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Since early-2001, Kalgoorlie Consolidated Gold Mines (KCGM) has successfully operated an ultra fine grinding (UFG) circuit to supplement its roaster capacity for the treatment of the refractory gold flotation concentrate. A second UFG mill was installed in 2002 taking the total UFG capacity to over 20 tph while grinding to 11 to 12 microns and achieving over 90 per cent gold recovery. A development program in 2002/3 involving plant trials, pilot plants and laboratory testwork resulted in process improvements and a better understanding of the milling and gold leach processes that assisted in narrowing the gap between UFG and roasting. This paper details the operation of the ultra fine grinding process at KCGM as a non oxidative treatment for the extraction of gold from a refractory ores.

Jan 1, 2003

The Horn Island gold and mineral field produced 194 kilograms of gold in the 4 years subsequent to its discovery in 1894, from an area of shallow workings 1.5 kilometres x 0.5 kilometres. Gold deposits in the adjacent Prince of Wales, Hammond and Possession Islands also drew attention at that time.These islands form part of a Carboniferous sequence of ignimbrites (Torres Strait Volcanics) intruded by the Badu Granite and minor volcanics within the Cape York-Oriomo Ridge. Gold is associated with the epithermal stages of igneous activity. Recent exploration has defined sub-horizontal zones of disseminated gold mineralisation in the sub-surface, as well as reserves in the outcropping sub-vertical structures mined in the past. Released estimates of 170,00 tonnes proven ore and 550,000 probable ore at 4 grams per tonne gold, have been established.Gold is mostly contained in quartz vein stockworks and hydrothermal breccias within the intensely propylitised medium grained granites which form the local host rocks within the coarse grained Badu Granite. Associated vein minerals are sulphides (primarily of lead, zinc and iron) and calcite. Various intrusions of porphyry, aplite and granodiorite occur through the prospect area.

Jan 1, 1986

By M Colwell

The Coal Mine Roof Rating (CMRR) is a rock (roof) mass classification (RMC) system/index that was originally developed by the United States Bureau of Mines (USBM) for aspects of underground coalmine geotechnical design and was first introduced to Australia as a part of the original Analysis of Longwall Tailgate Serviceability (ALTS) project conducted in 1997/1998. In subsequent years further refinement to its calculation was undertaken, such that the CMRR is now an industry standard for quantifying the structural competence of the primary bolted roadway roof interval and has been routinely/widely used by Australian collieries over the last 25 years with great success for roof support/chain pillar design. There have been many publications discussing the use and calculation of RMC systems and this paper also provides an important update and recommendations in how best to calculate the CMRR. However, it is rare to find an explanation as to why and how a RMC system/index satisfactorily takes account of the mechanics and rock mass behavioural issues associated with ground reinforcement. This paper provides such an explanation and insight with respect to the CMRR so it is: 1) better understood, 2) to allay any concerns, and therefore 3) will continue to be confidently used by and for the collieries’ benefit.

Nov 29, 2022

By P Revell, B Adair, D King, L Keeney

Grade Engineering®, integrated across the mine value chain, has a pivotal role to play in achieving step change reductions in energy and water usage in mine operations. High levels of gangue rejection in the mine can significantly improve mineral head grades and overall productivity. A highly successful example is described at the Minera San Cristóbal (MSC) operation. The nature of the mineralisation in their “intrusive” ore domains in particular has facilitated high rejection rates (75 % of the mass), with significant upgrading of metal to the “accepts” streams (equating to a 2.6 times upgrade in the intrinsic Nett Smelter Return). Results from a series of production trials have confirmed these strong upgrades, resulting in the transformation of mineralised “marginal wastes” to high grade ore feedstocks. If new approaches to more energy and water efficient comminution and separation technologies can also realise gangue rejection at finer sizes in the concentrator, then preconcentration strategies across the value chain also offer the promise of no wet tailings treatment facilities and greatly reduced volumes of waste streams. This “No Tails” strategy is discussed, along with the integrated technologies needed to realise its effect. The work suggests a pathway and insights of a sustainable future for the Minerals Industry, unconstrained by Energy and Water, along with no requirement to produce problematic disposal streams. This strategy has the potential to significantly reposition the social, environmental, financial, and regulatory context of existing and new mining opportunities.

Nov 10, 2020

Legislation introduced for Queensland and New South Wales Coal mines provides different levels of prescription regarding specification of mine seals û generally in relation to capacity to withstand overpressure. In Queensland, the Coal Mining Safety and Health Regulation (2001), Section 341 (d) places a further onus on the statutory ventilation officer to æensure all ventilation control devices at the mine are properly constructed and maintainedÆ and that the ventilation officer æmust ensure a ventilation control device mentioned in the regulation à and installed at the mine meets the design criteria statedÆ for the ætype of deviceÆ. Based on the experience of the author, it appears that risk management and life cycle approach to seals has not been adopted to the same extent as for other aspects of operations. Further, because of the number of disciplines and personnel involved that may influence various factors affecting seal integrity, the opportunity for oversight or unclear allocation of responsibility is considerable. While suppliers can provide explosion or design rated seals, this should only be a starting point for application of the product in a coal mine. Application is often considered by mine planning staff (taking into consideration mine environment parameters such as water, control of gas, spontaneous combustion risk, etc) in conjunction with the colliery ventilation officer, and then construction completed by contractors under supervision of operational staff. After construction, seals often are managed by operational personnel with input from the ventilation officer. Input of the geotechnical engineer into pillar design, roadway opening size, ground support specification and most stable seal location is also required. The need for a customised design approach for each seal site is proposed in order to take into account the many and variable factors that may influence a site so that improved seal performance reliability and predictability can be developed. A program of quantitative as well as qualitative monitoring of performance and triggers for rectification or maintenance action is required, and would provide support to the aforementioned proposal. Many mines rely on visual/audible inspection and periodic bag sampling as the primary means of assessment. Other significant factors such as seal material properties, rib degradation, convergence, floor heave, effects of water on both structural integrity of the seal as well as the air tightness of the seal do not generally receive the same level of attention. Based on the above observations, the author has compiled a reference checklist in regard to the above matters, including aspects of and approaches to mine and pillar design, geotechnical modelling and data collection, civil engineering design, site evaluation and practical options available.

Jan 1, 2005

Two years ago I was sitting in a big lecture theatre at the School of Mines in Kalgoorlie at the annual New LeadersÆ Conference listening to a guy tell us all how much he loved his job, travelling the country ælegallyÆ blowing stuff up à and getting paid to do it. I would have paid to see and do the things he spoke of à now IÆm that guy. From finishing a mining engineering degree at the University of Ballarat, through the job hunt, to firing environmental blasts in Tassie and designing and implementing construction blasts in the middle of the Gold Coast. My name is Rohan Stevens and IÆm a blast-o-holic. While the æjob huntÆ we all embark on toward the end of our degrees is a stressful time, itÆs also very exciting in the current climate. There are a number of things I have learnt through both my hunt for the job that best suited me and working for the worldÆs largest explosives manufacturer. If at least you donÆt benefit from my learnings IÆm certain you will enjoy hearing about (and viewing) some of the work I have had the opportunity to be involved with over the last 18 months with Orica Mining Services.

Jan 1, 2008

Dartbrook mine is a new greenfields thermal coal longwall mine located n the Upper Hunter Valley ten kilometres north of Muswellbrook Figure 1). Construction began in April 1993 with coal extraction starting n October 1994. Longwall production is scheduled to commence in the first quarter of 1996 with production expected to exceed 3.5 million onnes per annum. The permanent workforce will number 150 full-time ,mployees and productivity rates will be 22 000 per employee per annum m a ROM basis. Being a greenfield site Dartbrook has had the opportunity to develop and operate the mine using the best practices and latest technology available to meet high standards of safety, quality and production.

Jan 1, 1995

By D J. D'Astoli, M D. Goodz

In 1993 a detailed review of drill sample yuuluy was rouxluard through twin and triplet drill holes using open hole, crossover suhreverse circulation (RC) and diamond drill methods. Advances in face-sampling RC methods demanded a further review of the validity and reproducibility of drill sample data. A program was undertaken to drill three RC holes using the latest technology (new face- sampling bits, dust suppressers, cyclones and compressors). Volumetric and mass studies were undertaken to review sample recoveries. Modal analyses on indicator minerals were logged to interpret the relative degree of mineralisation. Ambiguities in the results were immediately apparent and the consensus was for follow-up twin diamond holes using HQ3 coring tubes. The most mineralised RC hole was selected for the first twin diamond hole. This RC hole (MS 313) encountered one intersection of >0.47 g/t; in contrast the diamond hole (MS 342) had nine intersections at > I g/t. Results at hand show definitively that face-sampling RC drilling is not acceptable as a method of exploration for gold deposits of the Woods Point type. Furthermore it is demonstrated that RC drilling should not be used for any type of exploration of high-grade gold vein deposits related to highly fractured or porous hostrock, or areas of previous mining activity. Methods are proposed for reviewing of rates of sample recovery, distribution and cross-contamination. Comparisons also show that in limited metreage reconnaissance drill programs, diamond drilling is more similar to percussion in per metre costs, than it is credited with, and always provides more bang for the Buck.

Jan 1, 1997

The Crown Minerals Act provides a new+framework for the management of Crown owned minerals and requires that regard be had for the principles of the Treaty of Waitangi. The Act requires the preparation of Minerals Programmes to achieve the Act's objectives of efficient allocation of rights and the recovery of a fair financial return on its minerals. Efficient allocation requires that a permit is allocated to the party which values it most highly. A fair financial return to the Crown must be considered in the context of the economic rent available from individual mineral projects, with the proviso that a nil return to the Crown as the owner of the resource will not be considered a fair return from the community's perspective.

Jan 1, 1992

Delivery of effective plant shutdowns is primary to the business success of mining and processing plant operations. This paper sets out a methodology that starts with understanding the business objectives of the shutdown and promotes rigorous detailed planning, effective communication, appropriate governance and effective participation of plant operations personnel. The result is delivery of business effective outcomes.

Jan 1, 2004

By L Mikhael Gurieff, D Baas

The Phu Kham Copper-Gold Operation (Phu Kham Operation) is located in the Lao People's Democratic Republic and is owned and operated by the Lao-registered company, Phu Bia Mining Limited (PBM). Australian-headquartered copper and gold producer, PanAust Limited holds a 90 per cent interest in PBM; the Government of Laos owns the remaining 10 per cent. The Phu Kham Operation was commissioned in 2008 with an initial concentrator nameplate throughput of 12 million tonnes per annum (Mt/a). Subsequent improvement projects, including the Phu Kham Upgrade Project (PKU), completed in 2012, and the Phu Kham Increased Recovery Project (IRP), completed in 2013, increased the design throughput to 18 Mt/yr. In 2016, the actual mill throughput exceeded 19 Mt/a, this throughput is budgeted to be maintained until the end of 2020.The concentrator flotation circuit upgrade, completed during the IRP, called for a non-selective bulk sulphide concentrate to be generated from the rougher circuit. This in turn caused the mechanical flotation cells in the cleaner circuit, particularly those in the second cleaner bank, to become volumetrically overload. The overload reduced the cleaner circuit performance to approximately 92 per cent copper recovery at a 23 per cent copper concentrate grade, below the expected 95 per cent recovery. This bottleneck restricted copper units entering the plant to approximately 14.5 tonnes per hour (t/h) due to uncontrolled recirculating load build-up in the mechanical cleaning circuit.Maintaining the operating methodologies would have led to a copper production shortfall beyond 2016, to address this shortfall the Phu Kham Operation looked to optimise the Jameson Cell and mechanical cleaner circuit performance. The work included fundamental application of flotation practice and modelling, mineralogical analysis, bubble size analysis, plant surveys and test work. The results were used to develop and implement an innovative automated control system strategy incorporating flotation theory and operating strategies. The automation has the ability to quickly adapt to disturbances in the circuit and maintain optimised performance with little or no intervention by flotation operators.Upon completion, cleaner recovery increased to 95 per cent at a final concentrate grade of 23 per cent copper, and copper units entering the plant increased to 17.5 t/h.CITATION:Baas, D and Mikhael Gurieff, L, 2018. Developing flotation circuit control and automation for the Phu Kham Copper-Gold Operation concentrator, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 37–58 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

Gold was first discovered on the Shotover by Thomas Arthur in 1862, and soon there were over 3000 miners working on the river. It has often been called the richest river in the world. Most countries probably have one of these, but it was certainly the richest in New Zealand. In the early days some miners collected as much as 200 oz/d from a sluice box, and the early river gravels must have been extremely rich before the gold bearing terrace gravels were sluiced into the river. Otago produced about 10 Moz out of the NZ total of over 30 Moz. Most of this was alluvial and possibly one third or more came from the Shotover. The extremely cold winter and danger of flooding made it a dangerous river to work. During 1863 when heavy rain melted snow in the high country, the river rose 35 ft overnight and drowned many miners camped on the banks. These hazards still exist and dominate the method of working. The early hand miners cleaned out much of the riverbed, and the advent of the hydraulic elevator enabled deeper parts of the river to be worked over. Extensive sluicing of high terraces also took place particularly around Skippers. Several companies have attempted operations on the Shotover. Many of these were distinctly unsuccessful, such as the suction dredge at Maori Point about 1930 and the Skippers Limited fluming in about 1934. At least two attempts were made to divert the river with the Sandhills cut above Skippers and the Oxenbridge Tunnel down near Arthur's Point.

Jan 1, 1983

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

Hydraulic mining shovels can be successively used at open-pit mining operation in severe climatic zone with air temperature interval from -700C to +450C typical for some northern region of the world particularly of Russia, Canada and Sweden, if they would be equipped by special preheating facilities for their diesel engine, water, hydraulic oil and lubrication systems. All shovels manufactured by the Komatsu Mining Germany GmbH for operation at ambient air temperatures down to -50¦C have cast and forged structural design elements, bolted connections made of special steel grades, electric cables with special insulation, flexible high-pressure hoses manufactured by ICE-Champion with connectors made of special steel grades.Generally at the temperatures below -25¦C the ordinary machine has to be stopped, the attachment should be placed in the parking position, the generator should be switched on, or the external electrical power supply connected, for the preheating equipment. For rapid start-up in winter after a long shutdown of a hydraulic shovel, there is a procedure for preheating of the main systems. It is applied for the following systems: engine cooling system, engine oil, hydraulic oil, pumps and drive motors of the propel gears, electric cabinets, machinery house, especially near the ventilation inlets and outlets.Start-up of the main drive engine is permitted at a hydraulic oil temperature of -20¦C, when it has a viscosity of 1000 cSt. In this case the rotation speed of the diesel engine crankshaft is lower by two times than the nominal value and this is the most favourable condition of start-up of the engine and hydraulic pumps and motors, which work with half of their rated rotation speed until the hydraulic oil reaches a viscosity from 100 to 10 cSt. After that the hydraulic system and the entire shovel begin to operate under normal conditions.

Dec 6, 2010

This paper addresses, in particular, the influence of winding depth on the selection of head ropes for Koepe winders. Because this is just one aspect of winder design that affects the operational safety of the winding system, the paper starts by considering all the issues governing the life and safety of the winding ropes. Regulations from a variety of countries are reviewed and comparisons of the legislated rope factors of safety and their variation with winding depth are made. This is followed by a discussion of the typical observed mode of in-service deterioration of Koepe head ropes. This mode of deterioration is due to fatigue and is influenced by the load range occurring in the ropes. Parameters contributing to load range are discussed and the influence of winding depth is highlighted. Lessons learned from early experience with very deep Koepe winders in South Africa are recalled. Predictions of load range as a function of depth are made, from which general rope life predictions are made for ropes selected by conventional national factor of safety requirements. This is illustrated in graphs comparing rope life as a function of depth. Typically a reducing life with depth is predicted. A rope selection strategy is advocated, which is based on achieving a constant rope life irrespective of the depth of wind. A new factor of safety (or rope design factor) equation is prepared that has the trend of increasing with depth. This proposed equation is compared with other published proposals that promote an increasing rope factor of safety with depth. It is shown that smoother winder drive controls enhance winding rope life and this improvement is quantified. The paper concludes by pointing out the consistency in predicted and observed life of winding ropes selected in accordance with legislated factor of safety approaches. It recommends the adoption of a new rope design factor equation for rope selection, to be used in conjunction with appropriate codes of practice for winding rope condition assessment and for the design, installation, operation, maintenance and testing of Koepe winders. The new rope design factor equation approaches a limiting economic depth of wind at shallower depths than the existing Koepe factor of safety approaches. However these older approaches æbuild-inÆ a reducing rope life with depth. The new rope design factor is therefore a more consistent way to select Koepe ropes and to evaluate economic trade-offs between Koepe and conventional double-drum or Blair winding systems.

Jan 1, 2005

By K Peters, C McKenzie

New Zealand has an established history of gold production beginning with the gold rushes of the 19th century in the Coromandel, Nelson/Marlborough, West Coast and Otago regions. Despite this, the number of significant modern hard rock gold operations has been limited in recent years due to a lack of sustained exploration capital and not limited geological prospectivity.The New Zealand Government is actively encouraging explorers to invest in New Zealand through a series of targeted promotional visits, more importantly through the acquisition of precompetitive regional geophysical data. Data collection has been completed over the prospective Northland epithermal district and a large portion of the South IslandÆs west coast that is prospective for both orogenic gold and intrusive related gold.Analysis of new data has been an important component in aiding the generation of exploration targets from prospectivity modelling. Determining the prospectivity of an area involves reviewing all the available data and analysing it with respect to the most up-to-date mineral system model for the mineralisation style of interest. Using the weights of evidence modelling approach, the most prospective areas for epithermal gold-silver, orogenic gold and intrusion-related gold have been identified. The key exploration parameters relevant to each mineral system are first represented spatially and then statistically combined into a single prospectivity map. New potentially economic deposits could be found by focusing exploration on targets identified from these models. The prospectivity modelling approach can greatly reduce the risk involved in mineral exploration.CITATION:Peters, K and McKenzie, C, 2013. New Zealand gold potential - using mineral prospectivity modelling to evaluate gold-bearing mineral systems in an underexplored country, in Proceedings World Gold 2013 , pp 479-486 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

The ERMS Process was developed during four years of testwork by Austpac Gold NL to overcome the severe metallurgical problems of the ilmenite atWestport, in the South Island. These deposits have been known for about one hundred years. They were originally mined for gold, and only later attracted attention as a possible source of titanium minerals.   The resource is of world scale and may exceed 20 million tonnes of contained ilmenite. Similar deposits occur at Barrytown further south and together these areas would constitute an important opportunity for export-oriented mineral development, if a viable beneficiation technology were available. Further processing is essential, as the composition of the ilmenite is well below market specifications.

Jan 1, 1993

By J R. Leeming

Mining law has developed in Great Britain (GB) over centuries, mainly in response to lessons learned after disasters and other major incidents. This has led to a culture of preventing repeat accidents, rather than predicting and controlling unsafe acts or conditions.This paper explains how, initially in response to a government drive to reduce the burden on industry, the opportunity was taken to review and reform all 48 sets of GB mining-specific law into a single document. The philosophy adopted, the procedure followed and the significant changes that resulted are explained.CITATION:Leeming, J R, 2017. The complete renewal of Great Britain’s mining laws for the 21st century, in Proceedings Australian Mine Vent Conference 2017, pp 3–8 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By P V. A van der Westhuyzen

Namakwa Sands is a heavy minerals mining and beneficiation business in the Exxaro Sands Division, and operates along the West Coast of South Africa (see Figure 1). The business encompasses mining, mineral concentration, separation, and smelting operations. Inflated commodity prices and increasing operating costs demands greater attention to the management of process performance and the company wide coordination of resources. Consequently, the task of deploying operational/technical skills and budgets into the most appropriate parts of the business assumes great importance in order to increase productivity from its capital assets. The mineral sands industry is under the same sort of economic scrutiny that all other industries find themselves, and as such, Exxaro – Namakwa Sands has taken the strategic initiative to improve overall resource utilisation within the processing steps and to measure the costs associated with obtaining this value.This paper provides details of the successful implementation of a Kelsey Centrifugal Jig (KCJ) at Namakwa Sands to recover primary and secondary zircon products from the wet gravity (quartz) rejects generated and stockpiled at the Mineral Separation plant (MSP).

Oct 5, 2011

By R Mann, R Prasad, S Vink, V Nanjappa

The level of salinity that various aquatic organisms can tolerate without incurring any adverse effects is dependent on several environmental and evolutionary factors. These factors include the relative concentrations of different types of dissolved salts in the water that makes up their habitat, the regimes to which organisms are exposed to waters of differing salinity levels (including naturally derived variations), the degree to which an organismÆs life history stages have adapted to salinity, an organismÆs ability or behaviour to avoid adverse levels of salinity and an organismÆs capacity for osmoregulation.Release of saline water into rivers of the Fitzroy catchment has created concern about the impact on aquatic organisms. Not only is salinity itself a stressor on organisms but different ionic compositions will moderate the effects. Ecotoxicology experiments were conducted using artificial saline water based on mine water chemistry using sensitive macroinvertebrates collected from the catchment, as well as a range of laboratory organisms in accordance with the ANZECC and ARMCANZ (2000) guidelines. The 95 per cent ecosystem protection value calculated from species sensitivity distribution derived from the commercial tests was estimated to be ~2.0 mS/cm. For the protection of 99 per cent of the species the salinity has to be reduced by more than 50 per cent to 0.91 mS/cm. The electrical conductivity (EC) values, derived by commercial testing and species sensitivity distribution in this study suggests that salinity contaminant trigger values previously developed using a referential approach for protection of aquatic ecosystems from saline mine water releases in the Fitzroy may be conservative.CITATION:Vink, S, Mann, R, Nanjappa, V and Prasad, R, 2013. Determining the impacts of salinity on freshwater organisms, in Proceedings Water in Mining 2013 , pp 149-154 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013