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By D. R. Rice

"The Smoky Valley Common Operation is managed and 50 percent owned by Echo Bay Mine' s Round Mountain Gold Corporation. The other partners with 25 percent each are Homestake Mining Company and Case Pomeroy. The operation in central Nevada includes an open pit, 3-stage open-circuit crushing train and heap leaching on asphalt pads. Presently, about 18,000 tons per day of 0.039 troy ounce gold per ton are transferred to the leach pads, and a similar tonnage of leach residue is transferred to a waste dump. One million tons of ore are being leached at any one time.Gold and silver cyanide are adsorbed from pregnant leach solution on activated coconut shell carbon granules. Pressure stripping desorbs values from loaded carbon to electrowinning solution.Three electrowinning cells are operated in parallel. Each contains six cathodes. Each cathode includes about 40 troy ounces (2.7 pounds) of Number 2 medium coarse steel wool. The wetted area of each cathode is about 24 by 30 inches. Solution flow is 2 to 3 gallons per minute per electrowinning cell. Average current flow is 25 amperes per cathode. The voltage is controlled in the range of 3 to 4 volts to maintain desired amperage.Twice a week two cathodes are pulled from each cell and drained. Each cathode is split into four portions. These are put in a steel pan coated with WD-40 and dried overnight.Each dried cathode portion is put into a paper sack. Each group of four sacks corresponding to a cathode is weighed together. The typical weight ratio of loaded cathode wool to new cathodes is 9 or 10 to 1. To each sack is added 35 troy ounces of silica, 45 troy ounces of anhydrous borax, 35 troy ounces of nitre, and 5 troy ounces of fluorspar. The sacks are taped shut."

Jan 1, 1986

Agenda ? Introduction ? Inmet?s Operations and Closed Properties ? Inmet?s SECA Philosophy ? Inmet?s SECA Framework ? The Business Case for TSM ? Inmet?s TSM Reporting ? Inmet?s 2004 TSM Performance ? Opportunities for Improvement ? What Have We Learned From The TSM Process So Far? ? Summary Introduction ? Inmet has evolved into a strong TSM supporter ? Inmet is confident that TSM can be successfully and cost effectively implemented by smaller companies ? Inmet?s reporting on economic, environmental and social performance was raised significantly in our 2003 Annual Report ? a signal our commitment to good performance and improvement in these areas ? Our 2004 Annual Report has been further enhanced with the inclusion of our TSM performance

Apr 1, 2005

By Francisca San Martin, Tomas Vargas, Willy Kracht

"In Cu-Mo deposits it is usual to find considerable amounts of pyrite (FeS2). When processing this kind of ore by flotation, pyrite is rejected using lime to increase the pH to alkaline conditions (pH ~10.5). In the case of using seawater without pre-processing, i.e., raw seawater, the lime consumption increases dramatically and the recovery of molybdenite drops due to the precipitation of magnesium hydroxide on its surface. In order to avoid these negative effects, alternative ways of depressing pyrite should be considered.The current work introduces the use of Acidithiobacillus ferrooxidans, bacteria commonly used in bioleaching, as an alternative to depress pyrite in seawater flotation. The paper presents the results of biodepression in three systems: fresh water, water with added sodium chloride at 35 g/L (which corresponds to the salt concentration in seawater ) and seawater. The results show that it is possible to bio-depress pyrite with A. ferrooxidans in natural seawater pH (7.8-8.2). A similar behaviour is observed when running the experiments in fresh water, and in water with sodium chloride added.INTRODUCTIONWater is a scarce but essential resource for human development. The main reason for this scarcity is that, although 70% of the earth's surface is covered with water, only 3% of the total is fresh water and an important part of this water is frozen, so that only 1% of fresh surface water can be used for human activities. In Chile, most of the mining activity is concentrated in the north of the country, located in the Atacama Desert, considered the world's driest desert. That is why some mining companies have chosen to use seawater in their processes. For example, Esperanza (Antofagasta Minerals), and Sierra Gorda (KGHM International) use raw seawater in their flotation processes."

Jan 1, 2016

By K. Maruyama, T. Nagasaka, R. d. Chairaksa-Fujimoto, T. Miki

Electric arc furnace dust or EAF dust is considered as a hazardous waste but contains a significant amount of economically attractive non-ferrous metals especially zinc as zinc ferrite (ZnFe2O4) and zincite (ZnO). The hydrometallurgical process is one alternative choice because it has the advantage of low energy consumption. The leaching of ZnO from the dust is very easy. However, the complex major zinc compound in EAF dust is ZnFe2O4, which is very stable and insoluble in alkaline or acidic media under delicate conditions, and causes the low zinc recovery yield by hydrometallurgical process. Moreover, halogens and heavy metals in the dust are also problematic. In order to develop a new effective EAF dust treatment process, the authors have proposed "CaO addition process" as pre-dust treatment to transform all of ZnFe2O4 in the EAF dust to ZnO and Ca2Fe2O5. In this study, the selective zinc leaching from the CaO treated EAF dust with NaOH and NH4Cl solutions was carried out. The effect of temperature, reaction time and solute concentration were systematically investigated. All of zinc in CaO treated EAF dust was successfully leached into both solutions.

Jan 1, 2014

By T. Feldmann, G. P. Demopoulos

The feasibility of chloride leaching processes depends on interfacing them with cost-effective HCl regeneration technologies. This paper summarizes the most important findings of research conducted in the past 3 years concerned with a novel process to regenerate high-strength HCl from concentrated CaCl2 solutions at temperatures below 100°C, via reaction of CaCl2 with H2SO4 resulting in the formation of calcium sulfate phases (gypsum, a-hemihydrate or anhydrite). From constant supersaturation semi-batch experiments in pure solution it was found that the crystal growth rate of hemihydrate, and hence the particle size, was influenced by the rate of reagent (Ca2+, SO4 2-) supply to the reactor. Additionally, growth studies of DH in presence of impurities (K+, Mg2+, Sr2+, Ba2+, Fe2+/3+, Al3+, La3+, Y3+, F- and PO4 3-) showed that specifically Sr2+ and PO4 3- are taken up during crystal growth. Furthermore, it was found that decreasing water activity (via different HCl/CaCl2 concentrations) and increasing temperature reduce the metastable life-time of DH and HH by increasing the phase transformation speed. The DH/HH transformation was identified to be dissolution-precipitation based, while HH to AH is a topochemical process. Finally, continuous experiments on bench scale are underway to confirm the feasibility of the process to obtain super-azeotropic strength HCl with up to 9 mol/L (~30wt.%) from 5 mol/L CaCl2 (~40wt.%) solution.

Jan 1, 2014

By G. E. Veins

This paper summarizes an investigation in which beneficiated ilmenite ore was smelted in a continuous, three-phase, 250 kv.a., open-top electric furnace. Minus %. inch ore was smelted, using the standard method. Fine ore, in the order of minus 14 mesh, was smelted in the briquetted form by the open bath method, and in the unagglomerated form by the cold dry-top method. The latter was shown to be superior. The data obtained .are discussed at some length. During the investigation, slag aver-aging 82.5 per cent Ti02 was produced over a period of 87 hours, the maximum being 85 per cent. Such slag should .be particularly attractive for the production of titanium tetrachloride, from which titaniurn metal is produced. The advantages of using paper-mill bark for producing a furnace charge of low bulk density, as required in cold dry-top smelting, were emphasized.

Jan 1, 1957

By G. M. Castillo

Newmont?s Phoenix mine started production in March of 2006. Due to the extreme hardness of the ore, the mill has struggled to meet throughput projections. Grinding studies showed that optimizing the existing circuit would not achieve budgeted throughput. These studies also showed that the pebble crusher was being underutilized due to the inability of the SAG mill to break the rock. The concept was developed to supplement the feed to the existing pebble crusher with a secondary crusher. Models of this process looked favorable so a portable crusher was installed to test the process. The temporary crusher was successful at increasing the throughput by 7% and based on the operating data, plans are currently being developed to install a permanent secondary crushing system in front of the SAG mill. This paper will review the results from the test crusher and the flow sheet for the permanent secondary crusher.

Jan 1, 2012

By W. H. Patterson

The history and experience of early companies in the Islands is illustrated by the typical transactions of Trans-Western from 1959 to date. Trans-Western had entered into farmout agreements with companies strong enough to carry out at least the required minimum exploratory work and then such development as might be warranted. The farmee companies were required to make deposits to guarantee work performance during the first period of validity, i.e. the first 3 years of the 12-year life of the permits, and at the rate of 5 cents per acre. At that time, a good deal of geology was available, as a result of extensive exploration that had been carried on by the Geological Survey of Canada and other geological enterprises, with field parties travelling over and camping on all of those Islands. Trans-Western's farmees then selected, from Trans-Western's priority on 13.5 million acres, what they believed were the lands most prospective of producing large oil and gas discoveries, and, having the right to trim off acreage which they considered less prospective, thereby reducing the acreage of Trans-Western and its farmees to in excess of 5.5 million acres. The farmees then commenced a 3-year program carrying out geological exploration to the required minimum of 5 cents per acre, and with some permanent and many mobile camps.

Jan 1, 1969

By Michael Boyle, John Zeni

"The Blind shaft boring method is a mechanised process of excavating large diameter vertical shafts downward from the surface. It is a rotary drilling technique eliminating any requirement for personnel to enter the shaft or access underground workings during drilling and lining phases. Excavated material is delivered to surface carried by a flow of circulating fluid through the centre of drill rods. The drill assembly is suspended from a large A-frame rig and powerful winch at ground level providing vertical thrust to a hard rock cutter head. INTRODUCTION The Southern Coalfields Ventilation Shaft was constructed at a mine, 45 km north-west of Wollongong. The 5 m finished diameter (6.2 m drilled) shaft reaches a final drilled depth of 517 m, the deepest, fully lined blind bored vent shaft to date in Australia. Operated by a mining company in the Southern Coalfields, the expanding mine required a new ventilation shaft and associated surface infrastructure to service future operations. An assessment of future ventilation requirements for the coal seam operations identified a need to improve the capacity and reliability of the existing underground ventilation system in order to ensure a safe and efficient underground working environment. Installation of the new upcast ventilation shaft was determined to be the most cost effective and reliable solution to provide adequate ventilation for underground operations. The completed shaft is smooth and fully lined with steel/concrete composite liners that are hydrostatically sealed. The shaft lining is designed to meet the mine ventilation requirements for a service life of 20 years. The shaft intersects the top of the working section of the coal seam at approximately 513 m of depth. This includes the shaft collar depth and shaft bottom profiled intake section.PROJECT METHODOLOGY AND INDUSTRY BEST PRACTICE The shaft was drilled using the blind bore method, an innovative construction technique and an alternative to the traditional methods of sinking deep and large diameter shafts, such as raise boring and conventional drill and blast shaft sinking. The blind bore method allows the shaft to be drilled from the surface down without anyone having to enter the shaft or the mine during the construction process. This is by far the safest method of shaft construction and is especially suitable for difficult ground conditions where there may be unstable or water-charged strata. As this method involves drilling from the surface downward, shafts can be completed ahead of the underground mine development. Thus, allowing underground operations to focus on development and production without the conflicts of managing ventilation priority for underground contractors and mucking out spoil from excavation workings."

Jan 1, 2019

By J. F. Henderson

THIS paper relates to an area of more than 5,000 square miles in the Northwest Territories extending north from Great Slave lake and including-the Yellowknife, Beaulieu River and Gordon lake areas. Within the last three years much interest in the area has been created by the discovery of remarkably rich gold-bearing veins and the realization that thousands of square miles of unprospected ground are underlain by rocks like those in which the veins have been found. Probably there were more prospectors in this area in 1938 than in any other part of Canada. The area lies 650 miles north of Edmonton, and 425 miles north of the terminus of the Northern Alberta railway at Waterways, Alberta. The Athabaska and Slave rivers provide an excellent water route from Waterways to Great Slave lake for large oil and wood burning boats and barges which operate from the latter part of May to October. The only portage is around a 16-mile stretch of rapids on the Slave river between Fort Fitzgerald and Fort Smith. The town of Yellowknife, on the north side of Great Slave lake, has sprung into existence during the past year and is the centre for distribution of supplies for the Yellowknife-Beaulieu region. The Con-Rycon and Negus gold mines, which came into production in September, 1938, and February, 1939, respectively, lie about two miles south of the townsite. Excellent airplane service is available from Edmonton to Yellowknife and from Yellowknife to all parts of the area. The prospector and mining operator have come to rely almost entirely on the airplane for supplies and for the transportation of personnel, camp equipment, and canoes from Yellowknife to localities selected for intensive prospecting.

Jan 1, 1939

By R. W. Thompkins

"PREFACEThis paper will be published in three parts. Part 1, in this issue, will cover the occurrence of uranium, radiation from uranium ores, the uranium series, radioactive theory, radioactive equilibrium and application to the radon series, the working level, the theory of emanation and diffusion, transport by thermal diffusion of radon emanating from porous rocks, and definitions.Part 2, to appear in the October issue, will deal with radiation theory applied to uranium ores, other radon migration factors , fact ors affecting the radon gas release rate, measurement of radon gas emanation rates, the tunnel concept, variation of emanation rate with grade, and estimating radioactivity from grade analysis.The series will conclude with Part 3, in the November issue, which will discuss the techniques for controlling radiation and give some example calculations.1.0. Occurrence of Uranium1.0.1. Uranium is widely distributed in nature. Sedimentary rocks contain less than igneous or metamorphic rock s and as the outer 10 miles of the earth's crust is composed of 95 per cent igneous and 5 per cent sedimentary rock, it has been estimated that about 1.3 x 1014 tons of uranium exist in the earth's crust.1.0.2. It is not surprising, therefore, that radiation has existed naturally in the ear h ever since the beginning of time. It is found in such places as:(1) non-uranium mines;(2) houses not close to or connected to uranium mines;(3) ground-water tables supplying drinking water to large populations.1.0.3. All mines do not necessarily have abnormal radiation in them, but it is possible for many mines to have abnormal levels of radiation. Therefore, all underground mining operations should be tested for radiation."

Jan 1, 1982

Owner?s Team and EPCM ?Teams rolesmay vary to suit the skills available, however the tasksremain the same ?Ensure adequate level of capability in the team ?Large owner?s teams vssmall owner?s teams ?size of owner?s teams can reflect not only the individual level of capability but also the type ofrelationship with the EPCM contractor ?Wholly owned projects vsjoint ventures projects ?Both cases require clear accountabilities and authorities ?Project sponsor should be a senior executive with commercial andtechnical accountability of project outcome ?Project leader should be experienced and have solid leadership capabilities ?Attention should be paid to balancing personality types in an owner?s team

May 1, 2010

By T. R. Yu, D. B. Counter

"Kidd Creek Mines primarily employs sublevel blasthole stoping for underground mining operations. During pillar recovery in No.1 Mine and panel mining in No.2 Mine, the free standing fill exposures may reach a height of 100 m or more. Consequently, a competent consolidated rockfill has been required to fill the mined openings.Since 1976, a total of more than fifty stopes and pillars have been filled with over four million tonnes of backfill. Fill exposures, up to heights of 100 m, have stood up well after blasting adjacent to the backfill.The fill material consists of a graded aggregate, Portland cement and ground slag. Sand has been occasionally mixed in the fill material to serve as avoid filler. The aggregate is prepared in a fill crushing plant, transported underground through raises, and hauled to the filling stopes by conveyors in No. 1 Mine and by trucks in No.2 Mine.Two mixing methods are currently in use. No. I Mine utilizes the free fall of gravity; the fill materials are sprayed with cement slurry as the aggregate departs from the conveyor into a mixing culvert. The other is the use of a rotary mixer on a batch basis in No. 2 Mine.This paper describes the fill systems, filling operation s, and the backfill quality control practice, together with various testing results related to improving fill quality as well as reducing fill costs.IntroductionThe Kidd Creek minesite, located 27 km north o f the city centre of Timmins, Ontario, produces 4.5 million tonnes of copper, zinc, lead, and silver ores annually from its No. 1 and No.2 underground mining operations. Both mines employ a sublevel blasthole stoping method."

Jan 1, 1983

By G. A. Kosick, M. Freberg, L. A. Kuehn

"Highly variable and higher than forecast lead miff feed grades were problems experienced at the Polaris Concentrator. Limited flotation capacity and poor operating flexibility prevented the plant operators from overcoming these difficulties, and resulted in grades and recoveries which were lower than necessary.Two column cells were integrated into the lead circuit in an effort to give the operators the tools they required to achieve the best grades and recoveries possible, regardless of the miff feed grade. Installation of the column cells increased lead concentrate grade from 76% to 79.3% Pb, and increased lead recovery from 9/% to 91.3% Pb.This paper reviews the design, development and operation of column flotation cells in the lead circuit at the Polaris Mine.IntroductionThe Polaris Concentrator was constructed in 1980 on a barge in Trois Rivieres, Quebec, and towed to its pre sent location on Little Cornwallis Island, Northwest Territories, about 1450 km from the North Pole. The plant presently treat s about 2800 mtpd of new feed with average feed grades of 3010 Pb, 13% Zn and 5% Fe. Current production averages 36 000 tonnes of lead concentrate and 220 000 tonnes of zinc concentrate annually.The barge design and min e location dictated that the concentrator .be compact with very little unused floor space. As a result, flexibility was limited in terms of expanding the plant.Mill feed grades were highly variable and above forecast and the lead flotation circuit was found to be under capacity. This caused continued overloads in the lead cleaning circuit, resulting in low concentrate grades and recoveries. It was evident that an increase in lead flotation capacity and flexibility was necessary. The existing floor space did not allow for the installation of additional conventional flotation cells, but one alternative was the installation of column cells."

Jan 1, 1988

By R. Esteban, D. Runnels, J. Torrealba-Vargas, G. Couture

"Data handling is an important step in the development of a simulator of a mineral processing circuit. The model requires representative data of the scenario to be modeled. The model development involves protocols that must be followed very closely to complete a successful project.Data handling of large and diverse datasets (metallurgical test results, geological data, mining models, historical data, etc.) is a key element of the model. The information needs to be processed, reconciled, interpreted, modeled and presented to support the design or the optimization of a mineral processing plant.Best practice recommends that teams from different disciplines (such as mining, metallurgy, geology and environmental) interact to define the most important variables that could influence the simulator. For example by adopting a geometallurgical approach in the earlier stages of the project, it is possible to consolidate the number of main ore rock types in a testwork program (saving money and time) by involving geologists and metallurgists in the sample selection and data interpretation.Planning the development of a model involves an understanding of the software capabilities but also the limitations and the magnitude of the data required to calibrate the model in case of changes in the project.A successful model requires a deep understanding of the circuit to be modeled and thus plant personnel should be considered as members of the team.This paper describes the use of the "state of the art" tools for data analysis, simulation and optimization; and shows three practical examples of the use those tools in the design of mineral processing plants."

Jan 1, 2015

By Sejong Kim, Younghoon Moon, Youngseon Lee, Eunyoo Yoon, Yonghyun Song

"Mg alloy has a high specific strength, however, their thickness reduction was limited on most parts because of their poor stiffness. Since the modulus of rigidity is an intrinsic property, improvement of modulus of rigidity to the enhancement of stiffness is impossible. Therefore, the modification of shape and structure is available method to enhance the stiffness of real part fabricated by Mg alloy sheet. There are many thin walled parts which are located in outer section of electromagnetic system.Poor stiffness is often shown on wide surface area part with steel sheet, which has also high modulus of rigidity. In these cases, various groove patterns are used to increase the stiffness of part. However, some different methods have to be used when general groove pattern can’t be used. So, we would like to propose some new method to high stiffness on thin walled precision forging of Al or Mg alloys.An effect of proposed method on stiffness enhancement can be confirmed by fabrication of prototypes as well as structure and forming analysis based on FEM."

Jan 1, 2015

By Tony Szwilski

Using Unity 3D as a collaborative multi-user virtual on-line environment, an interactive virtual underground mine platform (IVUMP) is being developed to provide on-line access to mine safety preparedness training with a focus on mine emergency response exercises (MEREs). Communication and information flow among MERE participants and their actions can be monitored, recorded and evaluated. A mine ventilation simulation utility VFIRE is being incorporated to enhance the realism and interactive nature of the ?in-world? exercises as well as extend its functionality to include training in real-time ventilation and fire control.

Aug 1, 2013

Operationalizing the Ruggie Framework in a Mining Context Ruggie?s 3 Pillars: The State?s duty to Protect Policies, regulation, adjudication The Corporation?s responsibility to respect Acting with due diligence to avoid infringing Addressing adverse impacts when involved in abuses Access to Remedy ??even the most concerted efforts cannot prevent all abuse.?

May 1, 2013

By K. Lillkung, J. Kourunen, M. Latva-Kokko

"Carbon-in-leach (CIL) and carbon-in-pulp (CIP) processes utilize activated carbon to adsorb solubilized gold for recovery. Due to carbon attrition and non-ideal carbon management, however, some of the gold is lost in carbon fines and to the solution. The carbon attrition mechanism inside CIL/CIP reactors is mainly abrasion-related. This is critical to gold loss since gold loading takes place predominantly in the outer shell of the carbon particles. Thus fine carbon dust has a relatively high gold content and such a small particle size that it cannot be captured with safety screens. The attrition rate depends on ore and carbon characteristics, but it is always proportional to the mixing power intensity. This rate can be minimized by continuous suspension level measurement and control of agitation speed. In addition, a novel tank bottom structure can significantly reduce the required mixing power input compared to a flat bottom tank. A major challenge in carbon management is infrequent and inaccurate measurement of carbon concentration in the reactors. In order to reduce soluble gold losses by means of improved carbon management, Outotec has been developing a continuous in-situ measurement for carbon concentration that is tolerant to changes in slurry density.INTRODUCTION Cyanide leaching has been utilized since the late 19th century as a standard technology for hydrometallurgical gold production. Since then, gold and silver recovery rates have increased due to technological development, but very similar recovery methods are still being used. The original recovery method was to use zinc precipitation – similar to the Merrill-Crowe process, which is still common for feed materials with low throughput and high silver content. However, in most cases, activated carbon recovery is preferred due to its improved efficiency. The carbon-in-pulp process (CIP) and its modification, carbon-in-leach (CIL), have a lower residual soluble gold level and are not similarly affected by soluble base metals. The main alternative for the use of carbon is ion exchange resins. The principle of resin processes is similar to the CIL/CIP processes, with a different type of adsorbent material. Carbon processes are usually preferred over resin processes due to the significantly higher cost of resin material and the possibility to use simpler, well-established technology with carbon processes."

Jan 1, 2017

By M. Tardif, F. L. -Lavoie, M. Ruel

"In mineral processing, it is often very difficult to reliably measure several key operation variables. The harsh environment and high temperature encountered in pyrometallurgy processes lead to some difficulties when selecting the instruments, valves and actuators. If an important variable cannot be measured or manipulated adequately, controlling it can really become a big challenge. Sometimes, it is simply impossible to find the perfect equipment for the task. To help overcome these difficulties, a different approach is required. This approach will not correct the inherent problems related to the instruments and valves, but will cope with these problems. This article will demonstrate how modern process control techniques can be used to solve complex problems while remaining easy to implement. In this article we will described how soft sensors and multivariable fuzzy logic control were implemented at Koniambo Nickel to stabilize the furnace feed and allow for safe and reliable operation of an 80 MW DC arc furnace.INTRODUCTION Process Overview The process plant at Koniambo Nickel SAS is located in the North Province of New Caledonia, 310 km north of Noumea. The nickel-bearing ore is mined in the nearby Koniambo massif. After being screened and crushed, the ore is transported to the processing plant using a 12 km conveyor. After stacking in two blending piles, the ore, containing 2.3% nickel, is fed to the processing plant where it will go through the NST process (Nickel Smelting Technology) before being sent to refining and shotting. This article will focus on the improvement to control of the NST processes. The first steps of this process consist of milling the ore and removing all moisture through calcining (Figure 1)."

Jan 1, 2017