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By J Foo, T Kleinschmidt, B Reynolds, K Kennewell

The consideration of complex supply chains often highlights multiple system bottlenecks that are localised and dynamic – they shift depending on what variability last influenced the system. Using the understanding of a dynamic system model, synergies between items that tackle localised bottlenecks can be understood to generate a suite of solutions. These can be simple solutions, such as a couple of new conveyors placed in series, or more complex ones, including buffer dynamics (capacity, location, behaviour, etc).Each solution in the suite will have an associated uplift in system performance and an associated cost of implementation. Dynamic simulations can address each situation in turn and estimate the projected improvement it would offer. However, these solutions will have different benefits when implemented together, and each solution will give different uplift depending on what other solutions have already been assumed. If the number of solutions is numerous, traditional dynamic simulation analysis becomes the bottleneck, limiting options analysis to the processing power available.This paper will illustrate the use of a new technique applied as part of a capital growth optimisation project with a major iron ore producer. Metamodelling is the creation of a model of a model; in this case study, the focus is on developing a response surface representing the suite of solutions. This can be achieved through a combination of dynamic modelling and an appropriate mathematical process called design of experiments. The result is an approximation surface of the outcomes of the dynamic model, encapsulating interactions between key elements of the value chain.This modelling approach provides a number of advantages compared to traditional dynamic modelling approaches, including but not limited to:early and rapid evaluation of a large range of potential solutionsaccommodation of multiple initial states of the value chainoptimisation of the overall suite of upgrades (down to route-level upgrades) based on business objectiveseasy re-evaluation of outcomes when key inputs such as costs change.CITATION:Kleinschmidt, T, Foo, J, Reynolds, B and Kennewell, K, 2015. Case study of iron ore value chain optimisation, in Proceedings Iron Ore 2015, pp 605–612 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By B J. Hutchison, S Gannon, J Chambers, D Oko-oboh

The Kanmantoo copper mine is located in the Adelaide Hills area of South Australia and is owned and operated by Hillgrove Resources (HGO). The mine is a drill and blast, truck and shovel operation mining sulfide (chalcopyrite) ore located in chloritised andalusite biotite schist. The initial Kanmantoo open pit operation occurred in the 1970s, before falling copper prices closed the mine. In 2010 the mine was reopened by HGO and the Kavanagh cutback of the Kanmantoo pit was undertaken. The Spitfire, Nugent and Emily Star satellite pits were also mined through to 2015 before the latest steep wall Giant pit design was developed to take mining out to 2019.There are no major fault structures and only two significant shear zone structures exposed in the open pit walls. The main Garnet Andalusite Biotite Schist (GABS) unit is quite competent so the pit designs have therefore mainly been controlled by four distinct joint sets. This paper is a case study on the influence of the joint regime on the wall stability of the main GABS unit and how a better understanding of the joint regime and the use of rock reinforcement has allowed the steep wall design to be adopted.The paper also describes the remote geotechnical mapping and slope monitoring techniques used to manage the rockfall risks associated with the steep walled slope design.CITATION:Hutchison, B J, Chambers, J, Gannon, S and Oko-oboh, D, 2017. Case study of joint structure and the design and performance of open pit walls at the Kanmantoo copper mine, in Proceedings Tenth International Mining Geology Conference 2017, pp 355–364 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By R. J. Matetic

Mining operations have long been accused of causing a disruption to local, domestic and agricultural water supplies. More recently, concern for water supplies has increased with the advent of high-extraction mining techniques, namely longwall mining. Theoretically, any water bearing zone in the overburden above a high-extraction mining operation may be affected by mining. In some cases, a confining bed may be fractured causing a loss of water to a particular zone. In other cases, increased fracture permeability may enhance the ability of an aquifer to transmit and deliver water. Unfortunately, only a limited amount of studies have been conducted that characterize hydrologic changes and also quant1fythe magnitude of mining-induced subsidence. The U.S. Bureau of Mines conducted such a study at a mine site located in Greene County, PA. A total of 8 water wells were drilled and hydrologic parameters such as specific capacity, transmissivity and well yield were determined both before and after mining. Electronic water level recorders were installed on each water well to provide continuous observations of water level fluctuations.

Jan 1, 1990

By W M. Tekano, T S. Coulter, N M. Hutt

The Vancouver Island Highway Project (VIHP) was a $CAD 1.2 billion expenditure by the Province of British Columbia to improve travel safety and relieve traffic congestion between Victoria and Campbell River on Vancouver Island. In the section of highway between the Tsolum River and Oyster River, on the Inland Island Highway portion of the VIHP, over half of the rock to be cut and filled was found to be net acid generating. The Tsolum River has been impacted by metal leaching and acid rock drainage (ML/ARD) for decades from an upstream closed minesite. Geochemical testwork indicated: over half of the rock along this section of highway was potentially net acid generating based on a site-specific SNPR (=NP/SAP) criterion of 1.5; some core samples were already acidic; pyrite occurred in disseminated framboidal and gel forms; the rate of acid generation was not high; measured neutralisation potential (NP) provided some lag time for the onset of net acidity; and non-carbonate neutralising minerals prevented low pH (These predictions led to ML/ARD controls involving: realignment of the highway; elevation control to minimise the volume of disturbed rock; encapsulation of blasted-rock fills within the highway, surrounded by low-permeability till and covered with asphalt; and diversion of water away from cut faces. Internal pipes drained any water reaching the fills into external ditches and ponds, where the water could be monitored and, if necessary, treated. Water from the cuts was also captured in ditches and carried to monitored ponds. Elevated aqueous sulfate concentrations in several ponds confirmed that sulfide minerals were oxidising, but the lack of both acidic pH and increasing trends in concentrations demonstrated that ML/ARD was controlled. Contingency plans for any pond that may become acidic include water treatment, which predictive testwork has shown would not require substantial amounts of limestone or lime.

Jan 1, 2003

By Jérôme Girard, Shiu Kam, Sue Longo

"Historically, tailings management in a northern climate has involved the deposition of tailings into the Tailings Management Area (TMA) as conventional slurry. This type of system is obviously viable but presents challenges that are difficult to manage as circumstances change over the life of mine. These issues can include:? Increases in mill throughput, and? Life of the TMA for the life of mine.This case study will present how thickened, high-density, non-segregating tailings are used as an alternative to conventional slurry disposal to achieve greater storage capacity and enhanced environmental performance for a gold tailings facility in a northern climate. This paper will focus on how this change in deposition strategy accommodated the increased throughput of the mill and the increased life of mine. Specifically, the paper will discuss the addition and integration of new processes to the exiting mill system to accommodate the tailings management issues. It will highlight the challenges from laboratory testing to pre-feasibility to the engineered design of the thickened tailings system implemented at Musselwhite Mine.BACKGROUNDGoldcorp Canada’s Musselwhite Mine, in Northwestern Ontario (120 km north of Pickle Lake), is an underground gold mining operation that began production in 1997. The current mill throughput is about 4000 tpd (1.4 Mtpa). Gold extraction is based on a CIP process with cyanide destruction.The existing tailings management area (TMA) is located about 2 km southwest of the mill complex. The TMA is contained by high ground to the north and to the west and flanged by a moraine ridge along the south side. A number of dams have been constructed along this ridge. The dams were first built in 1996 and subsequently raised in 2000 and again in 2005. Excess tailings pond water is discharged to a polishing pond then released to the environment via a wetland.The TMA was originally designed to contain 13.7 Mt of tailings under a ponded surface for closure. The water cover was to inhibit adverse long-term environmental effects because the tailings contain pyrrhotite and other sulphide-bearing minerals that are potentially acid generating. The design was modified during Stage 3 Construction in 2005 to expand the storage capacity to 17.3 Mt (Golder, 2005). As of end of 2009, over 16 Mt of tailings had been deposited in the TMA. The slurried tailings were historically deposited at 50% solids."

Jan 1, 2011

By Chris A. Bennett, Glenn S. Dobby, David A. Bulled

Establishing reagent dosing strategies for new ore bodies has traditionally involved a combination of experience and empirical experimentation using standard laboratory tests. The grade and recovery data resulting from these lab tests have historically been used as direct indicators of plant performance despite the obvious differences between the flotation environments. A reagent scheme selected in this way would subsequently be employed to generate the grade and recovery information for the geometallurgical model which in turn was used for metal production and cash flow forecasts. If the reagent scheme was sub-optimal then so too would be the forecasts and the resulting cash flow.

Jan 1, 2003

By John Newby, Mahmood Khwaja, Bernard Theron, Janice McGovern, Bernard Catalano, Michael S. Schultz

Launching a full-size pressurized-face Tunnel Boring Machine (TBM) in difficult ground conditions is always challenging. Recently, few projects have innovated the process by scaling the trenchless method of pipe jacking, and modified steel bell approach, to facilitate the launching of a full-size TBM without the need for large and deep trenches, starter/tail tunnels, or for incrementally installing supporting gear as the machine advances. This paper presents three such projects; evaluates the post-bid contractor proposed modifications; details the innovative use of pre-cast pipe segments to facilitate machine launch; and, provides an overall assessment of the benefits, challenges and lessons learned related to the modified approach.

Jun 13, 2021

By G. R. Lane

A large opencast gold mining company in Africa had just completed a feasibility study for the expansion of the operations. A traditional net present value project valuation methodology had been used that showed a very positive net present value (NPV). The project team had conducted a qualitative risk assessment that identified and logged all potential project risks and had subjectively incorporated ?risk? via the discount rate and other assumption contingencies around gold price expectations, operating parameters etc. Management requested that an independent quantitative risk modelling approach be adopted to obtain a better understanding of the impact of risk on the overall project valuation and confidence level in the final valuation. A detailed project valuation model was configured in the Carbon Modelling Technology and the stochastic modelling module used to perform the Monte Carlo simulations. Analysis of historical operational performance data relating to actual achievements versus planned and budget determined the historical variability of the underlying parameters as well as variance to budget. This was done at a detailed level for mining rates and costs, processing rate, costs and recovery, and other operational efficiency measures. External market assumptions relating to gold price, exchange rate, and inflation were modelled and the dependency between them modelled using a copula. This case study will demonstrate the approach taken to building and populating the quantitative risk model and the overall results of the Monte Carlo simulation. The final valuation demonstrated that the project had a 44 percent probability of an NPV less than zero i.e. 44 percent chance of project finance loss.

Jan 1, 2012

By Stanko Nikolic

The Top Submerged Lance (TSL) technology, developed in the 1970s, is now widely used for the processing of a range of materials. TSL technology for continuous converting was first patented in the 1990s. The process is based on the use of calcium ferrite slag. Although this slag system had been applied elsewhere the phase equilibria had not been thoroughly investigated. This lead to a collaboration between the Process Technology group of Mount Isa Mines, now part of Glencore, and the Pyrometallurgy Innovation Centre (PYROSEARCH) at The University of Queensland. Through multiple research programs this complex system was successfully investigated. The results were then implemented within thermodynamic modelling tools. This combined new knowledge was then applied to the design and industrial implementation of the TSL continuous converting technology, ISACONVERT™. This paper describes the key findings of the research and how this was applied to the industrial implementation of the technology.

By Stuart Brashear, Steven Bell, Donald Smith

This Limestone site required the removal of a bench containing high quality rock located in close proximity to sump and pit pump. The sump and associated electrical box were below the bench that needed to be blasted and located only 70 feet (21.33 meters) away. It was proposed to blast material needed without moving or disturbing the pump or electrical junction box. The area to be blasted was flown with a drone and stitched into a 3D orthographic model. Proprietary blast design software was used to create a blast design solution that would allow for a series of blasts that would provide required fragmentation and muckpile development and not disturb the sump or electrical box. A drill patten was created for each blast using the burden heat map and 3D face profiles created from the 3D orthographic model. Timing contour lines and muckpile displacement predictions were used to create timing sequences for proper face movement away from the sump and electrical box. The shot designs were laid out with a GPS system to insure hole location accuracy. All holes were remeasured for proper face burdens using the 3D model and Boretrak®® data collected after drilling operations were completed to insure hole locations were within face burden tolerances as derived by the burden heat map. After each drill log was reviewed, a charge loading scenario was created for each hole. The timing design created, for each shot and was reviewed and adjusted as needed with regard to desired muckpile displacement away from the sump and electrical box. Blasting results were satisfactory, with fragmentation and muckpile development consistent with the calculated throw from the blast model, with no rock hitting the pump or box and no rocks striking the sump water and disturbing the pump motor.

Jan 21, 2025

By A. B. Seal, C. J. Bise

Excessive noise has long been a hazard in the coal-mining industry. Studies conducted during the mid-1970s and mid-1990s consistently show that hearing loss within the mining industry persists, in spite of regulatory requirements and sampling technology advances. When the U.S. Mine Safety and Health Administration's new health standards to protect miners from hearing loss took effect in September 2000, the potential developed to reevaluate sampling approaches with regard to noise-source hazards, such as task-based methods. This paper describes results from a Pennsylvania State University research project now being conducted at an underground coal mine. Each occupation was reviewed, and a list of tasks or processes performed by each was generated. Traditional personal noise dosimetry, static sound pressure levels and equipment sound mappings have been performed. Job tasks indicating the greatest levels of daily noise exposure and contributions to noise dose have been identified and will be discussed.

Jan 1, 2003

By N Currey, G W. Wilson, P Ritchie

Kidston Gold Mine in Queensland, Australia has a 310 ha tailings impoundment that has undergone final closure rehabilitation. Kidston Gold Mine evaluated their closure options for this low acid generating tailings impoundment, and due to a lack of cover soils and the cost of importing material, the mine decided to investigate the possibility of direct vegetation onto the tailings impoundment surface. The mine subsequently embarked upon a well planned and detailed research program to determine the feasibility and sustainability of this closure option. The research program included vegetation trials, toxicology studies for metal uptake by vegetation, as well as a comprehensive closure water balance model for the tailings impoundment complex. This paper describes the results of the long-term closure water balance for the tailings impoundment complex for the pre-closure state of the impoundment, as well as predictions towards the impoundment performance once final rehabilitation of the tailings impoundment complex has been achieved. The water balance presented is unique in that it is founded on unsaturated flow principles and accounts in full the impacts of the surface flux boundary conditions. This novel approach enables the prediction of actual infiltration rates into the tailings impoundment surface, which in turn allows for the calculation of how much seepage will exit from the tailings dam toe drains.

Jan 1, 2003

By M J. Shearer

An investigation into the reliability of the data being collected at the Mount Isa Mines site operated by Glencore in Queensland allowed on-site ventilation personnel to scrutinise pressure and volume measurements collected from the primary surface fans. The investigation effectively identified discrepancies being reported to the on-site remote monitoring system. The difference between the real-time and static measurements on the P63 RAR shaft identified that the in situ differential pressure transducer and piezo annubar system was not operating correctly. This indicated a deficiency of approximately 30 per cent reporting back to the remote monitoring software versus the live readings measured with the Pitot tube bomb and ALNOR AXD610 pressure micro-manometer.Constant monitoring of an operations ventilation network is imperative to ensuring that the underground atmosphere provides a safe and healthy workplace. Further benefits to real-time monitoring allows for the early indication of network failures and promotes increased availability. An innovative approach to out engineer and improve the existing measuring equipment from the 1970s was sought.The use of ultrasonics in the mining industry is not new with ventilation management systems (VMS) equipment available within the marketplace. The introduction and implementation of a reliable product for real-time monitoring was a challenge to overcome due to limited access and suitable measuring points within the mine. The available equipment on the market through mainstream suppliers was not suitable for the unique application required due to the in situ installation of the surface fans. A solution was identified in the oil and gas industry through collaboration and innovative thinking. This paper describes the sustainable approach to implement a reliable air flow monitoring system on-site.CITATION:Shearer, M J, 2017. Case study – an analysis of reliability and efficiency: ultrasonic versus annubar technologies, in Proceedings Australian Mine Vent Conference 2017, pp 51–56 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By J Harris, J Turner, P Kirsch

Coal mining is recognised globally as a hazardous activity, and as a result operates under high levels of regulatory and public scrutiny while managing a workforce operating in a high-risk environment. Mining companies have developed sophisticated risk assessment procedures, management systems and personnel competency requirements that facilitate the safety and health of employees, and Australia is a world leader in coal mining safety and health.RISKGATE is an Australian Coal Association Research Program funded online platform that delivers broad cross-industry knowledge about current practice in the identification, assessment and management of coal mining risk. Centennial Coal has engaged with the RISKGATE program, managed by the University of Queensland’s Minerals Industry Safety and Health Centre, since its inception in 2010, and contributed topic experts to many modules, including underground topics within the geological and geotechnical domain (strata underground, outburst, coal bumps and bursts, and inrush).In 2013, Centennial Coal experienced significant unexpected strata failure at the Mandalong mine without any personal injury or fatality. This paper presents a case study in the application of RISKGATE to management of this unwanted event, the steps that were implemented, the information that was sourced and the contribution that RISKGATE made to the final outcomes. The Australian coal industry is encouraged to embrace our knowledge platform, and to also openly share processes and practical outcomes that result from integration of RISKGATE in mining operations.CITATION:Harris, J, Turner, J and Kirsch, P, 2014. Case study – application of RISKGATE to managing strata failure in an Australian coalmine, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 55–60 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By Patrick Rennkamp, Wolf-Dieter Trodel, Andy Fearn

"The Jansen shafts are completed using purely mechanical excavation. This paper summarises the geology, a description of the shafts, the method used for excavation and the results achieved along with the challenges encountered and the solutions developed during the project. This experience is now being applied in the next generation machines and shaft sinking processes. This pioneering approach is changing shaft sinking in soft and medium to hard rock. INTRODUCTION The Jansen Mining project located approximately 150 km east of the city Saskatoon is the location of the BHP owned potash mine with an expected mining output of eight million tonnes annually upon completion. Mining contractors DMC Mining Services have used two Herrenknecht Shaft Boring Roadheaders (SBRs) to excavate the two blind shafts with an approximate excavation diameter of ten metres (inner diameter approximately 8.3 m) to depths of -975 and -1005 metres, respectively. The SBRs excavate the rock by a partial-face cutting method, using a transverse cutting drum mounted on a telescopic boom. The excavated rock is then conveyed away from the bench by an innovative pneumatic system and transferred into muck buckets to be hoisted to the surface. No drilling and blasting was done to keep to the BHP philosophy of using only mechanical excavation for this reference project. BHP VISION – MECHANICAL EXCAVATION BHP focused on mechanical excavation at Jansen due to the following perceived benefits: 1.No workers in the excavation chamber (shaft bottom), minimizing the exposure to traditional shaftsinking hazards associated with working in the shaft bottom. 2. Minimal damage to the rock fabric reducing the need for ground support and avoiding potential impact damage to freeze tubes located around the shaft. 3. Accurate excavation diameters with no overbreak, reducing volumes of rock to be removed and replaced with concrete lining."

Jan 1, 2019

By G du Toit, P L. Gillot, M Swanepoel

Randgold Resources’ Loulo-Gounkoto Complex is one of the largest gold mining operations in Mali, West Africa. The mine, which is situated on the western border with Senegal, treats more than 4 Mt/a of ore through a conventional three-stage crushing and ball milling circuit followed by a carbon-in-leach plant. Ore supply is achieved by a combination of open pit and underground mining, with the majority of the ore supply sourced from the Gara and Yalea underground mines situated approximately 2 km and 6 km respectively from the gold plant.In 2011, Randgold Resources commissioned Golder Associates to perform an evaluation study for providing structural backfill to both the Gara and Yalea underground mines using the current gold plant tailings. The test work performed as part of the evaluation study concluded the need for a tailings cycloning and dewatering facility capable of producing slurry at a solids concentration of 65 per cent with a particle size distribution that had minimum 25 per cent passing 20 µm and less than 5 per cent of -5 µm material. Tailings desliming was required to ensure a consistent feed quality to the paste preparation plants and to ensure that the system would be capable of handling variation in the feed composition from the gold plant.WorleyParsons, previously TWP Projects, was contracted by Randgold Resources to complete the engineering design for the slurry preparation plant, whilst Golder Associates was retained to complete the engineering design of the two paste preparation plants.This paper discusses the test work, design considerations and engineering design of the slurry preparation plant, termed the ‘intermediate plant’, as well as all ancillary facilities required for the delivery of the deslimed slurry to the paste preparation plants located at the two underground mines.CITATION:Swanepoel, M, du Toit, G and Gillot, P L, 2014. Case study – engineering design for a slurry preparation plant for a paste application in West Africa, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 477–486 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By P Nichols, C te Kloot, A Harrison

Ernest Henry mine (EHM) is a sub-level caving operation located in north-west Queensland, Australia. Located below a previously mined open pit, the underground operation ramped up production to 6.8Mt/a in 2017. The EHM ore body dips at 45 degrees to the South and therefore requires each level to “step out” from the level above as seen in Figure 1. Within this step out zone it is important to both maximise recovery and allow for efficient operation of the underground workings production to bring the level up to full production as quickly as possible. Throughout the step out design process, a combination of further defining the ore boundary, using lessons learnt from production performance on upper levels and the introduction of design improvements, has reduced the production ramp-up time, decreased costs and increased recovery for a single level at EHM. CITATION: Nichols, P, te Kloot, C and Harrison, A, 2018. Case study – Ernest Henry Mine: designing step out zones in an inclined sub-level cave, in Proceedings Complex Orebodies Conference 2018, pp 53–54 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By A. Rai

"This paper provides an overview of the current use of auxiliary ventilation product and the challenges with limited air quantity in dead-end entry or working face. The PVC low frictional factor, low physical constraint and minimum leakage ventilation duct was development with ""made in US and used in US"". The PVC duct development covering operational and total cost of ownership with on-going success will be presented. This paper will discuss mine sites using new PVC vent duct underground and the results from operational and technical side making a difference. INTRODUCTION The Turquoise Ridge Joint Venture (TRJV) is located in northern central Nevada, and is situated within the Basin and Range province, near the northeast end of the Osgood Mountains (see Figure 1). The TRJV mine consists of typical Carlin type- gold mineralization characterized by low strength rock of altered limestone’s, siltstones, and mudstones. The weak nature of the ground facilitates the underhand cut and fill mining methods [3].Mining Method; Underhand cut and fill : The mine uses underhand cut and fill method which has 12’x12’ top cuts and several different size undercuts. The ore body is accessed off of a secondary development heading, utilizing a heading with a cross section of 14W x 14H or 15W x 16H configuration. In the wider and more massive zones, two headings in a production panel may be worked at any one time. Drift round lengths are determined by the type of drilling machine being used. An example of a typical topcut and associated undercut layout is shown in Figure 2. SECONDARY / AUXILIARY VENTILATION IN UNUNDERGROUND METAL MINES The auxiliary ventilation system provides the required air volumes at the face of dead-end developments and production workings, which in many cases may be considered as the primary method of assuring that the air quantity and quality standards in these working areas are satisfied. The Auxiliary fans and ducting systems are usually the primary means of delivering the required air volumes to the face of dead-end developments and production workings. Both centrifugal and axial-flow fans are used in underground auxiliary ventilation systems, usually electric powered. The internally direct driven axial-flow fans tend to be more popular because of their compactness and adaptability to staging. The most commonly used materials for ridged tubing are coated steel, alloyed steel, fiberglass and resin. Flexible (collapsible) ventilation tubing is also used and is usually made from neoprene-coated or nylon material. To add stiffness and reduce collapsibility these fabric ducts can be formed over a steel spring frame. A very important factor in the design of an auxiliary ventilation system is to minimize leakage and reduce the frictional pressure losses along the auxiliary ducting systems by minimizing their friction factors (K)."

Jan 1, 2015

By T. Weatherwax, A. Rai, J. Poor

"This paper provides an overview of the current use of auxiliary ventilation products and the challenges with limited air quantity in dead-end entry or working faces. The PVC’s low frictional factor, low physical constraint and minimum leakage properties were ideal to develop as ventilation duct in conjunction with the concept of ""Made in the US and Used in the US"". The PVC duct supports the operational and total cost of ownership with on-going success. This paper will discuss the continuous improvement made in ventilation ancillary products for optimum results. The paper will also cover mine site usage of second generation PVC vent duct underground and the results from the operational and technical side making a difference in health and safety and overall auxiliary ventilation. INTRODUCTION The Barrick Turquoise Ridge Inc. (TR) is located in northern central Nevada, and is situated within the Basin and Range province, near the northeast end of the Osgood Mountains (see Figure 1). The TRJV mine consists of typical Carlin type- gold mineralization characterized by low strength rock of altered limestone, siltstones, and mudstones. The weak nature of the ground facilitates the need for underhand cut and fills mining methods.Mining Method; Underhand cut and fill: The mine uses underhand cut and fill method which has 12’x12’ and or 14’x14’ top cuts with several different size undercuts. The ore body is accessed off of a secondary tertiary heading, utilizing a heading with a cross section of 14W x 14H or 15W x 15H configuration. In the wider and more massive zones, two headings in a production panel may be worked at any one time. Drift round lengths are determined by the ground conditions and drift dimension. An example of a typical topcut and associated undercut layout is shown in Figure 2."

Jan 1, 2016

By K. Huttu, A. van Wageningen

"The Kittila underground mine is extracting one of the largest known gold deposits in Europe and has an estimated mine life through 2034. The Kittila mine is located in the Lapland region of northern Finland, approximately 900 kilometres north of Helsinki and 150 kilometres north of the Arctic Circle. The ore at the Kittila mine is refractory, making gold extraction relatively difficult because the gold is generally locked inside the two main sulphide minerals – arsenopyrite and arsenic-rich pyrite. The orebody consists of a complex pinch-and-swell structure including up to 100 different gold mineralization lenses. Fluctuating gold prices and other economic considerations increase the need to maintain and update the mining plans more frequently. Over 3,000 stopes need to be designed and optimized once a year for the LOM-plan and more frequent updates are needed for mid- and short term plans as well as production studies. As a large part of ore body is very sensitive to cost and gold price changes, stope optimization is crucial to find the best possible production scenario for every moment. Kittilä has gone through several methods for stope design and optimization. Most recently the Deswik Stope Optimizer (Deswik.SO) has been successfully used. Dewsik.SO has helped Kittilä to design and optimize stopes in a timely and cost efficient manner. Together with the Deswik suite of planning tools, reliable and auditable plans are created. This paper describes the methods used for stope design and optimization at Kittilä. THE KITTILÄ MINE The Kittila underground mine in northern Finland is extracting one of the largest known gold deposits in Europe. Kittila achieved commercial production on May 1, 2009, becoming Agnico Eagle’s first mine to open outside of Canada. The Kittilä orebodies were initially mined from two open pits – Suuri and Roura – and underground operations were added in October 2010. The pits were mined out in November 2012, so mining is now entirely underground in the Suuri and Roura deposits. Additional, small open pits will mine any remaining near-surface reserves in the future. The Kittila mine is located in the Lapland region of northern Finland, approximately 900 kilometres north of Helsinki and 150 kilometres north of the Arctic Circle. With a mine life estimated through 2034, Kittila is Agnico’s longest-life mine. The mine’s proven and probable reserves contain 4.7 million ounces (32 million tonnes at 4.6 g/t gold). Ore has been mined from underground since 2010. The original 3,000-tonne-per-day operation underwent an expansion project to increase the throughput capacity of the mill by 1,000 tonnes/day, starting by the end of 2014. The region around the Kittila mine is underlain by mafic volcanic and sedimentary rocks of the Kittila Greenstone Belt oriented nearly vertical. This greenstone belt is similar to those hosting Agnico Eagle's Canadian deposits in Quebec’s Abitibi region and Nunavut. At the contact point between iron-rich and magnesium-rich rocks lies a 100- to 200-metre-thick structural zone known as the “Suurikuusikko Trend”. This trend hosts the Kittila deposit, where multiple mineralized zones have been traced over a strike length of more than 25 kilometres."

Jan 1, 2015