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By Thomas CG, Armstrong GJ, Lynch KS

A small glass walled pot grate has been used to simulate drying of iron ore pellets in a travelling grate plant. This equipment has enabled the effect of decreasing grind and de- creasing pellet bulk density on plant production to be quantitatively predicted. These predic- tions are compared with plant experience. The use of the laboratory simulator in comparing the effect of various additives on plant production is also described and substantial improvements in both the goethite and free-water drying periods are predicted.

Jan 1, 1972

By Garland W

Access to geoscience reference informa- tion including mining and mineral processing has increased considerably in the last five years in Australia. This has been due principally to the use of computer-based information storage and retrieval systems. The main reference data base for the mineral and petroleum industries and disciplines in Australia is the Australian Earth Sciences Information System (AESIS), cooperatively developed and coordinated by the Australian Mineral Foundation (AMF). AESIS is created on the CSIRO computing network (CSIRONET) which has a CYBER 76 host computer located at the CSIRO Division of Computing Research (DCR) at Canberra. Data entry was until recently carried out by AMF using a dedicated line through the Adelaide CSIRONET node to the CYBER 76 interactive system. Data entry is now done directly at the AMF on a DEC PDP 11/44 mini computer that is also a host work station on CSIRONET. Data collection via magnetic tape media input from other computer-based systems is under development. The software used for data entry and management of the data base was developed by CSIRO CILES Systems Development Group. For public interactive online use the AESIS data base is transferred by tape to AUSINET - the Australian information net- work run by ACI Computer Services, Melbourne, where the data base is converted to a form suitable for the IBM STAIRS software. CSIRO facilities at DCR Canberra are used to produce computer type-set camera ready products and output in microform, on magnetic tape or as graphic display. Keywords: Earth sciences information, Computer applications, Information storage and retrieval, AESIS, Data bases, Australia.

Jan 1, 1983

By Ghose AK

Design and selection of support systems for longwall faces call for in-depth know- ledge of strata mechanics and in particular of strata-support interactions. The paper presents the results of field investigations and analysis of a difficult-to-cave roof using powered supports under a massive dolerite sill in Central India using a state- of-the-art datalogger system. The mechanised long wall face was equipped with 4/680 tons chockshields operated on the IFS mode using a 300 KW DERD shearer. The datalogger system was capable of storing data simulta- neously in 32 channels. The paper describes the monitoring system and the monitoring programme. The system provided useful information on support behaviour, build- up of leg pressures and face convergence during an intense dynamic periodic weighting phenomenon which destroyed the integrity of almost half of the face supports. At this point, the face had advanced by about 197 metres from the barrier. The paper outlines a post-mortem analysis of this dynamic event and provides a critical evaluation of the data collected for understanding strata support interaction and the behaviour of the massive sill in the overburden.

Jan 1, 1992

The elements of consistent structural de sign models for underground structures are explained. Such models should comprise at least ground properties, excavation and support methods, computational models for analysis, failure hypotheses, and in-situ monitoring. The fundamental characteristics of the interaction between ground and support are investigated. Then, plane strain models for soft ground tun- nelling and design models for rock tunnelling employing stress release at the tunnel face are elaborated. Some numerical evaluations are gi- ven in diagrams, comparing approaches of dif- ferent authors. Comments are presented on nume- rical three-dimensional models (visualized by structural models for mining in rock salt), on the interaction of in-situ monitoring and design, on structural safety for underground structures, and finally on the general develop- ment of structural design models in geo- Techniques.

Jan 1, 1987

The paper considers the nature of outbursts of coal and firedamp as they occur. t follows the development of methods of working used to try and induce outbursts safely under controlled conditions and details the life support systems used to provide maximum rotection to persons who may be affected by s_lontaneous outbursts. Tilt: NATURE OF OUTBURSTS IN THE UNITED KINGDOM .1y some areas in the coalfields of the ingdom are affected by outbursts of :hal and firedamp. The main area affected is he western end of the Anthracite coalfield r: West Wales. In this area 206 outbursts .eve been recorded resulting in the loss of 8 lives. Anthracite is a high rank coal produced v the geological effects of age, depth and ynamic metamorphism. Outbursts have been xperienced over a wide area of the anthracite field but have been most frequent, and most evere, in the areas where carbon content is its highest and where the coal measures cave been subjected to the highest degree of eulting and overthrusting. Most outbursts ire associated with geological abnormalities ,:id the coal ejected during outbursts is sually of a soft and powdery nature.

Jan 1, 1980

By C Grobler, M Recklies, G Jiang, I Taylor, M Morgan, G MacDonald, L Smith

The resource estimation of lateritic deposits, such as Aurukun, presents specific issues related to the lateral changes in thickness and elevation of the various horizontal layers (or zones) within the deposit where the x and y dimensions are orders of magnitude greater than the z dimension. The objective was to develop a three-dimensional (3D) block model that retained the vertical and lateral variation inherent in deposits of this type to allow full optimisation of the production plan without prior selection of an economic portion (enriched bauxite layers) of the profile at the resource estimation stage. The Aurukun bauxite deposit is held by Chalco Australia Pty Ltd (Chalco) and forms part of the world-class Weipa bauxite province, Cape York Peninsula, Queensland, Australia. The bauxite is predominantly pisolitic with an upper boehmite-rich zone and lower gibbsite-rich zone. The bauxite consists of both in situ and reworked domains, is overlain by a thin soil horizon and has kaolinite clay as a transitional base. A portable infrared mineral analyser (PIMA) was utilised on site, in addition to elemental assay, on each drill sample to determine the mineralogy, in particular levels of boehmite, gibbsite, kaolinite and reactive silica. As part of the scope of work, a field program was undertaken using large diameter Boart Longyear sonic drilling to acquire detailed density measurements across the deposit to allow compliance with Joint Ore Reserves Committee (JORC) reporting requirements. Interpretation of the stratigraphy was conducted on a hole by hole basis with definition of the zone layering based on stratigraphy, geochemistry and mineralogy. The zone boundaries were then modelled as 3D surfaces and used to constrain a block model. The block model estimation used the ordinary kriging method, with the estimation done in unfolded space and then refolded, therefore maintaining the zones irrespective of thickness or orientation. The unfolding process converts the real-world positions for both blocks and informing samples to a scaled position relative to the roof and floor of each zone. Analysis of the data and variography were also undertaken in unfolded space. The x and y dimensions are unchanged, but the z dimension is a relative position. The effect of the unfolding and limits on number of samples per hole is to æpushÆ the informing sample search sideways but within the stratification, rather than vertically. This honours the strong vertical zonation within the bauxite profile. The JORC Code requires that the stated resource must have æreasonable prospects for economic extractionÆ. This is a qualitative rather than quantitative definition. A number of selection criteria to define a resource roof and floor were developed in consultation with the project engineers and owners to meet these criteria. The vertical selection of material to include in the resource highlights the variation in the development (and destruction) of the bauxite profile from area to area within the deposit.

Jan 1, 2009

By Myers I. A, Peters S. G, Bultitude R. J, Dowling K

Gold-quartz and antimony-gold-quartz veins in the Hodgkinson Province are hosted by subgreenschist to greenschist facies metasediments and show no spatial association with granitic rocks. They commonly parallel axial plane foliations or occur in brittle to brittle-ductile shear zones. Detailed mapping in the Hodgkinson goldfield indicates that vein systems are isolated in distinct structural and lithologic domains by post-mineralization faulting. Gold-quartz and antimony-gold-quartz veins have distinctive mesoscopic textures characteristic of the mesothermal vein environment. Some of the antimony-gold-quartz veins are located on domain boundaries which truncate the gold mineralization. In. some areas, tin and tungsten-tin mineralization which are spatially related to Late Palaeozoic granitoids appear to postdate the gold-quartz and antimony-gold-quartz mineralization.Oxygen and hydrogen isotopic studies of vein and alteration assemblages associated with these diverse ores provide constraints on fluid sources and have implications for the origin of mesothermal gold mineralization. The available isotopic data are consistent with a dominantly magmatic source for tin and tungsten-tin mineralization although there is evidence of a late-stage meteoric component in some tin-mineralizing systems. Although a distal magmatic contribution cannot be entirely discounted, the gold-quartz and antimony-gold-quartz veins were probably deposited from deeply

Jan 1, 1990

By Jowett A

To compare open circuit lead primary rougher results at Mount Isa Mines Ltd., eleven surveys were made over five weeks of plant operation with varying ore sources, including a specially hauled sample of 100% Black Star ore. Three of the surveys which represented extremes in performance were selected for sizing, cyclosizing and assaying for lead, zinc and iron. A comparison of the flotation kinetics has revealed the similarities (including common problems) and differences for the surveyed ores. The concepts of entrainment and collectorless flotability are used to aid interpretation of the kinetic data.

Jan 1, 1978

By R Barritt

Remedial options for a waste rock dump (WRD) were considered as part of closure planning studies at an active mine in Western Australia. To minimise the impact of any seepage from the landform it was determined that placement cover system utilising the moisture ‘store-and-release’ concept was appropriate. The purpose of the cover system was to:•Reduce net infiltration of meteoric water to attenuate peak concentrations for contaminants of concern in natural receptors to levels that can be assimilated without adverse impact to the surrounding ecosystem; •Provide a growth medium for establishment of a sustainable vegetation canopy; and •Improve current quality of surface water runoff from waste storage areas.The project comprised several phases of work: materials characterisation, numerical soil-plant-atmosphere (SPA) modelling and finally cover system construction and monitoring equipment installation.CITATION:Barritt, R, 2018. Conclusions from long-term cover system performance monitoring – a case study, in Proceedings Life-of-Mine 2018, pp 101–105 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By Cocker A

Pre-splitting for smooth highwall formation is conducted in around 75 per cent of surface coal operations within Australia. The CMTE (Centre for Mining Technology and Equipment) in conjunction with BHPAC (BHP Australia Coal) initiated a project to look at pre-splitting and to investigate the notching of blastholes for fracture plane control. The notching was specifically for pre-split initiation and also for discing of the toe of the production holes to minimise coal loss from the top of the coal seam. There are currently a number of factors which are driving the introduction of new pre-splitting technologies and products. The first is the ever increasing bench height being employed in strip mines which require a higher quality wall with less blast damage to maintain stability. Currently depths of 55 metres are common place with depths of 70 - 80 metres fast approaching. The second factor is the introduction of new technologies or methods which require a high quality highwall produced, eg highwall mining. This paper discusses the current state-of-the-art in pre-splitting and the main issues facing successful pre-splitting in the future. The use of a blasthole notching technology to promote fracturing along the pre-split line is also analysed. The review indicates that most pre-splitting challenges in the future can be addressed through better use and developments of current drill and blast technology. It is also concluded that a blasthole notching technique may find niche applications in improving final walls within a surface coal mine, especially where a high quality wall is required. The notched blasthole method may also allow pre-splitting in ground conditions and adverse rock structure which currently cannot be pre-split by existing technology.

Jan 1, 1995

By J Player, P Mikula, G Sweby

A numerical modelling back-analysis exercise was carried out at a WA gold mine at which early signs of seismicity (rock noise, scatts from active faces) were becoming apparent as depth of mining increased towards the 500 m mark. Some strain bursting had occurred and it was necessary to discover what the implications of this were for greater depth. The aim of the modelling was to: 1. Establish a correlation between observed ground conditions and model predicted damage, in overstressed areas of the mine. 2. Use this correlation to forecast rock mass damage and ground control requirements for proposed future stoping panels at greater depth. Good correlation has been achieved between observed rock mass damage, and a 3D Finite-Element RS3 model, run in elastic mode. Two candidate stress field orientations were modelled. The model parameter best fitting the observations was the Strength Factor (SF), the ratio of strength/stress. The good match (correlation coefficient of 0.7) between observed and modelled suggests that the elastic approach is justified for the depth range and rock mass properties analysed. The correlation also enabled a link between observed damage and installed ground support performance. Using the linear best-fit between observed and modelled, a forecasting exercise was carried out using the same RS3 model, modified to include future stoping. The resulting damage and ground support categories were obtained from the modelled SF for each proposed stoping level. Also, a series of generic geometries was assessed to investigate the impact of varying stope face lead/lag distance, sill pillar height and stope pillar size, on ground conditions. The key finding of the generic geometries were: • Ground support schemes have been defined for the expected conditions. • All ore drives are expected to have significant damage in the backs and rehabilitation. • Lead/lag distance not to exceed 10 m. • Sill pillar/level intervals of less than 20 m require an increase in ground support scheme. • Pillar sizes for maintaining footwall and hanging wall stability should be at least 10 m × 5 m.

Nov 29, 2022

By M Rafty, A Markham, S Atkinson

Australia contains some of the most productive mining areas and is characterised by ancient landscapes and highly variable hydrology. Historical mining of iron ore, coal and other minerals has targeted ore deposits located above water tables, and elevated above creek lines where possible to reduce cost. The downturn in mining caused by falling ore prices over recent years has triggered a drive to reduce cost, maximise yield and delay capital expenditure associated with opening new mines. So as the ore deposits with more favorable mining conditions become depleted there is an increased focus on mining ore associated with valley floors and creek lines. This is demonstrated by a regional assessment of the extent of Channel Iron Deposits (CID) and Iron Ore (Fe) Mines and Deposits in the Pilbara Region of Western Australia (Figure 1). A large proportion of these mines are, or plan to, target high grade CID ore associated with existing creek systems. Figure 2 shows outcropping and inferred sub-cropping CID extents, which suggests there are vast quantities of CID ore deposits throughout the Pilbara Region, intersected by major creeks which could be mined at some point in the future using creek diversions (Atkinson et al., 2017). A similar picture could also be produced for coal mining in Queensland, particularly in areas such as the Bowen Basin.While creek diversions provide an opportunity to maximise the utilisation of these orebodies and extend the life of mine, creek diversions can involve substantial financial, social, environmental and regulatory risks that need to be carefully managed (Markham et al., 2017, Atkinson et al., 2017). This paper discusses the key issues and opportunities associated with diversion decision making. It highlights the importance of using a well-structured assessment methodology that allows key stakeholders to be part of the assessment process and is complementary to material presented in Atkinson et al., (2017). Design considerations for operational and closure designs are presented, as well as mine planning considerations, risks, cost saving opportunities and the benefits of an integrated approach to design. The role technology plays in diversion design and performance monitoring is discussed as are the potential opportunities for the future.CITATION:Atkinson, S, Markham, A and Rafty, M, 2018. Diversion decision making with an integrated approach to design for operations and mine closure, in Proceedings Life-of-Mine 2018, pp 74–79 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By Liu Q, Siefken T. C, Misra V. N

Investigation of the differential flotation characteristics between arsenopyrite and pyrite in a ore concentrate have been carried out on a laboratory Leeds flotation cell. Experimental results indicate that some limited separation between arsenopyrite and pyrite is possible by differential flotation under the conditions of high pH and low pulp redox potential. The best performance in this testwork was achieved by using an oxidizing agent at pH 10.7. Of the oxidizing agents tested, NaOCI gave better oxidizing effect than KMnO4. It has also been observed that the pulp redox potential depends on the pulp pH value. At high pH values a hydroxide layer is formed on the arsenopyrite surface, which has the effect of a depressant on the arsenopyrite.

Jan 1, 1992

By G Balog, T Ormerod, D Cox

This paper discusses the methods utilised by the technical team to identify and quantify the SLC risk factors, the modifications to mine design and scheduling, and the changes to the planned risk management practices. The paper also describes the future work currently planned by the OZ Minerals technical team to quantify the various risk factors in terms of space, time and magnitude. This may better inform the future mining practices within not only the Carrapateena province but also the wider Gawler Craton.

Mar 15, 2021

By G R. Hancock, M J. Saynor, J B. C Lowry, K G. Evans, M Narayan

Tools such as landform evolution models (LEMs) provide a means of predicting how a landform may evolve over extended periods of time. Here, we utilise the CAESAR-Lisflood LEM to assess a proposed rehabilitated landform of the Ranger Uranium Mine in the Northern Territory of Australia (Figure 1). The environmental requirements for the closure of the mine state that the final landform must be able to physically isolate tailings material from the environment for a period of at least 10,000 years (Australian Government, 1999). However, uncertainty exists as to the reliability of model predictions representing thousands of years.In this study, we use model predictions from an undisturbed pre-mine landform to calibrate the parameters used in model simulations of a post-mining rehabilitated landform over a simulated period of 1,000 years. Specifically, we vary environmental conditions such as rainfall, presence/absence of vegetation and surface particle size characteristics in a series of model simulations to determine their impact on the respective landforms, to revise model input parameters as required. A simulated period of 1,000 years was used as it represents a period in which long term landform evolution patterns and trends may be established and identified. CITATION:Lowry, J B C, Narayan, M, Evans, K G, Saynor, M J and Hancock, G R, 2018. Using an undisturbed landform to calibrate long-term predictions of the evolution of a rehabilitated landform, in Proceedings Life-of-Mine 2018, pp 133–137 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By C Balci, D Tumac, A Sheterpour-Mamaghani, E Dogan, A Kocbay, T Erdogan, A Gumus, H Copur, E Altintas

Excavation of vertical and/or inclined shafts in the underground structures requiring careful design and planning. Raise Boring Machines (RBMs) are commonly used for excavation of shafts for different purposes such as ventilation, orepass, and human-material transportation. Proper selection and accurate performance prediction of RBMs are two main parameters affecting the cost estimation and planning/scheduling. Indentation test is one of the most preferred methods that can be used to predict advance rate of RBMs. This study aims at suggestion of new prediction model for instantaneous penetration rate of RBMs based on indentation tests. Different rock (core) samples (with different geological origins) are obtained from the raise boring application projects in Turkey; then, the indentation tests are carried out on them by using a real-life insert (button), which is used in reamerhead cutters investigated in this study. Finally, the statistical relationships between the field performance and the indentation indices are investigated. The study indicates that the brittleness index (the ratio of maximum applied force to corresponding penetration) can be used to predict instantaneous penetration rate of RBMs used in the vertical raise bored shafts excavating rocks having uniaxial compressive strength lower than 100 MPa.

Nov 29, 2022

By J Butler, N Patel, S Narendranathan, S Rastogi

The Yallourn Mine (YM) commenced mining of brown coal in the 1920s under operation by the State Electricity Commission of Victoria (SECV), prior to it becoming privatised in 1996. The present owners of the YM, Energy Australia Yallourn (EAY), acquired the site in 2000 and intend to continue operations until scheduled closure in 2028. Brown coal extracted from the YM is fed into the Yallourn Power Station which supplies approximately 22 per cent of Victoria’s electricity. Water within the YM is collected and stored in the Township Field Fire Service Pond. Water levels within the Fire Service Pond (FSP) may fluctuate considerably depending on the requirement for storage at the site. With due consideration to the stability performance of mine batters adjoining the FSP, the authors performed slope stability assessments to evaluate the risk and consequence of batter instability during the potential pond filling as it approaches the ‘critical pool’. The critical pond is defined as the level at which the driving forces (destabilising forces) are at their greatest and the resisting forces (lake forces, friction) are at their lowest. This assessment was undertaken using the Mine Geotechnical Risk Index (MGRI) approach.

Aug 2, 2023

By Hoberg H, Schneider FU

Flotation tests were conducted with galena, quartz and with synthetic mixtures of the two, in different ranges of grain size, and with different process parameter variants. Physico-chemical analyses were also carried out on surface energy and on xanthate adsorption on galena with different grain sizes. Reference will also be made to hydrodynamics, interfacial chemistry and the influence exerted by grain size in flotation.

Jan 1, 1993

By J Bower

The JORC Code does not specify a definition for ælevel of confidenceÆ. The common approach in the mining industry is to use a certain drill spacing or number of data samples to classify resources by the confidence categories. Another approach includes application of the quantitative geostatistical criteria for non-subjective and consistent definition of the resource categories. This approach, which has become increasingly popular in the mining industry, provides a quantitative measure of the resource estimation uncertainty. In this study, uncertainties associated with the different drilling grids at the Weipa bauxite deposit (Queensland, Australia) have been modelled using conditional simulation methodology. Criteria used at Weipa for defining resource categories are as follows: mineralisation can be classified as a Measured Resource if tonnage and grade of its volume representing three months of production can be estimated with a precision error not exceeding ¦10 per cent (at 95 per cent probability, ie two standard deviations); and mineralisation can be classified as an Indicated Resource if grade and tonnage of its volume representing annual production can be estimated with a precision error not exceeding ¦10 per cent (at 95 per cent probability). Several different grids have been created by subsampling the drill hole database. The studied variables include Al2O3, SiO2, thickness of the bauxite seam and location of the footwall contact. The variables have been modelled by sequential Gaussian simulation. Based on this study the following drill spacings have been recommended: Measured Resources û 150 m by 150 m, Indicated Resources û 300 m by 300 m.

Jan 1, 2009

By Wightman D, Hoyle M. W H, Peters W. S

The Radio Hill nickel-copper deposit is located 30 km south of Karratha. It is a new discovery in an area where similar mineralization had been previously discovered at Mt. Scholl and Ruth Well. Radio Hill is the first massive Ni-Cu sulphide deposit of economic significance to have been located in the Western Pilbara.Preliminary studies indicate that the sulphide mineralization occurs within gabbros, pyroxenites and peridotites of a basic igneous cumulate layered sequence. Primary sulphides have been subsequently remobilized and concentrated as stringer and massive mineralization. This is tentatively attributed to the intrusion of a further gabbroic body.The deposit appears to be of the gabbroic association type with a Ni:Cu ratio varying from 1:4 in the outer parts of the mineralized envelope to 1:0.9 towards the central zones. In drill core observations, chalcopyrite surrounding pyrrhotite was noted in many instances. Drilling has so far delineated a body developed over a strike length of 600 m and a horizontal width of up to 25 m. The mineralization plunges 20° to the southwest with a southerly dip varying from 75° in the west to about 20° - 30° in the east.The deposit is a leaf-shaped ore zone, plunging southwest from a vertical depth of 17 m in the north to 300 m in the south. The massive sulphides occur as lensoid masses within this zone. A geological resource of up to 2.5 million tonnes at 1.5 per cent Ni and l.4 per cent Cu is indicated.The predominant sulphides are pyrrhotite, chalcopyrite and pentlandite, with significant cobalt, platinum group metals and gold. Tellurides of Pd, Bi and Pb were detected by scanning electron microprobe within the pyrrhotite and other trace metals include Zn and native tin. Massive magnetite is sometimes associated with the massive pyrrhotite intersections.A test on one composite massive sulphide sample showed that pyrrhotite is present mainly as the non-magnetic hexagonal variety and only 10 per cent is present as magnetic monoclinic pyrrhotite.The deposit has no surface expression and its identification was based mainly Oil drilling targets generated by geophysical methods. No secondary minerals have been observed in association with the primary sulphides, even though the deposit is only 17 m below surface in the northern part.

Jan 1, 1987