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By John Vickers, William H. Hover, Paul C. Schmall

"Any sudden subsurface issue that threatens the stability of existing buildings or infrastructure is cause for immediate investigation and prompt remedial action. Nowhere is this more true than the nation’s dams and levees. A breach of any kind, no matter how small initially, has the potential to be catastrophic and impact a wide downstream area. Addressing the problem quickly and effectively is therefore critical. When a turbid water discharge developed from a rock drainage embankment at the toe of the earthen dam impounding Cannonsville Reservoir, near Deposit, NY, the source of the problem was quickly identified as resulting from an artesian water release from an underlying permeable silty sand and gravel formation during drilling of three exploratory boreholes in preparation for construction of a hydroelectric plant at the downstream toe area of the dam facility. Work was halted, intense 24-hour monitoring was implemented, and as a risk reduction measure NYCDEP began to draw down the reservoir’s total storage at a rate of a billion gallons per day. Input sought from contractors within the geotechnical community helped result in the design and development of a deep well system to control the artesian pressure. Once this primary objective was accomplished, modified compaction grouting was performed at the borehole locations to densify loosened soils, fill any voids created by the discharge activity, and seal off the permeable aquifer. This paper discusses the dewatering program, specialized drilling techniques required, monitoring and verification of pressures within the dam, and the grouting program.BackgroundCannonsville Dam, owned and operated by the New York City Department of Environmental Protection (NYCDEP), is located in Deposit, New York on the West Branch of the Delaware River and impounds the Cannonsville Reservoir. Built between 1959 and 1964, the dam has an impervious central and upstream core zone keyed into the glacial till foundation, a semi-pervious downstream embankment zone, and a rockfill toe and is approximately 2,800 ft (853.4 m) long and 175 ft (53.3 m) high. The dam is formed by two embankment sections. The left section forms the main embankment blocking the main river channel, while the right section is constructed over a topographic saddle or low ridge. Reservoir level is actively influenced by withdrawals through the West Delaware Tunnel, based on water supply need. Under normal circumstances, water is continuously discharged downstream to the Delaware River."

Jan 1, 2016

By Taekhee Lee, Steven Mischler, Shawn Vanderslice

Diesel-powered equipment is widely used in the underground mining industry and their popularity results from properties including efficiency, versatility, reliability, and durability. In the U.S. approximately 7,700 diesel engines were used in 177 underground metal and nonmetal mines as of 2005 [MSHA 2005], and these numbers have likely increased since that time. Diesel engines have been shown to be a major contributor to submicron carbonaceous, respirable, and total particulate mass in the air of underground metal mines [Zielinska et al. 2002, McDonald et al. 2003], and their extensive use results in approximately 13,000 underground metal/nonmetal (M/NM) miners (MSHA 2005) in the U.S. being potentially exposed to aerosols and gases emitted by diesel engines (MSHA 2001, MSHA 2006). Exposure to diesel exhaust has been linked to adverse health outcomes including cancer, cardiovascular, and respiratory diseases (Attfield et al. 2012, Silverman et al. 2012), and in 2012 diesel exhaust was categorized by the International Agency for Research on Cancer (IARC) as a Group 1 human carcinogen (IARC 2012). Exposure to diesel particulate matter (DPM) is especially concerning for underground miners since underground mine environments have been shown to have some of the highest levels of diesel exhaust in the U.S. (EPA 2002, MSHA 2001, MSHA 2006, Pronk et al. 2009). Due to the potential for elevated DPM concentrations in mines, the Mine Safety and Health Administration (MSHA) promulgated a rule to limit exposures of metal/ nonmetal underground miners to DPM to an eight-hour time-weighted average (TWA) of 160 μg/m3 total carbon (TC) (MSHA 2001, MSHA 2006, MSHA 2008). Since this rule went into effect, DPM exposures have been reduced, but are still elevated when compared to other occupations (Pronk et al. 2009, Noll et al. 2015). MSHA compliance data between 2005 to the present show that underground blasters represent 21% of all DPM overexposures in M/NM mines and are one of the highest exposed professions in mining often resulting from low ventilation in the area where blasters are working. Because mines have difficulty controlling DPM in these low ventilation areas, additional control technologies may be needed to reduce exposures. Administrative controls, where miners work on off schedules or upstream of diesel vehicles to avoid the exposures to DPM (Noll et al. 2015) is one possibility, but these types of solutions are not always feasible or practical. A canopy air curtain is another potential control technology to help reduce exposures of blasters to DPM. Listak and Beck (2012) showed that this control technology reduced respirable dust concentration under a roof bolter’s canopy by 67%–75% and recommended air velocities greater than 0.5 m/s for dust reductions of greater than 50%. Additional work showed that a canopy air curtain could be designed for a shuttle car, and some initial testing by the National Institute for Occupational Safety and Health (NIOSH) showed reductions of respirable mine dust between 66% to 70%. As seen in Figure 1, the canopy air curtain delivers clean air over the operator’s breathing zone. A fan draws in air through a filter to capture the dust and then supplies clean air beneath the canopy where a miner is working. The use of the canopy air curtain to reduce exposures to diesel particulate matter was first discussed by Noll et al. (2020). In this study the diesel canopy air curtain (DCAC) reduced the DPM concentrations under the canopy by up to 90%. For this research the DCAC was designed to attach to the basket cover of an ammonium nitrate fuel oil ( ANFO) loader (Figure 2) and provide clean air blowing over the miners as they work in the basket. The initial tests used clean air drawn from the mine’s intake and did not try to filter the DPM from the air. Filtering DPM has extra challenges when compared to filtering mine dust particles. The particles of DPM are smaller (submicron and nanometer) than dust particles (greater than 1 micron); therefore, the filtration system must be adjusted to capture submicron particles. A MERV 13 filter was used in previous canopy air curtain research on mine dust control, but this filter is only designed to capture 50%–75% of submicron particles, and this capture efficiency is too low for removing DPM, so a higher efficiency filter is needed. Higher efficiency filters increase the pressure across the filter media which results in decreased airflow or leaks around the filter and reduces the effectiveness of the control for protecting miners from DPM. The optimal filter needs to capture DPM particles at a high efficiency while still allowing the needed airflows to prevent contaminated air from entering the miner’s breathing zone. Listak and Beck (2012) recommended velocities greater than 0.5 m/s for dust reductions of greater than 50%. However, airflows too high have been shown to reduce miners’ thermal comfort; Roghanchi et al. (2016) suggest the optimal velocity for thermal comfort is between 1–2 m/s. Thus, airflow over the miner should be limited to the range of 0.5 to 2.0 m/s. This current study presents the results from research evaluating the reduction of DPM concentrations, under the DCAC, when using a higher efficiency filter (MERV 16) to remove DPM from the DCAC airstream.

Feb 1, 2024

Cansolv® S02 Scrubbing Technology was described in a paper in Copper/Cobre 03. Four years on, the technology is operating at a full scale production facility.Hindustan Zinc Limited expanded their capacity by installing the AUSMELT process. The process proceeds through smelting, slag reduction, slag cleaning and holding stages sequentially in the same vessel, resulting in widely varying off gas characteristics. The off gas is suitable for treatment is a conventional acid plant for a modest proportion of the day, but at other times produces off gas too high in S02 to be discharged to atmosphere. Cansolv® S02 Scrubbing Technology was identified as a means of effectively removing the S02 down to low levels from the off gas during all stages of the pyrometallurgical process. Furthermore, the Cansolv® S02 Scrubbing System Technology produces high purity S02 that allowed for the captured S02 to be directed to an existing acid plant, avoiding the capital cost of new acid making capacity.

Jan 1, 2007

By Valérie Léveillé

As new legislation drives to lower SO2 emissions from metallurgical plants, plant managers face the challenge of keeping their costs under control. The Cansolv® SO2 Scrubbing System has been broadly adopted in the non-ferrous industry as a cost effective solution for smelter operators to meet the new SO2 emissions targets. The Cansolv® SO2 Scrubbing System is an amine-based regenerable process that selectively absorbs SO2 from a variety of gases, including dilute smelter gases, such as furnace and converter gases. The system produces a pure, water-saturated SO2 byproduct stream, which can then be directed to the front end of a sulfuric acid plant for conversion to sulfuric acid. When deployed in a smelter complex, the Cansolv® SO2 Scrubbing System may also be used to process acid plant tail gas, allowing single absorption sulfuric acid plants to achieve emissions an order of magnitude lower than that of a double absorption acid plant with a lower capital investment. Depending on inlet gas temperature SO2 emissions in the treated gas can be controlled to as low as 55 mg/Nm3. This paper will describe some of the applications where customers have or are planning to use the Cansolv® SO2 Scrubbing System and what as well as which features and cost advantages for the treatment of smelter gases were key to the technology choice.

Jan 1, 2009

By L. D. Frink

THOSE actively interested in mining are fully aware of the ever-increasing difficulty of making conditions such that efficient work can be clone in underground openings, especially as higher rock temperatures are encountered in depth. This is also true where an effort is being made to cut down the burden of overhead expense by working headings 24 hr. in a day if blasting is done as often as is possible in that time. That the conditions resulting from both these causes have driven the native-born Americans from the mines and that their places have been taken by less efficient foreigners is a fact that we must all admit. The great war now being fought in Europe and the educational qualification clause written into our immigration law by the last Congress will probably limit very materially the supply of labor, such as we are now using in our mines, and will force upon mine operators the necessity of making this work appeal again to Americans. Metal tubing, with blower or exhaust fans, has long been used in supplying air to dead ends where natural ventilation is impossible, or in driving the smoke from such places, or in doing both, as the need might be. Here in Butte we have now come to use canvas tubing very extensively and find that it has many advantages not possessed by the metal. The use of flexible tubing is not new, but it has not been generally used in mining operations. Recent improvements, however, in the canvas itself and in the jointing of sections and manner of suspension have so increased its usefulness that it promises to add much to the efficiency of mining. There is now on the market a product that is impervious to air, is fireproof, and has a system of jointing which, permits it to be put up or taken clown in a few seconds. In this article an effort will be made to explain the manner in which canvas tubing is being used in the North Butte company's operations at Butte, Mont. The accompanying photographs will, I hope, help make clear what may be done with this material.

Jan 1, 1918

By Ron Light, Doug Applett

"HistoryThe Nanisivik mine began operation in October 1976 as the world's most northerly metal mine and the first permanent industrial project in the Canadian High Arctic. Located 700 km north of the Arctic Circle on Baffin Island's Strathcona Sound, exploration by Texasgulf Inc. between 1957 and 1970 had outlined the ore deposit. In 1974, Nanisivik Mines Ltd. was formed with Mineral Resources International, the Government of Canada, Metallgesellschaft and Billiton being shareholders, and Strathcona Mineral Services Ltd. providing project management. In 1996, Breakwater Resources purchased the mine from Alberta Energy Corporation Limited which had recently acquired the assets of then owners Conwest Exploration Ltd.Ore DepositThe main ore deposit is very flat, approximately 80 m in width and varying in thickness from 3 m to 16 m. The length of the deposit is approximately 3000 m with satellite zones located on the perimeter of the main zone. The economic mineralization is sphalerite with minor galena and silver. The sphalerite and galena are coarse grained and associated with pyrite as the main gangue component with minor inclusions pf dolomite and calcite within the deposit. The deposit being hosted in a permafi·ost environment creates a number of challenges. Dry drilling is employed in room and pillar production drilling. The permafrost aids in the stability of both the pillars and the back."

Jan 1, 2000

By Derek T. Novotny

Blasting cap precision is of major importance to advanced blast design. New technologies have introduced the use of microchips within detonator casings in the hope that the electronic control of the timing element will increase the accuracy of the cap and therefore improve the results of perimeter control blasting applications. The electronic detonators have proven to be accurate in timing tests done to date. They boast cap scatter results to microsecond accuracy, but the question is, does this degree of accuracy actually prove to be beneficial during practical use in the industry, or are conventional technologies applicable.

Jan 1, 1998

By L Neems

In conjunction with Orica Explosives, Worsley Alumina have managed a program of continuous improvement to their cap rock blasting over the last two years. Blasting conditions are challenging because of the hard and shallow nature of the material. Blasting costs must be controlled and the environmental consideration of noise and dust is critical. Worsley have sought to determine the optimum balance between drilling and blasting costs and fragmentation. As the cap rock has few inherent weaknesses, loader productivity is strongly controlled by the degree of fragmentation from blasting. The optimum blasting solution is also constrained by maintaining airblast levels at the surrounding residences below 115 dBL . The major blast design parameters optimised during the program were stemming type, stemming length, powder factor and blasthole diameter. A series of carefully managed trial blasts were fired during 1997 and 1998 to quantify the effect of these parameters. Fragmentation was digitally measured using OricaÆs Powerseive G technique. Shovel productivity, airblast levels and blasting costs were also quantified. As a result of the project, Worsley now have an increased knowledge of the key parameters driving blast performance, and their consequent impact on downstream processes, the environment and total mining cost.

Jan 1, 1999

By Koji Matsubara, Yoshiaki Iguchi, Shoji Hayashi

Iron ore particles of a limonite iron ore were reduced completely with H2 at 1023K to 1273K in a fluidized bed. Then, at 973K, the formed iron was exposed to HrH2S mixtures (sulfur activity, as=0.5) for 3.6ks and carbidized with CO-H2-H2S· mixtures at 0.1 MPa. During the carbidization, the particles of about 150mg were sampled at every 600s interval. The sampled particles were analyzed by XRD and chemical analysis for C and S to evaluate the content of Fe3C, Fe5C2, Fe and free carbon. The reaction extent is defined as fo=Xfc3C +xFc5c2; x is the molar fraction of Fe in Fe3C. The carbidization curves can be fitted very well to -ln(l-f0)=g(pb T)t; g(p; T) is the carbidization rate, i.e. the carburization rate on the pore surface of reduced iron. The rate is found to be nearly proportional to the specific surface area of reduced iron, a P 0 , which decreases with increasing the reduction temperature. The value of a P 0 does not change by the carbidization and the stability of the iron carbide product in the atmosphere increases with the temperature.

Jan 1, 2000

By Ana Carolina dos Reis Lima

Este artigo tem o objetivo de apresentar a capacidade de remoção de íons Pb2+ de um argilomineral oriundo da região sudoeste do Pará. A caracterização do argilomineral foi feita através das técnicas de Difração de Raios-X (DRX) e Microscopia Eletrônica de Varredura (MEV). A metodologia utilizada foi a do sistema de banho finito para determinação da percentagem de remoção (%Rem) do argilomineral. Foram utilizadas três concentrações sintéticas de chumbo (10, 30 e 50ppm) com diferentes pH (3, 4 e 5) para avaliação da absorção de íons pelo argilomineral. Ainda, este argilomineral foi revestido com quitosana com previsão de aumentar a adsorção dos íons Pb2+. Os resultados mostraram o potencial de adsorção acima de 95% para todas as concentrações em pH 5; e a adição de quitosana aumentou esse potencial para acima de 99%. Em pH 4, a, a quitosana proporcionou aumento na percentagem de remoção na concentração de 10ppm. Isso implica em uma potencial aplicação para remoção de metais pesados em efluentes da região sudoeste do Pará em vista da extração de minério presente nesta região.

Oct 30, 2017

By Jeannine Wendy Salas Huamán

Dado que la empresa minera tiene como objetivo el fortalecimiento de la responsabilidad social y ambiental para la AID (Puno), se implementa un programa de actividades que responda a la responsabilidad social y ambiental. En ese sentido, el presente texto describe la capacitación como una herramienta de una logística -en tanto se entrene a los pobladores de la AID para que puedan brindar servicios a la minera, se concilie la explotación minera con la población mediante la logística y se establezca una alianza con los pobladores formándolos como proveedores, de forma que se obtenga una ganancia conjunta.

Nov 1, 2013

By Carolina Sartori Marzullo

Apresenta-se a metodologia e sistemática para gestão da capacitação como ferramenta para aumento da competitividade e ganho de resultados do negócio num contexto crítico para o segmento.

Aug 16, 2017

By S. R. S. Sastri

By using the data of E.A. Hersam and F.C. Bond's equation for energy consumption in comminution, a method was developed to analyze the performance of industrial jaw crushers. The study showed that industrial jaw crushers are generally operated below capacity. The study also showed that industrial jaw crushers generally have sufficient installed power to operate at, full capacity. The method presented can be used to estimate the capacities and power requirements of jaw crushers.

Jan 1, 1995

By T. Kerr, C. Mattich, J. Wilson

"In refractory gold concentrates, gold is occluded in sulphide minerals preventing efficient cyanide leaching. Hence, roasting is used to oxidize sulphur and organic carbon, the latter being necessary to minimize recovery loss through the preg-robbing effect. In 2009, Outotec commissioned the circulating fluidized bed roaster at Syama gold mine in Mali. Since 2013 Resolute and Outotec have been implementing improvements to the roaster performance with the capacity increasing from 8000 t/month in 2013 to above 13,000 t/month in 2016, while achieving a residual sulphide sulphur and organic carbon contents of below 0.1 wt.% and 0.4 wt.%, respectively. Thus a gold recovery in the CIL of above 90% is attained. In 2016, Outotec audited the Syama roaster. The analysis resulted in the Low Carbon Roaster (LCR) upgrade concept which (i) allows re-processing of calcine dust from the spray cooler and ESP after pelletization and (ii) allows the roasting of a further fine-organic carbon rich feed, i.e. de-slime circuit tailings. The LCR upgrade aims to reduce organic carbon to <0.2 wt.% and increase roaster-leaching gold recovery by >3%. Project development included extensive testwork. The LCR process is expected to become operational during FY 2019.INTRODUCTION Double refractory sulphide ores exhibit the characteristics of gold locked within pyrite grains, in the presence of preg-robbing natural (organic) carbon. Hence, to achieve high recovery during subsequent processing steps, i.e. cyanide leaching, oxidation of sulphide sulphur is required, producing a porous calcine by way of a roasting step. This allows for the gold contained within the pyrite grains to be accessible during cyanide leaching. Furthermore, it is necessary to oxidize the organic carbon. Oxidizing the organic carbon is essential as gold recovery loss occurs as a result of gold-cyanide complexes being adsorbed on organic carbon, this phenomenon is termed as preg-robbing (Miller et al., 2016). The gold absorbed on the organic carbon is lost, reporting to the tailings stream. Hence, the aforementioned oxidation of sulphide sulphur and organic carbon is the process goal. Nonetheless, the latter must occur at a controlled temperature which is concentrate/ ore specific, since the pores of the produced calcine should not sinter, as this makes the gold contained in the calcine less accessible during leaching, leading to gold recovery loss. The tight temperature control requirement is a decisive factor in the choice of a Circulating Fluidized Bed (CFB) as the roasting reactor, due to the excellent mixing characteristics of the CFB which results in temperature homogeneity of (+/-10°C). Roasting of double refractory ores, as described above, can be included in the flowsheet after comminution and grinding, a process termed as whole ore roasting, or by including a flotation circuit termed as concentrate roasting. Roasting the flotation concentrate results in less solid flow, increased sulphide sulphur grade and organic carbon content resulting in a higher heating value and higher gold content. A typical composition of the Syama ore and concentrate is given in Table 1. Ore average values presented correspond to the period 2015, while concentrate values are typical for the flotation performance throughout the period 2012–2015."

Jan 1, 2017

By T. Krumins, F. C. Ruff, M. Eichhorn, L. Zunti

Hatch Ltd. has recently completed a project to increase refractory gold ore processing capacity at Newmont Mining Corporation’s Twin Creeks facility. The objective of the project was to increase throughput by approximately 10% by adding a third autoclave feed pump to each of the two autoclave circuits. To minimize project capital cost, autoclave feed pumps from Newmont’s decommissioned Lone Tree facility were evaluated and found to be suitable for this new service. The existing pressure oxidation circuit was reviewed in a debottlenecking study to determine other upgrades required to facilitate the increased throughput. Interruption to operations was minimized with a detailed construction plan, supplemented with detailed 3D layout model sequencing studies. The focus of this paper is project development, multi-discipline design considerations, and implementation results.

Jan 1, 2014

By N Steenkamp, L Furstenberg, W Cele, M Richter

Managing productivity and improving efficiency for a healthy return on capital employed have become key mining industry strategies under prevailing tough global market conditions. However, achieving this in a multisystem environment such as a mining operation can be daunting. The field of discrete event simulation offers some relief, giving engineering teams insight into multivariable systems and stochastic processes. It allows for integrated system thinking and domain expertise to be woven into project thinking fibre. Directed system optimisation and therefore improved efficiency becomes possible. Furthermore, capital discipline accrues from optimal upgrade investments. This paper illustrates the practical application of this approach by reviewing a typical case study for a direct shipping iron ore operation. Dynamic simulation was used to establish maximum processing plant capacity under varying material characteristics and identify capital-efficient upgrades for increasing production.The study started with descriptive statistical analysis of existing data. Discrete equipment and system capacities were defined, followed by static plant mass balance calculations to establish bottlenecks and overall static capacity. Equipment ‘uptime’ and ‘downtime’ analyses established system and overall plant availability and utilisation. From this information, a dynamic simulation model could then be developed and initially calibrated against actual plant performance to verify its robustness. Once confirmed to accurately represent existing plant dynamics, system capacity response to variable changes could be tested to ultimately determine maximum plant capacity. Additionally, plant optimisation was incorporated to arrive at optimal upgrade points. Maximum capacity and necessary upgrades were established as a function primarily of feed size distribution. Additionally, the interfacing effects of rehandling feed material to the final product grade and potentially to life-of-mine were established as important outcomes. The results of the study illustrate the value of using dynamic simulation models to realistically and cost-effectively increase throughput.CITATION:Cele, W, Furstenberg, L, Richter, M and Steenkamp, N, 2015. Capacity evaluation of iron ore processing facilities utilising dynamic simulations, in Proceedings Iron Ore 2015, pp 597–604 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By A. J. S. Benade, A. J. A. Heyns, N. B. Strydom

The maximum oxygen intakes of samples of about 30 Bantu, weighing less than 50 kg from different tribal groups (Zulu, Xhosa, Sotho and Shangaan) were measured on a treadmill. The mean maximum oxygen intake of the 164 men was 2,12 litresjmin and only 18 men (11 per cent of the sample) had maximum oxygen intakes of 2,5 litres/min or above (the minimum requirement for such tasks as shovelling rocks and tramming it). The samples of the different tribes differ in age, but when the age effect is taken into account then there were no significant differences between tribes in maximum oxygen intakes. An incidental finding was that both age and body weight correlated significantly with the maximum oxygen intakes of these underweight subjects. Not one of the subjects who weighed less than 45 kg or who was older than 40 years had maximum oxygen intakes high enough to permit their being able to do strenuous work underground. It is clear therefore that Bantu who weigh less than 45 kg or are older than 40 years should not be employed on such strenuous tasks as shovelling rock and tramming it.

By Stig Premfors

Lamco Joint Venture is operating a Dravo Pelletizing machine to produce pellets from the natural slimes of an earthy hematite ore. The grate area of the machine 3.3 x 106 m equal to 350 m2 (3800 sq. ft.) and the installed fan capacity is 8200 HP. The limiting factor for production is normally fan capacity. This means that the processing fans can not pull the additional air (i.e the additional calories or BTUs) through the bed which would be required for increased production. A way to increase production without major modifications is to supply the additional calories needed for increase production by adding coal to the pellet feed. After successful laboratory tests following method of coal addition has been chosen and the following results have been obtained. 1. The ground coal is added to the slurry prior to the filters and the rotary dryer. 2. By adding 0.6% coal, an increase of about 15% in production rate has been obtained. 3. No significant changes of metallurgical properties have been observed (i.e. tumbler index, compressive strength, ferrous iron content, reducibility, Linder degradation and swelling). 4. No unexpected operation problems have been experienced. The pellet discharge temperature increases and is the limit for how much production can be increased by coal addition without making plant modifications.

Jan 1, 1971

Mining of copper ore is still the most important business in Chile. In order to mine ore with a copper content of less than one percent at Minera Los Pelambres in an economical way, opencast mining is mandatory. Due to the prevalence of avalanches at the mine, the concentrator was located in a stable area, some distance from the mine. As a consequence, the material has to be transported between mine and concentrator by conveyor. A downhill conveyor system has been implemented for more than ten years as the most suitable and most economical ore transport alternative. Due to the length (12.6 km) and inclination (1300 m drop) of the conveyor system, the stresses in the steel cord belt are the dominant design criterion, resulting in a belt quality of ST 7800. Additional dynamic belt stresses during transient operating conditions are avoided by the installation of high capacity adjustable frequency drives. The rating of a single drive unit is 2500 kW. During ten years of operation, several capacity increases have been implemented, from an initial 5800 t/h up to the current capacity of 9900 t/h. This presentation describes the engineering challenges of the implementation of the world&apos;s strongest belt conveyor system. Capacity increase measures like the development of new control and breaking strategy, proved by dynamic simulation of belt forces and belt speed scenarios are explained. During this long-term partnership of RWE Power International, the former Rheinbraun Engineering, with Minera Los Pelambres, RWE has been engaged continuously for development work, safety checks, expert opinions and maintenance audits, and giving new impulse to conveyor technology.

May 1, 2010

By S. Sarioglan

The bleaching of edible oils, industrial oils, and some chemicals may be achieved using natural and acid-activated clays. These materials remove impurities and pigments from the oils. In this work, a bentonite clay from Turkey (Somas bentonite) was activated with different concentration of H2SO4 and HCl at 70~90°C and 5~8 hours. Under these conditions several cations were removed from natural bentonite (Al, Mg, and Fe) and DTA-TGA, FT-IR curves of the solids obtained after acid treatment were examined. Treatment time and acid concentration increased the degree of destruction of the bentonite structure which was determined by ICP. Activated samples were tested in order to verify their capacity to bleach soybean oil and compared to standard commercial bleaching clays. The experimental results indicate that treated samples with H2SO4 have the same efficient in bleaching crude soybean oil with the standards and treated sample with HCl is more efficient in bleaching than the commercial products.

Jan 1, 2014