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By M. Cambridge

The design process must anticipate all construction and operational conditions and make an allowance for all eventualities. Prevention of failure during operational life, and in some cases post abandonment, requires that a risk assessment is undertaken during the design stage which defines not only the factors of safety to be used but the criteria for the structure during its operating life. These operating criteria should clearly identify the at-risk structures and the inspection and monitoring routines required to ensure compliance with the design objectives. On a mine site, it is the role of mine management to ensure that the operating rules be applied throughout the mine life and that a system of inspection and monitoring procedures be instigated. Where the risks are significant, high-level auditing by an independent engineer will also be required. Within the inspection and auditing framework, the designer needs to incorporate instrumentation to enable the operators and management to confirm that the facility meets the requirements of safety, stability and environmental compliance whilst continuing to meet its operational function. This paper reviews the use of inspection and monitoring to prevent failure and provides, in summary, examples of where monitoring has been undertaken and prevented failure. A tabulated review of legislation, regulations and technical guidance generated as a result of previous failures or untoward events is provided.

Jan 1, 2005

By Robert G. McLusky

Since 1998, environmental extremists have waged war with the central Appalachian coal industry in West Virginia and Kentucky. In particular, they have filed three lawsuits challenging the legality of excess spoil ‘valley fills’ under CWA, NEPA and SMCRA: 1) Bragg v. Robertson, 72 F.Supp. 2d 642 (S.D.W.Va. 1999), rev’d. 248 F.3d 275 (4th Cir. 2001); 2) Kentuckians for the Commonwealth v. Rivenburgh, 204 F.Supp. 2d 927 and 206 F. Supp. 2d 782 (S.D.W.Va. 2002), rev’d. 317 F.3d 425 (4th Cir. 2003); and 3) OVEC v. Bulen, 2004 U.S. Dist. LEXIS 12690, July 8, 2004; OVEC v. Bulen, 2004 U.S. Dist. LEXIS 16078, August 13, 2004.

Jan 1, 2005

By William J. Francart

In 2003, MSHA initiated a survey of the 11 Coal Mine Safety and Health Districts to develop a database for the implementation of Atmospheric Monitoring Systems (AMS) in underground coal mines. Mine operators continue to realize the benefits of improved fire detection capabilities, as the number of mines using the systems, as well as the percentage of mines, continues to increase. Fire detection data and new technology implemented in underground coal mines is discussed as well as regulatory compliance, diesel exhaust considerations and hydrogen interference in carbon monoxide detection.

Jan 1, 2005

After the closure of collieries, they naturally start to fill up with water. As a result, hydraulic gradients develop between them and different hydraulic pressures are exerted onto peripheral areas or compartments within mines. This results in water flow between mines, or onto the surface. This flow is referred to as intermine flow. The collieries in the Witbank Coalfield have geometries such that there are several areas where this intermine flow is possible. Since the Department of Water Affairs and Forestry has declared intermine flow as one of its greatest concerns for granting closure to South African mines, much research into this phenomenon is required. The challenges in determining intermine flow are numerous, and attention has focused on identification of areas where these flows can take place. The quantification of these flows is problematic due to the uncertainties in exact geometric configurations and the variation in site-specific hydraulic properties of thecoal and overlying lithilogical layers. During this study, use has been made of numerical flow modelling and several analytic solutions to test the applicability of the flow models as well as to predict groundwater flow directions, filling times of voids and flow volumes. The numerical modelling methodology entailed a downscaling approach starting with a broad regional model covering the entire area, followed by modelling the interactions between interconnected mines, and finally looking in detail at the major areas of interaction.

Jan 1, 2005

By Michael Gauna, William J. Gray, Joseph C. Zelanko

Mechanized mining in the underground coal industry has continued to evolve since the introduction of the remote control mining machine. Remote control continuous mining machines without an onboard operator’s compartment are now the norm in the industry. Extended cuts in excess of 30 ft (9.1 m) are commonplace. Unfortunately, machine operator positioning has become an often unrecognized safety concern, particularly when remote control continuous mining machines excavate a turn (turn a crosscut). From January 2001 through July 2004, remote control continuous mining machine operators or helpers have been involved in ten roof fall fatalities and eight machinery crushing fatalities. The machinery crushing incidents occurred when machines were being repositioned or moved to another place. Of the ten roof fall fatalities, three occurred while a crosscut was being turned and a fourth fatality occurred while mining was being conducted adjacent to the crosscut. The operating time associated with turning crosscuts is a relatively small part of the mining cycle. In recent years, however, a disproportionate number of fatal incidents appear to have been associated with this activity. Procedures for reducing the incidence of operator fatalities while turning crosscuts are discussed. These techniques include: minimizing the number of turn cuts, limiting turn cut depth, establishing no work zones and using visual warning devices to designate them, installing more roof/rib support in the vicinity of the turn cut, using notch cuts prior to initiating a full turn cut, and positioning the remote control miner operator in nontraditional locations.

Jan 1, 2005

Drum winders have now been built to attain depths of 3000 m and more in a single lift in accordance with the South African Code of Practice SABS 0294, which was introduced at the time of the last hoisting conference in 2000. Since then, this code has not only been followed for several winders in South Africa but was also followed in deep mines in Canada. Design of winders and their braking systems are described in the paper. Koepe winders are in use for high payloads of up to 50 t and to hoisting depths of around 2100 m. As known, the stress range of the hoisting ropes is the key parameter for rope fatigue. However, as per the SABS Code of Practice 0294, relying on static design is not the answer to the question of where the limits are for Koepe installation. The paper describes factors that are recognised to have influence in rope life and suggests definition of new design criteria for friction winders in order to get viable solutions for high-capacity hoisting from deep mines similar to drum hoisting.

Jan 1, 2005

By T. P. Williams, M. B. Rydzewski, B. Corner

Konkola Copper Mines (KCM) plc is an integrated copper producer operating on the Copperbelt in Zambia. KCM has numerous mining operations located in the towns of Chililabombwe (Konkola Mine), Chingola (Nchanga Open Pit and Underground operations), Lusaka (Nampundwe Mine), with a smelter located in Kitwe (Nkana Smelter) and an SX-EW plant in Chingola (Nchanga Tailings Leach Plant). [ ]

Jan 1, 2005

By P. Fauvel, V. Nasri

In January 2001, French and Italian governments signed an agreement for the construction of a new Lyon-Turin railway line. This project includes a tunnel of 53.1 km length and a maximum of 2500 m overburden to be designed for a reference speed of220 km/h. The tunnel crosses major part of the West Alpine geological formations, which are very complex and contrasted in terms of the nature of rocks and the mechanical and hydrogeological conditions. In addition to the twin single-track tubes, numerous intermediary shafts, security station and intervention sites and cross passages should be built to respond to the security, operational and construction requirements. This paper describes the results of the preliminary engineering design and multiple challenges of this very long and deep railway tunnel.

Jan 1, 2005

By L R. B M Sß

This paper presents the results of a liberation study made on a sulfide copper ore from Carajßs, Brazil, in a mini pilot plant flotation test. The aim of the research was the methodological evaluation of a liberation study using a sample crushed at 1 mm and a sample ground for flotation testing to a target size of 80 per cent

Jan 1, 2005

The Callie Underground Mine is located in the Tanami Desert 560 km Northwest of Alice Springs in the Northern Territory and is currently operated by Newmont Australia Limited with all mining activities carried out by Henry Walker Eltin. Callie was discovered in the region in 1991 with the box cut portal commenced south of the pit in 1995 and underground ore production commenced in 1998, after completion of the profitable Callie Open Pit. Development is currently occurring at depths of over 700 m with the decline currently below the 640 Reduced Level (RL) level (surface RL of 1400) with production haulage from 600 m below the surface. The combination of auto compression, a moderate geothermal gradient of 2¦C/100 m and diesel heat transfer causes the wet bulb temperature of intake air at the bottom of the mine to be typically 5¦C higher than on the surface. Wet Bulb temperatures can be up 5¦C higher again in active areas under secondary ventilation. During the 2002/2003 wet season many activities in the lower levels of the mine were stopped due to miners experiencing adverse heat related symptoms or the temperatures exceeding the Underground Heat Management Procedure stop job criteria of 32¦C wet bulb. To improve the working environment, combat the heat related illness and improve operational efficiency, a temporary 1.8 MW refrigerated cooling plant consisting of three 600 kW modules were installed underground to provide bulk air cooling for the lower levels of the mine during the 2003/2004 wet season. Several studies have been conducted in relation to future ventilation demands at Callie and all came to the conclusion, that some mine cooling will be necessary for Callie to meet the high production and development demands. This paper will describe the ventilation network at the Callie Underground operation focusing on the installation, operation and effectiveness of the temporary underground refrigeration plant.

Jan 1, 2005

By Paul Sainato, J. Steven Gardner

Sustainable development is defined as ‘development that meets the needs of the present without compromising the ability of future generations to meet their own needs.’1 There has been considerable debate of late between environmentalists and mining operators concerning the current regulation and operation of mountaintop mining. To those not familiar with the practice, it essentially applies an area mining method to a mountaintop, removing all overburden above coal seams, resulting in full recovery of the resource with the excess or swell spoil material - (rock and dirt) being deposited in engineered fills in hollows to the side (known as hollow fills or valley fills - very similar to highway fills). Because most of the dialogue has been adversarial and mining’s response is perceived to be primarily reactive instead of proactive, a rift in communication and value systems between the two sides has widened. Since 1999, the global mining community has been concerned that there is a disconnect between mining practices and the values of today’s society.3 Working through the World Business Council for Sustainable Development (WBCSD), the International Institute for Environment and Development (IIED) was created to review mining practices in a project entitled Mining, Minerals and Sustainable Development (MMSD) driven by the following four goals:

Jan 1, 2005

By Denise de La Corte Bacci

The Brazilian Regulation NBR 9653 is a guide intended to evaluate mine and quarry blasting effects in urban areas. The first version, written in 1986 by the Committee of the Brazilian Associate of Technical Norms, is currently being revised. Current regulations specify a maximum PPV limit of 15 mm/s (0.59 in/s) without consideration of frequency or type of structures being protected. The present regulation is still a draft and it is not validated. Several different agencies and institutions have participated in the Committee such as the Environmental Agency from the State of São Paulo (CETESB), University of São Paulo (POLI-USP), University of Rio Grande do Sul (UFRGS), National Department of Mineral Resources (DNPM), Aggregate Industry (ANEPAC and SINDIPEDRAS), besides a number of industry representatives, explosives manufactures and independent consultants. The present regulation proposes to modify the limits of particle velocity and introduces new definitions and criteria for evaluation of vibrations, as well recommendations to address blast vibration complaints.

Jan 1, 2005

By Z. Xie

Gas diffusion electrodes (GDEs) for high temperature polymer electrolyte fuel cells (PEFCs) have been prepared using ZrP-modified Nafion ionomer. The performances of these GDEs as cathodes and anodes were evaluated and compared with conventional Nafion ionomer GDEs using Nafion 112 as the PEM under elevated temperature and reduced relative humidity. ZrP-modified Nafion ionomer was incorporated into the catalyst layer to enhance water retention and/or increase the protonic conductivity. The fabrication of ZrP-GDEs was implemented by the ion exchange of Nafion solution with zirconyl chloride, followed by the impregnation of GDEs in H3PO4 solution. The composite electrolytes in the catalyst layer possessed a ZrP content of 20% by weight. GDEs were characterized by TGA, SEM, XRD, and CV. Scanning electron microscopy (SEM) indicated evenly distributed elemental Zr and P within the catalyst layer. Cyclic voltammetry shows a reduced electrochemically-active surface area when the ZrP is incorporated into GDEs. Polarization and impedance analyses indicate the cathode with ZrP-modified Nafion ionomer did not show an enhanced or decreased performance, compared with conventional Nafion ionomer GDEs under elevated temperature and decreased humidity. However, when GDEs with ZrP¬Nafion ionomer were used as the anode, an improved performance was observed. Preliminary experiments show that the anode is more sensitive to dehydration than the cathode under elevated temperature and/or low humidity. Improving the anode water retention capability will help to reduce losses at the anode. However, the incorporation of hygroscopic agents in the cathode catalyst layer is not essential because it is self-humidified by electrochemically-produced water even under elevated operating temperature and lower humidity.

Jan 1, 2005

By G. Balletto

Increasing environmental awareness leads to a reflection on the consequences of a non-appropriate use of mining resources. In this sense the determination of the mining requirements for the building industry is the necessary prerequisite to activate planning in mining according to the principles of environmental sustainability. Experience shows that there is a relationship between the production of buildings in relation to the shape of the city and the resulting demand for minerals. The increasingly urgent demand for maintenance and restructuring by existing buildings will stretch further the demand for minerals with an excessive, no longer sustainable withdrawal, which will lead to focussing greater attention on environmental policies oriented to the use of alternative materials including materials from recycling. It is pointed out moreover that the joint action of land use planning and mining planning leads to interesting applications that have significant repercussions on the environment.

Jan 1, 2005

By Antoine F. Mulaba

Introduction Copper and cobalt oxide mineral deposits formed by the atmospheric weathering of near surface sulphide deposits are commonplace in the Democratic Republic of Congo. The most common route for the extraction of these metals is a hydrometallurgical one in which the base metal oxides are dissolved in sulphuric acid and then concentrated further by solvent extraction. However, as many of these deposits are relatively low grade (i.e. 0.5-1.8%Co and 2-4% Cu) and can also contain large amounts of acid consuming gangue minerals (i.e. dolomitic, micaeous, and/or siliceous), the hydrometallurgical route becomes uneconomic due to the excessive acid leaching costs. Some means of pre-concentration ahead of leaching is then desirable to improve the process economics. Apart from the small scale mining (Pan. Afr. News Agency, 2000) handpicking, although not easy, oxide concentration by flotation has been suggested. For the flotation process, the two most common approaches are controlled potential sulphidisation (CPS) and the fatty acid flotation method. The preferred method is dictated by the nature of the mineral makeup of the gangue. Being secondary deposits, the gangue associated with these ores is often complex and can play a significant role in the overall flotation efficiency. Laboratory flotation experience gained from the testing of a number of different ores of this type has revealed that it is not possible to prescribe a set method for the flotation of various ore types. Each ore needs to be analysed very carefully before and after laboratory flotation on an individual basis in order to arrive at an acceptable flotation technique Laboratory flotation testwork was carried out on three different samples from the DRC in attempts to isolate some of the more important variables affecting the flotation of copper and cobalt oxide minerals from these weathered deposits. This paper describes some early results achieved and experiences gained with these different ores ahead of a more detailed flotation test program which will follow in the near future on receipt of a significant quantity of a more representative sample. Controlled Potential Sulphidisation (CPS) was used in an attempt to achieve acceptable recoveries of both copper and cobalt.

Jan 1, 2005

By Mehmet Maral

Various types of Tertiary (Miocene) lignite occurrences had been formed and alternated with volcano-sedimentary Bigadiç Formation in the field of study, which resides in the middle and eastern parts of Biga Peninsula. The focus of the study is to identify the geochemical and petrologic properties of coal occurrences and the formation mechanism of the deposits. A comparative study of the deposits will also be studied. Biga Peninsula is a very rich zone in terms of both metallic ores and industrial minerals. Most of the metallic deposits and industrial occurrences in the region have been known and mined throughout the history. This richness of the region is related to the volcanic and tectonic activities that have developed during different geological periods. These activities are the main reasons of weathering and alteration phenomenon.

Jan 1, 2005

By R Balusu

This paper provides an overview of computational fluid dynamics (CFD) modelling capability developed by CSIRO with the aim of improving the knowledge of flow migration dynamics within longwall goaf areas. The CFD models can be used to study the ingress of oxygen into the goaf in different ventilation scenarios and goaf drainage arrangements. This approach not only helps the design of effective gas control strategies but also the management of spontaneous combustion risk in the goaf. Innovative goaf inertisation strategies have been developed and implemented during longwall sealing operations. Work is continuing to develop general guidelines of proactive goaf inertisation strategies to suppress the development of spontaneous heating behind active longwall faces.

Jan 1, 2005

By H El-Shall, R Stana a

An innovative process for the separation of carbonaceous minerals from bulk ores is presented. In this process, the surface of carbonate minerals is reacted with acid used to nucleate CO2 bubbles at the particle solution interface. Entraining the liberated CO2 gas at the surface via coating agent renders the particle more buoyant providing for a selective separation from non-carbonate containing masses. Different surfactants were tested to stabilise the bubbles and float the particles. In this paper, separation of dolomite from apatite using PVA (polyvinyl alcohol) as a coating agent, is discussed. Interestingly, up to 10 mm particle sizes can be floated. Moreover, flotation of a phosphate and dolomite mixture was carried out and MgO content

Jan 1, 2005

By Troy Holm, Matthew L. Fuller, Frederick H. Earnest

Virtual Reality Animation Of The Proposed El Dorado Mine In El Salvador Assists Regulators In Reviewing An EIA

Jan 1, 2005

By Atsuo Inoue, Toshihiro Ogata, Hideaki Sugihara

Generally in Japan, since ANFO has easy handling and low-price, it is most used as industrial explosives. However, ANFO is very easy to dissolve in water, it is difficult to use under existence of water and the consumer have desired water-resistant ANFO which has perfect water resistance. Then, we have developed the Water-Resistant Granular Explosive (It is written as following WRGE.) in which the surface of the explosive was covered by waterproof film, so that WRGE is able to use in hole with water. We ran various performance tests about the WRGE developed in the laboratory. Consequently, WRGE has water resistance of over 6 hours, and it has been checked that a performance and handleability were equivalent to the conventional ANFO. Then, we carried out the field test in the consumption site, and did performance evaluation on an on-site level. As compared with ANFO, fragmentation (size and volume) and handleability are almost equivalent. However, some problems which the WRGE is not settled out smoothly in hole with water and need more time for loading were also clarified. We are going to continue some advanced improvements through field tests.

Jan 1, 2005