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By Stuart M. S, Allen P. B

The Childe Harold deposit was mined by the Granny Smith Joint Venture (GSJV) from late-March through to early-December 1993. This was a fast-tracked mining project whose history began with an offer to purchase agreement being signed at the end of October 1992. A feasibility study was completed by the end of December 1992 after completion of a reverse circulation (RC) and diamond drilling program. Subsequent additional definition drilling culminated in a remodelling of the reserve by March 1993, by which time all necessary governmental and company approvals had been granted. The crucial aspect of mining Childe Harold quickly was to maintain oxide ore supply to the Granny Smith mill at the maximum possible rate for blending with existing fresh ore stocks. As a result, high production rates had to be balanced with

Jan 1, 1994

By Roe P, Lowell A

This paper outlines software development and design work carried out by Mincom Pty Ltd in collaboration with Capricorn Coal Management (CAPCOAL) for computer based design of rehabilitated strip mine landforms at German Creek Mine. Current developments and future application areas for this software are also discussed in relation to other mines in Central Queensland. The development program was initiated in response to statutory requirements placed on mining companies in 1990 to produce a five year Plan of Operations which was to include a contour plan of the final rehabilitated mine landform at the end of the five year planning period. This plan was to be submitted to the Department of Resource Industries (DRI) by 1 December 1990. Due to the limited time given to prepare the plan, a work program was formulated in collaboration with Mincom Pty Ltd to develop suitable software to carry out the design work and provide the required plans and quantities. The software had to include computer based methods to allow design of the proposed landform in line with the rehabilitation strategy adopted by CAPCOAL at the time.

Jan 1, 1991

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

By Drain P, Dibdin T. R

THE completion of the Linda incline man and supply haft at the Mount Morgan Gold Mining Oompany's mine led to an investigation of the various safety gears in general use in mining shafts. One of these gears completely fulfilled the necessaryconditions. This paper endeavours to give a description of the man car and safety gears now operating in the before mentioned shaft, together with the main considerations leading to their design and sub equent adoption. Fig 1 diagramatically shows a longitudinal section of this shaft.

Jan 1, 1911

By Haslam C. O, Los V. L, Abramson G. J

The technology applied by lonex Pty Ltd provides an important breakthrough in geochemical exploration, enabling the discovery of concealed mineral deposits to great depths below surface. Most mineral discoveries have been made in areas of outcrop or relatively shallow cover; deposits at greater depth have been beyond the range of conventional geophysical and geochemical methods. Quite apart from the need to explore to greater depths in regions of major current or past production, most continents have vast areas where prospective host rocks are concealed by more recent material. There are numerous case studies where Ionex methods have located deeply-buried metal deposits, up to 500 m below surface, beneath thick younger sedimentary, volcanic, or transported cover. Research leading to the development of this technology was initiated by Dr I S Goldberg at the Rudgeofizika Institute in St Petersburg (CIS), and the methods have been employed there - and in other countries - for many years. Ionex technology became available in Australia in 1993. It comprises: ò geochemical and geoelectrochemical sampling and ultra-high-sensitivity analysis for mobile and weakly-bonded elements (I S Goldberg); ò the delineation and interpretation of regional zones of enrichment and depletion of the prime elements within geoelectrochemical systems (GES) (I S Goldberg); ò the investigation and interpretation of the three-dimensional geochemical zoning within geochemical anomalies (G J Abramson); and ò multi-variate computer modelling of the geochemical fields and systems (V L Los). lonex technology has been adapted to the environmental conditions in Australia with the participation of C 0 Haslam.

Jan 1, 1997

By M Field

Kimberlite pipes, as opposed to dykes, sill and secondary deposits, are the primary target for diamond exploration companies because they have simple geometries and can contain large volumes of potentially diamond-bearing ore. Once discovered, important decisions have to be made regarding the sampling of these geological entities to establish the total volume of ore present, and to define the internal geology, which can be complex in nature and controls the distribution of diamond grade. It is essential that as part of this process the uncertainty in constructed geological models are assessed. In this paper the Orapa AK1 kimberlite pipe in Botswana is used as a case study to explore a potential methodology for defining this uncertainty. The uncertainty of the rock volumes of different types can be characterised by a geostatistical approach. Geostatistical simulations, based upon a plausible representation of the geological bodies, provide different possible images of the orebody that can be considered as different realities. By testing different borehole layouts and drilling the orebody virtually on the computer, many different, but equi-probable realisations of the pipes can be produced. It is then possible to estimate the rocksÆ volumes and compare them with the actual ones. A statistical analysis of the relationship between estimation error and the number of boreholes can then be used to optimise the next sampling campaign. The rock volumes are obtained from a two-step simulation process. Firstly, the pipe geometry is simulated by means of introducing variations around the geological block model, by an original method called centre point simulation (CPS), which has been developed for this purpose. Secondly, the internal geology is then simulated within the pipe. The methodology for simulating the internal geological zones has to be adapted to the level of information and to the geological structure itself. The upper portion at Orapa AK1 is filled with sedimentary crater facies. Here plurigaussian simulation techniques can be applied that are adapted to the simulation of sedimentary facies. The central zones of the pipe are typically subvertically-oriented massive volcaniclastic deposits and breccias and the lower regions comprise a complex root zone. CPS is appropriate for these zones.

Jan 1, 2006

In June 1992, the High Court of Australia recognised native title of the Meriam people over parts of the Mer Island in the Torres Strait as a form of common law. The Court also indicated that native title may have survived European settlement of the mainland Australia where it had not been extinguished by Governments and Aboriginal people have maintained their traditional connection with the land. The decision meant that two systems of land law were seen as existing side by side in Australia: ò one which derived from grants from the Crown under laws passed by Parliament; ò another which derived from the diverse laws and customs of the many Aboriginal groups in Australia.

Jan 1, 1996

By Toguri JM

A solid electrolyte technique has been used to measure the activity of cobalt in liquid cobalt-gold alloys containing between 0.085 and 0.50 mole fraction of cobalt, and for temperatures from just above the liquidus to around 1550 K. The system exhibits positive deviation from ideality, both in the activities of cobalt and gold, and in the enthalpy and excess entropy of mixing. The results agree with previous measurements using a Knudsen cell - mass spectrometer technique, but differ from those reported for a gas equilibration method. The data have been used to calculate the activity coefficient of cobalt oxide in silica saturated iron silicate slags and to express the solubility of cobalt in such slags as a function of cobalt activity and oxygen pressure.

Jan 1, 1984

By Francis R. S, Campbell J. J

Aberfoyle's Hellyer Division has filtered very fine flotation concentrates using two different makes of pressure filter. At the Luina concentrator a Larox pressure filter was used to treat a combined Pb + Zn or bulk concentrate. At the Hellyer concentrator two Lasta pressure filters are being used to filter copper/silver, lead, zinc and bulk concentrates. Operating parameters and performance at both operations are described. In both concentrators it was found that correct cloth selection was critical and that cloth failures contributed significantly to downtime. Thorough preventative maintenance progammes were required to ensure adequate availability of both makes of filter.

Jan 1, 1989

By R Bunduwongse

The oil crisis had repercussions throughout the world and most importantly on mining, where the drive to reduce the use of liquid fossil fuel led directly to the appearance and subsequent growth in the design of mobile crushers in late 1970s early 1980s, which heralded a new era in both quarrying and mining. Even though mobile crushing has now become common, even preferred in the quarrying industry, this has not been the case in mining. This paper looks at why, in spite of the initial optimism, this technology has yet to gain full acceptance in the mining industry. The paper examines some of the problems that have been encountered in the past and offers suggestions as to how they can be avoided by applying the appropriate technology. It then takes a look at the successful application of the semi-mobile in-pit crushing system used by Italian Thai Development Company (ITD), on the Mae Moh Phase 5 contract and examines how the techniques used successfully there could be applied to the industry at large.

Jan 1, 2007

By Windsor C. R, Thompson A, Bywater S

A new high tensile strength, steel cable, that may be grouted into boreholes has been developed for use as rode reinforcement. The manufacturing technique produces a birdcage pattern in which the cross section varies along the length of the cable. The load transfer from cement grouts to birdcage cables has been demonstrated in laboratory tests to be better than that of standard 15.2 mm diameter seven wire cables. The manufacturing process also allows for a wide range of capacities which may be specified by design engineers. The various birdcage cable configurations have been applied as rock reinforcement in a number of Australian underground and surface mines.

Jan 1, 1990

By J D. Lubben

Hibbing Taconite is a Lake Superior-type granular magnetite taconite deposit occurring within the Biwabik Iron Formation along Minnesota’s central Mesabi Iron Range. The deposit is situated on the northern margin of the Proterozoic Animikie Basin. The deposit strikes northeast, dips gently southeast, and occupies 10 km of strike length. Mining focuses on 50 m of granular cherty and laminated slaty taconite within the Lower Cherty member.Ores generally consist of a quartz, magnetite, siderite, ankerite, minnesotaite, stilpnomelane, and haematite mineral assemblage. Processing is optimised by exploiting the physical and chemical variations that exist between three major ore types. Taconite ore averages 20 per cent magnetic iron (MagFe), 27 per cent weight recovery (WtRec) and produces a final concentrate with 4.5 per cent silica (SiO2). Since 1976, production has totalled approximately 237 million long tons (Mlt) of pellets (8 Mlt per year rated capacity).Ore processing uses a simple fl ow sheet of autogenous grinding (<0.044 mm) followed by two phases of wet magnetic separation, fi ltering, limestone/bentonite addition, balling, and firing to create pellets averaging 66 per cent total iron. A Liberation Index (LIS) is used as a primary guide for ore grading and metallurgical control. Grind requirements, magnetite liberation and silica grade are closely monitored to ensure plant optimisation and product quality.A recent program of benefi ciation of low-grade ores by in-pit crushing and dry magnetic cobbing has demonstrated that low-grade ores (<17 per cent MagFe, <25 per cent WtRec) can achieve a signifi cant metallurgical upgrade (up to 25 per cent MagFe and 40 per cent WtRec). This operation recovers 60 per cent of the total crushed volume, and has a calculated effi ciency factor (magnetic iron recovery) of 79 per cent. This paper discusses the benefi ts of this upgrading and its effects on ore blending and processing.

Jul 11, 2011

By Loo C. E

Thirty two polyacrylamide flocculant samples were selected from the wide range offered to the Australian coal industry. An extensive test program was conducted to consider the properties of the flocculants, the substrates, the process conditions and the water chemistry encountered in coal preparation plants. The study indicated that flocculants with molecular weights of 12 to 14 million and degree of hydrolysis around 40% gave the best "average" performance over a wide range of process conditions. The pick-up and filtration of fine coal was demonstrated on a pilot scale to be a critical function of flocculant properties. This study also showed that the agitation intensity during flocculation was a critical parameter in determining the settling rate of the slurry and the clarity of the resulting supernatant. An electronic meter to measure agitation intensity was designed, constructed and tested to demonstrate how, for the first time, laboratory results can be implemented in operating plants.

Jan 1, 1989

By Peck J. P, Kennedy D

Drill performance monitoring studies were recently completed at the Fording River mine, British Columbia. Microprocessor-based instrumen- tation and data analysis techniques were developed with the objective to improve short and long term mine planning. Data analysis permitted the identification of thicknesses and interfaces between soft/hard zones at depth based upon the recorded responses of the drill. Data clearly con- trast the soft coal seams and harder waste rock units based on variations in recorded drill rotary speed and torque, hydraulic downpressure, bail- ing air pressure and instantaneous rate of penetration. These parameters were monitored and recorded at 10 cm sampling intervals. Processed drill data was correlated with gamma logs, an existing means for locating coal seams and distinguishing between waste units. Current development of a pattern recognition module aims towards automated interpretation of drill data, identifying micro-and macro-geological and geomechanical rock mass characteristics. Delay between acquiring, processing and interpret- ing the drill data for practical use by mine personnel should be minimized. Integration of this technology with the mine's current main-frame based Mine Engineering Application System software will enable more accurate and timely annlication of the nrocessed drill data.

Jan 1, 1989

The Ok Tedi Project has been planned as a selective mining operation since the Feasibility Study. The nature of the orebody, and the need to 'stage' the infrastructure buildup meant that initially the mill would process gol ore using a leach-CIP process, followed by parallel leaching of gold ore and flotation of copper ore, and finally all flotation of copper ore. Cutoff grades were applied to gold and copper ore of 1.0-1.3 g/t Au and 0.4-0.3% Tot. Cu. Since startup, unpredicted occurrences of sulphide copper and, to a Lesser extent, carbonaceous material, has necessitated significant additional short term drilling (other than at grade boundaries), and shift grade control in the pit to control contaminant levels. Remodelling of the orebody based on the most up to date variography and geological interpretation has had a significant impact on the reserves, and thus the whole project development strategy; necessitating the earlier processing of copper ores, and preflotation of the gold ore.This paper discusses some of these points in detail, and in particular highlights how unforseen geological occurrences coupled with processing restrictions can have significant impacts on ore reserves and the mine development schedule.

Jan 1, 1986

By Lu T. K

A new type of rockbolting system, the self drilling rockbolt, has been studied to develop a 'single pass' bolt for use in rockbolt installation in underground engineering. This single pass bolt forms the basis of a Rapid Face Bolting system which will reduce the amount of time spent in securing a roof during the operation of a continuous miner in the development of a panel.The installation efficiency and anchorage tests were performed in the laboratory on the self drilling bolt and the traditional resin anchorage. bolt. The results of both bolts are cmmnared.

Jan 1, 1993

By Zhansen P

This paper describes the test re- sults which give a complete proccess of failure of concrete lining embedded in sand medium under load, including the order of appearance of crack along the lining up to failure. nor each crack appearance corresponding calculation being made to assess the redistribution of moment and thrust force in critical section including crown section, section making 45¦ with the vertical etc. De- flection at the above stated critical sections are also measured at each stage of loading. The pressure along the top hori- zontal surface of embedded lining and the vertical sides are measured by pres -sure gauges embedded in sand medium. fhe test results show a complete figure of rupture characteristics of concrete lining embedded in soft ground which approximates alluvial deposite often occur in metro construction at cities near the river side. These test results have been taken as a reference in assessing the action behavior of concrete lining in certain cities in China.

Jan 1, 1987

A failure of the Pit IA highwall in July 1989 led Newcrest Mining Ltd's Telfer Gold Mine to commence underground operations approximately 12 months ahead of schedule. The failure presented four major challenges to management: 1. how to maximise the recovery of the Middle Vale Reef (MVR) in the open pit: 2. how to minimise the risk to personnel involved in the extraction of the remaining open pit ore; 3. how to avoid disruption to ore supply: and 4. how to maintain a permanent and safe means of accessing the underground operations from the base of the pit. The risks associated with meeting these challenges were minimised through the installation of a complex network of real time slope monitoring equipment. These monitors were connected to an alarm system which was combined with detailed operational procedures to be carried out in the event of a highwall alarm being triggered. The accuracy with which the risk of failure has been managed was demonstrated recently when the onset of a second failure was initially identified some 13 months prior to its ultimate collapse in October 1992. The location, timing and size of the failure was able to be predicted allowing appropriate precautionary measures to be taken to ensure safety of access to the underground portal and pumping equipment in the base of the pit. This paper reviews the sequence of events leading to both the July 1989 and October 1992 failures of the Pit 1A highwall and the monitoring equipment and procedures used to identify, quantify and manage the risk to personnel operating in the base of the pit.

Jan 1, 1994

By Yagi Y

The double track railway tunnel, called the Second Shirasaka Tunnel is being constructed under the supervision of Japanese PTational Rail- ways (JNR) in the tertiary soft rock strata in order to speed up the railway transportation. This tunnel (L=1765m), located in a central part of Japan, is excavated by the machine (roadheader), while the adjoining First Shirasaka Tunnel (L=1296m), completed five years ago, was driven by the blasting, and NATM is adopted in both tunnels. The geological features in this region are Neogene Tertiary of Miocene sediments consisted of mudstone, the sandy mudstone and the alter- ation of these rocks, having a squeezing be- haviour. And the geological structure is as complicated as some anticline and syncline structures, large or small scale exist, and as a lot of faults are found. The machine excavation manner using road- header is adopted in this tunnel to minimize the effect of excavation because there is a possibility of the occurrence of landslide due to the tunnel excavation, and also because local inhabitants reside on the ground surface.

Jan 1, 1987

By Michot LJ, Kongolo M, De Donato PH

Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), Hallimond tube flotation tests and microelectrophoresis measurements have been used to investigate the reactions involved in the adsorption-ion of K-amyl xanthate on finely ground pyrite. Pure pyrite was finely wet ground, at different pH values, in specially built laboratory stainless steel or iron rod mills. Amyl dixanthogen was the only product identified on the surface of pyrite when stainless steel rods were used. When iron rods were utilised, ferric xanthate and physically adsorbed xanthate ions were observed in the superficial phase. The use of iron media was found to depress slightly the floatability of the mineral.

Jan 1, 1993