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By Sullivan T. D

The Lochiel Deposit is a large occurrence of soft brown coal about 130 km north of Adelaide. The deposit is undergoing continued evalua- tion of which an integral part was the excavation of a Trial Pit. The Trial Pit was deemed necessary to demonstrate that the deposit may be mined efficiently by draglines and the particular emphasis was on the geotech- nical and hydrogeological aspects of what may be termed difficult mining conditions. The dewatering of the Trial Pit was commenced in September 1986. After considerable planning and excavation was successfully completed in May 1987. The project is unique in terms of its size and technical com- plexity. It entailed excavation of over 230,000 m3 of overburden to an overall depth of 36 metres. The excavated material was utilised for experimentation in a Trial Dump. Included in the Trial Pit design were several novel techniques includ- ing depressurisation drains to improve mining conditions in soil strength materials and the use of vacuum to aid dewatering.

Jan 1, 1988

By Richards BG, Komdeur W

Instability in spoil piles and in high wall slopes in natural overburden has been ex- perienced at Utah's Goonyella Mine since com- mencement of operations in early 1971. Annual production targets, although gener- ally met since the commencement of operations, required modifications to stripping and mining techniques and the rapid re-scheduling of oper- ations around unstable areas, but culminated in the earlier than planned acquisition of addit- ional stripping equipment. An understanding of failure mechanisms was developed within a collaborative study of pitwall instability between Utah Development Company and the C.S.I.R.O. Division of Applied Geomechanics. Results showed that pitwall instability occurs as structurally controlled deformations along planar failure surfaces; spoil pile failures are precipitated by moist- ure ingress and subsequent loss of strength of base layer materials; highwall failures de- velop over areally extensive bedding planes in conjunction with inclined and subvertical fractures caused by overburden blast damage.

Jan 1, 1978

By Harada M, Katsuta S

In order to shorten the time taken to com- plete shield tunnel excavation work, reduce labor costs and to improve safety, an automatic assembly robot system for the segments used has been developed. It was developed in the three years from 1982 until 1984. An experimental assembly system for concrete segments (outer diameter:.3.55m) has been thoroughly tested to confirm that these segments can be fed and assembled automatically (Fig. 1, 2). This report outlines the robot which will be put into practical use in the near future. The robot senses the position of already assem- bled segments by means of position sensors, controls the position and the attitude of the segment to be assembled to allow bolt hole positioning, and completes the automatic assembly of a se;nent by automatically tighten- ing bolts. The six segments which make up one ring can be automatically assembled in about 25 minutes.

Jan 1, 1987

Underground mine ventilation is now com monly simulated on a digital computer. Such a programme, incorporating natural ventilation has been modified by others to account for methane emission and elevated local tempera- tures. At Wollongong University, the pro- gramme was further developed and extensive interactive graphics incorporated such that any view of the three dimensional mine could be viewed, and superimposed upon that view are areas where a nominated parameter has exceeded a particular value - generally at a nominated time after a particular event and usually a fire/explosion of one type or another. A further programme was developed such that up to 20 'times' could be examined at a particu- lar location after say, a fuel rich fire at some other place in the mine. The output from this programme includes a plot of methane 1, smoke 1, temperature, pressure and air flow versus time - a most useful graphic to observe the limits of safe attendance in a particular Airway.

Jan 1, 1983

By Klenowski G, Gilmour G. A

The Metropolitan Water Supply, Sewerage and Drainage Board, Perth, has recently con- structed two major sewerage tunnels in the metropolitan area and a further one is under construction. These tunnels were constructed in sand, sandstone and limestone. The Tamala Limestone is a Pleistocene calcareous dune sand which now varies in com position from loose sand to cemented rock. Investigation techniques included surface mapping, auger and diamond core drilling, seismic refraction geophysics and mechanical testing. The variable nature of the ground caused difficulties in all aspects of the investigation, particularly in core recovery and seismic work. The Beenyup Tunnel, 2.25m in diameter and 3440m long was excavated with a Dosco TBM 1800 machine and shield with precast concrete Charcon Universal bolted segment lining. The Burns Beach Sewer Tunnel, 1.27m in diameter and 860m long was hand excavated with precast reinforced concrete lining pipes jacked continuously behind an excavation

Jan 1, 1981

The demands of the economy require larger manufacturing facilities using greater quantit- ies of raw materials which must be mined, handl- ed, stockpiled and recovered with efficiency and dependability. All over the world, mining com- panies, steel manufacturers, power stations and process plants are not only seeking but finding methods of increasing outputs and'reducing costs in the field of materials handling. In mining bigger continuous mining machines and shovels, larger trucks and crushers are digging and processing greater quantities of differing materials which have to be handled and shipped at rates once thought to be impossible. To implement such schemes demands the blending of a lot of diverse-equipment, mining machinery, bins, feeders, reclaimers and it is here that the belt conveyor assumes a role of ever increas- ing importance. Significant developments have taken place in the seventies with respect to conveyor belt transportation; not only in the systems but also in the components which combine to make such systems work efficiently.

Jan 1, 1976

Gold mining in Australia and globally has a long and variable history. In recent years, due to ongoing public concern over long-term environmental impacts, the mining industry globally has been moving towards a more sustainable framework, presented as the æMining, Minerals and Sustainable DevelopmentÆ (MMSD) framework at the Johannesburg Earth Summit in 2002. There are a number of fundamental issues and concerns with assessing the sustainability of mining. Firstly, long-term trends show that ore grades for almost all metals and minerals will continue to decline (some rapidly so), increasing waste rock is being produced due to the trend towards large-scale open cut mining and more complex ores are now commonly being developed. The impact of these trends on the resource intensity, or unit cost, of gold production is of major concern as it could lead to an increase in energy, water and reagent consumption and greenhouse emissions per unit gold produced. A detailed compilation of these fundamental sustainability indices for gold mining has been undertaken, and is presented with respect to indices over time, ore grade and ore throughput. A clear observation is that the resource intensity of gold mining is extremely sensitive to the ore grade, with energy, water and cyanide consumption and greenhouse emissions rising significantly as ore grade decreases. Based on the gold ore resources at operating mines and other known gold deposits, it is most likely that the average gold ore grade will continue to decline, leading to increased resource intensity and consequent environmental impacts (assuming no breakthrough new technologies occur). These findings are of major importance to understanding the sustainability of gold mining. The final judgement of the sustainability of gold mining therefore must take into account the sensitivity of the ore grade in the resource intensity of gold production.

Jan 1, 2007

By Giannini L, Kelsey P

A fundamental problem in mine planning is the determination of the production schedules over the life of the mine. The objective is to maximise profit in terms of the net present value without transgressing the physical constraints of the mine

Jan 1, 1998

By I M. van Waveren, F Hasibuan, M J. Crow

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Two Hg-Au occurrences west of Bangko, Sumatra occur within the West Sumatra Permian Volcanic Plutonic Arc. The Melipun Hg-Au occurrence was exploited in the past and mineralisation occurs within a hydrothermally altered cupola of a buried intrusion. The Salak Hg-Au occurrence occurs within the outcrop of the Dusunbaru pluton, likely within the remnants of a caldera in which hydrothermal mineralisation was developed. Both occurrences formed late in the history of the volcanic arc, probably between the Triassic and early Jurassic. The Melipun occurrence may have potential at depth, but that at Salak is small and lies within the area of a proposed Geopark.CITATION:Crow, M J, van Waveren, I M and Hasibuan, F, 2015. Two Hg-Au occurrences in the west Sumatra Permian volcanic-plutonic arc west of Bangko in Sumatra, Indonesia , in Proceedings PACRIM 2015 Congress, pp 573–578 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

Strategic planning in mining is an important value accretive process. One of the most important aspects during the planning phase is determining the correct mine and plant design. The traditional mine site design (mine, plant, stockpiles, dumps) develops a fixed system for one set of conditions or expected values. A robust design is a fixed system that is designed to deal with a large range of conditions without changing the system design. A flexible design changes the system dynamically in response to changes in uncertainties. It is hypothesised that a robust design generates less value than a flexible design as it fails to realise the value of actively managing the operation. One of the most critical aspects in creating strategic value from a project is embedded in the design of the system. A flexible design has components that allow the design of the system to change over time. An operational plan is proposed as a hybrid of a robust and flexible design. This paper seeks to compare these different design methodologies. An analysis of the same case study is undertaken to compare these approaches, showing an a traditional net present value (NPV) of $1678 M, robust design NPV of $1787 M and an operational plan NPV of $1867 M - an increase of $170 M.

Dec 6, 2010

Removal of Arsenic in Enargite from Copper Ores by Flotation and Leaching in NaHS Media

Sep 13, 2010

The investigations described in this paper aim at the development of a new impact mill. The objective is to produce particle size distributions below 10 .tm without using an air classifier. Circumferential rotor speeds of up to 200 m/s are strived for.

Jan 1, 1993

By K Palmer

Alluvial platinum was recovered during gold mining operations in Maud Creek, a tributary of the Howard River. Average electron probe analyses give Pt 88.75, Fe 5.27, Ir 0.70, Os 1.06, Pd 0.34, Ru 0.14, Rh 1.29, Cu 1.06. Rare grains of a Pt-Fe-Cu alloy are also present and an unusual feature of all grains is the relatively high rhodium content which finds expression in segregations of rhodium arsenide, cherepanovite. Platinum is found in the Orepuki area of Southland, where it is probably partly derived from the mafic rocks of the Longwood Complex. Rocks of the Rotoroa Complex, similar to those of the Longwood Complex, form bedrock in Maud Creek and are possibly the source of the Howard platinum. Alternatively, it might be derived by glacial transport from the Matakitaki ultramafic block 30 km to the southwest. Origin from the Rotoroa rocks is preferred as, if the Matakitaki rocks are part of the Dun Mountain Ophiolites, they might be expected to contain osmiridium rather than platinum. The ratio Pt:Ir-Os has been widely used to distinguish low Pt:Ir-Os ophiolitic from high Pt:Ir-Os gabbroic assemblages. Mafic complexes such as Longwoods, Darran, Rotoroa, and Riwaka might be expected to show similar high Pt:Ir-Os ratios and be targets for platinum exploration. Detrital platinum examined from the Parapara area, Golden Bay is mainly osmiridium, with rare grains of rutheniridosmine, very similar in composition to that found in concentrates from the Kaniere dredge, West Coast.

Jan 1, 1987

By L Torckler, R L. Brathwaite

At Neavesville gold-silver (electrum) mineralisation occurs in steeply-dipping zones of intense fracturing, brecciation and quartz veining within rhyolitic pyroclastics, carbohaceous shales and andesites. Hydrothermal alteration extends over an area of greater than 3 by 1.5 km. In rhyolitic tuffs, highly silicified zones containing quartz-adularia-illite assemblages are flanked by less silicified assemblages composed of albite, illite-montmorillonite and chlorite. The mineralogy and sequence of alteration are comparable with the alteration zones which envelop the steam-producing fissures of the active Wairakei and Broadlands geothermal fields. Primary fluid inclusions in quartz from five fissure veins in the Neavesville field show maximum homogenisation temperatures ranging from 220 - 260¦C and salinities of 0.0 - 1.1 wt per cent NaCl equivalent, which cover a similar range to actual measured temperatures and salinities in geothermal fluids at Wairakei and Broadlands. The age of the rhyolitic pyroclastics and related alteration and mineralisation is probably Pliocene and Neavesville therefore represents a fossil geothermal system. The intensely fractured zones containing the gold-silver mineralisation were probably produced by hydraulic fracturing generated by accumulation under pressure of hydrothermal fluid in blind fault zones. Study of fluid inclusions indicates that hydrothermal quartz associated with electrum was deposited under boiling conditions. High grade electrum mineralisation at Graces workings appears to be localised by reaction of hydrothermal fluid with sedimentary marcasite in black shale.

Jan 1, 1980

By M Bourke

Modern computers and software provide powerful tools for the geologist to construct reliable models of geological resources, and the mining engineer to produce accurate and workable mine plans. Over the years many people have developed a phobia of computers, especially for geological analysis, modelling and mine planning. This phobia is often caused by a lack of knowledge, poor training or a bad experience. The adoption however of computers for geological modelling and mine planning is now becoming mainstream. With the correct training, a good understanding of input data, and detailed knowledge of the required results, the phobia can safely be overcome to provide mining operations with increased productivity.

Jan 1, 1999

By R Lau

In recently completed road tunnel projects in Queensland, such as the Airport Link and the Clem7 tunnels, there is a smoke duct running along the roof of the carriageways to extract smoke in case of fire. In New South Wales, no road tunnels have a smoke duct. In the Melbourne City Link tunnels, there is a small smoke duct running along the roof. All of the tunnels are safe as claimed by the designers and authorities. However, there is significant cost associated with providing a full size smoke duct compared with no smoke duct. This paper is going to present a comparison of the road tunnel safety with a smoke duct and those without one from a risk perspective. It further discusses the cost-effectiveness of such provisions and whether similar levels of safety could be achieved without a smoke duct.CITATION:Lau, R, 2014. Smoke duct or no smoke duct for road tunnels, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 83–86 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

Mining in Guyana dates back into antiquity and a brief history of gold and diamond mining and of the small-scale miner, the pork-knocker, is given. The gold and diamond deposits found on the beds and in the flats of old and present rivers and the current methods of investiga- ting these deposits are briefly described. Methods of mining these deposits including the small-scale hand methods of pitting and diving with or without helmets are also briefly described. 'The small-scale method of dredging using a suction dredge in conjunction with a diver is described in more detail, from its develop- ment to current practice, without giving too much mechanical and technical details. The organisation of the industry and the mining titles, laws and policy relating thereto are reviewed. A brief account is given of the socio- economic role of the industry. Conclusions are made regarding the need for improvements in existing equipment and financing and for incentives to stimulate production. The future outlook of the industry is con- sidered.

Jan 1, 1986

The gold salting fraud at Busang on the island of Kalimantan, Indonesia was exposed in early 1997 and resulted from the independent drilling, sampling and assaying of PT Freeport Indonesia which reported assays from the South East Zone with negligible concentrations of gold. Since then, a number of legal actions directed at former Bre-X directors, consulting firms and financial or broking institutions are at various stages and are based on numerous allegations surrounding the supposed existence of obvious and numerous warning signs or æred flagsÆ. These include: the absence of references to visible gold in the drill logs; the alluvial nature of the gold grains; the high gravity recoveries; the invalid comparison with Kelian; the absence of outside scrutiny and the lack of external review/audit and surface depletion of gold. The focus on the red flags has been at the expense of the numerous positive indications or ægreen flagsÆ. These include the morphology and chemistry of the gold grains, the gravity testwork, the amalgamation results, the role of external consultants, the results of a review by one of North AmericaÆs leading minerals auditing groups, the behaviour of the gold at surface and the presence of references to visible gold in the drill logs. The flawed nature of the discussion of the technical facts surrounding Busang has prevented a meaningful and informed discussion about what actually happened and has, therefore, prevented the formulation of meaningful remedies for the future.

Jan 1, 2002

Optical sensors have emerged during the telecom boom in the late 1900s, due to the availability to low-cost telecom-grade optical components. It's only after the telecom industry's fall in 2004 that optical sensors became sufficiently developed to be a viable technology for real-world applications. Geotechnical applications have long relied on electrical sensors such as thermocouples, strain, and the venerable vibrating wire to measure physical phenomena. Although these are well suited for a large variety of applications, electrical sensors cannot be used for all applications: these are vulnerable to noise, hazardous voltages and corrosion, limiting the environments in which they can be used. In addition, electrical wires can also become an issue when sensors require external excitation or are distant from the measurement system. Finally, changes in physical properties of electrical sensors and systems over time makes regular calibration a necessity - not easy to do when these are permanently mounted on structures. Optical sensing systems are non-conducting and use light to perform various measurements. There are several optical sensor technologies available, each with different strengths and weaknesses. In addition, there are different methods of interrogating optical sensors, each of which also present different strengths and weaknesses. To make matters worse, configuring the interrogation and scaling to physical units can also be challenging to the unprepared engineer. This paper will present a holistic view of optical sensing, presenting the different optical sensor technologies and interrogation techniques. Sample optical sensing systems will be revealed and top considerations for optical sensing will be presented.

Nov 25, 2010

The Pike River Coal Company is set to develop the Pike River Coal Mine in the Paparoa Ranges of New ZealandÆs South Island. The mine will be developed to extract a coking coal deposit of the Brunner Seam, some 46 km north-east of Greymouth, using a combination of continuous miners and hydraulic extraction.   The mining area is located within Department of Conservation (DOC) land and is adjacent to the escarpment of the Paparoa Range and the Paparoa National Park. As such, the major restriction to planned extraction is protection of:   +        the western escarpment, +        vertical and sub-vertical rock faces, +        permanent water courses, +        significant vegetation, and +        steep slopes.   The mine will use its elevation advantage to hydraulically flume coal from the working faces to the pit bottom area where it will be slurried to approximately 35 per cent density of solids and pumps down a slurry line to the coal prep plant some 10.5 km down the Pike River Valley. The coal will be sold on the export market as a high quality coking coal for international steel making.

Jan 1, 2005