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By Bishop I, Toon S

To determine whether 130 felt earth tremors around Edwinstowe, Nottinghamshire U.M, which also experienced severe surface fissuring, were caused by coal extraction, a surface seismometer array was established around Thoresby Colliery. Over the next year, 785 microseismic events were detected. The spatio- temporal seismicity patterns are clearly associated with the commencement, continuing extraction and closure of faces. Of particular note are events which locate at the surface and appear to be related to the active fissuring. Events occur within days of commencement of production and cease when production finishes, with good correlation between face advance and hypocentral position. Naturally occurring microseismic events have also been detected up to 1 km ahead of active longwall faces in the Midlands using triaxial geophone packages grouted into the seam together with a surface seismometer in the top of the borehole. The quality of these data were very high and guided waves can clearly be seen with the dispersive characteristics associated with seam waves. In one experiment more than 2000 events were detected in only two days of monitoring even in a relatively noisy surface environment. This paper demonstrates how very accurate locations (5 10 metres) can be generated using three-component digital data from only one borehole. The surface seismometer and the borehole P-wave onset can give extra precision for the height of the event relative to the seam. The event distributions give a dynamic, three-dimensional image of the developing patterns of fracturing above, below and ahead of the longwall face with important implications for roof control, subsidence prediction and gas Migration.

Jan 1, 1992

By J Chßvez, J Rosa del Castillo, J Rui

Environmental Impact Assessment (EIA) and Feasibility Studies (FS) were carried out to evaluate the potential use of treated acid mine drainage (AMD) occurring at the Kingsmill Tunnel in the Central Andes of Peru. The 11 km long tunnel drains the underground works of the Morococha Mining District and discharges about 1.25 m3/sec of AMD directly into the Yauli River in the Amazon Basin. The communities living downstream cannot use the Yauli River water due to its low pH and elevated concentrations of metals (eg Cu, Zn, Fe, Mn, As, Cd) and sulfate. Studies carried out for this project included technical feasibility, EIA, economic viability and social impact assessment phases. During the æTechnical FeasibilityÆ phase, the treated AMD was produced by simulating a high density sludge (HDS) lime neutralisation/ precipitation process and was evaluated for various potential uses. Mining companies located in Morococha, in particular Centromin Peru SA, and the Water Works Company of the City of Lima (Sedapal) collaborated with Golder Associates during the studies. The Canadian International Development Agency (CIDA) provided the financial assistance. The results of the physical, chemical, biological and toxicological analyses demonstrated that the AMD could be sufficiently treated to be potentially used to supplement the drinking water supply of Lima, and for agricultural (eg irrigation and livestock) and recreational purposes. Process design and scale-up parameters were also determined for implementation of the full-scale treatment facility at the site. The use of the treated AMD as a drinking water supplement would be economically feasible.

Jan 1, 2003

By Schmincke H-U

The Pleistocene basanite-tephrite Rothenberg cone complex was built by an alter- nation of strombolian and phreatomagmatic phases of explosive eruption. Two main centres, on a one km long NNE-trending fissure, were active during its construction. The strombolian deposits from three discrete facies corresponding to the crater-fill and inner wall and outer wall environments on the cone. The outer wall facies consists of an alternation of 1. 'normal' coarse-grained, relatively well- sorted lapilli and bomb beds, and 2. finer-grained poorly-sorted lapilli beds. Evidence suggests that the former was pro- duced by open-vent lava fountaining, with balanced magma supply and discharge rates, and the latter are the products of eruptions during partial blockage of the vent, by collapse of wall-rock, and formation of a degassed crust on the magma. The resulting explosions there- fore ejected a mixture of fresh actively ves- iculating magma, older partially degassed lava and material recycled from the wall of the cones. The phreatomagmatic deposits are an alternation of moderately-sorted fall beds and thinner ash-rich pyroclastic surge and rain-flushed units. The clast populations are much more diverse than strombolian ones, including abundant wall rock fragments from 0-100 m depth. The juvenile (magmatic) particles range from highly vesicular scoria to dense 'bread-crusted' clasts, and contain abundant small wall rock inclusions. The phreatomagmatic phases are products of explosive interaction of small batches of magma with shallow groundwater. Vesiculation of this magma played a small but significant role throughout the fragmentation.

Jan 1, 1987

Porphyry type mineralization of Lower Cretaceous age in eastern Queensland has been recognized only from the easternmost part of the northern New England Orogen (Day, Murray and Whitaker, 1978), within the northern Yarrol Province (Horton,1982). Recent work about the Mt. Suthers (Pb, Zn, Ag, Cu, Au), Lug-e-nor (Cu, Pb, Zn, Ag, Au, Mo), and German Tully (Cu, Au, Bi) prospects suggest that there has been a phase of porphyry type mineralization within the Gympie Province, of Lower Cretaceous age, overprinting earlier Permo-Triassic phases. About the Mt. Suthers Prospect surface samples of shallow, medium to heavy textured soils derived from marine sedimentary rocks of Permian age, and extrusive and intrusive igneous rocks of intermediate composition and Triassic age, were analysed for Cu, Zn, Pb, Co, Cr, Ni, Fe, V, Mn and Ag. Whereas strong iithological control determined the distribu- tion of Cu (diorite) and of Cr, Ni, Fe and V ,sedimentary rocks), the distribution of Pb, Zn, Ag and of Cu, were determined by mineralization of faults by a cavity fill hydrothermal process. Gold is associated with the Pb, Zn, Ag mineralization. Co and Mn showed distributions independent of lithology and structure. The fault controlled style of mineraliz- ation at Mt. Suthers is repeated at other localities to the south; Calgoa, Marodian, and German Gully. Relative dating of structural features and isotopic dating of nornblende porphyrites (134-135 m.y.) near and related to those mineralized at German c;ully suggest a previously unrecognized phase of porphyry copper style mineralization in south-east Queensland of Lower Cretaceous age (Fig. 1).

Jan 1, 1987

By Y A. Stepanyants, J Crawford

A practical field method for determining the maximum value of the intrinsic oxidation rate, Smax , of sulfidic materials in waste rock dumps is proposed. Knowledge of the intrinsic oxidation rate of sulfidic materials distributed in a dump is necessary for predictive modelling of oxidation and pollutant generation over time. The suggested method uses the fact that drilling waste rock dumps to install probes for monitoring temperature and oxygen concentration causes large volumes of air to be injected into a dump by the drill rig. By measuring the rate of decrease of oxygen concentration along the length of a borehole immediately after installation, it is proposed that Smax can be calculated at different depths. The aims of this work were: to derive a simple, practical formula for the estimation of Smax from the oxygen concentrations measured over time, based on some simplifying assumptions; to use a two-dimensional numerical model that incorporates all the necessary physical processes to model the behaviour of an aerated dump over time for a reasonable range of dump and material parameters; and to compare the results of the two approaches to assess the validity of the simple formula as a method for estimating Smax. It has been found that the technique can provide reliable estimates of Smax when the value is of the order of 10-7 kg(O2) m-3 s-1 or greater. At the lower end of the range however the radius of the zone aerated during drilling becomes an important parameter and further work has been recommended to investigate this aspect of the method.

Jan 1, 2003

Brand se Baai, on the North-Western Cape Coastline of Southern Africa, is the site of the Namakwa Sands Limited Heavy Mineral Sands Mining Operation. The mine is a 14 000 000 tonnes per annum open-cast strip-style mining operation using truck and excavators to mine the sand. The orebody consists of relatively unconsolidated sands reworked by fluvial, marine and aeolian mechanisms. The total orebody includes three primary ore types, namely the Red Aeolian Sands, the Dorbank (a hardcap layer) and the Orange Feldspathic Sands, which forms the bulk of the resource. Mine planning and scheduling is done using a 50 m + 50 m variable bench height system with three primary bench heights. The Aeolian and Dorbank each have a bench that varies with their thickness of up to a maximum eight metres and the Orange feldspathic sand, a standard bench height of eight metres. For a number of years Namakwa Sands used a complex 2D, Datamine Based, macro system to perform the resource evaluation and mine design. As the mining operations expanded it became clear that a complete system redesign was required to cope with the increasing operational pressures coming to bear on the old system. The biggest challenges facing any replacement system are the sheer scale of the mining operation (16 km long and 7 km wide resulting in a minimum of 30 000 individual 50 m + 50 m mining blocks), the size of the geological data files (up to one gigabyte) and representing the benching system accurately (as the benches follow the topography and are not horizontal). In addition to these large-scale issues, the ability to run multiple mine design scenarios was required, an aspect which the old system was unable to perform adequately. Based upon these primary difficulties, a new business process was developed which required a complete rethink of the mine design methodology as well as the creation of a new system to deplete the resource model, produce monthly reconciliation evaluations and create a ultimate pit limit based on the operations mining cost model. Using a system based on the Earthworks Mine2-4D Mine Design and Scheduling System (with its mine design and scheduling specific tools), as well as a small, customised program, massive time-savings have been made. It is now possible to run several life of mine scenarios in the same timeframe that a single life of mine run took under the old system. This paper will present the methodology and business decisions behind the new Namakwa Sands system, and detail the restructuring and development used to deal with the large data set sizes and long processing times inherent in the old system. Future enhancements to the system that will make it more generically applicable to open-cast mining scenarios will also be dealt with.

Jan 1, 2003

By R Williams, P Kohout, J Comins

The Northside Storage Tunnel (NST) is the largest tunnelling project ever undertaken in Sydney. The tunnel extends deep underground from the western bank of the Lane Cove river to the North Head sewage treatment plant (STP), with a branch tunnel from Scotts Creek connecting to the main tunnel under Tunks Park. The aim of the tunnel is to intercept wet weather overflows from four key points along the northernsuburbs ocean outfall sewer (NSOOS) and provide short-term storage and transfer of sewage to NorthHead STP for treatment prior to discharge to the ocean through the deep ocean outfall. The project was an ambitious undertaking by an alliance between the client Sydney WaterCorporationand the engineering firms of Montgomery Watson, Connell Wagner and Transfield to design andconstruct approximately 20 kilometres of tunnel, tunnel declines and shafts in just over three years. In order to achieve this tight timeframe construction of the NST has been undertaken simultaneously at seven construction sites located across the northern suburbs of Sydney. As with most tunnelling operations, tunnel boring machines (TBMÆs) and roadheaders dominated the excavation activities. Tunks Park and North Head STP are the major tunnelling sites. An access decline was excavated using roadheaders at both of these sites to facilitate tunnelling using TBMÆs. Three TBMÆs 3.8 m, 6.0 m and 6.3 m diameter) were launched from Tunks Park and one TBM (6.5 m diameter) was launched from North Head. At the overflow interception sites of Scotts Creek, Lane Cove River and Quakers Hat Bay two vertical shafts known as drop and access/ventilation shafts were constructed. These shafts would provide the linkage between the existing sewer and the tunnel. As their names suggest the drop shaft would convey the wet weather sewage overflows to the tunnel while the access/ventilation shaft would provide access during dry weather and ventilation during a filling event. The fourth overflow site of Tunks Park would use the tunnel decline as its link to the tunnel. Originally these shafts were to be excavated using the raise bore method. This technique however, is entirely dependent on the TBMÆs reaching the shaft locations at the specified time. This was not the case at two of the three shaft excavation locations and top down methods of excavation such as, a percussive cone fracturing (PCF), blind bore, mechanical excavation and drill and blast were investigated to ensure the project met its completion schedule. Traditionally project decisions are dominated by cost and schedule objectives. The contractual arrangement of the Alliance however, required that the objectives of safety, community and environment also be considered in any decision making process. Thus each of these top down methods of excavation were assessed against these five objectives. On considering all of these factors the use of explosives was considered to be the superior technique.

Jan 1, 2001

By M Hourn, D Turner, P Voigt, D Mallah

The GPM Gold Project is located in Armenia, and consists of an open cut mine at Zod, near the Azerbaijan border, and a CIL processing plant at Ararat near the Turkish border. Mining at Zod commenced in 1976, and focused on near surface oxide ores, which overlay deeper refractory sulphides. Historical mining has now almost depleted the oxide ores, and the sulphide content of ore delivered to the processing plant at Ararat is increasing. Gold and silver recoveries through the Ararat plant were declining steadily.GeoProMining, the owners of the project, have expanded the Ararat facility to deal with the increasing sulphide content in the ore. In 2014, GeoProMining refurbished an existing concentrator on site to recover a sulphide concentrate from the ore, and have constructed an Albion ProcessTM plant to oxidize the refractory concentrate. Glencore Technology (GT) provided the Albion ProcessTM plant as a technology package.In July 2014, the progress of the GPM Gold Project Albion ProcessTM Plant was reported (Hourn, Voigt and Turner, 2014). At the time of writing, the construction of the plant was nearly complete. This paper presents an update of project progress, covering commissioning and ramp up of the GPM Gold Project.The commissioning phase occurred over June to August 2014, which included an M3,000 IsaMillTM fine grinding plant, a 6 tph limestone milling plant, a 60 tpd vacuum pressure swing adsorption oxygen plant, a 10 m residue thickener and a 12 tph Albion ProcessTM oxidative leach plant. Since commissioning was completed, ramp up occurred over the following three months with downstream gold recoveries from cyanide leaching reaching over 98%.CITATION:Voigt, P, Hourn, M, Mallah, D and Turner, D, 2015. Commissioning and ramp-up of the Albion Process at the GPM Gold Project, in Proceedings MetPlant 2015, pp 207–219 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By D Fergusson, J D. St George

Highwall stability is a major consideration in optimising opencast mine geometry. It involves assessing the risk of those slope failures that are large enough to have significant cost, safety and/or operational implications. These risks are then balanced against the value of the resource to arrive at an acceptable slope design. Load-deformation models (commonly referred to as ænumericalÆ models) of slopes provide a powerful tool in this decision-making process since they can be verified well before slope failure occurs. This gives the slope designer increased confidence in reviewing designs during excavation, potentially allowing early revision of pit geometry to either increase or decrease safety margins as appropriate. However, these models are not always adopted as they depend heavily on an appropriate choice of constitutive model and material parameters.   A preliminary load-deformation model of a 170m highwall in Solid Energy North (SEN) OperationsÆ Awaroa 4 opencast coal mine in the Rotowaro Coalfield has been prepared. This uses a strain-dependent constitutive model based on laboratory test results, strength parameters developed by SEN and excavation monitoring data. The laboratory testing has included triaxial compression tests on large-diameter fractured samples to characterise the stress-strain response of the closely-jointed soft rock masses that exist in many parts of the mine. Data from the monitoring of a 25m cut made during excavation of a haul road has been used to refine and verify the constitutive model. The resulting highwall model has predicted highwall crest movements corresponding to the excavation of each bench, for comparison with monitored values. Key model outputs are total horizontal movements of about 0.5m near the highwall crest and shear strains of 0.5-0.7% at the locations of potential bedding-parallel shear planes underlying the highwall. Most of the movement is expected to occur as creep rather than as an immediate response to excavation.

Jan 1, 2006

By G Gopinath, R Balachander, H S. Venkatesh

This paper describes in detail the controlled blasting adopted and the measurements undertaken for the successful excavation of large twin tunnels under a shallow cover for a six-lane highway project in India. The tunnels are D-shaped, each 15 m in diameter, and the cover between the tunnels and the existing railway track was about 14 m. These twin tunnel tubes were characterised by two separate three-lane carriageways for each direction of traffic, and were planned with about 25 m of reinforced cement concrete (RCC) portals at the entrance and exit of the tunnels. The major challenge of the project was the blasting of tunnels in rock below an operating railway line. As the tunnels approached the area below the railway line, the ground vibrations were monitored vertically above the blasting faces and on the railway track sleepers. Vibration intensities between those generated from tunnel blasting and those from the movement of the trains were compared, and it was found that the vibrations from blasting were lower than those from the moving trains. Though the permissible level of ground vibration based on the Indian Standard (IS) code happens to be 70 mm/s, the maximum charge per delay was calculated restricting this limit to 50 mm/s. This ensured that the vibrations in the vicinity of the railway tracks never exceeded the prescribed limit of 70 mm/s. The surface ground settlement before and after the blasts were also measured using an optical levelling instrument, which confirmed that there was no significant impact on the surface movements due to blasting. Extensometer readings inside the tunnels showed that there was no deformation in the tunnel. These twin tunnels are now operational and are providing faster connectivity with safety.CITATION:Gopinath, G, Venkatesh, H S and Balachander, R, 2015. Controlled blasting for twin tunnels with a shallow cover under an operating railway line, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 801–808 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By F M. Weir, M Fowler

The design of excavations in rock must, implicitly or explicitly take into consideration the influence of small- and large-scale geological structures. For most sites the complexity of a fractured rock mass is best captured using a 3D fracture system model based on field data. A discrete fracture network (DFN) approach involves stochastic modelling of the ‘smaller scale’, nondeterministic structures. For slope stability or tunnelling projects DFN modelling provides a valuable geotechnical tool for characterisation of a rock mass and identification of likely failure mechanisms.This paper presents a suite of the DFN modelling undertaken for the design of a large open pit in Australia. The proposed pit is to encounter a 160?m thick, high strength, sheared shale unit, which overlies a crystalline basement. DFN modelling was undertaken separately for both the shale and basement units. While the model inputs and development for each unit are briefly presented, the focus of this paper is on the various applications of the DFN modelling.A key advantage of the DFN approach for design studies is its probabilistic application to structural analyses and results. Multiple realisations of the same model were generated for both the shale and basement units, with the stability analysis carried out on each iteration. The generation of a large number of DFN models and analyses allow assessment of wedge volume, factor of safety and proportion of unstable slope for a range of conditions. The DFN modelling at the case study site was also utilised for a number of other purposes. For example, investigation of likely fault lengths in the shale unit and combined rock mass and defect failure. The development of this tool has been influential in improving our understanding of fracture networks for excavation design.CITATION:Weir, F M and Fowler, M, 2014. Rock mass characterisation and analysis for excavation design – a discrete fracture network approach, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 445–456 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By G Hancock, J Lowry, W D. Erskine, D Jones, T Coulthard, M J. Saynor, P Lu

An 8 ha trial landform was constructed in late 2009 at the Ranger Uranium Mine, located 250 km east of Darwin in the wet-dry monsoonal tropics of northern Australia. The objective of the trial, which comprises two surface cover types on a uniform two per cent slope, is to provide long-term data to guide the development by Energy Resources of Australia Ltd (ERA) of its landform closure strategy. The scope of the work program for the landform includes many aspects; however, this paper is focusing on run-off and erosion rates. The run-off and erosion rates are used to assess the long-term geomorphic stability by comparing measured with modelled export rates from a landform evolution model.Monitoring of wet season run-off is undertaken collaboratively by the Environmental Research Institute of the Supervising Scientist (ERISS) and ERA, on four purpose-instrumented 30 m by 30 m erosion plots. Continuous measurements are made in rectangular broad crested (RBC) flumes located at the outflow of each plot, of water level, turbidity (a surrogate for fine suspended sediment) and electrical conductivity (EC) (a surrogate for solutes). Each plot has a tipping bucket pluviometer located near the RBC flume. Bed load is collected monthly.This paper reports the findings of rainfall and bed load from the first two wet seasons (2009 - 2010 and 2010 - 2011) following construction. The field measured loads will be compared with the predictions made by the Cellular Automaton Evolutionary Slope and River (CAESAR) landform evolution model. Initial results indicate that predicted rates of sediment export from the CAESAR model are similar to measured export rates. This provides confidence in the capability of the model to predict stability of the future rehabilitated mine area, especially during the critical initial years following construction. CITATION:Saynor, M J, Lowry, J, Erskine, W D, Coulthard, T, Hancock, G, Jones, D and Lu, P, 2012. Assessing erosion and run-off performance of a trial rehabilitated mining landform, in Proceedings Life-of-Mine 2012 , pp 123-132 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By O van Baalen

The Ernest Henry Mine is a copper-gold open pit operation situated in northwest Queensland, Australia. It is owned and operated by Xstrata Copper, with a current throughput of 11 Mtpa, however, open pit operations are scheduled to cease in mid 2011. The deposit dips approximately 45º and extends for at least another 400 m vertically below the final 530 m deep pit design.Construction and development of a sublevel caving (SLC) operation beneath the open pit was approved in December 2009. The feasibility design requires 39 km of development to be completed prior to production, which will commence in the fourth quarter of 2011. Initial ore production will be trucked and will increase to 3 Mtpa by the end of 2012, after which a hoisting shaft will be used. Ore production will then increase to 5 Mtpa in 2013 and ultimately to 6 Mtpa in 2016.Two 3000 kilo watt of refrigeration (kW(R)) modular refrigeration plants will be installed, as well as two 1600 kW mixed-flow fans capable of a combined flow rate of 780 m3/s at a total pressure loss across the mine of 2000 Pa. The main fans will be installed underground and will exhaust into the base of the pit.The following challenges were faced in the development of the ventilation and refrigeration network:•a relatively steep geothermal gradient,•tropical ambient conditions,•working under a wide pit shell, and•a large underground trucking fleet prior to shaft commissioning.A considerable number of ventilation studies were conducted with later studies extensively using Ventsim Visual™ mine ventilation software to complete the design process of the ventilation and refrigeration networks, including the comparison of several alternative designs. The paper focuses on design challenges prior to the commissioning of the hoisting shaft, and discusses resistance optimisation and occupational hygiene-related design parameters, such as heat and diesel emissions, production level ventilation, main fan selection and location, and refrigeration requirements.

Mar 21, 2011

By N Taylor, P Hewitt

The Northern Beaches Storage Project (NBSP) is part of Sydney Water’s SewerFix™ Program to improve the wastewater system and protect public health and the environment. It was built by the SewerFix Wet Weather Alliance (the Alliance), a partnership between Sydney Water, RPS, MWH, Parsons Brinckerhoff and United Group Infrastructure.The project temporarily stores excess wastewater diverted from the Narrabeen Submain during wet weather. The project considered a below-ground storage facility, which involved constructing a deep tunnel from Brookvale to Fairlight, connecting into the Northside Storage Tunnel and a storage tank, which was subsequently adopted and constructed.The storage tank scheme included a pumping station and inlet and outlet pipes installed by microtunnelling. The storage tank site is in the Brookvale industrial area situated in an area of deep marine sediments overlying Hawkesbury Sandstone at about 30?m below ground. Microtunnelling for the inlet pipe was conducted from a 12?m deep jacking shaft. The jacking shaft and 14?m deep pumping station excavations were carried out from within secant pile earth retaining structures adjacent to existing buildings.Construction activities had the potential to cause settlement of the adjacent buildings. During excavation and microtunnelling the water ingress, adjacent groundwater level and settlement of the adjacent buildings were monitored. The monitoring data was assessed against an action plan, which modified construction activities as required to minimise the risk of damage to buildings from settlements caused by lowering of the groundwater table outside the excavations. The secant pile construction, excavation, microtunnelling and pumping station construction proceeded without incident or damage to adjacent buildings.This paper highlights that tunnel/underground options should be considered during options development, describes the original storage tunnel scheme and presents details of the successful microtunnelling and deep shaft construction adopted on the NBSP.CITATION:Taylor, N and Hewitt, P, 2014. Tunnelling on Northern Beaches Storage Project, Sydney, to improve water quality, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 451–458 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By M Brockman, M Cowan, A Robeson

"Sunrise Dam Gold Mine (SDGM) is located 820 km from Perth, 220 km from Kalgoorlie—Boulder and 55 km south of Laverton in Western Australia. The SDGM main pit had successfully operated since 1997 and was due to be completed during 2012. An opportunity existed to extract the high-grade crown pillar – 600 kt @ 7 g/t for 135 koz by either open pit or underground methods.The crown pillar was the 60 m (vertically) thick remaining part of the high-grade Cosmo orebody between the top of the paste filled underground mine stopes and the planned base of the final open pit shell.There were two major difficulties being considered when choosing the underground or open pit options:a major wall failure in the upper section of the main pit wall directly above the crown pillar restricting access from the base of the open pit to the top of the crown pillarimpact of a high rainfall event while the crown pillar was being mined from either surface or underground resulting in flooding of the underground mine workings.This paper will discuss the following issues:the process to identify and evaluate the risks in both options using knowledge based modelling software; this technique allowed the evaluation of a complex set of assumptions to arrive at the preferred optionremediation of the Watu failurethe selection of the preferred option and the challenges encountered before, during and after the extraction of the crown pillarthe planning and geotechnical work to ensure the safe extraction of the crown pillarsuccessful outcomes transitioning from open pit operation to a solely underground operation.Citation:Robeson, A, Cowan, M and Brockman, M, 2016. A Case Study on the Assessment, Planning and Extraction of the Crown Pillar at Sunrise Dam Gold Mine, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 115–136 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By M I. Pownceby, N A. S Webster, A J. Studer, I C. Madsen, J A. Kimpton, M J. Fisher-White, L Lu

In situ synchrotron X-ray and in situ neutron diffraction-based experimentation have been implemented to characterise the formation of the complex calcium ferrite iron ore sinter bonding phases silico-ferrite of calcium and aluminium (SFCA) and SFCA-I. Experiments were carried out using fine-grained (<20 ¦m) sinter mixtures containing ~77 wt per cent Fe2O3, 14 wt per cent CaO, 3.5 wt per cent SiO2 and 5 wt per cent Al2O3, with diffraction data collected during heating until 1300 - 1350¦C, which was enough to ensure complete melting of the SFCA phases. In the case of the in situ synchrotron experimentation, results showed that altering the nature of the starting sinter mixture (ie substitution of goethite for hematite; substitution of an amorphous Al2O3-based mineral for gibbsite) did not have a significant effect on the thermal stability range of the SFCA phases. It did, however, have a profound effect on the formation and rate of consumption of the calcium-rich ferrite phases C2F and CF, and on the formation mechanisms of SFCA and SFCA-I. The in situ neutron diffraction experimentation is the first described in the context of iron ore sintering, and the observation of both SFCA-I and SFCA formation in the in situ diffraction data represents the first step in achieving the goal of charactering iron ore sinter phase formation in large volumes of industrial sinter starting materials with a wide range of particle sizes (up to 6.3 mm).CITATION:Webster, N A S, Pownceby, M I, Madsen, I C, Studer, A J, Lu, L, Manuel, J R, Kimpton, J A and Fisher-White, M J, 2013. In situ x-ray and neutron diffraction studies of silico-ferrite of calcium and aluminium iron ore sinter phase formation, in Proceedings Iron Ore 2013 , pp 487-494 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By T Purvis, Z Liu

Ernest Henry mine (EHM) is an underground sublevel caving mine located in north-west Queensland with a production rate of 6.4 Mt/a. The mine has sublevels spaced with a 25 m vertical interval. The production process on each level starts with the drilling and firing of a blind uphole rise to start the slot extraction. These rises are fired as a single shot and routinely need to achieve a design height of 22 m to 30 m depending on the local mine geometry. If the rise fails to perform as designed then the production phase of the level is delayed with significant rework required to remedy the situation.This paper describes the process that the EHM team has followed to improve the first time performance of each rise. The improvement process commenced with a review of results from previous rises and resulted in the identification of a number of improvement opportunities. A revised holistic approach was established for the process, which included involvement from operators and engineers. Through continued measurement and review of rise performance, inputs to the process were improved to a point where reliable results can now be expected. The successful performance of subsequent rises has been verified through a comprehensive quality assurance quality control (QA/QC) program. Before quality control processes were implemented, the success rate of blind uphole rises was only 11 per cent (one out of nine rises) at EHM. In comparison, the success rates have been vastly improved to 25 per cent (one out of four) and 75 per cent (three out of four) respectively following two stages of improvements. This paper concludes with the ‘current’ series of best practices used at EHM and recommendations.CITATION:Purvis, T and Liu, Z, 2017. Improving the performance of blind uphole rises at Ernest Henry Mine – a case study, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 335–340 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By S Norman

The Water Delivery Alliance (WDA) was established to design, construct and commission the pump station and desalinated water delivery pipeline to link the desalination plant on the Kurnell Peninsula (constructed by others) with the existing distribution network at Erskineville, Sydney, Australia. The WDA consisted of McConnell Dowell Corporation Ltd (Macdow), Bovis Lend Lease Pty Ltd (BLL), Kellogg Brown and Root Pty Ltd (KBR), Worleyparsons Ltd (WOR), Environmental Resources Management Group Inc (ERM) and Sydney Water Corporation (SWC).Sydney’s Desalination Project is one of the initiatives to secure Sydney’s water supply against the effects of climate change, population growth and drought. The desalination plant, 100 per cent powered by renewable energy, can supply up to 250 million litres of water per day (mld), which is up to 15 per cent of Sydney’s water needs. The project involved the construction of an 18 km pipeline with an ultimate capacity of 500 mld to accommodate any future increase in the output of the desalination plant.The Alliance procured three full-face tunnel boring machines (TBM) from Herrenknecht AG to construct the 6.5 km of tunnel that would provide a conduit for the DN1800 welded mild steel cement mortar lined (MSCL) pipeline at a number of locations along the route. Nineteen shafts and 16 tunnels were required to complete this work.Crucially one of the TBM drives involved construction of a tunnel into Botany Bay under protected marine life habitats; enabling the connection of the MSCL water carrier pipeline into the dredged section of pipeline underwater, approximately 800 m off-shore in Botany Bay.This paper details the retrieval of the 17.4 m long TBM from the ocean floor upon completion of the Botany Bay tunnel allowing for subsequent use on the Project. Elements covered in the paper include the 835 m tunnel, design and construction techniques for the tunnel and recovery, and details of the methods used to install the DN1800 water carrier pipeline.

Mar 8, 2011

The Pongkor Gold Mine employs 678 staff. The mine is owned by the Indonesian state company PT Antam Tbk and is located 100 kilometres south west of Jakarta, in Java, Indonesia. Mine and infrastructure development started in 1992 following intensive geological exploration over 15 years. First gold production was in June 1994. The mine comprises three main orebodies: Ciguha, which is nearly mined out, dips at 75¦ from surface to 150 m. Kubang Cicau, dipping at 80¦ from surface to 230 m, and averages 3.5 metres thick at a grade of 10 g/t Au and 128 g/t Ag; and Ciurug, dipping at 60¦ from surface to 300 m and averages eight metres thick at a grade of 14 g/t Au and 172 g/t Ag. Present global ore reserves are 4.6 million tons at a grade of 12.3 g/t Au and 133.6 g/t Ag. Exploration is continuing for new veins. Initial mining was by manual cut and hydraulic fill at Ciguha, followed by Kubang Cicau. In 1996, it was proposed to convert Ciurug to a mechanised cut and fill operation. Two single boom jumbos and three load-haul-dumps (LHDs) were purchased with the assistance of a gold loan from NM Rothschild and Sons. Implementation of this upgrade was delayed by both a national economic crisis and an invasion of the concession by illegal miners. It was not until May 1999 that raise bore vent rises and access drift infrastructure commenced. Major underground development started in 2000 and is continuing. Production cut and waste fill stoping started in July 2001. The change from manual to mechanised methods has required a total change in work practices and attitudes. However, the process has resulted in a production increase from 600 tpd to 1200 tpd. A three-month compliance test (a condition of the financing loan) was successfully completed, from July to September 2001, with an average production of 700 tpd at Ciurug and 500 tpd from Kubang Cicau.

Jan 1, 2002

A nine-month investigation was conducted into the effect on coke quality and blast furnace operation of the addition of bentonite and southern coal to the northern coal fed to the coke ovens at the Newcastle steelworks.Additions of 0·3 per cent bentonite or 25 per cent southern coal to the northern coal increased the coke strength from 15-20 A.S.T.M. stability to 25-30 A.S.T.M. stability. It is likely that improved mixing and blending facilities would, in both cases, give a coke of over 30 A.S.T.M. stability.For the same coke strength, the use of 0 3 per cent imported Wyoming bentonite was considerably cheaper than the use of 25 per cent southern coal, but the use of Australian bentonite promises the same coke strength for still lower costs. Other additives such as coke breeze, charcoal, iron ore fines, and certain other finely divided materials, gave relatively minor improvements in coke quality.There appeared to be sufficient improvement in blast furnace operation and production to justify full scale addition of bentonite to improve coke quality, although other variables, particularly iron ore physical quality, overshadowed on many occasions the effect of coke quality. Further coke trials with southern or bentonite will be carried out when ore quality has been improved by the introduction of ore sintering at Newcastle.INTRODUCTIONDuring the period of operation of the Newcastle coke ovens and blast furnaces from April 1960 (when No. 3 blast furnace was blown in after rebuilding) to December 1960, a bentonite coke trial was carried out based on earlier research findings (Gregory, 1959a, 1959b; Felton and Gregory, 1960; Gregory, 1960) that as little as 0 3 per cent to 05 per cent bentonite clay added to northern N.S.W. high volatile coking coals gave a significant increase in coke strength. The bentonite coke trial was followed by trials...

Jan 1, 1962