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By F Radke, P A. Tilyard

Determination of the mineralogical location (deportment) of minor and trace elements (including credit and penalty elements) in base metal concentrates can indicate whether further processing is likely to (a) reduce the levels of the penalty elements, and/or (b) direct selected elements into other plant products, thereby increasing current concentrate grade or increasing payment for credit elements. To determine the deportment of elements requires knowledge of the proportions of the minerals present and their individual element contents. In addition, knowledge of the liberation and locking is important, as this can affect any possible further processing. Mineral proportions can be determined by a variety of methods including chemical analysis, point-counting, area-counting, QEM*SEM, image analysis and mineral separation. In the case of a Broken Hill zinc concentrate, several of these methods were used and gave consistent results.

Jan 1, 1998

By K L. Brown

Sampling and analyses of deep waters from Wairakei and Rotokawa geothermal systems indicate a wide range of precious metal concentrations (<0.1 to 23 ppb Au; 6 to 2400 ppb Ag), suggesting that eastern ôandesiticö TVZ geothermal systems (eg Rotokawa) have higher aqueous gold and silver than western ôbasalticö geothermal systems (eg Wairakei); this interpretation is consistent with known occurrences of high grade precipitates in wells from eastern systems. The fact that the deep waters are undersaturated in gold further suggests that the aqueous gold concentrations of deep waters are limited by metal availability. The flux of gold for the two systems ranges from ~1 to 50 kg Au/yr, and the flux of silver ranges from 65 to 6900 kg Ag/yr. At Rotokawa, it only takes ~600 years to flux one million oz of Au and >100 million oz of Ag. The supply of hydrothermal gold and silver is obviously important during genesis of an epithermal deposit, but ore formation also depends on the existence of a suitable ôtrapö that efficiently extracts metal from solution in a small volume of rock. Such traps seem to have been poorly developed until geothermal drilling in the TVZ.

Jan 1, 2006

By R Cunningham, P Duniam

Late in 2005 it became apparent that cave propagation at the Northparkes Mine was not progressing as planned. By mid-2006 sufficient Reserves were identified to warrant an extensive drill and blast program to assist in cave propagation. This program began late in 2006 and concluded early 2007. A significant challenge faced was the drilling and blasting of holes between 75 - 240 m in length in the South Wedge in Lift 2 at Northparkes Mines E26 orebody. The project set new benchmarks in production drilling and charging in underground metalliferous mining. This paper discusses the drill and blast designs, the challenges and the operational issues encountered with this project. Also highlighted are ways in which these were overcome.

Jan 1, 2007

In recent years there have been many changes in mine ownership due to the on-going rationalisation towards larger mining companies. Larger companies inevitably find it hard to manage small mining operations and in many cases smaller mines do not fit corporate resource, production and profit criteria. Smaller companies are more suited to managing these medium or small scale mines and are tendering for the purchase or lease of mines that larger companies wish to dispose of. In addition to these factors there has also been a trend (especially in Western Australia) for mines to continue operating at ever increasing depths. This in turn has led to more mines operating in high stress environments and experiencing damaging seismicity. Assessing the viability of seismically active mines from a takeover or purchase point of view should involve analysing the risk profile of every aspect on mining that could be affected by adverse seismicity. This includes assessing current and alternative mining methods, mine designs, support systems, extraction sequencing, monitoring and blasting. This paper includes discussion on items that need to be assessed when considering the purchase of seismically active mines, with experience gained from some recent studies in Western Australia. In these cases it was apparent that quantification of previous seismic history on itÆs own was a totally inadequate method of assessing minewide seismic risk potential. A more holistic approach is required, taking into account all aspects of relevant data, all the minewide effects of seismic activity and all possible means of mitigating those effects.

Jan 1, 2002

By J Morton

The Resource Management Act 1991 represented an innovative and unique piece of planning and environmental legislation when it was introduced. Since the Act was passed into law in 1991 it has been subject to nine amendments, many of which were of the ætinkerÆ variety. These amendments recognise that the Act has not been as successful in providing the æone-stop shopÆ for resource users that the Act was hoped to be. The latest and most significant attempt at changing the Act was the Resource Management Amendment Act 2003. The amendments made by the Amendment Act have proved to be largely unsuccessful in achieving any significant changes to the way resources are managed in New Zealand, and have failed to address many of the concerns which drove the original Resource Management Amendment Bill in 1999. The recent decision to discontinue further investment in Project Aqua has once again placed the Act in the spotlight as a significant hand-brake on major projects. This particular event has led to yet another review to be undertaken this year. The review will focus on five key areas:   1.   achieving the right balance of national and local interests; 2.   improving the design and process for local policy formulation; 3.   improving the consent decision making process; 4.   allocation of natural resources (water, air and geothermal); and 5.   supporting measures for building capacity and promoting best practice and implementation at the local authority level.  It is important for the business community and the mining industry in particular to seize the opportunity that this review provides to make sure that any amendments undertaken as a result of the review achieve the aims listed above. The review needs to be considered in light of the current regime for the management of natural resources in New Zealand. In addition to the Resource Management Act 1991, the Crown Minerals Act 1991 and the Building Act 1991, which form the core resource statutes in New Zealand, there have been other developments affecting the regime. Special legislation over and above the Resource Management Act 1991 has been enacted to protect the Hauraki Gulf and special legislation is currently being considered to protect the Waitakere Ranges in Auckland. In the Hauraki District mining is prohibited in some areas and a plan change mechanism is specified as the appropriate tool to use in the event a mineral resource is to be developed in those areas. The current review is a further opportunity to remedy the inadequacies of the Act.

Jan 1, 2004

By D Mather

Fibre reinforced shotcrete has long been accepted as temporary ground support in both mining and civil tunnel linings. Greater knowledge and understanding of shotcrete as an engineering material and advances in its quality have enabled designers to eliminate the requirement of a second pass lining. The initial shotcrete can be used as the permanent tunnel lining or be incorporated into the final lining design, rather than ignored and considered as sacrificial.For the initial shotcrete lining to become a suitable permanent tunnel lining it must be able to establish and maintain stability over time when subjected to all possible loads. To ensure this, best engineering practices are required during the design phase of the project to analyse; ground conditions including rock mass properties, ground and ground water quality, rock mass loadings, excavation sequencing, and construction methodologies.The increased durability of steel fibre reinforced shotcrete over traditional tunnel support, in the right ground conditions, makes it possible to achieve a serviceability design life of greater than 100 years (as required in most infrastructure projects). By specifying a good quality shotcrete mix and ensuring adequate quality control for batching, fibre dosing, preproduction testing, excavation sequencing, and application control, it is possible to eliminate the requirement of a secondary lining. The properties of a suitable permanent lining must be well established using suffi cient preproduction testing in combination with post application monitoring.A major benefit of steel fibre reinforced shotcrete in ground support applications is the removal of any requirement for workers to work under unsupported ground. Its use can also significantly reduce, if not eliminate, the manual handling associated with placing traditional reinforcement such as lattice girders and mesh. Both of these benefi ts are significant with the ever increasing focus on health and safety.This paper highlights factors that must be considered in the design and specifications to enable an initial shotcrete tunnel lining to become the permanent shotcrete tunnel lining.

Mar 8, 2011

Copper entering a lead ,smelter in concentrate or from other sources is recoVered as matte and speiss which contain appreciable quantities of lead. The matte and speiss are usually sold to copper smelters to recover the copper content and also any gold and silver in these products, but the value of the lead is largely lost. Some copper plants pay for portion of the lead content, but regarded as a means of recovering lead it is more costly and less efficient than if the lead were recovered at the lead smelter.Because of the value of this lead loss, the metallurgy of copper recovery has assumed greater importance in recent years owing to the rise on the price of lead.Two processes are in use today to produce matte and speiss, namely the iron matte process and the soda matte process developed by the American Smelting and Refining Co. 1 in D.S.A. The latter process is characterised by a higher copper to lead ratio than the older iron matting process.The following analyses are typical of matte and speiss produced at Broken Hill Associated Smelters, by both processes, although the soda matte process is still in a developmental stage and experience indicates that matte and speiss of lower lead tenor can be produced under favourable conditions.

Jan 1, 1951

By Boshou B

In China, there are approximately 3,000,000 million m3 of gas (methane) included in highly gassy mines liable to coal/gas outbursts; the amount of methane pre-drainage possible is estimated at 400,000 - 500,000 million m3. At present, methane drainage has been carried out in 110 mines with a total amount of 19,000 million m3 methane produced during the period of 198 1- 1986. The methane drainage in coal mines of China can be divided into three types: from adjacent seams, from working face seams and from goafs, all with good results. In recent years, general attention has been paid to integrating methane drainage into the mining system but methane drainage from old goafs has to some extent been developed as well.

Jan 1, 1988

By D Reid, A Fourie

The in-pipe treatment of slurries with polymer addition shortly prior to deposition is a noteworthy emerging technology of increasing popularity. Although polymer treatment has been shown to substantially modify and improve depositional and dewatering behaviour in a significant number of cases, the impacts of polymer treatment on geotechnical performance of tailings are less well understood. For example, certain combinations of polymer and slurry type have been shown to result in lower final densities at a given vertical effective stress. Despite these lower densities, polymer-treated tailings often exhibit peak undrained shear strengths consistent with untreated material. However, the sensitivity and/or brittleness of the material may be negatively influenced by the looser state created. Although these changes have been studied, most testing available in the literature was undertaken on relatively ‘fresh’ samples of polymer-treated material. However, significant shear may occur following treatment and prior to the commencement of settling and self-weight consolidation as the material moves down the beach.To study the effects of shearing on the subsequent performance of polymer-treated tailings, a test program consisting of consolidation, triaxial and direct simple shear tests was undertaken on presheared polymer-treated material. Materials used were identical to those used in previously published studies on the impacts of polymer treatment in a ‘fresh’ condition. Shearing of the polymer-treated material generally appeared to lessen the impacts of the polymer treatment process. However, the behaviour of the material when sheared indicated that the polymer was still impacting the behaviour of the material in some respects. The results indicate the importance of the consideration of shearing on material behaviour when planning and designing a tailings deposit where polymer treatment is to be implemented.CITATION:Reid, D and Fourie, A, 2015. Effects of shear on the behaviour of polymer-treated slurries, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 215–224 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

Early in 1930 William S. Robinson, Managing Director of Zinc Corporation Ltd., anticipated a rise in the price of gold and a devaluation of the Australian currency. 'WS', as Robinson was known, formed a.syndicate in London, which later became incor- porated as Gold Mines of Australia Limited (GMA) to invest in gold mining properties in Australia. GMA examined many prospects and subsequently undertook the development of several mines in eastern Australia. The syndicate also held a number of options and several large reservations for gold exploration in Western Australia over which it was proposed to carry out an aerial survey and thorough scien- tific assessment. To do this Western Mining Corporation Limited (WMC) was incorporated in Melbourne on the 2nd March 1933. The founding chairman of WMC and GMA was the highly respected `Collins House' figure, Sir Colin Fraser. The aerial survey was carried out, and a group of eminent geol- ogists from Harvard University examined many prospects and identified several which warranted development. To finance these activities `WS' formed Gold Exploration and Finance Co. of Aus- tralia Ltd. (GEFCA), in London in July 1934. GEFCA ultimately held 95% of WMC and 62% of GMA. The finance came mostly from London based South African mining companies which had been subscribers to his earlier syndicate plus some American inves- tors. (The Group Structure in 1936 is shown in Appendix `B").

Jan 1, 1988

Permeability and fluid pathways in fracture-controlled hydrothermal systems are governed by a dynamic competition between permeability-creation processes and permeability-destruction processes. Permeability evolution is coupled with the evolution of fluid pressure and stress states. Key permeability-creation processes are micro-scale to macroscopic fracture growth, and the generation of damage zones during co-seismic slip on faults or aseismic creep on faults and shear zones. The competing permeability-destruction processes include crack-healing and sealing, compaction and pore cementation. High rates of permeability destruction in hydrothermal systems require ongoing permeability enhancement to sustain high fluid fluxes and ore genesis.   In aseismic regimes, competition between permeability-creation processes and permeability-destruction processes can lead to continuous flow in deep level hydrothermal systems. However, in seismogenic regimes, rapid co-seismic permeability-enhancement is followed by progressive permeability-destruction in the intervening interseismic periods, and leads to episodic flow. The results of high pressure experiments are used to illustrate how pore fluid factors and stress states are dynamically coupled with permeability evolution in hydrothermal regimes. Particularly in the seismogenic mid- to upper crust, large changes in permeability during the seismic cycle govern relative rates of change of fluid pressure around active faults and shear zones. Rapid, post-seismic recovery of pore fluid pressures, relative to rates of shear stress recovery, leads to growth of hydrofracture networks prior to successive fault rupture events.   Pre-rupture hydrofracture networks do not develop where post-rupture fluid pressure recovery is modest relative shear stress recovery. At elevated temperatures, low rates of pore fluid pressure recovery relative to shear stress recovery promote ductile shear failure and grain-scale permeability enhancement within shear zones prior to rupture events.   The influence of pore fluid pressure cycling, shear stress cycling, and deformation processes in controlling the evolution of permeability, flow localisation, and flow anisotropy at the deposit scale are illustrated for mesothermal and epithermal lode gold systems.

Jan 1, 2005

By P Voulgaris

The Osborne Mine commenced production from an open pit in December 1994 with the first ore being hauled from underground one year later. Currently all ore is hauled up a decline by trucks until the shaft system is commissioned in early-1998. The mine is hosted within a multiply deformed and complex sequence of metamorphic, igneous and metasomatic rocks of mid Proterozoic age that are concealed beneath 20-40 metres of Mesozoic sedimentary cover. Epigenetic and largely hypogene copper - gold mineralisation occurs in a close spatial relationship with quartz - magnetite ironstones and is an important example of a significant mineralisation style in the Mt Isa inlier. Life of mine concentrator production, to year end 1997, totals 3.2 Mt of ore at 3.40 per cent Cu and 1.13 g/t Au. Total metal produced was 97 000 tonnes of copper and 2900 Kg of gold (95 600 oz) from some 348 000 tonnes of dry concentrates averaging 28.01 per cent Cu and 6.99 g/t Au. At the start of 1998 OsborneÆs total measured and indicated resource was stated at 11.38 Mt at 3.24 per cent Cu and 1.21 g/t Au with an ore reserve of 11.42 Mt at 2.90 per cent Cu and 1.09 g/t Au. Exploration efforts in and around the mine have been increased since 1996 and have resulted in an early success, with a 28 per cent increase in ore reserves since mine start-up, and the establishment of a 1.5 Mt inferred resource open to depth. During 1997 the performance of the concentrator has exceeded expectations with throughput having been increased to 1.45 Mt per annum. The Mining Cycle at Osborne has proceeded from discovery through feasibility and is currently seen to be in the latter part of the development stage and/or the early part of an expansion stage. This paper will describe the role of geology and exploration within these stages and will highlight how a number of key interpretations and decisions based on geology have both favourably and unfavourably affected the project.

Jan 1, 1998

By I Villalba

The need to continue the development of the Ensham mine has led to blast up to 75 m to the Eastern side of a water dam in the vicinity of Ramp 23. The water dam wall is exposed to blasting over a distance of approximately 500 m. The first decision was to determine that the existing rock pillar between the Eastern side of the water dam and the blasting operations may not be less than 75 m in order to minimise the damage that the blast could generate to the dam wall. It was also necessary to define blasting practices to minimising the blast damage to the rock properties of the dam wall and to avoid adverse effects from vibration and gases generated by the detonation on structures.For this purpose analytical designs and test blasts were conducted to assess the ground vibration attenuation within the rock pillar. From this analysis, it was concluded that the best practice to reduce the rock damage was to create a zone of fractured rock adjacent to the side of each production blast. This fractured zone would create an effective filter both for vibration and for gases generated by the blast. This zone of fractured rock was created by firing two buffer rows. In terms of pattern size and powder factor the two buffer rows were designed just to generate a fractured rock zone. To date approximately 500 m have been excavated along the eastern wall of the water dam where each production blast was preceded by a Trim blast. This practice has given good results with regard to minimising the damage generated by production blasting.

Nov 8, 2011

The Resource Management Act has been in force now for approximately ten months. This Act, and the Crown Minerals Act which accompanied it, have substantially changed the manner by which mining operations and other resource uses obtain access to resources and are subject to controls of their environmental effects. This paper briefly summarises the key elements of the regulatory provisions of the Resource Management Act. It identifies the types of resource consents required, and discusses these and procedural matters in relation to mining in Otago. It addresses the transitional provisions and highlights inconsistencies and difficulties in the implementation of these provisions. This paper identifies potential future developments in the planning and regulatory environment relating to mining in Otago.

Jan 1, 1992

By Kareise G. J, Leung K

The McArthur River (HYC) deposit, located in the Northern Territory of Australia, was discovered by Mt Isa Mines Limited geologists in 1955. It is one of the largest sedimentary stratiform zinc-lead-silver deposits known. Previous attempts to exploit the deposit have been thwarted by its geographical location, the capital expenditure required to establish an operation and the fine-grained nature of the mineralisation. The steeply dipping western margin of the deposit is covered by up to 25 m of overburden, and lies beneath the McArthur River and its flood plain. Dips are eastward, with the eastern edge of the deposit at a depth of about 400 m below the surface. The average thickness of the deposit is 55 m, and it covers an area of about 1.8 by 1.3 km. Seven stratiform orebodies are interbedded with sedimentary breccia, tuff and poorly mineralised siltstone. Mineralisation consists of finely intergrown sphalerite and galena, hosted by pyritic siltstone of the middle Proterozoic McArthur Group. Selective underground mining of the lower orebodies will extract more than one million tonnes of ore per annum. The dip of the mineralisation demands that mining will be by way of apparent dip room and pillar. Declines will provide access and haulage, and wherever possible development will be in ore. Initially, haulage will be by trackless diesel powered trucks, but these will be replaced by a conveyer system. A single zinc-lead-silver concentrate will be produced from a simple flowsheet. This flowsheet has been developed in the laboratory and demonstrated during an extensive pilot plant campaign. A single stage SAG mill will be utilised to grind the ore down to a P80 = 45 ltm (80 per cent of particles passing 45 ¦rn. Conventional flotation cells will produce a single rougher concentrate that will be reground to No

Jan 1, 1993

Burra was the largest metalliferous mine in Aus- tralia between 1845 and 1860 and employed as many as 1000 men and boys. The workforce was predominantly Cornish, Burra being the first con- centration of Cornish folk in Australia. The sur- face and underground mining operations were typically Cornish and virtually all positions of responsibility were held by Cornishmen. Beam pumping and winding engines were imported from Cornwall and housed in traditional Cornish engi- nehouses. Burra had the first significant number of beam engines in Australia: six were installed between 1849 and 1861. These engines, ranging in size from 20 inches to 80 inches in diameter, were used for pumping, hauling, and driving Cornish roll crush- ers and dressing machinery. Derelict enginehouses of the great beam engines are a striking reminder of former mining activity in Cornwall and South Australia. In South Aus- tralia about 35 enginehouses were erected between 1848 and 1887, of which eight still remain, three of them at Burra (Figure 1). These remain as a tangible link with the Industrial Revolution.

Jan 1, 1987

By H Kurth

"The focus of this paper is on measuring the composition to improve mill feed quality to minimise the processing of waste, optimise process performance, reduce processing costs and minimise the generation of tailings.Technologies used since the 1990s in the cement and coal industries for measuring conveyed materials have been operationally proven and effectively derisked. Despite this the acceptance by the minerals industry has been very slow except in iron ore. Real-time penetrative full stream measurement using prompt gamma neutron activation analysis (PGNAA) for multielemental analysis and microwave transmission for real-time moisture analysis provide representative, tonnage weighted dry weight per cent results on a minute by minute basis. Analysis is unaffected by particle size, dust, layering/segregation, mineralogy and belt speed. The technologies are explained and performance examples given. The benefits derived from real-time compositional analysis are predicated upon a good understanding of deposit geology, mineralogical associations, waste to ore interfaces, amenability to mining, metallurgical processes and downstream customer requirements. Processing may include basic preparation in the case of direct shipping ores, minor beneficiation using simple upgrading methods, or concentration using more complex processing systems such as flotation, leaching or many others. The value of real-time data from primary crushed conveyed flows, using analysis of increments smaller than a single haul truck’s load, is very beneficial in process plants aiming to reduce waste processing, increasing feed grades and increasing metal recoveries. Grade variability can be utilised to divert conveyed increments of waste, direct shipping ore (DSO) quality material bypassing beneficiation, and subeconomic material amenable to upgrading diverted for further preconcentration by particle separation (sorting, heavy medium etc). Paybacks of a few months have been commonly achieved where the real-time technologies have been applied in the minerals sector. The paper outlines proven applications and case studies and proposes some innovative applications.Citation:Kurth, H, 2016. Measuring and Utilising Ore Quality Variability Using Real-time On-belt Elemental Analysis to Improve Mill Feed Quality, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 239–244 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By S B. Sheldon

Wall control programs tend to be expensive and consequently require financial justification in order to get approval for the expenditure required. The difficulty faced in getting this approval is that the outcomes of a wall control program are all subjective – a prediction of wall stability and what the wall would do with and without the program. Determining a net benefit is difficult and often justification of a wall control program is based on gut feel, history and a good selling campaign to build a perceived need.This paper outlines a simple solution to this problem by applying risk management principles to wall control. The process is to identify the risks to the operation associated with current wall conditions and then build a risk database for different potential scenarios for each risk. A financial impact is assigned to each risk scenario to complete the database. A consequence and likelihood analysis of each of the risks is undertaken and a formula applied to estimate the projected cost to the operation for the current risk profile. The process is repeated for the predicted wall control conditions after the application of the wall control program. A successful wall control program will reduce an operation’s risk profile so this projected cost should be less than that calculated for the current scenario. The difference in the two projected costs is the value that the wall control program has produced and this value can be used to determine the net financial benefit potential for the wall control program.This methodology can also be applied to other improvement programs that focus on risk reduction such as vibration control.

Nov 8, 2011

By J Stipcevich, N Patel, J Faithful5, S Narendranathan, L Tatnell4

ENGIE, the current owner and operator of the Hazelwood Open Cut coalmine, are in the process of rehabilitating the mine site in preparation for mine closure. Bucket wheel excavators (dredgers) used during coal mining operations are in the process of being demolished, which involves the controlled felling of dredger components using explosives. With the mine located in close proximity to the Morwell township and other critical public infrastructure, it is crucial that the use of explosives and the possible implications for mine stability is well understood. The felling of Large Mining Equipment (LME) will apply an impact load immediately to the underlying coal benches with the adjacent coal batters potentially at risk also of adverse slope stability impacts. This paper presents the 3D stability modelling methods employed to successfully assess the potentially adverse stability implications associated with LME collapse.

Jun 21, 2022

This paper describes the technical development of the Newman beneficiation plant over its 23 years of operation and how this development relates to the mine ore reserves of high-grade and low-grade ore. It also discusses the importance of the beneficiation product grades in the overall blending of shippable products from a range of mines to optimise overall ore resource utilisation. Also discussed is the importance of the ore reserve reconciliations in resource utilisation. Data is provided on the capacity and quality improvement results of the plant upgrade, carried out in 1999. This shows how the original capacity upgrade targets have been exceeded and the additional quality benefits that have been obtained from this capacity.

Jan 1, 2002