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By J Boland

Polycrystalline diamond compacts (PDC) have been widely used as cutting elements in the drilling tools for the oil, gas, civil and mining industries because of their faster penetration rates and longer bit life. US Department of Energy reports that PDC bits account for more than one-third of the total footage drilled worldwide (US Department of Energy, 2004). However, non-thermally-stable diamond composites (NTSDC) have seldom been applied to geothermal drilling, since premature failures of such PDC cutters have been observed in hard rock formations. Several factors need to be considered to prevent premature failure of cutters and improve cutting performance when using PDC-based bits and other rock cutting tools. The first set of factors consists of the strength, density, stiffness, toughness and thermal resistance of the PDC and the rock. A second set relates to the complex behaviour of the bonding between the PDC cutter and the bit matrix, or the pick and the pick holder, which is vital in maintaining stable, reliable and durable adhesion of the cutters to their hubs. Finally, based on a better understanding of the cutting processes, the formulation of a predictive model would assist in further development of cutter design.

Jan 1, 2004

In dense medium processes for the beneficiation of minerals the consumption of medium (generally ferrosilicon) represents a major component of the operating cost. This provides a strong incentive for improvements in heavy medium recovery circuit design and operation. A major thrust in heavy medium plant design over the past decade has therefore been towards circuits which reduce medium losses. In this paper recent trends in plant design are examined in relation to the factors infl uencing circuit performance and medium losses. Operational details ' which have a significant effect on losses are discussed and illustrated by means of plant and pilot plant test data, with particular emphasis on the performance of wet drum magnetic separators. While the emphasis is on reducing the consumption of the high-cost ferrosilicon medium used in minerals beneficiation, most of the principles described in this paper are equally relevant to the design and operation of magnetite recovery circuits for coal preparation plants.

Jan 1, 1987

By Beer G

The recent re-emergence of an Integral Pressure Stripping system which operates with both cell and column in closed circuit at elevated temperature and pressure, requires no cyanide in the eluate solution and has greatly reduced carbon reactivation requirements in seen as a progressive step in this area. Several of these re-configured IPS systems have been placed in service in Australia and overseas in the last three years, with the first of the new generation units constructed and commissioned by Como Engineers Pty. Ltd. at Mt. Fisher in the East Murchison of W.A. in September 1987. This plant was relocated to a new ore body at Darlot W.A. in February 1989. Use is made of a data base of raw plant performance figures from both Mr. Fisher and Darlot and its performance compared with other operating plants. Initial commissioning difficulties of the Mt. Fisher prototype and dis- cussed together with the modifications and operational procedures required to overcome these problems. Stripping times of less than 6 hours at 145 degrees have been achieved with barren carbon values less than l O ppm from loaded carbon values above 3000 ppm and with cell pass efficiencies reaching 90 per cent.

Jan 1, 1991

The occurence of high silver values in the oxidised zone of the main lode at Broken Hill is well known as a large factor in achieving the early fame of Broken Hill, and the minerals of this zone form a long list, which has been tabulated by G Smith*, and includes...

Jan 1, 1926

This problem is seen as being central to a number of peripheral problems. Of these, the following are considered to be of major importance: 1. Reserves. Changes in Quality. Depths at which they occur. The effects of catchment and water storage areas. The effects of urban development. 2. Environment and the compat- ibility of mining and preparation of coal. 3. Transportation of Coal. J. tabour.

Jan 1, 1976

This presentation addresses the sources and weighting of project risk in coarse gold deposits with relevance to experiences at the Ballarat mine and Castlemaine goldfield. With sample representation and reliability often a source of great error in the resource estimation of coarse gold deposits, it follows that this matter should be of greatest risk to a mining project - but is it? What are the costs and efforts required to best quantify the sampling error due to nuggetty effect? After all, the main problem in Victorian gold mining ventures in the current decade is not the amount of gold available, but defi ning which portion of it can be converted to Ore Reserves or more so profitable gold bars. The author postulates that greater risk to the project lies in the geological interpretation and matching resource spatial parameters to mining methods, than the degree of uncertainty related to grade due to nuggetty gold. Recent experience in the Victorian goldfi elds is that the investor market has already severely discounted Mineral Resources reported in accordance with The JORC Code - so if they don't believe in the capacity to upgrade the resource why should we? To this end, Castlemaine Goldfi elds Ltd at its Ballarat gold project does not intend to estimate its gold mineralisation for public release, instead choosing to focus on the geological interpretation and mine planning elements. So with coarse gold deposits, is your Mineral Resource reported with The JORC Code a glass half full or half empty? Our mining forefathers in Victoria had no predictive tools which could define resources to any degree and yet were successful. By over emphasis on the definition of mineral resources and particularly the sampling error, are we ignoring the basics of cost control, solid geological interpretations and maximum mining flexibility. This is an ABSTRACT ONLY. No paper was prepared for this presentation.

Aug 1, 2010

By Wright R. J

The Commission called tenders for a four boom hydraulic jumbo, plus basket, on an art- iculated carrier in Sept. 1977. Atlas Copco submitted the successful tender in Jan. 1978 for the supply of a three boom jumbo, plus basket. The Promec TH470 jumbo was commiss- ioned in the 2000 m long Sophia tunnel in Nov. 1978. Adequate spare parts were not available during the first three months of operation and the hammers could not be overhauled at the recommended interval. One hammer was removed after drilling 13 600 m due to a crack in the intermediate housing. Tests were conducted with different types of drilling consumables. Both rope and Hi-teed threads were tested and found compar- able. The average penetration rate in the granite was 1.1 m/min. Initially the drillers were not experienced enough to operate the BUT 15ERH booms without causing damage to the booms and hoses. Drilling deviation espec- ially of the perimeter holes was greater than expected. It is now obvious that greater attention must be given to attracting, train- ing and retaining the right type of operator and maintenance fitter.

Jan 1, 1981

By A Manzoori, M T. Shadloo

This paper describes a CFD modelling study which was carried out to investigate possible improvements in the design of an alumina precipitator tank at the Jajarm plant of Iran Alumina Company. In particular, the tank has an impeller located very close to the tank bottom, such that it quickly becomes covered with settled solids after a shut-down of the agitator, making it difficult to restart. A CFD model was firstly set up in which the existing design was evaluated in terms of flow pattern, off-bottom suspension and distribution of solids, and power consumption. Further simulations were then carried out to test alternative designs, leading to a recommended design, which maintains good mixing, with the same power consumption and without the use of a low-clearance impeller.

Jan 1, 2006

In 1939 Dr Neil George gave us the statement: Safety is a state of mind by which men are constantly made aware of the possibility of injury at all times. Is this statement still relevant? Have we been able to capture the essence of Dr GeorgeÆs statement in our current safety management systems and have we been able to capture the lessons from the past? Drawing upon 25 years of experience in the mining industry we explore what was done in the past, how this related to Dr GeorgeÆs statement and how the industry has progressed to the current safety management systems. We review the safety management system used by Roche Mining and demonstrate how it has improved safety outcomes for Roche. We then look to the future û are there new challenges? Are the current management systems equipped to cater for these new challenges and deliver continued improvement in safety outcomes? There will always be a desire to improve the industryÆs safety outcomes and so how are future generations going to achieve the improvement in safety outcomes?

Jan 1, 2007

By Ruston R

When coal mining first commenced in Australia, the principle objective was low cost production with development directed toward recovery of 'easy' coal. Future expans- ion of these early mines into major under- ground operations was neither envisaged nor planned. As the demand for coal grew, these mines were expanded to increase output. however, the absence of initial ventilation planning brought about ad hoc systems wh;ch required continual repair and upgrading. These systems proved satisfactory in the short term because the majority of undergrouni coal mining operations were carried out at relatively shallow depths where gas emission rates were low. By comparison, coal is now being won at depths exceeding 500 metres with a corresponding increase in gas flow from the working seams and adjacent strata. The following paper addresses, firstly, the planning and institution of a ventilation system in a mine where previous inefficiencies were many, and secondly, the value of pre- planning a mine ventilation system in the early stages of mine development, and the need to continually review and upgrade the plan to account for unforeseen ^hanges.

Jan 1, 1983

By Carter NB

A statistically-designed experimental program has been used to study compositional and processing variables which influence the development of strength and reducibility of iron ore pellets. The effects of chemical composition and processing variables were investigated by indurating laboratory-made green pellets, of known composition, under approximately isothermal conditions in a pot- grate simulator. Some findings from a six- variable study are summarized in the form of contour diagrams and emphasize the importance of interactions between the variables. Production of strong, highly reducible pellets is possible over a considerable range of combinations of temperature and firing time. Abrasion index (AI) and cold compression strength (CCS) improve as both these variables increase, but reducibility (R) declines, so a compromise is required. When the lime level is too low to form enough slag for bonding, the AI and CCS may be inadequate. Larger additions of lime tend to improve AI and CCS, with only slight effects on R. Finer grinding of the balling feed (i.e. higher Blaine index) tends to improve Al and CCS without

Jan 1, 1980

By P Pieterse

Kumba Iron Ore Ltd is currently commissioning the Sishen Expansion Project (SEP) û a brownfields project on the Sishen Iron Ore Mine located in the Northern Cape Province, South Africa. SEP is designed to produce 13 Mtpa of product from 21.7 Mtpa of ROM feed. The beneficiation section of SEP employs jigs to process narrow size fractions in the 25 x 0.8 mm size range. The -0.8 mm fraction is screened out ahead of the jig plant and rejected as waste without any prior beneficiation. The processing of this fraction was not included in the early stages of SEP development because no suitable beneficiation or dewatering technologies could be identified within the time-frame required to implement SEP. This paper presents the SEP 1B project, ie the metallurgical and process engineering study that was done to evaluate the techno-economic viability of processing the -0.8 mm material of SEP. To support this evaluation, metallurgical bench scale testwork was done on selected samples characterising the material types used in the SEP for gravity concentration beneficiation. Subsequently, pilot testwork on a 300-ton bulk sample demonstrated that an integrated teeter-bed/spiral circuit could be used to successfully beneficiate the -0.8 mm fraction. The study has established the viability of the proposed process and has concluded that approximately 390 000 tpa could be produced and added to the SEP fine ore product without violating the applicable product specifications. The proposed process has been designed to be implemented in modular units in order to facilitate implementation and ensure future expandability. Based on the recommendations of the study, approval has been granted for the detail design feasibility study. Production is scheduled to commence in the first quarter of 2010.

Jan 1, 2008

Discontinuities often have a very detrimental effect on the stability of mine highwall faces. The west wall of the Muja open cut is remarkable for the number and variety of discontinuity sets which occur over a relatively small area. To-date 14 separate structural domains have been identified over an area measuring approximately 560 m by 120 m.The structural domains have been grouped into four structural assemblages on the basis of their angular relationships to each other and to regional folding and faulting. The distribution of these structural assemblages appears to be erratic and no controlling factors have been identified to explain or predict them other than in the most generalised terms.

Jan 1, 1993

Variety among deserts is nearly as great as among other climatic environments. Common to most deserts, and to areas downwind from them, is the dominance of aeolian transport of surface material, at least during some seasons of the year. The result is dilution of local surface materials with varying proportions of chemically uniform fine sand and silt, often imported by the wind from remote areas. Fortunately, desert pavement,.even though separated from bedrock by a meter or more of nearly pure loess, is simply a diluted reflection of nearby bedrock. Infiltration of loess through the surface debris and the rudimentary soil-forming processes in the desert usually preserve the integrity of the pavement. This pavement, or its "downstream" derivatives, provides a suitable sample for exploration geochemistry if proper care is taken to circumvent the aeolian dilution. The simplest and most commonly used method of circumventing the dilution is to use a coarse fraction of soils or stream sediments, discarding or retaining the finer fraction depending upon the magnitude of the dilution. Where the coarse surface debris is composed of rock chips representative of the bedrock sources, the method is successful. Under most circumstances the coarse fraction of the surface material will give a fair representation of gross lithology and will occasionally give an indication of mineral- ization. The major drawback to this approach is that selective weathering and erosion in the vicinity of mineral deposits often lead to the loss of ore minerals into the finer fraction, leaving a coarse residue enriched in feldspar and particularly in quartz; thus, the geochemical signature from a mineral deposit is effectively reduced or completely masked. The second most commonly used method to overcome aeolian dilution, and probably the most effective at present, is to use a heavy- mineral concentrate. This approach presupposes that the chemical signature sought resides in a heavy mineral. Fortunately, the arid weathering cycle is conducive to the formation of a wide variety of secondary ore

Jan 1, 1988

By Treglown N

In any mining operation the curtailment of rising operating costs is of prime concern to management.One area of activity where costs are often disguised is that of longhole secondary breakage.This paper outlines sane operational techniques that have been considered and tested, resulting in improved fragmentation fran longhole stope blasts at New Broken Hill Consolidated Limited mine, Broken Hill, NSW.

Jan 1, 1985

The Key Issues - An Overview Minerals industry needs Mining companies want technologies which are ò cost-effective, ò high likelihood of delivery (ie transfer existing technologies from other industries), ò highly useable, ò an evolutionary rather than revolutionary approach, and ò to be developed in partnership with the mine, supply groups and researchers, For example, `soft' systems for information collection to better manage the mining process rather than mechanical systems.

Jan 1, 1997

By Russell F. M

Following the accident in the Peterson section of Mufulira mine in September, 1970, a method had to be found of extracting up to 300 000 tonnes of ore per month from this area without inducing caving. Sandfill mining methods were chosen, necessitating a plant capable of producing both cemented and uncemented fill on a large scale. The paper covers the design and construction of this sandplant which is thought to be unique for its size, as it incorporates three 3 000 tonne capacity settled storage silos, a 500 tonne capacity cement silo, mixing tanks and a control room situated underground. The plant is designed to handle an aver- age of 440 tonnes per hour with a maximum of 660 tonnes per hour for limited periods, delivering either uncemented fill or cemented fill in proportions varying from 1:6 to 1:30. The instrumentation and equipment necessary to give one man operation of the plant is described and the fill mining methods now in use at Mufulira are briefly outlined.

Jan 1, 1973

By Bearman R. A

The majority of published material regarding the operation of crushing machinery is concerned with simulation of performance rather than design of equipment. The reason underlying the bias in published material relates to why research is carried out and who undertakes the research. Two distinct types of research can be identified: 1. Internal research by crusher manufacturers - generally related to mechanical design, value engineering and to the commercial realities attached to sales demands. Any work on basic crusher geometry or rock/machine interaction is of a sensitive nature and rarely enters the public domain. 2. Academic research - mostly confined to modelling of crusher performance and simulation. This is not because of any bias, but crusher design requires access to manufacturers data or at least an in-depth understanding of crusher design, which is rarely available. The crushing of rock is a complicated problem. It involves three aspects; the machine geometry, the material composition (type of rock/feed size distribution) and the machine/rock interaction. The machine geometry is often ignored in empirical mineral processing simulations, while the response of different feed materials is only nominally addressed in machine specifications provided by manufacturers. The manner by which the machine produces a stress field and causes different types of breakage for different rocks (or the machine/rock interaction) is sadly neglected by both groups. All three aspects must be considered collectively to successfully understand and model the entire crushing process. 1. Centre for Mining Technology and Equipment, Julius Kruttschnitt Mineral Research Centre, University of Queensland, Isles Road, Indooroopilly 4068 Qld. The importance of crushing is often underestimated. In mining and mineral processing the invisibility of the crushing process is understandable as it merely provides a coarse reduction stage prior to the intricacies of mineral extraction. However in the quarrying industry crushing and screening basically provide the finished product. A brief overview of the quarrying industry shows the importance of crushing. Figure 1 gives production figures for most of the western European countries, Australia and the USA.

Jan 1, 1995

The Rosebery Mine on the west coast of Tasmania is a world class polymetallic base metal deposit, containing six major minerals: galena, sphalerite, chalcopyrite, gold, silver and pyrite. This resource has been exploited for nearly a century, yet a reliable estimate of the reserve continues to present a challenge.Over the past twenty years, the operation has changed from relatively low productivity cut and fill timber-support scraper mining, to higher productivity bulk mechanised open stoping. At the same time, economic constraints have changed and grades have fallen, which have increased the pressure to refine the resource/reserve estimating processes. This paper compares the restrictions of the polygonal section method of the past with the advantages of a kriged block model. The limitations of Mine Call Factors, the problems involved in converting decades of diamond drilling data on paper into a computer data base, and the effect of this new methodology at Rosebery, are described.

Jan 1, 1990

Physical model testing at Bergbauforschung is done in two rigs, a roadway rig and a longwall rig. The loading of such models, in scale relation to the con- ditions in the collieries provides valuable guidance to the probability and nature of failures, and thus to support requirements, in structural, roofbolts and self- auvancing supports. The success of such modelling when related to subsequent underground designs put to use suggests that such methods of investigation could be extended to pillar extraction problems also.

Jan 1, 1974