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By Zihe Ren, Edouard Asselin, Marcus Tomlinson, Tianbi Zhang, Jing Liu

"Raman spectroscopy is used to quantify the extent of disorder in the carbonaceous matter associated with preg-robbing ores. Previous studies of Goldstrike ores showed that the height and width of the peaks for the “D” (disordered) and “G” (graphite) bands, the so-called “Raman ratio” had a strong correlation to the preg-robbing value (PRV) measured for various ore samples. A brief literature review on Raman spectroscopy as it applies to preg-robbing ores is presented. Further, recent studies, presented here, have shown no correlation between the Raman ratio and the PRV for a wide variety of ores. This suggests that the extent of organic carbon crystal disorder is not the main factor in determining preg-robbing characteristics.INTRODUCTION Preg-robbing may arise from natural carbonaceous materials in the ore. Several mechanisms have been proposed in the past decades including a physical sorption process by the carbonaceous matter, or via the reduction of aurocyanide at the mineral surface (Abotsi & Osseoasare, 1986; Afenya, Osseoasare, & Abotsi, 1983; Tan, Feng, Lukey, & Van Deventer, 2005). Nevertheless, the mechanisms of preg-robbing remain poorly understood. Understanding the nature of the preg-robber is of practical importance for the selection of a suitable treatment process. Fine carbon particles in the ore have been recognized as preg-robbers due to their similarity to the activated carbon used in the carbon in leach (CIL) or carbon in pulp (CIP) processes. Previous research has illustrated that the activated carbon (also referred to as amorphous carbon in some literature) has a much higher absorption ability than pure graphite with high crystallinity (Adams & Burger, 1998). Adams et al (Adams, Swaney, Friedl & Wagner 1996) concluded that carbonaceous matter is largely responsible for the overall preg-robbing capacity of a given ore. However, the mechanism of carbon preg-robbing was still not clear mostly due to the complexity of amorphous carbon and its behavior in different solution matrices, and at different pH and temperature (Adams, 1990, 1993)."

Jan 1, 2017

By A. L. de Vegt

For the past ten years Paques has been engaged in the development and installation of treatment systems based on biotechnological processes to remove sulfur compounds from water, air and gaseous streams. Metal and sulfate can be removed from mine waters using two biological steps: 1. Sulfate reducing bacteria convert sulfate to hydrogen sulfide (H2S). The H2S reacts with the dissolved metals to form insoluble metal sulfide precipitates. 2. Sulfide oxidizing bacteria convert excess H2S to elemental sulfur. Paques has designed and installed a groundwater treatment system for the Budelco zinc refinery in the Netherlands to remove metals and sulfate as described above. The system has been operating since May 1992 treating a flow of 5000 m /d. A pilot plant started operation in November 1995 at Kennecott's Bingham Canyon Utah copper mine to develop the processes for metal and sulfate removal from groundwater and selective copper recovery from leach water. The principle of the biotechnological methods, full scale experience, and an overview of the test program at the copper mine are presented.

Jan 1, 1997

By X. Shi, V. Vallyathan, N. S. Dalai

"Using. ESR spin trapping methodology, evidence was obtained that fresh quartz dust in a cell-free aqueous medium generated hydroxyl - and possibly superoxide radicals. The hydroxyl radical generation potential decreases on storing of fresh quartz dust in ambient air and on the addition of either catalase, superoxide dismutase, desferoxamine, or DMSO. The role of quartz related radicals in the biochemical mechanism of acute silicosis is suggested from these findings.IntroductionThis report summarizes our electron spin resonance (ESR) detection of oxygenated radical formation by freshly crushed quartz particles in a cell-free aqueous medium, and its inihibition by radical scavengers. This study was undertaken with to elucidate the primary biochemical mechanism involved in the development of silicosis (Farber, 1983; Reiser and Last, 1979; Silicosis and Silicate Disease Committee, 1988). In particular the mechanism by which the quartz particles exert their toxic action on cells and the process(es) by which these actions progress to fibrogenesis are still not well understood (Farber. 1983; Reiser and Last, 1979;). It is generally believed that the action of quartz particles on the cell membrane is the starting point of the silicotic process (Farber, 1983; Parazzi et al., 1968). Thus the surface characteristics of the quartz particles have been the subject of several recent studies (Bolls et al.. 1983; Dalai et al., 1986; Fubini et al., 1987). Recently, We reported that mechanical crushing of quartz under normal atmosphere generates free radicals which decay with time, and that these free radicals are associated with a higher cytotoxicity of fresh quartz dust as compared to aged dust from the same stock (Dalai et al., 1986; Vallyathan et al.. 1988). The formation of Si• and. SiO--type of radicals from quartz particles crushed under atmospheric conditions has also been reported by Fubini et al. (1987). In addition, Gulumian and van Wyk (1987) have reported that quartz particles react with hydrogen peroxide (H202) to generates hydroxyl radicals (•OH) and suggested that this process might contribute to quartz's pathogenicity. However, these authors did not report the effects of metal chelators, so it was not clear as to whether the detected -OH radicals simply resulted from the Fenton reaction involving exogenous metal ion contaminants. Earlier, Marasas and Harington (1960) reported that quartz particles could function as an oxidant in a number of in vitro oxidations, including the hydroxylation of proline and lysine. They postulated that silica dusts, on reacting with water, could release H2O2 which might have the potential to react with various biological constituents and thus cause tissue damage. In fact, Gabor and coworkers (Gabor and Anca, 1974; Gabor et al., 1975) suggested that the cytotoxicity of quartz particles might be associated with the generation of some 'factor or factors possessing the properties of a free radicals capable of promoting the peroxidative chain cleavage of polyunsaturated fatty acid moieties of the phospholipids in the cell membrane. More recently Weitzman and Graceffa (1984) reported that asbestos is able to catalyze the generation of • OH radicals from H2O2. Their later work indicated that lipid peroxidation may be one of the mechanism by which asbestos produces tissue injury (Weitzman and Weitberg, 1985). This is significant because • OH radicals are capable of causing peroxidation by abstracting hydrogen atoms from cell-membrane lipids and initiating lipid peroxidation in lysosomal membrane (Fong et al., 1973). In fact, the formation of oxygenated species in reactions involving quartz was suspected since Kolbanev et al. (1980) reported the detection of H2O2 in the reaction of fresh quartz particle with aqueous medium. The present work was thus undertaken to detect the anticipated formation of some oxygenated, radical species by reactions of quartz in a cell-free media and its inhibition by radical"

Jan 1, 1988

By S Bhandari

This paper is a step in the direction of developing a computer model of the near source dispersal of suspended particulate matter (SPM) in planetary boundary layer (PBL). Since Surface Mine blasting is done during daytime, study of daytime dispersion in convective boundary layer (CBL) is relevant to the mining engineers. The scope of this paper covers dispersal after the blast in any type of PBL ie stable, convective and neutral but only under weak wind condition. Mathematical analysis of the dispersion of vertical dust column has been carried out during weak wind conditions in a tropical meteorological environment. It is noted that dust concentration reaches its maximum value some distance away from the point of blast, immediately after the blast (t*=1) and thereafter rapidly decreases. After a short interval from the time of blast at t*=11 the dust concentration shows linear decrease in concentration with distance. Dust concentration also rapidly drops during the interval t*=1 to t*=11, thereafter, rate of drop is nearly the same at any distance from the point of blast.

Jan 1, 2001

By Z. Abbasloo, A. Masoomi, L. Ebrahimi, A. Mortazavi, A. Keshavarz

"Investigation and 3D analysis of Heap no. 2 of Meydook copper complex was the subject of this study. In this project all geological and geotechnical investigations conducted in the mine were evaluated aiming at determination of Heap no. 2 design parameters. The main objective of the project was to evaluate the potential for construction of Heap. No. 2 on a waste dump built in a valley in the north side of the pit.Considering the space limitation for dump location this was a viable alternative to reduce the costs associated with heap no. 2 construction. Moreover, it allowed for a significant reduction in overall mining costs. Considering the project condition, a 3D analysis of heap major structures including; valley rock foundation, waste dump, and low grade ore was carried out. Five sets of analyses were conducted and the displacement and stress fields were calculated within the heap no. 2 components. In all analyses conducted the subsident profile was determined for the valley base rock and heap foundation (waste dump). Moreover, the shear interaction between heap and waste dump was evaluated at the heap interface. The analyses results showed that the maximum settlement at the heap base is about 4-5 cm and the waste dump provides a safe and reliable base for heap construction. Moreover, the analysis results showed that the selected %5 grade for the heap interface is good and does not pose any risk in terms of heap Interface shear displacements. A sensitivity analysis of heap mechanical parameters was also conducted. The obtained results show that if the friction angle of heap material is reduced below 25 degree due to acid spraying process, the heap walls become unstable and the heap geometry must be redesigned."

Jan 1, 2015

By S. A. Luciani

"In 1957, an asbestos orebody was discovered in the northern sector of the Ungava Peninsula of the Province of Quebec, an area now identified as Asbestos Hill. The deposit is situated on a plateau 1700 feet above sea level and 42 miles inland from Hudson Strait. It is a bleak, iso. lated location of typical arctic environment. Fifteen years were to pass before the first shipment of ungraded fibre was made in 1972. These years we1•e occupied with field surveys and investigations, diamond drilling, engineering design, evaluation of investment and operating costs, and construction. The problems normally associated with mine development were further complicated by location, isolation, and the extreme cold and permanently frozen ground of the arctic regions. Unique to an isolated arctic operation are the organization of support facilities and services, procurement and retention of personnel, construction of access roads and airports, and scheduling of product out and supplies in during the short summer period of sea navigation."

Jan 1, 1976

By R. Reeves

Coal producers and utilities depend on automated coal blending systems to reduce costs and meet stringent environmental regulations. Over 30 systems installed in the United States since 1987 use on-line PGNAA (Prompt Gamma Neutron Activation Analysis) analyzers to accurately control the blending process. Experience and detailed engineering are required to integrate real-time data produced by the coal analyzer with a control system to meet demanding performance specifications. This article reviews successful installations and lists important features including interfacing analyzers with plant control systems, specifying feeders and weigh scales, and managing data.

Jan 1, 1995

By Andre L. De Vegt

For the past eight years Paques has been engaged in the development and installation of treatment systems based on biotechnological processes to remove sulfur compounds from water, air and gaseous streams. Metal and sulfate can be removed from mine waters using two biological steps: 1. Sulfate reducing bacteria convert sulfate to hydrogen sulfide (HzS). The HzS reacts with the dissolved metals to form insoluble metal sulfide precipitates. 2. Sulfide oxidizing bacteria convert excess H2S to elemental sulfur. Paques has designed and installed a groundwater treatment system for the Budelco zinc refinery in the Netherlands to remove metals and sulfate as described above. The system has been operating since May 1992 treating a flow of 5000 m3/d. A test program, utilizing a large scale pilot plant, will commence in November 1995 at a copper mine in the U.S.A. to remediate groundwater contaminated with sulfate and heavy metals. Biological reactor performance and selective metal recovery will be studied. Sulfur dioxide (S00 can be removed from fluegas using a combination of scrubber technology and the two biological steps. The end product is elemental sulfur. A commercial size biological desulfurization plant has been in operation since July 1994 treating 50,000 Nm3/h of fluegas. Sulfide can be removed from mining waters or anaerobic wetlands using a THIOPAQ® Sulfide Oxidizing reactor.

Jan 1, 1996

It is well known that the crushing and grinding steps in the mineral processing of ores represent a substantial proportion of total energy, cost and carbon emission in mining. For instance a recent study calculated that 36% of the energy consumed by gold and copper producing mines in Australia was attributable to comminution (Ballantyne et al, 2012). Understanding this component of a business is essential in a world seeking to lower production costs, improve earnings and reduce its carbon footprint. The issue commands the attention and support of industry leaders in the mining sector, government, equipment manufacture, engineering design and research organizations. Furthermore, several researchers have often stated that globally, comminution processes consume between 3-4% of the world?s electrical energy production (Daniel and Lewis-Gray, 2011). In 2009-10, Australia?s Federal Government Energy Efficiency Opportunity (EEO) participants in the mining sector used 336.5 PJ, representing approximately 6 percent of Australia's total energy use. It is evident that the current practices of breaking rocks in tumbling mills are relatively inefficient (Fuerstenau and Abouzeid, 2002). Research and improved engineering design has established that a range of improved blasting, crushing and grinding techniques and flow sheets may lower project costs and carbon footprint. These include relatively simple process flow sheet strategies such as gangue rejection or pre-concentration prior to size reduction, a better combination of grinding technologies (both current and new systems), and selection of coarser grind sizes where ore and waste mineralogy allow. Yet, despite this systematic and detailed research, the industry remains somewhat reluctant to implement these strategies. CEEC (Coalition for Eco-Efficient Comminution) was established in 2011 to support knowledge sharing and change in an area of high-energy consumption for the global mineral industry. CEEC is a not-for-profit industry company, funded by grants from world wide industry companies, whose mission is to accelerate knowledge and technology transfer in the field of energy-efficient comminution. The key benefit to the mining sector arising from CEEC?s activities will be an increase in the rate at which more energy-efficient comminution data sets, processes, and technologies are developed, demonstrated, shared and applied. This will contribute directly to the industry?s target of reducing operating costs and carbon emissions. CEEC International Ltd and JKTech Pty Ltd teamed together to facilitate the inaugural CEEC Workshop, in June 2012. The purpose of the workshop was to produce a roadmap to provide guidelines for how (1) operations can achieve best EEC practice in the short to medium term, in collaboration with vendors, engineering companies and other service providers, and (2) what R&D is needed to achieve paradigm change in EEC in the medium to long term, e.g. 75% reduction in comminution energy in 10 years.

Sep 1, 2012

By M. G. Mena, M. S. Mena-Junio

Silver (Ag) filler is the most attractive choice among all the conductive fillers of die attach materials for the attachment of silicon devices because of its balanced properties and relatively low cost. However, a major problem of silver is that it electrochemically migrates in the presence of moisture and applied bias. In microelectronic devices, silver migration can occur between adjacent conductors/electrodes, which leads to the formation of dendrites and eventually results in short-circuit failure. In order to assess the reliability of these conductive fillers, an investigation for two types of Agfilled die attach materials was done using the water drop test at room temperature and using a 1000 hour temperature-humidity-bias (THB) test under 85 ºC and 85% RH conditions. Four different bias/voltages and six different electrode distance spacing were used. Both dendrite and cloud/lace-like growths were observed as a result of the electrochemical migration of silver, Water drop test results revealed that increasing the applied bias/voltage and decreasing electrode spacing causes migration to occur faster, thus resulting into shorter time to fail (TTF). It was also observed that the growth rate of the dendrites from the cathode increased linearly as the dendrite approached the anode, probably due to a combination of increased ion availability and electric field. A minimum applied bias of 3 volts was required for migration to occur in Epoxy A as compared to 2 volts for Epoxy C. The higher migration voltage requirement for Epoxy A was attributed to the higher volume resistivity of the said epoxy. In addition to the minimum voltage requirement, it was observed that a minimum electric field of about 1 volt/mm is required for migration to occur. The 1000 hour THB testing did not result into any failures. It is surmised that the presence of condensed moisture is another requirement for migration. Such condition is not present during the THB testing.

Jan 1, 2012

By B. J. Jody

At Argonne National Laboratory, we have been developing a potentially economical process to recycle automobile shredder residue (ASR). We identified three potentially marketable materials that can be recovered from ASR and developed technologies to recover and upgrade these materials. We built and tested a field-demonstration plant for recycling polyurethane foam and produced about 2,000 lb (907 kg) of recycled foam. Several 300-lb (I36-kg) samples were sent for evaluation and were found to be of marketable quality. We are also preparing for a large-scale test in which about 200 tons (181 tonnes) of ASR-derived fines «0.25 in. [<0.62 cm]) will be used as a raw material in cement making. A major cement company has evaluated small samples of fines prepared in the laboratory and found that they meet its requirements as a substitute for iron ore or mill scale. We also produced about 50 lb (23 kg) of recycled acrylonitrile butadiene styrene (ABS) from obsolete automobiles and found that it has properties that could be readily upgraded to meet the specifications of the automotive industry. In this paper, we briefly discuss the process as a whole and summarize the results obtained from the field work on foam and fines recycling.

Jan 1, 1996

By Onur Guvener, Kalaiarasi Vembu, C. Vipulanandan

"Installation procedure and the quality of the material used in the construction have significant effects on the behavior of the Auger Cast in Place (ACIP) piles. In this study, Installation and curing of a 760 mm (30 in.) diameter and 12 m (39 ft) long ACIP pile with a design capacity of 1140 kN (128 tons) in hard clay was investigated. Construction quality was monitored using the automated monitoring system where the volume of grout pumped and the pressures were monitored with depth. The curing of the pile was monitored using axial vibrating wire strain gages at four levels and lateral vibrating wire strain gages at two levels. The residual strain and temperature profile in the curing pile was monitored over a period of week to determine the appropriate time for load testing the pile. Axial behavior of Auger Cast in Place (ACIP) Piles in hard clay was studied using full scale load test on an instrumented pile. The load-settlement and load transfer relationships of the pile was investigated based on the load test results. Development of skin friction in the load test pile and the reaction pile was also investigated.INTRODUCTIONAugered cast-in-place piles (ACIP) are drilled foundation installed by drilling a hole with a continuous flight auger to a predetermined depth. Non-displacement Augered Cast-in-Place (ACIP) piles are increasingly used for supporting building, bridges, sound barrier walls and many other structures around the world. In an ACIP pile, depending on the soil type and rate of the auger advance, ground stresses are maintained near the value that existed before construction by using a continuous flight auger, which is never withdrawn until the cementitious material (fluid Portland cement grout) is placed by pumping the grout beneath the withdrawing auger under pressure through the hollow stem of the auger (Vipulanandan, 2005). ACIP piles are typically installed with diameters ranging from 0.3 to 1.0 m and lengths up to 30 m (Brown, 2005) although longer lengths have occasionally been installed. Comparing to the drilled shafts and driven piles of equivalent size ACIP piles can be installed more rapidly with fewer disturbances to the surroundings in favorable geological conditions. Hence the installation procedure and the quality of material used in the construction have significant effects on the behavior of ACIP piles (Vipulanandan, et al. 2007). In this paper construction quality control technique for ACIP piles was investigated. Load displacement and load transfer behavior of pile in compression and tension in hard clay was also studied. The development of side resistance in compression and tension for the load test piles and the reaction pile were also investigated."

Jan 1, 2017

By B. Courtaud, L. Donati, V. Weigel

As a growing mining company, ERAMET is looking for new positions in the strategic metals market. In this context, the Gabonese Maboumine pyrochlore deposit is currently being studied for the recovery of niobium, tantalum, rare earths and uranium. This ore shows mineralogical and chemical characteristics that make it challenging to process by existing practices, from both technical and economic points of view. ERAMET has developed since 2008 an innovative hydrometallurgical process, which has been successfully operated at a pilot plant scale (more than 35 weeks in continuous). The upstream part of the process aims to dissolve valuable elements in sulphuric acid. The first step is dedicated to dissolve the ore matrix, leaving the pyrochlore unleached. The second step consists in chemically breaking down pyrochlores in order to form soluble species of the valuable elements. After dissolution, the valuable elements are separated into different flows: niobium and tantalum are recovered and transformed as commercial ferroniobium on one side, and rare earths and uranium remain in the solution to be recovered in the downstream part of the process. The main goal of this paper is to discuss the upstream part of the process, which has given successful results.

Jan 1, 2014

By Shigetoyo Yasui, Masahiro Saitou, Nobushige Yasuoka, Keisuke Tsujimoto

"The Dry Jet Mixing (DJM) Method was developed and has been put to practical use on the initiative of the Public Works Research Institute and Japan Construction Method and Machinery Research Institute. This method is used to inject powdery binder with compressed air into soft ground while mixing the binder with the soil using the mixing blade to reduce the moisture content of the ground and cause chemical reactions between the soil and binder, thereby strengthening the ground and stabilizing its quality.Recently, there is a demand for high-quality, high-accuracy execution control.This paper introduces the New DJM Execution Control System, developed to meet the future demand for more sophisticated ground improvement, based on the past results of the conventional system in order to provide new automated execution control with improved accuracy, functionality and column quantity.1. INTRODUCTIONIn association with the densification of cities and the improvement of the social overhead capital, the underground space in urban areas is tangled with various underground structures including transportation facilities such as subways and underground roads, buried pipe such as water supply and sewerage systems,gas, electric power and communications lines, and underground malls.In addition, a lot of aboveground structures such as office and residential buildings, elevated tracks, expressways, embankment tracks are also supported with underground foundations.Tokyo, Osaka, Nagoya and many other large cities in Japan grow on plains spread along the coast or rivers. Waterfront flat areas which are very convenient for human activities, however, are often on the alluvial soft ground, where soft cohesive soil with a high moisture content, loose sandy soil, etc. are accumulated in a thick formation, with a high groundwater level.The DJM Method introduced here is used to decrease the moisture content of the soft ground, strengthen the ground and stabilize the soil quality by injecting powdery binder into the ground with compressed air, while mixing the binder with the soil using the mixing blade.2. OUTLINE OF DJM METHODThe DJM Method is used to inject powdery binder with compressed air into soft ground, while mixing the binder with the soil using the mixing blade, to cause chemical reactions between the soil and binder, thereby decreasing the moisture content of the ground and strengthen and stabilize the ground."

Jan 1, 2015

By Kiyotaka Ohno, Nobushige Yasuoka, Yosuke Hioki

"The diameter of improved columns adopted by the original DJM Method had been 1000 mm, however, in order to comply with the social need for construction cost reduction, the Expanded Dry Jet Mixing (EX-DJM) Method with maximum column diameter expanded to 1300 mm was developed between 1998 and 2001 and has been widely applied since then. From the first application of EX-DJM in January 2002 for a first construction project, the total volume of improved soil has reached 325,000 m3 in 17 projects up to September 2014. Because of the advantages of the EX-DJM such as reduction of construction costs and periods leading to reduction in the number of improved columns, adoption of this method is expected to increase in the future. This paper describes the advantages of the EX-DJM, its construction results and case examples including those applied to restoration projects after the Great East Japan Earthquake, 2011.1. BACKGROUND OF DEVELOPMENTThe Dry Jet Mixing (DJM) Method is a soil stabilization method in which a powdery or granular binder is pneumatically fed into and mixed with soft soil to induce chemical reactions that stabilize and strengthen the soil. It was developed by government - private collaboration in Japan between 1977 and 1979. Up to March 2014, the total volume of soil improved by DJM method reached 33,500,000 m3. The initial diameter of improved columns of the original DJM Method was 1000 mm. In order to comply with the social need for construction cost reduction, the Expanded Dry Jet Mixing (EX-DJM) Method with maximum column diameter 1300 mm was developed between 1998 and 2001.2. ADVANTAGES OF EX-DJMThe construction equipment for the EX-DJM consists of two major parts, which are DJM machine and binder plant are shown in Fig. 1.The construction machine is of double mixing-shaft type with its column diameter expanded to 1200mm or 1300mm. In association with the increase in the column diameter, the binder feeder has also increased its discharge rate by approximately 1.69 times. Same as the increase rate of the area of original diameter 1000mm to diameter 1300mm are shown in Fig. 4."

Jan 1, 2015

By Jay A. Carpenter

IN six years the construction of Hoover Dam and the power plants probably will have reached the operating stage and this vast new source of power will then be continuously available for industry. The height of the darn will be 580 ft. and the average annual flow of the Colorado River is calculated at approximately 24,000 cu.ft. per sec. If this full head and average flow can be maintained the year round, about one million horsepower will be generated. The U. S. Reclamation engineers, taking into consideration the probable range in flow and head, have set the figure for power contracts at 660,000 firm horsepower, which can be assured at all times of the year. During the months of heavy run-off of water from the Colorado River Basin the power plants should be able to generate the full 1,000,000 hp. capacity of the power plants, so there will be 340,000 excess or secondary horsepower. The cost of firm power at the switchboard will be close to 2.15 mills per kw.-hr., equal to $14.05 per hp.-yr., and the cost of the secondary or off-peak power will be close to 0.8 mills per kw.-hr., or $5.22 per hp.-yr. In no place in the country can such cheap power be obtained today. The electrochemical industry is in a state of flux because the power costs from its old sources have increased so much (to $30 per hp.-yr. at Niagara) that the industries have had to seek new sources, so they have gone to Canada and Norway and built new plants.

Jan 1, 1932

By Sunil Katharia

In February 2016, the upgraded Blast Furnace 1 of JSW Steel Limited (JSW) at its Vijayanagar Steel Plant was blown in after a 6 months shutdown in which the whole furnace was rebuilt on the existing foundation and within the existing tower structure. Despite several plant constraints it was possible to increase the furnace inner volume by 85% - reaching 2307 m3 from existing 1250m3. The upgradation project covered the stockhouse and its dedusting system, top charging system, furnace profile, furnace cooling system, casthouse and its dedusting system, slag granulation plant, pulverized coal injection plant, hot blast system and gas cleaning plant – with major interventions in order to cope up with the changed operating conditions. The total scope of the project was split by JSW into several packages, all based on design data provided by Paul Wurth. JSW was responsible for coordinating the local subcontractors along with Paul Wurth which has been appointed as main technology supplier in charge of complete basic and selected detail engineering in the key areas and of the supply of core equipment such as the Bell-less Top®, copper staves, GCP key items and TMT casthouse machines. The main design concept and the key points of the project such as optimization of project ROI, advanced erection concepts as well as a summary of the operating results are presented confirming JSW “BF1” upgradation as one latest examples of the current state of the art in the revamping projects.

Aug 17, 2017

By CRO CRO

Elk Valley Coal?s Cheviot Project is located in the Alberta foothills south of the town of Hinton. The mine has been in operation now for the 3 years. The start up and subsequent operation of the Cheviot project has been directly influenced by the Cardinal River Mine. As the Cardinal River Mine was winding down due to reserve depletion in 2004, the price of seaborne traded metallurgical coal jumped to record levels and customers began aggressively seeking new sources of supply. Several months later, the owners of Elk Valley Coal decided to begin mining at the Cheviot mining area, extending the life of the area?s operations by over 25 years. The Cheviot Project had been delayed by low coal prices, ownership changes and a complicated and lengthy regulatory process fueled in large measure by stiff opposition from a number of major environmental organizations. Chief to the startup of the project was the construction of a 23-kilometer-long haul road that would connect the new coal measures to the existing Cardinal River processing and rail facilities. Construction of this road was completed with the first coal truck making its first trip in October 2004. This paper will look at some of original assumptions, the actual mining experiences and the lessons that were learned while moving from the drawing board to the current development as it exists today.

May 1, 2007

By S. Green, R. Yang

Blasting is a commonly used method for rock fragmentation in mining operations for mineral extraction. It involves breaking the rock mass into small pieces, and ideally creating micro fractures within the small pieces. Such micro fractures could significantly reduce the energy required for subsequent processes like crushing and comminution. Additionally, micro fractures would enhance the rock-fragraments fluid permeability thereby enhancing desired chemical reactions during certain processing operations. This paper presents recent developments of the Multiple Blasthole Fragmentation (MBF) model, which simulates blasting rockmass fragmentation. The MBF model allows estimating rock strains experienced during the blast, for various blast design parameters and geometries. The intent is to correlate these strains with created micro fractures in the blast rock fragments. Adjusting blast design parameters in the MBF model of explosive loading and delay timing allows blast optimization. Such optimizing would create desirable strains to enhance micro fractures within the rock fragments. This would improve mining operations by enhancing downstream operation efficiency, thus reducing costs.

Jan 1, 2024

By Patrick J. Hannigan, Seth Robertson, Frank Rausche, Rozbeh B. Moghaddam

The Top-Loaded Bi-Directional Test (“TLBT”) and the conventional Bi-Directional Load Test (“BDLT”) are full-scale load tests where loads are applied bi-directionally to the foundation element. The BDLT uses an embedded loading source consisting of a jack assembly with one or multiple hydraulic jacks located between two steel bearing plates. As the jack(s) within the jack assembly is/are pressurized, the plates receive the load from the jack(s) and transfer these loads to the foundation element. In the case of the TLBT, the loads are also applied bi-directionally to the foundation element. However, in the TLBT case, the loading source is located above the foundation head. With the TLBT’s non-embedded and reusable load assembly, the loads are applied to the foundation using the steel shaft bearing and base bearing plates cast within the foundation. These plates are connected to the load assembly at the foundation head via Grade 75 or Grade 150, threaded, steel bars. This paper presents comparison results from a full-scale load test performed by both bi-directional load testing methods on adjacent test shafts. Details regarding subsurface conditions as well as test shaft construction and installation are included for the comparison tests. Test results and corresponding analyses are presented and discussed in detail.

Sep 8, 2021