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By R Riquelme

The El Salvador porphyry Cu deposit (26¦ 15Æ Lat S, ~2700 masl) and associated exotic mineralisation is situated at the back-scarp of the late middle Miocene Atacama pediplain in the western Precordillera. New, together with published 40Ar-39Ar data from El Salvador combined with morphologic analysis reveal that the palaeospring plumbing system related to exotic mineralisation at the Damiana exotic Cu deposit and the local geomorphology has not changed fundamentally between the late Eocene and late Miocene. Stable H/D isotope data on supergene alunite from El Salvador indicate an overall increase in dD values (VSMOW) from -74ë at 35.82 ¦ 0.95 Ma to -23ë at ~11 Ma. The transition from strongly to moderately negative deuterium values occurred between ~16 and ~13.5 Ma. Supergene alunite from the El Hueso (3950 masl) sedimentary rock-hosted epithermal deposit ca 35 km SE from El Salvador was dated at 8.19 ¦ 0.01 Ma and yielded a dD value of -25ë. We interpret the increasing deuterium excess as the result of strong evaporation and recycling of meteoric water after ~15 Ma and as indicative for a change in precipitation patterns and climate desiccation. In contrast, the strongly negative dD value for late Eocene supergene alunite points to a more humid climate and an elevation similar to the present. The late Miocene supergene activity at El Hueso is probably related to an uplift of the Precordillera to elevations sufficient for capture of orographically controlled precipitation. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

A geologic, petrographic and geochemical study has been performed on the pyroclastic flow deposits in the coastal area of East Zhejiang Province, Southeast China. This study leads to classification of the pyroclastic flow deposits into three associations: the extrusive type, the surge type and the ash flow type welded tuff associations. Through detailed investigation and comparison of the characteristics of these lithologic associations, with emphasis on the welded tuffs, a comprehensive model has been proposed to demonstrate the petrogenesis of the pyroclastic flow deposits.

Jan 1, 1995

Investigation on Multicomponent Semi-Autogenous Grinding

Sep 13, 2010

Laboratory scale flotation tests were done on mineral hematite and aspecular hematite ore using oleic acid and sodium oleate as collectors. The mineral hematite floated strongly in the neutral pH region, with an increased pH range of flotation at higher oleate additions. Concentrates with sufficient hematite grade to meet the paint pigment specification were produced using oleic acid and sodium oleate as hematite collectors on the specular hematite ore. Hematite recoveries of 70 per cent at 60 per cent Fe grade were obtained using stagewise roughing. The interaction between hematite and oleate was confirmed as chemisorption but the exact mechanism could not be determined, as two independent phenomena can be used to explain the fact that the pH of maximum grade increased with increasing oleate addition.

Jan 1, 1999

Perception has the unfortunate habit of becoming reality. Urban inhabitants unfortunately do not regard mining as a legitimate or desirable business, despite its contribution to Australia's export income (+A $8,000 million, being nearly a third of all exports); share of GDP (it is 4.5%); and the fact that its presence fills up all the empty spaces northwest of the Adelaide-Melbourne-Sydney-Brisbane crescent of inhabitation. The huge economic contribution of Australia's minerals industry, resulting from providing more than half of merchandise exports (Figure 1), is achieved by employing only some 2% of the national work force (Gaulton, 1997). Unfortunately, the minerals industry's critics generally oppose exploration on the basis that what you don't know will not hurt you. It is the 'do-not-confuse-me-with-facts' philosophy or 'ostrich syndrome', which somehow crudely assumes that mining practices have stayed in the style popular circa late 1800s. Somehow ignorance really is bliss for these idealistic believers, who are reminiscent of the members of the Flat Earth Society!

Jan 1, 1997

Kinetic Study on the Leaching of Vanadium from LD Converter Slag Using Sulfuric Acid In order to reduce the environmental impact due to land disposal of LD (Linz-Donawitz) converter slag from steelmaking plant and to valorise this waste material, an acid leaching study was carried out to assess the effect of several parameters on the kinetics of vanadium dissolution. The characterisation and morphology of the feed investigated using XRD, XRF. The factors influencing leaching vanadium such as particle size, temperature, slurry density and the concentration of sulfuric acid were investigated and optimised. The maximum vanadium recovery about 95 per cent achieved at 70¦C, S/L: 1/15, acid concentration: 3M and for 150 minutes of leaching time. The dissolution of vanadium in sulfuric acid shows that there are two stages in the kinetics of leaching. At the first 15 minutes, there is a sharp increase in the amount of vanadium extracted and at longer leaching time, the extraction increase slightly. In the present work, the shrinking core model (SCM) was used to describe the acid leaching of vanadium compounds. A summary of the controlling regimes in the SCM are examined below for short time (less than 12 min.) and long time (more than 30 min.) stages. So, it was found that the kinetics of leaching in both stages is controlled by solid product diffusion regime.

Sep 13, 2010

Bacterial Leaching of Complex Polymetallic Sulfide Ore The work described here concerned the study on bacterial leaching of complex sulfide minerals and polymetallic ores operated in shaken flasks and small-scale columns. The bioleaching of jamesonite was not accessible. The iron extraction in pyrrhotite leaching reached 98.2 per cent after 23 days. After 26 days, the zinc extraction of marmatite reached 92.3 per cent while the iron extraction only reached 13.6 per cent. The pulp density had effect on the metal extraction of pyrrhppite and marmatite. For complex polymetallic sulfide ores, after 10 days in shaken flasks, 97.1 per cent zinc extraction was achieved. While after 60 days in small-scale column, the zinc extraction only proceeded to 7.8 per cent; By SEM and EDXA of experimental samples and their leaching residuum, the bioleaching mechanism was discussed.

Sep 13, 2010

By A Kemp, I Taylor, S C. Lamoureux

Detailed landform designs were completed for six (integrated) iron ore waste rock dumps at a Western Australian iron ore mine site to meet closure objectives and to optimise material movements for closure. The designs were based on specific physical and geochemical properties of waste material and the design was undertaken to enhance long-term stability of the dumps and optimise material movements, and therefore minimise closure cost. Construction of the re-shaped waste rock dumps have been completed. Following construction, surface material characteristics were found to deviate from those used in the design assessment. Materials present at surface following re-shaping were generally finer textured than those sampled for modelling. It is anticipated that the embankment slopes may experience increased rates of surface erosion compared to the rates predicted from modelling and used in design. The finer textured material is thought to be generated from exposing finer material that has migrated into the coarser matrix over time or that was not present in the sampled top surface of the landforms. This is due to armouring processes over time and this phenomenon is likely to recur following further wet seasons. The majority of the waste materials present in the waste rock dumps were subgrade banded iron formations (BIF) and chert, which are generally competent and geochemically inert. Some waste material was known to have an elevated risk of erosion but present in relatively small quantities. The presence of a large number of dolerite dyke swarms indicates appreciable volumes of dolerite were produced as waste from the pits. This material has an elevated risk of being highly erodible/dispersive. Clays and shales are also likely to be present in the dumps and are considered to be less competent material (relative to the BIF/chert). This paper presents the process from upfront materials assessment through detailed design to construction of the rehabilitated waste rock dumps, and post-construction sampling and testing to validate model findings.CITATION:Kemp, A, Taylor, I and Lamoureux, S C, 2017. Design to closure – construction of detailed rehabilitation designed iron ore waste rock dumps based on upfront site specific assessment, in Proceedings Iron Ore 2017, pp 353–358 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By J Fisher, M Castro, A Hariyadi

The train haulage system being designed for PT Freeport Indonesia’s Grasberg Block Cave (GBC) will be located within the mine at an elevation of almost 3000 m above sea level on the west side of the island of Papua, Indonesia. The developing block cave is beneath the active Grasberg Open Pit and will transport 160 000 t of ore per day from multiple chute galleries to the underground crushing plants. The design entails 28 km of rail and 119 ore chutes, which will be brought online over the course of ten years.The train haulage system will be driverless and fully automated. Sequentially, the system includes remote controlled rock breakers at the top of the chute grizzlies, followed by remote controlled chute loading of the trains, then autonomous train haulage and autonomous unloading. An overhead catenary system (OCS) will power the locomotives, which are equipped with on-board batteries to drive through the loading and unloading sections. Service locomotives with drivers move material-laden freight cars in and out of the service shaft, destined for workshops, the magazine and batch plants. Service locomotives are also used for haulage level maintenance. Highly reliable and redundant control and communications systems are required to manage 12 trains in simultaneous operation.This paper provides an overview of the train haulage system’s technical complexities and the associated support systems interactions. The paper also highlights the project management issues and successes of this globally sourced project.CITATION:Hariyadi, A, Castro, M and Fisher, J, 2016. Automated train ore transport, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 563–570 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By L Barro

There is currently a worldwide interest in coal-oil technology as the search continues for alternative energy sources to reduce the consumption of petroleum crude. An important aspect of this coal-oil technology study is to obtain information on the flow properties of coal-oil slurries. While some work has been reported on the flow behaviour of black coal-oil suspensions, very little work on brown coal-oil suspensions has been reported. In this paper flow characteristics of brown coal-oil suspensions for various coal concentration and temperatures have been presented. A capillary rheometer, designed to handle settling suspension, has been used for determining rheological properties. Brown coal of 0.0725 mm average particle diameter has been used in this work. The oil was a coal derived product having a boiling point range of 234¦C - 319¦C. Apparent viscosity of all suspensions was found to increase on storage due to ageing. Ageing might have occurred due to physicochemical interactions between coal and oil. Flow behaviour of some suspensions changed from Newtonian to non-Newtonian on storage. Apparent viscosity increased sharply with increase in solids concentration and suspensions at higher concentration behaved as non Newtonian liquids. Viscosity decreased with increase in temperature; rate of decrease slowed down with increase in temperature.

Jan 1, 1980

This paper presents an analysis of the production data for the period 1861 - 1953 from hydrothermal gold-silver deposits of the Hauraki Goldfield. To directly compare the metal content of the deposits a figure of ounces of gold equivalents (oz gold equivalent) is calculated from the value of the gold-silver bullion produced from each deposit. Frequency distributions for ore tonnage and oz gold equiv. appear to be lognormal and show a high proportion of very small deposits, with 90 per cent less than 100 000 tonnes. The deposits when plotted in order of size fall roughly on a smooth curve which suggests that the size distribution is not random. A large proportion (68 per cent) of the total gold-silver extracted from the Hauraki district was contained in the largest deposit û Waihi. A technique used for predicting undiscovered mineral resources is ZipfÆs law, which relates the size of an item to its rank order. The figures for ounce gold equivalents from the major Hauraki deposits fit ZipfÆs law remarkably well. Taking Waihi at 6.8 million oz gold equivalent as the rank one deposit, Thames is number five and Karangahake number seven. A Zipf plot indicates that down to rank 100 (68 000 oz gold equivalent) only 28 per cent of the total gold-silver resource in the Hauraki Goldfield has been extracted. A further 72 per cent or 25.4 million oz gold equivalent, including the deposits of rank 2, 3, 4, 6, 8, 9 and 10, are undiscovered. However, since some deposits will be deeply buried under younger rocks and others will be under the sea only a proportion of the total resource will be discoverable.

Jan 1, 1981

By D J. Black

The process of longwall coal extraction coal causes fractures in the overlying and underlying strata and these fractures become pathways for gas released from adjacent coal seams to flow into the mine workings and contaminate the ventilation air. If the rate of gas emission exceeds the diluting capacity of the ventilation air, the gas concentration will increase and exceed the statutory limit resulting in production delays.All potential gas sources within the planned mining area, including coal seams located above and below the working seam, should be identified and sufficient gas data collected and used to determine the specific gas emission from each gas source. Gas reservoir and emission modelling is recommended to determine specific gas emission and changes in gas emission from individual sources over the planned mining area. Accurate gas reservoir and emission modelling provides the information required to accurately design gas drainage programs to effectively manage gas emissions and minimise the risk of ‘gas-outs’.Given the increasing occurrence of incidents of gas concentration in ventilation air exceeding the 2.0 per cent statutory limit and changes to mine plans to avoid ‘difficult-to-drain’ areas, it is apparent that many operations are not effectively utilising gas reservoir and emission modelling to identify high gas emission areas and are not completing sufficient gas drainage in advance of planned mining.The process of gas reservoir and emission modelling to support gas drainage design to control tailgate gas concentration and fugitive emissions is presented and discussed.CITATION:Black, D J, 2017. Gas reservoir and emission modelling to evaluate gas drainage to control tailgate gas concentration and fugitive emissions, in Proceedings Australian Mine Vent Conference 2017, pp 65–72 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By P Phelan

This paper presents the general background and development of raiseboring followed by case histories of circumstances where raiseboring equipment was used in a different manner to normal. Each project has been summarised for this paper as described below: Case 1: Retrieval of a 40 tonne truck from a stope at Peak Gold Mines. Case 2: Slot raising - Conventional, Uphole and Downhole Reaming at Peak Gold Mines. Case 3: Reamer recovery by Downreaming at Tower Colliery. Case 4: The importance of Mucking Raisebore Holes û Thalanga Project. Case 5: Pilot Drilling Dewatering Holes at Beaconsfield Gold Mines. Case 6: Low angle æcut offsÆ in vein at Telfer Gold Mine.

Jan 1, 1998

By K F. Tang, J-W Li

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Xiong’ershan district in the southern margin of the North China Craton (NCC) contains more than 20 gold deposits hosted in the late Neoarchean to early Palaeoproterozoic amphibolite facies metamorphic rocks or late Palaeoproterozoic unmetamorphosed volcanic rocks. Gold mineralisation consists mainly of auriferous quartz veins and disseminated ores in hydrothermally altered zones, with additional gold mineralised breccia pipes. Gold orebodies are strictly controlled by secondary- or higher-order brittle/ductile-brittle faults. Isotopic dating reveals two separate episodes of gold mineralisation: the Shanggong and Dianfang deposits formed in the range of 236 ± 1.4 to 202 ± 18 Ma, whereas the Gongyu, Qianhe and Qiyugou deposits formed between 135.0 ± 0.5 Ma and 124.0 ± 1.0 Ma. Stable isotope and noble gas geochemistry studies indicate that the Triassic gold deposits were precipitated from deeply-sourced, low-salinity fluids at 250–350°C, but whether the fluids were mainly derived from metamorphic devolatilisation or magmatic degassing remains unresolved. In contrast, the Early Cretaceous deposits most likely precipitated from a dominantly magmatic fluid, although metamorphic and meteoric components cannot be ruled out. Results from this study, when combined with regional geological and geochemical data, suggest that the Triassic gold mineralisation was generated by the deformation associated with the collision between the North China and Yangtze cratons, forming the Qinling-Dabie orogen. In contrast, the Early Cretaceous gold veining was a result of lithospheric destruction of the NCC, a process initiated by plate subduction from both the south and north since late Palaeozoic but ultimately triggered by the westward subduction of the palaeo-Pacific plate in the late Mesozoic. This study helps to reconcile the long-term debate on the timing, genesis and geodynamic setting of gold mineralisation in the Xiong’ershan and other districts along the southern margin of the NCC.CITATION:Li, J-W and Tang, K F, 2015. Gold deposits in the Xiong’ershan District, Southern North China Craton – products of Triassic deformation and Cretaceous craton destruction, in Proceedings PACRIM 2015 Congress, pp 341–344 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

Phosphorus Phase Analysis of Medium-Low-Grade Rare-Earths-Bearing Phosphate Ores

Sep 13, 2010

By K Firmin

The Mt Tom Price orebody of Hamersley Iron Pty Limited consists of a folded hematite - shale sequence capped by a layer of goethite. Consequently, variations in iron content occur within the ore body, and as the overall grade is below that required to make specification products, selective mining must be carried out. A necessary preliminary to quality control of products based on selective mining is the production of advance data on the tonnages and grades of material to be expected in future mining areas. Bench plans showing zones of different grades and types of material anticipated are prepared from structural geological information. The grades of materials on a bench are essentially governed by the positions and attitudes of the shale bands. Quality control is exercised by blending different grades and types of material in primary crusher feed. Iron grade is the prime grade consideration although sometimes the level of phosphorus content must be considered. Pre-production grades are determined from assay of samples taken from blast hole cuttings. As shales are more friable than hematite, product fines are always lower in iron grade than the lump product. The realisation of contract specification grade is more difficult with fines than with lump, so maintaining the correct fines grade becomes a prime factor in quality control. Control of fines grade is presently effected by aiming for an appropriate feed grade to the primary stockpile. Studies to estimate fines grade directly by qualitatively taking into account material types are in progress. Quality control measures are checked by monitoring the crushing and screening plant output, and taking appropriate compensatory actions in the mine when required. Minor fluctuations in quality of fines can be blended out on stockpiles. The quality control measures described ensure constant quality products, and a good recovery of high grade material from the deposit.

Jan 1, 1971

By R C. A Minnitt

This paper illustrates the use of variography and moving average plots as an aid to analysing variations in the process that can be used to direct the improvement efforts. The hydrometallurgical processes used in manganese metal production consist of sequential unit operations that include milling and reduction of manganese ores. Leaching of the reduced ore, is followed by solid-liquid separation, residue disposal, solution purification and electrowinning of manganese metal completes the process. The nearly 250 integrated process control loops rely on reports of pH, flow pressure, level, temperature and chemical analyses. Metallurgical accounting, reconciliation and process control is achieved through monitoring of the chemical and mass balances within the manganese reduction plant, requiring approximately 50 000 analyses of solids, powders and liquids each month. The largest numbers of samples are taken in the cell house. Changes and variations monitored by sample statistics ensure that the manganese products comply with predetermined specification limits. Optimising the information-value of the approximately 50 000 samples in the manganese plant is carried out in tandem with ongoing process optimisation. Variographic analysis of daily sampling data suggests that the cyclical behaviour evident in the moving average plots is only a reflection of random residual variability and not a reflection of true underlying variability related to cyclical phenomena. Low resolution in the variogram of daily sampling data masks the short-range variability that emerges when hourly data are analysed. Hourly samples collected over a 39-day period (giving 941 sample data), helped identify short-range cycles in the process. The relative distribution of variability for daily sample intervals, indicate that 57 per cent arises from V[0], 18 per cent from V[process] and 16 per cent from random residual variation. V[0] includes all the uncontrolled sampling error arising from a poor sampling protocol, the fundamental error (FE), the grouping and segregation errors (GSE), the delimitation error (DE), the extraction error (EE), etc. This confirms the suspicions regarding the suboptimality of the sampling protocol and the way it is implemented. The absence of long-term trends in the leach suggests that short-term variation (less than one day) dominates the process. While the control charts indicate that the overall processes are maintained above the lower specification limits and the target values, there is nevertheless a considerable amount of variability in the system that overhangs the processes and threatens to impact them negatively. Although the variability in the leach is above the prescribed limits, the volatility is a matter of concern because it seems to be uncontrolled. The comparison of the various sources of variability in data collected on an hourly basis suggests that the short-term random variability (V[0]) accounts for almost 50 per cent of the variability in the process. The main source of this variability is due to errors in the sampling protocol and is probably related to the size of the fundamental error (FE), the grouping and segregation errors (GSE), the delimitation error (DE), the extraction error (EE), etc. Remediation of FE and GSE will probably lead to a reduction in V[0], whereas V[process] could be mitigated by reducing the biases associated with DE and EE in particular.

Jan 1, 2008

By S M. Aminossadati, R Bagherpour, F Hasheminasab

Mine ventilation is an essential part of underground mining operations used to provide fresh and cool air, as well as to dilute and remove contaminants from the work environment. This paper presents an overview of the ventilation and gas management systems in one of the underground coalmines in Iran: Parvadeh_1 mine. The mine is located in the Tabas coalfield in the South Khorasan province. It is the only fully mechanised mine in Iran utilising the longwall retreat technique. The mine produces 1.1 to 1.3 Mt of coking coal annually. The mine ventilation system currently utilises two 630 kW exhaust surface fans. The gas management system includes surface to in seam (SIS) predrainage boreholes. The underground mine is equipped with an underground gas reticulation pipeline that is connected to a surface plant for the production of methane gas. This study shows that the ventilation and gas management systems of the Parvadeh_1 mine are in line with the standards of Australian underground mines.CITATION:Hasheminasab, F, Aminossadati, S M and Bagherpour, R, 2017. An overview of ventilation and gas management systems in an underground coalmine in Iran, in Proceedings Australian Mine Vent Conference 2017, pp 41–46 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By T Graham

Traditional iron ore wet beneficiation plants are large multilevel structures, often integrated into centralised processing plants. They are characterised by sizeable footprints, substantial water and power consumption, inflexible design and low scalability. Significant design changes that address these issues need to be made before relocatable modular plants become feasible. Firstly, large amounts of processing water are required in standard wet plants, so it is vital that water consumption is reduced to an absolute minimum. Secondly, the process of depositing tailings into tailings storage facilities (TSFs) is environmentally destructive, consumes significant power and requires lengthy approvals to be completed. Thirdly, modules need to be easily and quickly relocatable.The solution to reducing water usage and eliminating TSF requirements is accomplished by providing a tailings dewatering and dry-stacking capability into a separate module. This equipment needs to dewater tailings to a point (typically below 20 per cent moisture) where dry stacking becomes possible – design is mainly driven by material rheology and particle size distribution (PSD). In this respect, a flexible and scalable strategy is employed to dewatering modules, allowing a variety of components such as dewatering cyclone clusters, paste thickeners, fine mesh vibrating screens and filter presses to be used to achieve the necessary moisture level, enabling the final dry stacking to be accomplished by a simple telescopic stacking system. Plant relocatability also requires modules to comply with mass and dimensional constraints, as well as ‘plug and play’ ease-of-use features.For coarse particle upgrade, jigs provide a low-cost and effective solution, whereas fine and ultra-fine Fe units can be recovered using Wet High Intensity Magnetic Separation (WHIMS). Recently, sensor sorting – a dry process using X-ray fluorescence, X-ray transmission, laser or other sensors – has begun to make an impact in coarse particle separation, although capacities are still low. The overall objective of a plant is to provide an Fe upgrade of four to five per cent with a feed of up to 4 Mt/a and a recovery of approximately 50 per cent.CITATION:Graham, T, 2017. Relocatable modular beneficiation creates value from waste, in Proceedings Iron Ore 2017, pp 167–172 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Efficacy of Enhanced Gravity Separator in Processing Indian Iron Ore Slime The slime sample was subjected to concentration using Falcon concentrator for their enrichment. The effects of three important variables, eg bowl rotation frequency, back water flow rate and per cent solid were studied on the process performance. Increasing the rotation of the Falcon bowl, enable more material to the underflow by increasing the yield, whereas, the iron content decreases steadily with increasing the rotation of the bowl. The increase in the back water flow effectively removes the clay materials from the underflow at the expense of the yield. Similarly, increasing the per cent solid concentration in the feed produces a better product both in terms of yield and Fe content. Results show that EGS/Falcon can be used for processing Indian iron ore slime and producing pellet grade concentrate.

Sep 13, 2010