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In any strip coal mining operation the aosL important single operating unit is the dragline. Because the capital and operating costs of a dragline are high, it is desirable to operate these machines at their maximum efficiency. Thiess Bros. Pty. Limited operate a Bucyrus-Erie 1350 Walking dragline at their Callide coal mine. The operating conditions at the Callide Mine are different from those of other coal mines situated in Central Queens ,nd. The topography is rugged, the coal seam is thick, and the overburden is hard and inter- HH,inded. Several different operating techniques for a large dragline working under these con- ditinns arc discrossmd it tt

Jan 1, 1978

The current economic climate and demand for iron ore has resulted in mine operators being prepared to accept aggressive slope designs and associated failures provided that they can be quantified (ie volume of failure and clean up costs, etc) and incorporated into the mining costs, at a feasibility study level. This has numerous implications for pit slope design/geomechanics. Typically when geotechnical engineers conduct slope stability modelling a single value, usually the average or mean value for model input parameters (ie structural orientations, material properties and hydrological conditions) are chosen. The implications resulting from using a single value for model input parameters will vary depending on how the modeller has chosen the value, ie should the modeller choose a mean value from a log-normal distribution of material strengths an optimistic representation of the stability may eventuate, consequently if the designer decides to conservatively downgrade the values by a nominal factor, a pessimistic representation of slope angles may occur, which would result in excessive stripping and mine development costs. A more realistic and representative way to model the inherent variability of geological/geotechnical conditions would be to do so probabilistically. Whereby the modeller can assess the variability of the geological structure as observed/recorded during the core logging process and a similar approach for the material strength properties. The final model output would be a distribution of factors of safety in relation to overall slope angles, ie probabilities of failure for individual slope angles could be determined. This output (graph) could be modified by the mining engineer to incorporate mining costs as well as clean up costs for the respective slope angles and associated failure volumes, ie probabilities of failure. The author intends to provide a detailed overview of the processes involved in deriving a geotechnical design, ie; starting from the data collection phase (core logging/face mapping), through to the data interpretation and formulation of slope parameters; determining the variability and uncertainties associated with each of the process; ensuring that it is adequately captured in the model input parameters; and how the mining engineer could utilise this information to derive final feasibility study mining costs.

Jan 1, 2009

By A Hughes, S G. Rosin

This paper presents the design and construction approach adopted for the widening and stabilisation of the existing decline tunnel forming part of the Scenic Railway Upgrade project at Katoomba in the Blue Mountains of New South Wales (NSW), Australia. The overall upgrade project included new trains and track, rebuilding of the top and bottom station and installation of a new winch and control system. All the works were undertaken over an eight-month period between August 2012 and April 2013 as part of a $30 M upgrade of the railway.The railway is the steepest cable-driven line in the world at a maximum of 52° extending over 350 m and descending from the escarpment into the Jamison Valley. The track was built in the 1880s for coal haulage and is recognised as a remarkable engineering achievement for its time. The tunnel section extends for about 120 m at the start of the decline and is about 3.5 m wide and 3.5 m high. The tunnel was excavated principally within medium to high strength Banks Wall sandstone and given that the widening only involved about 200 mm of trimming of the crown and sidewall this aspect of the work was not a critical support issue, except at the upslope portal. The tunnel crown however is entirely intersected by a major near vertical shear zone which presented significant challenges for the tunnel stabilisation works.Three-dimensional laser survey scanning was used for definition of the tunnel clearance envelope for the widening, and also to subdivide the tunnel into various geotechnical sections to assist in support design. Specifically oriented rock bolts extending beyond the shear zone into stable rock were used together with mesh, shotcrete and extensive strip drains and flushing points for drainage of the shear zone.Unique aspects of this project were included into the specifications and work methods. This included construction of a mobile working platform for tunnel works, the use of dry shotcrete application, difficult access for rock bolting and limiting vibration during the tunnel trimming works due to the risks associated with crown instability. The works also took into consideration particular safety constraints/work exclusion areas to address the risk of detachment of rock which could mobilise downslope to the track area below. This was required because other works were in progress such as micro-piling and bottom platform works which were being undertaken concurrently with the tunnel work.CITATION:Rosin, S G and Hughes, A, 2014. Scenic Railway Tunnel upgrade in the Blue Mountains, New South Wales – an approach to design and construction, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 607–618 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By P J. Handley

"Predicting how coal seams will be beneficiated through the coal handling processing plant (CHPP) has long been challenging within BHP Coal. Various coal seams from different areas are mined and stockpiled separately, often depending upon a deleterious coal quality parameter; high/low trace elements for example. These stockpiles are then fed in different ratios into the CHPP to produce the desired product/s. In understanding the washability characteristics of the feed source, mine geologists and process engineers work together to improve the beneficiation of different coal materials through the CHPP.For the majority of the BHP Coal deposits, the washability data is available for the coal seams across the deposits. However, no previous standardised modelling and prediction technique existed that could ensure the correct information was available for forecasting and refining CHPP processes. This paper will discuss the steps undertaken to implement a geometallurgical prediction tool that simplified and streamlined the washability modelling and yield estimation process. The value realised to the BHP Coal assets resulting from this process was: improved compliance to plan increased throughput increased CHPP recovery through improved efficiencies and increased revenues.CITATION:Handley, P J, 2017. Washability modelling and estimation techniques used to improve coal handling preparation plant beneficiation, in Proceedings Tenth International Mining Geology Conference 2017, pp 327–336 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 20, 2017

By H Lemos, E Nunes, D Jacobson, R Costa, L Ono, A Alves, H Delboni Jr

Oversize rock breaking and metal tramp removal are key issues for reducing primary crusher downtime, as well as improving the safety associated with its operation. Remote operation of such tasks would thus not only increase productivity, but also reduce the risks related to work in confined spaces, fall risks, and overhead hazards. These issues are particularly relevant in high-capacity operations such as iron ore mining, where large machines are in continuous operation. This article describes the architecture, construction and advanced testing of a novel remotely operated robotic mechanism for assessment and removal of metal tramp from primary crusher chambers. The system essentially includes a robotic-arm equipped with a hydraulic clamp tool for handling oversize material, as well as an oxy-flame module for cutting metal pieces entrapped within the primary crusher cavity. The first industrial unit was delivered to a large iron ore mine in Brazil, where the installation and testing is scheduled within the coming months.

Nov 8, 2021

Mining epitomises the challenge of sustainable development, because few sectors have such a direct impact on the natural environment, yet few are more important to the economic and social health of almost every region in the globe. In a global industry, with increasing competition for exploration and mining investment dollars, sustainable development must also be resolved within an international competitiveness framework. In formulating a response to the challenge of sustainable development, the State and Federal Governments do not fully appreciate the extent to which technology drives the solution on a range of issues. In some cases` a dangerous fatalism about the state of science has led to an unhealthy æstop productionÆ attitude that puts our industry and economy at risk. As a technical institute representing the professionals in the minerals sector, The Australasian Institute of Mining and Metallurgy (The AusIMM) sees one of its roles as being to highlight the way in which industry innovation can facilitate solutions. The AusIMM is currently evolving a greenhouse gas emissions policy. As a case study it throws into sharp relief the way in which irresponsible ælimits to growthÆ policies could have a negative impact on the sustainability of the sector, as well as the importance of a technology- based solution. With 80 per cent of greenhouse gas emissions in the next twenty years projected to come from developing economies, such as India and China, major reductions will only be achieved if cost-effective, low emissions energy technologies are deployed in developing countries, and more energy efficient processes of producing key commodities for them are brought online. As a supplier of the key energy resources and materials that will be in high demand to feed developing economies, and with knowledge intensive industries with excellent R&D links across mining and manufacturing, Australia is well positioned to contribute to develop key low emissions technologies. However, we will only be able to take advantage of this position if the Federal Government commits to a holistic greenhouse emissions policy that does not penalise industry. We need effective æpushÆ polices aimed at leveraging investment in low emissions R&D that are closely linked in to æpullÆ policies aimed at stimulating technology uptake.

Jan 1, 2006

By Carter J. P

A two year study into the effects of coal mining induced subsidence on cliff lines was undertaken by the Department of Mineral Resources with the support of a grant under the National Energy Research, Development and Demonstration Program. A new monitoring technique, using an Electronic Distance Meter and acrylic reflectors attached to the cliffs, provided safety for the surveyors and extensive and accurate three dimensional displacement data on the movement of the cliffs as they were being undermined. The study report included many graphs showing the measured vertical and horizontal displacements, differential subsidence, tilts and strains and included analysis of these movements with various parameters, such as, seam thickness, depth of cover and distances between the reflectors, longwall face and the edge of the chain pillar. Some of these graphs are presented in this paper and could be used, with caution, to predict subsidence movements around other cliff lines, after allowing for differences in geology and mining layout. A mechanism is suggested as an explanation for the observed high horizontal movements around the cliff lines. Sixteen percent of the overall lengths of cliffs that were undermined during the monitoring study fell and the contributions of various factors that appeared to influence the cliff falls are discussed. It is concluded that no single factor dominated as the major cause of the cliff falls and, often, many factors combined to cause cliff face instability.

Jan 1, 1992

It is well known that the ability to influence project value reduces significantly as planning progresses and decisions regarding project parameters are made. However, at the prefeasibility stage in particular, where one of the main aims should be to evaluate a wide range of options in order to select the best for more detailed further study, there is often a reluctance to spend the time and money needed to do this rigorously. This paper demonstrates, by a number of case study examples, how significant increases in value may be obtained by fully evaluating the combinations of alternatives for various project design parameters, including (though not limited to) mining methods, haulage methods, mining rates, processing methods and rates, sequencing of mining, and cut-off grades, with changes and upgrades over time where applicable. The additional value unlocked is typically orders of magnitude greater than the additional cost of the more comprehensive study. The dangers of misuse of simplistic sensitivity analyses and failure to identify how strategies might change in response to changes in external factors are also illustrated, and the importance of selecting the best ægrade descriptorÆ is discussed.

Jan 1, 2007

By G Booth

Whilst communications systems in the mining industry have evolved over the years, the premise remains consistent that reliable communication is vital for safety and operational efficiency. TodayÆs open pit mines are benefiting from advanced developmental efforts based on mesh networking hardware and software technology. This paper highlights Rajant CorporationÆs adaptation of technology, originally developed for the defence and first responder industries, to provide wireless network connectivity in open pit mining applications. Featured is the large-scale deployment of over 300 mobile, meshing access points in the Bingham Canyon Copper mine near Salt Lake City, Utah, the worldÆs largest open pit copper mine. Many companies have positioned themselves, their technology and their product line in the arena of rugged outdoor wireless broadband mesh networking infrastructure. However, Rajant Corporation has combined specialised command and control software and portable networks which offer network extensibility and redundancy that are not available in any other networking solution. Rajant CorporationÆs BreadCrumb« offers unique traits in portability and non-line-of-site networking nodes which intelligently route and broadcast in standard 802.11 protocol. The advantage of RajantÆs solution is especially valuable for users needing equipment moved easily and rapidly into and out of the theatre of operations with uninterrupted network availability. The main differentiators that set the BreadCrumb« network apart from the competitors are mobility (continuous availability), simplicity, ability to properly load balance and power options. In 2007, RajantÆs BreadCrumb« wireless mesh system was selected by the Kennecott Utah Copper Corporation (KUCC), a wholly owned subsidiary of Rio Tinto, as its primary communications platform for operations within the Bingham Canyon Copper mine, the worldÆs largest open pit copper mine. The Rajant BreadCrumb« technology enables KUCC to gain additional operational efficiencies by tracking, monitoring and managing its copper mining operations. The primary goal of using the BreadCrumb« wireless mesh system Kennecott was to streamline its complex mining operations. KUCC required a high number of moving wireless nodes for improving mine monitoring and control. The Rajant InstaMesh« software running on the wireless BreadCrumb« units connects hundreds of devices to each other while rapidly transporting critical operational data. Kennecott has successfully implemented a large number of BreadCrumb« radios in an interconnected network that allows loader trucks, shovels, pumps, laptops and other production equipment to communicate with each other in real-time. These systems are a mix of secure access nodes that enable data and voice communications across a meshed, self-healing network for fleet dispatch, health monitoring and other critical mining applications. Many of the devices that require wireless communications are moving at all times throughout the wireless mining infrastructure. The BreadCrumb« nodes rapidly adapt to any changes in the network topology, assuring that IP traffic uptime and bandwidth are maximised. The installation layout and data network specifics, as well as maps and data network efficiencies will be detailed in the paper.

Jan 1, 2008

By R Jacobs, J Yeates

"The Stockman base metals project is situated in State Forest in the alpine area of East Gippsland, Victoria, adjacent to a National Park and within the headwaters of a major Ramsar-listed wetland catchment and the Murray-Darling River system. Site topography is steep, and elevated (650 m – 1200 m above sea level), and subject to circa 1 m annual rainfall, with occasional winter snowfall. The project consists of two volcanogenic massive sulfide (VMS) deposits to be mined by underground methods and treated in a 1.0 Mt/a central concentrator to produce copper and zinc concentrates for export over a ten year operational life. New resource projects are rare in Victoria. Recognising the sensitive setting, planning for the Stockman Project, which is now in the advanced permitting stage, has focused on balancing economic, environmental and social outcomes to ensure social licence to operate is secured and can be maintained. This has involved close attention to triple bottom line (TBL) risks and outcomes. Stockman has successfully gained State and Federal approvals via the Environmental Effects Statement process. The process of obtaining these approvals has required close attention to effective stakeholder involvement, and management of a lengthy and difficult approvals process, which is still to be finally concluded. This paper is a case study of the process of that permitting and the issues encountered to date. Key learnings from the experience have included: successful approvals require close attention to much more than just the project and its technical aspects and physical setting – effective stakeholder involvement and endorsement is critical the differing consultation requirements for local, regional and government stakeholders, to design and plan implementation of a project to meet TBL objectives, and to gain social licence to operate within the Victorian approvals process, the need for an effective lead government agency with policy authority dealing with material policy change requiring post-closure financial sureties estimating realistic permitting time and cost during the project evaluation phase. CITATION: Jacobs, R and Yeates, J, 2016. Stockman base metals project – sustainability, social licence to operate and permitting lessons learnt, in Proceedings Project Evaluation 2016, pp 98–110 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By T Purvis

Xstrata Copper is extending the Ernest Henry Mine with a 6 Mtpa sub-level cave (SLC) mine being constructed under the pit. The SLC mine will maintain the EHM operation until 2024 after the pit is completed in August 2011. In February 2008, the first cut of the new underground mine at EHM was fired with the start of an exploration decline. Since then Xstrata Copper has continued the development and construction of a SLC mine. During this process a number of challenges arose, some of which had not been anticipated in the planning stages, that in turn has been addressed to ensure the development continued. The challenges have been many and varied and range from setting up the portal area and commencing the exploration decline development in an active large open pit, to management of underground water. Further challenges were presented by the effects of the GFC on investment recommendations, with the scale of the mine varying from a shaft mine to a smaller scale trucking only mine in mid-2009 and back to the full shaft mine in late 2009. The effect was the parallel development of two separate mining scenarios, with the challenge of maintaining commonality for as long as possible to keep both options alive until the final board approval was obtained. In 2010 the RSPT caused further impacts. This paper will describe the current progress of mine development as well as how the various challenges have been met and some key lessons learnt from these experiences.

Mar 21, 2011

By M McCarthy

Over the last six years Mandalay Resources has increased production rates and improved safety outcomes at its Costerfield mine in Victoria, Australia. This mine is an underground operation utilising narrow mining techniques to extract vertical veins, and produces up to 80 000 equivalent ounces of gold per annum, in both gold and antimony value.The operational challenges of narrow vein mining include controlling overbreak when veins being mined are only 300 mm wide. The mine has developed methods and modified equipment to suit extraction of these veins. Productivity improvements over the period have involved development of a stoping method and equipment to suit 1.8 m wide development drives. Over the last five years and during a skills shortage, recruitment, training and retention of personnel has been key to keeping corporate knowledge and skills to execute a careful efficient mining technique to minimise overbreak.Managing an underground operation close to nearby residents has unique challenges. Historically Victorian residents had family members work as underground miners; however, in the current day with few underground operations in this jurisdiction, community knowledge of mining has decreased. The Costerfield Operations are only 100 m from the nearest residence and the company values community engagement, partnership and investment with local Heathcote organisations.The mine has invested substantially in executive coaching of its leadership team early, which has paid dividends in problem solving potential of that team and ensuring the operation delivers on its promises to all stakeholders. The operation has become safer and employees are now more aware of their individual contribution in producing safe, efficient gold and antimony that benefit the whole operation, community and the region.CITATION:McCarthy, M, 2016. Costerfield – a narrow vein case study, in Proceedings International Mine Management Conference, pp 331-338 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By A Fern, A Hawkes, o, T Vincent

The modern workplace has changed dramatically in recent years with an increased emphasis on the psychological well-being of employees. While adhering to a certain standard of psychosocial safety at work is now not only a moral, but legal obligation in Australia, it begs the question: how can organisations begin to ensure psychosocial safety? A positive psychosocial safety climate is one where employees feel they are psychologically safe, feel supported in their work and are not exposed to work-related stressors that can negatively affect their mental health. Such a climate can help boost productivity and create a more positive working environment. This presentation will provide a twopronged approach to understanding and managing psychosocial safety: pairing a traditional risk assessment with climate measurement. Risk assessments can provide several benefits, including identifying and characterising work-related hazards, identifying the nature and severity of the risks to employees and prioritising necessary interventions for reducing or preventing psychosocial harm in the workplace. However, these assessments can have certain limitations, especially when it comes to capturing some of the less obvious causes of psychosocial harm. Climate measurement can provide valuable insights into employees’ perceptions of the work environment, identify areas of concern that may not have been identified in the risk assessment and help to guide organisational changes that will enhance employees’ psychosocial well-being over time. It will also be argued that climate should be assessed from a broad perspective exploring general, physical, social and psychological aspects of safety climate. This presentation will explore why conducting risk assessments in conjunction with detailed climate measurements is integral to protecting the psychosocial safety of employees in the workplace and demonstrate why employers should view the two approaches as complementary and interconnected. Best practice recommendations will be provided for the risk assessment, climate measurement and psychosocial interventions

Apr 16, 2024

By J V. Mehrabani, A R. Sayadi

Adequate estimation of equipment costs is a key factor in a feasibility study and in evaluation of design alternatives for mining and mineral processing projects. Inaccurate early cost estimation could lead to the elimination of investment benefits. However, this estimation is complex and time consuming because of data accessibility problems and consequently access to a rapid, up-to-date and accurate tool is desirable for carrying out cost estimations.This paper describes the development of models for estimating capital and operating costs for a jaw crusher, which is used as the primary crusher for a wide variety of mineral beneficiation plants, applying single and multivariate regression analyses, together with the design of experiment approach, based on principal component analysis. Explanatory variables include gape size, length of feed opening and power as numeric (quantitative) variables and toggle type (single or double) and the existence of extra heavy duty construction as categorical (qualitative) variables. The performance of each model has been investigated and comparing the estimated R-squared (R2) of each model, the best was selected and its validity examined. The cost models include the capital and operating costs along with the operating cost components. The results indicate that the suggested best cost model is sufficiently accurate for use in feasibility studies.

Sep 26, 2011

By Brown AP

Comparison of legal permits required for mining (as opposed to prospecting or exploration) in New Zealand, under the Mining Act 1971 and the Resource Management Act/Crown Minerals Act 1991. Mining generally receives the same treatment as any other industrial or commercial activity.

Jan 1, 1995

The celebrations which took place in 1986 to mark South Australia's Jubilee 150 served to focus attention on all aspects of the State's heritage. Until that time the sites and relics of South Aus- tralia's early mines had been generally neglected. Marked by the ruins of enginehouses and littered with the remains of the massive technology of the Industrial Revolution, these sites have now been recognised as containing the threads of a fascinat- ing story. In the early days of settlement the economy of the Colony was based on land and farming. Droughts caused periods of economic depression which were alleviated by chance discoveries of gold, lead, silver, and copper ore. Some of the mines which were opened on the copper deposits were the largest in the world at that time and their names well-known throughout mining circles. Working by hand with primitive equipment, the early miners excavated vast networks of shafts and stopes often extending to great depths: at Moonta- Wallaroo Mines for example workings extended to 860 m below ground. Because of the presence of underground water, mining to these depths would not have been possible without the Cornish pumping engine. Operated by steam power these massive engines and their associated equipment were transported from Cornwall by clipper and delivered to the mines by bullock cart. At this time the engines were at the peak of their devel- opment and, although expensive to import and install, they were highly reliable: the engine oper- ating Hughes pump at Moonta worked continu- ously for sixty years without a major breakdown.

Jan 1, 1987

Most Geologists have a well rounded knowledge of the exploration phase and those who have worked as mine geologists have an understanding of the production phase. Few have had exposure to the development and the construction phases. Even fewer have had the experience of closing a mine, disposing of the plant and equipment, carrying out the final cleanup and making the area safe and environmentally acceptable.During the various phases of exploration, the geoscientist gains a wealth of non-geological information which can be of considerable value to engineers and technicians in the feasibili-ty, development, operation phases and finally the closure of a project. Such basic controls as surveys, adopted assay sample lengths and the location of items of infrastructure during exploration, may continue to affect the project through its entire life. Thus the geologist's responsibilities extend well beyond the explo-ration phase of a project.

Jan 1, 1990

By J Harris, P Kirsch, D Cliff, M Spinks, S Goater, D Sprott

Fires are a common and recurrent unwanted event in the operation of open pit mines. In most cases, the causes of events such as fires are already æknownÆ but are either overlooked or not fully addressed in planning. Ongoing rapid growth of the global mining industry is creating a scarcity of skilled personnel, and high turnover within operations. This contributes to loss of corporate memory in risk management activities. RISKGATE« is an online risk management system designed to support and assist in the analysis of priority unwanted events in Australian coal mining operations. Funded by the Australian Coal Association Research Program (ACARP), RISKGATE« is a knowledge management program that delivers best-practice controls for unwanted events and assists operations in staying abreast of emergent risks and threats. RISKGATE« content has been primarily developed from an association of industry experts, and enriched with input from additional academic and technological resources. In mining operations, RISKGATE« provides a continuum of knowledge and best practice for risk identification, assessment and management. RISKGATE« will assist companies in improving safety performance, operational efficiency, operating practice and training. Here we present the RISKGATE« prototype as developed in 2011 for Fires, with a case study presented for the initiating event Fires on Mobile Plant.CITATION:Harris, J, Sprott, D, Spinks, M, Cliff, D, Goater, S and Kirsch, P, 2012. RISKGATE« - A case study in application to fires on mobile plant, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 49-54 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By Weatherhead J, Grounds J

The Nabarlek Uranium Project located in Arnhem Land in the Northern Territory of Australia was a small high-grade deposit which was the first uranium mine brought into operation following the extensive Commissioner Fox Inquiries into uranium mining during the late 1970s. The operation is almost complete and decommissioning plans have been prepared. This paper reviews all phases of the water management and tailings disposal for the project and compares results with design predictions.

Jan 1, 1988

By P M. Hetherington, M P. Murphy, K E. Crook, F Pym

Resource characterisation is critical for informed decisions in both strategic and operational space. The sources of information for resource characterisation are limited by: direct measurement of resource attributes, such as grades, rock-types, mineralogy, and are available only from sparse locations, ie drill holes; or indirect geophysical measurements such as seismic, gravity or electro[1]magnetic survey. Data collection tools, methods, and processing technologies are constantly improving providing a broad spectrum of options for data collection strategies. The cost of each data survey varies from thousands to millions of dollars with the value of each additional data having diminishing return for a particular business decision. The value of information analysis provides the optimal decision on data collection strategy within a limited available budget. This work presents an example of value of information analysis for new Blast Hole Assay Tool (BHAT) and Reverse Circulation Grade Control (RCGC) data used in addition to the wider spaced exploration data. The value of information is quantified in terms of reduction of grade uncertainty, ore loss and dilution by comparing different combinations of data collection methods. Four different strategies were considered: exploration samples in addition to 50 per cent of blastholes surveyed with BHAT, exploration samples in addition to 33 per cent of blastholes surveyed with BHAT, exploration with wide-spaced RCGC data, and exploration without additional grade control. For each strategy the observed values have been simulated using advanced multivariate geostatistical simulations and compared with simulated ground truth models. The calculated uncertainty, ore loss and dilution informed the optimal data collection strategy. Opportunity to reduce sample density from the nominal 50 per cent of drill holes was evaluated.

Mar 22, 2022