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By Sanjay Kumar Singh

This paper presents ground control technology associated with a continuous mining operation for mass exploitation of underground coal deposits in the Indian coal mining Industry It shows that competency of roof strata and performances of continuous miners are safer, than other coal mining method as well as productive and economical. Continuous miners keep playing a major role in the underground coal mining industry for their safety and as well as their productivity. Regarding past experiences in Indian coalfields, Chirimiri and Jhanjara mines have achieved exceptional performances, with a potential for over 500,000 tonnes per year. Tandsi mine has difficult roof conditions and does not typically achieve high production and productivity. Even so, the difficult roof conditions have been controlled with modern ?world best practice? roof bolting systems and an output of up to 1,200 tonnes per day has been achieved. It can further be emphasized that if this technology is implemented properly it will bring an unfathomable change to the Indian mining scenario. There are many mines in India that may have potential and economic viability with ground control technology concepts for installing continuous miner systems and beginning mass exploitation of underground coal deposits.

Jan 1, 2011

By Leonardo Massone

The p-y method is one of the most popular methods in pile design and has been calibrated for various boundary conditions using numerical and experimental studies during recent years. Most studies on reinforced concrete (RC) piles have included the impact of flexural nonlinearity, (e.g. nonlinear moment?curvature relations) but not considered associated pile shear deformations when deriving p-y curves from field data. Common p-y curves may be better applicable for piles with flexure dominated failures (e.g. piles with free- head boundary conditions). For piles with fixed head boundaries (i.e. rotation restrained piles) shear deformations could be of significant influence. To study this problem, a coupled shear flexure interaction model for axial-bending-shear behavior coded in OpenSees is applied to a 0.61 m flagpole and a 0.61m fixed head pile specimen to investigate the possible influence of shear deformations to the overall pile responses. The surrounding soil is represented by p-y curves derived from prior large scale testing on piles with similar boundary conditions. Analysis results show that for flagpole piles, shear forces and shear deformations were insignificant. Considerable contributions of pile shear displacements and forces were observed for the fixed head pile, with shear displacements contributing up to 40% of the total pile displacement. Results suggest that nonlinear shear deformations for reinforced concrete piles should be considered for fixed-head or similar conditions, and that currently used p-y curves may underestimate the actual lateral pile displacement and possibly lead to unsafe design for the particular boundary condition.

Jan 1, 2011

The schlieren technique describes an optical analysis method designed to enhance light distortions caused by air movement. The ability to visualize air flow has significant implications for analyzing underground mine ventilation systems, including the enhancement of surveys and models. Currently, traditional schlieren methods are impractical underground. Background oriented schlieren (BOS) provides a solution to this problem. BOS requires two primary components, a professional quality digital camera and a schlieren background. A schlieren background is composed of a varying contrast repetitive pattern, such as black and white stripes. This background allows the camera?s sensor to capture minor light diffractions, such as those caused by air flow. Although BOS shows great potential for ventilation analysis, sensitivity is an issue. This paper seeks to validate the BOS technique for imaging flow through a regulator by comparing BOS images with traditional schlieren images. This paper also outlines initial experimental efforts used for the validation.

Jan 1, 2011

By M. Barati

A collaborative research between University of Toronto and Hatch was conducted to understand and optimize the process conditions pertaining to a novel steelmaking technology. In this technology, known as CRISP, direct reduced iron is continuously melted and refined in a stationary electric arc furnace. The major challenge against continuous operation of the electric furnace was identified to be minimizing the corrosion of the refractory in order to achieve uninterrupted operation for a minimum of one year. Theoretical analysis and bench scale experiments together with two pilot runs resulted in defining an operating window for slag chemistry that would minimize chemical attack to the refractory while satisfying the oxidizing conditions required for sufficient decarburization. An analysis of the process in terms of energy consumption and emission of greenhouse gases revealed that it is superior to the current batch DRI-based steelmaking technologies.

Jan 1, 2011

By R. P. van Hille, A. W. van Zyl

The BIOX® culture, aiding liberation of arsenopyrite/pyrite occluded gold, is inhibited by thiocyanate (SCN > 1 mg/L); precluding the recycling of tailings water up-stream of the bioleaching circuit. The activated sludge tailings effluent remediation (ASTERTM) process is a biological process that was developed to facilitate water recovery and treat waste water on-site (to achieve a SCN concentration < 1 mg/L) to be recycled or disposed of. The aim of this study was to investigate the effects of changing temperature and SCN loading on the SCN degradation ability of the mixed microbial population clue to seasonal temperature changes and fluctuations of SCN concentration in the waste water.

Jan 1, 2011

The chemical composition of the nodules varies with the type of manganese minerals and the size and characteristics of their nucleus, but those who have an economic interest have the following composition: Mn 29%, Fe 6% Si 5%, Al 3%, Ni 1.4%, Cu 1.3%, Co 0.25%, Na 1.5%, Ca 1.5%, Mg 0.5%, K 0.5%, Ti 0.2 0.2% and Ba 0.2% (Morgan, 2000; ISA, 2002). The Pacific Rim is an area of abundant occurrence of polymetallic nodules (Glasby et al., 1980; Morgan, 2000). According to these authors, the Pacific sea floor of the Clarion-Clipperton Zone (CCZ) is one of the most interesting areas in regard to the genesis of polymetallic nodules. Their abundance in the ocean floor is very variable, as there are places where they cover more than 70% of the ocean floor. The nodules can be found at any depth, but the highest concentrations are between 4000 and 6000m (Morgan et al., 1993). In studies conducted in the EEZ of the Mexican Pacific are those made within the project "Research on the origin, process and distribution of minerals in the Pacific ocean floor in the Exclusive Economic Zone of Mexico". Within this project Rosales (1989) conducted studies on the origin, process and distribution of polymetallic nodules, finding that a number of processes give origin to nodules, being diagenesis one of the main mechanisms of elements that contribute to the nodules. Besides hydrothermal processes that are carried near the East Pacific Rise at 21° N, inputs are contributing to the nodules metallic elements and sediments, especially in regions close to the dorsal, as a greater influence hydrogenetic processes occurs westward (Rosales and Carranza, 1990). In 1993, after cruise MIMAR II, Carranza and Rosales refer that metals such as Cu, Co, Ni, Sn, Fe, Mg, Pb, Zn and Ba may have a relationship with the East Pacific hydrothermal activity and sea currents carry these metals in solution to the Clarion-Clipperton fracture area, where there are hydrogenic metals sources (Al, Fe and Mn).

Jan 1, 2011

By Steven R. Lowe

Construction of a pump station, consisting of an inlet chamber, wet well and pump chamber, required excavation to a depth of 9.7 m (32 ft) below ground surface and more than 7.6 m (25 ft) below the ground water table in a rural, but rapidly developing part of southern New Jersey. Private houses are located [ ] within a few hundred feet of the pump station that use shallow wells for water supply. The pump station design anticipated support of the entire pump station on shallow foundations bearing directly on the underlying natural soils. However, during construction, uncontrolled ground water flow caused ground loss and damage to the bearing qualities of foundation soils. As a result, remedial repairs were required including support of the pump station on drilled pile foundations and releveling of the pump chamber that had settled. This case study is an example of where a poor understanding of the significance of upward flowing ground water had a major impact on the cost of construction. Anticipated subsurface conditions The pump station layout is shown in Fig. 1 with the locations of two borings made prior to construction superimposed. One of the borings was located within the footprint of the deep wet well excavation. Generally, this is not advisable where a deep excavation is required below the ground water table. This is because there is a history of projects where ground water seepage, or pressure, has broken out into an excavation through an ungrouted borehole and compromised the integrity of foundation soils. Logs of the borings did not indicate that the borings [ ] were grouted upon completion.

Jan 1, 2011

By Vinay Kumar, Jae-Chun Lee, Rakesh Kumar, Manis Kumar Jha, Archana Kumari, Pankaj Choubey

Present work is a part of developing novel recycling technique for waste printed circuit boards (PCBs) i.e. the liberation of metals from PCBs by organic swelling followed by the treatment of resin to remove/ recover hazardous soldering materials. In order to recover the hazardous metallic constituent lead from the liberated resin, initially the leaching studies were made using fresh solder containing 63.9% Pb and remaining tin. Experimental results obtained in different conditions viz. time, temperature and acidity showed -97.20% of lead dissolution with 6M HNO3 at solid to liquid (S:L) ratio 1:10 (g/mL) and temperature 90°C in 75 minutes. The result of the studies validated with crushed PCBs shows that almost total lead and tin was leached out with 6M HNO3 and 6M HC1 respectively at S:L ratio 1:10 (g/mL) and temperature 90°C within 50 minutes. The results will be useful for the treatment and safe disposal of PCBs resin.

Jan 1, 2011

By I. A. Kunasz

This paper is not intended to review and re-state general information on lithium, but rather to analyze the paradigm that has caused such a rapid rise in lithium production and the development of new lithium producing centers. Details on pegmatites, brines, concentrate and chemicals are amply covered in a number of publications ? SME?s Industrial Minerals and Rocks, Industrial Minerals, Roskill and a host of other publications. There is no question that the latest interest in lithium has been driven by the potential development of the electric car. This stimulus prompts one to recall two symposia: 1. ?Lithium Resources and Requirements be the year 2000?, organized in 1976 by the U.S.G.S. in Denver (1) and the sequel 2. ?Lithium ? Needs and Resources? at Corning, N.Y. (2).

Jan 1, 2011

By John Noakes

Marine scientists at the University of Georgia, have in the past few years, designed, developed and refined two geochemical survelliance systems for the exploration of hard mineral resources on the seafloor. The one first developed is an underwater sled which contains a nuclear radiation detector for measuring naturally occurring gamma radiation that is associated either with marine phosphorites containing uranium and its decay daughters or thorium decay products that are indicative of monzanite. The latter can, in most instances, be used as a pathfinder mineral for placer deposits that may contain other heavy minerals of interest such as rutile, ilmenite, chromite, gold, etc. This sled is operational in continental shelf depths. The second system is capable of more definitive measurements in the form of direct elemental analyses of the silt and clay fractions within the surficial sediments. It consists of a towed sled containing a submersible pump which, upon agitating the sediments, transfers the finer fraction up a hose to a shipboard centrifugal cone then to an automated sample processor. The resultant samples are rendered into sediment wafers, suitable for non-destructive XRF analysis. The system is capable of shipboard analysis for specific elements within minutes after sampling, allowing a cursory look upon which an exploration grid can be formulated while on site. A much wider spectrum of up to 40 elements can be evaluated when the wafers are returned to the land based laboratory.

Jan 1, 2011

By D. Kwietnewski

With all of the unknowns associated with tunnel construction, how does a contractor choose a roadheader? This paper presents a review of several models of roadheaders being used in today?s tunnel projects. The features of different models of roadheaders are presented and compared. Roadheader size and cutter power generally determine which roadheader is best for a particular job. We will also present a model for matching features of the roadheader to the anticipated ground conditions such that the most efficient machine is selected for the project.

Jan 1, 2011

By V. I. Lakshmanan, R. Roy

"TiO2 is used in paints, plastics, rubber, paper, inks, textiles and other miscellaneous applications. The demand for the pigment grade Ti02 is growing at 3.0%/year on average and this invites the development of innovative and cost effective processes. The current processes are not designed to recycle the reagents and thereby discharge the effluents into the environment, causing an environmental concern.During this study, synthesis of TiO2 from an ilmenite concentrate was investigated using an innovative atmospheric mixed-chloride leach process. The solution purification was carried out using solvent extraction in two stages. In the first stage iron removal was carried out and in the second stage titanium was extracted. The strip solution obtained from the second stage solvent extraction contained the purified titanium and from this stream pigment grade Ti02 was recovered. The barren solution was used for reagent recovery and the regenerated leach liquor was recycled."

Jan 1, 2011

By M. Nzotta, L. Teng, S. Seetharaman, A. Chychko

The objective of the present work is to optimize the EAF practice towards Mo alloying with maximum retention of the alloying element in molten steel. During Mo additions, there were significant losses to the dust (ca 7 %) and to the slag phase (ca 2 %), which had serious economic and environmental impacts. The present work was aimed at designing a suitable Mo precursor, an alternative to ferromolybdenum, as the Mo source and a process sequence for optimal retention of Mo in the steel. The design of the Mo source should be in such a way that low cost raw materials such as MoO3 concentrate have to be used, stable during the addition so that the vapour phase losses as MoO3 are kept minimum and the dissolution of the precursor in molten steel is easy without loss to the slag phase. After thermodynamic considerations, three precursor materials were chosen, viz. CaMoO4, MgMoO4 and Fe2MoO4. Synthetic mixtures of the component oxides in each case as well as pure MoO3 were investigated by TGA and high temperature XRD in order to find out the temperature range in which the compounds were formed. Experiments were also conducted separately where the evolved gases were analyzed. All the three precursors were formed easily and the loss of MoO3 to the vapour phase was found to be extremely low. Addition of the oxide mixtures to steel melts were conducted in three different scales, viz. 16 g, 500 g and 3 tons (induction furnacle). Initial experiments showed that MgMoO4 was not suitable since the Mo yield in the steel melt was not very high. Fe2MoO4 was found to perform best, the Mo yield reaching 98 %. Further trials were conducted in the 65 ton Electric Arc Furnace (EAF) at Uddeholms AB in Hagfors. Mixtures of mill scale, MoO3 and carbon in suitable proportions were added in a pre-determined addition sequence. It was found that, in the actual practice, the Mo yield reached 99 %, equaling in performance the addition of ferromolybdenum. The process offers an effective use of cheaper raw materials and very high Mo yield avoiding a pre-treatment step like the production of ferromolybdenum. This is both cost effective and environmentally advantageous. The process has been patented and is being currently implemented at Uddeholms AB, Hagfors, Sweden.

Jan 1, 2011

By Katsunori Okaya, Gjergj Dodbiba, Hiroyuki Ono, Toyohisa Fujita, Seiji Matsuo

"In an attempt to raise the copper grade of Printed Circuit board (PCB) by removing other components, carbonization treatment was investigated. The crushed PCB without surface-mounted parts was carbonized under nitrogen atmosphere. After screening, the char was classified by size into oversized pieces, undersized pieces and powder. The copper foil and glass fiber pieces were liberated and collected in undersized fraction. The liberation of copper foil from the oversized pieces was also investigated. The copper foil was liberated easily from glass fiber by stamping treatment. Liberation rate of copper foil was high at high carbonized temperature. The experimental results indicated that 90% of oversized char was liberated and the copper foil recovery from PCB carbonized at 1073K was 110kg/t. The copper recovery from char powder by flotation was also investigated. 15% of the copper grade and 80 % of the copper recovery were obtained, whereas the removal rate of silicon was 55%.IntroductionWaste Electrical and Electronic Equipments (WEEEs) should be recycled because they have many kinds of valuable materials and most WEEEs include Printed Circuit Boards (PCBs). In Japan, about 30 km2 per year of Printed Circuit board (PCB) has been produced [1], PCBs are normally separated from WEEEs and picked up by hand and sold to non-ferrous metal market because PCBs include high grade of copper and other precious metal such as gold, silver and palladium [2]. However, PCB also has impurities such as silicon, aluminum and calcium which are slag materials in non-ferrous smelting process, and other harmful elements such as lead, bromine and antimony. Low grade PCBs are sold after removal of invaluable parts or sometimes land filled without any treatment"

Jan 1, 2011

By G. Hamel

The LCL&L process (Low Caustic Leaching & Liming) is a patented hydrometallurgical route developed by Rio Tinto Alcan (RTA) to economically process spent pot lining (SPL) generated by aluminum cells. The three resulting end-products (carbonaceous, fluorinated and caustic liquor) are inert and have valorization possibilities. An industrial size pilot plant located in Saguenay (Quebec) was inaugurated in mid-2008 to demonstrate and optimize the technology. This paper describes characteristics of the LCL&L process and the experience acquired by RTA since the plant&apos;s start-up, including ramp-up capacity and technology challenges that were overcome. Possible end-products valorization methods are also presented. The carbonaceous end-product can be separated into carbon and brick rich fractions and used as either alternative fuel, reducing agents, or as raw material for third party processes. The development of a conversion process for the fluorinated end-product would allow its reuse as a substitute to fluorspar mineral for aluminum fluoride production. Finally concentrated caustic liquor is already valorized at the nearby RTA Vaudreuil alumina refinery.

Jan 1, 2011

By N. Ward

The Gualcamayo Mine is located in the Andes Mountains north of San Juan, Argentina (Figure 1). A property of Yamana Gold Inc, it declared commercial production in July 2009 and has a total mineral reserve and resource base of approximately 88,000 kg of gold. Crushing operations for the open-pit mine are located in a 13,500 m3 underground cavern with a ceiling height of 22 m. More than 3,600 m of tunnels are used to access the cavern and convey the ore. The Project as described in this paper relates to the design and construction of the Main Cavern, Conveyor System Exit Tunnel, the Mechanical System Access Tunnels, and two 4.20 m diameter shafts (Ore Pass #1 and Ore Pass #2) as shown in Figure 2. [ ] Preliminary engineering for the Project was performed by Hatch Chile. Rizzo Associates Argentina, S.A., a division of Paul C. Rizzo Associates, Inc (Rizzo) was contracted to provide geomechanical and geotechnical support for the construction of the access tunnel system and geomechanical design and construction supervision for the cavern and shafts.

Jan 1, 2011

By Qingbo Yu, Qin Qin, Junxiang Liu

"Dry-granulation is a new process of molten blast furnace slag treatment and air is used as heat exchange medium. There are some shortages: poor effectiveness of granulation, high air-slag ratio and high energy consumption, which are the obstacles to popularize dry-granulation. Based on rotary cup atomization, the technique of recovering waste heat of molten blast furnace slag through waste heat boiler producing high pressure steam is exploited. The molten blast furnace slag is granulated to uniform small slag granules with high temperature, and slag granules pour into the waste heat boiler. It could produce steam, obtained in first row and second row tubes, when descending velocity of slag granules equaled 1.1mm/s and the Reynolds number equaled 7100. The application of the system for recovering waste heat from high temperature molten blast furnace slag has a significant meaning.IntroductionBlast furnace slag is one kind of solid waste in iron making process, which is discharged at the temperature range from 1723 to 1923K. In China, there was 0.162 billion tons of slag discharged in 2009, and the energy contained in the slag is equivalent to the energy in 9.4 million tons of coal equivalent. The sensible heat of molten slag is a very valuable waste heat source, so it is worthwhile to recover the sensible heat. At present, the molten slag is treated by a water quenching method. But in this process, the sensible heat is not recovered, moreover, an amount of water is consumed and harmful waste gas is discharged into the environment. Due to the considerations of energy conversation and environmental protection, the iron making industry pays close attention to dry-granulation, which is useful to obtain more benefits [1-4]. The sensible heat is recovered and an amount of water is saved by the method of dry-granulation. The amorphous content of slag granules obtained from dry-granulation is over 95% [5, 6], so the slag granules can be used as a perfect raw material for cement [7, 8].In the late 1970s, the Sumitomo Metal Industries, Ltd. and the Ishikawajima-Harima Heavy Industries, Ltd. jointly undertook the research of rotary drum granulation. This method has several disadvantages: the processing capacity and efficiency are low, and it is not adoptive to operate continuously in production [9]. From 1980, Nippon Steel, NKK, Kawasaki Steel, Kobe Steel, Sumitomo Metal Industries and Nisshin Steel were engaged on air granulation, and the experiments were operated for 6 years on the blast furnace in Nippon Steel. In the process of air granulation, there was great power consumption. The complexity of structure and the great floor space of the air granulation device caused high cost of investment. In 1986, Ukraine exploited a new method of heat recovery referring to the technology of Continuous Casting and Rolling [10]."

Jan 1, 2011

By David Preece

The Thirlmere aqueduct was constructed over 110 years ago to provide water from the Lake District (in the north-west of England) to the city of Manchester some 60 miles (100 km) away. The aqueduct remains, to this day, a key piece of infrastructure in the distribution of raw water in the north-west of England. A short section of the aqueduct was identified as being in poor condition during routine inspections by the owner. Subsequent investigations attributed the conduit damage to the movement of unstable ground over the conduit. Bachy Soletanche Ltd was subsequently appointed to carry out the design and construction of the slope stabilisation works and to undertake repairs inside the damaged conduit. The works were undertaken on an existing slope which, in places stands at a gradient of up to 40º to the horizontal. Strict limitations on plant and equipment were imposed by the client (United Utilities) to ensure that slope and conduit loading and associated vibrations were kept to an absolute minimum during construction. An intensive instrumentation system was installed to monitor surface movements, ground movements at depth, conduit movement and strains across existing planes of weaknesses within the conduit. The solution comprised the installation of spaced piles up-slope and down-slope of the conduit. Restrictions were imposed on the minimum stand-off distance between the outside face of the conduit and the piling works so targeted permeation grouting was undertaken to improve the ?connection? between the conduit and the down-slope piles. The presence of existing sub conduit groundwater flows was suspected and the permeation grouting was focused in areas to minimize disruption to the groundwater regime. The paper presents the basis of the design and highlights the combined construction and instrumentation methods adopted to minimise damage to this valuable asset.

Jan 1, 2011

By L. E. C. Pignatari

Mine reconciliation is seen, for many, as a test of the quality of model estimates, while in fact it should be seen as a powerful tool for detecting and correcting problems in each step of mining operations, from resource estimation to metal production. Adequate reconciliation practices allow a more efficient control of the mining processes; however, its results can be illusory unless all parties involved have been in compliance with the principles of sampling correctness. This paper presents a new, segmented reconciliation matrix, which is based on the Theory of Sampling (TOS), developed to monitor gold operations and reserve estimation.

Jan 1, 2011

By F. Ntengwe

The Konkola Mine, a subsidiary of the Konkola Copper Mines Plc (KCM) which is owned by the Vedanta group of companies of India and Zambia Consolidated Copper Mines Holding limited, is located at Chililabombwe in the northern extension of Zambia&apos;s Copperbelt province. In its operations, the mine has been experiencing problems in ascertaining the optimum degree of fineness and the operating density of the hydrocyclone overflow in order to achieve high flotation performance. It was believed that recovery of sulphide copper minerals from Konkola ore is a function of the fineness of the grind so that it might be an economical justification to modify the grinding plant in order to run at lower cyclone overflow densities than the case is now. In an effort to improve these operations, it was decided to carry out test work on various hydrocyclones of sizes 0.381 m, 0.4575 m and on 0.508 m. The later was found to give satisfactory results and was installed on the plant. Despite giving satisfactory results there was need to investigate further to establish the working densities and size. Increasing the density of cyclone overflow decreases the per cent passing 75 pm at least in the range 1080-1 150 g/l. Furthermore, hydrocyclones give better separation at low densities of feed and hence the efficiency is high at low feed densities. Circulating load increases with an increase in feed densities and an decrease in the grind. The flotation performance in both sulphide and oxide copper minerals rougher stages is enhanced with an increase in the degree of fineness of the grind, with an optimum being obtained at a density of 1 150 g/l and 81.4% passing 75 µm. Keywords Konkola mine, hydrocylone, optimum degree of fineness, sulphide copper minerals.

Jan 1, 2011