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By Brathwaite RL

The gold-scheelite-quartz lodes of the Wakamarina valley were the most productive of the mesothermal gold-bear in the Marlborough Schist. Most of the production came from the Empire City and Golden Bar mines which worked tug, Golden Bar lode. Only 134 m of its 1800 m strike length are accessible, in the No. 2 level of the Golden Bar Mine. A fau I has downthrown the Golden Bar Mine section by 2 47 m and displaced it left-laterally by 18 m. The lode is a typical ribbon-banded mesothermal vein, averaging c. 1.75 m wide, and enclosing narrow horses of schist country rock. It i composed of bands of milky "buck" quartz with thin laminae of schist. Scheelite occurs in short strings of grains withi quartz on the footwall side of the lode and also in small quartz-carbonate veinlets in the foot wall and hanging wall schist The lode quartz contains only localised traces of pyrite and arsenopyrite. They are more abundant in the wall-rock schist.

Jan 1, 1995

Backfil ling of excavated Sub Level Open Stopes has been underway since March 1989 and as at December 1992 some 1 100 000 cubic metres of Cemented Aggregate Fill have been placed. During these three years significant developments in fill quantities, types and cost have taken place.Operational improvements have reduced the quantity of Cement Aggregate Fill by 40 per cent. These results have been achieved by:ò rescheduling stopes,ò designing smaller primary stope, and ò use of uncemented rockfill.Unit cost for Cement Aggregate Fill have fallen in the order of 50 per cent through:improving fill hole reli ability,simplified barricade construction procedures, reducing the cement content,ò substituting dune sand for deslimed mill tailings, ò improved maintenance at the Backfill plant, and ò renegotiated site freight agreement.This paper will review the historical developments of backfill use at Olympic Dam.

Jan 1, 1993

By R Winterberg

Concrete is a well established and reliable construction material for the permanent lining of tunnels, but shows some weak performance characteristics, which can be overcome by the addition of specialised fibre reinforcement. This paper addresses the particular performance design requirements of segmental linings, discussing the improvements of fi bres on concrete properties. Focus is made on the beneficial effects of fibre reinforcement on the cracking behaviour and the toughness performance, providing a safe and durable tunnel lining.Not only the mechanical performance of fibre reinforced concrete (FRC) for segmental linings, but also the durability of the linings has gained growing attention among the designers and consultants. Especially tunnel linings with exposure to media with corrosion potential, such as wastewater sewer tunnels or desalination plant outfall tunnels, have high requirements on their durability. The design of these structures must provide a comprehensive study of durability aspects. Fibre reinforcement can substantially improve the durability of concrete.Research has been carried out on the cracking behaviour of concrete. The beneficial effects of steel fibres on the cracking behaviour reduce the permeability by reducing the flow paths within the concrete. Crack bridging steel fibres create necking effects in bending cracks, leading to earlier closure of the cracks. Further, steel fibres create particular crack formations, which lead to a substantial reduction of the fl ow rates through separation cracks. The results also show that considerable cost savings can be achieved using FRC, as the thickness of the linings can be reduced.The durability design issues will be addressed and underlined by a case history on the Hobson Bay sewer tunnel in Auckland, New Zealand.

Mar 8, 2011

By Z Li, J Pan, D Zhu, W Zhou

In order to enhance the roasting behaviours and metallurgical properties of hematite pellets, which have the problems of high roasting temperature and low compressive strength, a process of producing Brazilian hematite pellets by adding high sulfur magnetite was developed in this paper, and process parameters have been optimised. It is shown that the roasting temperature decreases from 1320¦C to 1200¦C by adding 30 per cent of high sulfur magnetite. New Fe2O3 crystal oxidised from Fe3O4 is more active, which is beneficial to induration of pellet. When the ratio of magnetite increased to 50 per cent, only about 90¦C of the roasting temperature was decreased. Higher ratio of high sulfur magnetite causes more porosity of pellets because of oxidative desulfurisation, which is harmful to the strength of roasted pellets. The reduction disintegration index (RDI), presently RDI+3.15 of product pellets is aggrandised from 87.79 per cent to 99.54 per cent and 97.55 per cent, and the reduction swelling index (RSI) is lowered from 36.25 per cent to 12.50 per cent and 6.25 per cent respectively, by adding 30 per cent and 50 per cent of high sulfur magnetite. The compressive strength of roasted pellets is elevated obviously by adding high sulfur magnetite, which resists the inner stress of pellets during reduction process, so as to enhance the RDI and reduce the RSI of product pellets. In addition, the inner porosity may be filled by the swelling during the reduction process, which can also lower the RSI. The process provides a low power consumption of making hematite pellets that high sulfur magnetite can decrease roasting temperature significantly and improve the metallurgical properties of hematite pellets dramatically.CITATION:Zhu, D, Zhou, W, Pan, J and Li, Z, 2013. Study on improving roasting behaviours and metallurgical properties of Brazilian hematite pellets by adding magnetite with high sulfur content, in Proceedings Iron Ore 2013 , pp 525-530 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

Diamond drilling is a relatively new commodity in terms of drilling. The first known diamond drilling activities were carried out in the Swiss Alps around 1863 when the Swiss engineer M Leschot designed and made a tube with a diamond set face which was used in probing ahead drilling for the Mont Cenis tunnel (Figure 1). Craelius AB which today is a part of the Atlas Copco Group was formed in 1886. The name Craelius is a family name and the founder of the company was Per Anton Craelius (Figure 2). He went to the United States to study this new technology using diamonds to extract core samples and when he returned to Sweden designed his first diamond drilling machine. It was a man-powered drill needing a crew of six men, two to crank the unit, one to feed, two to power the flush pump and a foreman (Figure 3). As time passed through research and development, the original design was improved and manpower was substituted for steam engines and later combustion engines or electric motors (Figure 4). During the 1930s the drills radically changed designs and took the form of the short stroke drills which to a certain extent are still in use today. The original design of these drills have been refined during the years, hydraulic chucks, gear boxes and other improvements have been added.

Jan 1, 1995

By Morrison R. S, Doennilan N

Recent mapping (1989-1992) by the Northern Territory Geological Survey in the Tennant Creek 1:250 000 map sheet area has resulted in substantial revision of the lithostratigraphy of the Tennant Creek Block (Donnellan, Hussey, and Morrison, in press). Briefly, the former Warramunga Group (Dunnet and Harding, 1967; Dodson and Gardener, 1978) is divided into the Warramunga Formation, and an overlying less deformed volcano-sedimentary succession, the Flynn Subgroup. The latter is conformably overlain by the Tomkinson Creek Subgroup of the Tomkinson Creek province in the north of the Tennant Creek Inlier. These two Subgroups constitute the Churchills Head Group which is essentially equivalent to the Hatches Creek Group of the Davenport province to the south of the Inlier.

Jan 1, 1994

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 M R. Drumond

The present work presents a new theoretical interpretation of the flotation process, which can also be applied to other mineral processing physical unit operations. This interpretation is part of the æModelo OperacionalÆ (Operational Model) that was developed as an attempt to establish a new theoretical basis for mineral processing unit operations. In the case of flotation, a book was edited by one of the authors in Brazil (Mass Concentration by Froth Flotation, in Portuguese and Spanish).The model establishes a link between a natural phenomenon (migration of particles from the pulp to the froth) and a real industrial phenomenon (mass concentration by operational interference). In this model, flotation is viewed as a phenomenon of macromolecular mass transport (of particles) between froth and slurry phases. Mechanisms for mass transport and particle flow between phases as a function of the hydrophobic potential in each phase are discussed. By establishing the so-called equilibrium distribution curve between phases it is possible to calculate macroscopic balances that are related to metallurgical results, which in turn are a function of the operational line that is required by the process itself. The number of cleaning stages and their efficiencies can also be determined by simple laboratory-scale experiments.

Jan 1, 2005

By G T. Jemwa, F Rousseau, F J. Wolfaardt, J A. M Rademan, P W. Smit

Mining companies are increasingly faced with the challenge of reducing operating costs while maximising throughput and profitability. At the same time, the grade and quality of treated ores are becoming poorer and more variable, resulting in suboptimal process performance.It is now widely accepted that strategies to drive operational goals must revolve around improving plant availability, reliability and process efficiency. In particular, progress in plant automation and control systems has seen a trend towards unified frameworks for control and optimisation of mineral processing plants. These frameworks seek to seamlessly integrate different roles and tasks involved in process operations - IT, automation, plant maintenance and operations. An integrated solution framework for reducing process variability, increasing process efficiencies and maximising plant availability and reliability is discussed within the context of a typical milling circuit. The framework exploits a real-time analysis ægapÆ evident in production operations that prevents timeous identification of equipment and process failures. This is achieved by leveraging predictive analytics for equipment health monitoring, control loop monitoring and advanced regulatory control solutions towards enhanced process performance, improved asset management and regulatory compliance. The framework provides for early and actionable warnings on equipment and process degradation using real-time operational data.Resolving these problems can potentially avoid unplanned downtimes, process instabilities and other operational surprises, thus ensuring optimal plant throughput and optimal process behaviour for improved recoveries. Integrating control systems and plant automation with advanced analytics to analyse and optimise processes enables operations to achieve reductions in the variability of key process parameters. In addition, early detection of equipment malfunction or suboptimal process conditions leads to improved equipment availability and reliability. Ultimately, these operational gains reflect in profitability because of plant throughput and recovery gains. These benefits are demonstrated using data from a South African gold mining operation, where such an integrated asset and process health monitoring framework for process optimisation has been implemented.CITATION:Jemwa, G T, Wolfaardt, F J, Smit, P W, Rademan, J A M and Rousseau, F, 2013. Towards an integrated framework for asset and process health monitoring and optimisation on a milling circuit, in Proceedings World Gold 2013, pp 137-148 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By Z Fu, E Topal, O Erten

"Mine waste rock management involving waste rock movement and placement, is a critical aspect in the planning of open pit mining operations, as the waste rock haulage cost can be the largest portion of the mine operating cost. The concept of sustainable development in the mining industry also encourages environmentally friendly waste dumps that have zero hazards to people and the surrounding environment. Therefore, a detailed waste management schedule must satisfy economic and environmental considerations. However, the available tools in the market cannot provide optimal waste dumping schedules to meet all these constraints. This paper introduces a user-friendly and automatic tool to optimise the waste dumping schedule, which minimises the haulage cost, and covers the encapsulation of reactive materials to minimise acid mine drainage problems. This tool has been developed by using a new mixed integer programming (MIP) mathematical model that considers both single-lift and multilift dumping scenarios. The application of the proposed tool on a data set collected from a gold mine shows that the multilift dumping scenario has provided a more flexible and economical waste dumping schedule than the single-lift scenario, and both scenarios satisfy environmental requirements.Citation:Fu, Z, Topal, E and Erten, O, 2016. A Modified Software Tool for Mine Waste Rock Dump Planning, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 229–242 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

During the first five years of operation, the Lihir gold mine has steadily increased plant throughput rate to over 4 Mtpa, well above the original design capacity of 2.8 Mtpa. Understanding how future variations in ore type impact on plant performance has been an integral part of LihirÆs development program. This paper discusses the key drivers for significant improvements to the plant, including a second oxygen plant, a pilot flotation plant, an autoclave heat recovery circuit, a pebble crushing circuit and additional autoclave feed pumping capacity. The result is a process plant with the flexibility to accommodate variations in ore type without significant loss of throughput.

Jan 1, 2003

The modern resource extraction enterprise is a complex capital intensive business operating in a world of constantly evolving social, environmental and economic scrutiny. Investors, government, media and special interest groups expect to see business environmental and social performance respond and deliver increasing corporate responsibility and sustainability.   Thorough interrogation of business performance using a multi-disciplinary due diligence approach presents a more sophisticated review and benefits beyond the traditional compliance/conformance 'audit' style assessment.   Using a due diligence approach allows assessment through a comprehensive lens which examines potential short- and long-term risks including sometimes less tangible environmental and social liabilities, and informs management, investors and regulators of broader business performance. This approach provides information in a form that business can measure performance in a repeatable and enterprise wide sense.   This paper provides an outline of the due diligence process applied in this way, drawing from lessons learnt and industry based experiences in the due diligence process and the benefits and tools that can  be applied in an environmental and social due diligence business performance assessment

Jun 1, 2010

The concept of æsustainabilityÆ can largely be defined as development that will not compromise the ælivabilityÆ of the planet for future generations. It has multiple dimensions, such as the triple bottom line û environmental, economic and social. And it also includes temporal (now and the future) and spatial (local and global) aspects that have to be taken into consideration to achieve true sustainability.Energy sustainability might be defined as û having the light turn on when you push the switch. It has, of course many more dimensions than this simplistic definition. Coal in Australia has an important role in keeping our lights on, but has its problems that need to be tackled head on to maintain a role in sustainable development.An overriding issue in terms of sustainability for coal is its major contribution to our greenhouse gas emissions. Whilst we have one of the most effective energy sectors in the developed world, based on well-managed, abundant fossil fuels, our greenhouse gas emissions are one of the highest per GDP in the developed world. We have to reduce our ægreenhouse gas signatureÆ.This paper explores the issues of coal utilisation greenhouse gas emissions as an indicator of the fuelÆs sustainability and the potential lower emissions pathways we will have to follow in a future carbon-constrained world.The technology changes will have significant implications for the minerals industry and it is argued that forward-looking coal/greenhouse emissions strategies need to be developed in alliance with the coal (and energy) sector for the minerals industry to maintain its global competitiveness.

Jan 1, 2004

By M W. Chen, I Canbulat, S Saydam, C G. Zhang

The height of fracturing (HoF) measures the propagation distance of continuous fracturing from the mining horizon and is also termed the height of cracking (Hebblewhite, 2020; Khanal et al, 2019) or hydrologically the height of groundwater drainage (Tammetta, 2013). In longwall practice, HoF is an important predictive indicator for assessing the dewatering effect of panel extraction on the shallow aquifer and surface flows. The HoF determination is basically dependent on field measurement works, typically using surface extensometer, borehole televiewer imaging, piezometer monitoring, packer testing, borehole breakout logging, and isotopic tracer monitoring (Brown and Walsh, 2022; Corbett, 2022; Hebblewhite, 2020; Holla and Armstrong, 1986; Mills and O’Grady, 1998; Walsh et al, 2022a, 2022b). These methods or tools have been widely applied to observe rock fracturing and groundwater responses to longwalls at Australian coalmines, for example, Dendrobium Mine (Brown and Walsh, 2022; Walsh et al, 2022b), Appin Mine (Walsh et al, 2022a), and Springvale Mine (Corbett, 2022). In Chinese mines, borehole televiewer imaging and packer testing are more frequently used due to convenient instrumentation, quick testing, and not requiring long-term maintenance of the instrumentation boreholes. The HoF determination also involves further raw data interpretations, for which specialist software for data extraction and quantitative criteria for bounding the fracture transition and termination are necessary. By combining the measured fracture distribution and longwall parameters regarding panel geometry and geological settings, several HoF models have been developed for conceptualising the understanding of strata depressurisation and providing mine engineers fast calculation tools for HoF prediction. The Mackie model considered the height of fracturing as the upper bound of fractured zone and revealed that within the fractured zone there are highly connected fractures and accordingly porosity enhancement and groundwater depressurisation, where the fracture network can be less transmissive from the mining horizon up (Hebblewhite, 2020). The fractured zone shares similar fracturing regime but different heights in varying models: HoF is 30 to 58 times of the mining height (t) based on Australian, Soviet and UK experience (Kendorski, 1993, 2006), and 21 to 33 t according to the field measurements in NSW Central Coast, Australia (Galvin, 2016). Some Australian longwall mines adopt Ditton model (Ditton and Merrick, 2014) (Equations 1.1 and 1.2 in Table 1) sourcing from NSW coalfield experience for HoF prediction, while Liu model (Liu, 1981) (Equations 2.1 to 2.4 in Table 1) developed from 27 coalmines in China is frequently used by Chinese coalmines.

Nov 29, 2022

By J J. Boshoff

This iron ore mine site, located in the Pilbara region of Western Australia, commenced operations in 1998, with ore derived by mining of open-cut pits in Channel Iron Deposits (CIDs). A portion of the ore extracted at the mine is processed at wet processing plants that produce both ore saleable product and waste fines (i.e. tailings) slurry. The waste fines produced at the wet plants are presently stored within Waste Fines Cells (WFCs).Waste fines cells A (WFCA) and B (WFCB) are located within an Autonomous Haul System (AHS) area and consist of embankments that span the width of the pit in east-west alignments. Technical studies and design analyses were carried out to support embankment raises and ongoing development of the WFCs. During operation and development of the WFCs, a multitude of simultaneous activities took place to the immediate north and south of WFCA respectively. These activities included the construction of the embankment raises using the AHS fleet, mining of the CID to not only mine the ore but to also create future deposition space for WFCB, blasting next to the WFC embankments as part of the mining activities, seepage collection and dewatering of the pit in the vicinity of the WFC.This paper discusses the material characteristics, design approach, construction staging and equipment requirements, blasting near embankments, water management, facility consequence category and closure concept.CITATION:Boshoff, J J, 2018. A waste fines cell with a multitude of concurrent activities, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 39–49 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

Optimal drill and blast design is a process often neglected by many underground hard rock mines. This is even more important to the new mine where ring designs need to be implemented and refined in a short period of time. In today's environment where more and more mining is being carried out by contract specialists it is the co-operation between a principal and contractor, who are working towards a common goal, that achieves the highest quality end result. The development of drill and blast designs that cause minimal damage to the mine infrastructure is particularly important to Northparke's E26 Block Cave Mine, as it consists of a single extraction level which must survive intact for the life of the mine. The advanced undercut mining method implemented at Northparkes is fired in a sequence which protects the mine development from potentially damaging abutment stress. This paper details how blast designs will be optimised and sequenced to satisfy the conflicting objectives of maximum rock breakage inside the drill pattern and minimum rock damage outside the pattern.

Jan 1, 1995

By Yeliseyev AK, Shestakov AM

Comminution is the most power-intensive process in the technology for ferrous quartzite concentration. That is why improving comminution efficiency leads to the most appreciable economic effect on the concentration process. The trend towards reducing the lump size of crushed ore before charging the mill is considered to be of major importance in improving comminution efficiency. A considerable number of investigations have been performed in this direction. At the same time, a strong interest is also maintained in the increase of comminution efficiency due to optimisation of process taking place in the mill. Recently, investigations of the power intensity of the breaking process inside the mill have been carried out at the Krivoy Rog Mining Institute. It was ascertained that the routine conditions of comminution at a low mill ball charge ratio resulted in an unnecessarily high power consumption due to the force of impact of falling and milling bodies far exceeding the power required for comminution. For example, the power value for falling balls of 60 - 125 mm in diameter reaches 0.3 kNm, and the force and stress due to ball contact with the lining reaches 60 kN and 250 MPa respectively. These values exceed the force required for comminution by a factor of ten. Analysis of the mechanism of ore particle size reduction during comminution in the ball mill indicates that the size reduction is due to impact load, attrition load, and static load. The efficiency of size reduction is very low. During comminution in the ball mill, impact loads prevail and amount to 85 - 90 per cent of the total load. In this situation, not more than 10 - 15 per cent of destruction is due to attrition.

Jan 1, 1993

By Miyatani J. Asaki Z, Kondo Y

The oxidation of sphalerite particles of 60 to 100 mesh size was studied in a fluidized bed of low 02 concentration at 900¦C. Par- tial pressure of 02 in the fluidizing 02-N2 gas mixture was chosen between 0.0009 and 0.02 atm. In the region of p02 between 0.008 and 0.02 atm, the oxidation rate was lowered with the decrease of p02, and the unreacted-core model was applied. At lower pbelow 0.008 atm, the reaction rate was enhanced as compared with the calcu- lated values from the unreacted-core model. From microscopic examination, it was found that ZnS was evaporated at the particle surface and the dissociated Zn vapor was oxidized in the gas phase. Initial reaction rate and the distance between the surface of inner sphaler- ite core and the oxide shell were studied based on the model of enhanced oxidation.

Jan 1, 1980

The brown coal resources of the Latrobe Valley, which include over thirty thousand million tons of coal suitable for open cutting, provide the main source of fuel for the power generation for the State of Victoria. They also provide the basis for the development of a supply of cheap hard fuel for industrial and domestic use, and for the development of the Lurgi process for manufacture of town gas for most of the State. The production of hard char for metallurgical processes and liquid hydro carbons will each, no doubt, play its part in the industrial growth that will be based on these resources.The State Electricity Commission of Victoria, which has been allocated the task of developing these deposits since the early 1920's, is faced with problems of economic selection of deposits for development, and excavation and transport of huge tonnages of coal and overburden-in this year, 19'59, about 12,000',000 tons of brown coal will be won, and over 7,000,000' cu. yd. of overburden will be removed in the four open cuts operated by the Commission; by 1967, eight years from now, the demand will have doubled.This paper deals with the nature and importance of various factors effecting the planning of the development of these resources. It is in essence an introduction to the papers by C. S. Gloe, H. C. G. Rodgers and J. M. Alexander, also being -presented at the Institute conference in Victoria in August, 1959.INTRODUCTIONIt is the intention in this paper to define the factors that come under consideration in the planning and development of the brown coal fields in the Latrobe Valley, whose exploitation by the State Electricity Commission of Victoria was initiated almost 40 years ago. It is proposed to enumerate, and in sorile cases evaluate, the physical and economic criteria that play their part in determining planning for the future.

Jan 1, 1960

Sampling protocols and metallurgical flow sheets should be designed to suit the style of mineralisation in question. In support, the a priori need for evaluation programs is the characterisation of the mineralisation type(s) and domain definition. The proportion and size of gold particles has a direct impact on the effectiveness of sampling protocols and metallurgical processes employed. Within the coarse- to-fi ne gold spectrum, the samplability of a deposit ranges from relatively simple for fine-grained disseminated particles, through to difficult for coarse gold mineralisation. Conversely, metallurgical processing may be relatively simple for coarse gold ore and more difficult for very fi ne gold ores. Most deposits contain a proportion of both particle size types. The nature of mineralisation, mineralogy and associated gold particle sizing can only be determined by preliminary sampling to facilitate testing. Mineralogical studies, focussing on ore mineralogy and gold particle deportment, size and distribution are required as part of wider paragenetic and geometallurgical investigations. This paper discusses key issues and presents a methodology for the determination of gold particle size in coarse gravity-gold ores to support sampling optimisation and which also contributes to metallurgical characterisation.

Aug 1, 2010