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By K. J. Oliver, A. G. Meyers, S. P. Hunt

Deformation Rate Analysis (DRA) and porosimetry have been used to demonstrate the “stress memory” effect in rock and to estimate the vertical in-situ stress in samples of fine-coarse grained sandstone and carbonaceous mudstone. The results of this study indicate that the stresses predicted using both methods are similar to those determined from depth and density of the overburden rocks. The results confirmed that DRA was still applicable even when the core had been sampled 18 months prior to testing. Additionally, the DRA results were modelled using the software PFC2D. A uniaxial test was modelled using the same rock parameters as those observed for the actual core samples. This numerical technique can be used as an aid for DRA results analysis, and can also be used to predict the minimum stress level at which the DRA technique is applicable. The results confirm that any rock mechanics laboratory having standard test equipment could apply the DRA method combined with standard UCS testwork to determine the in-situ stress. Mit der Analyse der Deformationsrate (DRA) und der Anwendung der Porosimetrie wird der Spannungsgedaechtnisseffekts (Stress Memory Effect) im Fels demonstriert, und es werden Abschaetzungen fuer die vertikale in-situ Spannung einer Probe aus mittelgrobem Sandstein und carbonierten Lehmstein getroffen. Die Ergebnisse dieser Untersuchung zeigen, dass die mit Hilfe dieser beiden Methoden ermittelten Spannungen sind vergleichbar. Die Ergebnisse bestaetigen, dass DRA noch anwendbar ist, wenn die Proben schon 18 Monate vor Untersuchungsbeginn gesammelt worden sind. Darueber hinaus wurden die DRA Ergebnisse mit Hilfe des Sofwarepakets PFC modelliert. Ein einaxialer Test wurde mit genau die gleichen Felsparametern, die fuer die eigentliche Probe gelten, modelliert. Diese numerische Methode kann sowohl als eine Unterstuetzung fuer DRA Ergebnisanalyse als auch zur Ermittlung der minimalen Spannung, bei dem die DRA Methode noch anwendbar ist, herangezogen werden. Die Ergebnisse bestaetigen, dass jedes Felsmechaniklabor, das mit den ueblichen Testgeraeten ausgestattet ist, die DRA Methode in Kombination mit dem Standard UCS Testarbeit zur Bestimmung der in-situ Spannungen anwenden kann. L'Analyse du Taux de la difformité (DRA) et les porosimetry ont été utilisés démontrer le " effet de la mémoire " du stress dans roc et estimer le stress dans - situ vertical dans échantillons de grès du grained fin grossier et mudstone carbonifère. Les résultats de cette étude indiquent que les insistances ont prédit utiliser les deux methods est semblable à ceux déterminés de profondeur et densité du surchargez des rocs. Les résultats ont confirmé ce DRA était encore même applicable quand le coeur avait été goûté 18 mois avant tester. En outre, les résultats DRA étaient des modelled qui utilisent le logiciel PFC2D. Une épreuve de l'uniaxial était modelled qui utilise les mêmes paramètres du roc comme ceux observé pour les réels échantillons du coeur. Cette technique numérique peut être utilisée comme une aide pour DRA résulte analyse, et peut aussi être utilisé pour prédire le niveau du stress minimum à que la technique DRA est applicable. Les résultats confirment que tout laboratoire des mécaniques du roc qui a le matériel de l'épreuve standard pourrait appliquer la méthode DRA combinée avec testwork UCS standard pour déterminer le stress dans - situ.

Jan 1, 2003

The Institute was founded in 1894 as the Chemical and Metallurgical Society of South Africa. In 1904 it was reconstituted as the Chemical Metallurgical and Mining Society of South Africa and in 1956 it became the South African Institute of Mining and Metallurgy. The objects of the Institute are to advance the science and practice of mining and metallurgy, to afford opportunities for the interchange and recording of knowledge of mining and metallurgy and to ensure high standards of professional conduct and competence. Membership benefits include monthly issues of the Journal of the Institute, General Meetings at which papers are read, symposia, excursions to mining and industrial concerns and the use of club facilities at Kelvin House. Technical journals received on an exchange basis are available to members at the Johannesburg Public Library. The current membership of the Institute is over 1 600. Membership applications are accepted from suitably qualified persons and the requirements for entrance to the various grades of membership are summarised below. Fellows shall not be less than 30 years of age, shall be university graduates in pure or applied science or shall produce evidence to the satisfaction of the Council that they have successfully completed a co-ordinated course of study in pure or applied science of at least three years' duration at an approved university or institution deemed by the Council to be of equivalent status. Members shall have been employed in senior technical positions in important mining or metallurgical undertakings for at least five years or they shall have practised as mining or metallurgical consultants for at least five years. They shall be practising their profession at the time of application. Entrance fee R10,00, Annual subscription R20,00. Letters of designation: F.S.A.I.M.M. Members shall be not less than 25 years of age and shall be university graduates in pure or applied science, or shall have successfully completed co-ordinated courses of study in pure or applied science of at least three years' duration. They shall have been engaged in work of an approved technical character in the mining or metallurgical industries, of which not less than two years shall have been in positions of responsibility. A candidate shall be practising his profession at the time of his application. Entrance fee R8,00, Annual subscription R18,00. Letters of designation: M.S.A.I.M.M. Associates shall be not less than twenty-five years of age, and shall have been engaged in positions of responsibility in, or associated with, the mining or metallurgical industries for periods of not less than three years. If, however, the candidate for admission to the higher grade of Associate, is at the time of his application, already a Student, he need satisfy the Council only that he is, at the time of his application, engaged in a position of responsibility in or associated with the mining or metallurgical industries. In all cases the applicants shall satisfy the Council that they are fit and proper persons to become Associates. Entrance fee R8,00, Annual subscription R18,00. Graduates shall be not less than 21 years of age and shall be university graduates in pure or applied science, or have completed co-ordinated courses of study in pure or applied science of at least three years' duration at an approved university or institution. They shall not remain Graduate members after attaining the age of 30 years without the permission of Council. Entrance fee R2,00, Annual subscription R12,00. Students shall be persons not less than 18 years of age who are being educated or trained in a manner approved by the Councils to occupy a technical position in or associated with the mining or metallurgical industries and who, furthermore, shall not have attained the qualification required for a higher grade of membership. They may remain Students until they have obtained the necessary qualifications for transfer to a higher grade of membership, but not after the end of the Institute's financial year in which they attain the age of 28 (twenty-eight) years. They shall then transfer to a higher grade to retain membership of the Institute. The Council may relax the provisions of this clause in such cases as it considers appropriate. Entrance fee nil; Annual subscription R5,00. Other. The Council has the power to elect to the grade of Fellow or Member, candidates who may not fulfil all the requirements for entrance to these grades but whose status, professional achievements and practical experience in mining or metallurgy justify such election. Applications. Requests for membership application form should be addressed on the attached form to the Secretaries South African Institute of Mining and Metallurgy, P.O. Box 61019, Marshalltown, Transvaal.

By K. Moxham, B. McKeown

The South African gold and platinum deposits were formed in very different ways and yet both have many similarities. They are flat dipping tabular orebodies, extremely narrow and located in hard abrasive country rock. The mining methods employed are also similar. Primary access is via shafts or declines; secondary access is via haulages and cross-cuts; and tertiary access is from raises. The proposed solution for rapid access described in this paper is focused on the haulages and cross-cuts.

Jan 1, 2006

The established shared laboratory facilities between the Departments of Metallurgy and Chemical Engineering of the Vaal Triangle Technikon and the University of Potchefstroom are already proving to be a great success.

Jan 1, 1992

By D. G. Davies

Colloquium on the construction of Slimes dams The following contributions to the discussion at the above Colloquium were received for publication. D. G. DAVIES* This contribution is really a follow up on Mr H. E. Cross's paper on the conversion of a uranium plant to the recovery of zinc (published in the Journal, November 1973). Ecological aspects of slimes-dam construction by H. T. CLAUSEN C. M. VAN STADEN* Published in the Journal, December 1973 I should like to thank Mr Clausen for his paper and to congratulate the Research Laboratories and the Vegetation Unit of the Chamber of Mines on the excellent work they have done in the past, are still doing at present, and, we hope, will continue to do in future, on the testing of various methods for the covering of slimes dams and specifically on the vegetation of dams. The impact of slimes-dam formation on water quality and pollution by R. T. RUDD* C. M. VAN STADEN Published in the Journal, December 1973 I should like to congratulate Mr Rudd on the paper he presented. Congratulations are also due to the Department of Water Affairs for the practical attitude they have taken in implementing the Water Act. Slimes-dam construction in the gold mines of the Anglo American Group by W. T. RUHMER W. R. FLOOK* Published in the Journal, February 1973 Methods for the construction and operation of slimes dams in the gold-mining industry do not appear to have changed much for some considerable number of years.

Jan 3, 1974

By C. Fiore, A. Kok, W. C. Coningsby

Quarrying is a comparatively simple process which is open to certain economic pitfalls, One of these is the appropriate size of the equipment needed to meet demand.

Jul 1, 1970

By C. Sawmliana

Deep-hole blasting operations in opencast mines are always associated with some annoyance to the surrounding areas in terms of ground vibration, noise, flyrock, etc. These become more severe when underground mines run parallel to them. Blasting in opencast mines may pose danger to the underground mines in terms of roof/side failures, damage of water dams, isolation/ventilation stoppings and other underground installations. The paper discusses a case study in India on the impact of deep-hole blasting in Ramagundam Opencast Project ? III on the stability of various water dams of GDK-6B Incline coal mine operating in close proximity. The stability of underground water dams of GDK-6B Incline mine was endangered due to deep-hole blasting at OCP-III. There were 15 water dams in seam 3 and 16 dams in seam 4 of the underground mine. The physical strength tests using a Schmidt Hammer instrument were carried out in all the 15 water dams of No. 3 seam and 16 water dams of No. 4 seam. The test revealed that there is a decrease in compressive strength values of three dams of seam 3, namely 6A, 6B and 7. Theose three dams were also directly connected to the water source. Water seepage was also observed from the surfaces of the three dams. However, they were found to be stable in accordance with their design parameters and damage point of view while considering a threshold value of ground vibration as 25 mm/s. It was found that the value of tensile stress generated by a vibration of 25 mm/s was much lower (i.e. 0.171N/mm2) than the tensile strength of the two weakest concrete dams (1.85 N/mm2). Ten experimental blasts were conducted at different working benches of the opencast mine and the ground vibration data were recorded in roof and pillars near various underground water dams. The maximum value of vibration data recorded was 5.9 mm/s in roof near dam no. 1 in seam 3 with the dominant peak frequency of 22 Hz. No adverse effect on either of the dams was observed after that blast. During the period of study, no deterioration/adverse impact was found in any dam of the mine. Based on the results of the study and the analyses of the data, optimized blast design parameters and explosives weight per delay were suggested for the opencast mine to maintain the safety of the underground water dams. Keywords: Opencast blasting, damage, water dams, underground mine, ground vibration

Jan 1, 2009

By H. J. E. Hamel

Some aspects of the deformation behaviour and temperature rise during instantaneous compression loading of high purity aluminium By H. J. E. HAMEL The influence of deformation speed on the deformation behaviour of high purity aluminium was investigated. By varying the initial height-to-diameter ratio a considerable influence on the deformation behaviour could be noticed. Lubrication of the specimen end faces was found to have an influence on the flow behaviour and on the roughness of the specimen interface at pressing platens. The results of temperature measurements during deformation agree with work-hardening behaviour of the specimens. Flow curves calculated with the measured temperature rises do not agree with results obtained at lower strains by other workers. The possible reasons are discussed.

By R. P. King

The University of the Witwatersrand (Wits) and the minerals industry of South Africa have grown with the city of Johannesburg. The former has provided teaching and research in mining and metallurgy, while the latter has been responsible for the practical training of metallurgists and for the testing and implementation of innovative ideas proposed by the academics. This interplay between inventiveness and industrial application is illustrated by three examples: the establishment of the iron and steel industry as a result of the persistent experimentation undertaken by Professor G. H. Stanley, the first Professor of Metallurgy and Assaying at the South African School of Mines, which later became Wits; the establishment of the research organization that eventually became the Council for Mineral Technology (Mintek) - again through Professor Stanley's faith in the role of research; and the establishment at Wits of physical metallurgy as a discipline in its own right, as first suggested by Professor C. E. Mavrocordatos of Wits against the opinion of his colleagues in the industry. The Department of Metallurgy at Wits has been well supported by the minerals industry. Not only does the industry provide grants for the financial support of students, but it supplements the salaries of personnel in the Department, making possible the recruitment of top-class academic staff. At present the greatest problem is the lack of interest shown by matriculants in the metallurgical industry as a career. However, an enormous effort is being made by the Chamber of Mines, The South African Institute of Mining and Metallurgy, and the Wits Department of Metallurgy to ensure that matriculants receive appropriate information about the career prospects in the minerals industry.

Jan 1, 1983

By R. Kumar, N. R. Mandre

"The beneficiation of iron ore slimes by selective flocculation was studied. Polyacrylamide (PAM) and guar gum were used as flocculant, along with sodium hexametaphosphate (SHMP) as a dispersant. The samples collected were initially subjected for chemical and mineralogical studies. The mineralogical studies indicated the presence of haematite and goethite as the principal iron-bearing minerals, with quartz and kaolinite as gangue minerals. The selective flocculation tests showed that the Fe grade can be enhanced from 58.24% to 64.60% Fe at a recovery of 66.33% using polyacrylamide as the flocculant. A Fe grade of 63.20% at a recovery of 68.04% was obtained using guar gum as flocculant. The efficacy of the studies was analysed using a separation index, which indicated that the higher separation index was obtained with the tests employing polyacrylamide as the flocculant. IntroductionIndia is endowed with huge reserves of highgrade iron ore and is one of the prominent producers in the world. As the high-grade iron ores have been exhaustively mined, it has become imperative to use low-grade iron ores, fines, and slimes to meet the growing demand. Also, generation of fines and slimes during mining and processing contributes to loss of minerals to the extent of 30% of the total value (Mandre and Panigrahi, 1997). These fines/slimes are often discarded as waste into tailing ponds, containing considerable amounts of iron. Therefore beneficiation of tailings/slimes has become necessary for optimal utilization of the resources.In recent years, interest in recovery of valuable minerals from low-grade ores, slimes, and tailings has increased worldwide. These activities are initiated not only to recover minerals but also to address various environmental issues associated with fine particle treatment. The literature reveals that several technologies have been employed in this regard, including flotation, advanced gravity separation, and high-intensity magnetic separation. However, these processes are found to be ineffective for fine particle treatment due to lower collision probability in flotation, decreased gravitational effect in gravity separation, and reduced drag force in magnetic separation, among other factors (Batisteli and Peres, 2008; Das et al., 2007; Dworzanowski, 2012; Rocha, Caneado, and Peres, 2010). Therefore, it is in this regard that selective flocculation has gained importance in treating slimes in recent years."

Jan 1, 2017

By T. T. Matuludi

Kleinkopje Colliery has five Wemco drums that were installed and commissioned in 1978. Over the years, there have been remarkable changes in mining and geological conditions at the colliery. First, an increase in the percentage of fines was recorded, which resulted in an uneven split or an imbalance in silo levels between material feeding the cyclone (-12 mm) and Wemco drum (+12 mm) sections respectively. This problem was solved by doing modifications around the banana screens to allow finer material to the drums. The imbalance challenge was then followed by spontaneous combustion that takes place in situ and results in low product yield. The results obtained from efficiency tests indicate that although there is a limit in the percentage of -6 mm material in the feed, Wemco drums are still very efficient and applicable to the current mining conditions. These results also suggest that it is essential to lower the throughput when the drums are treating low yielding coal.

Jan 1, 2010

By C. Clark, P. Patton, B. M. Stewart

Handling materials in underground mines continues to be a major safety problem. To help reduce materials-handling injuries, the National Institute for Occupational Safety and Health (NIOSH) at the Spokane Research Laboratory is developing, modifying, and testing equipment to replace the necessity of doing lifting tasks manually. To reduce single-event lift injuries, equipment having mechanical automatic weight sensing and balancing control was investigated. The Coleman manipulator was selected for testing. Modifications to the Coleman manipulator to make it more suitable for underground mine use included mobilization, self-containment, all-purpose gripper attachment, and support jacks. To reduce or eliminate the need to clean off manually the materials that commonly plug grizzly openings (timbers, wire mesh, roof bolts, and other debris), a track-guided pincher arm device was developed. The TGPA attaches to an impact hammer head, and the pincher arms are controlled by the operator of the hammer. Oversized rock can be broken with the pincher arms in the up position; the arms can then be lowered to grab and remove debris. Sweeping action to remove cohesive fines bridging grizzly openings is also greatly improved. This device is especially useful in recessed grizzlies. An industrial gun was tested to evaluate its effectiveness in breaking oversized rock. Boulders up to 76 cm in diameter were successfully broken to minus 33 cm. Although methods to control flyrock need to be developed, an industrial gun may be a safe and inexpensive alternative to breaking oversized rock in certain underground mining situations. Keywords: Mining, materials handling, over-exertion, injuries

Sep 1, 2001

By N. C. Joughin

A simplified economic model is derived for the financial return from a new gold mining project. The model is used to analyze the effects of changes in the mining rate, capital costs, working costs, value of the reef and the stoping width. The most effective avenues for improving the return from a new project are indicated. It is shown that those technological innovations which would improve the return significantly, and therefore make it possible to open more mines, are the use of smaller mines, means for improving the mining rate to capital costs ratio for smaller mines, planning and control of mines by computer simulation, an improved mine valuation procedure and means for mining at a decreased stope tramming width.

Jan 1, 2014

By M. du Toit

Cromanite?is a new high-strength austenitic stainless steel developed by Columbus Stainless. It contains approximately 19 percent chromium, 10 per cent manganese and 0,5 per cent nitrogen. Cromanite can be welded successfully, but due to the high nitrogen content of the base metal, certain precautions have to be taken to ensure sound welds with the desired combination of properties. Although no matching filler metals are currently available, Cromanite can be welded using a range of commercially available stainless steel welding consumables. Welds produced using E309L, E307, E307Si and E312 filler wires are resistant to hot cracking and the formation of nitrogen-induced porosity, but the hardness, strength, ductility and toughness of the welds are generally inferior to those of the base metal. In applications where full use is made of Cromanite?s high strength, welds with matching strength levels would be required. In wear applications, where Cromanite is used primarily for its work-hardening properties and corrosion resistance, lower strength welds would probably be acceptable. Welds produced using E307 filler metal demonstrate the best combination of properties for use in wear applications. The welds display high rates of work-hardening that would result in increases in hardness and strength when subjected to abrasive or high impact environments.

Jan 1, 1999

By S. J. Moema, M. G. Maruma, L. A. Mampuru, M. E. Maja

"The most commonly used high-chromium white cast iron (HCWCI) is the hypoeutectic white cast iron that contains 2–3.5 wt.% C and 10–30% Cr. This type of material relies on hard, brittle M7C3 carbides to impart good wear resistance. Due to its good wear resistance, this material has found application in the mining industry and cement industry. However, it has low fracture strength and this challenge led to research aimed at refining the microstructure. This was done by the addition of niobium in the range between 0.1 and 0.6 wt.%. In the as-cast condition, the addition of niobium was found to increase the fracture strength due to the finer eutectic microstructure. The hardness was also found to have increased slightly compared to the reference alloy with no niobium additions. Low fracture strength after heat treatment was observed in the Nb-added HCWCI, which is believed to have been caused by the precipitation of secondary carbides and the transformation of the matrix from austenite to martensitic. IntroductionFor the past few years Mintek has been involved in a project in which a number of alloys have been identified for grinding media applications. The high-chromium white cast iron (HCWCI) alloys were among the alloys researched for this application. The knowledge acquired from the grinding ball media research has now been extended to mill liners, which have traditionally been made of manganese-, chromium- and chrome-molybdenum steels. The replacement of worn mill liners costs the mining industry a significant amount of money and this has led to a need for continuous research to prolong the life of the liners. During milling operations, liner wear has an adverse effect on the capacity of the mill, the energy efficiency and milling efficiency and finally leads to relining, to replace worn liners."

Jan 1, 2016

By S. Sinha, S. Ganguly

"In an opencast mine explosives are used for fragmentation of rock. Inefficient use of explosive energy in an opencast operation produces excessive ground vibration, which is measured by peak particle velocity (PPV). To mitigate ground vibration, it is essential to develop a model to predict PPV. At present empirical models are used. These models are based on only a few input variables, hence they fail to take into account the effects of the myriad factors that cause ground vibration. Due to lack of explicit knowledge about the complex mine blasting system the scope of application of mathematical and statistical modeling techniques is limited. The artificial neural network (ANN) technique is a learning algorithm that can remove some of these limitations and can be applied to predict PPV. In this paper an ANN model is developed for prediction of blast vibration using 248 data records collected from three coal mines with diverse geomining conditions. The correlation coefficient between measured PPV and model output was found to be 0.96 and the average error percentage 11.85. The ANN model output was compared with the output of three empirical models that are widely used for prediction of PPV. The correlation coefficient between the PPV predicted by an empirical model and measured PPV data was 0.63 and the relative error percentage 38.47. This result demonstrates the superiority of the ANN model compared to empirical blast models. By using site-specific structural discontinuities as input the model performance can be further improved. Sensitivity analysis and 3D plotting were used to gain further knowledge about blast-induced ground vibration. IntroductionIn an opencast coal mine explosives are used for fragmentation of coal and overburden. If the explosive energy is not fully utilized it causes blast-induced ground vibration, which may damage nearby structures. Ground vibration is expressed as peak particle velocity (PPV). During different stages of mine planning and operation, it is necessary to use a ground vibration prediction model for blasthole design. Selection of the modelling technique is crucial. Mathematical and statistical modelling techniques have limited application because of the lack of explicit knowledge about the complex mine blasting system. Vogiatzi (2002) highlighted the problem of multicollinearity in case of statistical modeling techniques. Mutalib et al. (2013) stated that mathematical models are unable to capture the nonlinear relationship between several blasting-related parameters due to the complexity of the model input data. However, the difficulty involved in modelling complex blast vibration problems can be removed by adopting an alternative soft computing modelling approach. One of the soft computing techniques is the artificial neural network (ANN). Ragam and Nimaje (2018) developed an ANN model for predicting PPV using six input variables. Kosti et al. (2013) stated that the conventional predictors fail to provide acceptable prediction accuracy. They showed that a neural network model with four mine blast parameters as input could make significantly more accurate on-site predictions. Sayadi et al., (2013), using a database from Teheran Cement Company limestone mines, found that a neural network resulted in maximum accuracy and minimum error. Khandelwal and Singh (2009) developed an ANN model using 150 data records from an Indian coal mine with site-specific rock characteristics and geomining setting. Khandewal and Singh (2007) built a ground vibration prediction model for a magnesite mine using four prediction variables with 20 data records. Kamali and Ataei (2010) predicted PPV in the structure of the Karoun III power plant and dam using an ANN. El Hafiz et al. (2010) evaluated ground vibration predictors using data from a single-station seismograph at a limestone quarry in Egypt."

Feb 1, 2019

By R. C. D. Phillis

Conventional stoping in hard rock mining is largely considered an operational environment. This paper suggests that stoping falls within the realm of a project management environment typified by uncertainty, variation, and large numbers of interdependencies. Stoping was then equated to a micro-project with many simultaneous activities that had to be executed accurately using finite resources within limited shift durations in order to reach specific goals. Critical chain project management (CCPM) principles were applied to the stoping activities, and the results showed that the number of blasts per panel can be significantly increased by successfully moving the distribution of work as close as possible to the start of shift. Critical chain principles also assisted in facilitating re-focusing and teamwork among stoping crews as well as between day- and night-shift crews. The main recorded success was in managing inherent protective capacities/local contingencies/fat/buffers that are found in all projects. The impact on mine health and safety (MHS) was significant as individual operators and crews became convinced that they could perform all stoping tasks (activities) without compromising accuracy or speed.

Jan 1, 2011

By W. Bleloch

In the process described, hydrogen is used to generate high-temperature steam and oxygen in the molten bath. Steel is decarburized to low levels to produce a pearlite-free steel suitable for deep drawing. The process makes use of the favourable thermodynamics in the reactions between steam, carbon, and iron, as well as providing high-temperature oxygen for the decarburizing reaction. The process can easily be incorporated in existing BOF (basic oxygen furnace) plant but can also be contemplated as a greenfield process.

Jan 1, 1987

By P. Smit

Health hazards of South African . mIne water by P. SMIT, M.B., Ch.B., D.T.M.H., D.P.H. (Visitor) The water supply in South African mines is not as good as most mining engineers would like to believe, nor is sufficient care taken to ensure the safe dispensing, transportation, and consumption of water. As long as cases of dysentery and typhoid continue to occur in large numbers, it can be assumed only that the water supplies are not safe, or that the water-dispensing methods are poor. A dual water supply is a real health hazard. The ideal water supply is a single safe source for human consumption and industrial use.

Jan 4, 1977

By P Knight, P A. Walker, H E. Speight

Pushback 8 South is the final cut back on the south wall of the East Pit at BHPBilliton?s Mt Whaleback iron ore mine in the Pilbara region of Western Australia. Development of the cutback commenced in 1999 and is now nearing completion with ultimate pit walls up to 300m high. This paper describes the geotechnical, structural and hydrogeological setting of PB8S, reconciliation between design and slope performance and the slope engineering techniques used to effectively manage the risks associated with the slope. These techniques include slope buttressing and sequential mining with waste backfilling, as well as a detailed program of displacement and hydrogeological monitoring, structural mapping and slope stability assessment. During the course of slope formation recent developments in remote slope displacement monitoring using radar and remote structural mapping using terrestrial photogrammetry have also been applied. Aspects of the PB8S slope management plan are relevant to many large scale open pit slopes. This paper provides geotechnical practitioners with information which may be helpful in managing geotechnical risk in similar environments.

Jan 1, 2006