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By Nixon J. C, Reynolds C

Three principal features of the ore at Captain's Flat, New South Wales, tend to complicate concentration of the valuable minerals, these being:1. The ore occurs in three more or less separate bodies which vary in texture and mineral ratios. Mining of constant proportions of the three sections, or adequate blending of the ore, is not fully effective, and consequently the flotation section is subjected to feedof varying texture.2. The mineral association in the heavily pyritic ore is extremely intimate. Composite particles exist even at 20 micron sizeI, and probably finer.3. The copper content of the ore averages_about 0,6%, which is high enough to justify recovery of the chalcopyrite in a separate concentrate. A review of the metallurgical history of the mine shows that this feature has been the cause of the several major changes in flowsheet of the flotation section since the commencement of milling.METALLURGICAL HISTORYThe mine started production in January 1939, at the rate of 250 tons per day of sulphide ore, assaying 0·68% Cu, 6·52% Pb, 10·8% Zn, and about 1 dwt. Au and 2 oz. Ag per ton.

Jan 1, 1952

By C J. Unger, T Baumgartl, C J. Bond, P Sabourenkov, V C. Glenn

Social licence to mine is influenced by society’s perception of the mining sector’s ability to effectively rehabilitate mined land and for governments to appropriately regulate that process for the broader community benefit. In Queensland, Australia, many mine rehabilitation personnel working for active coalmines, as either staff, consultants or contractors, belong to the Central Queensland Mine Rehabilitation Group (CQMRG). The CQMRG was established 23 years ago with the aim of sharing informal knowledge related to practical aspects of rehabilitation in order to leave as positive a legacy as possible from mined land. This voluntary group of professionals also includes members from regulatory agencies and civil society. Within the dynamic regional mining environment, mine rehabilitation professionals benefit from sharing their informal knowledge.CQMRG is currently a group in transition. Mining boom and downturn cycles have exacerbated the loss of accumulated knowledge in the core CQMRG membership due to rapid changes in personnel at mines in the region. Additionally, some of the most experienced CQMRG-affiliated rehabilitation practitioners are approaching the end of their careers and want their valuable and less formal knowledge retained. This paper discusses the development of a research project that emerged in response to the anticipated loss of several decades’ worth of valuable knowledge as rehabilitation practitioners in CQMRG left the region or the workforce.CITATION:Unger, C J, Bond, C J, Baumgartl, T, Glenn, V C and Sabourenkov, P, 2016. ‘MRC-wiki’ – a mine rehabilitation and closure knowledge management tool for Central Queensland coalmine practitioners, in Proceedings Life-of-Mine 2016 Conference , pp 39–42 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By P D. Munro

On the occasion of the 14th Mill Operators’ Conference and marking 40 years since the first one was held in Mount Isa in 1978, it is fitting to review the history of the Conference and its development over that time.The first 10 Conferences were irregularly held at three to four year intervals, with 9 of these in regional centres of Australasia. It is only since 2012 that the Mill Operators’ Conference has become a regular biennial event, alternating with the MetPlant Conference.The number of people attending the Conference has more than doubled to 470 delegates at the 13th one in 2016. It has outgrown its regional beginnings.Papers presented to the previous Conferences have been analysed according to commodity, country of origin, technology and theme plus the affiliation of the authors to discern any trends that may assist in planning the future events.Suggestions are made as to how the AusIMM might wish to arrange its mineral processing/metallurgical conferences.Recent changes to the structure of the Conference providing a more meaningful experience for the delegates and increasing their interaction and involvement should be vigorously pursued.CITATION:Munro, P D, 2018. Mill Operators’ conferences – a 40-year retrospective and a vision for the future, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 5–14 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By S McKnight, L Koroznikova, J Begelhole

"This paper outlines a simple methodology for iron ore characterisation. Iron ores commonly contain a range of iron oxides with varying iron content along with generally minor quantities of lighter silicate gangue phases, giving rise to density variations. Companies tend to rely on heavy liquid separation (HLS) in the evaluation of samples arising from exploration, mining or metallurgical processes. Heavy suspension separation (HSS), a simple laboratory technique of density fractionation, employing suspensions of fine tungsten carbide (WC) particles in lithium heteropolytungstate (LST) solutions, can be used in the evaluation of iron ore.As part of Arrium Mining’s program to improve its knowledge of ore types being processed in two hematite ore beneficiation plants (OBP), metallurgical evaluation of hematite feed and geometallurgical evaluation for the OBPs has become a major focus.Metallurgical evaluation of the hematite ore ultra-fine size fraction, formally treated as waste but now upgraded by HSS, is a part of Arrium’s program to improve recovery.The HLS method for iron ore characterisation is not generally used as part of routine iron ore feed metallurgical evaluation due to the expense, toxicity and time-consuming nature of the technique. Results show that the HSS method for iron ore characterisation can achieve low-cost, low-toxic separation and can be used on-site to improve turnaround time of results (Begelhole, Jasper and Koroznikova, 2013).Arrium have applied this technique successfully for the past three years to progress process improvement for the two OBP as well as to assist Arrium’s on-site laboratory services, Bureau Veritas in Whyalla.The main objective of this program has been to further develop the HSS procedures using a low-toxicity, high specific gravity (SG) suspension; LST and WC as the dense medium for metallurgical evaluation of ultra-fines.A suspension of a particular density will separate iron ore into two products: a sink fraction (denser iron oxide – hydroxide particles) and float fraction (silicate – iron ore composite particles). A theoretical grade and mass recovery can be calculated, and a grade – mass recovery curve can be constructed for iron.Metallurgical evaluation of the plant feed ultra-fine size fractions are used to improve efficiency of an upgrading plant process. This type of characterisation can be used to prepare feed piles of known processing characteristics, or to benchmark the performance of the process against what can be theoretically achieved.CITATION:Koroznikova, L, Begelhole, J and McKnight, S, 2016. Characterisation of Low-grade Hematite Ore Ultra-fine Size Fraction Particles by Heavy Suspension, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 327–334 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

Young professionals are riding the current wave of high demand for their services and relatively little competition for placements. The attraction and retention of quality incumbents has therefore become a significant strategic issue for companies in our industry. Money is important, but poorly structured career development and lack of learning opportunities can discourage the highest paid professionals from being enthusiastic and striving for excellence. This will inevitably lead to the search for a new position. Important factors at play include the young professionalÆs lack of understanding of career pathways and poor quality, or lack of, structured on-the-job training and professional development. Too often young and not so young professionals are faced with the reality that fabulous looking (and paying) jobs can be quickly reduced to the monotony of repetitive tasks in an isolating environment. While it is the responsibility of the incumbent to manage their own career and professional development, without experience, how is anyone meant to understand the importance of their roles and the options for career development? Mentoring is therefore essential to the strategic plans of every organisation and the strategic plans of every professional. Mentors will accelerate learning, guide decision making and develop both competency and confidence as they share their experience, both technical and regarding the machinations of a particular discipline, within our industry. Mentors need not be from the same organisation as the mentee and in some cases this may be a distinct advantage. This paper discusses mentoring as an opportunity for young professionals and mentors to initiate and maintain a supportive relationship, the responsibility of management to get mentoring right and the responsibility of young professionals to demand the opportunity for professional development through mentoring.

Jan 1, 2006

Accurate geometric models of orebodies establish the framework for reliable mineral resource estimates that provide a basis for further exploration and mine planning, as well as for financial models that ultimately determine the economic viability of a deposit. Traditional, explicit geometric modelling techniques that are utilised for resource modelling by the general mining software packages, such as MineSight«, involve manually digitising interpreted ore outlines that must be carefully linked to create valid geometric solid models. An alternative, implicit modelling method, employed by LeapfrogTM software relies on a fast method of global interpolation, which offers several advantages over traditional modelling techniques. Although previous case studies have documented the relative efficiencies of the two approaches, the accuracy of the two methods has not been previously quantified and compared. This study quantifies the accuracy of solid models created using explicit and implicit methods, and compares the differences between the models. Solid models of the Doris Hinge vein gold deposit (located in the Hope Bay district, Nunavut, Canada) are constructed from preliminary and follow-up drilling data using both modelling techniques. The accuracies of the solid models generated using preliminary drilling data are determined by measuring the 3D distance between the surface of the models and the actual contact location defined by the follow-up drilling data. Additional comparisons based on volume, cross-sectional area and surface differences were made between both phase 1 solid models and solid models constructed from phase 2 drilling information. The overall results of this study find that the MineSight« and LeapfrogTM solid model accuracies are virtually the same, and that their volume, cross-sectional area, and surface differences are comparable. This study concludes that the implicit modelling technique generates accurate solid models that can be used in place of explicit models as ore shells for resource estimation in certain circumstances.

Jan 1, 2006

By J E. Wajon

This paper discusses the background, requirements, need and content of plans for management of drinking water self-supplied to mining-related operations, including construction camps, especially in remote areas of Western Australia. The paper discusses the importance of cooperation between regulators, the mine site operator and the consultant in preparing a plan fully compliant with the Australian Drinking Water Guidelines to protect the quality and safety of drinking water supplied to mine sites. The paper outlines some of the issues that need to be addressed in preparing a drinking water quality management plan, such as hazard identification, risk assessment, the multiple-barrier approach and the concept of critical control points. Data requirements, monitoring, incident management, training and reporting are also covered.CITATION:Wajon, J E, 2013. Drinking water quality management for mining operations in Western Australia, in Proceedings Water in Mining 2013 , pp 321-328 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By P Dowd, R Jeuken, C Xu

In Australian coalmines there are a number of coal quality parameters that are measured by analysing samples from boreholes. The data points are used to generate spatial models of these parameters, typically using inverse distance as an interpolation method. Numerous additional boreholes are drilled which have geophysical logs measured downhole but from which no coal quality samples are taken. Full suites of coal quality analyses are expensive and time consuming to drill and sample. If geophysical proxies for coal quality could be used, this would greatly improve the accuracy of the resource estimation without additional cost.This paper examines two of the most important coal quality parameters – ash and volatile matter – and assesses the results of a number of geostatistical interpolation methods. The aim is to improve the accuracy of the interpolated models. Auxiliary variables from geophysical logs are also trialled to improve the estimation.A multivariate analysis of ash, volatile matter and several auxiliary variables of a selected coal seam was undertaken in a spatial context, using variography. This was used to construct a model of co-regionalisation that relates all of the variables as manifestations of an underlying geological theme.The traditional inverse distance interpolation approach was compared to ordinary kriging, universal kriging, co-kriging, regression kriging and kriging with external drift approaches. The relative merits of the six interpolation methods were compared by removing all points, one at a time and estimating at the thus known location. The mean error and the root mean square error were evaluated as a measure of bias and precision.This paper demonstrates that there is significant opportunity to improve the estimations of coal quality when using kriging with external drift. For example, the results show that when using the depth of a sample as an external drift variable there is a significant improvement in the accuracy of estimation for volatile matter. Furthermore, when using borehole wireline density logs as an auxiliary variable for ash content, there is improvement in the estimation of the in situ ash. The underpinning reasons for this are discussed in the context of the underlying geology and the physical properties of the coal. These findings hold promise for utilising cheaper proxies for coal quality parameters to dramatically improve data density and the quality of estimations.CITATION:Jeuken, R, Xu, C and Dowd, P, 2017. Improving coal quality estimations using geostatistics and auxiliary variables, in Proceedings Tenth International Mining Geology Conference 2017, pp 157–168 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By P G. Doig

Recent drops in commodity prices and economic uncertainty have seen many businesses re-evaluate their operational expenditure to ensure mine profitability. The high capital and operational cost of truck and digger fleets has resulted in loading and hauling of material being a significant proportion of a mine’s expenses (Nel, Kizil and Knights, 2011), thus it is often one of the first areas to be considered for cost reduction. If an operation requires additional trucks to maintain or improve productivity, a robust justification is crucial due to the expenditure involved.Mining schedules form the basis of productivity and cost estimations for mining operations and therefore must have a significant level of confidence with regards to achievable quantities and rates. Traditionally, a mining schedule is produced without detailed consideration of the trucking capacity or requirements. Although some mine planning software incorporates haulage predictions into schedules, most cannot model the dynamic nature of dumping and haulage. Previous studies have shown that it is necessary to have detailed haulage analysis instead of the traditional mining block centroid to dump block centroid methods for more realistic mining schedules and cost estimation (Doig and Kizil, 2013).Recent developments in software have allowed the dynamic integration of haulage analysis with mining schedules. Engineers can now create mining schedules in conjunction with dumping schedules, allowing mining schedules to reflect the restrictions created by the number of available trucks, combined with dynamic consideration of available in-pit and out-of-pit dumping locations.A study has been completed producing a mining schedule in conjunction with a dumping schedule and haulage analysis. Multiple schedules were run with various haulage strategies (including minimising rehabilitation liability) and truck availability to identify the impacts on coal production, and hence revenue. A financial analysis was then completed where a net present value (NPV) was calculated for each scenario. The study showed that trucking shortfalls can significantly impact mining schedules and cost estimations, both in terms of cost as well as revenue lost when trucks cannot maintain forecast production rates, thus dumping schedules and haulage analysis should be completed simultaneously. If dumping and haulage is not considered when planning the mining schedule, a mining business is ignorant to the impacts trucking has on the mine production, closure risk and profitability.CITATION:Doig, P G, 2014. Value impacts of truck limited scheduling, in Proceedings Life-of-Mine 2014 , pp 513–524 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

Successful evaluation and exploitation of resources and reserves relies on the collection of high quality sample data. The quality of the sample data must be maintained through the application of a robust quality assurance and quality control (QAQC) program, including documentation of sampling procedures, training of sampling personnel and the regular monitoring of control samples. However, the application of QAQC programs in the minerals industry is often poor and the purpose misunderstood. It is all too common to have good quality control data collected, but no analysis work carried out until after drilling is completed. In a lengthy drill program, this can lead to problems not being discovered and corrected as they happen. Moreover, rectifying problems afterwards will be costly in terms of time and money, if not impossible. The consequences of poor quality sample data are many and include such effects as over- or underestimation of block grades, misclassification of ore and waste, and lower confidence in the resource/reserve models. The purpose of this paper is to highlight, using case studies, the importance of good QAQC practices to monitor the quality of sampling and laboratory sample preparation and analysis.

Mar 1, 2010

By M Gerards, M Steinberg, T Graham

The quality and quantity of Australia’s secondary deposits, which include tailings streams and tailings dams, are higher than most countries’ primary deposits. In addition, these secondary deposits have already been mined and processed, meaning that the recovery of high-grade product requires low capital and operating costs.The most widely used process for the recovery of these valuable fine and ultra-fine hematite iron particles is the wet high-intensity magnetic separation technique, originally developed by Dr Jones over 55 years ago. Many of the original machines are still working today.The aim of this paper is to demonstrate the capabilities in terms of grade and yield of using sophisticated magnetic separation modules. All results and figures are obtained from test work and design and engineering work with material from the Pilbara. In addition, consideration is given to dewatering of iron ore product and tailings.Two types of tailings have been identified for processing. Firstly, tailings that have already been deposited in a tailings storage facility, and secondly, live tailings streams from an existing wet iron ore beneficiation plant. In both cases, the technical and practical results are shown along with relevant flow sheets and plant layouts. Finally, this paper highlights the total predicted power and water consumption, capital requirements and projected operating expenses.The results show that the operating costs are significantly lower than the mining and processing operations that are required for an equivalent amount of iron ore. The recovery of iron depends on various factors but is within the 30–50 per cent range at an equivalent grade to the mainstream product. Another significant benefit is that the magnetic separation process is water positive, meaning that water is released rather than added in the process.The processing of the Pilbara’s secondary deposits will therefore result in an overall reduction in operating costs, an increase in product yield from a plant, extend the life-of-mine and offer environmental benefits by reducing the tailings footprint and water usage.The quality and quantity of Australia’s secondary iron ore deposits and tailings are such that many other countries would judge these as equivalent to primary deposits. Furthermore, these tailings are already mined, available and liberated to such an extent that the recovery of a valuable product is highly economical in terms of capital expenses and operating expenses.CITATION:Steinberg, M, Graham, T and Gerards, M, 2015. Recovery of iron ore fines and ultrafines from tailings by using wet high-intensity magnetic separation – JONES WHIMS, in Proceedings Iron Ore 2015, pp 191–196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By B W. Ham

The legacy of underground coal mining may be a land surface which, in parts, may be unstable in the long term. A case study analysis has been undertaken to explain some of the hazards and how the risk may be assessed and managed.The Ipswich Coal Measures were extensively mined with shallow underground workings, which now underlie a number of suburbs in the eastern side of the city of Ipswich in south eastern Queensland. The area was subject to underground mining from the 1840s to 1997. In general, the mines were small, family-owned operations that were restricted by complex geology, interactions with neighbouring operations and ownership of surface facilities. The oldest available mine plans date back to the late 1890s.The residents in these mining areas have a long history of unexpected mining subsidence events. A level of risk management for property owners has been implemented by the Ipswich City Council, which requires a mining subsidence risk assessment to be submitted as part of building applications for property development in the areas suspected of having mining subsidence risk. This discussion examines a series of generic subsidence events and how the risk may be assessed and managed and the hazard controlled.CITATION:Ham, B?W, 2014. The legacy of underground coal mining – mine subsidence: Ipswich coal measures case study, in Proceedings Life-of-Mine 2014 , pp 113–120 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By L P. Trout, D G. Reid

PanAust Limited (PanAust) has successfully constructed and commissioned two mining operations in Lao PDR over the past decade and undertaken major studies for three new mine developments. The management of potentially acid generating mine waste and tailings in close proximity of local communities sensitive to water discharge quality have been recurring themes that have confronted PanAust’s project study, development and operational teams. Further compounding challenges, such as the effects of intense annual tropical monsoonal conditions, staging of embankment raises and regular lifting of spillway structures, integrating mine waste and tailings management into production plans and ensuring the long term stability of structures, have been addressed by implementing leading practice management solutions.A recognition of the criticality of managing the substantial business risks associated with these crucial activities led to the early establishment of a governance structure to ensure that the highest standards are embraced for planning and execution. Importantly, these are guided and monitored by a panel of highly experienced and qualified international specialists reporting directly to PanAust’s Managing Director – the Tailings Independent Review Panel. The stewardship process has been effective in identifying potential shortcomings in management systems and has led to enhanced executive commitment to risk informed designs, assurance and overall process rigour.CITATION:Trout, L P and Reid, D G, 2018. PanAust Limited’s approach to mine waste and tailings stewardship, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 135–155 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By E Philippa, J Vitanza, C Hawtin, B Miller

B Miller , E Philippa , C Hawtin and J Vitanza

Mar 22, 2022

THE paper is principally eoncerncd with experimental work carried out the author whilst a number of the metallurgical staff at the Cockle Creek works. The metallurgical has been discussed sufficiently for the reader to follow the course of the experiments but the actual plant has only been described in so far as it effected metallurgical treatment, since the arrangement of such a smelter is a matter of common knowledge.The lead-roasting plant consisted of Godfrey roaster, Dwight-Lloyd maehines and Huntingdon-Heberlein pots. The usual treatment was in the Godfrey furnaces, followed by sintering in the Huntingdon- Heberlein pots. The paper is divided into two parts in the Godfrey furnaces and Huntingdon-Heberlein pots. An account of experiments on the utilization of the hood gases from the Huntingdon-Heberlein pots for acid making...

Jan 1, 1924

By S Agdaca

Leightons is the sole contractor at the Wahana Coal Mine Project (part of the Bayan Group), a multi-seam thermal deposit consisting of 13 coal seams with thicknesses ranging from 20 cm to 500 cm. The average dip of the deposit is 18 - 20°. However the deposit is heavily faulted in certain domains with anticlinal and synclinal structures present causing seams to dip up to 90°. Average thickness of coal inter-burdens range from less than 2 to 12 m. The minimum coal thickness being mined is 20 cm. Coal production is direct mine mouth feed and there is no coal processing plant currently used.Conventional blasting between the highly variable coal horizons in the early phases of the mine life was suboptimal from a production perspective. Drilling short holes with a reduced drill pattern, and on occasions with sloping benches, resulted in low drilling and explosives loading efficiency.A high frequency of small size blasts fired up to two times daily was required with each blast consisting of four up to five small blast areas. Each blast averaged approximately 36 000 bcm thus causing a low utilisation rate of the mining fleet from frequent blast delays and the inability to deploy larger Liebherr 9350 excavators on bench. It was identified that increasing the production targets required a more efficient drilling and blasting process. Furthermore, due to the highly variable nature of the deposit, the existing coal model was determined to not be able to accurately predict the coal seam location prior to blasthole drilling.In August 2009, Leighton Contractors Indonesia and Orica Mining Services with the full support of the Wahana team, initiated through seam blasting trials using electronic blasting systems. Further trials were conducted in November 2009. Trial evaluations indicated that the benefits from decreased lost time events due to blasting, an increased vertical advance rate per blast, and increased overall blast size could be attained while not damaging or diluting coal.Full-scale?through seam blasting has been ongoing since February 2010 for the upper eight coal seams to extract coal seam thicknesses ranging from 20 - 100 cm. This paper will discuss the parameters of the through seam blasting process in Wahana and the resulting benefits to the overall mine production.

Nov 8, 2011

The N3500 orebody is the northern continuation of the 3500 orebody at Xstrata Copper's Enterprise Mine and occurs at a depth of 1.3 to 1.8 km. At the nearby S3500 orebody, extreme deformation was observed in access drives where there was a high number of bedding planes per metre combined with either graphite or talc infill. The observed failure mechanism was largely controlled by the geometry of the inclined bedding submitted to high horizontal stresses. Due to the anisotropic strength and deformation behaviour of the shale rock mass, traditional isotropic methods of geomechanical property estimation based upon GSI are not appropriate. A numerical modelling approach, based upon the distinct element codes UDEC (2D) and 3DEC (3D), has been developed to accurately simulate the failure mechanisms and deformation observed in the initial infrastructure surrounding the N3500 orebody.

Nov 25, 2010

By R Williams, M Baxter, D Zink, R Cunningham

The purpose of this paper is to discuss the efficient operation of a tailings dewatering circuit comprising a thickener and filter press through proper control and automation. It is common to see thickeners and filter press circuits each with their own control systems. This can cause multiple issues when trying to increase efficiency and reliability of the tailings management process. By automating the thickener and filter press controls, you are eliminating any delays and inconsistencies caused by human error and process variations. When done properly the system can maintain a consistent product as the feed characteristics change. Previously, operators would have to monitor the process parameters and adjust the system accordingly. This can now be accomplished using state of the art process control equipment that continuously monitors and adjusts critical variables using Programmable Logic Controllers (PLC) and Proportional Integral Derivative (PID) loops. The paper will detail the control theory used to maintain these systems, highlight other benefits of having a fully integrated plant such as predictive maintenance and remote diagnostics as well as present examples of how these have been implemented in field examples.CITATION:Baxter, M, Cunningham, R, Williams, R and Zink, D, 2018. Tailings process optimisation through automation and controls integration, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 416–421 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By P Donecker

Like all chains, iron ore values chains are only as strong as their weakest link, which in ore processing is often the humble chute. While mechanically the simplest element in the iron ore flow sheet, chutes are often the most problematic and regularly the major cause of unscheduled downtime. Chute designs have remained static for decades, despite the extra demands being placed on them by grade reduction, which impacts chutes in three ways viz: 1. Higher volumetric rates as infeed increases to meet production targets. 2. Higher moisture content as mining goes below water table. 3. Stickier properties as the dilution phase is often clay based. While there is no shortage of ideas and the geometry options are infinite, the fact is that chute design has not kept pace with grade decline and has remained essentially unchanged. One reason cited for this lack of innovation is the difficulty evaluating and de-risking designs. While the power of computers running Discrete Element Method (DEM) models has advanced, the models themselves still need to be ‘calibrated’ with the dynamic properties of the ore. Flow properties commonly measured for bin design are useful for static situations only and were never intended to predict dynamic behaviour as in chutes, a critical qualification lost in the mists of time. So while they always produce a colourful and reassuring animation, DEM models informed by static ore properties often result in wildly inaccurate real world predictions. Responding to this low success rate, many operators are now utilising physical modelling to help reduce risk and avoid the consequences of having an underperforming chute in their value chain. Physical testing, in a dimensionless scale-down of the proposed system (bulk material and chute geometry), addresses the shortcoming of mathematical models designs and when used in combination with DEM is the best option. In the ideal world, the focus of chute modelling should be innovative design concepts aimed at addressing future needs, however in reality the focus is nearly always on modifications to installed chutes that are underperforming even today. This situation can be traced back to design procedures which if informed at all, are based static ore properties. As an industry, we need to break this cycle and become more proactive, which means addressing flaws in the current design process. In 30 years of providing modelling support to the industry, I have looking at hundreds of underperforming chutes in the iron ore industry. This practical experience has led to a unique and unbiased perspective on chute design and their performance in the real world. The knowledge presented in this paper can not only be used to help avoid baked-in problems now, but also help guide and evaluate designs so we can deal with the challenges of our low-grade future.

Sep 18, 2023

By I M. Platten, Y Xie

Sampling protocols that are designed to suit the mineralisation style will result in a reduction of the nugget effect and hence resource risk. The a priori need for all sampling programs is the effective characterisation of the mineralisation type(s) to support optimisation. This requires a program of sampling for sampling followed by holistic characterisation. At each end of the coarse-gold to fine-gold spectrum, the samplability of a deposit ranges from relatively simple for fine-grained disseminated gold particles, through to extremely difficult for coarse nuggety mineralisation. Many deposits contain a proportion of both particle size types. The proportion and size of coarse gold particles has a direct impact on the effectiveness of sampling, where coarser particles will require larger samples and more specialised protocols. The nature of mineralisation geology/mineralogy and associated gold particle sizing can only be determined by sampling to facilitate optimised protocols. Mineralogical studies, focusing on particle size, particle clustering and distribution in host minerals, are required as part of wider paragenetic and metallurgical investigations. This paper discusses the role of mineralogical studies in the characterisation of gold ores for sampling optimisation through a series of case studies.

Jan 1, 2008