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By T Mizuta, T Nakano, D Ishiyama

The Tamagawa Hot Spring, from which Ra-Pb-Sr-bearing barite precipitates, is a representative hot spring in a volcanic gas-bearing hydrothermal system associated with Quaternary andesitic to dacitic magmatic activity beneath the Yakeyama Volcano. Thermal water in the Tamagawa Hot Spring is divided into three types: Cl-SO4-type (Ohbuki hot spring: pH 1.2); SO4-type (pH 1.8 to 2.9); and neutral-type (pH 6.1). The concentrations of dissolved components in the Ohbuki Cl-SO4-type thermal water are about ten times higher than in the SO4-type thermal water. The 87Sr/86Sr isotopic signatures of the Ohbuki Cl-SO4-type thermal waters (0.703992 ¦ 0.000004 to 0.704032 ¦ 0.000006) are different from those of SO4-type thermal waters (0.704245 ¦ 0.000003) formed by the interaction of andesitic volcanic rocks (0.704065 ¦ 0.000007 to 0.704093 ¦ 0.000009) and groundwater derived from river water (0.704314 ¦ 0.000012 to 0.704519 ¦ 0.000013) in a shallower part of the hot spring area. The possible origins of Sr in the Ohbuki Cl-SO4-type thermal water and in the SO4-type thermal water are different. The Sr isotopic ratios (0.704130 ¦ 0.000012 to 0.707556 ¦ 0.000014) of Aniai Formation andPreYakeyama Lake deposits occurring below the hot spring area are distinctly higher than those of the Cl-SO4-type thermal water. However, it is expected that a solidifying andesitic or dacitic magma which has similar Sr isotopic ratios of the Ohbuki Cl-SO4-type thermal water, occur in the deep portion of the Tamagawa Hot Spring. The Cl-SO4-type thermal waters having low Sr isotopic ratios do not acquire their Sr isotopic signatures by interaction with strata below the hot spring area, but they are likely to reflect water interaction with a solidifying magma with low Sr isotopic ratios. Components including rare metals in Cl-SO4 type thermal water could be transported from a deeper part. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Willem J. Marais

The management of unpaved mine road networks on large surface mines rarely results in optimal road maintenance strategies and minimised total road-user costs. This is ascribed mostly to the complex and dynamic combination of variable road networks and loading and discharge points. In a dynamic mining environment - typically those mines in which production is managed by a centralised truck dispatch system ? there is no guarantee that a particular road maintenance intervention will contribute significantly to reducing total road-user costs or increasing productivity. Most large surface mines operating ultra-heavy mine trucks rely on an integrated on-board diagnostic data collation, communication and GPS-asset location system as a real-time fleet management tool. By extending this system to incorporate a multi-sensor analytical procedure in which specific truck vital signs are monitored and filtered, a road defect can be recognised and a trigger level set to relay the location of defects on the mine haul road to the centralised truck data management system. Previous work established the feasibility of the multi-sensor approach to road defect recognition on large mine haul trucks, and outlined the defect recognition, analytical and modelling issues and system limitations. This paper presents the development of the analytical procedure used as a basis for evaluating the truck on-board data to establish maintenance priorities amongst a network of mine roads. Following an introduction to the system architecture, the results of system field trials are analysed and the results discussed in the light of defect density and traffic volume as the primary variables in an approach to prioritising road maintenance. The paper concludes that by supplementing the existing mine communication and asset management systems, road maintenance can be managed on a near real-time basis and maintenance equipment dispatched to where most immediate benefit will realised from a maintenance intervention on the network, thereby generating the maximum improvement in service and reduction in cost per ton hauled.

Jan 1, 2008

By M A. Gontalves, A F. D C Varajpo

The Rio Capim kaolin district, located in the north-east of Parß State, Brazil, constitutes one of the worldÆs largest high-whiteness kaolin reserves for the paper coating industry. It contains, at the base of the main ore, a soft kaolin that gradually changes at the top into a ferruginous duricrust followed by a flint kaolin. The flint kaolin is completely discarded during the exploitation of the soft kaolin. With the view of a more complete beneficiation, aiming at a sustainable development of the minerals industry, the use of this residual flint kaolin has been considered for the manufacturing of zeolites. Zeolites were synthesised from the flint kaolin through a reaction between metakaolinite with soda at 80¦C, for durations of 24 to 144 hours. The transformation into metakaolinite was carried out at 800¦C and was not affected by the titanium oxides. For a synthesis time of only 24 hours, a zeolite 4A very close to its theoretical definition was obtained, whereas for synthesis times longer than 96 hours, a slight formation of hydro-sodalite was also observed. The synthesised zeolites were tested as cationic adsorbents on 0.5 molar solutions of Cu, Pb, Cd and Zn. The adsorption was measured for contact durations of one and three days. It was noted that the exchange kinetics were slow and that the retention was significantly greater after three days than after one day. The retention was greater than 50 per cent of the theoretical exchange capacity for Pb, Cd and Zn, which was different to Cu, where the retention exceeded its theoretical exchange capacity.

Jan 1, 2008

By K. Ram Chandar, Vedala Rama Sastry

Fragmentation and muck pile profile together play an important role in optimizing the excavation costs for given geo-mining conditions. Initiation system is one of the vital parameters influencing the fragmentation and muck pile throw (profile). An attempt is made through this paper to study the characteristics of muck pile produced in addition to fragmentation. Two new parameters namely “throwburden ratio” and “muck pile ratio” are proposed for assessing fragmentation and movement of material. Field investigations were carried out in a limestone mine in southern India with shock tube and detonating cord initiation, using four initiation patterns, keeping other parameters like burden, spacing,delay timing etc. same.

Jan 1, 2008

By D G. Miljak, J Khachan, B K. Schwitter

The performance of prototype magnetic resonance sensors suited to mineral measurement in conveyor, slurry or portable applications is described. The sensors can be positioned around conveyors and modified slurry pipes, providing deep penetration of the sensing field, relative insensitivity to ore surface conditions and high mineral discrimination. Measurements on slurry, concentrates and ores sourced from mine operations are presented for two applications. Firstly, the quantitative measurement of chalcopyrite in slurry was demonstrated in laboratory measurements. In a calibration test, a standard error of 0.1 wt per cent and detection limit of 0.3 wt per cent was obtained. Secondly, results were obtained for the discrimination of iron ore texture. Signals were readily observed using measurement integration times of seconds to several minutes, depending on ore material. The results demonstrate the feasibility of online quantitative analysis of selected minerals in processing applications using magnetic resonance.

Jan 1, 2008

By L. Becze, B. Pierre, S. Di Carlo, G. P. Demopoulos

From January to June 2007, the autoclave production at the Kidd Metallurgical Site was severely affected as a result of plugged discharge lines and extensive precipitation/crystallization of sulphates that caused massive scaling in different autoclave compartments. Work was performed at McGill University to understand the root causes. The crystallization of zinc and ferrous sulphate salts was investigated in terms of solubility measurements. Scale samples were characterized using chemical and mineralogical-spectroscopic analysis. In this paper, following a description of the Kidd zinc pressure leach operation, highlights from this investigation are presented and solutions used to overcome the problem are outlined.

Jan 1, 2008

By D MacKay, W J. Bruckard

One of the mining worldÆs greatest challenges is to effectively use consumables (ie reagents and grinding media) to maximise metallurgical response, while minimising operating costs. It is anticipated that this paper will provide a logical frame work within which this can be achieved. The current study, at PerilyaÆs Broken Hill concentrator in the lead primary grinding/roughing circuits, examines the dependency of collector adsorption on Eh. The data demonstrates clearly that under the right grinding chemistry the addition of a xanthate collector during grinding can improve galena flotation. Further, operating the ball mill under the desired grinding chemistry regime leads to significant reductions in collector consumption whilst maintaining the metallurgical benefit.

Jan 1, 2008

By Douglas Anderson

In the early 1980s, a method for controlling blast vibrations other than by modifying the Scaled Distance came into use. Research studies had indicated that blast vibration could be simulated by detonating a signature hole with the vibration monitored at critical locations, and then using a computer to superpose the waveforms with varying delays. By choosing delay times that create destructive interference at frequencies that are favored by the local geology, the “ringing” vibration that excites structural elements in houses and annoys neighbors could be reduced.

Jan 1, 2008

By D Bradshaw, J R. R de Villiers

The non-stoichiometric sulfide mineral pyrrhotite (Fe(1-x)S), common to many nickel and platinum group element (PGE) ore deposits, occurs in varying crystallographic forms with the different types exhibiting subtly different physical and chemical properties. These differing properties are likely to influence the flotation performance of pyrrhotite, which in the case of PGE operations is actively recovered, whereas in nickel operations pyrrhotite is depressed. In this study, examination of natural pyrrhotite samples from Southern African and Canadian nickel and PGE ore deposits revealed a variety of pyrrhotite compositions in terms of iron content (Fe7S8, Fe9S10, Fe11S12) and solid solution nickel concentration. Pyrrhotite composition was correlated with its mineral association depending on whether non-magnetic pyrrhotite occurred in conjunction with troilite, non-magnetic pyrrhotite occurred as single phase pyrrhotite, magnetic pyrrhotite occurred as single phase pyrrhotite or whether the two phases; magnetic and non-magnetic pyrrhotite co-exist. Subsequent microflotation tests of selected single phase pyrrhotite samples revealed that the non-magnetic pyrrhotite is slightly more floatable than magnetic pyrrhotite. Microflotation tests also showed that varying flotation responses occur between differing magnetic pyrrhotite samples. These differences in flotation performance are postulated to be a result of the effects of varying pyrrhotite crystallography, trace metal content and mineral association on pyrrhotite oxidation, formation of surface species and subsequent adsorption with xanthate collector.

Jan 1, 2008

Geologists often classify ore textures on the basis of the origin of the rock in which they form and the grade of one or more minerals within the ore (Sinclair and Blackwell, 2002, pp 32-36).  Metallurgists, on the other hand, need to know how best to process the ore in order to extract the valuable minerals from it (Petruk, 2000). Geological classification has the following disadvantages:it requires the services of skilled economic geologists, of whom the supply has been dwindling for many years;it is subjective, depending on the perceptions of the individual geologists who make the classification; andit may relate only weakly to processing requirements of the ore. We describe methodology for automatic classification of ore textures from images of drill core. The images analysed are æclassifiedÆ images, in which a particular mineral (or mineral group) is assigned to each pixel. The new methodology is intended to:provide a quantitative and reproducible alternative to traditional geological texture classification,relate to process mineralogy of the ore, andimprove the ore-texture-related input to orebody domaining and geostatistical block models.

Jan 1, 2008

Current mine production planning, scheduling, and allocation of resources are based on mathematical programming models. In practice, the optimized solution cannot be attained without examining all possible combinations and permutations of the extraction sequence. Operations research methods have limited applications in large-scale surface mining operations because the number of variables becomes too large. The primary objective of this study is to develop and implement a hybrid simulation framework for the open pit scheduling problem. The paper investigates the dynamics of open pit geometry and the subsequent material movement as a continuous system described by time-dependent differential equations. The continuous open pit simulator (COPS) implemented in MATLAB, based on modified elliptical frustum is used to model the evolution of open pit geometry in time and space. Discrete open pit simulator (DOPS) mimics the periodic expansion of the open pit layouts. Function approximation of the discrete simulated push-backs provides the means to convert the set of partial differential equations (PDEs), capturing the dynamics of open pit layouts, to a system of ordinary differential equations (ODEs). Numerical integration with the Runge-Kutta scheme yields the trajectory of the pit geometry over time with the respective volume of materials and the net present value (NPV) of the mining operation. A case study of an iron ore mine with 114 000 blocks was carried out to verify and validate the model. The optimized pit limit was designed using Lerchs-Grossman?s algorithm. The best-case annual schedule, generated by the shells node in Whittle Four-X yielded an NPV of $449 million over a 21-year mine life at a discount rate of 10% per annum. DOPS best scenario out of 2 500 simulation iterations resulted in an NPV of $443 million and COPS yielded an NPV of $440 million over the same time span. The hybrid simulation model is the basis for future research using reinforcement learning based on goal-directed intelligent agents.

Jan 1, 2008

By C. Pamukcu

In this paper, which is aimed to serve as a review article, first of all a breakdown of the earth?s total water reserves is given. The usage areas of water in the mining industry are mentioned and these uses are briefly outlined, together with the main pollution potential of each. According to this, most of the water (almost 80% of it) is utilized in processing. Later on, probable damages that the mining would give to groundwater as a result of acid mine drainage, heavy metal pollution, euthrophication and deoxygenation is described. Finally, the measures and controls that should be taken against water contamination in mines are presented.

Jan 1, 2008

By Jeongbok Seo

This paper describes successful application of driven tapered-steel-pipe piles for two large-scale projects in the New York metropolitan area: Rego Park Mall, Rego Park, N.Y. and 164 Kent Avenue, Brooklyn, N.Y. The combination of side friction and end bearing resistance produced by tapered-steel-pipe piles has been well-recognized as greater than the side friction and end bearing resistance by pipe piles. Forty-four tapered piles were driven and tested at these two sites. Design pile load for the two sites was 260 kips for Rego Park Mall and 400 kips and 300 kips for 164 Kent Avenue. To measure the pile-drive hammer efficiency, the compressive stress in the pile, and to estimate the ultimate bearing capacity of the pile, dynamic load testing using a Pile Driving Analyzer (PDA) was conducted on index piles at the sites. Subsequent to the field testing, data analysis using the Case Pile Wave Analysis Program (CAPWAP) was conducted. Restrike PDA analysis and full-scale static load tests were performed on the selected test piles. Test piles at the project sites exhibited significant time-dependent increases in bearing capacity caused by the effects of "set-up" or "soil freeze." The dissipation of excess pore-water pressure in the soil, which had been disturbed and remolded by driven pile, was generally considered the primary cause of set-up. The increase at the subject sites ranged from 100 to 300 percent of the capacity measured at the initial driving. This paper discusses the results of various types of load testing on tapered piles and the set-up effects by comparing PDA test results acquired during and after pile driving. Finally, an empirical relationship for the New York metropolitan area has been offered for quantifying set-up.

Jan 1, 2008

By R. A. Franks

An evaluation of a nuisance-emissions-discriminating smart mine fire sensor system was made in an operating coal mine. These field evaluations were conducted to determine the sensor system?s ability to discern nuisance emissions, such as diesel exhaust, emissions from flame cutting and welding operations or hydrogen gas from a charging station, from real fires and to compare the number of falsely reported fire alarms generated between the sensor system and a standard carbon monoxide (CO) monitor. The sensor system?s ability to operate successfully in the working environment of an operating coal mine was also evaluated. The smart mine fire sensor system consisted of four sensors whose data outputs were fused with the use of a neural-network-type computer program. Long-term trials were conducted in a haulage way, a belt entry, and a track entry. The system functioned successfully in the belt entry, in accordance with its developmental goals, where the sensor system even discriminated events not anticipated during development. It was not totally effective in the haulage way and track entry, though, due to a combination of significant diurnal air temperature variations, dust, and mechanically induced vibrations. Also, deteriorating rib conditions contributed to operational problems in the haulage way evaluation. In general, the smart mine fire sensor provided nuisance emissions discrimination and was shown to be a viable new approach for mine atmospheric monitoring, enhancing miner safety. This paper describes the in-mine evaluation of the smart mine fire sensor system and discusses recommendations for improving the system. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.

Jan 1, 2008

By Leslie Taylor, W. L. Fourney, Uli Leiste

Over the past few years, our laboratory has been investigating the loading on vehicles due to the detonation of buried explosives. We have been using target plates to represent the bottom of the vehicles that were being subject to the forces from the detonating explosives. Parameters shown to be important in the blast loading were type of soil, stand off distance (distance from the surface of the soil to the bottom of the target plate), and depth of burial (distance of the charge center of gravity to the sand surface). We conducted over the first year of our work a large number of tests which looked at the impulse being applied to the plates as a function of depth of burial, stand off distance, and type of soil. Of the three parameters we found stand off distance to be most important, depth of burial to be the next most important parameter, with type of soil least important. We also found that impulse could be scaled with explosive size quite accurately and that results (for impulse) were quite repeatable from one test to the next.

Jan 1, 2008

By D. Tao

The presence of insoluble slimes in potash ore poses a serious processing problem to the potash industry. These insolubles must be removed prior to potash flotation because of their high adsorptive capacity for amines which are generally used as collectors in the subsequent sylvite flotation. This is usually accomplished by scrubbing of the ore in brine followed by hydrocyclone classification to separate slimes from the salt particles. Insoluble slimes that remain in the ore after the desliming procedure are depressed by reagents such as guar gum or starch during sylvite flotation. In this research, the feasibility of using GP clay binders to replace guar gum for potash flotation was investigated. Batch mechanical flotation tests were conducted with the potash samples provided by a leading potash company. It has been found that GP clay binders increased potash concentrate yield and recovery at the same product grade. Effects on potash flotation efficiency of flotation process parameters such as impeller rotation speed, slurry temperature, binder type, dosage and conditioning time have been investigated to establish the optimum conditions for flotation. Binder GP374G33 has been identified as the optimum substitute for guar gum as slime depressant in potash flotation.

Jan 1, 2008

By Adil Aledresse, Louis Mercier, Laxman Amaratunga

"The development of high capacity adsorbents with uniform porosity denoted, MP-HMS (Mercaptopropyl – Hexagonal Mesoporous Structure) using nanotechnology, and their ability to extract gold from solution, is presented. The preparation of highly effective heavy metal ion adsorbents by the incorporation of thiol moieties into the pore channels of mesoporous silica molecular sieves has been the subject of many nanotechnology research investigations. The unique feature of these nanoporous adsorbents is their ability to adsorb gold ions from ultra-low concentration solutions like mine effluent as well as from leached solutions in gold mills. The preliminary studies from laboratory simulated gold solutions show that the adsorption capacities of these materials are also among the highest reported. MP-HMS has shown the capability to adsorb 370 mg gold per one gram of the nanomaterials from Tetrachloroaurate solution (up to 37% of their weight). Experimental studies indicated that the maximum adsorption of gold (as high as 99.9% recovery). The current studies will be extended to investigate the interaction of ionic gold complexes with nanomaterials. Future development of this work may lead to either to replace the conventional CIP/CIL processes or use nanomaterials in tandem with the former, suggesting plausible use of mesoporous material in pulp, MIP or in leach, MIL, as a novel gold extraction process.INTRODUCTIONGold typically occurs at very low concentrations in ores less than 10 g/t or 0.001% (mass basis). At these concentrations the use of aqueous chemical (hydrometallurgical) extraction processes is the only economically viable method of extracting the gold from the ore. Typical hydrometallurgical gold recovery involves a leaching step followed by the separation of the gold bearing solution from the residues, or adsorption of the gold onto activated carbon adsorbent. After elution from the activated carbon the gold is further concentrated by precipitation or electrodeposition."

Jan 1, 2008

By Amanda C. Lima, Luiz Augusto H. Terrones, Sergio N. Monteiro

"Fabric from weaved yarns made of jute fibers have been considered as reinforcement for polymeric composites. In particular, these fabrics obtained from discarded sackcloth are presently being investigated as environmentally friendly composites with recycled polyethylene matrix. The objective of the present work was to compare the practical properties and economical aspects of these composites with those of conventional materials such as wooden board and gypsum panels for building application. The comparison showed that, depending on the amount of post-used jute fabric, a cost/benefit analysis favors these composites over the conventional materials.IntroductionThe increasing amount of wastes generated by human activities is becoming a worldwide problem of pollution with growing consequences to the environment. The question on how to dispose these wastes is, therefore, a major global issue. Among the possibilities of it gating the problem, the use of materials with characteristics of being renewable, biodegradable and recyclable is considered an environmentally correct solution. Examples of this type of materials are left over lignocellulosic fiber from coconut husks and sugarcane bagasse [1] that, after the primary extraction of edible pulp and juices, can be recover for industrial application. Nowadays, the main use of these fibers is to reinforce polymeric composites applied as components for building construction and automobile parts [2,3]. In addition to these applications, composites reinforced with residual lignocellulosic fibers may replace conventional furniture and panels made of wood and thus help to reduce deforestation [4].Environmental protection is not the only motivation for recycling natural fiber wastes. In developing regions activities associate with collecting and processing residual fibers provide job opportunities for low-income people. Moreover, if the lignocellulosic fiber is collected as a recyclable waste, it hes the economic advantage of a comparatively cost, which constitutes in a relevant difference as a choice for commercial utilization."

Jan 1, 2008

The purpose of the Lower Lea Valley Cable Tunnel project is to relocate the overhead power lines circuits, which currently cross the proposed site for the 2012 London Olympics in East London. This was the first contract to be awarded as an Olympic project and is on the critical path for the proposed Olympic Park as the construction of the Olympic village, stadium and other venues cannot begin until the tunnels are complete, the cables installed and the overhead power lines removed. The tunnelling works for the scheme include two parallel tunnels between Hackney and West Ham. Each tunnel is approximately 6 km in length. One tunnel is 4.15 m ID and connects the National Grid substations. The other is 2.82 m ID and connects the EDF Energy substations. The tunnels were constructed through mixed ground using four earth pressure balance tunnel boring machines. These were driven simultaneously from two drive shafts within a single site. The 12 km of main tunnels were constructed within a year from start to finish, with completion in June 2007. The shafts range between 6 m and 15 m ID. These were constructed using a combination of caisson sinking and underpinning techniques. Dewatering was adopted to suit the groundwater conditions.Other works include the design and construction of the head house buildings, cable and ventilation culverts, mechanical and electrical (M&E) installations and all associated works. In addition to the above, a further 1 km of tunnel and two shafts were added to the project scope connecting the EDF Energy tunnel to the substation at Bow. These additional works provided further challenges to the project to ensure that these works were constructed within the program constraints for the 2012 London Olympics. This involved refurbishing one of the tunnel boring machines from the main EDF Energy tunnel drives and relaunching the machine to construct the Bow tunnel. The Bow tunnel was constructed within two and a half months, with the tunnel boring machine breaking through in August, ahead of schedule. The main challenge presented by this project is the program constraints. This project outlines the requirement for team work between the client, stakeholders, contractor and designer in order to provide program certainty. A close working relationship between the contractor and the designer is required to provide value engineered, time-saving solutions to mitigate the risks associated with the design and construction program.

Jan 1, 2008

By Erik Nygaard

During the last years, ammonium nitrate has been involved in several accidents worldwide. This have caused increased focus on security and safety issues and resulted in:• Revised Yara standards • Revised international standards for storage and transportation • Stricter regulations from national authorities in many countries.

Jan 1, 2008