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Underground mechanized excavation in New Zealand has become more commonplace in civil and mining applications during the last three years. At one stage up to seven Dosco Road- header machines were being used on different projects around the country. The Huntly West Mine Drifts inclined at one in four were by far the most severe grade conditions that the machines were subjected to; however, other operations posed their own particular problems for the machines. Two major interrelated factors became evident as soon as the machines commenced at Huntly. These were traction problems on the grade and control of water, particularly on the invert.

Jan 1, 1978

Until 1937, the mining of ore was carried out by conventional methods, using pneumatic drills and standard drill steel. The adoption of the diamond drill, formerly used for exploration work, for blast hole drilling in stopes, was first developed by Noranda Mines Limited, Noranda, Quebec, although it had been used previously in Northern Ontario and Western United States, to remove weak pillars and ore remnants left by conventional methods. Previous to the adoption of the diamond drill method at Noranda, a sub-level benching system of stoping was used. Sub-levels were driven at 35 ft. intervals and the benches drilled off by pneumatic drills using sectional steel. Results were very satisfactory, in sulphide ore, where the drilling was comparatively easy, but in the harder rhyolitestopes the footage drilled per machine-shift was only half of that obtained in the sulphide stopes, and owing to the high gauge loss, there was often difficulty in drilling holes to the required depth. This led to trials with the diamond drill for this type of work. While the cost per foot was more than with sectional steel, an appreciable saving in development work could be made by increasing the sublevel interval from 35 ft. to 60 ft., and stope widths from 60 to 100 ft. This saving, together with the increase in blasting efficiency, resulted in a substantial reduction in overall costs.CONDITIONS FOR SUCCESSFUL APPLICATIONWhile long diamond drill blast-hole mining has widespread application, there are certain conditions which appear to be desirable, if not absolutely necessary, for its successful use.

Jan 1, 1946

By S Yang, J Wang, J G. Ning

A series of conventional dynamic uniaxial compression (CDUC) tests and coupled static-dynamic loading (CSDL) tests were conducted using a split Hopkinson pressure bar (SHPB) system to explore the dynamic mechanical behaviour and fracture characteristics of medium sandstone on a microscale in the laboratory. In the CDUC tests, the dynamic uniaxial compressive strength of the medium sandstone was rate-dependent, while the dynamic elastic modulus was not dependent on the strain rate. Then, we proposed a generalised model to characterise the rate-dependent strength from 17.5 s-1 to 96.8 s-1. In the CSDL tests, with increasing initial pre-static stress, the dynamic elastic modulus and dynamic strength increased nonlinearly at first and then decreased. The results show that two classical mechanical types (ie Class I and Class II) are observed from the dynamic stress-strain responses of the CDUC and CSDL tests. By means of scanning electron microscopy (SEM), the micro difference of post-loading microfracture characteristics in Class I and Class II behaviour was identified. In Class I behaviour, intergranular fracture (IF) usually initiates at or near the grains, most cracks deflected along the grain boundaries, resulting in a sharp angular edge, then coalesces to the main fracture surface that splits the specimen along the direction of stress wave propagation. In contrast, Class II behaviour results from the combined IF and transgranular fracture (TF).

Nov 29, 2022

By Wright J. K

In recent years the production of steel from directly reduced iron ore pellets has ex- panded rapidly. However continued growth will depend on an adequate supply of suitable raw materials for the various commercial gaseous and solid reductant processes now in operation. Al- though at present Australia does not produce pellets primarily for direct reduction, there is an increasing awareness of Australia's potential role as a supplier of high grade ores for export and/or domestic use. The properties and quality requirements of iron ore pellets made specifically for directre- duction (DR) are reviewed and the laboratory techniques and test methods used at the CSIRO Division of Process Technology for the evaluat- ion of potential DR feedstocks are described. At the present time most of the evaluation tests for DR pellets are extensions of those de- signed for existing blast furnace (BF) burdens. In the case of some physical parameters such as cold compression strength, abrasion index and cold strength after reduction this extension is quite satisfactory. In the measurement of para- meters such as reducibility, swelling and stick- ing tendency, however, it is necessary to deve- lop meaningful standardized tests so that ores and pellets can be ranked for DR performance. To do this, data from the laboratory tests and from operating plants must be correlated.

Jan 1, 1980

By Gemmell J. B

Zinc-bearing massive sulphide deposits have been mined in Tasmania since 1900. The current major producers are Hellyer and Rosebery, with total resource tonnages (mined plus reserves) of 16 Mt (million tonnes) and 24.8 Mt respectively. These deposits belong to the class of seafloor volcanic-hosted massive sulphides (VHMS) and are located within the Mt Read Volcanics, a narrow belt of continental margin calcalkaline volcanics of Cambrian age. Compared to other Australian VHMS deposits, and world-wide MVT and Sedex deposits, the Tasmanian examples clearly stand-out due to their high metal grades, averaging over 17 per cent Pb+Zn. The deposits vary in morphology from mound style (Hellyer) to sheet style (Rosebery) with other combinations including stacked lenses (Que River) and disrupted cross-cutting bodies (Hercules). All deposits show the classic VHMS zonation from an Fe-Cu-bearing base to a Zn-Pb-Ba-rich top. Zinc, gold and silver tenor commonly increases toward the stratigraphic top of the deposits. The ores have been deformed during regional metamorphism, resulting in folding, shearing and recrystallisation of sulphide lenses. In addition to the major deposits, a number of small massive sulphide prospects occur throughout the volcanic belt and the potential for the discovery of further large, deeply buried deposits remains high.

Jan 1, 1993

Roof bolting with resin bonded bolts has been developed extensively in French coal mines. There are three aspects of this development: 1. The reason for and the care used in the development of roof bolting from use as a reinforcement in a classical arched roadway to use as the only support in roadways in ad- vance of the working face (the roadway being reinforced behind the face); 2. The problems encountered and studied, such as choice of boltable roadways and determination of the technical data in designing a roof bolting pattern; 3. Only because roof bolting has been controlled by safety rules, and especially by accurate measurement of strata behaviour, has this system of support been expanded aapidly in France since 1967.

Jan 1, 1971

Circulating Air Classification of Manufactured Sand Due to environmental concerns, the supply and use of natural gravel has been limited by the Swedish government. The Swedish concrete industry is therefore examining manufactured sand as an alternative that has equal or better product quality, and which the Swedish quarry industry already has the ability to deliver. However, in order to comply with the specifications set by the concrete industry, a better means of classification is needed, as the proportion of fine particles (filler) smaller than 63 - 125 ¦m in size must be reduced. One classification technology that meets the requirements may be air classification. This paper examines the process of circulating air classification, which is not yet commonly used in the Swedish quarry industry; suggesting that a better understanding of the process is needed. The circulating air classifier in this study has two internal machine parameters that can affect the separation point; namely, the speeds of the circulating fan and the separator fan. We study their effect on the separation point as well as the interaction between these parameters. Full-scale parameter tests are also conducted, in which size distribution is measured before and after the circulating air classification. This study shows how the different parameters affect the separation point and that it is possible to produce manufactured sand according to specifications. Computational fluid dynamics (CFD, Fluent) is used to study the internal flow of the air circulating within the classifier. A single-phase study of the flow field is conducted to support and explain the findings from the full-scale tests.

Sep 13, 2010

THE following brief paper is submitted with a view to encouraging the exploitation of hitherto neglected 10w~ grade ore-bodies which are suitable for extraction by open-cut methods.The Corinthian North mine, situated 10 miles from Southern Cross, in the Yilgarn district of Western Australia, furnishes an example of low working costs, although operations are carried out on quite a limited scale.The body of quartz which is now being worked strikes N.W. and S.E., has a very slight underlie to the west, and lies between bodies of quartz-hrematite s,chist on the east and amphibolite on the west.So far as the property has been explored, it would appear that the underlying sulphide rises to within about 70 ft. of the surface in the northern end of the workings, and pitches away to the south at a grade...

Jan 1, 1915

By J Edman, RáBeamish, G Cambourn, B Beamish

Moist Adiabatic Benchmark (MAB) and R70 testing have been applied to core samples of a multiple seam sequence from a borehole at the Doyles Creek Project. The coal samples range in rank from high volatile B bituminous to high volatile A bituminous, with a general increase in coal rank as depth increases in the borehole. The intrinsic coal reactivity to oxygen decreases with coal rank as indicated by the R70 values. The time taken to reach thermal runaway shown by the MAB testing however is strongly modified by the interaction between the intrinsic coal reactivity, the moisture content of the coal and the retained gas content of the coal. This is clearly demonstrated by the lowermost seam of the sequence. The MAB test for coal from the Whynot Seam took 20 days to go to thermal runaway, which projects to heating issues taking between eight to 12 months to occur for loosely piled coal found in coal roof falls or a longwall goaf and uncompacted stockpiles, assuming sufficient air is available for coal oxidation. The results from this project illustrate leading practice for the operational planning and development of an appropriate spontaneous combustion management plan (SCMP).CITATION:Beamish, B, Cambourn, G, Lewis, G, Edman, J and Beamish, R, 2013. Application of leading practice spontaneous combustion assessment to exploration at the Doyles Creek Project, in Proceedings The Australian Mine Ventilation Conference , pp 293-298 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By Nemcik JA, Gale W. J

The magnitude and orientation of the in situ stressfield has been determined as a key factor in controlling the stability of openings for both coal mine development and extraction. Monitoring of roadway and pillar behaviour in conjunction with numerical analysis has identified specific stress control measures that have been successfully applied to improve productivity in underground coal mining operations. The influence of the major horizontal stressfield on the stability of openings has been identified at a wide range of sites including mines in Australia, Britain, the USA, New Zealand and Japan. Stress mapping, stress measurement and stress monitoring techniques have been applied to define the in situ stress regime and, together with the correlation of measurements of rock deformation and rock reinforcement behaviour, has enabled appropriate stress control measures to be developed. Stress control measures for development headings have required the selection of roadway orientation, roadway sequencing, reinforcement density and pillar size. The monitoring of behaviour at a range of trial sites has confirmed significant improvements in development stability. Stress control measures for longwall extraction have required rational selection of longwall orientation and extraction direction. Where a mine layout design incorporating the optimum longwall layout design has not been possible, the use of sacrificial roadways has been successfully applied to protect key roadways from stress concentration effects. Comprehensive in situ

Jan 1, 1992

A simulation and animation model was constructed for the Stockton Coal Mine. This mine is located in the north western area of the South Island of New Zealand. This model was used to study the optimum size of the stockpile areas whilst achieving the correct product coal qualities. The model evaluated the impact on stockpile size and product coal qualities for both bulk and selective mining. The effect of modifying the amount of known clean coal quality was also investigated. The software used was GPSS/H« for the simulation and Proof Professional« for the animation. From the study, it was recommended to incorporate selective mining in future studies. The shipping plan needed to be modified for a better correlation between coal production levels, in situ coal resources and wash plant capacity.

Dec 6, 2010

By D Skinner, P Haeussler, D Bradley, A Christie

Mesothermal gold deposits of southernAlaska and Westland, New Zealand have both formed at the seaward edge of major collisional zones in the Pacific basin. In Alaska, production of large fluid volumes correlates in time with the addition of heat into the lower parts of the accreted terranes in the late stages of collisional orogeny. This heat was critical for driving both the metamorphic reactions that released the large volumes of fluid that carried the gold, and the contemporaneous widespread anatexis and magmatism. In Alaska's Chugach terrane, this heat as produced by subduction of a spreading ridge beneath the North America continental margin in the Eocene. The resulting products were the S-type granites and gold-bearing veins. The similar widespread S-type plutonism and gold veining in Westland's Buller terrane suggest that a similar tectonic event could have triggered ore formation along the southeastern edge of Gondwanaland. Based on the Alaskan model, a Devonian or Early Carboniferous age is favoured for high volume metamorphogenic fluid generation and gold vein formation in Westland.

Jan 1, 1995

By Gregg PEH, Horne D, Bolan N, Stewart RB

The Tui mine site is situated on the NW flank of Mt. Te Aroha, at approximately 400 m altitude. During underground mining operations two lead-copper-zinc ore bodies were exploited and processed on site. The legacy of the mining operation is a barren dam containing over 100,000 m3 of sulphide-rich tailings. The Tui mine site is arguably the worst case of environmental degradation resulting from past mining activity in New Zealand. Although the impacted area (approximately 4 ha) is extremely small by international standards, acid mine drainage (AMD) emanating from the abandoned tailings dam and mine adits has severely contaminated local streams and prevented natural plant recolonisation of the site for more than 20 years.

Jan 1, 1995

By Lynce AJ

A method has been developed for the prediction 'of 'the- . performance of a multi-stage grinding=cyclone classification circuit of any degree of complexity on any ore for a wide range `of operating conditions, The-.method involves ;the. s` inu ation b'f the circuit on a digital computer by means of. matheinatical' models ":bf the"' individual units:, the. development of which is- also discussed'., At present, in order to establish 'the!'" charac'teristtics of they ¦ore- and the machines. in mathematical terms;. it is necessary to know'the performance of a , simpl,.e. ; system on tri.e ore - for! one known ,,feed rate and.fe.ed s,l-zing, analysis. ' ,Fiiither work on :the- separate identification 'of the terms defining the characteristics of the ore and the machines may permit the method to be, applied directly to the cj.4ta,derived from small scale tests on ores,

Jan 1, 1964

Since 1865 when Congress moved to create a Federal Mining Bureau, successive legislations have given rise to the current '!Federal Coal Mine Health and Safety Act, 1969. Coal beds from 22 feet to 20 feet thick are mined under covers from 50 to 2800 feet with full and partial pillar recovery equally popular and accounting for a total of 54% of the mines. Pillar recovery and roof support practices vary, and each operator must submit an overall roof control plan (within specific guidelines) for approval before undertaking any development. The guidelines relate to dimensions of openings, details of support, sequence of extraction, limits of extraction and caving details. Experienced and professional staff of M.E.S.A. provide roof control plans and make inspections and grant-approvals of principles of support and minimum support in pillar extraction, with provision for modifications with time. Guidance is given with training programmes and standards of supervision. All of these aspects are approached in the spirit of the Congress declaration that the first priority and concern must be the health and safety of the miner.

Jan 1, 1974

The short review of hydrogeologic conditions in the three Polish coal basins have been presented as the background for the prevention measures against water inrushes being underta- ken in coal mines. The Polish mine safety regulations concerning water inrush prevention have been discussed, namely: - classification of sources of the potential water inrushes, - levels of water inrush risk and conditions of mining operation in the mines facing particular risk levels, - determination of the -di.mens.ons.of protecting pillars to prevent water inrush to mines, protection of surface water reservoirs and their earth embankments in regions submitted to mining deformations. Three examples of coal mining being carried out under water bodies have been presented.

Jan 1, 1988

By M D. Raine, J K. Bartlett, S C. Dominy

The Bendigo Goldfield is located in the state of Victoria, Australia, and is one of a number of fields that make up the Central Victorian Goldfield. Since 1993, Bendigo Mining NL has been carrying out an extensive re-evaluation of the goldfield and is currently well advanced in developing an underground mine. The sediment-hosted auriferous quartz reefs are structurally complex and closely associated with anticlinal axes and reverse faulting. The gold within the quartz reefs is characterised by both its coarse nature (100 up to >5000 ¦m) and its erratic distribution; as a result, the Bendigo Goldfield is classed as an extreme nugget effect system. This characteristic ensures that the Bendigo mineralisation is very challenging to sample and evaluate. In this case, diamond drilling is a good measure of structure and geological continuity, but a poor measure of grade and grade distribution. Drilling, combined with on-reef development, bulk sampling and detailed geological studies are required for resource evaluation. For grade control a balance has to be sought between sample representativness, cost, turn around time and practicality. Extreme nugget effect deposits like Bendigo, require the use of bulk samples in order to be representative. However, the cost and turn around time is significant. As a result, a micro-bulk sampling system has been introduced that attempts to overcome these problems by providing a fast, practical method that can define ore from waste. Bulk sampling and on-vein development are still necessary for resource and reserve estimation.

Jan 1, 2003

By Watt JS

The ash content of coal can be determined using radioisotope X-ray techniques. A number of overseas applications of X-ray techniques are described; however these suffer from the disadvantage of either not compensating for iron variations or, if compensation is used, using X-rays of low penetration with consequent sampling difficulties. Current Australian Atomic Energy Commiss- ion (AAEC) research on X-ray techniques is aimed at overcoming the limitations of these methods. The AAEC method involves making measurements proportional to mass absorption coefficients of X-rays in coal at two energies. Calculations and experiments with X-rays up to 35 keV have shown that ash content can be determined to about 1 wt.%. This work is being extended to higher X-ray energies to enable the technique to be used directly on a conveyor belt or in a hopper. Neutron techniques can be used to measure the concentration of specific elements such as carbon, hydrogen and silicon in coal. Their con- centration is correlated to the coal parameters of interest. Methods of moisture determination based on hydrogen measurement and ash determina- tion based on silicon and aluminium measurement are described. Energy content can be determined accurate- ly by analysing the carbon content of coal

Jan 1, 1978

By D J. Williams, A Shokouhi, A Naderian

Extracting alumina from bauxite involves the production of fine-grained waste known as red mud. The highly alkaline red mud is usually neutralised by applying sea water, thickened to between 25% and 30% solids by mass, before disposal to a Tailing Storage Facility (TSF). Hydraulic sorting, settling, self-weight consolidation, and desiccation are the processes contributing to the overall volume change of the red mud after deposition. Investigating the effect of these processes on the volume change behaviour of the fine-grained red mud is an important step in the estimation of the required storage volume of the storage facilities. This paper presents the results of a series of laboratory consolidation tests in a slurry consolidometer, and comparisons are made with field testing and observations.CITATION:Shokouhi, A, Naderian, A and Williams, D J, 2018. Assessing the volume change behaviour of red mud through laboratory and field testing, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 309–316 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

The development of the SECV brown coal open cut at Loy Yang will require depressurisation of aquifers both within and below the coal seam sequence in order to maintain open cut stability. Prediction of future open cut dewatering requirements at Loy Yang Open Cut and evaluation of the regional consequences of dewatering has required development of a detailed hydrogeological model of the Loy Yang area. The complex stratigraphy of the coal seam and aquifer/aquitard sequences at Loy Yang have been analysed and integrated with the hydrogeological concepts developed from regional groundwater studies to formulate a realistic hydrogeological model as a basis for finite-element flow modelling.

Jan 1, 1988