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Miners and mineral explorers are concerned at the increasingly hostile environment being generated towards their industry and their profession. There is little official or public recognition that the mining industry is essential for the maintenance of the country's standard of living; a large part of this hostile feeling is caused by the assumption that mining destroys large tracts of our attractive countryside. This paper presents a historic review of the impact on the countryside of the major land using groups commencing with the Polynesian migration. European farming practices, subsequent expansion of the urban dweller and the land management practices of the two Government Departments, Lands and Survey and New Zealand Forest Service who between them control half of the total land area, are discussed. Estimates of total land area to date, directly and indirectly affected by mining have been calculated and a broad estimate of 18 000 ha or 1/1500 of total land area is indicated; current annual mineral production requires some 240 ha. These gross areas take no account of subsequent land rehabilitation, its improvement upon the original in some cases and the recreational, historic and aesthetic areas gained. Comparisons are then drawn with some current land practices in New Zealand.

Jan 1, 1977

By Littlewood E

We offer these notes as a practical contribution. All the arguments we advance have been tested by practical experience.In its preparation we realised that our subject was one of such importance and covered so wide a field that, dealt with by one of us alone, it might easily have been too much for him, so we have endeavoured, by mutual criticism and advice and a pooling of ideas, to bring forward a few points that may be of advantage to members. If any of the paper is of benefit to mining on the "Golden Mile," or elsewhere, we shall feel amply repaid for our efforts.It is obvious to all that the longer the machine is working productively per shift the greater the return, to all concerned; the machine-man himself and the company. Furthermore, if a man commences a shift with a definite objective in view; for instance, to bore and fire a specific cut, which he recognizes will give him a good financial return, then that man will exercise all his capabilities to attain that objective.In this paper we hope to demonstrate the value to the machine-man of the knowledge of the capabilities of each hole he bores, so that he will be enabled to utilize his drilling time to the greatest advantage. Also, we hope to show that such drilling time can be advantageously extended.After the war, with the influx of new men to the industry, some education on the finer points of machine work may be desirable, and any instruction in this branch must stress the realization of the value of each hole.We realise that most of those present have a sound workable knowledge of machine-mining, and we are not trying to teach anyone the fundamentals of machine work, but we would like to bring to their attentIon some of the finer points which we believe are very important.The machine-man has control of gear of a capital value of over £150, and the use or misuse of that material has a direct bearing on working costs. Therefore it is imperative that the capital outlay is gainfully employed.A "bogger" in charge of a 5/- shovel engaged unproductively is bad enough. How much worse for £150 worth of gear to be not fully productive.Figs. 1 and 2 demonstrate angles of break, and the full realization of the importance of this angle is essential to our paper. Although these Sketches are two-dimensional, we hope they will be sufficient to demonstrate our meaning. We will pass over them as briefly as possible.Fig. 1 shows three holes asked to perform an identical task.(a) 7-ft. hole bored 2 ft. into solid ground-will not come out.(b) 4-ft. hole bored 1 ft. from solid ground-will come out easily.(c) 5-ft. hole bored to solid ground-the best that can be expected under general conditions encountered.The angle of break is a right-angle, normal to direction of hole.

Jan 1, 1944

By Weller KR

A study of high pressure rolls grinding of a number of Australian ores and minerals has been carried out using a pilot-scale machine with rolls 300 mm diameter and 70 mm wide. The results from this study have been used in conjunction with plant survey data to construct computer simulation models of various comminution circuits and these have been used to investigate options for incorporating high pressure grinding rolls into these comminution circuits. Possible rolls options for three of these circuits are presented, and likely energy savings over the existing circuits are discussed together with potential improvements in plant throughput and/or product sizing. A scale-up procedure for predicting full-scale machine performance from small-scale testing is described, and the effects of rolls operating conditions are also discussed.

Jan 1, 1991

Expansion of the B.H.P. Co. Ltd. mater ials handling facilities, at their Newcastle Steelworks, began in 1964 and continued until 1970. The present complex handles the annual iron ore requirement of some three million tons for the Sinter Plant and Blast Furnaces. Iron ore is discharged from ore carriers and conveyed at rates up to 3,000 t.p.h. to either of two 180,000 ton capacity storage yards, where it is blended using boom stackers. Material is reclaimed from these yards at rates up to 1,000 t.p.h. using a slewing boom bucket-wheel reclaimer and fed to a screening station. Oversize material is scalped out and crushed in a closed circuit cone crusher. Undersize material is sized on double-deck vibratory screens which separate at 1/4in (6mm). The two fractions are blended in two of four 70,000 ton capacity blending yards using slewing boom travelling stackers. Bridge-mounted bucket-wheel reclaimers reclaim the blended piles at 1,000 t.p.h. Fine ore is conveyed to the Sinter Plant and lump ore to a second screening station, for rescreening, before passing to the Blast Furnace.

Jan 1, 1972

By J Zhou, D M. Hunter, S M. Iveson, K P. Galvin

The recovery and concentration of ultra-fine iron ore can provide significant economic benefits. Presently, there are limited options available given the low settling rates achieved by conventional gravity separation and the relatively poor performance of reverse flotation. The Reflux Classifier is a new water-based gravity separation technology that consists of a set of parallel inclined channels positioned above a vertical fluidised section. This arrangement promotes a powerful throughput advantage compared to conventional fluidisation and a highly selective hydrodynamic basis for achieving sharp separations. A high shear rate develops within the inclined channels, which generates sufficient hydrodynamic lift to convey the lower-density particles (even if they are relatively coarse) to overflow while retaining the high-density particles (even those that are ultra-fine) for discharge to the underflow. The technology has previously been used around the world on particle sizes in excess of 0.1 mm. The present work, however, is concerned with density-based separations down to much finer particle sizes approaching 0.01 mm.A major advantage of the Reflux Classifier technology is the achievement of simultaneous gravity separation and desliming via a single-stage separation. A series of continuous experiments was conducted using an iron ore feed with head grade of 35 wt per cent FeT and nominal top size of 0.106 mm, with 59 wt per cent being below 0.038 mm in size. At a low throughput of 1.5 t/(m2 h), the Reflux Classifier produced high-grade products at a high recovery. For the entire feed, grades of 66.1 wt per cent FeT with Fe recoveries of 80 per cent were achieved in a single-stage separation. Within the 0.020–0.038 mm size fraction, grades of 68.8 per cent were achieved with iron recoveries of 94.7 per cent. Excellent recoveries of up to 57.0 per cent were achieved for the -0.020 mm size fraction. The ability of the inclined channels to retain the fine dense material further enhances the effectiveness of the Reflux Classifier by creating an autogenous dense medium effect within the vertical section. This helps to elevate large gangue particles up into the overflow.CITATION:Hunter, D M, Zhou, J, Iveson, S M and Galvin, K P, 2015. Gravity separation of ultra-fine iron ore in the reflux classifier, in Proceedings Iron Ore 2015, pp 143–148 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By Wickham P, Raeburn M. R

The design and development of slurry sampling equipment for the Mount Isa Mines Limited on stream analysis installations is discussed in detail. Emphasis is given to the critical areas of slurry transport, screen design, pump selection, elimination of fast wearing components and maintenance reduction. Sample point design to fulfil the specific accuracy requirements for On Stream Analysis (3% to 10% relative) is discussed.

Jan 1, 1976

By Corbett GJ, Leach TM

The Nena Cu-Au high sulphidation deposit has formed within the Frieda River Intrusive Complex in association with a major dilatant structure. Multiple intermediate intrusives of Miocene age are localised by a splay (Frieda Fault) of the Fiak-Leonard-Schultz Thrust, a several hundred kilometre long structure, formed parallel to the accretionary prism of northern Papua New Guinea.The high sulphidation systems including Nena, crop out as narrow silica-alunite ridges extending for up to 5-6km in length within a dilational structural environment. Alteration at Mena exhibits two phases of hydro-thermal activity: an initial stage, inferred to be volatile-rich, which has produced zoned alteration; and a later phase, postulated to have been a liquid-dominated fluid, which has brecciated earlier alteration zones and deposited gangue phases as well as Cu/Au-bearinq sulphides in open spaces.

Jan 1, 1994

The invitation to speak today was in the form of a single sentence instruction: How does your company run and how do you communicate from top to bottom? It looks like I'll have to let you into our little secret. The team at Croesus know what works for us but we've never talked about it with others - least of all presented it at a conference such as this. In fact we tend to avoid the jargon normally associated with Best Practice or TQM, however in our own way, each of our staff are 100 per cent loyal to our company's aim to maintain and strengthen our commercial success. Just how we achieve this at Croesus is the subject of this presentation today, but first a little history. My dear old grandfather arrived in Kalgoorlie, as a mining engineer 100 years ago. Do you think he would have chuckled if someone suggested to him that a hundred years later we would just be starting to understand Kalgoorlie's geological mysteries? Well, here we are 100 years later and Croesus Mining is fortunate to be part of a generation now realising the true potential of Kalgoorlie's Goldfields. This provides us with a very fertile field in which to sow the seeds we can obtain from the World's Best Practice in Mining and Processing. With each new mineral deposit being discovered, old theories are being exploded. Each new deposit has a personality of its own, leading to some belated pioneering theories of where to drill next, and how to reduce internal costs so that we can win the war against constantly increasing external costs. What we have now and what the old timers didn't have is a huge database of geological input spanning several gold booms and a couple of nickel booms. My only interest in history is to pick up the points that may help us for our future. This is what we are doing in our company which is something of a David, in the David to Goliath range of mining companies in Australia. As a humbling thought; of the 115 164 tonnes of gold that the world's mines have produced throughout history, four tonnes have been produced by Croesus Mining. That's equivalent to 0.003 per cent of the total world's gold production. In the past financial year we achieved a dividend yield of five per cent. To put this into perspective, that's over twice the dividend yield of BHP, Australia's largest company. As we are somewhat less known than BHP, let me spend a few moments giving some particulars of our company's background.

Jan 1, 1995

By H Hy÷tyniemi

In this paper multivariate data analysis performed on a new multi-camera system implemented to zinc flotation circuit of PyhSsalmi mine is presented. Image-analysis-based system was developed to take advantage of the commonly known fact that the changes in the flotation process are reflected to the visual appearance of the froth surface. Most often the changes are seen first in the froth and later in other process measurements. The image variables are already utilised in closed loop control and considerable savings are achieved with the current setting, but the results coming from the separate cells are used individually. This is clearly not the optimal way to take advantage of the many measurements coming from different locations of the process. A better approach would be for example to use the measurements coming from the early stages of the process to predict the behaviour (or improve the quality of measurements) in the later stages. The methods described in this paper are aimed to improving the situation in this sense.

Jan 1, 2005

By D J. Brake

In most underground mines, the ventilation system is a significant portion of the total mine capital and operating cost and the largest consumer of underground electrical power. The effectiveness of the ventilation system has a major bearing on the safety, health, comfort and morale of underground personnel, and has a critical role in meeting production targets and therefore business revenue. Perhaps the most important component of the primary ventilation system is the primary fan. Correct performance testing of the primary fan during the warranty period is important not only to ensure the mine has obtained the asset that it paid for and can therefore deliver on the fanÆs crucial safety and economic role in the future of the mine, and to provide a justification for releasing final performance warranty payments to the supplier, but also to provide a benchmark or baseline against which to assess future performance issues. As there are at least three potential international standards available to measure fan performance, there has been considerable confusion regarding which of these to use for testing primary mine fans, and also the correct allowances and tolerances to use. This paper provides guidance on which standards to use for different applications, how the standards should be interpreted, what allowances and tolerances are reasonable, and other important issues to be resolved with the fan supplier prior to making a contract award. The paper also discusses practical issues and methodology for in situ primary fan performance testing.CITATION:Brake, D J, 2013. Performance and acceptance testing of main mine ventilation fans, in Proceedings The Australian Mine Ventilation Conference , pp 141-148 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By M Ahmed

Reliable face support pressure is necessary for shield driven tunnels in cohesionless soils to prevent excessive ground movements. This paper presents experimental work on stability of a tunnel face using transparent soil models aiming to obtain magnitude of tunnel face minimum supporting pressure, failure pattern and extension of failed zone. A model tunnel was preinstalled in transparent soil which was supported at the face by means of water pressure. Tests were performed by reducing supporting pressure until collapse occurred. Model tests were sliced optically with laser sheet and images were captured for every decrement in tunnel supporting pressure. Later, these images were analysed by digital image correlation (DIC) and vector fi elds of incremental displacements were obtained. Values of minimum support pressures were given for different cover/diameter (C/D) ratios. Geometry of the failure zones depicted for different (C/D) values and appeared to be of chimney shape with a limited extension front of the face. A minimum support pressure was achieved with support pressures as low as 10 ± 1 per cent of the effective vertical stress at the tunnel axis. The stability of the tunnel face was related to the coefficient of active earth pressure with C/D ratio having a small effect on the magnitude of required pressure at collapse. In general, results of the study were in agreement with current knowledge of full-scale situations.

Mar 8, 2011

By Nicol SK, Engel MD

Ion flotation involves the adsorption of ionic species, in association with surfactant molecules, at the surface of rising gas bubbles, for the purpose of recovering and concentrating those ions. The objective of this study was to optimise the ion flotation process using a heap-leach liquor, containing gold cyanide, and the surfactant cetyl trimethyl ammonium bromide (CTAB). The aim was to minimise the surfactant reagent dose, maximise the throughput of feed liquor in the process, and satisfy the dual constraints of a high gold recovery and a high volume reduction factor. Development of a first order model of the ion flotation process formed the theoretical basis for the test program procedure and the interpretation of the results. Batch tests were used in order to determine the ultimate recovery curve for the heap leach liquor-CTAB surfactant system. The results indicated that a surfactant dose of about 0.083 g/l would be necessary in order to achieve a satisfactory gold recovery. Continuous tests were then performed on a small-scale pilot plant at the Newcastle Laboratories. The optimum result achieved was a gold recovery of 85 per cent, a volume reduction factor of ten, and a feed throughput of 2.3 m3/m2-h. Recent work also indicates that very much higher volume reductions can be achieved using a larger diameter vessel. The improvement may be a consequence of a reduction in wall effects and hence an improvement in foam drainage.

Jan 1, 1993

The past decade hap seen revolutionary advances in com-munications and information-handling techniques which have been stiriulated by "cold war" military requirements and by, current programmes for probing into outer space: The tools used in exploration for petroleum and minerals have been improved significantly as a result of this new space age technology and even greater improvements are on the way.Two areas of technical activity have been particularly fruitful in enhancing the effectiveness of exploration, methods. These are (1) The development of new approaches, based on information theory, for extracting signal from noise more efficiently than before, and (2) The use of high-speed digital computers for storing and processing all kinds of exploration information, not only geophysical but geological as well.In seismic prospecting, use of information theory has led to new techniques such as time-domain filtering, wave-number filtering and correlation methods which have made it possible to obtain usable reflection data from areas which were previously considered NR. Complex playback and other data processing facilities have been developed to apply these approaches.

Jan 1, 1963

Conventional narrow vein mining, utilising hand held methods, is expensive and requires specialised miners who are becoming a rarity. Hand held mining techniques (shrinkage stoping, leading stoping and cut and fill) have the advantage that they can be selective. The methods allow continued sampling of the face, control of hanging wall conditions and are adaptable to changes in strike and dip. On the other hand, more productive longhole stoping methods can allow excessive dilution due to drill hole deviations and changes in orebody dip and can be subject to unexpected hanging wall or footwall failures. Development of small scale equipment (as narrow as 0.8m wide) used for drilling or bogging very smallaccess drives has been ongoing over the past decade. In this paper, types of equipment are examined and compared, particularly with respect to their produc- tivity, size, and working environment. The introduction of electric hydraulic equipment has provided a better working environment with reduced noise, exhaust fumes and heat. The concept of the "hydraulic cherry picker" may have application in mining steeply dipping orebodies. The system requires orebodies to be reasonably consistent in dip over 15 metre sub-level intervals. The system involves the basic concept and skills of machine and airleg mining, combined with the safety and productivity of a mechanized work platform. The platform or basket is stabilized between the hanging wall and foot- wall by hydraulic rams and is extended by a tilting hydraulic boom mounted to a small prime mover or trailer. Design concepts (including remote controlled charging of explosives, adaptation to the boom for rock cutting and the overall electric hydraulic mining concept) are put forward in the paper as a view as to how narrow vein mines will be mined in the future.

Jan 1, 1987

Comalco Limited has recently completed construction of a $50 million kaolin plant at the site of its bauxite mining and industrial minerals operations at Weipa. The plant will produce 100,000 tonnes per annum of coating grade kaolin for the paper industry.Comalco produced the first coating kaolin from the deposit in 1979 on a trial basis. Since then a variety of quality coating grades with specific particle ize distributions and brightness values have been prepared.Extensive drilling and bulk sampling of the deposit over eight years has shown that the orebody is large and of a high grade suitable for the production of premium quality coating kaolins.The processing plant technology was developed by Comalco in association with the European kaolin and equipment producer Amberger Kaolinwerke GmbH (AKW).The Weipa kaolin plant is the first of this size to be built in the Pacific Basin region and it will offer the region's paper-coating mills a stable and reliable source of high-quality kaolin, shipped from an established bulk loading port. The paper provides an overview of the development of the kaolin investment, the nature of the production process and details the project management procedure used for the design, construction and commissioning of the plant. Three areas of significant interest, the gas turbine fired pray dryer, the moving bridge shiploader and the use of aerobelt conveyors on the project are detailed.

Jan 1, 1988

By A Melkumyan, K Silversides

The banded iron formation-hosted iron ore deposits located in the Hamersley Ranges of Western Australia contain marker shales that are used to distinguish lithology for geological and orebody mapping. These marker shales produce distinctive signatures in the natural gamma downhole logs, which are conventionally manually interpreted. This paper proposes an alternative method of automatically identifying these shales using dynamic time warping (DTW). A Gaussian processes (GPs)-based method for automatic identification is also considered. Both methods are tested on a deposit that contains the Marra Mamba sequence of the Hamersley Province.Both methods were trained to predict the location of the desired shales, and the resulting outputs were compared with a manual interpretation of the results to determine the accuracy. The GP method can identify signatures with an accuracy between 87.0 per cent and 92.0 per cent, which increases to 92.9 per cent and 95.7 per cent where the GP is certain. The DTW method has an accuracy between 90.0 per cent and 91.6 per cent, which increases to 94.0 per cent and 95.4 per cent where the DTW is certain.The GP method has several advantages, including a more automated library building process, a probabilistic output and a shorter run time. However, the DTW method was capable of accepting more distortion in the signature and therefore identified more signatures. This is important in a deposit where the signals are frequently distorted by events such as hydration and folding. Both methods provide a viable alternative to the current manual detection, but their differences make them applicable to different cases.CITATION:Silversides, K and Melkumyan, A, 2014. Comparison between Gaussian processes and dynamic time warping for classification of marker shales in iron ore deposits, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 177–184 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

In dense medium processes for the beneficiation of minerals the consumption of medium (generally ferrosilicon) represents a major component of the operating cost. This provides a strong incentive for improvements in heavy medium recovery circuit design and operation. A major thrust in heavy medium plant design over the past decade has therefore been towards circuits which reduce medium losses. In this paper recent trends in plant design are examined in relation to the factors infl uencing circuit performance and medium losses. Operational details ' which have a significant effect on losses are discussed and illustrated by means of plant and pilot plant test data, with particular emphasis on the performance of wet drum magnetic separators. While the emphasis is on reducing the consumption of the high-cost ferrosilicon medium used in minerals beneficiation, most of the principles described in this paper are equally relevant to the design and operation of magnetite recovery circuits for coal preparation plants.

Jan 1, 1987

The research, development and testing of a Blast Control Plug (U.S. Pat. #4,754,705) funded by the U.S. Department of Energy is described. The plug's function is to improve blasting efficiency through the enhancement of stemming effectiveness and thereby reduce drilling and blasting costs. The plug comprises a solid unit placed in the blast hole within the stemming column above the explosive. It is designed for use with back filled drill cuttings or any other suitable material The research and development program comprised the testing of the plug in small diameter holes in competent rock for both bench and crater blasting configurations and full scale field trials in multiple hole and row blasts using blast holes of from 76 to 387 mm in diameter. Test measurements included stemming displacement and velocity, face movement and extent, peak air over pressure and ground surface peak particle velocity. Data acquisition equipment included a Spin Physics SP2000 high speed video motion analysis system, and acoustic and seismic monitoring units. Substantial reductions in stemming ejection velocity or ejection elimination were achieved whilst reducing stemming length by up to 35% over conventional practice. Peak air blast pressures were also reduced by between 8 and 25 dB. A strong inverse relationship between rock face movement and stemming ejection velocity was found. The implications of the importance of stemming effectiveness in blasting and computer blast simulation is also addressed.

Jan 1, 1990

By G C. Reed, J M. Murray

During more than 100 years continuous mining of the lead-zinc orebody at Broken Hill, an immense amount of geological data has been collected about shear zones related to the orebody. The challenge to current mine geologists is to synthesise and interpret these data sets in a way that is applicable to production demands. Precise knowledge of the locations of major shear zones is important not only for the determination of ground conditions but also to develop an understanding of ore remobilisation along these structures. Traditionally, geological information has been collected from drill core and back and wall mapping underground, and interpreted on sections that are approximately 20 m apart. The recent introduction of MaptekÆs Vulcan software has enabled the shear zones to be modelled in three dimensions. The new three-dimensional shear models have been combined with seismic data from the Southern Cross area. The seismic data is collected from a microseismic monitoring system installed in the Pasminco Southern Operations in August 1996 (Rauert and Tully, 1998). The addition of seismic information to the shear zone models has led to a greater degree of certainty about the shear zone locations and has provided information about shear zones in areas yet to be drilled.

Jan 1, 2000

Universal Resources Ltd has acquired a large portfolio of high quality exploration projects in two of Australia's most prospective regions for base and precious metal exploration: the Mt Isa Inlier (the Mt Isa-Cloncurry area) of North West Queensland, and the southern Lachlan Fold Belt in New South Wales. Drilling techniques commonly employed by the company for mineral exploration include diamond core drilling, air core drilling, reverse circulation (RC) drilling, and rotary air blast (RAB) drilling. Using examples from these two regions, each drilling technique is briefly described and compared, with particular reference to the specific advantages and disadvantages of each method for: sampling size, sample representivity, recovery, integrity and potential contamination. The applicability and implications of the different drilling techniques described for subsequent mineralogical and metallurgical evaluation work are discussed.

Mar 1, 2010