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The Golden Cross mine is situated in a sensitive environmental setting on the North Island of New Zealand, about 150 kilometres south-east of Auckland and about 8 kilometres NW of Waihi. The mine is situated in dipping topography, with volcanic ashes making up soils, fault zones running through the area, and rainfall of about 3 m per year on average. Water management is the most demanding environmental challenge on site, and a comprehensive programme has been put in place to address tailings deposition, long term tailings storage, and water treatment during and after operations.   The tailings impoundment is built with an underdrainage system that collects groundwaters and waters that seep through the impoundment. The embankment and impoundment are both built to withstand the Maximum Credible Earthquake and the Probable Maximum Flood. Tailings are treated to remove cyanide and to decrease metal solubility to reduce long term risk to water quality after mining. A state-of-the-art water treatment plant is utilised to treat water from the underdrainage system and water decanted from the top of the tailings pond and stormwaters to remove residual cyanide and metals to extremely high standards with a great deal of reliability and at reasonable cost. Closure of the facility addresses long term post mining water quality issues, and rehabilitation of the area with wildlife habitat as a priority.

Jan 1, 1995

The stability of parallel underground coal mine galleries and pillars have been investigated using two- and three-dimensional (3D) numerical stress analysis. Anisotropic horizontal in situ stresses and the direction of the excavations have been considered in the numerical analysis. The stability of the tunnels driven in a coal seam at various working depths has been investigated taking into account different strata conditions and then results from two- and three-dimensional numerical modelling studies were compared. Maximum principal stress components have been chosen in three various directions: vertical, parallel and perpendicular to the tunnel axis. Analysis have shown that in the anisotropic in situ stress field, the favourable direction of underground mine openings which have different strata conditions depend not only on the horizontal in situ stresses but also on the vertical in situ stresses. Furthermore, 3D numerical modelling studies have been carried out to investigate stability of multiple entry longwall panel gate roads and pillars with various width-to-length ratios (W/L). Results of the modelling studies have shown that the critical dimension of coal pillars depends on their width and the direction of maximum horizontal stresses.

Dec 6, 2010

FOR many years past it has been the practice at the Bairnsdale School of Mines to treat any parcels of auriferous concentrates sent in from the surrounding district by roasting them in a handworked reverberatory, and then chlorinating or cyaniding the product. According to Donald CIark, who has done a large amount of work on these ores, the results obtained were fairly satisfactory extractions of over 90 per cent being claimed. With some modifications, the method has been very generally adopted, not only in Gippsland but throughout Victoria. It is, however, difficult to get exact information as to the extractions actually obtained, and unfortunately no records of working results have been kept at the Bairnsdale School of Mines.Having treated several lots of ore by this method during 1907 and 1908 with unsatisfactory results, the writers thought it desirable to make a detailed investigation on some particular ore, both in the laboratory and on a working scale. The ore selectedwas a parcel of low-grade concentrates from Stirling, a small mining field situated about forty miles to the east of Bairnsdale. This ore was chosen chiefly on account of the heavy and inexplicable volatilization loss which took place even on roasting with the greatest care; the loss amounting to between 10 and 15 per cent. In the experiments here related, three main objects were kept in view:-1. To determine with what mineral 01' minerals the gold and silver were associated...

Jan 1, 1909

Experimentally determined and theoretically explained phenomenon of zonal disintegration of rock around the development working brings about the radical changes in existing ideas about the mechanism of interaction rock massive with engineering constructions.The essence of the phenomenon consists in the fact, that forming of non-elastic deformations zone goes on by way of more intensive deformation and destruction of rock simultaneously in several zones, covering partially or fully output circuit and divided by zones of destructed rock. Under the influence of change of massive strained-deformational condition of depositional rock an accidental deviation of zones of supplementary expansion and compression of rock from the previous positions take place. One can observe multiplicational change of the outline, size and form of all disintegration zones in the time within the area of the working influence at massive. This phenomenon was named "fluctuation of zonal disintegration of sedimentary rock around development working".

Jan 1, 1991

From March to May of 1963, the Bureau of Mineral Resources carried out an experimental aeromagnetic survey at Cobar, New South Wales, to field test a proton-precession magnetometer installation in the Cessna aircraft VH-GEO. The Cobar area was chosen as considerable information was already held on the Earth's magnetic field there, which was known to provide a range of anomalous areas that are not excessively disturbed.A procedure for survey flying and methods for processing data were developed during the survey. Contour maps of the aeromagnetic results were produced in the field. The experimental survey was successful in outlining magnetic anomalies in detail.INTRODUCTIONSince 1951 the Bureau of Mineral Resources, Geology and Geophysics (B.M.R.) has carried out an airborne magnetometer exploration programme with DC.3 aircraft carrying fluxgate magnetometer equipment. Recently a proton-precession magnetometer was developed by the Design and Development Group of the B.M.R. for observatory use. One unit modified for airborne use was installed in the Cessna light aircraft, VH-GEO. The Cessna was modified structurally to take the magnetometer, associated bird, and winch gear.The proton-precession magnetometer has many good features.1. It utilises the transistor and associated solid-state devices in its electronics, and hence is light and small.This is the basic feature allowing its installation in a light aircraft. The transistor circuits have a high reliability factor and owing to the card sub-unit...

Jan 1, 1964

The estimation of the shear stress distribution around an excavation is important to the design of the excavation since shear stresses can generate cracks, loosen grain boundaries or otherwise degrade the mechanical and physical properties of the rock and lead to stability problems. In this study, the distribution of shear stresses in a pillar were back-calculated from the deformation measurements made from the SPDV (Site and Preliminary Design Validation) area at the Waste Isolation Pilot Plant (WIPP) site. A plausible pattern of shear stress around an excavation has been suggested based on the Zero Strain Boundary (ZSB) calculation, computer simulation using FLAC, and back-calculation using measured deformation rates in the pillars.

Jan 1, 1998

Reason Analysis of Impurity Containing and Technology Discussion of Quality Improvement for Low-Quality Iron Concentrate

Sep 13, 2010

A geologic, petrographic and geochemical study has been performed on the pyroclastic flow deposits in the coastal area of East Zhejiang Province, Southeast China. This study leads to classification of the pyroclastic flow deposits into three associations: the extrusive type, the surge type and the ash flow type welded tuff associations. Through detailed investigation and comparison of the characteristics of these lithologic associations, with emphasis on the welded tuffs, a comprehensive model has been proposed to demonstrate the petrogenesis of the pyroclastic flow deposits.

Jan 1, 1995

By R Shaw, R Williamson

Global iron ore demand, sparked by ChinaÆs rapid industrialisation and emergence as the worldÆs newest steel market, has seen iron ore groups investing heavily in production capacity as well as infrastructure. The success of these new projects depends heavily on reliability, competitiveness and quality control in an increasingly demanding trading environment. Furthermore, the iron ore industry continues to improve its competitiveness in mining practices, technology innovation and management processes. The continued fine tuning of these sectors will be critical to the success of the industry in the years ahead, and this mining sector will continue to demand process improvements from their service suppliers to maintain competitiveness. Automation offers a real solution to these demands. A crucial quality control element in mining, beneficiation, stockpiling and shipping stages is ensuring representative samples of ore are taken along each step of the process. When these samples reach the laboratory it is imperative that the sample is representative of the entire stream and that no induced errors occur. Examples of automation start with mechanical primary and secondary samplers in the run-of-mine processes through to sample tower and laboratory crushers, dividers and collectors. Automation is widely used in many forms to provide reliable and repeatable samples for analysis whilst providing a safer working environment. Laboratory automation systems in use today vary from simple linear systems to sophisticated robotic cells. Sample automation in the iron ore industry has resulted in many benefits for both producers and their customers. The most significant benefits have come in the form of higher safety standards whilst reducing sample error, sample handling and sample contamination during collection. These benefits have been further augmented by reliability and repeatability of automating the final sample preparation and analysis stage. Today these benefits are reflected in reduced costs of sampling and improvement in both turnaround time and quality of results, whilst complying with Australian safety and ISO sampling standards.

Jan 1, 2007

By Whang K, Choi H

A study of flocculation of ultra-fine coal particles by ultrasonic waves was investigated on a laboratory scale.The coal suspension was dilute, with low ionic strength, and at pH 6·2.When a stationary sonic wave is set up in a solution containing suspended coal particles, it is believed that high and low pressure regions are alternately established at the half wave-length of the sonic wave and this resultsin the migration of coal particles towards the low pressure regions.As expected the flocculation is more effective as to frequency and the power of the ultrasonic waves is increased.The shape and size of the test equipment are also important variables.

Jan 1, 1977

By J D. St George

In this paper a laboratory investigation into the effect of confining stress, water content and gas desorption on coal permeability is presented. Of major significance is the effect of coal permeability on outburst occurrence and methane production, which is influenced by changes in stress. Test results indicated that the shrinkage of the coal matrix associated with desorption is greater than the coal matrix compressibility which will cause a reduction in the effective stress, hence increasing coal permeability.

Jan 1, 1998

Platiniferous horizons such as the Merensky Reef that are mined chiefly for their PGE contents constitute one end member of a continuum of Ni-Cu-PGE sulfide deposits; Ni-(Cu) sulfide deposits in which the PGE may or may not be by-products represent the other end of this continuum. Although it has long been thought that PGE-rich sulfides can only be developed by magma mixing in large magma chambers, new PGE data for the Bushveld Complex suggests an alternate model to account for origin of mineralization in the worldÆs most important Pt producer. Briefly, this model suggests that PGE-rich sulfides were initially deposited at depth below the Bushveld Complex as a result of interaction of a S-undersaturated mantle magma with S-rich crustal rocks. These PGE-rich sulfides were subsequently re-dissolved by a second magma, which introduced the PGE into the Bushveld Complex magma chamber, where the PGE-rich reefs were formed due to cooling of these magmas. If this model is correct, it means that large layered mafic/ultramafic intrusions are not a prerequisite for the formation of economic PGE-rich deposits. Exploration for Merensky Reef-type PGE deposits can be greatly facilitated by documenting variations in the background PGE contents of non-mineralized rocks collected on traverses across mafic/ultramafic intrusions; the mineralized horizons occur at cross-overs in ratios such as Pd/Cu, Pd/Se and Pd/S.

Jan 1, 2002

By G Smart, D Ward, J Grace

Ridgeway Gold Mine is part of Cadia Valley Operations which is wholly owned and managed by Newcrest Mining Limited. It is an underground sublevel cave (SLC) operation mining approximately 5 Mt per annum. Ore control systems at Ridgeway have been designed to deliver gold and copper metal production through focussing on the ore characteristics that impact on mine and mill performance and ultimately metal delivery. This is achieved using data collection and management systems which allow data to be collected digitally with æat captureÆ validation routines. These data form the basis for forecasting and on-going systems analysis which aim to accurately assess local in situ and drawn ore characteristics. Physical attributes of ore such as draw characteristics, brow conditions, visual grade estimates and draw point sampling are routinely recorded. Ore tracking and accounting systems monitor gold and copper grades, copper mineralogy, host lithology and ore sizing. These factors have material impacts on concentrator throughput and metal recovery. Draw point recovered grades are routinely reconciled back to design data to monitor and assess draw performance. Statistical variance controls are also employed to analyse mine and plant performance and guide actions.

Jan 1, 2003

Results of laboratory studies on the flotation of marmatite (zinc sulphide) with new reagents, which were developed to avoid the use of copper sulphate, are presented.Episulphides were chosen as the basis for the reagents because of their reported special chemical affinity for zinc and cadmium. Attempts were made to solubilize and introduce functional groups to episulphides with organic and inorganic acids, ammonia, phenol, aniline, diethylamine, and pyridine. As a class of reagents, the episulphide-amine combination was generally found effective in zinc sulphide flotation to a greater or lesser degree. Best results were obtained with ethylene sulphide-aniline combination. Although anilino-ethyl mercaptan is the reported reaction product of aniline and ethylene sulphide, it was concluded that the effective zinc sulphide flotation with ethylene sulphide-aniline combination is not entirely due to the formation of the mercaptan.The economics of the possible usage of ethylene sulphide-aniline reagent are discussed.

Jan 1, 1974

By G Wyartt

Systems such as Davey Bickford’s Daveytronic® SP blast initiation system and electronic detonators have been an integral part of drill and blast activities in Australia for over a decade, with the significant benefits of electronic blasting well documented. Since 2010 the Multiblast feature has been commercially available, which enables eight individual blast patterns (up to 1500 detonators each) to be blasted in the same firing window. Synchroblast has been in active operation since 2012, which allows a blast of up to 4500 detonators – either as a single blast pattern, or several smaller adjacent blast patterns – to be reliably initiated.Multiblast manages blasts separately but concurrently, allowing all blasts to conduct prefiring checks simultaneously from the firing point utilising only one remote blasting unit. Each blast can be selected and fired individually, in a sequence determined by the operator by scrolling through the colour display. Synchroblast automatically detects the blasting configuration, and manages all detonators as a single blast pattern. This simplifies the design and blasting processes for the mining operation.Multiblast and Synchroblast are routinely employed throughout Australia and globally in both open cut and underground operations, enabling optimal productivity due to increased blast volume and reduced operational downtime associated with blasting events.A number of case studies will be presented in this paper, detailing various mining operations that are consistently blasting in excess of 2500 detonators per blasting event as a part of standard drill and blast operations. Blasts over 3000 detonators are becoming more frequent as mine planning departments adapt to this operational capability and flexibility.CITATION:Wyartt, G, 2017. Multi and Synchroblasting – maximising operational productivity, in Proceedings Iron Ore 2017, pp 631–634 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By N Coplin

Australian Coal Association Research Program (ACARP) project C25073 was proposed by industry stakeholders seeking a potential solution that improves underground air quality and reduces operational costs associated with technology used to control diesel particulate emissions in the underground coal mining environment.The need to protect workers from diesel particulate matter (DPM) has lead the underground coal mining industry to install disposable filter systems on their vehicles. While the disposable filters are efficient at removing significant amounts of DPM, the following major issues have arisen:- high cost of operations; disposable filters cost $A250–300 each and need to be changed at least once per shift resulting in an estimated cost of up to $A164 M/a, in filters alone, to the NSW underground coal mining industry- improper installation, damaged seals and lack of installing a new filter when the old filter is removed; workers are still being exposed to excessive amounts of DPM.The ACARP project successfully demonstrated significant DPM emissions reduction comparable to the incumbent disposable technology on a proof-of-concept wall-flow diesel particulate filter (DPF) system, as well as satisfactory system robustness when assessed using an industry representative test cycle representing operations of a load haul dump (LHD) vehicle typical of that used by the Australian underground coal industry. It was noted in testing that the technology increased modal NO2 formation, but was compliant over typical operational duty cycles.One of the key benefits with the use of a wall-flow DPF system is its tamper-proof design, mitigating the risk of operating unfiltered diesel plant in poorly ventilated areas. Elimination of the need for continual replacement of disposable filters provides significant operational savings estimated to be up to 80 per cent of the incumbent technology.In addition to the above, the project also delivered a number of significant contributions to the knowledgebase of the Australian and international coal industry with regard to the characterisation of operations and control of emissions.CITATION:Coplin, N, 2017. Wall-flow type diesel particulate filter system to replace existing wet element filter systems used in typical LHDs in underground coal operations, in Proceedings Australian Mine Vent Conference 2017, pp 119–128 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By A R. Proudman, A H. Purvis

The Granites Gold Mine Callie gold deposit is located 550 km northwest of Alice Springs in the Tanami Desert. Gold mineralisation occurs due to a complex interplay of geological factors which include but are not limited to favourable lithology, structure, alteration and quartz veining. High-grade mineralisation, while pervasive under favourable conditions, is highly variable over short distances and is very nuggetty. In contrast, the lithology and geological structures that host the mineralisation are very continuous. Orebody modelling techniques have evolved over time because of a growing understanding of the mineralisation controls. Modelling issues such as sampling and assaying accuracy, modelling method, data density, gold population statistics, geological interpretation and domaining, grade boundary and calculation conditions, and model block size are constantly being reassessed in an effort to increase understanding of the mineralisation controls and modelling accuracy. The evolution of the modelling process in response to increasing data levels and a growing understanding of the mineralisation controls has resulted in changes to the perception of the orebody size and style. This has caused the choice of underground mining method to be revised several times and the process to final mining method selection to take longer than usual. In order to achieve the planned production start-up date of July 1998 the process has been allowed to progress in parallel with development of the underground mine. This paper describes the resource modelling and mining method selection process applied to the Callie underground mine and some of the issues which have contributed to its evolution. Some conclusions that are relevant to the efficient planning and development of new mining projects in general are presented.

Jan 1, 1998

By D O. Hayba

Metal-rich slurries discharged from excess-enthalpy geothermal wells at Kawerau (NZ) indicate that an efficient ore precipitation mechanism operates in some feedzones. In our conceptual model, which takes into account the relative permeabilities of liquid and gas phases in boiling fluids, a metal-precipitating liquid phase is effectively immobilised along boiling fronts, leading to the formation of highly concentrated ore. Chemical equilibrium and heat/mass transport modelling demonstrate the general applicability of this conceptual model to hydrothermal eruption environments.

Jan 1, 1995

By W T. C Kendall, H D. Ngo

Garden Well is a shear-hosted Archaean orogenic gold deposit located 100 km north of Laverton, Western Australia. The Garden Well processing plant is designed for a nominal 491 t/h milling rate and annual capacity of 4 Mt. The plant has three key innovations:1. a scrubbing circuit, expected to reduce grinding power consumption by up to 20 per cent2. a secondary cycloning/gravity circuit, providing a second opportunity for gravity gold recovery (additionally, the circuit effectively increases the leach residence time of the coarse gold bearing fraction of the leach feed by approximately 60 per cent, without any additional tankage)3. the use of mid-stream oxygenation to enhance gold recovery.The Garden Well deposit is free-milling with overall laboratory gravity/leach gold recoveries exceeding 95 per cent at a P80 grind size of 150 ¦m. Three mineralogical domains have been identified: oxide, transition and fresh, with the fresh domain having subdomains of fresh ultramafic and fresh shale. There is a high component of gravity recoverable gold in all three domains.This paper will discuss these innovations and the design challenges and the risk mitigation strategies that were adopted to ameliorate the prototyping risk. The performance of the plant since commissioning together with lessons for the future will also be presented.CITATION:Smith, R J, Kendall, W T C and Ngo, H D, 2013. Treatment plant innovation at Garden Well, in Proceedings World Gold 2013 , pp 315-324 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By K White, R Hardie, J Merritt, B Kirsch, R Lucas

Constructed stream diversions are a common element of mine sites across Australia. A review of constructed stream diversion performance in the Bowen Basin funded by the Australian Coal Association Research Program (ACARP) in 1999 found over 80 per cent of constructed stream diversions failed to meet regulator and operator expectations. Since that time, improvements have been made in the assessment, design, monitoring and management of constructed stream diversions. Fundamental to these improvements has been the development of a better understanding of the regional stream systems and efforts to replicate the natural stream processes in the function and operation of constructed stream diversions.This paper discusses the history of constructed stream diversions through the Bowen Basin in central Queensland recorded in the outcomes of a series of ACARP funded research projects. Further, the paper reports on the outcomes of a current ACARP funded project that has reviewed the success or otherwise of constructed stream diversions in the region. The assessment has compared the performance of diversions that have been designed to replicate and provide for ongoing stream geomorphic processes with those diversions that were designed and built prior to the development of these design improvements. Based on these investigations we have identified design and construction successes and issues requiring further research and management attention.CITATION:White, K, Lucas, R, Hardie, R, Merritt, J and Kirsch, B, 2013. Challenges and opportunities for constructed stream diversions in the Bowen Basin, Central Queensland, in Proceedings Water in Mining 2013 , pp 73-82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013