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By Donald P. Tuchman, Justin R. Patts, Emanuele G. Cauda, Andrew B. Cecala, Elaine N. Rubinstein

Video techniques for monitoring exposure, such as NIOSH’s “Helmet-CAM,” employ both real-time dust monitors and mobile video cameras to assess workers’ respirable dust exposures. Many real-time personally worn dust monitors utilize light scattering sensing elements, which are subject to measurement biases as a function of dust type (size, composition, shape factor) and environmental conditions such as relative humidity. These biased and inaccurate dust measurements impair the monitor’s ability to properly represent actual respirable dust concentrations. In the testing described, instrument mass concentration data was collected using three different types of commonly used commercial off-the-shelf personal dust monitors and compared to a reference standard. This testing was performed in a calm air (Marple) dust chamber in which three units of each make and model (for a total of nine monitors) were used for each test. Equivalency factors (EF, a multiplier to match the Thermo TEOM 1400a reference instrument) ranged between 0.746 and 1.879 across all dusts and environmental conditions tested, and between 0.821 and 1.519 on the ISO test dust.

By Donald P. Tuchman, Justin R. Patts, Emanuele G. Cauda, Andrew B. Cecala, Elaine N. Rubinstein

Video techniques for monitoring exposure, such as NIOSH’s “Helmet-CAM,” employ both real-time dust monitors and mobile video cameras to assess workers’ respirable dust exposures. Many real-time personally worn dust monitors utilize light scattering sensing elements, which are subject to measurement biases as a function of dust type (size, composition, shape factor) and environmental conditions such as relative humidity. These biased and inaccurate dust measurements impair the monitor’s ability to properly represent actual respirable dust concentrations. In the testing described, instrument mass concentration data was collected using three different types of commonly used commercial off-the-shelf personal dust monitors and compared to a reference standard. This testing was performed in a calm air (Marple) dust chamber in which three units of each make and model (for a total of nine monitors) were used for each test. Equivalency factors (EF, a multiplier to match the Thermo TEOM 1400a reference instrument) ranged between 0.746 and 1.879 across all dusts and environmental conditions tested, and between 0.821 and 1.519 on the ISO test dust.

By William J., Coulter

IN the early days of Colorado mining, between 1880 and 1900, when Leadville, Kokomo, and Robinson were boom mining camps, the entire area around Climax for a matter of fifteen miles was overrun with prospectors, so the mineralized outcrop at Climax was not unknown. The principal interest in minerals during this period was in gold, silver, and lead, and since the Climax outcrop showed none of these it drew little attention. Geology played an important part in bringing prospectors to the very edge of the Climax deposit. The Mosquito fault, which crosses near the base of Bartlett Mountain, continues as an important geological structure, at least as far as Leadville some twelve miles distant, and at the base of Bartlett Mountain the vertical throw on the fault is estimated to be between 2000 and 5000 ft. The sedimentary beds known to the Leadville district are all present on Bartlett Mountain to the north of the Mosquito fault, which cuts them off abruptly, and exposes the Pre-Cambrian rocks that underlaid them, so the prospectors, who were searching for gold, silver, and lead in the sediments

Jan 1, 1946

In the last 30 years, human appropriation of global renewable resources has accelerated to the point where 35 per cent of the earthÆs land surface is now in managed agro-ecosystems, consumptive water use consumes between 50 per cent and 85 per cent of freshwater supply and 60 per cent of ecosystem services are utilised in an unsustainable manner. There are virtually no landscapes in which renewable resources are not already fully allocated among different economic and environmental uses. Furthermore, it is increasingly recognised that water availability issues do not exist in isolation but are linked with the related environmental issues of biodiversity preservation, the carbon cycle, soil degradation, and energy use and supply. It is against this background that the sustainable management of water in mining is increasingly developing a strategic viewpoint where water is viewed as a resource within an interconnected landscape, having economic, environmental and social value and providing a range of environmental services in the provision of public and private goods. This paper explores the issues associated with sustainable management of water in mining from a strategic viewpoint. The cumulative impacts of multiple water users, both within and outside the mining sector, is increasingly threatening the security of supply for all users. To quantitatively assess the ætrueÆ value of water it is necessary to: Better understand the science of ecosystem functioning and how human actions impact on environmental processes. Develop appropriate policy, finance and governance structures to support innovative programs that preserve ecosystem function and services (including market based instruments). Apply knowledge as interventions across landscapes in ways that maximise benefits and minimise unintended consequences taking into account differences in the value of water among sectors. A strategic viewpoint of water management relies on knowledge to guide decision making that has been acquired at a range of scales from mine site to mining region. This knowledge must be based on rigorous science, sound data and syntheses of different types of information. Strategic management of water resources will better position the industry in terms of understanding the risks posed by complex, interlinked environmental issues that are increasingly impacting on future access to land and renewable resources, including water, thereby ensuring miningÆs future social licence to operate.

Jan 1, 2009

The last issue included a discussion of recent indications of a 1983 recovery and a brief analysis of the contribution of the U.S. mining industry to the gross national product (GNP). In this issue we present sales and other data indicating the strength of the 1983 recovery and quantitatively analyze the structural shifts that have taken place in the U.S. economy and mining industry since 1972, and changes in electricity consumption by the mining industry. U.S. Economic Recovery The tentativeness in the February/March issue of Minerals and Materials regarding the strength and sustainability of the U.S. economic recovery can now be replaced with a note of increased confidence. Real growth of GNP on an annual basis in the first quarter of 1983 was 2.5 percent, compared with 1.4 percent predicted in the Economic Report of the President.1/ Preliminary second-quarter 1983 data provide further cause for optimism. Recently released data indicate that consumer spending is playing a key role in the recovery. Retail sales have increased significantly across a wide array of goods, especially consumer durables, where sales increased 4 percent from March to April (table J) and were 12 percent higher in April [ ] than the 1982 monthly average. Consumer durable sales were led by sales of building materials spurred by the growth in residential construction, motor vehicles and parts, and household durables, including appliances and furniture.

Jan 1, 1983

By S. Klingmann, G. Blackwell

"Terrestrial photogrammetry has been used for many years to build three-dimensional pictures for analytical purposes. Photographs can include images from open pit mine walls, ground topography, mine buildings infrastructure or accident scenes. Analysis and co-ordinate estimation in early photogrammetric systems demanded the use of specialized and costly optical-mechanical stereocomparators. Few of these instruments could be interfaced with computers to provide databases, and all required trained personnel with good perspective vision to collect data.Digital photogrammetric software has replaced these older systems, and the digital video plotter (DVP) is a simple computerized system utilizing readily available PCs to quickly produce a stereoscopic model of any scene where an area of overlap exists in photographs taken from two different locations. Specialized cameras providing reference marks or grids on the photographs are still necessary for detailed analysis in three dimensions.This paper describes the application of DVP to the three-dimensional analysis of strike, dip and location of dominant fracture planes visible on an open pit wall slope, and the intersection of planar features which might reduce wall stability. Where reference survey points cannot be provided because access by personnel to the photographic scene is impossible for safety reasons, normal case terrestrial photogrammetry can provide the necessary control points for more complex aerial photogrammetry geometries.DVP recreates the geometry existing at the moment photographs are taken, providing the user with the ability to safely recreate, compare and analyze the structures determining the stability of open pit wall slopes."

Jan 1, 2003

By W. F. Visser

The growing availability of information and data analysis capabilities of recent years provides new opportunities for improving the performance of mining operations. By using real-time measurements and artificial intelligence, it is possible to respond faster to changing conditions, while accurate and timely information permits rapid evaluation of changes and fast business improvement decisions. This article presents a blueprint for alignment of systems, organizational design, and management practices to leverage these developments in performance-driven operations management in mining and mineral processing. The first component of the blueprint is a performance framework with a system of key performance indicators for production control that can be used across organizational levels. This system places improvement at the core of management activities, giving greater importance to improvement skills at lower organizational levels, so companies can leverage available information for improving operational control. Secondly, the blueprint defines an organizational structure that strengthens performance improvement with technological and change management capabilities. Finally, the blueprint proposes alignment of management practices, covering the optimization of short-interval controls, the application of an improvement project portfolio management system that determines the ownership of improvement projects, and the coordination of controls across the organization. This combination of systems, organizational design, and management alignment supports rapid decision-making at the right organizational level. Introduction of the presented blueprint for operations management enables mines to leverage the developments in information and analysis capabilities to improve the performance of operations.

By I. R. Hanby

A simple but comprehensive method has been developed for the simulation of a mechanical-drive dump truck that enables various parameters to be predicted as a function of time throughout its whole cycle. Uses of the simulation results are indicated with specific attention to environmental and operational or economic planning. The output of a sample run is presented. The method can be easily adapted for the investigation of a wide variety of mobile plants.

Jan 4, 1992

By L Snyman, S Webster and J Samosir

Northparkes is located 27 km north of the township of Parkes in central New South Wales, Australia. The operations consist of underground block cave mines and an ore processing plant, which produces high-grade copper and gold concentrate. Production is currently sourced from the E48 Lift 1 block cave mine and open cut stockpiles. Mining commenced at Northparkes in 1994 as an open cut operation. Underground block cave mining began in 1997. Northparkes was the first mine in Australia to use the highly efficient block cave mining method, which relies on gravity and natural rock stresses to fragment and recover the ore.The E48 extraction level is located approximately 581 m below surface and consists of ten extraction drives and 214 drawpoints. Several stress measurements carried out at various levels in both E26 and E48 indicated a low underground regional stress environment and a low to moderate stress state in the E48 orebody. The E48 block used a post undercut strategy that was initiated in 2009, with production commencing in September 2010 and cave-through to the surface occurring approximately four months later in January 2011. Changes to the cut-off grade and fixed prices meant that Northparkes was able to develop an additional two drives to the north of the existing cave and one additional drive to the south. Modelling of the cavability of the additional drives indicated that the cave would not readily propagate to sufficient height of draw to mobilise the ore and tended to arch over to the existing cave shape. Based on modelling and a desire to reduce the risk of the project, preconditioning was adopted. Along with the requirement of safely hydrofracturing an active cave, a measure of the success of the preconditioning was desired. Few block cave operations have developed extension drives adjacent to existing caves.This paper summarises the lessons learnt from the development of this extension project, with a specific focus on ground control and monitoring.CITATION:Snyman, L, Webster, S and Samosir, J, 2016. E48 cave extension at Northparkes, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 111–118 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By W. G. Freeman

This study provides recommendations for improved safety in underground blasting procedures based on in-mine observations of blasting practices in 30 underground metal, non-metal, and coal mines, and the analysis of blasting accidents since 1970 and existing state and federal regulations pertaining to the storage and use of explosives. Results of these analyses and observations indicate that 1) blasting accidents have declined but are an important contributor to the hazards of underground mining; 2) existing regulations are essentially adequate; 3) greater emphases should be placed on human errors and unsafe practices and the enforcement of existing regulations; and 4) future revisions of these regulations and standards should be organized, and their intent coordinated to eliminate ambiguities.

Jan 1, 1980

By A. A. Wessels, D. P. Allison

"Mine hoists are built to handle a certain nameplate capacity; they are specified and designed according to the required duty. However, as production capacity increases in other parts of an operation, the hoist capacity can become the critical constraint. Such a situation occurred at Lundin Mining’s Neves-Corvo operation. This paper examines how each component of the existing hoisting system was examined and optimized. Through a combination of engineering study and hoist simulations, the annual hoisting capacity was improved by 24% through increases in payload capacity and available hoisting time combined with a reduction in cycle time, while no changes were made to the hoist motor, drum or headframe. The additional payload capacity was achieved by reducing the mass of the hoist ropes and skips, and improving load monitoring systems. The cycle time was reduced through the shortening of the creep distances and increased availability through the installation of a shaft collar safety platform, alternative guide rope bushes, and superior liners for both the skips and underground measuring flasks. Enhanced cooling of the hoist electrical system was also incorporated to increase hoist availability by reducing downtime during hot summer months. The changes will increase the capacity from the current 4.5 mega tonnes per annum (Mtpa) to a planned 5.6 Mtpa and are being implemented over a 2-year period whilst maintaining the mine production during the upgrade work. INTRODUCTION Neves-Corvo Mine Neves-Corvo is primarily a copper and zinc mine producing copper, zinc and lead concentrates. The operation is owned and operated by Somincor, the Portuguese subsidiary of Lundin Mining. Located in the Alentejo district of southern Portugal, the operation is situated approximately 15 km southeast of the town of Castro Verde, where summer temperatures can reach as high as 45ºC, and approximately 220 km southeast of Lisbon. The principal means of mine access is via a ramp from surface, with the vertical shaft used to hoist ore and waste from the 700 m level, while conveyors descend from the 700 m level to transport ore and waste up from the deeper levels of the mine. The mine is highly mechanized and several different stoping methods are employed, with the most significant being bench-and-fill and drift-and-fill. The Neves-Corvo mine currently exploits five orebodies: Neves, Corvo, Graça, Zambujal and Lombador for copper and zinc-lead ores which are processed in one of two plants. All the orebodies are currently exploited over their full elevation with the exception of Lombador which is only mined down to the 220 m level, approximately the top 50% of the orebody, known as Lombador Phase 1."

Jan 1, 2019

By T A. J Hopper, B J. Birt, K K. Trofimczyk

Nuclear magnetic resonance (NMR) has been utilised in the oil and gas industry for over 60 years. The technology was recently identified as having potential value in iron ore, where latent bound moisture may affect ore handling even after dewatering and extraction. The first step in introducing this technology to iron ore involved laboratory tests on drill core samples. These results established the parameters for a downhole borehole magnetic resonance (BMR) tool for iron-rich environments, which was subsequently developed. A major challenge involved shrinking what is a very large tool in the oil industry to a slimhole, lightweight, 1-man deployable mining tool.Of primary concern was the ability to measure the very fast transverse relaxation times (T2s) seen in the lab results on iron ore samples. Iron creates local field gradients that significantly decrease the T2 times. As a result, the BMR tool had to be able to measure T2s in the range of hundreds of microseconds, a level not required in clastic sedimentary formations. The choice of T2 cut-offs in iron ore is critical to successfully separating the free and bound fluids. The industry has typically focused on T2 cut-offs in clastics and carbonates, but not in systems with high iron content. Using core analysis results (poro-perm and NMR) we were able to verify the BMR response. The T2 cut-offs were determined from NMR core analysis and then applied to the logs so as to provide a continuous, calibrated permeability log.Field results that highlight the challenge involved in logging in iron-rich environments are presented, as well as some minimum requirements for a successful BMR log. Examples from boreholes in an active iron ore mine in the Pilbara iron ore province in Western Australia are presented, as well as explanations for how NMR data can be combined with bulk density logs to provide a continuous dry weight density log based on the original density-porosity equation from Alger et al (1963).CITATION:Hopper, T A J, Trofimczyk, K K and Birt, B J, 2017. Development of a slimhole downhole nuclear magnetic resonance tool for iron ore – some applications and limitations, in Proceedings Iron Ore 2017, pp 473–480 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By W. Burger

For the development of deep hard rock mines fast access to the orebody is critical. In some cases the mineralized area is more than 1500 m (5000 ft) below surface. Excavation of shafts or declines is typically on the critical path of the project schedule. Saving time on those activities can significantly increase the net present value of the mining project. Mechanical excavation methods are a step-change in excavation performance and labor safety compared to drill and blast operations. In hard rock conditions roadheaders can not be used effectively, so disc cutting is the first choice. For excavation of declines tunnel boring machines (TBM) can be used in many cases. These provide in certain rock conditions considerably higher production rates compared to drill and blast excavation.

Jan 1, 2010

E. E. Russell Tratman, New York City (communication to the Secretary): Mr. Glenn's paper brings up again the question of the part played by coal-dust in colliery-explosions. In the discussion of Sir Frederick Abel's paper on " Accidents in Mines," read before the Institution of Civil Engineers,? much was said about the dangerous properties of coal-dust, and several instances were given of the successful use of a spray of water, water and compressed air, or exhaust-steam from an engine, to keep the mine SUEciently damp to prevent the formation of dust clouds. Methods of preventing shots from blowing out; of using water cartridges to prevent flame ; and of using lime cartridges, wedges and other means of breaking down the coal were also discussed. Mr. Emerson Bainbridge referred to the explosive termed " roburite " (ammonium nitrate and

Jan 1, 1895

By M. B. Kime

"A set of experimental batch leaching tests studied the effect of pH, time, temperature, and stirring speed on the relative Cu, Co, Ni, and Fe leaching yields of an oxidized copper-cobalt ore sample in an aqueous hydrochloric acid solution. The results were statistically analyzed and modelled using the structural equation modelling method. Models showed that Cu, Co, and Ni leaching yields were strong functions of the leaching time and leaching temperature, whereas the Fe leaching yield depended on the leaching temperature, stirring speed, and pH. Under optimum leaching conditions yields were 99.8% Cu, 82.4% Co, 91.3% Ni, and 30.6% Fe.RÉSUMÉ Une série d’essais expérimentaux de lixiviation en bâchée ont été menés pour étudier l’effet du pH, de la durée d’attaque, de la température et de la vitesse de brassage sur les rendements relatifs de lixiviation du cuivre (Cu), du cobalt (Co), du nickel (Ni) et du fer (Fe) d’un échantillon de minerai de cuivre-cobalt oxydé dans une solution aqueuse d’acide chlorhydrique. Les résultats ont été analysés et modélisés statistiquement à l’aide de la méthode de modélisation par équation structurelle (SEM, de l’anglais structural equation modelling). Les modèles ont montré que les rendements de lixiviation du Cu, du Co et du Ni dépendaient énormément de la durée d’attaque et de la température de la lixiviation ; le rendement de lixiviation du Fe, quant à lui, dépendait de la température de la lixiviation, de la vitesse de brassage et du pH. Dans des conditions optimales de lixiviation, les rendements étaient de 99,8 % pour le Cu, de 82,4 % pour le Co, de 91,3 % pour le Ni et de 30,6 % pour le Fe. INTRODUCTIONThe Katanga province in the Democratic Republic of Congo hosts the northwestern part of the Central African Copperbelt. This region abounds with large, rich deposits of sulfide and oxidized copper-cobalt ores. In general, the main valuable minerals present are malachite (CuCO3Cu(OH)2) and heterogenite (CoO(OH)). Common impurities found in heterogenite are Cu, Ni, Si, Al, Mn, and Fe. The substitution of Co by other cations (e.g., Cu, Ni, and Fe) has an influence on the crystallinity of heterogenite (Deliens, 1974). In general, well-crystallized varieties of heterogenite have lower impurity contents, whereas amorphous heterogenite types usually contain more impurities (Thys et al., 2009). Further, in heterogenite, Co can occur in the 2+ and 3+ oxidation states. The gangue generally consists of quartz (SiO2), talc (Mg3Si4O10(OH)2), kaolinite (SiO2·Al2O3·2H2O), limonite (Fe2O3·3H2O), and goethite (FeO(OH)). Oxidized copper-cobalt ores are often treated by hydrometallurgical methods, whereas sulfide ores are often treated by flotation or pyrometallurgy, depending on their grades. Hydrometallurgical methods typically entail selectively dissolving the metals of interest (Cu, Co, and Ni) in aqueous solutions (leaching), transferring the dissolved metals to an organic solution, and retransferring these to a second aqueous solution (solvent extraction). Copper and nickel are readily dissolved in an acidic aqueous media. In contrast, cobalt is difficult to dissolve, especially if it is present in the third oxidation state; however, this species becomes soluble after it is reduced to Co2+ (Mwema, Mpoyo, & Kafumbila, 2002; Kime & Makgoale, 2016)."

Jan 1, 2017

By Grant C. Lukey, Jannie S. J. van Deventer

"The environmental effects of the mining and mineral industry include destruction of natural habitats, changes in river regimes and water tables, and other serious ecological impacts. In this century, it is likely that water will become a critical resource, and in most countries the mining industry competes for a share of this resource. The Kyoto Protocol may at first seem only relevant to the coal mining and power industry, however, it should not be forgotten that the mining and mineral industry is a significant consumer of power. Therefore the ratification of the Kyoto Protocol by most developed countries and the introduction of a carbon credit trading scheme will impact on the industry by potentially increased costs in utilities and waste discharges. It is clear therefore that the mining industry faces many challenges in the coming years. The mining industry?s commitment to sustainable development needs to continue to evolve, in order to meet these challenges effectively. With the advent of globalisation of the industry, it is now an opportune time for the industry to gain international agreement on how they want the industry to achieve sustainability in future years; such a progressive approach is necessary, otherwise government will force the industry to change, which may not necessarily be the best outcome for the industry.INTRODUCTIONThe Earth Summit in Rio de Janeiro in 1992 was an opportunity for world leaders to assemble and discuss strategies and initiatives that provide for further industrial growth without adverse effects on the environment. The World Summit on Sustainable Development held last year in Johannesburg, South Africa, was an opportunity to evaluate those initiatives implemented over the past 10 years, and to set a new and sustainable direction for the future. It is clear that industrial and technology development will continue at a rapid pace in order to serve the needs of a growing world population, but it is essential that the course of this development is well planned, well executed, and that it is sustainable. In reality, while government officials and politicians continue to debate policy and international protocols, the environment continues to suffer and the effects of climate change and global-warming become more real each day."

Jan 1, 2003

By A G. Rogers

This paper discusses the lubrication of surface and underground mining machinery and equipment from the standpoint of machine components. The machine components considered are bearings, cylinders, gears, chains, couplings, fluid drives, hydraulic systems, screws and wire ropes. The best selection of lubricants for these machine components, and for sub-divisions of the components, are outlined. They form general recommendations, for average operating conditions in both surface and under-ground mining operations. The American Petroleum Institute's service classification of both engine crankcase oils and gear oils is de-scribed and used in recommending products for these applications. The practical aspect of lubrication is kept foremost in the recommendations, which are designed to meet the requirements of a wide variety of equipment with the minimum number of lubricants. THE lubrication of mining machinery and equipment presents a variety of problems peculiar to the industry. The type of mine, the ambient temperature, water, dust, and operating and maintenance practices, as well as the age and condition of the equipment, are variables which have to be considered in making lubricant recommendations.

Jan 1, 1963

Outsourcing of specialist and non-continuous services is common practice in international mining operations. There is an increasing trend towards this practice in South Africa as a result of the major organisational changes that have taken place in the industry, and as lower revenues and production cost pressures have reduced profit margins. Many specialist functions have been outsourced in the industry for a long time, an example being shaft sinking, which is undertaken by specialist shaft sinking contractors. In the professional services area, some activities have been outsourced, for example the design and construction supervision of tailings dams, but mining related activities such as geology, mine planning and scheduling, engineering, ventilation, and rock engineering, have traditionally been carried out by in-house staff. In this paper some of the industry problems which have led to an increase in outsourcing of professional services are considered. Then the pros and cons of outsourcing are dealt with before outlining the factors which should be taken into account in choosing an outsourcing partner.

Jan 1, 1999

By S. L. Bell

Most Australian longwall coal mines are currently working coal faces up to nine kilometres from the surface. In the event of a mine emergency walking this sort of distance wearing breathing apparatus becomes very difficult if not impossible. Self-rescue continues to remain the focus of mines rescue in Australian coal mines and this paper describes a vehicle modification which will improve the chances of a miner rescuing himself. Existing mine personnel transport vehicles are not designed to operate in some types of atmospheres that may be present following a mine fire or explosion event. An Australian Coal Association Research program (ACARP) funded research project recently completed in Australia has developed a specification for a vehicle that is able to operate safely in some types of post emergency atmospheres. During the course of this investigation, diesel and electric vehicles were examined prior to making a final decision on vehicle suitability. Based on the fact that there are already some 1500 diesel vehicles in use in underground coal mines in Australia it was decided that modifications to existing diesel engines would be the best option. This presentation will outline the proposed specification for the vehicle and the reasons behind the decisions that were made with respect to the specification.

Jan 1, 2003

By Stephen C. Tadolini, Peter A. Gray, Robert Hawker, Andrew Sykes

"Self-drilling rock bolts (SDRBs) that use pumpable cement grout to anchor bolts have been used successfully in the tunnelling and civil engineering industries for many years. Pumpable cement grout offers a considerable advantage in that the SDRB can be fully encapsulated right down to the bearing plate, including filling cracks and cavities in the borehole. However, cement grout cannot provide the immediate rock support required for the coal industry. This paper describes a new SDRB system that uses pumpable resin to anchor the SDRB in a borehole, which not only provides all the advantages of a pumpable grout anchoring system, but also provides immediate roof and rib support as required in the coal industry. This paper further outlines the latest developments in SDRB technology including (1) extendable self-drilling rock bolts, which can almost double in length during the installation process and are particularly suited to low seam heights and rib support and (2) pre-tensioned SDRBs, where a pre-tensioned load can be applied during the installation process. These new SDRB systems offer both considerable advantages in rock support and improvements in mining productivity.INTRODUCTIONThe mining industry is continually striving to develop more efficient methods to support the roof and walls of roadways and tunnels, and rock bolting has proven to be one of the most significant improvements in ground support over the last 50 years. Rock bolting is now almost universally used in the underground mining industry worldwide, and there are many different rock bolts available.Rock bolts are traditionally made from steel or fiberglass and are anchored into a borehole with a friction-anchoring device, such as an expansion shell mechanism; cement grout; or chemical resin. Friction-anchored bolts are widely used in the Australian metal mining industry, predominantly as short-term support. They are used in conjunction with resin-anchored bolts where there is a requirement for longer life. Resin-anchored bolts are used in the coal mining industry.Friction-anchored bolts provide immediate rock support, but their load transfer capacity is poor compared to resin or cement anchored bolts. In addition, friction-anchored bolts are more susceptible to corrosion than resin or cement anchored bolts."

Jan 1, 2010