Search Documents

By M Creech

During the 1990s, wider and more productive longwall panels were being introduced into the Newcastle Coalfield. The strata of the Newcastle Coalfield incorporate numerous massive sandstones and conglomerates, some of which formed the immediate roof of the coal seams being mined. The unexpected implications of introducing wider panels into this geological environment included more variable and increased subsidence, severe periodic weighting (with associated mid-face falls) as well as windblast.Subsidence prediction at the time was based on empirically derived data essentially relating subsidence to the width/depth ratio of the panel without accounting for actual widths, nor the impacts of variable geology. This approach required modification as locally derived data was gathered and reinterpreted.The interaction of massive strata located close to the roof of the mined seam resulted in dramatic implications for some of the operations. When associated with longwall goaf geomechanics severe periodic weighting events and crippling mid-face roof falls were the consequence. When associated with narrower panels and shortwall goaf geomechanics, mines in the region experienced aggressive windblast events. The relationships between the overlying massive strata, longwall panel geometry and the various risks encountered during this period is in the author’s opinion, the most concise still documented.As the extensive coalfields of Queensland turn to underground mining operations the relevance of these experiences cannot be underestimated. This paper will discuss recent developments as well as incorporating diverse subjects such as microseismic monitoring, low frequency radio emissions and ‘electrophonics’ as they relate also to the topic.Like Moriarty, massive strata can be disguised and can offend when you least expect. This paper documents a trail of crimes committed by conglomerate in the Newcastle Coalfield that were inflicted on the general public, miners and mining equipment. Although this paper concentrates on the criminal behaviour of conglomerate, this story is also relevant to other massive units such as coarse sandstones that may be more difficult to identify and apprehend. Currently Moriarty remains at large and able to reoffend at any time, once again taking advantage of the unwary.CITATION:Creech, M, 2014. Moriarty was a conglomerate – experiences and implications of coal mining under massive strata in the Newcastle Coalfield, in Proceedings Ninth International Mining Geology Conference 2014 , pp 47–54 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By S Coward, S Jackson, S Moayer, J E. Vann

The variability and uncertainty of mineralisation, coupled with subsequent uncertainty in mining and processing, is often paid scant regard or overlooked during the evaluation of mining projects. In many instances, when the project transitions to the operational phase, the reality of feed or product variability and the consequences of unquantified uncertainties throughout the value chain become obvious. The outcome is the familiar picture of frequent ramp-up underperformance and failure to deliver on planned targets and objectives.Both mine and exploration geologists are expected to generate mineral deposit models that are based on an integration of diverse sources of data. These multifaceted deposit models already play a pivotal role in the design, development and optimisation of mining project value, and the trend to a fully digitally engineered future means that this importance is increasing. It is therefore vitally important that tools be made available to the geologist (as well as mining engineers and metallurgists) that enable them to characterise and assess variability and uncertainty via appropriate deposit models and thus articulate their impact on potential project configurations and decisions. Scenario-based project evaluation (SBPE) provides a framework for full and proper analysis of the downstream impacts of inherent deposit variability and uncertainty on project performance.SBPE has been developed by the authors over several years and aims to propagate geological uncertainty and variability through the mining value chain. The outcomes of SBPE can be tested against future external scenarios capturing financial, economic and socio-political factors that also drive project performance. Stochastic representations of the orebody (via conditional simulation (see Chilès and Delfiner, 1999)) that explicitly incorporate variability and represent uncertainty are propagated through the value chain on a block-by-block basis (ie on a much more granular basis than traditional project evaluation approaches).Conventionally, metallurgical processes are modelled with deterministic equations (eg regression models) based on limited data. The SBPE approach allows for the modelling of process performance uncertainty using geometallurgical sampling fully. Multiple outcomes of SBPE are passed through financial modelling, which can also incorporate stochastic components, thus allowing full quantification of the risks and opportunities of a set of project alternatives. The value of the SBPE system is that once a base case has been established, multiple engineered alternatives coupled with external scenarios are easily evaluated and compared in terms of incremental value.A new case study of SBPE is presented that shows how, by analysis of the various aspects of variability and uncertainty, project managers are able to focus on the areas that have the greatest ability to reduce risk and/or add significant value. This can lead to sufficient flexibility being built into operations that allow operators to cope with the real orebody delivered to the plant.CITATION:Jackson, S, Vann, J E, Coward, S and Moayer, S, 2014. Scenario-based project evaluation – full mineral value chain stochastic simulation to evaluate development and operational alternatives, in Proceedings Ninth International Mining Geology Conference 2014 , pp 21–32 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By T Berryman, C Adams, L Griesel, C Buxton

The Kalgoorlie Consolidated Gold Mines (KCGM) schedule model is used for short- to medium-term planning and scheduling at the Fimiston Open Pit Mine (the Superpit). The model bridges the gap between grade control models, which are generated one to seven days prior to mining, and the annual Resource and Reserve model update that is used for budget and life-of-mine plans. The schedule model uses close-spaced grade control data (up to 20 000 m drilled each month) as well as resource definition drilling to estimate production volumes three to six months ahead of current mining. From this, a rolling 12 week mining and processing schedule is generated on a monthly basis. As the KCGM operation is mill and sulfur constrained, the schedule model needs to be an accurate predictor of ounces as well as tonnes, gold and sulfur grades. The process must also be time efficient in order to meet monthly planning and reporting deadlines. Due to the large amount of new data generated each month, model updates using conventional interpretation and estimation techniques have proven to be impractical and too time consuming. This paper will examine the evolution of the Superpit schedule model process over time, recent improvements and the effect of different model outcomes on short- and medium-term mine planning.CITATION:Griesel, L, Buxton, C, Adams, C and Berryman, T, 2014. The superpit schedule model – A time-efficient data-driven estimation for short- and medium-term planning, in Proceedings Ninth International Mining Geology Conference 2014 , pp 397–410 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By J Taylor, A Dubowik

To increase the efficiency and improve the quality of diamond drilling at Olympic Dam, mine geologists have adapted and modified common practices in order to overcome the challenges imposed by such a unique environment. Mine geologists have to take into account both the complex geology during the diamond drill hole design phase, as well as incorporating diamond drilling into the larger-scale scheduling process already employed at Olympic Dam. This study seeks to explore how such modifications have evolved over time.The geology of Olympic Dam influences the design process of diamond drill holes, particularly due to the variation of lithology and alteration, as well as the presence of magnetite and major structures within the orebody. Exclusion zones are used to manage interactions with existing and planned mining activities, and their size is dependent upon the geology of the area. Specific deviation checks are used to monitor the deviation of diamond drill holes with respect to these?zones.The highly interactive environment of Olympic Dam requires unique planning for diamond drilling, resulting in the production and implementation of both long- and short-term schedules. Long-term schedules are targeted at determining drilling locations and ensuring drilling is completed prior to stope planning, while short-term schedules aid in enabling access to ensure timely set-up of drill sites. Estimated drilling rates, determined by expected lithologies and historical data, feed into the short-term schedule to assist in managing the operation and minimising the downtime of diamond drill rigs. A mine geologist is appointed as a diamond drill coordinator to organise and manage diamond drilling at a scheduling and operational level, streamlining the entire process.Analysis of historical data shows a strong correlation between implementation of the aforementioned practices and improved drilling rates. This study shows the importance of adapting universal tasks to particular environments and circumstances. Mine geologists at Olympic Dam continue to acquire knowledge to further improve the modified drilling practices as operational requirements, production pressures and economic factors change.CITATION:Taylor, J and Dubowik, A, 2014. The evolution of diamond drilling practices at Olympic Dam, in Proceedings Ninth International Mining Geology Conference 2014 , pp 271–280 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By J Channell, G Phillips

"The Chesney deposit, located 4 km south-east of Cobar consists of three copper-gold rich shoots that lie within a larger, copper dominant lode. A fourth gold rich shoot is located adjacent to the main deposit. The deposit exhibits a strong structural control on mineralisation, as brittle deformation during subvertical extension provided the requisite structural traps to precipitate sulfides from solution. It is postulated that the Great Chesney Fault acted as a fluid conduit, conveying fluids to the site of orebody formation. The continual supply of fluids resulted in cyclic brittle deformation when the fluid pressure exceeded the lithostatic pressure and the tensile strength of the Great Cobar Slate.Evidence supports the hypothesis that ore deposit formation was controlled by: a supply of mineralised fluids transported along the Great Chesney Faulta suitable location for the mineralised fluids to accumulate, accommodated by vertical extension and dilation in certain locationsthe creation of suitable structural traps to capture the sulfides. These traps formed as a result of fault-valve behaviour. Understanding the controls on mineralisation enables prediction of the location of other deposits with similar emplacement history, or extensions of current deposits.CITATION:Channell, J and Phillips, G, 2014. Understanding mineralisation controls – a case study of the Chesney deposit, in Proceedings Ninth International Mining Geology Conference 2014 , pp 301–312 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 18, 2014

By T Wellman, G Sternadt, R Hingston

The 335 000 oz Wilber Deposit is located within the Meekatharra-Wydgee Archaean greenstone belt in the Murchison District of Western Australia. The deposit comprises high-grade gold mineralisation hosted within a steeply west-dipping quartz lode, which lies within a broader (20–60?m) north-east striking shear zone envelope. Locally, the northerly-trending host rock geology includes greenschist facies high-Mg basalt (albite, actinolite, chlorite, biotite, calcite, zoisite, muscovite and titanate) intruded by at least two generations of felsic to intermediate porphyries (albite, actinolite, zoisite, chlorite, sericite, biotite, quartz and titanate). The Archaean rocks are cross-cut by a number of east–west striking Proterozoic dolerite dykes (biotite (50 per cent), albite, carbonate, epidote, titanate and actinolite) that are interpreted to have intruded pre-existing regional structures. The entire mine package is cross-cut by a system of shallow north-east-striking, north-west-dipping, barren quartz veins that commonly contain large (up to 30 cm), euhedral, smokey quartz megacrysts.The north-east-trending lode lies within a 3 m wide shear zone and varies from a single discrete 0.5 to 4 m wide laminated, massive or brecciated quartz-carbonate vein to multiple laminated veins up to 1 m wide within the shear. The veins exhibit strong boudinage, with cross-cutting quartz-carbonate seal veins in the boudin necks. The boudin necks often contain pink calcite. The shear zone fabric wraps closely around the boudin necks proximal to the vein, becoming more lode parallel distal to the vein. The lode is offset by a north to north-north-west trending fault.Mineralisation occurs as free gold within the quartz carbonate veins, with accessory sulfides including pyrite ± chalcopyrite, ± galena ± sphalerite. Fuchsite is observed in the veins, as laminar wall rock inclusions, with visible gold commonly associated with the wall rock laminations.Gold grades range from less than 1 g/t within the hosting shear zone, either at the margins or interstitial to the veins, to approximately 30 g/t in the single vein, and up to greater than 60 g/t in the multiple vein areas. Gold is commonly visible and disseminated throughout laminated, breccia and massive quartz veins, although laminations show the highest concentration of gold grains.CITATION:Hingston, R, Wellman, T and Sternadt, G, 2014. The geology of the Wilber Deposit, Andy Well Gold Project, Murchison District, Western Australia, in Proceedings Ninth International Mining Geology Conference 2014 , pp 55–64 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By R O’Sullivan, D Taylor, J G. McLellan, B Miller

The Mount Isa copper deposit is located adjacent to the city of Mount Isa, Queensland, and lies within a series of Palaeoproterozoic to Mesoproterozoic Superbasins. The deposit is hosted almost entirely within the Urquhart Shale (US), a unit of the Mount Isa Group sediments and part of the Isa Superbasin. The copper mineralisation is separated into two distinct orebodies: the X41 mine (1100 and 1900 orebodies) and the Enterprise mine (3000 and 3500 orebodies). The orebodies are situated in the hanging wall of the major controlling structures, the Paroo Fault, which has juxtaposed older basement Eastern Creek Volcanics against the younger Mount Isa Group sediments cf 1655 ± 4 Ma. Conjecture remains over the exact timing of this thrust event. However, it is clear that inflections on the Paroo Fault have a close association with the orebodies and are an important structural feature in the mineralisation of the Mount Isa copper deposit.The life-of-mine is reducing steadily and new geomechanical modelling techniques were employed to target structurally controlled mineralised zones in three dimensions. Following a structural review of the mine using underground mapping, structural data and core shed observations, a conceptual 3D mine model was constructed utilising existing data modelled in MineSight®. This conceptual model included all the main lithological units and structures. The conceptual model aimed to test the effects of deformation on the main lithological and structural components of the system and attempted to highlight areas of anomalous stress and strain that may indicate a higher likelihood of fluid focusing and mineralisation potential. This project was focused on testing the latter stages of a D3 event (NE–SW compression) and D4 event (SE–NW compression), which are considered to be responsible for the current location of the mineralisation.The fully coupled 3D finite element analysis models resulted in highlighting anomalous patterns of stress and strain and subsequent fluid flow as a result of the two deformation events. The NE–SW D3 simulation provided the best correlation with the known distribution of mineralisation. This event also indicated several areas on the Paroo Fault and within the US that have potential to host further areas of mineralisation. The SE–NW D4 simulation provided less of a correlation with known mineralised zones. However, this event may have been responsible for post mineralisation re-mobilisation of copper on a relatively small scale. Areas of maximum shear strain, shear stress, volumetric strain and fluid flow correlated well with areas of minimum principal stress and provided the best overall match with known mineralised zones. Furthermore, several additional highlighted areas provide a high potential for further discovery of copper mineralisation. Recent exploration drilling north of the Enterprise mine 3000 orebody, utilising geomechanical modelling as part of the targeting criteria, intersected copper mineralisation, providing further validation of the modelling results.CITATION:McLellan, J G, O’Sullivan, R, Miller, B and Taylor, D, 2014. Geomechanical modelling of the Mount Isa copper deposit – predicting mineralisation, in Proceedings Ninth International Mining Geology Conference 2014 , pp 197–206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By I Treloar, T Elenbaas, E Isaaks

Critical reviews of grade control generally focus on blasthole sampling and the estimation of ore control block model (OCM) grades, with little or no attention given to dig-line design. For example, the estimation of block grades is deemed important as estimation errors lead to the misclassification of ore types and subsequent dollar loss. Recognition of the problem that the underestimation of block grades may be more or less costly than overestimation led to the application of loss functions to the classification of individual OCM blocks by ore type. The method is known as maximum profit selection (MPS). However, each OCM block may be misclassified a second time by dig-line design. Although each block may initially be assigned an optimum ore type by MPS, OCM blocks are seldom individually mineable by ore type. As a result, a common solution to this problem is the design of mineable polygons or dig lines loosely constrained by a minimum mining width. All material within a properly designed dig-line polygon can be mined and sent to a single destination such as the mill, stockpile or waste dump. These dig lines are often designed manually or by simple variations of computer-generated contour lines. They are generally suboptimal and result in additional misclassifications of ore types. This paper provides an algorithm for constrained optimum dig-line design where dig-line misclassifications are also evaluated through loss functions or MPS. Constrained optimum dig-line designs minimise the dollars lost by dig line misclassifications for a given minimum mining width constraint. A case study is provided illustrating constrained optimum dig-line design and subsequent benefits.CITATION:Isaaks, E, Treloar, I and Elenbaas, T, 2014. Optimum dig lines for open pit grade control, in Proceedings Ninth International Mining Geology Conference 2014 , pp 425–432 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By G Fahey, S Rose

"Mining geology as a defined profession is only about 100 years old. The successful modern mine geologist needs to be a multidisciplinarian, but also needs to maintain a focus on the key outputs of the role. The technical skills needed in the role have increased as mining methods move to increasingly mechanised techniques. As well as being the guardian of the orebody and ensuring minimal dilution to expected ore grades, the mine geologist should be competent in the 12-point mine geology process. The mine geology process should include:a statement of purpose (a ‘mission statement’)geological mapping/logging system that supports consistent and regular geological data collection, storage, and interpretationsampling system that can produce representative samples and fits in with the mining scheduleassay database with relevant controls to ensure only ‘clean’ data is loadedsimple quality assurance / quality control (QA/QC) system for samples and assays, with a response process to react to out of specification resultsconsistent method of exporting, visualising, processing and interpreting assay data to create mining blocksdevelopment sign-off system so that all development and stoping is controlledproduction tracking system to monitoring and reporting what ore and waste volumes have been moved from the face, to any intermediate stockpiles, the run-of-mine (ROM) pad and into the crusherreporting system for daily, weekly and monthly reporting of tonnes and gradesdocumentation so that the grade control system has simple, but effective descriptions of how it works, who has responsibilities, and authorities, and be easily maintainedreconciliation system to compare resource and reserve to grade control and to mined and milledtraining system so that the geology team can quickly become competent.In this paper, the authors discuss the requirements of each point, and comment on common shortfalls observed by them over several years’ experience on producing mines worldwide.CITATION:Rose, S and Fahey, G, 2014. Modern mining geology, in Proceedings Ninth International Mining Geology Conference 2014 , pp 461–466 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 18, 2014

By R Sterk, B Reid

The Konongo Gold Project is located on the western margin of the 125 Moz Ashanti Gold Belt in Ghana, West Africa. It is situated 60 km along strike of the world-class mineral system at Obuasi and is interpreted to lie on the same controlling regional shear system.The project is operated by Signature Metals, a subsidiary of the Liongold Corporation, and is managed and funded by the Liongold Corporation.Historic underground operations at Konongo produced 1.6 Moz Au at a head grade of 11.8 g/t Au, from eight operations spread along 16 km of the shear system. Mining focused almost exclusively on free-milling gold in quartz, ignoring the gold-bearing sulfide mineralisation associated with the quartz veins. Underground mining ceased in 1986.In 2013, Signature Metals re-focused the program at Konongo to assess the viability of mining the sulfide ore sustainably. This led to the first campaign review of the historic underground data and resource potential since mine closure. The Obenemase mine was the first of the eight operations to be assessed as part of this campaign.Large amounts of legacy data have survived for Obenemase and several historic resource estimations have been completed based on these data. The data typically consisted of hand-drawn sections and plans, and ledgers of commonly incomplete drilling and sampling data. Some drill core have been lost over time, but a large amount of quarter-core and half-core as well as pulps and rejects are still available. Previous resource estimates had a low confidence value because all the available assay and geological data were integrated effectively with the estimates, resulting in a lack of understanding of both grade and geological continuity.This project built a new geological model for Obenemase that greatly enhances the understanding of the controls on mineralisation using a thorough approach of re-surveying, re-cataloguing and re-logging. This model led to an increased degree of confidence and a subsequent upgrade of resource classification, and created several previously unrecognised strong exploration targets. The resulting resource estimates increased the value of the project by 100 per cent.This paper emphasises and highlights the importance of a well-understood geological model on the confidence of a resource estimate and how this may directly impact on the project’s ‘bottom line’.CITATION:Sterk, R and Reid, B, 2014. The Konongo Gold Project, Ghana – an example of how geology makes all the difference to a resource estimate, in Proceedings Ninth International Mining Geology Conference 2014 , pp 467–476 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By Jesús Velapatiño Pacheco

El presente texto refiere dos temas importantes en seguridad minera: seguridad eléctrica y salud y seguridad ocupacional dentro de una auditoría de seguridad realizada como parte de la política de las empresas mineras y afines. Por ello, el documento describe el incumplimiento de las instalaciones y actividades eléctricas a la normatividad vigente en seguridad eléctrica y salud ocupacional, los cuales fueron identificados en una auditoría de seguridad que fue realizada en minas y plantas concentradoras. Luego del diagnóstico, se propone elaborar un carné de proyectos con el correspondiente presupuesto, el que se pagará con los beneficios generados: los ahorros posibilitados (disminución y control de pérdidas) y con la mitigación de multas previstas para el pago de los incumplimientos. Finalmente, se formula una matriz de soluciones (recomendaciones) donde se medirán los impactos de la implementación del carné de proyectos de mejora de las instalaciones eléctricas.

Aug 1, 2014

By Airong Zhang

El presente texto señala los elementos importantes de una licencia social para realizar operaciones mineras en un determinado territorio. En ese sentido, el desarrollo de este proceso permitirá que las comunidades dialoguen con los inversionistas y a su vez les otorgará confianza en el camino de la exploración minera. Para ello, se muestra un ejemplo aplicado a una comunidad minera denominada Queensland, Australia donde a través de doce encuestas desarrolladas durante 12 meses, se percibío la trascendencia no solo de la gestión, sino el contacto de las comunidades y las compañías mineras y evitar conflictos sociales.

Aug 1, 2014

By Rebecca Darling

El texto describe la importancia del agua en la minería a partir de la integración de enfoques técnicos y sociales para la gestión sostenible del líquido elemento en las comunidades aledañas. Por ello, se describen los riegos típicos de agua que las compañías enfrentan y plantea las posibles soluciones para tener un entorno minero más operativo. Entre estas resoluciones tenemos: la alineación interna, la comunicación estratégica y la cogestión de recursos (un espectro de monitoreo participativo para la toma de decisiones compartida.

Aug 1, 2014

By Dirk Arts

En el 2012 Río Tinto minera inició el diseño del sistema de monitoreo y evaluación para medir el desarrollo social del proyecto La Granja en Cajamarca, Perú. En este sentido, el presente texto señala la medición de este desempeño social a través de un sistema comprendido en cuatro pilares como: seguimiento del compromiso de las partes interesadas y el manejo de las realciones comunitarias, medición de los resultados directos del proyecto y cómo contribuyen en el impacto social (modelo de resultados), el monitoreo de las tendencias y cambios sociales a nivel local y doméstico y el monitoreo de la reputación y nivel de consenso social. El objetivo es identificar el alcance, contribución y grado de influencia del proyecto La Granja en el cambio e impacto social.

Aug 1, 2014

By K H. Esbensen

The Theory of Sampling (TOS) has contributed significantly to chemometrics by allowing data analysts to become more aware of total measurement uncertainty as total sampling error + total analytical error. This has allowed a new view on, for example, validation of multivariate data models and their performance. This keynote focuses mostly on the reverse perspective: how can chemometric multivariate data modelling be of help in an augmented sampling context? The basic principles of multivariate data analysis are presented and application examples are outlined from several areas in the geosciences to facilitate answers to the question posed, including a geochemical multivariate anomaly concept defined by a multivariate background model. Applications from geochemical prospecting, geochemical mapping, environmental chemistry and anthropogenic outlier recognition are outlined, as are the interdependent relationships between geostatistical modelling (variographics) of singular variables versus linear combinations of a multitude of variables, in chemometrics called scores. The potential synergy between chemometrics and TOS is far from exhausted at this time; much work remains.CITATION:Esbensen, K H, 2014. Theory of sampling in a multivariate perspective – what can chemometrics contribute?, in Proceedings Sampling 2014 , pp 7–10 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By J Ta’ala, M Handyside

Mechanical sampling from conveyors has historically been a staple in the iron ore industry when information related to chemistry, sizing and moisture is required. In order to comply with ISO 3082:2009, samples can be taken either on a mass or time basis provided no bias is introduced by periodical variation in quality or quantity. With the introduction of mechanical sample carousels, you also have the opportunity to collect samples on a mass or time basis. In order to optimise automatic sample stations in a changing production environment, BHP Billiton Iron Ore (BHPBIO) has developed a simulation model that enables the various combinations of mass–mass, mass–time, time–time and time–mass to be investigated.The sample station model can utilise actual (variable) feed rates to achieve high resolution and enables the simulation of sample size variation. Cutter speeds and other settings can then be adjusted to better optimise the performance of the sample station with regards to optimal sample size as well as ensuring the sample station is in compliance with ISO 3082. The model can also assist process engineers in adjusting settings to better optimise the sample station and reduce unwanted events such as blockages. The model can be easily modified to conform to various sample station designs. This paper demonstrates the use of the model and the benefits that can be achieved.CITATION:Handyside, M and Ta’ala, J, 2014. Simulating time versus mass basis?sampling, in Proceedings Sampling 2014 , pp 155–164 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By P J. Jacobs

FORACO is the third-largest global drilling services company, and recently celebrated its 50th anniversary. The company’s historical roots are in French-speaking West Africa, delivering hydrogeological drilling services to resource companies, villages and regional centres. Today, FORACO operates over 300 drill rigs in more than 20 countries.The Asia Pacific region of FORACO runs a fleet of 37 late model drilling rigs servicing the diamond drilling, reverse circulation, coal, coal seam gas and hydro drilling sectors.FORACO Australia has extensive experience delivering large diameter coring (LDC) samples to the resource community. In the past three years, the company has been involved in six 8? coring projects in a variety of geographies and geologies, including iron ore, coal and uranium. FORACO has developed proprietary equipment and techniques to deliver cost-effective LDC samples with outstanding core recovery.The FORACO LDC sampling system is hands free, with mechanised rod and corebarrel handing to minimise the risk of manual handling injuries. Sample volumes are six times PQ (the common industry standard for large core samples), with core recoveries consistently above 96 per cent in extremely difficult formations.Eight inch coring is a conventional coring system suited to hole depths up to 150 m. For deeper applications, FORACO has recently invested over $4 M in a 6? wireline coring system capable of achieving depths of 300 m.CITATION:Jacobs, P J, 2014. Large diameter core sampling, in Proceedings Sampling 2014 , pp 71–76 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By G J. Halstead, R C. Steinhaus

The True Pipe® in-line sampler was developed in an attempt to address the need for a mechanically reliable and correctly designed sampler to suit one-dimensional pressurised slurry pipelines, often found in metallurgical process plants but for which no reliable and representative sampling solution as yet exists.The design, whose operation is based on the principle of symmetry, is described by Dominique François-Bongarçon (2005) with the synchronous opening and closing of relevant valves. It representatively isolates portions of the particulate material stream at predetermined intervals for effective extraction of primary increments for subsequent sample compositing.Theory of Sampling applicable solutions have proven elusive in flowing pressurised particulate material streams, with various attempts to date not having formulated a viable, mechanically reliable and acceptable design.Compliance to sampling theory is critical, and a number of tests were conducted where certain operating parameters were altered to determine their influence and sensitivity on sampling representativeness.The results of the initial series of tests performed on a carefully designed rig are presented, with additional work discussed for necessary investigation in the near future.Getting closer to a robust, economic and correct design for this challenging application in the minerals industry may now not be that far away. Plant management staff will see improved metallurgical mineral balances around their process plants and significantly reduced sampling discrepancies, particularly in tailings applications. Improved quality control is now possible where, due to plant head room constraints, classical cross stream sampling methods cannot be employed.CITATION:Steinhaus, R C and Halstead, G J, 2014. True pipe sampler – a correct design utilising the principle of symmetry in pressurised slurry particulate streams, in Proceedings Sampling 2014 , pp 127–134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By D Laskovski, T Nguyen

Flotation surveying can be an extremely powerful means of determining opportunities for circuit optimisation and benchmarking. The type of survey employed depends heavily on the nature of the information required from the survey. It follows then that the type of survey determines the type of samples required; however, regardless of the type, the success or failure of a survey is often dependent on the correct used of appropriate sampling techniques at each sampling point. For a successful flotation plant survey it is vital that the correct samples be collected at the correct time in respect to the feed and each other. This paper discusses the current best practice sampling methods used in flotation surveying and discusses in detail the ideal sample masses based on theoretical analysis. Comparisons with JKTech’s database of real plant operations will then be made.CITATION:Laskovski, D and Nguyen, T, 2014. An investigation of current flotation survey sampling, in Proceedings Sampling 2014 , pp 99–106 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

By D François-Bongarçon

The theory of sampling (TOS), and therefore representative sampling, is based on three fundamental principles: sample correctness, which handles the search for non-bias; segregation, the effects of which must be eliminated or minimised; and variance control to help achieve the desired reproducibility. After briefly reviewing these very few, albeit essential first principles of Gy’s TOS, the state-of-the-art in TOS is examined through the prism of these principles and the prospects for the future are explored, with suggestions for further research where relevant. Regarding segregation, which is currently the focus of much research, new orientations are proposed. For correctness, which takes on a major importance when it comes to sampling devices, some new, important principles that have been put forth by recent research, are described in details.CITATION:François-Bongarçon, D, 2014. State of affairs and current research trends in theory of sampling fundamentals, including segregation and correctness, in Proceedings Sampling 2014 , pp 11–16 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014