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Sluice box operating practices in Papua New Guinea (PNG), and published work on sluice boxes are briefly reviewed. Some recent work on sediment entrainment mechanisms occurring in sluice boxes have also been described. In the light of this information, some drawbacks in the commonly adopted sluice box operating practices in PNG, and ways of overcoming them, are also highlighted.

Jan 1, 1991

By G P. Bates

The rationale for the design of the Emergency Egress (escape andentrapment) strategy for one underground metal mine has beenpreviously described (Brake, 1999). Two of the key conclusionsfor this mine, which is equipped with 30 minute oxygen-generating self-contained self-rescuers (SCSR), were the need to ensure no person is ever more than 750 m from an emergency refuge station (ERS) and that it could take up to eight hours to rescue workers from undergroundå. These conclusions were based on a number of considerations including the non-availability of a credible, æpersonalÆ entrapment procedure at the workplace, the duration of self-contained self-rescuers when used for travel, the need for rapid æclearingÆ of mine personnel to effectively and safely target mine search and rescue resources and the maximum time to either put a fire out, or to rescue affected personnel. As there is no Australian standard for refuge stationsç (or for self-rescuers), this paper follows with guidelines for the location and specification of both fixed (permanent) and relocatable Emergency Refuge Stations (ERSs) that may be applicable to other underground Australian metal mines.

Jan 1, 1999

By J Hadjigeorgiou, T R. Stacey

A ground support system is a combination of individual reinforcement and surface support elements that work together to retain and contain the rock mass. The various elements are subjected to external loads and to interactive loading between individual ground support system components. This paper focuses on the challenges in determining the capacity and behaviour of mesh, recognizing that installed mesh can be subjected to several loading mechanisms. Field observations from underground hard rock mines demonstrate that there are multiple types of damage and modes of failure of mesh. However, these are difficult to reproduce in a laboratory environment. A critical review has shown that existing mesh laboratory testing rigs reproduce very limited loading conditions that may not be representative of underground conditions. This has significant implications in quantifying and extrapolating the performance of mesh to ground conditions. CITATION:Hadjigeorgiou, J and Stacey, T R, 2018. Challenges in determining the capacity of mesh, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 280–290 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By J Langhans, Y Choi, Q Wang, J Y. Baron, P Kondos

Barrick has successfully developed the thiosulfate leaching process to treat sulfidic high preg-robbing ores. The process was developed through rigorous bench test programs and proved in pilot campaigns and demo plant operations. The process uses calcium thiosulfate as a leaching reagent, resin for gold recovery with sulfite/trithionate elution and reverse osmosis as a mean of reagent recovery. The thiosulfate leaching plant is under construction as a brownfield project and the start-up is planned in 2014 at Goldstrike, Nevada, USA, one of BarrickÆs operations.CITATION:Choi, Y, Baron, J Y, Wang, Q, Langhans, J and Kondos, P, 2013. Thiosulfate processing - from lab curiosity to commercial application, in Proceedings World Gold 2013 , pp 45-50 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By F Sinaga, E Widijanto

PT Freeport IndonesiaÆs Deep Ore Zone (DOZ) mine is the new underground block caving mine within the East Ertsberg Skarn System (EESS) which started production in mid-2000. The DOZ will produce 25 000 tpd using mechanised block cave mining method and will be the fourth underground mine opened within the EESS deposit. A review of the DOZ extraction bolting design was conducted in November 2000. The aim of this review was to re-evaluate the effectiveness of the current design in relation to bolt length and spacing and to challenge some questions about the technical background of the design. For instance, the influence of the rock condition on the design. To review this bolting design, several books and papers are reviewed and several experienced people have been contacted to give their opinion. The methodology used for this review is:reviewing the technical background of current design; collecting ideas and alternatives; collecting data from books and personal communication and conducting analysis; and conclusion and proposed design.

Jan 1, 2002

Adsorption of Starch on Kaolinite Surfaces

Sep 13, 2010

By K Blay, C McCamley, P Petrucci

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

Aug 29, 2018

By O Aydan, R Ulusay

Blasting is the most commonly used excavation technique in mining and civil engineering applications. Blasting induces strong ground motions and fracturing of rock mass in rock excavations. Particularly, high ground motions may also induce some instability problems of rock mass and structures nearby. Furthermore, it may cause some environmental problems due to noise as well as vibrations of structures near the populated areas. Furthermore, flyrocks is another major issue for the safety of people and damage to machinery and equipments when blasting is employed. In this study, the authors explore the ways how to estimate the ground motions as a function of distance, amount of explosive, number of holes. The ground motions were measured by stand-alone accelerometers developed by the first author and some empirical relations are developed. The effect of ground motions on the instability issues of benches such as sliding, toppling and rockfalls were investigated. Furthermore, the flyrock issue is investigated and some empirical relations to estimate the maximum distance of flyrocks from the blasting relations are compared and discussed. CITATION:Aydan, O and Ulusay, R, 2018. The ground motions induced by blasting in open pit lignite mines and its environmental effects, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 142–151 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

Upgrading and Removing Phosphorus from Low-Grade and High Phosphorus Containing Iron Ores

Sep 13, 2010

By E Rubio, N Morales

Currently, mine plans are optimised by using several criteria as objective functions, like profit, life-of-mine, concentration of some pollutants, mining costs, confidence level or ore resources, with consideration of constraints related to production rates, plant capacities and grades. Whilst this approach is successful in terms of producing high value production schedules, it uses a static opening sequence of the drawpoints and therefore the optimisation is made within the level of freedom left by the original opening schedule, and as a result it is far from the true optimal value of the project. This paper presents a model to optimise the sequence of drawpoint opening over a given time horizon. The emphasis is in the precedence constraints that are required to produce meaningful operational sequences considering the exploitation method (panel or block caving), physics considerations and logical rules. Further on, while it applies the standard approach of maximising net present value (NPV), it considers other targets for optimisation, like the robustness and constructability of the plans. Finally, it applies the model to real data to obtain feasible plans by means of this model. The first tests were done varying the production capacity of the mine.

Sep 26, 2011

By J H. Park, R R. Kim, H S. Park, H J. Kim

This study focuses on the recovery of valuable metals, specifically silver (Ag) and palladium (Pd), from copper-containing sludge (with copper content less than 20 per cent) generated during PCB processing and from spent petrochemical catalysts used in vapour decomposition during oil refining processes. The present results indicate that an increase in the mixing ratio of alumina-based spent catalyst leads to a decrease in the recovery rate of Ag and Pd. The recovery rates for Ag and Pd range from 84 per cent to 96 per cent and 80 per cent to 98 per cent, respectively. This trend is attributed to the increased emulsification of copper droplets containing Ag and Pd in the slag. The emulsification is caused by the decrease in the settling velocity of the copper droplets due to the increased viscosity of the slag as well as by the decrease in the slag-metal interfacial tension due to an increase in sulfur content at higher mixing ratio of spent catalyst.

Jun 19, 2024

By P C. Hagan, J Chen, S Saydam

Fully grouted cable bolts have been used in underground mining industry for more than 40 years and are becoming more and more popular especially when severe geological conditions are encountered, such as high stresses and large cross-section excavations. The axial performance of cable bolts are mainly relied on the load transfer process between the cables themselves and surrounding rock masses via grout annulus. Therefore, the selected grouts play a significant role in determining the reinforcement quality for underground openings. In order to better understand the mechanical properties of Stratabinder HP grout, which is one type of cementitious grouts commonly used in Australian underground coalmines, plenty of unconfined compressive tests are conducted on it. Following diverse standards, two different kinds of samples are prepared and tested with the w/c ratio ranging from 0.35 to 0.45. During the test important mechanical properties including uniaxial compressive strength (UCS) values, Young’s modulus, Poisson’s ratios and so forth are recorded. Based on experimental results, the effect of w/c ratio on the mechanical properties of Stratabinder HP grout is studied. Beyond that, influences of sample size on the failure mode, peak strength as well as residual strength of this kind of grout are summarised and analysed.CITATION:Chen, J, Hagan, P C and Saydam, S, 2014. Mechanical properties of cementitious grout serving in fully grouted cable bolting systems, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 269–276 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By C N. Hatton, K Ward

Tailings operations are inherently reactive as operations personnel continuously contend with a concentrator reject feed (tailings) transient in physical and engineering properties, which places a constant constraint on capital and operational spending. It requires a unique skill set to manage the prescribed distribution of tailings under unenviable conditions. Enter the tailings operator, an oftenundervalued commodity and untapped resource that can provide benefits beyond the rigors of dayto- day operational support. Experience consistently demonstrates that skilled and committed operators can serve a vital function in the safe construction of a tailings storage facility. It takes a village to raise a tailings dam. An important part of this process is establishing a culture of operational accountability and ownership. Operator development training is nothing new. However, we find that many of the intrinsic operator skills are left unexploited, and an operator's experiential knowledge base and creativity are commonly overlooked and underutilized. With proper training and guidance, these skills can be harnessed, contributing to safe dam operations. Operator engagement, when properly facilitated, provides tangible benefits ranging from improved tailings engineering properties to reduced closure costs. One important benefit is helping transitioning tailings management from reactive to proactive. There are many processes involved in the reactive to proactive transition process. One element of that process includes engaging operators in the tailings management process and facilitating legacy ownership. The core of operational legacy ownership is measured and described using five-stage operator engagement rubrics. Levels of operator engagement are presented with a description of the incremental benefits of each stage. An important part of legacy engagement is providing the tools to operators necessary for managing the tailings. Therefore, the approach identifies specific methods used by operations personnel to control tailings distribution and in-place properties. The end goal of leveraging operator engagement is to facilitate committed ownership and transition tailings management from an inefficient, reactive process to an improved, cost-effective, proactive practice.

Jul 1, 2021

By X Yang

White phosphorus (P4) is a critical element in industry, but its current production from phosphate rock using the carbothermal reduction method raises significant environmental and health concerns. This pressing issue necessitates the development of new technologies that facilitate the sustainable production of P4. In response, my team is actively developing an innovative, coke-free approach for white phosphorus production. This method involves the dissolution of phosphate rock in molten CaCl2, followed by the extraction of P4 through electrochemistry at relatively low temperatures. Moreover, this approach has the potential to utilise phosphate-bearing solid wastes as raw materials, further enhancing its environmental benefits. By employing this cutting-edge technique, we aim to revolutionise the phosphorus chemical industry towards greener and more sustainable practices. This paper provides evidence of the feasibility and effectiveness of our proposed approach.

Aug 21, 2024

By M Dohm, L Pretorius

This paper provides a brief historical background to the approximately 12-year project that led to the revision of rope selection factors in the South African regulations, thus providing the ability to hoist economical payloads from single lift ultra-deep shafts. The efforts over the past 20 years have led to the revision of the legislation pertaining to rope selection factors, the redesign of rope constructions to meet the required duties associated with ultra-deep shafts, codes of practice for the design, operation and maintenance of winding plants, and a code of practice for the condition assessment of winder ropes. As a consequence the Moab Khotsong ultra-deep hoisting system could be developed and installed, with the assurance of predictable performance. Access to deep orebodies by means of single lift, ultra-deep shafts has a critical impact on the life cycle costs and efficiencies of ultra-deep mining complexes. A brief description of the main components of the hoisting system at Moab Khotsong is presented. An in-depth review of the development process applied to ensure a stable, safe and cost-effective rope construction for the ultra-deep Moab Khotsong shaft follows. The paper concludes with an overview of the experiences gained during the installation and commissioning phases of the winder, as well as operational and maintenance issues.

Jan 1, 2005

By S R. Green, G D. Corder

The legacy issues from mining can, and have often, extended well beyond the closure of operations. However, conventional cost-benefit analysis provides little incentive to implement initiatives at the project development stages of a new mining project as the costs that will be incurred towards the end of the mine life, 20 years or longer, appear minor in net present value (NPV) terms. This analysis can be misleading as the true costs of managing post-mining land can continue for many years, or decades, after mining ceases and any resulting unfavourable legacy issues can delay or prevent government permits or licences to develop new resources. Proper upfront planning is critical for implementing successful rehabilitation and closure strategies. The investment in this planning needs to be done in a structured and rigorous manner taking into consideration the long-term and broad benefits of sustainable land uses after mine closure. The advantages of such an approach could include the streamlining of regulatory approvals by early advice to the regulator of identified issues and responses to those issues, and clear evidence that a strong social licence to operate ethic with local, regional and national benefits is included in the decision-making process. This paper investigates the potential closure options for two case studies at the early stages of project development - concept and prefeasibility. By using a sustainability framework that can identify opportunities and risks, prospective initiatives that deliver enhanced environmental, community and social benefits will be compared with compliance-orientated approaches. This comparison is made across the Five Capitals Sustainability Model - natural, human, social, manufactured and financial. The results of this analysis demonstrate that upfront planning during project development and due care and effort during the life of the working mine will reduce the risks of long-term detrimental legacy issues. This will ultimately benefit the mine operator, the local community and the state.CITATION:Corder, G D and Green, S R, 2012. Using a sustainability assessment framework to achieve enhanced legacy outcomes, in Proceedings Life-of-Mine 2012 , pp 311-318 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

In the Broken Hill South mine tile practice of issuing to the miner a quantity of fuse and a box of caps from which he made up the "rods" required for a particular blast, has been abandoned. Instead, capping stations have been established, and the miner can now obtain, from the magazines, fuses cut to accurate lengths with the detonators attached.Various types of fuse-cutting machines and crimping devices are available, but only those used by the Broken Hill South Mine Ltd. are described in this paper.The fuse-cutting machine, designed by the engineering staff, is an electrically driven unit fitted with a gear box for the purpose of adjusting the rate at which the fuse is fed to the cutting device, thereby enabling fuses of various lengths to be accurately severed from the main coil of fuse.The machine in question is designed to cut 4, 6, and 8-ft. fuses, but no difficulty should be experienced in designing a machine to cut fuses to any required lengths.

Jan 1, 1932

The following notes apply more especially to the purchase of silverlead ores produced in the neighbourhood of Zeehan and Dundas; for it is this class of ore that is principally mined in those parts, and which creates competition among the ore buyers.In the early days of this field, most of the ore passed through the hands of the first buyer who had sufficient enterprise to establish himself at Zeehan but in more recent times, competition has been so keen that there are generally three or four buyers tendering. lf the output was large this would not matter so much from the buyers' point of view but when we consider that the output of the field is only some 1,650 tons per month, and that of this 70 odd tons are produced by the Western and Montana mines, aud being sent home for realization, is withdrawn from local purchasers, there is really not enough for four buyers, especially at the present exorbitant prices they pay the miners.Some of the mines have a fixed sampling day, on which it is tacitly understood that the ore buyers will attend. Others, such as Grubb's Silver Mining Oompany, No-Liability, send round a printed reminder, stating the quantity of ore, and the date of sampling.

By Baafi EY

Deposits of gold, silver and other precious metals often display a high variability of grade values, usually a very low average metal content and are frequently not easy to sample reliably. The characteristics, together with the volatility of precious metal prices, make evaluations of precious metal deposits extremely difficult to make. Geostatistical estimation techniques can be used to make grade estimates of precious metals and to assess the reliability of these estimates. Two case studies are presented.

Jan 1, 1987

By T P. Tafirenyika, K C. Corin, C T. O’Connor

There is a growing demand for copper driven by its applications in renewable energy and electric vehicles. Sulfide ores are an important source of copper. Flotation is a critical front-end process used to remove gangue minerals and concentrate the copper minerals. The electrochemical activity of sulfide minerals contributes to their overall activity in the flotation pulp. The mineral rest potential dictates how collectors interact with the mineral surface, and hence ultimately on the flotation response. Dissolved oxygen, (DO), pH, redox potential (Eh) and water composition and ionic strength are also significant in controlling flotation performance. The aim of this investigation was to determine the influence of the electrochemical environment both during milling and flotation on the flotation behaviour of bornite and chalcocite. For this investigation, the interactions of collector with bornite and chalcocite were studied using synthetic plant water (SPW1) and deionised water (DIW) at 5 different pH levels. Sodium isobutyl xanthate (SIBX) was used both in microflotation, collector adsorption and zeta potential tests.

Aug 24, 2022