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The mechanism of thiosulfate decomposition and the products formed were investigated in the presence of pyrite or pyrrhotite in copper-ammonia solutions used for leaching gold. The presence of the sulfides significantly increased the decomposition of thiosulfate. The sulfide-surface-catalyzed oxidation of thiosulfate to tetrathionate by dissolved oxygen or the cupric tetra-ammine complex was proposed to be the dominant thiosulfate decomposition mechanism. The catalysis of the sulfides in this reaction could originate from their strong affinity for aqueous sulfur species and their semiconducting properties. Oxygen was found to be the initial driving force for thiosulfate decomposition in the absence of cupric ions and the driving force for the continuous decomposition of thiosulfate in the presence of cupric ions. Under an oxygen free atmosphere, the decomposition of thiosulfate was limited to reduce the cupric ions and the catalytic effect of the sulfides was also marginal. The dominant oxidative product of thiosulfate was trithionate in alkaline solutions especially in an oxygen rich or cupric ion rich environment. Tetrathionate was found in relatively smaller amounts in an oxygen and cupric ion deficient environment. Tetrathionate was not stable and would further decompose after extended periods. Trithionate concentrations increased almost linearly with time.

Jan 1, 2005

By Gabriel Voicu, Marc Bardoux, Ross Stevenson, Nuno Machado, Jean Lafrance

"Abstract - Paleoproterozoic gold is found in two different volcano-sedimentary sequences and intrusive bodies separated by 600 km within the Guiana Shield. The 2148 Ma St-Élie granite intruded volcanic-arc sequences of the Paramaca Group, whereas the 2096 Ma Omai stock penetrated backarc/ island-arc sequences of the Barama-Mazaruni Group. Positive ?Nd values suggest that both suites lack Archean crustal contaminants, which is consistent with an origin in an oceanic arc setting.The St-Élie deposit is characterized by quartz-dominant vein systems with minor metallic minerals, represented chiefly by pyrrhotite and pyrite. Biotite, calcite, and chlorite are the main gangue minerals. The alteration haloes at St-Élie feature a strong potassic zone, which is absent at Omai. The ore-controlling structures are ductile and the vein emplacement is related mainly to contemporaneous, high-angle ductile shear zones. The St-Élie deposit formed at temperatures >350°C. The stable isotopes values are compatible with a magmatic or metamorphic source.The Omai deposit is characterized by quartz-dominant vein systems with minor metallic minerals, represented mainly by pyrite. Ankerite, scheelite, albite, and chlorite are common gangue minerals. The vein emplacement is syn- to post-deformation and it is related mainly to brittle shear zones with low-angle, stockwork networks and breccia zones. The Omai deposit formed in a temperature range between 250°C and 170°C, much lower than the St-Élie deposit. The stable isotope values are compatible with mixing between deep-seated fluids of metamorphic or magmatic origin with surface- derived fluids.These differences between St-Élie and Omai are interpreted in terms of their depth of formation. Alteration patterns, structural elements, and paragenetic assemblages indicate that the gold at St-Élie was most probably emplaced at a mesozonal depth, whereas the Omai setting yields evidence for epizonal conditions."

Jan 1, 1999

By A. Roy, T. LeBel, P. Coursol, P. Lind

At the early stage of a mining project, small amounts of concentrates are available for testwork. For gold concentrate or ores containing significant arsenic levels, batch bench scale roasting is often unreliable, leading to highly variable gold recoveries to be used in the project’s financial justifications. With an appropriate bench scale unit using continuous feeding and residence time control for solid and gas phases, reliable numbers can be obtained at small scale with only a few hundred grams per test condition. This paper describes the development of a pilot fluid bed roasting unit by Kingston Process Metallurgy Inc. (KPM) to perform representative trials on gold concentrates containing arsenopyrite, arsenian pyrite and carbonaceous components. Calcines produced under different conditions were characterised by chemical analysis and electron microprobe; the calcine microstructure obtained is described. The most important parameter affecting gold recovery is oxygen content in the roasting atmosphere, with the lowest controlled oxygen level giving the highest gold recoveries. Higher local temperatures in the bed may cause the formation of molten glassy phases which can also reduce the gold recoveries significantly. The impact of roasting conditions in the two inch fluid bed is compared with commercial results obtained in full scale operation.

Jan 1, 2014

By D. A. Bordin, C. J. Newman, R. J. St. Eloi

"The requirements for a metallurgical acid plant treating smelter gases are both unique and demanding in terms of sulphur dioxide treatment and emission control. Since start up in 1981, the copper smelter at the Kidd Creek Division of Falconbridge Limited has undergone several major expansions. The expansion and modification of the acid plant has been an integral part of this process. Both production demands and government regulations dictate that this metallurgical acid plant be unique in terms of operating flexibility. The variable capacity to treat a wide range of sulphur dioxide concentrations, and the operating flexibility to control emissions are the topics of this paper.INTRODUCTIONThe Kidd Creek Division of Falconbridge Limitied is a base metal mining and metallurgical complex located in Timmins, Ontario. The discovery of the original copper-zinc-silver orebody was announced in April, 1964. Mining operations began in 1966 with a 9000 tonne per day concentrator coming on stream in November of that year. In April 1972, a 108 000 tonne per year zinc plant was commissioned. Over the years the facilities have been expanded, such that the concentrator now has the capacity to process 13 000 tonnes of ore per day . To expand zinc production, the world's second installation of the Cominco/Sherritt pressure leaching facility was completed in 1983 to bring total zinc production capacity to 125 000 tonnes per year. In 1973, serious planning for a smelter operation began. In early 1975, after studying both continuous smelting and flash smelting processes, a decision was made to proceed with the technology offered by Mitsubishi Metal Corporation of Japan. The Mitsubishi Continuous Smelting Process was to be used for the smelter and the Onahama No.3 tankhouse technology for the copper refinery.The smelter, which uses the Mitsubishi Continuous Smelting Process for the continuous production of blister copper from concentrate, went on line in June 1981. It has been expanded from its original capacity of 60 000 tonnes to 100 000 tonnes per year of copper.From the very early design stages for the metallurgical complex, the company had adopted a policy of constructing and operating modern plants which would meet existing and anticipated environmental standards. With this in mind, the decision was made to utilize the proven technology of fixing sulphur dioxide emissions, in the form of sulphuric acid. A 636 tonne per day single absorption contact acid plant was built to serve the zinc plant in 1972. In 1981, an 883 tonne per day double absorption contact plant was built to serve the needs of the copper smelter. The copper smelter acid plant has since been expanded to a design capacity of 1692 tonnes per day and it is the main focus of this paper."

Jan 1, 1989

By J. Kalejta

Ever increasing depth of mineral extraction presents a challenging environment for hard rock underground mines. High in-situ stresses and associated seismicity with potential rockburst hazards are the major decisive factors contributing to the choice of a ground support regime. Conventional ground support systems, designed primarily for static loads, are not always capable of providing safe working conditions for underground personnel in seismically active mines. Systems specifically developed to resist dynamic loading and allowing for larger deformations are therefore preferred alternatives. High-tensile chain-link mesh has a proven record of successful use in open cut operations in various rockfall barrier installations due to its high energy absorption capacity. It has also been used in underground operations in various parts of the world. This paper describes a method of mechanized installation of a chain-link mesh evaluated at the Kiruna mine in Sweden and South Deep Mine in South Africa. A purpose-built mechanized roll mesh handler was used in this evaluation. The handler is compatible with all standard multi-boom underground drill rigs and is operated utilizing the hydraulic circuit normally used for the feed arrangement. A number of key performance indicators have been identified as success criteria: ??A 30-50% faster installation compared to the conventional methodology ??The mesh should sustain any blast damage when applied to the blasting face ??No unraveling of the mesh when cut ??No failure of mesh under normal conditions Although the energy-absorbing mesh combined with yielding rock bolts is a ground support system of choice for rockburst prone conditions, the operational upsides recognized during the evaluation imply that this product can also be competitively used in less demanding ground conditions where customarily weld mesh or shotcrete are used as a primary surface support. The main conclusion: a fast, safe and fully mechanized installation.

Aug 1, 2013

By J. Palarski

In the Polish coal mining industry, the use of mine waste in underground backfill has been the most common means of providing ground support to minimize surface subsidence, increasing extraction ratios, and reducing the quantity of waste for surface disposal. Over the last decade attention has been focused on the use of different waste as filling material of underground workings and grouting of roof fall rocks in caving area. In the paper, a brief history of the development of fill technology in Polish coal mining industry is presented. Next, the paper discusses various criteria that should be taken under consideration in the preparation process of a fill slurry and grout, fill distribution systems, mining geometry and placement methods. Moreover, in the paper evaluation of the potential of utilizing coarse and fine waste as a resource material in the production of a backfill slurry and grout for filling and injection in abandoned mines is presented.

May 1, 2007

By J. R. Kadambi, E. Kucukal, J. Furlan

"Hydrocyclones are used in various industrial applications, including mineral processing and tailings management, to separate or classify solid particles and/or liquid droplets from multiphase feed. The fluid flow in a hydrocyclone (used in mineral processing) was investigated numerically and experimentally using particle-image velocimetry (PIV) and refractive index matching techniques. Two turbulence models were used in the calculations: the k–? model and the Reynolds stress model. Particle image velocimetry measurements were taken at various spatial locations along the cyclone. Computational results were validated globally using pressure and flow-rate readings at the boundaries, and locally by comparing the PIV velocity-vector maps and profiles.RÉSUMÉ On utilise les hydrocyclones dans diverses applications industrielles, dont la minéralurgie et la gestion des résidus, pour séparer les particules solides et/ou les gouttelettes liquides de l’alimentation polyphasée, ou pour les classifier. Une étude numérique et expérimentale sur l’écoulement des fluides dans un hydrocyclone (dont on se sert en minéralurgie) a été menée à l’aide des techniques de vélocimétrie par images de particules (PIV, de l’anglais particle image velocimetry) et d’appariement des indices de réfraction. Deux modèles de turbulence ont été utilisés dans ces calculs, à savoir le modèle de turbulence k–? et le modèle aux tensions de Reynolds (RSM, de l’anglais Reynolds stress model). La valeur de la PIV a été mesurée à diverses positions spatiales le long du cyclone. Les résultats de ces calculs ont été validés globalement à l’aide de relevés des pressions et du coefficient d’écoulement d’une extrémité à l’autre de l’hydrocyclone, et localement à des coordonnées spatiales spécifiques en comparant les cartes et les profils du vecteur vitesse PIV."

Jan 1, 2017

By Rodrigo Craig Cerello

The Brazilian economy has always presented a strong correlation with the mineral activity. Since colonization days, due to the territorial expansion caused by the explorers search for gold, mining in Brazil became a basic sector of national economy. Currently, the Brazilian mineral sector¹ estimates a 550% production increment (Figure 1A) in the last 10 years, reaching the US$ 50 billion value, reflecting the increased global demand for raw materials from mineral origin. According to the Brazilian Constitution², mineral resources belong to the Federal State and, consequently, their exploitation must be authorized, under penalty of engendering federal crime. Furthermore, activities of this nature are prone to cause environmental degradation such as, but not limited to, deforestation, pollution, soil deterioration and water contamination. The GPEMA represents the forensics group of the Brazilian Federal Police responsible for the technical analysis of traces related to crimes against the environment and consequently, illegal mining cases.

Aug 1, 2013

In the leaching and recovery of gold from copper containing gold ores using cyanidation, some copper minerals also dissolve which can have a detrimental effect on the process efficiency and economics. There are also environmental concerns with current operations discharging cyanide and copper cyanide species into tailings dams, and strict regulations prohibit this for greenfield plants. Cyanide destruction however is not an economic option for new plants treating copper-gold ores. This paper evaluates a potential recovery process to overcome the copper cyanide problem. Despite gold dissolution occurring in copper cyanide solutions having no free cyanide, gold recovery from ores is lower compared to free cyanide. Thus, cyanide addition has to be optimised to maximise the gold recovery whilst endeavouring to eliminate free cyanide at the completion of leaching (CN:Cu less than 3:1). Subsequently, copper cyanide can be recovered using activated carbon. The loaded copper cyanide is easily recovered from the carbon with a cyanide soak and distilled water wash such that the eluted CN :Cu ratio is less than 4:1. The copper could be recovered efficiently by electrowinning, by decreasing the pH of the eluant to 5. The remaining cyanide solution, after electrowinning, is then neutralised to form NaCN and recycled.

Jan 1, 2005

By Gary M. Poxleitner

Skip/Hoist ?Vertical Advantage of Hoist ?High capital ?High operating cost Trucks Trucks ?Flexibility of ramp ?Low capital ?High operating cost Conveyor Inclined High capital ?Low Cost to run ?Continuous Production ?High Capacity ?Transfer pointsMax Grade: +32%

Feb 1, 2008

By Walter Valery, Sergio Vicuna, Roberto Valle, Hamer Arevalo, Ben Burger, Lui Vargas, Alex Jankovic, Jim Seidel, Eduardo Nozawa

This paper describes the design, the first three years of operation and optimization of a large, single stage SAG mill at Minera Yanacocha’s Gold Mill facility located in northern Peru. The Gold Mill was commissioned in March 2008 with a 32’ x 32’ EGL, 16.5MW single stage SAG mill, to process 5 million tonnes per annum high grade oxide Au/Ag ore. Operational control, feed size distribution, grinding media, mill liner, grate and pulp lifter optimisation have allowed the mill to operate 15-30% above design throughput rates, but with a product P80 coarser than design. As part of the optimization, full grinding circuit surveys were conducted. Historical operating data and survey data were analyzed and used to evaluate possible circuit changes and determine alternative operating strategies. A number of changes were implemented which allowed the SAG mill to operate similarly to a large ball mill and achieve finer mill product that was closer to design. This paper summarizes life to date data analysis and improvements made by Minera Yanacocha as well as the grinding circuit optimisation study conducted by Metso Process Technology and Innovation.

Jan 1, 2012

By M. S. Moats, C. M. Campbell

Samples of a high impurity (90.05 wt. % Cu, 4076 ppm Pb, 1939 ppm As and 635 ppm Bi) commercial copper anode were characterized and then electrorefined in a laboratory scale cell. Anode inclusions were examined using backscatter mode scanning electron microscopy and energy dispersive spectroscopy. Hundreds of inclusions were measured for size, morphology and composition. Commonly found inclusions were copper oxide (Cu2O), complex oxides (Cu-Pb-Bi-As-O) and copper selenides/tellurides. The weight percent of lead and arsenic increased with increasing inclusion size up to 4- 5 microns. During electrorefining, starter sheet ductility was negatively impacted by thiourea addition. The importance of arsenic (V) concentration on the electrolyte concentration of bismuth was observed. INTRODUCTION Copper electrorefining is a commercial process used to produce the majority of the world’s refined copper. During this process, impure copper anodes are dissolved electrolytically, and high purity copper is deposited on cathodes. As the anodes dissolve, the impurities either accumulate in the electrolyte or report to solids that form on anodes surfaces or at the bottom of the refining cell. These solids are called slimes. Slimes contain precious metals and are collected for further processing. Slimes are also an important outlet for problem impurities such as lead, antimony and bismuth. The electrorefining process is operated in such a way to encourage the deportment of these elements to the slimes. Impurities in copper anodes have been studied extensively by Chen and Dutrizac (1990, 1993 and 2005). The most common impurities found in modern copper anodes include: Ag, As, Au, Bi, Fe, Ni, O, Pb, Sb, Se, Sn and Te. Impure copper anodes are produced by pyrometallurgical methods and have purities ranging from 97.7–99.7% Cu (Moats et al., 2019). The composition ranges of commercial copper anodes from the 2019 worldwide tankhouse survey are given in Table 1. The concentrations of anode impurities vary widely dependent on the source material and prior processing steps. Based on the work of Chen and Dutrizac, both gold and silver are predominantly found in solid solution within the copper grains while a minor amount of Ag can be found in Cu2(Se/Te) inclusions. Nickel is entirely soluble within the copper grains up to anode compositions of 2500–3000 ppm Ni; above which NiO and kupferglimmer phases are formed (Chen & Dutrizac, 1990). As, Bi, Pb and Sb are found in solid solution within copper and within oxide inclusions typically found along grain boundaries. Oxides are formed due to the presence of 0.13-0.18 wt. % O (Chen & Dutrizac, 1990). This is because during solidification of the cast anodes, impurities are enriched in the liquid phase as the copper grains nucleate and grow. The inclusions form from the last liquid to freeze, which is typically along grain boundaries (Wenzl & Filzwieser, 2007; Wenzl, Filzwieser, Mori & Pesl, 2008).

Jan 1, 2019

By C. Groccia

As the search for new ore bodies drives mines to be developed at greater depths, the associated high stress environments present challenges for rock support design. Excavations in highly stressed brittle rock are often subject to large volume increases due to rock failure, a phenomenon known as rock mass bulking, which can result in significant wall convergence. Support systems need to be designed to minimize the amount of bulking and to accommodate large wall convergences. In order to design such a support system, empirical guidelines are often used to predict the amount of bulking. However, the empirical guidelines that are currently available are based on a limited number of case studies and consider few input parameters, which may result in an inaccurate bulking assessment. This paper describes methods of collecting quantitative field data at Creighton mine in Canada to better understand rock mass bulking and to further develop the empirical guidelines for bulking assessment for tunnels in highly stressed grounds. Measuring

Aug 1, 2013

By Shila Jafari, Mari Lundström, Aleksei Kritskii, Pia Sinisalo

A typical process adopted at nickel plant is the processing of nickel-copper mattes and converter mattes using the following technology: pressure oxidative leaching (POX), solvent extraction (SX), electrowinning (EW), cobalt recovery, and solutions purification. As a result of multi-stage atmospheric and autoclave process leaching, copper-nickel separation is achieved. Cobalt and nickel are further separated by SX. Copper in the process can be removed as copper cake (Cu-cake), which is a by-product with high content of valuable metals. In the current paper, a method combining atmospheric and pressure leaching of Cu-cake in sulfuric-acid media is discussed. Suggested method allows to obtain high copper extraction (>98%), with leach residue containing precious metals and PGMs. Sulfuric acid media was chosen to make the suggested technology adaptable for the primary POX-SX-EW circuit. The initial Cu-cake was analysed and a range of process parameters (t = 25–190°C; PO2 = 0–7 bar) investigated to achieve the optimal conditions for leaching process at the ambient as well as at increased pressure. As a result, an initial process block diagram for the treatment of Cu-cake with high copper leaching efficiency and low metal losses is provided. INTRODUCTION The conventional technology for nickel sulphide ore processing includes the following main stages: froth flotation, matte smelting and converting. The subsequent processing of nickel converter matte is possible using fundamentally different approaches - hydrometallurgical (Llanos, Queneau & Rickard, 1974; Rademan, Lorenzen & Van Deventer, 1999; Kshumaneva, Kasikov, Neradovskii & Belyaevskii, 2009; Dutrizac & Chen, 2013) and pyrometallurgical (Tsymbulov, Knyazev, Tsemekman & Golov, 2007). Hydrometallurgical approach in comparison with pyro-process has several advantages, such as reduced environmental load, reduced PGM losses, increased copper and nickel extraction. Typically, hydrometallurgical technologies include leaching, solvent extraction as well as nickel and cobalt recovery in metallic form by electrowinning or hydrogen reduction or as valuable metal salts via crystallization process (Crundwell, Moats, Ramachandran, Robinson & Davenport, 2011).

Jan 1, 2019

By Tom Shumka

All mineral processing facilities that use girth gear driven mills need to inspect the gear teeth on a routine basis, whether it is every six months or every three years. The inspection frequency depends upon gear tooth condition, and the objective is to ensure operational integrity of the gear teeth. Conventional methods such as magnetic particle testing, visual inspection, or dye penetrant examinations rely heavily on interpretation. At best, these techniques can determine whether a defect exists, but are unable to provide information on defect severity. This paper describes the use of combined Eddy Current Array (ECA) and Alternating Current Field Measurement (ACFM) to provide a complete survey of all surface breaking indications on the whole gear tooth depth. This method accurately determines the size, length and depth of any cracks found on the surface.

Jan 1, 2012

By E. Lehtila, J. J. Talja, R. Jahila

Kopar Oy is acknowledged for engineering and manufacturing of robust systems for bulk material handling, especially at power plants and non-ferrous smelters. We have over thirty years of experience with systems specifically designed for hot and abrasive conditions, aiming at low cost of ownership, low operational expenses and high availability. Although Kopar has numerous applications in mechanical conveying, there is an increasing number of pneumatic conveying applications at copper smelters. They relate to conveying of concentrate, and primary and secondary flue dusts. Challenges of pneumatic conveying for concentrate are mechanical and do relate to broad particle size distribution and high abrasivity of the concentrate and the silica. Therefore, special attention shall be paid to system design and ceramically lined bends in the pipeline. Challenges of pneumatic conveying of primary flue dust relate predominantly to material stickiness and poor flowability which are mainly due to fine particle size and formation of sulphates and furthermore, crystalline water. Additional challenges of secondary dust, the white converter dust, are primarily due to the extremely fine 0.1–1.5 µm particle size and problems which come with this. Effect of material characteristics like size distribution, morphology and chemical composition in pneumatic conveying are discussed in detail. INTRODUCTION Fine materials like concentrate, feed mix, flue dusts (from waste heat boiler and electrostatic precipitator) and secondary dusts need to be conveyed at smelters. Both horizontal and vertical conveying and combination of those are used. For the purpose, both mechanical and pneumatic conveying are applied. Most widely used equipment are drag chain conveyors and various combination of pneumatic systems, e.g. air lift, dense-phase and dilute phase pneumatic conveyors. Kopar has 30 years’ experience with multiple material handling systems. Furthermore, acquired companies like Elmomet Oy and SITE Oy (both currently fully merged and integrated into Kopar Oy) have even longer history, especially in pneumatic conveying. It is commonly known that the finer the dust the more difficult it is to be conveyed pneumatically. Sulfates with crystal water makes it all even more difficult, if not ineligible. Challenges related to pneumatic conveying of various fine materials is discussed in detail in the paper.

Jan 1, 2019

By Kenta Kusunose, Dadang Sundana, Ahmad Munib Fikry, Yosuke Unno

PT Smelting has operated the Mitsubishi Process in which feed materials are charged into the S- furnace through top lances using a pneumatic conveying system comprising 6 feeding tanks (S-Feeding Tanks). Each S-Feeding Tank was designed as a batch machine and had been operated in a batch mode so that feed materials are conveyed 70% of the operating time (conveying time). An S-Feeding Tank was revamped in August 2016 in order to attempt to achieve 100% conveying time during operation, aiming to reduce the furnace draft fluctuations and melt temperature fluctuations leading to reduced copper losses to slag and refractory wear on the sidewall in the melt zone. After two-year operation with some adjustments and modifications, it was concluded that the new system works as expected. During scheduled major shutdown in November 2018, the same modification was applied to all other 5 feeding tanks as the first one, while several modifications other than the S-Feeding system were also conducted for the purpose of expanding the capacity of the smelter. INTRODUCTION PT. Smelting (PTS) Gresik Copper Smelter and Refinery is located 30 kilometers north of the city of Surabaya, East Java major port. PT Smelting equity partners are Mitsubishi Materials with 60.5%, PT. Freeport Indonesia with 25%, Mitsubishi Corporation RtM Japan Ltd. with 9.5% and JX Nippon Mining and Metals corporation with 5.0%. PTS was established in February 1996 and started commercial operation of the Mitsubishi Process in 1999. The Mitsubishi Process is a unique technology which connects 3 stationary furnaces, namely the Smelting furnace (S-furnace), Slag-Cleaning furnace (CL-furnace) and Converting furnace (C-furnace) by covered launders. These features result in savings in manpower and energy, and make the process more environmentally friendly since there is no ladle transfer of melt. Figure 1 illustrates the outline of the Mitsubishi Process.

Jan 1, 2019

By Terry Aben

Outline ?Review of standards that can be used to identify current coating conditions and optimal points to perform coating maintenance. ?Identify how standards can be used to extrapolate the future condition of coatings to achieve predictive maintenance planning. ?Demonstrate how the above can be combined with project estimating to generate a data driven, quantitative, predictive, risk-based asset integrity maintenance program for Protective Coatings. The Value of Asset Integrity Programs ?Maximize the benefit produced from the investment in maintenance spending. ?Get the best bang for your buck! ?Don?t perform maintenance work before it is necessary ?Money is invested early with no increase in the service life extension. ?Don?t delay until it is too late. ?Planned Maintenance is far less costly than Reactive Maintenance. ?Identify the Optimal Point for Maintenance.

Nov 1, 2011

By Tom Shumka

All mineral processing facilities that use girth gear driven mills need to inspect the gear teeth on a routine basis, whether it is every six months or every three years. The inspection frequency depends upon gear tooth condition, and the objective is to ensure operational integrity of the gear teeth. Conventional methods such as magnetic particle testing, visual inspection, or dye penetrant examinations rely heavily on interpretation. At best, these techniques can determine whether a defect exists, but are unable to provide information on defect severity. This paper describes the use of combined Eddy Current Array (ECA) and Alternating Current Field Measurement (ACFM) to provide a complete survey of all surface breaking indications on the whole gear tooth depth. This method accurately determines the size, length and depth of any cracks found on the surface.

Jan 1, 2012

Productivity and efficiency of diesel-powered underground trucks and LHDs can be enhanced through the application of a range of advanced technologies. In addition, these machines are subject to ever more stringent emissions control requirements. This paper will review how various technologies can improve usability, maintainability, and performance of LHDs, through a number of examples. The use of instrumentation and monitoring to understand the role of operator practice on mucking efficiency, as well as the use of finite-element analysis to evaluate structural design, and the use of control techniques to modify operator inputs and hence decrease power consumption, will be presented.

May 1, 2002