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By Alexander RB, Hollis AJ

The magnitude of the payloads carried by mine haul trucks can have a strong influence on the mine production rates and costs. Consequently control of truck payloads is highly desirable, but in many mines the unavailability of means for measuring payloads reliably, accurately and easily has resulted in a low level of control over truck payloads. Consideration is given to two techniques which are applicable to the measurement of payloads carried by mine haul trucks, namely truck weighing and direct measurement of payloads with truck based systems. Accuracy assessments for two types of truck weighing platforms and two prototype truck based direct payload measurement systems are provided. Results show that weighing platforms based on hydraulic components have proved inadequate, while strain gauge type weighing platforms can estimate payloads to within 2% of true payload when installed, maintained and used correctly. The assessment of the two prototype truck based direct payload measurement systems shows that a high proportion of payloads were estimated to within 5% of the payloads derived from accurate weighing platforms and that these systems appear to have the potential to provide convenient and accurate measurement of payloads. This should enable payloads to be much better controlled than has been possible to date. Predictions of the effect of payloads on production rates and some components of truck haulage costs are possible and some typical results are presented. Accurate prediction of the effect of payloads are not yet possible for some major components of truck haulage costs.

Jan 1, 1986

There are a number of mineral processing operations which produce at some point a stream of hot particulates. At today's energy prices it becomes important to recover the energy held in the hot particulates. Sometimes it is convenient to use gas, e.g. in air pre- heating, and this will be appropriate in some circumstances. There are cases where it would be very useful if energy in the hot processed particles could be exchanged to the cold feed solids. This can be achieved within appropriate limitations by countercurrent heat exchangers comprised of parallel channels which contain, alternately, fluidized solids of 'hot' and 'cold' streams respectively. A pilot- plant has been built. Some calculations relating to industrial application will be Presented.

Jan 1, 1981

By J Li, A McFarlane, J Yu, L L. Kuhar, R Meakin, N Chapman

"Column leach tests are used frequently to predict recoveries and reagent consumption for nickel laterite heap leaches. These column leaches often run for more than 100 days and therefore require long-term monitoring and data analysis to achieve the desired information. To minimise the cost and time required to obtain relevant information for nickel laterite heap leaching, we have developed a small-scale hydrogeometallurgical laboratory test to serve as a proxy to column, and by inference, heap leaching. In excess of 50 leach tests were conducted using four different small-scale proxy and column leach tests to compare predicted nickel recoveries, acid consumption and leach kinetics and to determine whether insight into potential scale-up effects can be obtained. The most promising proxy test was identified and we achieved a statistically significant recovery and acid consumption correlations between this test and the column leach tests. The accuracy of the small-scale tests was confirmed by column tests run on new laterite ores. This geometallurgical proxy could be of use for the population of block models and process selection during the mine planning phase or for optimisation and control during processing.CITATION:Li, J, Kuhar, L L, Meakin, R, Chapman, N, McFarlane, A and Yu, J, 2016. A Geometallurgical Proxy for Nickel Laterite Heap Leaching, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 335–340 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By I M. Platten, Y Xie

Narrow vein gold mineralisation generally contains both fine (<100 ¦m) and coarse (>100 ¦m) gold particles. The in situ size and shape, deportment, distribution and abundance of the particles controls deposit sampling characteristics, grade distribution and metallurgical properties. Particles can range from individual disseminated grains, clusters of particles and masses above 1 cm in size. 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 very coarse particles. Deposits generally show a background grade of mineralisation dominated by disseminated fine gold particles. Drilling will resolve the background grade well, though is likely to considerably understate the grade related to the coarser gold particles. Gold mineralogy has a significant impact on metallurgy, with key factors affecting recovery being particle size, deportment, liberation parameters and silver content of gold minerals. For coarse gold particles the focus should be on liberation and the early removal of the particles from the mill circuit by gravity concentrators and gold traps. Finer particles will require more grinding to liberate prior to flotation or cyanide extraction. The determination of gold particle sizing is thus required to minimise evaluation and geometallurgical uncertainty and lower project risk.

Jan 1, 2008

By R P. Varden

This paper looks at the design of the Bentayga raisebore with subsequent back analysis using a LiDAR survey. A search for LiDAR raisebore assessment publications shows little work has been done on this subject. The paper examines the empirical design and RS2 modelling assessment with the bored condition. The high resolution of the LiDAR enabled mapping of weak structures that were located on the geotechnical investigation hole the orientations of which could not be determined. In addition, the scan showed were water ingress was occurring, potential stress overbreak and structural controls on stability. The LiDAR results were able to confirm no additional support work such as a shotcrete liner is necessary. The LiDAR results have been analysed in one metre increments as volume of overbreak against the empirical stability criteria (McCracken & Stacey 1989). The future use of LiDAR mapping over a range of rock mass conditions will provide quantification of the established empirical assessment improving its reliability. It is also a useful and accurate tool to monitor long term stability of a raisebore due to stress change or ore pass due to wear.

Mar 15, 2021

IN this paper an attempt is made to describe the sluicing operations on the tin fields of north-eastern Tasmania. No claim is made to completeness, for much of the ground has already been covered, and nothing is to be gained by needless repetition. On this account some portions of the subject have obviously received but scanty attention in order that others may be rather more fully dealt with; for instance, figures referring to the accuracy of various methods of valuing alluvial deposits, particulars of efficiencies, and water duties on both overburden and drift; also, the system of recording water distribution, &c.The plans of the tin-streaming shed, sluice and feed·race, and overburden tail-race represent types of the most modern design.The principal alluvial deposits being worked at the present time are situated either in the ancient or modern bed of the Ringarooma river or its tributaries. This river flowed in a north-easterly direction, receiving numerous tributaries on either bank, and finally emptying into Boobyalla harbour. The most important of these tributaries, from a mining point of view, are the Cascade, Main creek, Weld and Frome rivers (which unite just before joining the modern Ringarooma), Wyniford river, and Bradshaw's...

Jan 1, 1911

By T Rohde, P Defferrard

In 2010 a store and release cover (the cover) was constructed on the south waste rock dump (SWRD) at Century mine. This also included aerial seeding of province native trees and shrub seeds. The purpose of the cover is to reduce percolation into the potentially acid-forming (PAF) waste rock by maintaining a compacted reduced permeability layer (RPL) at near-saturated conditions. This is achieved by overlaying the RPL with a 1.5 to 2 m thickness of soil-mulch. The soil-mulch has a hummocky final surface that captures rainfall, so it does not runoff, allowing it in part to infiltrate, with excess water removed by evaporation and transpiration. The RPL is the trafficked surface of the SWRD.The unsaturated behaviour of the cover is being monitored by instrumentation including volumetric water content and matric suction sensors and a weather station capable of estimating evapotranspiration. The instrumentation allows for direct measurement of infiltration into the cover, storage of rainfall, percolation through the base of the cover and in situ soil water characteristic curves (SWCC).The key functions used to describe the unsaturated behaviour of the cover materials is the SWCC and the unsaturated hydraulic conductivity function. The SWCC is a plot of soil water versus soil suction. It provides the loci of moisture states of a soil from the saturated to the dry state.The paper presents the results of five years of monitoring. It shows that total infiltration into the top of the SWRD was about 1.6 – 3.7% of cumulative rainfall over five years, with most of the infiltration going into storage within the cover. Runoff from the top of the dump is not allowed therefore, the remaining 95% of the total rainfall was lost to evaporation or as lateral flow when infiltration reached the RPL. The paper presents some simple analyses of the wetting by rainfall infiltration of the cover, leading to breakthrough at the base. Field data are used to support the analyses.Presentation of the SWRD water balance is also included in the paper using SVFLUX™GE which is a finite element model that simulates water transport through a saturated or unsaturated medium.CITATION:Defferrard, P and Rohde, T, 2018. Five years of cover performance monitoring and modelling for a store and release cover at Century Mine, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 179–189 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By M I. Pownceby

High temperature roasting studies on chrome-spinel contaminated ilmenite concentrates showed that sulfur, introduced through a sulfidising roast treatment, selectively reacted with the chromium in the spinels. The roast treatments were carried out in a laboratory scale rotating drum kiln using a standard Becher-style heating profile (10 h, 1075ºC), char as the reductant, and variable amounts of added elemental sulfur (0 - 3 wt per cent).After roasting, bronze-coloured grains were visible representing chrome-spinels that had undergone selective sulfidisation. SEM imaging of the products showed that sulfur was preferentially concentrated in ~5 - 15 µm thick rims fully enclosing the chrome-spinel grains. The sulfur-rich rims became a sink for manganese (Mn) from the ilmenite resulting in the rims being rich in Cr-Mn-Fe-sulfides. Quantitative electron probe microanalysis of phases present within the rims identified two sulfide phases. The first sulfur-phase (S-phase) was low in Mn (1 - 3 wt per cent) and high in Fe, Cr and S, while the second S-phase was considerably higher in Mn (30 - 35 wt per cent Mn) and lower in Fe and Cr. The dramatic change in the composition of the chrome spinels after sulfidisation is likely to significantly alter their physical properties (eg hydrophobicity, conductivity, etc). This should make their physical separation from the ilmenite potentially easier than roasting/magnetic separation methods.

Oct 5, 2011

By U König

The use of high speed detectors made X-ray diffraction (XRD) an important tool for quality and process control in the mining industries. Besides knowledge about the mineralogy of a sample it provides useful information in terms of quantification of the crystalline phases and the amorphous content. Cluster analysis of XRD data can facilitate multi-dimensional mapping of ore deposits and drill cores, identifying regions of favourable mineral compositions. The studies of this paper demonstrate how XRD and data clustering can be used for grade control, process optimisation and quality control of iron ores and iron ore sinters. These new developments have an enormous potential as an inexpensive, reliable tool, useful in the characterisation of iron and sinter materials implemented in an industrial environment.

Jul 11, 2011

By J Pan

In this paper, the technology of producing fluxed pellets by using hydrated lime as binder instead of bentonite was carried out. The properties of the two types green balls (0.8 per cent bentonite and 2.0 per cent hydrated lime) were as follows: drop numbers of 4.8 - 5.0 times/0.5 m, compressive strength of 19.7 - 24.2 N/pellet and thermal shock temperature of 280° - 385°, respectively, under the same conditions of 1.5 per cent coke, 1.45 basicity and balling at 8.5 per cent moisture for 13 min in disc pelletiser. Comparing with bentonite as binder, the compressive strength of fired pellets with hydrated lime is elevated by 13.8 per cent and climbs up to 3113 N/pellet under the following conditions: preheating at 1050°C for ten minutes and fi ring at 1300°C for 15 min. In the mean time, the hydrated lime also improves the metallurgical performance of fired pellets. The reduction index was enhanced from 68.6 - 70.6 per cent, RDI+3.15+ increased from 90.1 to 98.8 per cent and reduction swelling index dropped from 22.4 - 7.4 per cent, respectively. The mineral compositions and microstructure of fi red pellets shows that the fired pellets containing 2.0 per cent possess more calcium ferrite and magnesium ferrite and compact microstructure, leading to the higher compressive strength.

Jul 11, 2011

Since the 1950's drilling has been rapidly mechanised. First from hand held drills with air legs to pneumatic jumbos, then to more effective hydraulic jumbos. Development of underground drilling equipment naturally could not have stopped here. Hydraulic drilling saw an improvement in drilling capacity and efficiency after the introduction of second generation drifters in the early 1980's. Also in the early 1980's a few equipment suppliers started to study how to improve the efficiency in operating the rigs. The first computerised rigs for tunnelling were delivered to work sites in mid 1980's. At the same time a few computerised longhole drills started drilling in mines.

Jan 1, 1988

By Beamish B. B

In this study, a systematic examination of the scale and variety of micro-structures in coal using Scanning Electron Microscopy (SEM) has been carried out, using coal samples of differing stages of coalification from the Bowen Basin and New Zealand. SEM provides detail of various micro-structural features and shows that a variety of micron-sized fractures and cavities are present in coals. These are differentiated into three pore types: fracture porosity, phyteral porosity and matrix porosity. Fracture porosity is generally associated with bright coals (although it has been shown that micro-fractures are present in maceral fragments from the dull coal layers). Characteristically the macro- and micro- fractures form a continuous structural fabric through the bright coal layers and thus make a significant contribution to overall permeability. The macro- and micro-fractures appear to have been formed during the process of coalification rather than being formed due to shrinkage during methane extraction, as most of them are infilled with secondary minerals. In contrast, phyteral and matrix porosity is associated with the dull coal layers that are composed of plant fragments or a heterogeneous mixture of macerals. Like the macro- and micro-fractures, the continuity of the observed cavities suggest that these too are a significant contribution to overall permeability, and therefore play a major role in the transmissibility of methane at a level between diffusion at the micropore level and laminar flow at the macro-fracture level. Due to different spacing, orientation and persistence of individual fractures and cavities, the rate of methane transmissibility through a coalseam will vary according to coal rank, coal type and the organic precursors from which the coal was derived. This is important as a knowledge of the micro-structure system and its relationship to coal type and coal rank, plays an important consideration in: a) gas drainage modelling, b) enhancing permeability by inducing fractures and c) predicting the occurrence of outbursts.

Jan 1, 1991

One of the responsibilities of the Melbourne and Metropolitan Board of Works is to provide a sewerage system for the metropolis of Melbourne which now contains over 2.5 million people. In providing this sewerage system it was necessary for the Board to embark on a large tunnelling programme some 20 years ago. As a result of this extensive tunnel construction programme, tunnel boring machines and shaft sinking methods have been developed to cope with the soft ground and soft to medium rock found in the southern and eastern areas of Melbourne where the majority of the recent tunnelling has been carried out. While in the last few years radical changes in construction methods have not been made, development has continued and improvements have been made, which have enabled the Board to extend the limits of the ground conditions in which it can efficiently construct shafts and also tunnels with boring Machines.

Jan 1, 1976

The sinking of the new No. 3 Shaft being mainly concerned with providing for the continuation of mining operations north of the existing workings, requirements for the shaft and haulage equipment were assessed, having in mind the anticipated needs of the Company in future years, the .available knowledge and probable future trends of the orebody, and also that the shaft would be required to act as a downcast airway for the ventilation system associated with the northern underground workings.

Jan 1, 1957

By Misra A

After review of the status of research on optirnisation of retreat longwall faces it is argued that an acceptable optimisation model must be based upon realistic cost data that take into account not only the face costs, but the total panel costs. These include the cost of development, face cost, removal and installation cost. The determined optimum length of a retreat longwall face is based upon a realistic model and actual costs.Parameters that influence the optimum face length have been varied over wide limits to allow determination of the sensitivity of the model and the effect of the parameters on the optimum face length. It is concluded that for medium production rates and medium system availability, the optimum face length of a retreat longwall face under Australian conditions lies between 180 and 220 metres.

Jan 1, 1995

In this paper is given a description of the flotation plant recently erected by Broken Hill South Limited at the South Mine, Broken Hill, N.S.W. It has been built on the site of the old flotation plant, which was described in a previous paper published by the author. The present paper is supplementary to the former paper in that it replaced the following sections thereof, namely, those from end of the second paragraph, page 269, to the end of the first paragraph page 282, and from the end of the second paragraph, page 284, to the end of the third paragraph, page 302.The roll crushing, fine grinding, gravity concentration, filtration, disposal of products and sampling in the new plant are the same as described in the above mentioned paper.The reconstruction of the flotation section, described herein, completes the reconstruction and modernisation of the treatment plant which was begun in 1928. A description of these earlier alterations has already been published in the Proceedings of this Institute.

Jan 1, 1935

By J N. Farrell

Metallurgists frequently use a small number of large samples to characterise expected mill performance, with the a priori assumption that these few samples are representative of the entire deposit. Geometallurgical sampling is becoming more prevalent as a way to use many smaller samples to indicate the expected recovery as part of the Mineral Resource or Ore Reserve estimation.The evaluation of magnetite deposits involves specialised approaches to sample preparation, sample analysis and resource estimation. The sampling protocol for magnetite deposits will typically include the use of Davis Tube analysis. The Davis Tube is a mini-pilot plant that is used for determining the mass magnetic recovery from a small amount of sample ground to a specific size. The magnetic concentrate may then be analysed and together with the mass magnetic recovery, may be used to simulate the expected mill recovery. The magnetite sampling protocol is specific to each deposit, and is typically designed around a specific metallurgical flow sheet.During resource modelling, the mass magnetic recoveries and concentrate grades may be estimated directly or assigned to a block model using regressions with other chemical constituents. For estimation, the concentrate grades are weighted to account for the different mass magnetic recoveries of each sample and the impact of these differences on the concentrate estimates.

Sep 5, 2011

By J Harding, S Munro, R A. Bearman

Despite the importance of the primary crushing stage, performance optimisation is not well analysed with sufficient focus to give improvement opportunities. At the Newcrest owned Telfer operation, liner life plays an important part in scheduling planned maintenance. Major consideration is given to monitoring crusher performance, as the highly abrasive nature of the feed significantly impacts the liner wear life. A study was undertaken by the lead author which focused on establishing a strong baseline of accurate data pertaining to the performance of the crusher, in terms of, operating parameters, liner life and key machine design factors. As part of the study, mining feed materials were examined for a particular set of liners and this revealed that improved methods should be pursued. Due to the competitive nature of the mining industry, the business solution to complex problems with long shutdown cycles should be streamlined to incorporate a non-operational modelling approach that is significantly more efficient than traditional online trial and error methods. In order to dramatically reduce the time and business risks, it was decided to engage services to model and simulate the liner life by varying main operational and mechanical factors. The key to all simulation work is gathering high quality baseline data. Such data allowed deployment of the Kinematic Crusher Model and validation of the model against worn 2D wear liner profiles. The proven model was then successfully deployed to predict operational values that defined crusher performance. To enhance the study, further investigation into a set of mechanical and operational simulations generated a sensitivity matrix measuring key performance parameters throughout the wear life of the liners. The study revealed throughput as a highly sensitive parameter and a change in eccentric throw provided the greatest improvement in extending liner wear life.

Aug 24, 2022

By V Mutton, L Potts, D Joyce

This paper describes the method of extracting sill pillars within the underground operation from under unconsolidated mullock fill at the Cracow Gold Mine. This pillar recovery method was initially successfully used to recover sill pillars at Crusader Mine, Western Australia in 2001. Globally significant resources have been sterilised due to the placement of loose rock fill above crown pillars and within adjacent stopes. The method described here offers significant opportunities to increase recovery of sill pillar recoveries.The royal orebody sill pillars at Cracow Gold Mine form a significant resource. Extraction of these pillars needed to be undertaken with minimal ore dilution and maximum ore recovery. The application that was selected to consolidate the loose mullock fill above each pillar used an injection grouting process (Minova FB200).Cracow Gold Mine mining method is bottom up bench mining. The pillars were left within the orebody to allow for stoping to commence whilst the decline was being developed. Due to the remainder of the orebody being extracted the only access to consolidate the backfill was from the sill pillar extraction level. Numerous problems were encountered and overcome from product selection and trial, system of injection to extraction.This pillar recovery process achieved a 95 per cent recovery of the sill pillar compared with an estimated 60 per cent typical for other mining options.CITATION:Potts, L, Mutton, V and Joyce, D, 2012. Pillar recovery at Cracow gold mine using grouted consolidated mullock, in Proceedings Narrow Vein Mining 2012 , pp 179-184 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

By G W. Swana

Elastoplastic parameter is a parameter that describe how much materials behave elastically up to certain stress states and plastically thereafter (Hudson and Harrison, 1997). In the continuum analysis, two main parameters of the elastoplastic parameter are modulus elasticity and Poisson’s ratio. In the slope, elastoplastic parameter holds the main role for stability related to deformation in ductile type of rock. There’s a limitation to determine elastic or plastic deformation at the field for ductile rock type. Field manifestation commonly showed that there was no accumulation zone during and after the sliding failure mechanism, in other hand, at the research area, manifestation of deformation at the toe of slope only indicated by bulging shape. This paper will focus at the sliding failure occurred at Coal mining Pit Y owned by Arutmin Indonesia, which according to failure investigation report similar with the condition described above. This paper also will be based on two hypotheses, first hypothesis is claystone rock mass has not been reached plastic deformation yet and the second hypothesis is there is a chance that elastoplastic parameter of the rock mass has been changed during the deformation/sliding failure process. Research method of this paper are back analysis using probabilistic analysis in Finite Element Method (FEM), which conducted before and after failure. Then, the result of the displacement or deformation of the analysis will be checked with the actual deformation shape. Meanwhile, the change of the elastoplastic parameter will be analysed and interpreted. This paper hopefully able to be developed to study about elastoplastic behaviour of rock mass in actual condition and the influence of another uncertainty factor which determine the slope stability.

Nov 29, 2022