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By Stanley I. M, Brett D, Dickson R

The Mt Lyell Mine, situated in Queenstown on the west coast of Tasmania, has a production history of more than 100 years. Previous mining activities have resulted in substantial modifications to environmental conditions at Mt Lyell and disposal of sulphidic waste rock across the lease has left a legacy of on-going environmental impacts including acid drainage (AD). In 1995 Copper Mines of Tasmania (CMT) was granted a mining lease Irons the Tasmanian State Government for redevelopment of Mt Lyell and indemnity from actions concerning pollution from previous occupation and use of leased land. The Environmental Management Plan (EMP) for the Mt Lyell redevelopment committed CMT to be responsible for waste rock dumps generated from their activities and to ensure that management is in-line with best practice environmental management principles. CMT commenced commercial production in December 1995 with sulphidic material from development of the underground Prince Lyell mine reporting to a single waste rock dump constructed according to a management plan developed in July 1995 and superseded by a management plan for extension in May 1997. The CMT waste rock dump currently has a total capacity of 220 000 m- and approximately 120 000 m3 of rock have been placed to-date. Material reporting to the dump is placed in a densely compacted state to a controlled surface profile. The dump is clay capped and a final revegetated soil layer placed on top. A rock pitched drain extends down to a wetland area in order to remove stormwater and minimise possible soil erosion on the revegetated sections. An integral part of the management plan for the waste rock dump involves characterisation of waste rock to identify geochemical rock types according to acid forming potential with provision for selective placement within the dump. High-risk materials are selectively placed and covered within the core of the waste rock dump, where possible, to control sulphide oxidation. Monitoring equipment has been installed in the waste rock dump by the Australian Nuclear Science and Technology Organisation (ANSTO) and an on-going monitoring program has been established to demonstrate the integrity of the dump cover as a barrier to the influx of atmospheric oxygen into the dump. The overall objectives of this program of work are to control the oxidation of sulphidic waste rock in the waste rock dump, minimise the risk of AD, prevent pollution of the aquatic environment and thereby demonstrate the integrity of the CMT waste rock dump management Strategy.

Jan 1, 1997

By Yates M. G, Rowlands A. T

Most geostatistical techniques applied to the estimation of ore reserves assume relatively unifonn grade and thickness within an ore deposit environment. In shear-hosted mineralisation this rarely occurs. The distribution of mineralisation is controlled by the kinematic and geometric variation within the shear zone. Although the kinematic variation is dependent primarily on the temperature (and consequently the depth) of formation of the deposit, the geometric variation appears to be relatively insensitive to this parameter. Shoot mineralisation is controlled either by the intersection of secoodary shear planes (brittle deformation) or the stretching lineation of the mylonitic fabric (ductile defonnation).Once the shear geometry is clearly identified, it is critical to review the distribution of grade and thickness of mineralisation. The practice of cutting high-grade intersections without reference to the shear model leads to underestimation of the amount of gold in the deposit. High-grade shoots may occur as pipe-shaped bodies within the system; their identification is essential for both resource estimation and mine planning purposes.

Jan 1, 1991

By Smith S. F, Terezopoulos N. G

This paper discusses experimental results of physical scale models employed to study the stability of a pillar between rectangular roadways. A programme of laboratory investigations utilising a bi-axial test rig has been undertaken to examine the influence of various stressfields on the stability of pillars between mine roadways. The effect of pillar height/width ratio on the overall stability is studied. Observations of failure characteristics in and around pillars are discussed especially in relation to the various stressfields applied to the models.

Jan 1, 1992

By He F, Zhu D

How to monitor and control the support and surrounding strata system on a longwall face effectively is one of the major research problems in ground control. Based on observations on movements of the support and surrounding strata of face No. 2703 of Dongpang colliery, the relationship between the downtime related to support and surrounding strata and other influential factors is analysed systematically in this paper. Monitoring indices and control measures are then determined by taking corresponding downtime as an objective function. When the monitoring method, developed from the above findings, was used on face No. 2703, the downtime due to support and surrounding strata was remarkably reduced, and the face advanced Normally.

Jan 1, 1992

The Skybolt is a new bolt concept, point anchored with resin in large diameter holes of specific sizes 38 mm and 45 mm. The new design achieves the optimum annular spacing required for mixing the resin anchor components which is essential for optimum resin bonding of the bolt to the surrounding rock. This paper explains the load transfer mechanisms between bolt/resin/rock, unique to this bolt concept. It compares the pull-out test results to those of paddle and expansion shell type bolts, and highlights the versatility of Skybolt over existing, currently used, rock support systems and the benefits mine operators can achieve when using the Skybolt.

Jan 1, 1992

By D P. Obeng, L Reemeyer, R Holmes

The Zinifex Century Mine employs a large number of Detritor mills for fine and ultra-fine grinding to liberate silica and sphalerite at 80 per cent passing 7.5 microns before final zinc flotation. A joint project between CSIRO Minerals and the Zinifex Century Mine was carried out to evaluate the Detritor mill performance. Plant surveys were conducted around the Detritors in conjunction with laboratory tests. The survey data showed that the Detritors in the ultra-fine milling circuit performed well. They reduced a feed F80 sizing of 46 microns to a product P80 sizing of 7.5 microns at a gross energy consumption of 37.2 kWh/t. Scale-up of ultra-fine milling Detritors was studied using a 0.55 kW laboratory batch unit and a 355 kW full-scale Detritor by processing Century zinc concentrate with 1 mm sand media. The results indicated that the 0.55 kW laboratory mill underestimated the energy consumption of the full-scale Detritor by about 20 per cent for a product P80 of seven microns. The performances of a horizontal IsaMill and a vertical Detritor were compared as ultra-fine milling devices for processing Century zinc concentrate. The experimental data demonstrated that, when using the same grinding media, the energy efficiency of the two mills is similar despite the difference in mill designs. The Detritors used for regrind duty at the Century Mine performed poorly when processing feed at 80 per cent passing 88 micron. The energy consumption was high and the product size distribution was broad with particles above 100 microns in the feed unbroken and particles below ten microns overground. A coarser ceramic media of 3 mm was therefore tested in a laboratory Detritor to process the regrind Detritor feed as an alternative to the 1 mm Colorado sand used at the Century Mine. The ceramic media reduced the energy consumption significantly and produced a narrower product size distribution, which is more desirable for the downstream flotation process.

Jan 1, 2007

By Mroczek C. R, Evans D. A

Renison is a world-class ore deposit that has been mined for over 100 years. It currently has reserves of 5.06 Mt @ 1.88 per cent Sn and a projected mine life of 8.5 years. Recent advances in the geological understanding of the deposit have been associated with detailed structural and geophysical investigations accompanied with the discovery and exploitation of the Rendeep orebodies. Mineralisation is linked to the forceful emplacement of the Devonian Pine Hill Granite that resulted in a complex brittle (-ductile) deformation of the Eo-Cambrian host stratigraphy. Dilation jog development on the Federal-Bassett Fault in the Federal and Rendeep areas provided access for cassiterite-rich magmatic hydrothermal fluids responsible for carbonate replacement Mineralisation.

Jan 1, 1997

Diamonds have been known in Australia for many years, especially in association with alluvial gold and tin occurrences. Exploration for primary sources in the Kimberely area of Western Australia has been carried out since 1968, culminating in the discovery, in 1979, of the Argyle Kimberlite No 1 (AK1) kimberlite pipe. Various techniques have been used in the search for diamonds such as geologic interpretation, aerial photography and Landsat, soil geochenical techniques, geophysics, and stream sediment sampling. Stream sediment sampling, a method developed in South Africa, using the detection of indicator minerals derived from kimberlites in gravel samples, has had wide application and success in Australia. Nevertheless, although Australian diamond bearing kimberlite and lamproite rocks contain some of the classic indicator minerals, their concentrations are generally much lower than in South Africa and Russia. Despite this paucity of indicators, stream sediment sampling is still the best known and most commonly used method of diamond prospecting in Australia. Small samples are treated by hand but larger samples require the use of diamond pans, jigs or heavy media separation plants. Each of these methods has advantages and disadvantages. The final concentrate is passed over a grease table or subjected to x-ray sorting.

Jan 1, 1984

Data logged on mineral beneficiation processes during normal operation are analysed using time series (correlation and spectral) methods to identify the dynamics of the processes for on-line computer control. Recursive least squares estimation techniques are used to identify parametric models for a cassiterite flotation circuit and a coal washery. Identification problems such as the determination of model order, process time delays and the 'contamination' of the data by process recycle streams (feedback) are discussed. Typical results are presented in which optimised models are identified from data logged during normal operation.

Jan 1, 1985

The mining industry provides employment opportunities for individuals from a wide variety of disciplines. Solid Energy New Zealand Limited (Solid Energy) is New ZealandÆs largest coal mining company and the career opportunities for school leaver trainees and university graduates are numerous. Solid Energy also provides fixed term opportunities for consultants and contracting companies, who complement the wealth of knowledge already within the company.   Focussing on Stockton Mine and my involvement there as an Engineering Geologist, this paper looks at Stockton Mine and the Stockton Water Management Project and outlines the career paths of other young professionals also working at Stockton.

Jan 1, 2007

By Barnett J. C

The arid and semi-arid region of Western Australia occupies about two-thirds of the State equivalent to an area of about 1.8 million sqkm. Groundwater demand in this area has historically been linked to the pastoral andmining industries commencing with the gold discoveries in the Eastern Goldfields some 100 years ago. Substantial increases in demand have occurred in the past two decades initially as a result of nickel discoveriesin the early 1970's and more recently the rapid resurgence of the gold mining industry. Mineral exploration and development in the Great Sandy Desert at Telfer (gold) and Kintyre (uranium) and in the Great Victoria Desert at MulgaRocks (uranium) has also been accompanied by detailed groundwater investigations.

Jan 1, 1988

The Racecourse Orebodies at Mount Isa consist of a series of parallel steeply dipping lead/zinc/silver orebodies with a strike length of up to 1000 metres. Production from these orebodies between 13 Level to 9 Level has been by a series of cut and fill stopes in two level stages, leaving a crown pillar at 11 level. Development of the 15 level to 13 level extraction stage has recently been completed. The layout consists of a series of parallel stopes over a strike length of 1200 metres. Access to the stopes is by two declines connecting the stopes with a series of crosscuts This paper describes the basic layout with development and production methods employed.

Jan 1, 1977

The most appropriate technology needs to be applied to premining geological investigations to achieve reliable data for predictions of geological conditions ahead of mining. The paper describes the application of various investigatory techniques in BHP's Illawarra Collieries which are used to provide reliable assessments of structure, the nature of the coal and surrounding strata,, and the fluids contained in the strata. The techniques used include surface seismic, in-seam seismic, borehole drilling, electromagnetic and aeromagnetic surveys, hydrogeological investigations and in-mine mapping. The results of various case studies are presented as examples of the application of techniques.

Jan 1, 1988

The Highlands Region of Papua New Guinea has 3 major national highways. The locations of these national highways are shown in Figure 1. The Highlands Highway begins at Lae City on the coast and passes through the Highlands towns of Goroka, Kundiawa and Mt Hagen. It terminates at Togoba approximately 10km out of Mt Hagen town. The Enga Highway begins at Togoba and passes through the towns of Wapenamanda, Wabag and Laiagam. It terminates at the giant Porgera Gold Mine. The Southern Highlands Highway also begins at Togoba and passes through the major towns of Mendi, and Tari. It terminates at Koroba station, near the Hides Gas Field. Two separate Feeder roads intersecting the main highway service both the Kutubu Oil Project and the Hides Gas Field. These national Highways play a very important role in the development of Papua New Guinea. Goods and services are delivered to the bulk of the population of the Highlands Region using these highways. Heavy machinery and equipment for the mining and petroleum projects of Porgera, Hides and Kutubu are transported using these roads.

Jan 1, 1997

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

Thirty six different commodities were recorded from 3708 mineral occurrences in the Atherton 1:250 000 Sheet area, mapped by personnel of the Queensland Department of Resource Industries. Tin, occurring in 56% of all mineral occurrences, is the most common, followed by copper, tungsten, silver, lead, gold, fluorite molybdenum, zinc and antimony. The densest area of mineral occurrences is the Herberton Mineral Field, one of the most intensively mined areas in the state.The majority of occurrences in the sheet area are fracture, fault or shear related vein or lenticular deposits, with subordinate types being pipe, skarn, endogreisen, disseminated and porphyry copper deposits. However the larger mines in the area are commonly of the subordinate types including the Red Dome gold-copper skarn, the Wolfram Camp and Bamford Hill tungsten- m olydbenum endogreisens, and the Vulcan pipe tin deposit. Significant gold prospects occur in quartz-antimony veins, breccia pipes and skarn deposits associated with rhyolitic porphyry dykes. A fluorite-gold association has been noted in several areas on the western side of the sheet.Mineralised fractures are predominantly oriented in a NNW direction which is the major trend in the Hodgkinson Province. Secondary N and NE directions are also present.

Jan 1, 1990

By Hara Y, Arino S, Nakamura M, Tachimori M

The theoretical and experimental studies have been done to clarify the hearth flow of iron and slag. The results of dissections show that the hearth can be treated as a packed bed of coke hav- ing good permeability with a coke-free layer at the bottom of the hearth. 3-dimensional numerical calculations of hearth flow with and without a coke-free layer are carried out, and the results are assured by a water model simulation. The influences of a coke-free layer on the iron flow and the discharge route of iron and slag are examined. The 3-dimensional flow pattern can be represented simply by the travelling time, which depends on characteristically the profile of coke-free layer and the quantity of iron in the hearth. Those flow parameters could be obtained by the results of radioisotope tracer test ( Co for iron flow, and Sc for slag flow) at several furnaces. As a result, it is found that the coke-free layer repeats the cycle of appearance and disappearance at several-month intervals. This cycle corres- ponds to large temperature fluctuation at the bottom of hearth. The relation between iron flow and skull (solidified iron, coke and deposited graphite mixed layer) on the hearth brick was studied by the model experiment and the thermal analysis based on the indications of thermocouples installed in the bottom of the hearth. If a thin coke-free layer is formed on the skull, a fast iron flow is generated in the layer, and melts away the skull. The growth and melting of skull produces the fluctuation of thermal load on a bottom brick, causing brick Damage.

Jan 1, 1981

By OÆShea P. J, Dickson T. W

In April 1994 the Victorian Premier announced new State initiatives, collectively termed the Victorian Initiative for Minerals and Petroleum (VIMP), for exploration totalling $16.5 m over three years. The program, initially centred on the northwest of Victoria, the Eastern Highlands and the Otway Basin, is due for completion in June 1997 and has been designed to attract explorers to highly prospective but currently under-explored parts of the State. Major components of the program include acquisition of geophysical data (including airborne magnetics and radiometrics, gravity and seismic data), stratigraphic drilling, geological mapping and mineral resource data compilation. At the completion of the current program, 70 per cent of the State will have been covered by airborne magnetic and radiometric coverage at 400 m line spacing or better (Figure I) while 20 per cent of the State will have been covered by new geological mapping. The completion of database compilations for geochemistry, mine data and exploration licence summaries during the VIMP program is shown in Figure 2. The new airborne geophysical surveys have been flown partly under the VIMP program and partly by AGSO under the National Geoscience Mapping Accord (NGMA). Data from these surveys have been interpreted and incorporated into the geological mapping in order to enhance the quality of map products, especially in areas of Cainozoic cover. The first series 1:250 000 scale geological map coverage of Victoria was completed by the Geological Survey of Victoria (GSV) in 1977, and was based on compilation of historical geological mapping with minor field checking in most cases. The first metric 1:50 000 scale geology maps were also commenced in the 1970s, but were discontinued in the 1980s in favour of 1:100 000 scale map production. Driven by customer survey findings and with the benefit of detailed airborne geophysical data in the 1990s, the GSV reverted to 1:50 000 scale map production in 1995, with 1:10 000 scale maps made in areas of significant gold production. Geological reports still cover standard 1:100 000 scale map areas, but are now accompanied by four 1:50 000 scale maps. These new series 1:50 000 scale geological maps have been supported by comprehensive mine data and exploration licence summary databases in addition to the new geophysics, and benefit from the advances made in structural geological interpretation over the last decade. The new phase of geological mapping in Victoria, commenced under the NGMA in 1990 and accelerated under VIMP in 1994, has been focused in the central Victorian goldfields and eastern Highlands areas of the State (Figure 1). Results to-date have led to a number of major advances in the understanding of the eeoloeical evolution of Victoria.

Jan 1, 1997

By Seneviratne SP

The excessive displacement of the seam floor in headings (i.e. roadways) called 'floor-heave' is often experienced in the underground mines of the Southern Coalfield of New South Wales. Apart from interfering with the mining operations, the phenomenon could be detrimental to the stability of the pillars left for support leading to an unpredictable increase in the subsidence of the overlying strata. The latter could pose a serious problem, particularly in the design of partial extraction layouts of mining for areas where subsidence is to be controlled. The susceptibility of the floor of different rock materials and thicknesses in a given `panel and pillar' partial extraction geometry was examined by two- dimensional Finite Element Modelling of the displacements, stresses and failure zones around the excavations. The modelling, assuming elastic behaviour of the materials, indicated that the maximum vertical displacements of the floor increased substantially as the Young's Modulus of the material decreased to less than 7GPa and the thickness of the layer increased. The results also discount the possibility of a properly designed panel and pillar geometry in the Southern Coalfield of New South Wales being unable to adequately control surface subsidence through the pillar, or its core independently of the yielded ribs, penetrating the floor.

Jan 1, 1992

This paper considers two particular empi- rical models for the processes of the generati- on of hydrochemical zoning and epithermal near- surface mineralization of mercury-antimony-arse- nic formation in the discharge area of the Uzon Caldera ore generating hydrothermal system in Kamchatka. Vertical and horizontal hydrochemical zo- ning is caused by mixture of infiltration waters of the surface formation with fluid of chloride- sodium composition which are supplied up the-zo- ne of deep fault. Ore formation is caused by simultaneous existence of two geochemical barriers, namely oxidizing and reductive. The first barrier is determined by the-level of ground waters. The second one forms under the clay-opal screen un- der the influence of two factors, namely the inflow of deep reduction sulphur compounds (which are transported together with arsenic, antimony and mercury) and the generation of hyd- rogen sulphide as a result of sulphur- and sul- phate reduction. X-ray-amorphous phase of orpi- ment composition and realgar phase are formed, respectively, on the oxidizing and reductive Barriers.

Jan 1, 1987