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By Jae-Chun Lee, Rajiv Ranjan Srivastava, Min-seuk Kim, Byung-Su Kim

Recycling of spent hydrotreating catalysts (HTC) can potentially contribute towards the sustainable extraction of metal values. Treating such materials by hydrometallurgical methods to separate metals from the leach liquor of either acid/alkali media is a major step. In the present study, separation of molybdenum from HCl leach liquor of spent NiMo type HTC has been investigated by applying solvent extraction using Cyanex-923. For this, the chloride solution containing 973 mg/L Mo, 254 mg/L Ni and 1634 mg/L Al was taken as the aqueous feed. The parameters including contact time, concentration of the extractant, acid and chloride, and phase ratio were varied to investigate their effect on the extraction efficiency. The McCabe-Thiele plot suggests that > 99% Mo-loading using a 2-stage extraction process. From the molybdenum depleted solution, nickel was selectively extracted by Cyanex-301 leaving Al in the raffinate.

Jan 1, 2014

By Andre du Preez

Emergency Fall Arrest System Rio Tinto?s Primary Objective: ?To achieve repeatable controlled safe deceleration rates during emergency fall arrest activation (Ontario OHSA Regulations) ?Must operate effectively on mine specified steel shaft guides.

May 1, 2013

By F. Habashi

Lead is an ancient metal, has been produced to-date from its ores exclusively by pyrometallurgical route. The process suffers from high operating cost and excessive pollution problems. Extensive research has been going on since the beginning of the twentieth century to find a non-polluting process for its production and a solution for its complex refining scheme. It has been assumed correctly that the hydrometallurgical route should be the most promising. Pilot plants have been constructed and operated for a reasonable periods, but no process has proved to be satisfactory. As a result, a number of smelters and refineries have been shut down. The present review analyses the situation and suggests that the best route to treat lead sulfide concentrates is by leaching with fluoroboric acid, HBF4, containing ferric fluoroborate, Fe(BF4)3, and electrolyzing the solution in a diaphragm cell - - a process recently invented by Italian metallurgists. In this process, any silver present in the concentrate remains in the residue together with elemental sulfur and can be recovered by known methods.

Jan 1, 2008

By M. H. Kotze, V. Yahorava

A gold-selective ion exchange resin, containing tributylamine groups, was developed by Mintek for the recovery of gold from cyanide leach solutions. The Dow Chemical Company and, more recently, Purolite commercialized the production of this gold selective resin for use in the gold mining industry, and it is marketed as Dow XZ-91419.00 and Purolite A194 respectively. A novel application of this resin is the selective recovery and separation of AuCl4 - f rom p latinum group metals (PGMs) in chloride and nitrate solutions. The current paper describes potential benefits of this type of resin for selective recovery and upgrading of gold from low grade chloride or nitrate waste streams, and the possibility of gold separation from PGMs during their refining in chloride media.

Jan 1, 2014

By Gustavo Brunello

Motor Failure Rates and Cost ? Motor failure rate is estimated: 3-5% per year. ? In Mining, Pulp and Paper industry failure rate is up to 12%. ? Sometimes process downtime costs are higher than motor ?? Motor failures are due: Electrical 32% Mechanical 31% Environmental 36%

Feb 1, 2008

By J. Buckle

"Recognition of the diamond potential of the Wawa subprovince was initially determined from regional data using a kimberlite model. The world’s largest stable Precambrian craton, the Superior Province, is considered to be favourable for the emplacement of diamondiferous kimberlite. The Wawa area is located near the intersection of intra-craton structures visible in the regional magnetic data.The Enigma project is located north of the town of Wawa in northern Ontario. From field evidence and background research, it became obvious that in the Wawa area there were at least two potentially diamond-hosting events, Archean lamprophyric volcaniclastics and Proterozoic kimberlites. The host lamprophyric rock does not contain the classical KIM signatures. However, to complicate the Enigma, stream sediment samples within 200 m of the diamond-bearing lamprophyre produced a typical suite of kimberlite indicator minerals.The micro- and macro-diamond content of the Wawa lamprophyric volcaniclastic rocks is typically 0.2 ct/t to 1 ct/t, although it can be higher locally. The economic diamond potential of these Archean dykes, sills and irregular lamprophyre bodies is still under-explored (Kaminsky, 2002, unpubl.). Oasis Diamond Exploration is currently exploring the area using geophysical, geochemical, and geological data."

Jan 1, 2002

By Z. I. Zaki

Synthesis of TiC /A1203 Composite from TiO2, Al and graphite using combustion technique has been investigated at different initial temperatures; room, 400 and 600 °C. The effect of initial temperature on the composition of the product, wave velocity and combustion temperature of the reaction was studied. The measured combustion temperature and wave velocity were increased with increasing the initial temperature of the combustion reaction. The maximum wave velocity obtained was 5.9mms-1 when conducting the combustion reaction at initial temperature of 600 °C. Oxidation resistance of the obtained composite was also studied at the temperature range 300-800 °C. No oxidation is detected before 400 °C while it takes place effectively at 700 °C forming different titanium oxides. Wave velocity measurements method was used to calculate the activation energy of the reaction between the starting materials. It was found to be 316.34 kJ mol 1 at the temperature range that was studied.

Jan 1, 2007

By N. Bédard

"This paper highlights Cambior’s initial approach for recruiting and retaining its international employees, the importance of proper preparation and the support needed to ensure a competent and stable workforce.In general, most of the training and information available for human resources personnel prepares the specialist for handling various aspects of labour relations, recruitment and hiring, benefits administration, employee relocation, etc. This is usually done in a Canadian context.Only recently, has more specialized training been developed to prepare human resources practitioners for the complex issues related to expatriate employees and dealing with human resources issues in other countries"

Jan 1, 2004

By K. L. Boyd

"Can the increasing tonnages of ore and waste mined today be accommodated simply by using bigger and better crushers? This paper reviews the latest primary crushing and large cone crusher designs. It highlights how—in addition to using the larger crushers now available—maximizing the utilization percentages in each stage of the rock size reduction circuit will assist in meeting the larger production requirements of existing and new mining operations. Its goal is to help consultants and operators select the optimal equipment and custom-designed items in material handling from the mine to the mill, maximizing operating hours per year.RÉSUMÉ Le recours à des concasseurs plus grands et plus performants suffit-il à gérer l’augmentation du tonnage du minerai et des déchets que l’on extrait de nos jours ? Cet article examine les tous derniers modèles de concassage primaire et de grands concasseurs à cône. Il montre que, pour satisfaire aux exigences de production plus conséquente des exploitations minières existantes et nouvelles, il est important d’optimiser les taux d’utilisation à chacune des étapes du circuit de réduction de la taille des roches, en plus d’utiliser les concasseurs plus grands actuellement disponibles. L’objectif de cet article est d’aider les sociétés d’experts-conseils et les exploitants à sélectionner le meilleur équipement ainsi que des articles fabriqués sur mesure pour la manutention de la mine au concentrateur, en optimisant les heures d’exploitation par année.INTRODUCTIONAre larger crushers the answer to meeting the demands of existing or new mining projects for increased tonnage? Boyd (2002) predicted that larger crushers for primary and fine crushing would be beneficial and contribute to the further development of mineral processing. Larger crushers for primary and fine crushing applications have since become available.The rock size reduction process from the mine to the selected milling process facility has not changed since a person first broke a rock to get at the interesting mineralization within. The rock size reduction process circuit from the mine to the mill can be summarized in four stages:• stage 1: mining (rock breakage and fragmentation);• stage 2: prescreening (scalping);• stage 3: primary crushing; and• stage 4: fine crushing (secondary, tertiary, and quaternary).Plant throughput and ore delivery schedule will form the basis for flowsheet design and equipment selection. Once the project design criteria and the mine plan have been established, the circuit’s utilization percentage (percentage of hours when the circuit is being utilized) can be optimized for each of the four stages. The mining and process departments play a key role in the selection of the final comminution circuit, and both departments should be familiar with and contribute to the design of the circuit."

Jan 1, 2017

By Linda Dufour

"Autoclaves have been in commercial use in the mining industry since the early 1950's the initial applications included tin, uranium, cobalt, nickel and copper extraction under both acidic and alkaline conditions. These circuits varied in batch or continuous operation. The geometry has been spherical, vertical, and horizontal type with up to six agitators, with throughput as high as 1000 stpd.Presently autoclaves are a good process selection for many refractory sulphide gold bearing ores. The first application of pressure oxidation in the gold industry was at the Homestake Mcglaughlin's Mine which was commissioned in 1985. This was an acidic pressure oxidation process treating 3000 stpd in three four compartment horizontal autoclaves 14' diameter and 53' long. Since the initiation of autoclaves for the treatment of gold bearing sulphides, there are presently 16 gold autoclaves operating worldwide varying in size up to 18'4"" inside diameter. There are seven autoclaves for the treatment of refractory sulphide gold bearing ores to be commissioned in 1997 and 1998.Autoclave technology has progressed extensively since the mid-eighties. Operational experience has made rapid progress and the result is much smoother and safer autoclave operation. There have been many advances in autoclave technology design. For example, the use of exotic materials for corrosion resistance to reduce down time for maintenance. The instrumentation involved in autoclave operation is very sophisticated which allows for many safety features. The advanced design has allowed for greater availability and as a result operating costs and maintenance costs have decreased. These technological advancements have made autoclave technology more safe and this has resulted in a greater acceptance of this type of operation. Many of the gold autoclave facilities operate up to 9 months continuously without shutdowns. The advancement of autoclave technology has inspired many new applications.Because of the outstanding operation of autoclaves in the gold industry, many other applications for autoclave technology are being considered. The following is a list of autoclave applications:"

Jan 1, 1997

By J. Currie, J. McManus, R. Chenier

"Cominco Copper Division's Valley Mine is located in the Highland Valley of British Columbia, approximately 275 km by air northeast of Vancouver. The nearest towns are Logan Lake, located IS km to the east and Ashcroft, located about 50 km to the northwest.Preproduction stripping of rock and overburden at the Valley Mine's Lake Zone Pit began in mid-1982 following a decision to discontinue mining in the adjacent Jersey Pit. Equipment and mining methods were carried over from the Bethlehem Copper operations which, with Valley Copper Mines, were merged into Cominco in December 1982.Blasting practices, as carried over from the Bethlehem pits, were designed to provide the fine fragmentation required to meet production requirements using the Bethlehem crusher. However, after mining the first few benches of the Lake Zone Pit, it became apparent that overblasting at the pit limits was causing a number of bench failures, as well as contributing to an over-all reduction of the material strength of the rock mass forming the southwest wall of the pit.With present ultimate pit plans calling for the southwest wall to be as high as 300 m, Valley staff realized that potential slope stability problems should be dealt with as early as possible. This philosophy would enable experimentation on phase pit walls in order to attain the optimum slope angle on the ultimate pit wall.As part of an over-a ll slope stability program, a controlled blasting program was initiated at the Lake Zone Pit in March 1983. In this program, Valley engineering and production staff worked together with Golder Associates in establishing design criteria and evaluating the results. This program resulted in a marked improvement in the soundness of pit walls while maintaining the required degree of fragmentation."

Jan 1, 1985

By Xiang-dong and Zhu, Xia-jie Hao, Yi-lin Fan, Quan Jiang, Lian-xing Hu, Xia-Ting Feng, Shao-jun Li

"Columnar jointed basalt (CJB), which typically originates from lava flows, is characterized by a special geological structure. The joint network inside the CJB is self-organized into a rough hexagonal arrangement. The field test and measurement during the unloading excavation showed that the columnar joint sets and other internal joint sets not only are important for determining the mechanical properties of the CJB, but also induced its asymmetric unloading deformation and failure. A constitutive model, which considered mechanical deterioration of both the joint sets and rock blocks, was also developed to simulate the unloading behaviour of the CJB. The crack-confinement supporting method for surrounding CJB was developed to overcome the failure of columnar jointed rock mass in the diversion tunnel. Application to the CJB segments of the diversion tunnels in the Baihetan project indicated that this supporting method was reasonable and efficient. INTRODUCTIONColumnar jointed basalt (CJB) rock mass, which typically originates from lava flow, is characterized by a special joint structure. The joint network of the CJB is self-organized into a roughly hexagonal arrangement and leaves behind an ordered colonnade. The widely accepted current view regarding the formation of columnar jointing involves a thermally induced contraction–cooling mechanism (Peck and Minakami, 1968; Degraff and Aydin, 1987; Budkewitsch and Robin, 1994; Lore et al., 2000; Goehring et al., 2006). Although the columnar basalt formation mechanism is fairly understood, the geotechnical characteristics of such rock mass are not well established. In practice, joint sets always induce the multi- failure modes of surrounding rock in the tunneling space (Ibarra et al., 1996; Waltham and Swift, 2004; Mahendra and Bhawani, 2008).According to conventional wisdom in rock mechanics, structural joints affect the mechanical response of rock mass by introducing strong anisotropic effects (Barton and Bandis, 1980; Hudson and Priest, 1983; Brady and Brown, 1985). The columnar jointed rock mass should be considered an anisotropic material given that the joint sets are distributed with some principal directions and characteristic spacing distributions (Cundall and Fairhurst, 1987; Hoek et al., 1998; Wu and Wang, 2001; Budetta and Nappi, 2011; Fortsakis et al.,2012). Columnar jointed rock mass would result in structurally controlled failure patterns, even serious disasters during underground excavation because of the low shear and tensile strengths of intensely joints (Gencer,1985 ;Ishida and Uchita, 2000; Jia and Tang, 2008). The CJB rock mass in the Baihetan hydropower station has exhibited serious stability issues, including sliding, fracturing and even collapse (Shi et al.,2008). Therefore, the geotechnical and geomechanical characteristics of such rock mass should be assessed through in situ investigation and numerical analysis to minimize future accidents during underground unloading excavation."

Jan 1, 2015

By N. L. Richards

In manufacturing for the 21st century, the first company to market often leads the pack in product development and sales. In this respect, manufacturing processes play an important role in transforming “raw materials” into a product(s) for sale to a customer. Thus it can be seen that upfront modelling of a design concept, or modelling of manufacturing processes in a plant, can play an important role in effectively ensuring the overall design and manufacturing route is carried out in an expeditious manner. In the paper various scenarios are considered with respect to modelling the microstructure and/or process, in various manufacturing processes. Also considered are the effects of service condition on the manufactured product in terms of creep and fatigue.

Jan 1, 2010

By G. Gu, B. Fang, R. W. Revie, M. Elboujdaini

Electrochemical behavior of an X-80 pipeline steel, including frequency-sweep electrochemical-impedance spectroscopy (EIS), time-sweep EIS at a constant frequency and open-circuit potential (OCP) monitor, was investigated using four-point bending specimens subjected to a stress-corrosion cracking (SCC) test in a near-neutral pH environment. The capacitive loop became smaller with test duration, revealing an increase in the corrosion rate. The resistance obtained in the constant-frequency EIS test showed two regions, of which the region with a remarkable decrease in resistance transformed into a region of slow decrease, whereas the capacitance increased with test time indicating that iron dissolution was fast at first, and then a corrosion product or film formed and covered the surface, leading to the pitting formation.

Jan 1, 2005

By Andrew Barnes

The adsorption capacity of peat collected from a proposed mine development in northern Sweden has been determined using laboratory column experiments in which peat was irrigated with a simulated (acidic) waste rock dump leachate. The simulated leachate was made using a hydrogen peroxide leach of composite waste rock from the proposed mine development. The waste rock samples were composited in proportion to their predicted extractable tonnage for the mine development in order to generate a more representative leachate solution for the waste rock facility. As expected the test revealed that the peat material shows a very high affinity for attenuation with greater than 70% of Co, 90% of Ni and 95% of Cu removed from influent solutions through the majority of the tests demonstrating the potential benefits in mine water treatment. In contrast, it was found that Fe is initially released from the peat at concentrations up to 100 mg/L and can mean potential problems for the water released depending on the receiving environment. The exact mechanisms for Fe release is uncertain, though it is suspected that ion exchange / competitive desorption is responsible. Inspection of the laboratory results and drainage data from the natural peat wetland receiving drainage during overburden prestriping and mine development at the mine site are comparable, confirm the validity of the experiments, and further emphasize the potential for future use of pre-stripped peat material in managing water quality.

Aug 1, 2013

By G. H. K. Pearse, R. P. Taylor

The Big Whopper, one of only four giant economic rare metal pegmatites worldwide, is set to become a producer of the highly valued lithium mineral petalite (LiAlSi4O10) used in glass, ceramics and the specialty glass-ceramics familiar as Corningware® and the new ceramic stovetops. The deposit has a strike length of 1.5 km, a width of up to 80 m and a resource, open in all directions, of 11.6 Mt, grading 25% petalite. It is amenable to open pit mining and Avalon Ventures Ltd. holds a patent on a flotation process that produces an exceptional quality petalite product. The project will also produce: superb quality Na-feldspar which, too, finds use in glass and ceramics; the unusual Rb- K-feldspar for high voltage porcelain insulators; tantalum, in high demand for electronics; lepidolite, an ore of rubidium; and mica and tin. A positive prefeasibility study has been completed and it remains only to undertake bulk sampling and a full feasibility study.

Jan 1, 2001

By D. J. MacKinnon, Kazi E. Haque

Ammonia present in a variety of mine/mill waste waters was almost completely oxidized to nitrogen by chloride mediated electro-oxidation. A closed circuit operation of preconcentration of ammonia on a suitable adsorbent (e.g. zeolite or a resin) followed by brine stripping of ammonia and electrolysis of the strip liquor seems to have sound technical, economic and environmental merits. The removal of ammonia, cyanide, cyanate or thiocyanate from a mine/mill waste water (e.g. gold mill), either individually or collectively, is also feasible by chloride mediated electro-oxidation technique. Further R&D investigations are necessary for the development of a closed circuit operation for the removal of ammonia, cyanide and thiocyanate; and also to obtain technical data for process cost estimates

Jan 1, 1996

By H. Jung

The microstructures and grain sizes of nanocrystalline Co and Co-1.1 wt % P alloys were characterized by X-ray diffraction. The corrosion properties of as-deposited and annealed Co-l.l wt % P alloys and pure nanocrystalline Co were studied in a deaerated 0.1M H2SO4 solution using electrochemical measurements and XPS surface analysis. Potentiodynamic polarization testing and impedance measurements revealed that an addition of P to pure nanocrystalline Co improved the anodic-corrosion resistance, however, this enhanced corrosion resistance was compromised by the heat treatment process at 350 and 800°C. The corroded surface of annealed nanocrystalline Co-1.1 wt % P at 350°C exhibited a more porous P-enriched layer compared with the as-deposited case. A sample annealed at 800°C corroded uniformly showing second-phase precipitates. The enhanced corrosion resistance of as-deposited nanocrystalline Co-1.1 wt % P was attributed to the elemental P on the surface that acted to hinder the anodic dissolution kinetics of surface Co following an initial selective dissolution of Co. However, at a higher anodic overpotential region, the superior corrosion resistance of Co-l.l wt% P alloys did not last because of the formation of a non-protective surface film consisting of mainly hypophosphite and phosphate as well as elemental P.

Jan 1, 2005

By G. Ladouceur

"Northgate Patino Mines produces a copper concentrate assaying 22% Cu. Moisture content of the product averages 12.5% H20 when dewatering with conventional vacuum disk filters. Recent smelter contracts reflect higher energy costs and increased moisutre penalty charges. This situation forced Northgate to investigate possible alternatives such as rotary dryers and pressure filtration. After laboratory testing, it was found that pressure filtration could economically meet the smelter's requirements. Pilot plant testing was then undertaken and confirmed the laboratory test results. Based on these findings, a model I.S.F. 1500 x 28/22 I.R. Lasta filter press was purchased.This paper describes the Copper Rand dewatering flowsheet the operation of the press and the economics of the process.IntroductionNorthgate Patino Inc. operates 2 und erground copper mines and a 3300 ton per day concentrator located in Chibougamau, Quebec, some 425 miles north of Montreal and 300 miles northeast of Noranda, Quebec.Copper concentrate is produced at a rate of 250 tons per day and trucked to a C.N. siding 10 miles from the mill site and then railed to the Noranda Smelter.Until early 1981, moisture content of the concentrate at 12.5070 was acceptable since smelter penalty charges were relatively low ($0.10 per ton per unit over 10070 moisutre). In January 1981, a new contract was signed in which the penalty was raised to $1.10 per ton per unit over 8070 . This and the increasing truck and rail costs justified the change-over from vacuum to pressure filtration . The Lasta I.S .F. 1500 x 28/22 was then purchased and installed, and operation of the plant started in December 1981."

Jan 1, 1987

By Karl J. C. Harries

"The Table of Contents that follows is only an example and is the Table of Contents from an actual negotiated agreement. It is merely intended to show how an agreement might be set out and the nature of possible provisions. As a negotiated agreement the format was dictated by the negotiations. It is not offered as a precedent of what should be contained in a joint venture agreement (“JVA”), the “proper” sequence of Articles, or a complete listing of the contents of joint venture agreements generally. The set-up used for an agreement should be decided by the parties and be one they consider flows in a logical and workable sequence. This example sets out the “deal” first, followed by the provisions relating to how work is to be carried out and then by administrative provisions necessary to make the agreement work. If you are more comfortable with, say, having the Committee provisions at the beginning, by all means have it drafted that way -- you are going to have to live with the agreement and work under it.Notes:1. The Table of Contents provisions appear in bold print. The italicized sections are annotations, which have been provided in some cases where the heading may not clearly describe the contents. They are not intended to be comprehensive, but refer to some specific matters that are considered to be of interest or to need some clarification.2. The subject matter of many of the articles and paragraphs is discussed or commented upon in the text of the book. Some of section cross-references have been provided. Such references are only to sections where the topic is a principal subject and no attempt has been made to provide a comprehensive indexing.3. Although this particular agreement is a three-party agreement, *B* and *C*, the Owners, are required to act as a unit (see para. 1.09. – § 8.44.), making the agreement effectively a two-party agreement. The parties insisted upon having a decision-making Committee and structuring the agreement accordingly. As is explained in § 8.11., such an arrangement is not recommended and can result in problems.5. See also §§ 8.24., 8.41. and 14.13. for discussions on tables of contents, summaries, and headings."

Jan 1, 2003