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Control of construction projects is the responsibility of the Project Leaders who have the authority to make decisions. Project Controls cost and scheduling systems provide the Leaders with timely information on which to base their decisions.The Client (Owner) will invest up to three per cent of the project cost on Project Controls. To ensure that this investment is effective, the Owner or Manager must have a clear understanding of the information required from the Project controls systems. If appointing a single Managing Contractor, the Owner or Manager must stipulate what is and what is not required from the Project Controls Systems. There are numerous computer programs available for scheduling and cost control and it is important to select systems which best serve the Owner's needs.

Jan 1, 1993

Newcrest Mining Limited (NML) owns and manages the Ridgeway Gold Mine (RGM) located outside Orange in the state of New South Wales. RGM is a new underground sublevel caving (SLC) operation that is ramping up production to 4 Mtpa. The success of the SLC method at RGM is strongly influenced by production drill and blast practices. Distinguishing features of the Ridgeway SLC operation include choke blasting against broken rock, drawpoint brow preservation, loading of blastholes with different in-hole bulk emulsion densities, precharging of production rings and routine drawpoint fragmentation assessment. These areas are described in the context of RGMÆs required blasting objectives, production drilling and charging activities and innovative practices.

Jan 1, 2002

By C Garrido, J Barrera, H Alvarez, L Perez, S Ramirez

In recent years, there has had a greater recurrence of studies and projects that consider tailings filtration followed by dry stacking to reduce the consumption of fresh water, the space required for disposal, and, eventually, to reduce the costs of the project. In addition, this technique could be required to meet new environmental restrictions to extend the life-of-mine of existing plants or to enable the development of new projects, especially in areas of high social interest. This article is intended to describe the most relevant technical aspects of the design and implementation of an iron ore tailings filtering system and its final overland disposal as well as physical and metallurgical surveys, and laboratory and pilot testing. Furthermore, it is presented how these activities are inserted in the project development to rationalise the resources. The case under study considers an iron mineral wet magnetic concentration processing plant. The outcome tailings are dewatered by means of thickeners, where the overflow water is recycled back to the plant. The underflow slurry is pumped into intermediate storage tanks before proceeding with further dewatering and final disposal. The project consists of a tailings filtration plant, belt conveying systems, a temporary stockpiling system, trucking loading and transportation system, moisture-conditioning facilities (spreading and airing), and final disposal facilities (compacting). Due to the stickiness of the filtered tailings that governs the belt conveying system design, the operating moisture range must be established. Besides, proper technical aspects such as planning, executing, and analysing both the laboratory and the pilot testing data to validate process design parameters; selecting filters; defining spare filtering capacity; handling the out-of-range filtrated moisture; sizing the belt conveying system; configuring the equipment involved, must be considered.

Nov 8, 2021

Slide presentation at conference

Jan 1, 1996

By E C. F Hamman

Sunrise Dam Gold Mine is a large open pit mine 730 km NE of Perth, Western Australia. Contract mining commenced in the open pit in September 1996 in lake clays and saprolites with the first fresh rock mined late 1999, and the underground starting the first decline in October 2003. By May 2007, over 150 million cubic metres of material had been mined and the pit was 360 m deep with 80 m remaining before reaching the planned final depth in early 2008. A final cut-back in the northwest will commence in late 2007 with open pit mining in the Mega Pit expected to conclude in late 2010. The challenges of developing the pit can be divided into three phases:Soft materials û mining was in multiple staged pits and cut-backs in lake clays, saprolites, weathered material. The varying characteristics had a significant impact on mining methods and slope stability. Structural û mining was gradually exposing more fresh rock and the drive was to understand how major structures and lithological contacts impact on local and large-scale stability. This had a significant influence on mine design and scheduling. Slope angles û achieving the final slope angle is critical. This is done through application of high standards of final wall establishment and proactive geotechnical hazard identification and management. This includes dealing with the rapid rate of descent, interaction with underground excavations and managing rock fall risk. The paper discusses each of these phases, highlighting the geotechnical controls implemented to date, looking at their success and impact on mining.

Jan 1, 2007

By I T. Ross

In the last 50 years there have been tremendous improvements in equipment used in development on underground mines. Compressed air powered jacklegs have been replaced by high powered electro-hydraulic drifters on sophisticated drill jumbos and load haul dump units have taken over from small shovels and rail cars.Despite the increase in power applied in key parts of the development cycle, average advance rates have fallen and costs have increased. The factor that is most often regarded as the main contributor to slowing advance rates is increased support requirements. Whilst there is no denying that the drive to improve safety has resulted in the requirement for more bolting and the installation of a skin support (mesh or shotcrete), this is not the only factor.Within the industry as a whole, many of the basic principles of development appear to have been lost over time. This paper looks at a historical case study and discusses some of the features of old development cycles that are no longer in use. This highlights some of the basics that appear to have been forgotten. These may be indicators to what may provide improvements in the conventional drill and blast development cycle.CITATION:Ross, I T, 2014. Development – back to basics, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 67–74 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

To enable ammonium nitrate-fuel oil (AN-FO) to be used on an equal weight basis with nitroglycerine explosives, smaller diameter bore holes became necessary with consequent modifications to drill steel and burden on holes. Detonation of AN-FO in small diameter holes proved successful both with and without primer charges but some alterations were required to adapt anoloders to the smaller holes.Important factors in training all operators in the new charging method were the retention of improved fragmentation, avoidance of excessive overbreak and keeping wall rock dilution to an absolute minimum. The successful storage of ammonium nitrate in climatic conditions with daily temperature fluctuations above and below the critical 90°F has been achieved.INTRODUCTIONTechnical aspects of ammonium nitrate-fuel oil (AN-Fa) blasting agent are well covered in recent literature. This paper deals primarily with the manner of its introduction as the principal explosive underground at Great Boulder Gold Mines Ltd. and with the many problems encountered in the process. Following reasonably successful experimental firings in June 1962', using granular ammonium nitrate and an anoloder, permission was granted by theWestern Australian Mines Department to carry out test work in selected areas of the mine. The permit allowed for fuse firing only, and for a mixture of AN-Fa containing between 5t and 6 per cent fuel oil, with an adequate primer.The use of AN-Fa on an equal weight basis with nitroglycerine explosives, involved smaller diameter holes with alteration to ground burden and modification to drill steel.Initial tests indicated that it was apparent that AN-Fa could not replace gelignite on an equal weight basis if the...

Jan 1, 1965

By Weber W

Methods of calculation of the reliability of process computers are getting more and more important. The paper presents long period observations of 21 process computers with online applications in the iron and steel industry. About 5000 failure events during 10 years have been systematically recorded and evaluated. On the basis of these long time observations it is possible to develop a probability model of the failure behaviour of process computers.This failure model is constructed with four different states of the process computer:Working phase, working phase with undetected reasons, repair phase, failure phase resulting from external influences.The model is defined by differential equations for the probability of one of these four phases. Long time observations show, that all of these four phases are closely correlated with the capa-city of a process computer, restarting without detection of failure reason, changes of programs and software, costs and time of repair. So the result of this analysis is a model of failure for process computers, which allows to predict breakdowns of process computers on the basis of external parameters.

Jan 1, 1985

By K Blay, C McCamley, P Petrucci

The Newmont Boddington Gold (NBG) processing plant was designed for 35Mt/y with ball mills expected to deliver a combined new mill feed rate of 4837 tonnes/hr. Since beginning commercial production in late 2009, the plant has steadily increased throughput to meet design capacity in 2014 and reached 37 Mt/y in 2015. Through improved efficiencies, changes to the milling circuit have taken place since commissioning to take the plant beyond its design to an actual throughput of 39.0 Mt in 2017 and a budgeted throughput of 39.4 Mt/y this year.The NBG milling circuit has four parallel ball mills, each consisting of a 7.9 x 13.4 m ball mill with twin 7.5 MW fixed speed motors in closed circuit with twelve 650 mm cyclones. Each mill is fed by two wet screens with the undersize gravitating to a mill discharge hopper where it is combined with the ball mill discharge and pumped to hydrocyclones for classification. The cyclone underflow is re-ground to a target P80 of 150 µm.This paper will focus on process improvements made to the NBG milling circuit which include cyclone reconfiguration, fine screen panel redesign, implementation of an expert control system, mill power draw increase and grinding media changes to take NBG beyond its design throughput.CITATION:McCamley, C, Petrucci, P and Blay, K, 2018. Going beyond design at Newmont Boddington Gold, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 497–508 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By G Caddy, M Middleton, S Kerec, R Keil, J Tsalapatis

Arrium’s OneSteel Whyalla Steelworks in South Australia is a fully integrated plant which operates a single blast furnace. The key operational objective has been to maintain high process availability and stability while maximising the process efficiency and the produced hot metal quality. All ferrous raw material input feeds are sourced exclusively from company iron ore deposits in the nearby Middleback Ranges. The Whyalla blast furnace has mostly operated using a combination of a high percentage of pellet feed, produced in Whyalla, together with screened lump ore.The unique ironmaking challenge has always been to extract the maximum value from the ferrous burden feed available locally. In earlier times, high-grade hematite lump ore was available for both screened lump ore and pellet production. Blast furnace trials from acid to fluxed pellet feed commenced in 1977. The furnace pellet feed has been wholly fluxed since 1981. Many pellet/lump ore feed mixes and significant pellet chemistry composition design changes have been made over the years. These changes have been aimed at best balancing the ferrous burden availability/cost and the optimum reducibility/high temperature melting behaviour of the charged ferrous feed within the blast furnace. In more recent times since 2007, the Whyalla blast furnace operation has transitioned from a hematite based pellet feed to a magnetite based pellet feed while there is an ongoing contest dealing with diminishing absolute quality/increased variability raw material feed inputs.The paper will detail key elements of the Whyalla blast furnace operational philosophy with regards to ferrous feed use and process optimisation. The blast furnace ferrous feed design considerations will be discussed, together with the test work performed, the operational and slag design transition strategies employed and the process results achieved.CITATION:Tsalapatis, J, Middleton, M, Keil, R, Kerec, S and Caddy, G, 2015. The use and optimisation of ferrous feed at the Whyalla Blast Furnace, in Proceedings Iron Ore 2015, pp 377–384 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By T Schrimpf, I Bryan

The life cycle of a mining project begins with initial regional exploration and ends with mine closure and rehabilitation. Between resource definition and the commencement of mine construction is the study phase. In this phase technical concepts and processes are defined, evaluated and assessed with the aim of establishing whether the deposit is economically feasible. The study phase usually involves various steps from a concept/scoping study to prefeasibility and ultimately definitive feasibility study. The complete study phase can take several years. Although the costs for studies are low in comparison to actual construction and operating costs of a mining project, they are significant especially for junior exploration and mining companies advancing projects to the point of being funded.The studies aim to determine selected parameters for the project, eg mining and processing methods, operating strategy, etc and provide a roadmap for project development ahead. Although mining studies are of the utmost importance for the mining project and the project owner, they are usually carried out using a conventional engineering approach: the consultant or design engineer works to a defined scope of work. The resulting design might be based on good engineering, but might often also fail to provide the solution for the project owner that delivers the best shareholder value. An alternative to this more traditional approach to project evaluation is what we have termed a value engineering approach. Value engineering is a creative, organised effort, which in the case of a mining study analyses the requirements of the study for the purpose of achieving the essential outcomes with the highest shareholder value. The outcome of a study is a concept that delivers the highest achievable value of the resource project and shows the way ahead to realise this value. Through a group investigation by experienced, multi-disciplinary teams the value of the resource is improved through the study of alternative options, methods and processes. The scope of the study is not limited to a narrowly defined engineering scope, but to the creation of value.The study commences with the identification of key value drivers and risks, based on the available information (drill data, geotechnical data, metallurgical test work, etc). This enables the quantification of key uncertainties, risks and value adding opportunities. Study efforts concentrate on key value drivers and are not unnecessarily spent on side issues. This approach can significantly reduce the time frame and costs for the study phase.This paper describes in more detail RMDSTEMÆs value engineering approach to mining studies and illustrates it with examples and case studies.CITATION:Schrimpf, T and Bryan, I, 2012. The application of value engineering principles to mining studies, in Proceedings Project Evaluation 2012 , pp 163-170 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

Central to any business is its Asset Management Plan which encapsulates the business context and key organisational objectives such as profitability, safety and environmental standards. Life Cycle Planning (LCP) is a key component of an overall Asset Management Plan. A comprehensive approach to Life Cycle Planning forecasts the financial expenditure required to support the performance of the asset over the business life. It incorporates capital, maintenance and operational expenditure along with an estimation of economic life. Within its body the LCP provides the detail of the maintenance plan and method of its execution. Once optimised the LCP becomes the overarching plan executed through the application of several elements of the Asset Management Plan to ensure the return on investment from the assets is optimal. Each of the elements of the LCP is bound by a set of loops that provide information based on the analysis of outcomes. These loops drive the continuous improvement of performance and cost over the life of the asset. In this way we ensure that the LCP is a dynamic plan responsive to the changing business environment. The paper being presented today will describe the process undertaken and the outcomes derived when this approach was applied to a $600 M+ coal handling and preparation plant in QueenslandÆs Bowen Basin. It will also delve into the difficulties encountered from both technical and cultural aspects; the latter proving to be the most difficult to manage. It will describe the hurdles and barriers that hampered progress including the human influences and the natural desire to revert to what has been done in the past when things became a bit difficult. In the end the results are there to show that the upfront expenditure and investment in time was time and money well spent and the outcome has the operation well placed to manage the assets in a manner designed to deliver the optimal business outcome.

Jan 1, 2007

By C Hawtin, B Miller, D Ashton

Ernest Henry mine (EHM) is an Iron oxide copper-gold sublevel cave mine located 30 minutes north of Cloncurry in North-West Queensland. The underground mine lies beneath open pit excavations, which were in operation from 1999 to 2011. Fault structures carry large quantities of water from the cover sequence aquifer into the underground mine area. The open cut excavations exacerbates vulnerability of the underground mine to the high intensity wet season storms of northern Queensland. These factors combine to make hydrogeological issues high priority for mine operation. Water-related risks include the cost of removing water from the mine, flooding risk and mud rush potential.Turnover of key technical staff in late 2015 at EHM resulted in the mine being left in an untenable position of losing the primary source of technical knowledge. Due to encouragement of cross-disciplinary activity coupled with workload and resource sharing, the management team were confident in utilising on-site personnel to offset loss of experienced personnel.Remaining geology personnel took additional responsibility for hydrogeological monitoring equipment and planning of upcoming work. Consultant input was limited to review only and an emphasis was placed on knowledge transfer to the geology team. Using this strategy, a 13 hole dewatering program was successfully implemented, achieving a significant water level drop in areas of elevated hydrological risk, whilst also upgrading the hydrological monitoring sensor array.Through a development program centred on cross-disciplinary exposure, the technical team was able to retain key technical knowledge despite staff turnover and produce strong results outside traditional training and roles. This paper serves as a case study on the methods, strengths and drawbacks of putting a focus on cross-disciplinary exposure as a method to combat staff turnover.CITATION:Ashton, D, Miller, B and Hawtin, C, 2017. Go with the flow – managing hydrogeological staff turnover at Ernest Henry mine, in Proceedings Tenth International Mining Geology Conference 2017, pp 129–136 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By M G. Hawtin

The Rocklands copper project is a multilode, iron oxide copper gold (IOCG) + cobalt mineralised system located in the Eastern Fold Belt of the Mt Isa Inlier. Rocklands orebodies cover a range of oxidation zones from oxide, to supergene and primary. Each zone contains different economic minerals of interest. The supergene zones contain significant amounts of native copper and the primary zones are dominated by chalcopyrite. The juxtaposition of these oxidation zones and minerals make it an interesting mineralisation system.Current mine production sampling collects a nominal 3 kg drill chip sample from a 1 m composite, RC drilled interval. A site specific sampling procedure was needed to quantify introduced sampling error when taking grade control samples. Due to oxidation and mineralogical variation in ore zones we needed to develop a practically achievable sampling methodology that ensures minimum sample mass and sample error requirements are achieved to ensure ‘representative’ samples for all ore types.These issues are planned to be resolved using an experimentally derived method using principles from the Theory of Sampling. This method uses an experimental calibration of parameters K and a for Gy’s fundamental sampling error formula using a modified 32-piece sampling tree experiment to compile sampling nomograms for the primary and supergene ores. This paper demonstrates the process undertaken to improve the quality and standard of existing mine production sampling procedures at the Rocklands operation.Results indicate a sample mass of 5 kg for RC drill chips is appropriate for both the primary and supergene ores to achieve a fundamental error below 0.01 or 10 per cent relative error, which is slightly higher than the existing sampling protocol of 3 kg. An additional experiment is recommended to compile sampling nomograms using the exact laboratory comminution and mass reduction stage information to assess the use of a 3 kg sample. The results also indicate no changes are required to existing sampling protocols when sampling RC drill chips in primary and supergene ore at Rocklands.Sampling nomogram results also provide a useful ‘rule of thumb’ reference guide to other mining and exploration companies to help understand minimum sample mass requirements and sampling error during exploration drilling, resource evaluation and mining production stages when targeting similar IOCG mineralised systems. A sample mass of 5 kg is recommended when RC drilling similarly IOCG mineralised prospects and deposits in the Cloncurry area. Future test work is recommended when additional open cuts become active as well as including resource drilling drill core to provide better three-dimensional sample representivity.CITATION:Hawtin, M G, 2017. Minimum sample mass from reverse circulation grade control drilling at Rocklands copper project, in Proceedings Tenth International Mining Geology Conference 2017, pp 337–346 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By Baafi EY, Sun Y, Tague I

Field trials at three New South Wales and one Queensland coal mines were carried out to gather data on oxygen "run out" times of Self-Contained Self Rescuers (SCSRs), time taken to escape from the mine, distances travelled and the average heart rate of subjects wearing SCSRs. The study has led to a method of predicting the duration of oxygen supply from a SCSR as a function of the wearer's body weight, physical fitness and the prevailing environmental conditions. Escapeway design, planning for emergencies, familiarity with SCSRs and experiential escape training are critical to control panic and maximise the likelihood of survival of a person attempting to escape in an emergency involving fire or explosion.

Jan 1, 1998

Background BHP Iron Ore Pty Ltd is one of the major iron ore producers in the Pilbara Region of North Western Australia. The company manages three separate joint ventures; the Newman, Goldsworthy and Yandi joint ventures and two 100 per cent owned operations, Yampi and Jimblebar. The Newman operations constitute a mine site at Newman and a 426 km railroad to Port Hedland where there is an ore processing/port site. The Goldsworthy operations currently constitute a mine site at Shay Gap/Nimingarra, a developing mine site at Yarrie, a decommissioned mine site at Goldsworthy and an ore processing/port site at Finucane Island (Port Hedland). The Yandi operations include mining and processing facilities at site and a spur line to join the Newman Hedland railroad. Jimblebar operations are scree and bedrock mining near Newman and include mining, processing and a spur line to Newman where it joins the Newman-Hedland railroad. The Yampi operations constitute a mine/port site at Koolan Island (which is presently being decommissioned). The combined BHP Iron Ore operations produce approximately 46 Mtpa of iron ore. This paper will concentrate on the processes developed and applied for the decommissioning of the Goldsworthy site. The Goldsworthy site is on the northern boundary of the Pilbara Region and adjacent to the western extremity of the Great Sandy Desert. It is located approximately 110 km east of Port Hedland (see Figure 1). The area is generally of low relief with isolated low ranges. The mine site being within the Mount Goldsworthy range area. The geology of the area is essentially Archaean granite with Archaean banded iron formation becoming dominant within the ranges. The chief soils are hard alkaline red soils. The vegetation is essentially shrub steppe with the main hummock grass species being spinifex (Triodia sp). The climate for the region is semi arid tropical. The temperature ranges from a mean low of 15¦C in winter to a mean high of 40¦ in summer. Rainfall is episodic, occurring mainly throughout the summer as a result of tropical depressions or cyclonic activity. The average annual rainfall is approximately 300 mm and annual evaporation may exceed rainfall by up to 2500 mm. Goldsworthy Mining Ltd commissioned the Goldsworthy site in 1965/66. Goldsworthy was the first iron ore operation and associated town site in the Pilbara region. The mine development peaked in 1977 with the town population reaching 1400 people. In 1982 mining ceased and the mining operations were relocated to Shay Gap, 80 km east of Goldsworthy. The Goldsworthy town continued as the base for the railing operations between Finucane Island and Shay Gap. BHP Minerals acquired Goldsworthy Mining Limited in 1990. The population for the town of Goldsworthy at this stage was around 450 people. An assessment of the Goldsworthy site operations concluded that it was uneconomic to continue the operation of the site. The decision was made to transfer the base for railing operations to Port

Jan 1, 1994

The Hishikari gold deposit, discovered by the Metal Mining Agency of Japan, has become a giant class epithermal gold deposit with the highest grade of gold yet recorded in the world through detailed exploration and development by the Sumitomo Metal Mining Co., Ltd. The exploration strategy involved a regional approach combining geological and gravity surveys over a 900 km2 area which had historically produced over 120 t of gold. These surveys were carried out to grasp the common geologic features of epithermal gold deposits in the survey area. A genetic model for epithermal gold deposits in the area under regional survey was also considered based on detailed research of the Kushikino epithermal gold deposit which was in operation at that time. This model was applied to the targeted areas, and important relationships between mineralization, host lithology, intensive propylitic alteration and gravity highs became apparent. The Hishikari block was selected in this way and bonanza gold was discovered during drilling. Since the development of the Hishikari mine, information useful for further exploration for the same type of deposit has been accumulated.

Jan 1, 1995

By C McCracken, R Landers, B Hesse

Minnovare identified the potential to improve production drilling outcomes in underground long-hole stopes through the adaptation of new technology which was under ongoing development. An approach to Evolution Mining resulted in the companies agreeing to a collaborative agreement to further develop the technology for use on underground long-hole drilling equipment. During a period of six months in FY2018, a series of trials were conducted to compare drilling accuracy using two different methodologies and the subsequent impact this had on ore dilution. Testing was conducted at Cracow underground gold mine in Queensland, Australia. The drill rig’s existing setup/alignment process was compared to the new technology system with the following observations: • Using the existing process only 20% of holes surveyed recorded toe points within the +/ 300mm (11.8in) tolerance blast-hole deviation. • The new technology was proven to limit rig setup/alignment error, reducing average blasthole deviation and increasing the number of holes drilled within tolerance by 160%. The increased accuracy reduced stope dilution by reducing over-break of subgrade ore: • Stopes drilled using the new technology recorded 62.6% less average dilution. • This contributed to an overall reduction in dilution for the full year (FY18) of 5 percentage points compared to FY17 - from 22% to 17% (a net decrease of 22.7%). • With the system implemented as standard practice following results of the FY18 trial and continued success, overall dilution for full year FY19 showed continued reduction to 12% Evolution has continued use of the new technology at Cracow, where the improved accuracy has allowed the extraction of narrower stopes where drilling accuracy is critical. Evolution has also deployed the technology at the Mungari operation and has stipulated that the contractor use the technology at the Mt Carlton operation, which is currently under development. Future implementation of the Development Optimiser system should be verified by commencing additional trials to include a larger data base for validating the initial trial results.

Mar 15, 2021

The development and distribution of gold placers in Otago û Southland is related primarily to the evolution and architecture of three distinctly different drainage networks that developed during and since Gondwana breakup: +        Late-Gondwana û Pre-marine; +        Middle Tertiary Post-marine; and +        Modern. Late Gondwana û Pre-marine drainage was dominantly recti-linear and controlled by normal faults and sedimentary basins formed before or during Gondwana breakup. Placers formed dominantly in 2nd order transverse drainages with primary sources in their catchments. This drainage network was progressively destroyed by inundation and burial by marine strata during Late Cretaceous û Middle Tertiary marine transgression that ultimately covered most of New Zealand. Middle Tertiary Post-marine drainage evolved on and incised the newly emergent low-relief landscape during regional marine regression driven by development of the present plate boundary through South Island. Most of Central Otago was drained into Southland and to the southern coast via a large braided river system with an extensive network of tributaries in its Central Otago reach. East Otago was drained by several smaller systems. Placers formed dominantly in proximal and medial reaches of 1st and 2nd order drainages with primary or pre-existing placers in their catchments. This drainage network was destroyed by inundation and burial of the Central Otago reach of the major system by lacustrine strata following tectonic damning of its middle reach by range uplift and development of a lake complex that covered >5000km2 of Central Otago. The Modern drainage network evolved from the Middle Tertiary network through complex response, firstly to uplift of NW-trending and NE-trending ranges throughout the region since the Late Miocene, and secondly to the effects of major Pleistocene glacial advances in West Otago. Placers formed in alluvial fans at range margins, proximal and medial pre-glacial fluvial systems and glacial outwash sequences. Evolution of each of these drainage networks has been accompanied by widespread sedimentary recycling of alluvial gold from older to younger placers, augmented locally by input of first-cycle gold derived from erosion of primary sources in the repeatedly exhumed basement rocks.

Jan 1, 2006

By Y Durkheim, P Saunier, L Ameglio

"In the last decade Afitex developed the Draintube™ geocomposite, which provides simultaneous drainage and waterproofing functions. This new type of drain tubes planar geocomposites (DTPG) differs from other geocomposites as the drainage core is composed of multiple corrugated and perforated pipes instead of biaxial or triaxial nets. It is furthermore associated with needle-punch stitched layers of non-woven geotextiles, which act either as capillary mediums or as filters.In this paper, the structure of the Draintube™ drainage composite is presented along with its key properties and the drainage mechanism associated with its particular structure.The relevance of this kind of structure is then reviewed based on past and current laboratory bench evaluations and field installations for mining applications such as the covering of acid rock drainage (ARD) tailings for the Central Manitoba Mine (Canada) site-rehabilitation; and as a pregnant solution collection layer in heap leach pads.Some of the demonstrated critical advantages of Draintube™ in the mining industry are as follows: reduction of the thickness, hence lower volume of granular drain layers improvement of fluid and gas collection and reduction of the hydraulic load reduction of secondary collector network mechanical protection of the sealing membrane fast and economical installation of interlifts stability under extreme conditions (compression, temperature, pH) increased stability of entire covering system and reinforcement of protection of dykes filtration of the covered material customised drainage positive connection of the geocomposite to collector pipes enable leaks detection (using a conductive textile layer) with an electrical test.CITATION:Saunier, P, Ameglio, L and Durkheim, Y, 2015. Tubular drainage and lining geocomposite for mine tailings and heap leach pads, in Proceedings Tailings and Mine Waste Management for the 21st Century, pp 297–304 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 27, 2015