo ore body has an estimated reserve of 37 million tonnes at 6.2 g/t. The mining will take place at an initial rate of 3,000 t/d commencing in the first quarter of 1986. The mine and plant will be expanded to 6,000 t/d in 1988. At this capacity, Lac will be the largest producer in the Hemlo area.1. GEOLOGYThe orebody is divided into two (2) zones for mining purposes. The 'A' Zone is to the east and dips to the Northeast from surface to 300 m below surface. This zone has a strike length of 250 m to 300 m at an average width of 20 m. The upperpart of the zone will be mined by open pit and the remainder from underground. The 'B' Zone, to the north west of the 'A' Zone, although lined up is not necessarily an extension of 'A' Zone. 'B' Zone has a known strike length of 600 m and is open to depth and along the strike. It is over 70 m wide in the core. This zone holds most of the property's known reserves. 'C' Zone with narrow gold zones is under exploration in the south west portion of the property."

Jan 1, 1985

By G. Winkel

"Safety conditions in industry have greatly improved over time. However, around the world, in Canada, and in each province or territory, people are still the victims of serious industrial accidents. The increasing safety of people at work then continues to be an imperative in industry today. In addition to protecting people, safety has been shown to make good business sense in any industry.The road to safety improvement is built on establishing a culture of safety that forms the basis for how work gets done in a company. Most importantly, an effective safety culture is built on the full engagement and participation of workers and leaders alike, who share in a vision for safe work performance where “no one gets hurt” and “everyone is a leader in safety.”Let’s learn together on how we can make a safety culture happen. The resulting bias for safety will ultimately save lives, and fulfills our moral objective to strive for safety excellence. IntroductionWe have the good fortune of living in democratic countries where freedom and the value of human life are key beliefs. These beliefs translate into the moral obligations and laws that we value and uphold in our society and life today.A minesite or workplace is simply a necessary part of our society where people earn a living. It is a place where our moral obligations and laws equally apply, a place where human life is of ultimate importance and value. In the early years of industry, this value has not always been evident. Take this description of a tragic accident reported in a coal mine on December 8, 1879:“Oliver Thompson, shaftman, aged 35— While taking wooden partitions out of a ventilation shaft, he fell off the work platform a distance of 100 yards, there did not appear to be anything unusual to account for this accident.”"

Jan 1, 2004

By C. Vanvoren

"Since 1975, the Aluminium Pechiney Research Centre at Saint-Jean-de-Maurienne (LRF) has been concentrating its efforts on designing, testing and perfecting the Aluminium Pechiney point-fed prebaked reduction cell.In 1979, the AP18 cell (180 kA) was industrially launched with the construction and start-up of the F line in Saint-Jean. The following generation, the AP30 (300 kA), with prototypes started in 1981, was launched in 1986 on the Saint-Jean G line. Along with cell design, efficient process control systems were developed to pilot alumina feeding and bath composition. Together, these pots are currently producing 4.6 Mt of aluminum, i.e., 18% of the world’s overall yearly production.In 1989, the research centre faced a new challenge: to push the limits for the size of a reduction cell to further improve the profitability of Greenfield projects. This new generation development was also the opportunity for a significant redesign of the Aluminium Pechiney electrolysis information system.With a track record of ten years of semiindustrial operation with three prototypes, the AP50 technology is now ready for industrial implementation and enables a significant breakthrough to be made in terms of return on investment of a Greenfield smelter."

Jan 1, 2002

By C. D. Shackelford, J. F. Muñoz, M. Vauclin, P. Rengifo, A. Suazo

The results of a field-scale study involving in situ leaching of copper ore tailings using sulphuric acid as the leaching agent, injection wells to introduce the leaching solution and extraction wells to recover the copper-enriched pregnant leaching solution are presented. The study was performed at an abandoned tailings disposal site using a battery of injection and extraction wells. The medium was characterized through the determinations of physical, chemical, mineralogical, and hydro-dispersive properties based on laboratory and field tests, including a tritium tracer test, a pumping test, particle size analyses, and hydraulic conductivity tests. Numerous horizontal strata with different hydraulic conductivities were identified. A previously developed model was used to simulate the leaching of copper ore tailings. Although the study confirms the feasibility of using in situ leaching for recovery of residual copper from tailings deposits, the efficiency of the technology depends significantly on the medium stratigraphy and hydraulic conductivity.

Jan 1, 2001

By André van Wageningen

Since the beginning of this century Boliden Mineral and Atlas Copco have worked together in stages on improving the accuracy and quality of drilling. Navigation of the drill rigs with IREDES has been in use in the Boliden mines for several years. Recently the capability of the system has extended with map navigation to more accurately follow the ore in cut&fill mines. The system allows for changes on the individual round level to follow the ore without changing the whole design for the heading. Those changes are done in a CAD-system and remove the need for face markings and will allow for even better accuracy in both height and wall position. All the information between the CAD-system and the drill rigs is exchanged using the IREDES standard. This paper describes the workflow and the use of the IREDES standard.

Oct 1, 2009