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By M D. Goodz

MacPhersons Reward gold deposit is in a post-kinematic tonalite intrusion which is a setting different from many other deposits of the Coolgardie goldfield that are hosted in early Archaean tholeiitic sills or meta-sedimentary rocks. Gold mineralisation at MacPhersons Reward consists of auriferous quartz veins that are best developed in the tonalite but extend to the adjacent komatiitic rocks and along the lithological contact zones. The gold-related alteration halo is dominated by biotite-chlorite and pyrrhotite. Unlike many other Coolgardie deposits, the As concentrations are low.

Aug 22, 2011

By McLennan T, Howells E, Zastawny H, Watt J. S

Nuclear techniques have been used to determine the solids weight fraction (W) and ash content of (fine) coal in slurries independent of voidage variations. The method is based on the correlation between W and the hydrogen concentration Hsl (wt/wt) of the slurry. Hsl is determined by combining measurements of neutron moderation and ?-ray transmission. Both Wand ash content are determined by combining the above measurements with the ash-sensitive measurement of X-ray backscatter compensated by a measurement of iron K X-ray intensity.The nuclear analysis system, called the SIRO coal slurry gauge, has been proved in a six-week plant trial at the BHP Steelworks washery at Newcastle, NSW. Several probes, each containing a radioisotope source and scintillation detector, were immersed directly into the coal slurry in the feed box upstream from the bank of flotation cells. For 140 samples W, ash and voidage varied in the ranges of 0 to 13 wt percent, 26 to 41 wt per cent and 0 to 4 vol. per cent, respectively. The r.m.s. difference in solids weight fraction, determined by probe measurements and conventional assay, was 0·52 wt per cent. Ash was determined with an r.m.s. difference of 2·0 wt percent in the coal. Better sampling techniques were used in the last half of the plant trial, and r.m.s. differences were 0.35 wt per cent solids and 1·5 wt per cent ash.

Jan 1, 1986

By Black PM, Itaya T

Arc-type volcanic activity has been a major feature of the late Cenozoic geological evolution of the Pacific-Australian plate boundary in the northern New Zealand region. The timelspace distribution patterns of arc-type rocks reflect changes in the nature of the plate boundary as it has evolved. Inception of volcanism began in the north during earliest Miocene times (26 Ma) following ophiolite emplacement and during the next 10 Ma developed into a volcanic arc segment extending south to the present position of the central North Island. The northern part of the arc became extinct about 15 Ma ago, but activity continued in the central (Coromandel) part of the arc until about 5 Ma ago. In late Pliocene and Quaternary times volcanic activity has become concentrated in a northeast trending zone which is collinear with the Tonga-Kermadec Arc.

Jan 1, 1995

By A Teen

An open cast mine on the West Coast of the South Island of New Zealand proposes to remove up to 30 m of overburden to access an ore body neighbouring National Reserve land. Part of the conditions of the mining permit is that no material above natural discharge levels may be released over the Mining Lease boundary onto the adjacent land. In order to meet this requirement, the client has contracted the design and installation of over 2.6 km of high energy dynamic rockfall control barriers. This paper describes how the rockfall hazards were assessed and the rockfall barriers dimensioned. The design involved 2D modelling of over 3000 simulations.   Modelling parameters were calibrated during field trials at a purpose built section of barrier. The resultant energies ranged from 500 to 3000 kJ. The construction phase of the project involved the drilling, anchoring, and installation of certified barriers up to 7 m high in a remote and inhospitable climate with limited machinery access. By exploring best practice in this specialized field of engineering, a novel rockfall hazard mitigation solution was identified.

Jan 1, 2007

By Neill A, O&apos

The City of Kalgoorlie/Boulder is situated approximately 600 kilometres to the east of Perth (Fig. 1), and is the major regional centre of the Eastern Goldfields, supporting a population of approximately 25,000. The formation of Kalgoorlie Consolidated Gold Mines in 1989 brought the existing operat- ing entities adjacent to the city under common ownership and management. The Joint Venturers forming the management company are Homestake Gold of Australia and Gold Mines of Kalgoorlie (a Normandy/Poseidon com- pany). This traditional underground mining centre has been worked since 1893, yielding 40.8 million ounces of gold from ore with an average head grade of 10 grams per tonne. Historically the heart of the operation has been the famous Golden Mile located on the Eastern perimeter of the city, in the area known as Fimiston. The other significant operations that form KCGM are the Mt Percy Open Pit and the Mt Charlotte Underground Operation. KCGM's current production is 520,000 ounces per year, with the com- bined Fimiston operations (open cut and underground) contributing 400,000 ounces. The current expansion will increase production levels by a further 150,000 ounces. Traditionally 98 per cent of gold has been sourced from underground areas, however the recent upsurge of open cut operations is rapidly overturning this historical relationship.

Jan 1, 1991

By J Lyons, M Hasan, D Pepper, C Vadeikis

Processing of large volumes of ultrafine ores has long challenged mineral processing operators because of lower recoveries and increased tailings. This has led to many deposits, or parts of existing deposits, being viewed as uneconomic. As the mining industry can no longer afford to overlook resources that require finer sizes to achieve liberation or result in high tailings losses, the need for technologies to address these issues has increased. Mineral Technologies (MT) worked with a prominent Australian iron ore producer over five years to implement an innovative gravity separation technology for the beneficiation of ultrafine magnetite. The magnetite mineralisation requires a liberation size of <40 μm and selective rejection of ultrafine silica prior to magnetic separation. Through collaboration with the client, MT applied their Lyons Feed Control Unit (LFCU) technology for the beneficiation of finely grained magnetite. LFCUs are widely used in the mineral sands and iron ore gravity plants, and in tailings applications, to recover water and provide constant high density process streams. This project was an extension of knowledge gained from these applications. Test work was conducted on-site, using 1 t/h pilot and 300 kg/hr laboratory scale units. This test work showed that the LFCUs could reject 20 per cent of feed mass to tails whilst recovering >94 per cent of Fe to product. This upgraded the feed from 53.7 per cent Fe and 19.7 per cent SiO2 to 63.8 per cent Fe and 8.8 per cent SiO2. Recovery by size data showed a minimum 88 per cent Fe recovery to product for <8 μm material and up to 98 per cent Fe recovery for the -38+25 μm fraction. The LFCU rejected 70 per cent of <25 μm SiO2. The information obtained from the test work was utilised in the design of the full-scale units which are due for installation at the project site in 2021. This paper outlines the results of this laboratory and pilot scale test work and how the data obtained was used to design the full-sized units.

Nov 8, 2021

A great range of contacting equipment is used in solvent extraction. However, a tower filled with a regular packing offers many advantages in the direct extraction from slurries. A study was made of the flow of a dense slurry through a packed tower in which the continuous phase was kerosene. The grid type packing, which was preferentially wetted by the slurry, had slats inclined at an angle of 30¦, to the horizontal. On the sur- face of the slats there were uniformly spaced longitudinal indentat- ions. These were of a height slightly less than the film thickness and divided the slurry discharging from the bottom of the slats into a number of uniform streams. When slurry entered the tower it was distributed by means of a troughs and weirs type of distributor. Because of the relatively high slurry velocities that occur at the entry region, it was necess- ary to have the distributor and the first two grids above the solvent level. The interface at the bottom of the tower was located at the mid-point of the bottom grid, so that the slurry entered the interface as a continuous film across the full width of the slats. Using the above system, stable flow with low entrainment was achieved at slurry flow rates of 3.4 mis/cm/sec. This would be equivalent to a flow rate of 177 gallons per minute through a tower of cross-section 4 ft 4 in. by 4 ft 10 in., or 1200 tons per day of solids of specific gravity 2.6 when the pulp density was 65 per cent. Previous tests indicated that a total tower height of about 30 ft would be required for a recovery of better than 99 per cent.

Jan 1, 1969

By N B. McCaffrey, V Glenn, C Johns, P D. Erskine, A T. Fletcher

"Underground coal mining is the dominant method of extracting thermal and coking coal in the southern and western coalfields of New South Wales. Monitoring mining-related subsidence forms an important component of environmental impact assessments and subsidence management plans, particularly when there are conflicts between the interests and requirements of mining and environment and community groups. However, there are few specific guidelines for monitoring the impacts of subsidence on terrestrial and aquatic ecosystems, leading to inconsistent policy approaches and highly variable abilities of monitoring programs to accurately detect biological change.This paper highlights the use of a conceptual framework to guide the development of a long-term ecological monitoring program at an underground coalmine in the Western Blue Mountains, New South Wales. Two pilot studies are described: determining the level of observer agreement to assess the condition of a vulnerable tree species (Capertee Stringybark) comparing field sampling methods for detecting a rare heath shrub, Epacris muelleri, using a power analysis to determine sampling intensity requirements.These examples demonstrate that investment in initial pilot studies to test different monitoring approaches can have long-term benefits for stakeholders by more confidently being able to detect potential impacts.CITATION:McCaffrey, N?B,?Glenn, V, Erskine, P?D, Johns,?C?and Fletcher, A?T, 2014. Detecting long-term ecological impacts of subsidence from underground coal mining – a tale of two pilot tests, in Proceedings Life-of-Mine 2014, pp 139–152 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 16, 2014

By Abishev D. N, Balakirev V. F, Davydov G. I

The problem of recovery of cobalt products from poorly oxidised nickel ores (Kempirsaisk deposit) and pyrite concentrates with a low content of cobalt (Sokolovsk-Sarbaisky deposit) has not been solved to the present time in Kazakstan. The balance reserves of nickel ore of the Kempirsaisky deposit make up more than 35 million tons with a nickel content of 1.13 per cent and cobalt content of 0.05 per cent; besides there are 110 millions tons of out-balance ores (Anon, 1995). In a tailing dump of Sokolovsk-Sarbaisk Mining and Productional Association more than 320 million tons of tailings of wet magnetic separation have accumulated, which contain 7.2 per cent of sulphur, 0.022 per cent of cobalt, 0.012 per cent of nickel, 0.094 per cent of copper, 0.079 per cent of zinc, 16.45 per cent of iron, and from which a high quality pyrite concentrate car) he separated through flotation, containing 48 - 50 per cent of sulphur, 44.15 per cent of iron, 0.141 per cent of cobalt, 0.07 per cent of nickel, and 0.10 per cent of copper. The well-known technological flow charts for cobalt and nickel recovery from the tailings of sulphide-magnetite ores dressing (to give pyrite concentrate) and from oxidised nickel ores, are not profitable at the existing prices for metals, but are not worthless and require significant capital investments for the realisation of their value. The flow chart `sulphate roasting - leaching - solution processing&apos; is used widely for combined processing of cobalt-containing pyrite ores and concentrates.

Jan 1, 1996

By Thomson I. R R, Friday R. G, Palmer W. T

The paper introduces the problems encountered in designing open stopes and briefly examines the factors that determine the final stope dimensions achieved after mining is completed. A case study is presented where monitoring of a stope was considered necessary due to the expected formation of a highly stressed crown pillar above the stope. The influence, on the mining approach adopted, of a yielding crown pillar is discussed. Monitoring and numerical modelling were used to develop an understanding of the behaviour of the particular stope as mining progressed. A comparison between the measured displacements and the numerical predictions at an interim stage of mining was carried out to assist in choosing the final sequences involved in completing the stope.

Jan 1, 1981

By Bhattacharyya A. K

A major constraint on sustaining high rates of production in the collieries of the Southern Coalfield of New South Wales is the inability to develop panels fast enough to match the rates of extraction. This inability is particularly crippling in the case of retreat longwall mining and is due to nearly half the time in roadway drivage being spent on strata control operations such as roof support.Increased rates of roadway drivage and significantly improved roadway stability can be achieved by the application of yield pillars between parallel roadways. These pillars are designed to yield immediately upon formation and transfer the damaging roof loads away from the immediate vicinity of the roadways. Since the width of the yield pillar is the key to their successful application, it was determined through the Yield Pillar Experiment conducted by Kembla Coal and Coke Pty Ltd at West Cliff Colliery.Three experimental headings, each nominally 5.5 m wide and 2.8 m high, were driven to form two tapering pillars. The width of these pillars progressively decreased from 24 m to 3 m over a length of 154 m. The convergence between the roof and floor of the headings measured at various cross-sections corresponding to predetermined widths of the pillars are analysed in this paper to evaluate the stability of the tapering pillars at the different widths.The width of the yield pillar in a three heading development layout at West Cliff Colliery was determined to be 7.5 m.

Jan 1, 1995

The development of reliable and accurate solution sampling systems plus on-line atomic absorption spectrophotometers and voltammetric analysers at Pasminco Metals - EZ&apos;s (PMEZ) zinc refinery at Hobart, Tasmania, has led to extensive implementation of On-Stream Analysis (OSA) throughout the hydrometallurgical circuit. These systems complement industrial autotitrator and colorimetric analysers and with the comprehensive use of a powerful integrated Distributed Control System (DCS), provide extensive monitoring and control of all the important in solution&apos; parameters for the plant. Samples can be left unaltered, or filtered or settled, to remove solids. They are then precision diluted and pneumatically transported to analyser shelters, where they are analysed for zinc, acid, copper, cadmium, lead, antimony, cobalt, nickel, mercury and ferrous, ferric and/or total iron. The range of analyses depends on the sample itself. The results are used for feed forward and/or feedback control of reagents where possible, or simple trend monitoring and out-of-specification alarming when closed loop control is not practical. The overall system reliability and accuracy is such that many daily composite plant samples are no longer analysed off-line. Operator sampling has also been reduced, and in two places, autotitrators with automatic sample pre-treatment have been installed for preparing and analysing samples collected by operators.

Jan 1, 1993

By Harada M, Katsuta S

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

Jan 1, 1987

By D F. Akhmetov, M Yasuike, M Komazaki, Y Kawa

Remote monitoring of geological situation at distant regions with complicated relief, including reliable detection of the rock falls and estimation of the scale of accidents, is of great importance for practical needs. In the paper, vibration data, caused by fall of sample objects and registered by cable sensors, are processed and analysed in order to construct some measure for the indirect evaluation of weight of fallen objects. Nonlinear models, which based on artificial neural networks (ANN), are proposed for the signal presentation. To improve and simplify the learning and classification abilities of the whole system, the aggregative learning method (ALM) is implemented. ALM features relatively low memory and computational resources needed for the procedure realisation, especially for data classification (recall) stage, in compare to conventional methods. The validity and efficiency of the proposed approach are tested through its application for rock fall detection and weight evaluation system using cable sensors and mobile communication network. Classification abilities of the proposed approach are shown useful for estimation of the fallen object weight. Characterised with high computational efficiency and simple decisionmaking procedure, the derived method can be useful for simple and reliable real-time monitoring system design.

Jan 1, 2003

By B Lumsden, R Smiles

Independence Group’s Jaguar Mine treats a polymetallic ore producing a copper concentrate and zinc concentrate. Effective separation of the sulfides requires relatively fine grinding with flotation feed P80 of about 75&#181;m. Zn losses to final tails are greater than 60 per cent and &lt;32 &#181;m. When magnetic conditioning was first installed in 2010 it showed about an 8 per cent reduction of zinc in final tail and on some ores a similar benefit for silver as well. Current testwork is showing about a 12 per cent reduction in zinc and silver in final tail, consistent with the original testwork. Sizing of the final tail during the tests showed that the reduction of zinc and silver losses were only in the &lt;32 &#181;m fraction, as would be expected from an aggregation process. However, the most surprising result was about a 4 per cent reduction in zinc and silver in the plant feed with a &gt;99 per cent statistical certainty. The reduction in zinc and silver in the feed is also only in the &lt;32 &#181;m fraction. Therefore, because the magnetic conditioning of Zn flotation feed cannot impact plant ore feed grade the hypothesis is that the magnetic conditioning is reducing the fine mineral from downstream processes, like filtering and thickening, returning to the plant feed in the recycled process water. This hypothesis is consistent with plant observation of dirty concentrate thickener overflow and measurements of solids in the overflow, as well as the average % Zn grade in cyclone overflow that correlates with the magnetic conditioning ON and OFF days. This paper presents these plant test results.CITATION:Smiles, R and Lumsden, B, 2018. Improving fine sulfide mineral recovery in Independence Group’s Jaguar Mine zinc circuit, in Proceedings 14th AusIMM Mill Operators&#39; Conference 2018, pp 433–440 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

This paper outlines the advances made in vacuum filtration as developed by Outomec Process Filters and details the results obtained at a number of Australian installations. The first section of the paper details the technical advances made by the use of ceramic media in vacuum filtration and explains the reasons for the use of the technology. The second part of the paper discusses a number of Australian installations of the ceramic vacuum filter and where possible compares the actual experiences with those predicted from the test work which preceded the installations. The Ceramec Capillary Vacuum Filter is a vacuum disc filter which combines the proven mechanical attributes of a disc filter with exciting new ceramic vacuum technology from Outomec of Finland.

Jan 1, 1991

By I Basson, J A. Miller, M Becker, F C. de Beer, L C. Bam

"Geometallurgy brings together geologists, mine planners and process engineers to extract meaningful mineralogical and textural information from an orebody, with a view to predicting its metallurgical response. Preferably, automated analytical techniques, which provide mineralogical and textural information, should process a large number of samples quickly, relatively inexpensively and reliably. Microfocus X-ray computed tomography (µXCT) is capable of producing 3D volumetric information on texture and mineralogy that satisfies some of these criteria. µXCT has been used extensively to study the porosity and internal pore structure of iron ore pellets as part of downstream processing. It has not been widely applied to earlier mineralogical and textural analysis of unprocessed ore, due to the limited ability of X-rays to penetrate high-density samples. In this contribution, we propose scanning methods to overcome this limitation, thereby facilitating a broader application of µXCT to iron ore resource management.CITATION:Bam, L C, Miller, J A, Becker, M, De Beer, F C and Basson, I, 2016. X-ray Computed Tomography – Determination of Rapid Scanning Parameters for Geometallurgical Analysis of Iron Ore, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 209–220 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By J Salaya, J Kwak, L Keeney, S Dehkhoda

In addition to volatile commodity prices influencing decision making, in recent years, social and environmental performance have become important decision drivers within the mining industry. There are increased demands from stakeholders, communities, and governments to ensure that raw materials are mined, processed and refined responsibly. The industry also faces the challenge of better managing its waste, which has led to severe consequences when not done properly. The high commodity prices of the late 90s and early 2000s encouraged larger economies of scale and drove mining companies to extract large volumes of rock for separation and concentration at the downstream processes. Over time, as ore grades dropped, the cost of mining escalated and tailings volumes grew. This arduous process also caused strains on recovery cost and performance. Scarcity of water and energy resources coupled with increased production demands and higher operating costs are putting pressure on companies to find innovative ways to increase mining intensities. Hatch’s value chain optimisation methodologies, specifically Grade Engineering® and early waste rejection of the mine, have been of interest to intensify operational performance and minimise waste generation. Enabling preconcentration of the plant throughput, the methodology has significant potential to improve overall metal production and reduce water and energy intensities, whilst minimising wet tailings. Using representative data from real world mines, this paper reports on a case study that evaluates the impact of preconcentration using sensor-based ore sorting on downstream process improvements as well as energy, water and tailings reduction. Financial and economic viability of this technique is presented for both brownfield and greenfield implementation cases. The results show that business case for preconcentration is best when: the distribution of metal in the run of mine ore is negatively skewed and left tailed; mining costs are low; energy, water and tailings management costs are high; and low cost methods of recovering pay metal from low grade material are available.

Nov 10, 2020

By Kellerwessei H, Oberheuser G

A major breakthrough in extending the life of the wear material of high pressure roll crushers when treating moist, highly abrasive material has removed the last impediment to the widespread acceptance of high pressure comminution in the minerals industry. The system is very energy efficient. It has been demonstrated that in the cement industry energy savings of up to 50 per cent have been achieved compared to conventional hall milling. Besides being energy efficient, the process provides some remarkable and useful effects; ò better liberation of mineral constituents (as proven for diamond liberation). ò preferential comminution where induced micro fissures follow grain boundaries. ò higher reactivity of the product due to micro fissures. All these points will be described here together with a review of current flowsheet design and incentives for the use of this method of Comminution.

Jan 1, 1993

Constraints on the mineral industry are best treated as issues that have to be understood and managed in partnership rather than in conflict with communities. The Zapopan development at Mt Todd in Australia and the Martha Hill development at Waihi in New Zealand are but two of many recent successful examples at the local level. However, at the national level, the issues are more complex and more difficult to resolve because the most influential stakeholders are now the urban electorates and governments defer to their perceptions when making decisions and policy.

Jan 1, 1995