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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

By A Baensch, E Grimsley

Eloise Copper Mine is situated 56 km east-southeast of Cloncurry, Queensland, Australia. The deposit was discovered by BHP Minerals in 1986 during follow up diamond drilling of EM anomalies associated with major aeromagnetic anomalies. The deposit is overlain by 60 m of Mesozoic cover. Amalg Resources NL commenced mining during 1995 by means of decline access and long hole-stoping. The total mineral resource comprised 1.77 million tonnes at 4.10 per cent Cu as at the end of June 2003. Proved and probable reserves are 930 000 tonnes at 3.97 per cent Cu. Mineralisation is hosted within a strongly foliated Proterozoic meta-sedimentary sequence comprising arenites and schists. The metasediment sequence also contains a coarse-grained amphibolite body possibly representing an early intrusion of gabbroic composition. Economic mineralisation characteristically occurs as a number of steeply plunging lenticular bodies with strike lengths of between 100 and 200 m and maximum widths approaching 25 m. The principal orebody, the Levuka (B) Lode, displays a down plunge extension exceeding 1000 m and is open at depth. Ore mineralogy is almost exclusively chalcopyrite with the principal gangue phases consisting of pyrrhotite + quartz + carbonate. A biotite + hornblende + magnetite assemblage represents locally intense mafic alteration of the metasedimentary host sequence. Magnetite is present in variable amounts and may be locally significant in some of the smaller satellite orebodies. Within the orebodies the sulfides display a range of textures from massive through to vein like. Sulfides commonly display brecciated textures at a range of scales. Post-mineralisation faulting has severely dislocated the orebodies, resulting in a complex arrangement of fault bounded ore blocks. These faults display considerable variability in regard to strike, dip and amount and direction of throw. A recent review of the fault system by means of large-scale structure underground mapping, re-interpretation of drill core and 3D modelling has led to a significant improvement in the understanding of these structures. A significant upgrade of the geological database has accompanied the structural review. The overall improved understanding has aided the mine design processes with particular regard to decline and access development and pillar location. This has also impacted on the design of drilling programs and exploration for additional satellite ore zones.

Jan 1, 2003

There is a Chinese saying-may you live in interesting times. Certainly we do tod.a~our mining professions. We are, of course, totally dependent on a' healthy mining industry for the chance to practice our chosen professions, and for our Institute.Let us look at one of the more interesting facts. The mining industry now accounts for some 50 per cent of Australia's exports.This massive earning of foreign exchange is the key to keeping our increasing overseas debt in check. Furthermore, mineral production..including petroleum, saves us a large amount of foreign currency by providing essential minerals, including energy minerals, for local consumption.With such fundamental inputs to our economy, any primary school student, any child in fact, should be able to see that the mining industry and mining professions are very important to our nation. Yet the average citizen is unaware of this simple fact as they enjoy their high standard'of living and think that we are still living in the lucky country.Therefore, it is most interesting to me that the average citizen, and most of our politicians, seem to hold mining and miners in low esteem. I use the term miners to describe all those important people, like us, who work in the mining professions, and are employed by, or are dependent on, the mining industry.So why are we miners in this paradoxical situation of doing wonderful works, being the backbone of the country, and yet being held in low regard by the very community we underwrite.Truly-it is interesting-or did the Chinese mean intriguing?It is indeed paradoxical that we are the rare people who open up the land, borrow small parts of it for a relatively short time to harvest the mineral crops, then return it to the community for other uses; and when we return the land back to the community at large it should be in better shape than when we started. There will be infrastructure - roads, airstrips, supplies of water and power, parks and housing-all left behind after mining.These benefits to the community are ignored while our critics focus on the small scars on the landscape which sometimes cannot be healed at reasonable cost; and yet, if we allow time, nature usually heals the small scars anyway. Look at New Zealand, particularly the Coromandel Peninsula which was intensively mined and logged; now it is covered with secondary growth and stark pine plantations. Remember that mining scars are infinitesimally small when compared to urban sprawl or clearing of land for farming and grazing, or highways, or the area of most national parks.Thus, miners are important citizens economically, and we are the majority of the few who actually practice the principles of multiple land use.What are the consequences of our image? They are serious in that the poor image we seem to project, discourages many people from becoming involved in, or supportive of, our industry. This brings me to my theme for the year: Students, Education and Communication - the Key to our Future.

Jan 1, 1987

By Favreau RF

Over the last 20 years the blasting industry has progressed from the stage of being artform to a science as it is today. The use of computers to simulate blasting results has allowed blasting engineers to accurately pre- dict blast results and to optimise their blasting. This paper describes the computer blast simulator called BLASPA and its various applications in blasting. BLASPA allows the blasting engineer to predict blast results given known details of explosive properties, their distribution, rock type and properties, hole size, burden, spacing, collar and subdrill. The simulator runs mathematical situations and outputs numerical estimates of fragmentation and muckpile results. The paper discusses results which show that the mathematical outputs correlate very closely with actual results seen in the field, thus confirming the validity of the simulator. BLASPA can be used to help improve blast design by predicting stress levels in the rock mass and consequent rock breakage.

Jan 1, 1986

By Bayly MG, Harris JA

The current operational practice at the Territory Enterprises Pty, Limited uranium oxide plant,, and some aspects of researc$ and development work at Rum Jungle are outlined with pertinent comments on some overseas practices.

Jan 1, 1968

Longhole stope overbreak has always been a source of unwanted cost within the underground mining industry, and efforts to control it using various rock reinforcement systems have long been a rock engineering challenge. At the Pasminco Mining Broken Hill Operations trials have been carried out using an innovative cable bolt reinforcement system known as Rib-Roc. The system, based loosely on the Swedish Rib-in-Roc concept, utilises zones or ribs of heavily reinforced rock in the troublesome hangingwall and back areas of longhole stoping. The trials were carried out under a strict qualitative and quantitative scientific stope measurement program utilising rock mechanics instrumentation. Not only did the trial demonstrate the success of the system but data obtained was useful in implementing the system virtually as standard practice throughout the operation.

Jan 1, 1995

By C Morley, B Costello

In 2002 the Argyle Diamond Mine upgraded the process plantÆs recrush circuit to include a High Pressure Grinding Roll (HPGR), or High Pressure Rolls Crushers (HPRC) as they are termed in the diamond industry. HPGR have generated considerable interest over the last decade, though there are still technical/processing unknowns to its effectiveness as a primary diamond ore crusher.The upgrade of the Recrush circuit at Argyle Diamonds has gone a long way to answering some of the key questions, and thus it has reduced the unknowns to a level more acceptable to the industry.This paper focuses on the results from the HPRC at Argyle, in particular the performance of the studded wear surfaces, comparison of energy efficiency against traditional quaternary cone crushers and the resultant increased liberation. Issues that have arisen, including edge wear of the studded surfaces, will be discussed and the steps taken to reduce this issue are presented.

Jan 1, 2004

By Miyashita T, Yamamoto R, Kishimoto s

Following considerations of the effect of furnace size on pressure loss, pressure loss in front of tuyeres, gas flow in the lower parts of the furnace, the distribution of the burden and the gas flow in large blast furnaces is examined with particular reference to the burden distribution at the throat and the gas flow at high production rates. Improvement of gas flow is related to application of super-high top pressure and the use of moveable armour. A brief description of the NKK type moveable armour is given and its use in controlling the gas flow outlined. The operating results under controlled gas flow show an increase in production of Fukuyama No. 5 BF from 9,200 tpd to 11,000 tpd with a decrease in the fuel rate from 490 kg/thm to 460 kg/thm.

Jan 1, 1975

By Morrison R. S, Doennilan N

Recent mapping (1989-1992) by the Northern Territory Geological Survey in the Tennant Creek 1:250 000 map sheet area has resulted in substantial revision of the lithostratigraphy of the Tennant Creek Block (Donnellan, Hussey, and Morrison, in press). Briefly, the former Warramunga Group (Dunnet and Harding, 1967; Dodson and Gardener, 1978) is divided into the Warramunga Formation, and an overlying less deformed volcano-sedimentary succession, the Flynn Subgroup. The latter is conformably overlain by the Tomkinson Creek Subgroup of the Tomkinson Creek province in the north of the Tennant Creek Inlier. These two Subgroups constitute the Churchills Head Group which is essentially equivalent to the Hatches Creek Group of the Davenport province to the south of the Inlier.

Jan 1, 1994

By Campbell Brown G A

IN 1904-5 diamond drilling operations in the Mount Morgan mine proved the presence of some millions of tons of rich copper-gold ore, averaging about 45%to 50%silica and 22%Fe as sulphide. To smelt this ore in blast furnaces, without previous concentration, large quantities of basic flux were required. Unlimited quantities of cheap limestone were available at Marmor, on the GladstoneRockhampton railway, 50 miles from Mount Morgan, but the supply of iron flux was a more difficult problem. Smelting Operations started with one furnace in January, 1906, using as flux low-grade sulphide ore from the mine, containing very little silica. When the second furnace was blown in this was supplemented by ironstone from small deposits in the immediate district. It was recognized that these sources of supply would be insufficient to keep the full plant going after the third furnace had been blown in. Accordingly, the deposits at Kabra and Mount Etna were opened, neither of which proved capable of supplying the quantity required-viz., 1000 tons per week. Negotiations were meanwhile being conducted with the Marble Island Iron and Limestone Co. to obtain the right to mine at Iron Island, where a sufficiently large deposit was known to exist. Shipments from this source commenced in January, 1907, and ceased at the end of July of this year, when the metallic flux from...

Jan 1, 1911

By Nava-Vasquez E, Torres-Torres J, Mendez-Nonell J

The ZA-27 zinc base alloy was poured into cylindrical moulds and solidified under different conditions ie normal freezing and unidirectional freezing. In addition a cylindrical ingot with rheocast material was obtained by stopping the stirring action and, at a specific solid fraction, gravity casting it into a graphite mould. It was observed that the material obtained under normal freezing conditions is likely to present both segregation and inverted pipe. In contrast, the unidirectional solidified and the rheocast cylinders showed the absence of inverted pipe. The segregation pattern was quite irregular in the rheocast ingot while such segregation was more uniform in the unidirectional solidified cylinder. By virtue of these observations, the inverted pipe formation may be ascribed to the interdendritic flow, while the irregular segregation pattern in the rheocast ingot may be attributed to an irregular distribution of the liquid and solid fraction along such a cylinder.

Jan 1, 1993

By Hamblyn S

Oakbridge, in combination with its joint venture partner, Nippon Steel of Japan, is expanding its Bulga underground and open cut mines to meet the growing demand for coal in the Asian market. Expansion works underway will see the Bulga underground mine become a world leader in underground productivity, the introduction of a high capacity dragline into the open cut mine (largest capacity dragline in NSW) as well as a major upgrade of the coal preparation plant (CPP) and coal handling facilities (CHF) to process the increased production. This paper describes the planning and implementation of this major expansion program and highlights the rationale behind some key aspects of the program.

Jan 1, 1995

By Sowerby BD

The CSIRU Division of Mineral Engineering is developing various techniques for the on-line determination of moisture in coal and coke, and some instruments are now commercially available. These techniques permit accurate and rapid determination of moisture in materials directly on conveyor belts or in bins. The most promising techniques for direct on-belt measurement of moisture in coal are capacitance and microwave transmission. A non-contacting under-belt capacitance and gamma-ray backscatter technique has determined moisture in coal to better than 0.5 wt'/. in field tests at BHP Stockton Borehole Colliery, NSW. Mineral Control Instrumentation Pty Ltd have been licensed to manufacture the capacitance gauges and have installed five commercial units in the coal industry and other industries. Microwave transmission techniques have an advantage over the under-belt capacitance technique in that they are not sensitive to vertical segregation of moisture in coal on the conveyor belt. A laboratory prototype of a microwave transmission gauge has been constructed and tested. Microwave techniques, based on a measurement of attenuation and phase shift, are under development and are expected to be field tested in 1987. These new techniques will enable a wide range of thickness changes to be accommodated. Capacitance and microwave transmission methods are unsuitable for materials of high electrical conductivity, such as coke. CSIRO is therefore developing a fast neutron and gamma-ray transmission technique, which is proving very accurate in laboratory tests. This technique overcomes many of the limitations of thermal neutron moisture gauges and it is expected to be field tested in 1987.

Jan 1, 1987

By Orr T. O H, Hodkinson I. P

The Mount Leyshon breccia complex is located on an east-west trending contact between Cambrian metasediments (Puddler Creek Formation) and the Ordovician Mt. Leyshon granite, within the Lolworth-Ravenswood block. Detailed mapping of basement, breccia and igneous unit geometries, crosscutting relationships and resolution of complex chronological relation- ships indicates that the Mt. Leyshon breccia complex should be reinterpreted as a number of intrusive igneous and breccia phases. This is in contrast to a previously published account of a largely extrusive geological setting. A complex structural history dominated by strike-slip faulting is preserved within the basement units and is responsible for controlling the location and geometry of the breccia complex. The breccia complex has been divided into brecciated "basement", "main pipe breccia" and an "interactive magma/breccia sequence". Main pipe breccia (the most voluminous unit within the complex) has been re-interpreted as an intrusive breccia, rather than an extrusive or vent fill as previously proposed. This is based on the following evidence: 1. the facies characteristics of the main pipe breccia, 2. the presence of a progression from cohesive basement through to mixed breccia, 3. minor basement block rotation during breccia complex formation, and 4. the partial structural control on the main pipe breccia. No unambiguous evidence exists for pyroclastic facies, although the fine breccia variant commonly contains "accretionary structures", very similar in appearance to those formed during pyroclastic processes. In view of 1. above, they are interpreted to be the product of particle accretion during upward movement of fragmental material, although an origin due to altera- tion cannot be completely discounted. heir occurrence in the main pipe breccia indicates that their presence within a rock unit is not necessarily diagnostic of nvroclastic nroeesses.

Jan 1, 1991

By Grano S. R, Ralston J

It is the perennial problem most metallurgists face when examining data collected from laboratory float tests and plant surveys - there are more numbers than we know what to do with! The objective of this paper is to analyse and interpret a set

Jan 1, 1994

Hidden under picturesque Bemic Lake, in Canada's eastern Manitoba, lies a highly fractionated pegmatite orebody, hosting a unique assemblage of minerals. Accidentally discovered in 1929, the orebody had a brief history as a tin producer, but it is now mined by Tantalum Mining Corporation of Canada, Ltd. (TANCO), for its cesium, lithium, rubidium and tantalum bearing minerals. The mine also has potential for mbidium-feldspar, amblygonite, gallium rich mica, and quartz production. This paper describes the geology of the orebody, and its mining and processing. Selective, concurrent, mining and milling of the various products necessitates a high degree of planning and control, and these aspects are also discussed. The introduction of Quality Control and SPC are discussed, for such are the keys to excellence.

Jan 1, 1989

A methodology for the fatigue life estimation of load haul dumpers, employed in underground platinum mines, has been developed and applied. This method entails the quantification of operating conditions by means of stress measurements. The measurements are then translated into a fatigue loading factor for a finite element model. The results of this analysis are then used to compare all the critical connections in the structure to detail categories in relevant fatigue codes, and predict a life in operating hours for the vehicle structure. The method was applied on a specific model and the results of this analysis were compared to actual failure occurrences with reasonable accuracy. It is intended that the methodology be embedded into performance specifications and purchasing contracts and that technology transfer to OEMs be achieved. Based on the experience of this project and other similar exercises it is estimated that structural life expectancies may be increased across a typical fleet of trackless mining vehicles (LHDs, drill rigs, utility vehicles, dump trucks) by at least 20 per cent.

Jan 1, 2005

Project Hobson involves the replacement of an existing 90-year-old above-ground sewer that crosses Hobson Bay in Auckland, New Zealand, and which is nearing the end of its economic life, with a 3 km long, 3.7 m internal diameter segmentally-lined bored tunnel. The $118 M project will offer several benefits to the owner, Watercare Services Ltd, and the local community:provide capacity to meet projected growth in the region,virtually eliminate wastewater overflows into Hobson Bay and the Waitemata Harbour, andremove an obtrusive visual feature and open up the bay for recreational purposes. The geology in the region is a sedimentary formation, which has been significantly influenced by volcanic activity; 49 volcanoes are present within 20 km of the nearby city centre. The geology along the alignment is dominated by two palaeovalleys which have been infilled with a combination of marine alluvium and volcanic deposits. Watercare Services Limited has elected to manage and share tunnelling risk through, among other key measures, the implementation of a geotechnical baseline report (GBR); one of the first uses of this type of document in Australasia. This paper describes the general principles behind the use of a GBR, the development of the GBR used in Project Hobson and some lessons learnt.

Jan 1, 2008

By M Wortley, A Cantarutti, T Ozkocak

The estimation of the grinding mill charge weight is vital to ensure its efficient performance. Mill underloading or overloading can cause losses through decreased production or unplanned down time. Metso Minerals Process Technology Asia Pacific and South America (MMPT) has developed two systems for measuring mill load. The first is an acoustic system (SmartEarÖ) and the second is an online model-based charge estimation system. The aim of both systems is to facilitate better operation of grinding mills. SmartEarÖ performs analysis on an audio signal from the mill and allows each different frequency component to be viewed, analysed and used in process control for load estimation. By isolating different frequencies, SmartEarÖ can give an estimate of mill load. The online dynamic mill model uses measurable mill parameters (such as power) to predict the current total load. Kalman filtering can also be utilised to further increase the accuracy of the model. Both of MetsoÆs systems have been installed at BHP BillitonÆs Cannington mine to measure the load within their autogenous (AG) mill. In this paper, the methods of mill load estimation are reviewed and compared to the bearing pressure reading, which is the current method used by Cannington to control mill load. The redundant estimates of mill load provide increased confidence and consequently more robust grinding operation under a wide range of conditions.

Jan 1, 2008

LESLIE BRADFORD GOLDEN JUBILEE ORATION "Not only a metallurgist but a scientist of the highest order" Leslie Bradford and the Australian Metallurgical Industry

Jan 1, 1987