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By Greenwood AG

Research into cemented rock fill at Mount Isa Mines Limited since 1992 is described. The key mechanisms controlling segregation during stope filling with cemented rock fill are described and include the gravity flow mechanism which is described in detail. Examples are provided to demonstrate these mechanisms. Comparisons are made between Mount Isa Mines' cemented rock fill and slurry-based cemented rock fills. Recent backfill stability modelling using a three-dimensional finite clement program is described.

Jan 1, 1998

The paper reviews some characteristic features of feasibility studies and discusses the need for a wide scope at the pre-feasibility stage. The performance of recent Australian gold mines against the predictions contained in their respective feasibility studies is examined, resulting in a recommendation that feasibility studies need to be improved The advantages to be gained from having a feasibility study reviewed by an independent authority are discussed, and some of the reasons for using consultants are listed. Two examples of successful optimisations in the early stages of pre-development studies are described briefly and the benefits achieved are presented. The paper concludes that feasibility studies need improvement to enhance the confidence of investors in the mining industry.

Jan 1, 1991

By D P. Sainsbury, J Western, B L. Sainsbury, V Mutton, P E. Petrie

Remnant rib pillars at Castlemaine Goldfields Ltd’s Ballarat Gold Project have been sterilised by the placement of loose rock fill in production stopes. The application of selectively injecting low-viscosity grout into the backfilled stopes to form a stabilised material has enabled recovery of the previously sterilised pillars. This paper outlines the engineering design, quality control and quality assurance program implemented to ensure the safe and efficient recovery of the rib pillars. The successful program included laboratory testing, numerical exposure stability modelling and in situ monitoring.CITATION:Sainsbury, B L, Sainsbury, D P, Western, J, Petrie, P E and Mutton, V, 2014. Pillar recovery adjacent to stabilised rock fill at the Ballarat Gold Project, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 77–86 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By Buisman C. J N, Koch R. O

Soil and groundwater beneath the Budelco zinc production plant at Budel-Dorplein (The Netherlands) are contaminated with metals and sulphate. To avoid contamination of nearby drinking water aquifers in the very distant future, a geohydrological containment system (GCS) and a microbial treatment plant for extracted contaminated groundwater have been developed. As a first step in the design of the system groundwater data from over 150 wells and geological profiles were used to model geohydrological conditions beneath the site. Several configurations of water-extraction wells were deduced from the model. Data gathered during additional fieldwork were then used to improve the model. Finally results that were calculated for the various configurations were used to select an optimal groundwater containment system. Currently some 5000 m3/day groundwater are extracted from a combination of 12 shallow and deep wells. Heavy metals and sulphate have to be removed from the extracted water before it can be discharged into the river system or used as process water. Several water treatment methods have been studied and pilot-tested at the site. The preferred and selected process is based on the activity of sulphate reducing bacteria (SRB) and combines sulphate removal and heavy metal removal in one single step. The anaerobic bacteria reduce the sulphate to sulphide resulting in the precipitation of metal sulphides. A pilot plant gave promising results and a commercial-scale plant has been designed. The proposed design has been tested in a demonstration plant which included all main process units. Test results for all process units are presented. The collected information was then used to optimise the design of the commercial-scale plant. Special attention was paid to automation and safety items. Construction of the plant was finished in May 1992. Start-up, commissioning and operational experience are reported. The concentrations of metals and sulphate in the effluent of the SRB water treatment plant are well within the limits set by the authorities for discharge to public waters.

Jan 1, 1993

By Tarrant GC

Cement and resin encapsulated tendons are widely used in the stabilisation of mine roadways. One of the main factors in controlling the efficiency of the reinforcement is the ability of the tendon to generate load in response to rock deformation. The analysis of field data from instrumented reinforcing tendons complimented with extensive laboratory investigations have more accurately defined the mechanisms by which load generation occurs. The role of reinforcing tendon profiles, hole geometry and encapsulation medium properties in controlling the reinforcement stiffness and capacity are discussed. The results of the investigation have implications in both the design of rock reinforcing systems and the optimisation of encapsulation mediums and tendons.

Jan 1, 1992

Traditional techniques for extracting pillars in thick underground coal seams in India are reviewed. Problems encountered are principally control of roof strata and low recovery. Recently developed mechanized methods and projected newer techniques are discussed.

Jan 1, 1986

By Ruston R

When coal mining first commenced in Australia, the principle objective was low cost production with development directed toward recovery of 'easy' coal. Future expans- ion of these early mines into major under- ground operations was neither envisaged nor planned. As the demand for coal grew, these mines were expanded to increase output. however, the absence of initial ventilation planning brought about ad hoc systems wh;ch required continual repair and upgrading. These systems proved satisfactory in the short term because the majority of undergrouni coal mining operations were carried out at relatively shallow depths where gas emission rates were low. By comparison, coal is now being won at depths exceeding 500 metres with a corresponding increase in gas flow from the working seams and adjacent strata. The following paper addresses, firstly, the planning and institution of a ventilation system in a mine where previous inefficiencies were many, and secondly, the value of pre- planning a mine ventilation system in the early stages of mine development, and the need to continually review and upgrade the plan to account for unforeseen ^hanges.

Jan 1, 1983

This paper examines the latest advances in mine drive and motor systems. In the last decade, the drive technology employed for large mine winders has migrated from the traditional dc technology to ac motors with cyclo convertor drives. Recent advances in pulse width modulation (PWM) drives have resulted in these being applied to large winder drives. While having many advantages for the winder system, the PWM drive must be carefully designed to ensure long-term reliable operation. When combined with induction motor technology, the PWM drive presents the ideal solution for winder drives. This paper examines the factors in choosing a suitable PWM drive for a winder installation. Factors under consideration include: winder duty cycle, drive rating restrictions, choice of power semiconductor device, cooling, and low speed operation.The cage induction motor is the motor of choice for large winder drives and has a number of advantages over the synchronous motor. The induction motor is ideally suited to integrated winder applications where the motor is built inside the friction drum, as installed at WMCÆs Olympic Dam site. The challenges of integrating the induction motor into the friction drum will be detailed, including: assembly, ventilation, air gap adjustment, and position sensors.

Jan 1, 2005

By Griffiths L, Marshall P

fhis paper describes investigations into drainage of gas from the solid to control outbursts. Initial studies conducted on drainage of shear zones showed that, given enough time, these can be successfully drained. Once drained, they can be intersected and driven through without any activity of outbursts. The results of programme of investigations to determine parameters for drainage from the solid show that gas flow rates from the Bulli Seam on the average are about 2 litres/min/metre length of borehole. But when shear zones are intersected, the flow rates could be as high as 8 litres/min/ metre length of hole. Shear zones can be picked up from pressure measurements 50 - 60 m away and this could give sufficient time to drill through these zones and drain them in advance. Systematic drainage of Bulli Seam at West Cliff Colliery could eliminate or reduce frequency of outbursts considerably. At present drainage holes are being drilled systematically in the seam, with drainage installations on the surface. Gas purity of 80% methane is being delivered at the surface plant.

Jan 1, 1980

Epicentres of recent shallow earthquakes in the region (3-12¦S, 126-150`E) were plotted to identify the various plate boundaries in the region, in particular the southernmost one marking the northern edge of the Australian plate. New and published fault plane solutions were examined to determine the style of faulting and state of stress along the Australian plate boundary. From east to west the boundary is first a subduction zone along the Solomon Islands, then a spreading centre across the Solomon Sea, a zone of compression and left lateral strike slip along the Papua Peninsula, almost pure thrusting across the centre of New Guinea and lastly left lateral strike silo through Irian Taya to the outer Banda Arc. The principal stress is very consistent, trending NW to NNW in a near horizontal plane, from the triple junction of the Pacific, Solomon Sea and Australian plates in the east to the Banda Sea in the west. Only along southern Solomon Sea plate margin which is a divergent boundary, is the stress different in type and direction.

Jan 1, 1987

The winning and upgrading of mineral raw materials necessarily includes size reduction, which serves the liberation and production of marketable products from highly valuable and bulk materials. For crushing, the following factors can be duly accounted for depending on material type and the selection of the suitable machine: ò producing a particular size distribution, ò producing a particular grain shape, ò selective comminution, ò gentle comminution, and ò producing a size range required by a specific process and/or for a specific product.

Jan 1, 1993

The Douglas mineral sands deposit is located 75 km north of Hamilton in western Victoria, Australia. The deposit was discovered in the late 1990s by Basin Minerals Limited and purchased by Iluka Resources Ltd in 2002. Prestrip mining commenced in December 2004, with ore mining commencing in August 2005. Douglas is the first of several projects being implemented by Iluka Resources Ltd in the Murray Basin, with all heavy mineral concentrate planned to be treated at the companyÆs mineral separation plant in Hamilton. The mineralisation at Douglas lies along the south-eastern margin of the Murray Basin. It is hosted by marine Pliocene Loxton-Parilla Sands and consists of three discrete deposits; Bondi Main, Bondi West and Bondi East. The mineralised sediments dip at a low angle to the west and lie unconformably beneath a veneer of top soil (50 - 100 mm) and subsoil (up to 600 mm) and between three to 12 m of overburden. The barren overburden, characterised by high clay content (<53 ¦m material) generally provides a stark contrast to the sandy ore, which is between 1 m (parts of Bondi East) and 15 m (Bondi Main) thick. Both overburden and ore are removed utilising standard dry mining techniques using both scraper-bulldozer and truck-excavator combinations. All ore is delivered to run-of-mine (ROM) stockpiles before being reclaimed by front end loader into the processing plant. Grade control at Douglas is based around visual dig control aided by high precision survey, which enables accurate reference to the resource drilling and block model data. Vertical excavator faces, inclined scraper faces plus regular test pits and trenches provide opportunities for in pit mapping and sampling. This data is used to refine not only the resource estimate for Douglas but also the drilling, interpretation and resource modelling methods used for similar deposits across the basin. The foundations of the geological reconciliation process at Douglas are the in pit surveys undertaken each time the mining fleet has completed building a ROM stockpile. These surveys and the subsequent interrogation of resource models enable robust estimations of the heavy mineral content of the stockpiles, which are subsequently used to predict the daily input grades into the plant during their reclamation. Reconciliation of this daily data is then undertaken at the end of each month against metallurgical production data and plant balances. Learnings and results from the reconciliation process are used to further refine subsequent resource models and modelling methods.

Jan 1, 2009

By Grano S. R, Kilgariff B

The Renisun Tin concentrator treats an ore containing I's per cent till as cassiterite and 22 per cent sulphur in a range of sulphide minerals. predominantly pyrrhotite. The sulphide minerals are removed by flotation using copper sulphate (CuS

Jan 1, 1997

By Jankowski P

The Bannockburn gold deposit is located 67 km north-west of Leonora in a poorly exposed part of the Norseman-Wiluna belt of Western Australia. The deposit consists of narrow, complexly shaped orebodies which have presented a challenge to find successful grade control and mining methods. The deposit also presents an opportunity to examine in detail the geology of this part of the Norseman-Wiluna belt.This paper discusses the geology and structure of the Bannockburn gold deposit as well as the grade control and mining systems developed to define the ore and extract it with minimum dilution. We discuss the different techniques employed for grade control in the past and their shortcomings, and the evolution of the present system of doing grade control in cross section from blast hole assays.

Jan 1, 1993

By Williams P

The assumptions made in conventional (Terzaghi) consolidation theory are not met in a tailings deposit. Finite or large strain consolidation theory must be employed. The paper describes such a consolidation model and its application to the design of tailings impoundments, water management systems, and long term rehabilitation.

Jan 1, 1990

By Boyd D. M

Minor magnetic anomalies which may be un represented on a magnetic contour map can be extracted from the original survey data and plotted by the described method to provide a rapid interpretation of the magnetic survey, provided that the data has been recorded digi- tally on magnetic tape. The example used comes from 40 kilometers south of Charters Towers, Queensland.

Jan 1, 1977

The Great lady gold deposit presented the challenge of providing a new grade control system for an usual type of orebody in the Eastern Goldfields. Mineralisation occurs as secondary enrichment about a quartz sand - granite saprolite contact 30m below surface. The ore horizon, which averaged 2.5m thickness, was near-horizontally disposed in contrast to the typical steeply dipping, shear hosted deposits of the region. A trial mining operation was undertaken on the richest, most continuous portion of the deposit to test the economic viability of this type of orebody. Controlling and minimising vertical ore dilution was considered crucial to the profitability of the operation.An understanding of the grade distribution combined with the practicalities of mining produced a grade control system which allowed for the mining of 1/2rn composited grades on level lm benches. Ore mining was combined with strict monitoring of levels, truck destinations and ore boundaries. Ore reconciliation results showed this system to be effective.

Jan 1, 1990

Mining software systems have provided a basis for integration of resource, survey, and design functions. They can similarly provide a basis for incorporating ground conditions into the process.Exploration and mine geologists have a prime role to play in this process, extending their responsibilities further across the geological spectrum, into exploration of ground conditions, analyses of results, and assessments of their implications for mining. Ground conditions are as much a part of the geology of a prospect or mine as its mineralisation, and can have critical imnlicationa for mining.

Jan 1, 1993

By Hebblewhite B, Humphreys D

An experimental mining project has been carried out in the Collie Basin to demonstrate the safe operation of total extraction mining techniques in the underground mines of the basin. To achieve this, it was necessary to design and install a means of controlling or removing groundwater so that goafing of the overlying strata could be safely achieved as part of the mining operation. The site chosen for the experiment was a triangular panel adjacent to Western No 6 (WD6) underground mine, which includes the 3 to 4 m thick Wyvern Seam beneath 130 to 180 m of overburden. The test area abuts a major fault on the downdip side. The overburden and underburden sequences include several horizons of permeable sandstones which form major aquifers. Water problems have long been recognized in all underground mines in the Collie Basin, and have previously prevented the successful application of total extraction mining. Following extensive hydrological investigations, dewatering and depressurization systems were designed to dewater the immediate roof aquifers and to depressurize aquifers higher in the sequence and in the floor. This would enable stable roof conditions to develop and controlled goafing to be achieved. The roof dewatering/depressurization procedure involved a combination of in-mine vertical roof drainage holes and conventional dewatering bores constructed from the ground surface above the mining trial area. The dewatering system was installed and operated for 29 months before the commencement of mining. Mining was eventually successfully completed in two trial panels using a retreat Wongawilli extraction system using bridge conveyors and continuous miners. Water inflow into the mine workings was channelled to a constructed sump area at the lowermost corner of the panel and pumped to the surface via vertical sump bores. The dewatering and depressurization measures adopted were successful in permitting the first controlled and systematic total extraction recovery of coal from the Collie Basin. This trial mining exercise demonstrated the potential for increasing substantially the recovery of coal from the Collie Basin, where previously recovery rates of around 30 percent from underground mining were commonplace, using only bord and pillar methods.

Jan 1, 1988

By Nguyen G. H, Graham J

A laboratory-scale fluidised-bed roaster has been used to examine the effect of temperature and duration of roast on the morphology of the calcine produced from a pyritic gold-bearing concentrate. Two mechanisms of oxidation, which depend on the roasting temperature, have been identified. For samples roasted below 550°C, direct oxidation of the sulphide occurred to form hematite with a porous fine-grained concentrically-layered texture. The surface area of the calcine increased with an increase in roasting temperature in the range 400 to 500°C. For samples roasted above 550°C, the first reaction was the evolution of sulphur vapour to produce pyrrhotite, which underwent increasing grain growth as the roasting temperature was increased. This had the effect of decreasing the surface area of the calcine. The pyrrhotite was subsequently oxidised to produce hematite.Leaching studies using cyanide solution indicated that gold extraction around 95 per cent was achieved at temperatures of 500°C and above, with optimum extraction, taking into account rate and cyanide consumption in the range 550 - 700°C. Hence recovery did not decrease with decrease in surface area of the calcine. Observed gold in leached calcines was mainly enclosed in thin oxide walls of the hematite, with minor quantities enclosed in quartz and silicate minerals.

Jan 1, 1995