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By G Harbort

The use of geological data for optimisation of operating plants has become a significant part of the modern process mindset. The underlying principle is to convert spatial geological data into metallurgical information to drive production and mine planning, blast design, blending strategies and plant set-up. Increasingly the process designer is required to interface with geological and mining staff to propose the best investment strategy for a project’s benefit.The geometallurgical model development for the Zafranal copper-gold project commenced in March, 2010, several months after the start of a major drilling campaign by AQM Copper Inc. The initial evaluation stage required review of historical Teck RC data to determine areas of metallurgical interest within the project. As drilling transitioned from RC to diamond drilling, core that was considered representative of the resource was selected and subjected to MLA mineralogy analysis. When coupled with sequential copper analyses this allowed calibration of an assay derived mineralogy model, allowing process concept options and a preliminary test program to be developed. This Phase 1 test program provided a preliminary process design, operating costs and anticipated concentrate grades and recoveries. Both this data and resource estimation were used to generate a preliminary Whittle pit optimisation based on maximising net smelter return, which in turn fed into a preliminary mine plan. The preliminary mine plan, in conjunction with geological logs and core results was used to develop a phase 2 metallurgical test program, where variability tests were conducted throughout the resource and composites formed to investigate specific years of the mine plan in locked cycle flotation. In addition comminution tests were modelled against geometallurgical domains allowing comminution components values to be calculated for 36?000 m of core. A flotation geometallurgical model was developed and incorporated into the resource model allowing concentrate grades and recoveries to be estimated on a block-by-block basis.

Sep 5, 2011

By S Utili, A Agosti

The Overall Slope Angle (OSA) of pitwalls plays a crucial role in the financial return of an open pit mine. In current practice, pitwall profiles are designed to be planar in cross-section within each rock layer, ie the profile inclination across each layer tends to be constant. A new slope design software, OptimalSlope, has been recently proposed to determine the geotechnically optimal profile shapes for the pitwalls of mines. OptimalSlope seeks the solution of a mathematical optimisation problem where the overall steepness of the pitwall to be designed is maximised for an assigned stratigraphy, rock properties (unit weight and strength) and Factor of Safety. The geometry of the benches is provided as input to OptimalSlope. The results obtained so far on three mine case studies in isotropic rock masses (Utili et al, 2022; Agosti et al, 2021a, 2021b) show that optimal profiles are up to 5° steeper than their planar counterparts – ie the planar profiles exhibiting the same FoS – leading to realising significant saving on waste rock and as a consequence Net Present Value increments and carbon footprint reductions. OptimalSlope algorithms have been modified to deal with anisotropic rock masses characterised by direction dependent shear strength. In the paper, the case of rock masses in banded iron formations (BIF) is tackled. A data set of anisotropic rock shear strengths typical of Western Australia is considered. The Snowden modified nonlinear model was employed to characterise the anisotropy of the rock mass shear strength. From the OptimalSlope simulations performed emerges that optimal pitwall profiles can increase significantly the Overall Slope Angle in comparison with planar profiles featured by the same Factor of Safety. LEM stability analyses of all the profiles were also performed by Rocscience Slide 2 to independently verify the FoSs of the optimal profiles obtained.

Nov 29, 2022

The Abra mineralized body is regarded as a significant new style of mineralization for its environment. It is a blind polymetallic deposit, located in the Bangemall Basin of Western Australia. It was discovered by Geopeko in 1981 by diamond drilling a coincident magnetic gravity target, which revealed a large low grade epithermal Fe-Ba-Pb-Ag-Cu-(AuW) deposit, hosted by chemogenic and clastic sedimentary rocks, overlain by 200-500 m of clastic sedimentary rocks, of Middle Proterozoic age. The mineralization occurs as an upper stratabound phase, and a lower vein "stringer" style phase within a pervasive chlorite alteration envelope.

Jan 1, 1987

Longhole open stoping was introduced in the zinc-rich 'B' lode at New Broken Hill Consolidated Limited (NBHC) during 1968. Since then one longitud- inal and a series of transverse longhole open stopes have been developed. The longholes are drilled using Gardner Denver airtrac drilling jumbos and the broken ore is loaded from drawpoints and transported to chutes using Wagner ST5 scoop- trams. The holes were drilled from sill stopes 160 ft apart. The width of an emptied transverse longhole stope was successfully widened by blasting rings of blastholes drilled parallel to the stope wall. Proposed stope and pillar designs for a series of transverse longhole open stopes were assessed using a method of finite element analysis, applied to a longitudinal section through the area. Blastholes have been surveyed for dip and bearing using an Eastman borehole survey camera. The data produced has provided the basis of a study of blast- hole deviation. Deviation of boreholes is considered to be the major cause of the formation of benches in longhole stopes.

Jan 1, 1971

By S Wan, F Zhang, J You, K Tang, X Tang, C Bessada, A Canizarès, Q Zhang, L Lu

Microstructure of CaO-SiO2-based glassy samples with various Al2O3 contents were examined quantitatively by Raman spectroscopy and 27Al MAS NMR (magic-angle spinning nuclear magnetic resonance). Sequence of multiple cluster models of aluminosilicate system modified with Ca2+ and Na+ cations have been designed, and Raman spectra simulation were carried out after geometric optimisation by quantum chemistry (QC) ab initio calculation. The functional relationship between Raman scattering cross-section (RSCS) and stress index of silicon-oxygen tetrahedron (SIT) for aluminosilicates was established, which was applied to the calibration of experimental Raman spectra. Some five-fold coordinated aluminium (AlV, around 5 per cent) and less than 2 per cent sixfold coordinated aluminium (AlVI) were detected by 27Al MAS NMR, while most of aluminium remained in tetrahedral sites (AlIV). The hyperfine quantitative results of Raman spectroscopy and NMR showed a gradually production of AlIV with addition of Al2O3, along with the significant adjustment of Qi species distribution, in which Q1, Q2 reduced and fully polymerised Q4 increased while Q3 showed a non-monotonic variation and obtained the maximum at Al2O3 = 18 mol per cent. Furthermore, the effects of aluminium to bridging oxygen bond types (T-Ob, T = Si, Al) and the degree of polymerisation were also discussed in detail. The evolution of microstructure and its correlation with the viscosity of CaO-SiO2 based melts, incorporating various Al2O3 additives, have been investigated by employing in situ high temperature Raman spectroscopy at 1823 K and viscosity model. These structural features related to composition are essential theoretic foundation to understand their properties. The average Qi evolution culminates in an overall enhancement of the degree of polymerisation. Viscosity was determined utilising a rigorously selected viscosity model, elucidating a consistent upward trajectory as Al2O3 content is incrementally added. Furthermore, a quantitative analysis of the relationship between viscosity and structure was conducted based on the average number of non-bridging oxygen per network-forming tetrahedron (NBO/T). It provides valuable insights for examining and predicting viscosity behaviour of aluminosilicate systems.

Aug 21, 2024

By H J. Dalstra

High-grade iron ore may be derived from banded iron formation (BIF) through four fundamentally different processes:1. syngenetic precipitation of chert free BIF,2. residual enrichment by removal of gangue minerals from BIF to form bedded (residual) ironore,3. mechanical erosion of iron oxide and chert from bedded iron ore or BIF and re-deposition andupgrading as detrital iron ore, and4. chemical removal of iron from BIF and precipitation elsewhere as a secondary (channel) irondeposit.Finally, the BIF itself may constitute iron ore if a high-grade concentrate utilised for pellets or sinters can be derived from it through mechanical (industrial) separation of iron oxide by means of crushing/milling and mineral separation.Historically, exploration for high-grade BIF hosted iron ores was focused on the residual (bedded) deposits and driven by supergene concepts. Exploration for detrital and channel type iron ores was mostly secondary to exploration for bedded deposits, but recently, a more focused exploration effort has led to the discovery of enormous moderate to low iron grade deposits in the Pilbara region of Western Australia. Exploration for high-grade iron ores using syngenetic concepts has been limited,but together with exploration using hypogene concepts offers the best hope of fi nding concealed deposits. Exploration for BIF sources suitable for concentrate ores commenced in the ‘old’ iron ore provinces after the high-grade resources were depleted and has only recently gained importance in Australian BIF provinces, mainly as a result of high iron ore prices in the last decade.

Jul 11, 2011

By J, T C. McCuaig, J Hodgkison, T Fouet

Olympic Dam is the eighth largest Cu deposit and the largest U deposit in the world, with approximately 35 million tonnes of contained Cu and 1.2 million tonnes of U. The most recent resource estimate was for 2.95 billion tonnes of mineralised material with average grades of 1.2 per cent Cu, 0.4 kg/t U, 0.5 g/t Au, 2.6 g/t Ag as contained mineral resources. Olympic Dam is expected to produce >200 000 tonnes of Cu and 4200 tonnes of U3O8 from 9.8 million tonnes of ore in 2004, making it the 12th largest Cu producer in the world. One of the impediments to achieving targeted rates of production has been oversize material (>0.9 m) reporting to stope draw points. A major contributor to oversize material may be overbreak along pre-existing structural weaknesses from stope walls and backs during the production life of a stope. Underbreaking to structures can also have a detrimental effect on the performance of a stope. In an effort to understand the influence of structural geology on stope performance, WMC Resources and SRK Consulting partnered during 2003 to refine the current system of structural mapping, and to use historical data to produce a structural interpretation covering a large part of the mining area. The interpretation has been wireframed in DATAMINETM into a three-dimensional structural framework model. To date, there are more than 600 structures of >50 m strike length incorporated into the structural framework model, which covers a study area 1500 m + 600 m + 350 m. A back-analysis exercise to assess the influence of interpreted structures on overbreak and underbreak was completed for laser-surveyed stopes.

Jan 1, 2004

By A Poliakov, E Donskoi, K Vining

The automated optical image analysis software Mineral4/Recognition4 (M4/R4) is capable of performing comprehensive characterisation of different materials throughout the iron ore value chain, including ore fines, lump, sinter, pellets and coke. It has been successfully used by CSIRO for industrial and research projects and has been independently licensed to several world leaders in iron ore production and ironmaking. The M4/R4 software was strongly integrated with a Zeiss microscope to make use of the company’s powerful AxioVision software. This required users to own both Zeiss microscope hardware and AxioVision software in order to be able to use M4/R4 to its full image acquisition and analysis capacity. Therefore, it was not available to the users of equipment produced by other major microscope manufacturers. In recent times however, Zeiss has indicated that the AxioVision software will no longer be supported. To overcome this limitation, CSIRO has proceeded with the next generation of this software, Mineral5/Recognition5 (M5/R5). Importantly, the M5/R5 system has been developed without any dependence on a specific microscope hardware/software platform. Furthermore, the image analysis functionality is now based on openCV open access software and has been fully rewritten using stateof- the-art software development tools to allow reading and processing of all major image formats. Although past applications have been specific to iron ore and ironmaking applications, other improvements, such as an increased number of minerals allowing better gangue segmentation, flexible mineral definitions, improved software modules behaviour and refined analysis routines enables the platform independent M5/R5 image analysis system to be used by researchers in any area of mineralogical or materials research.

Nov 8, 2021

By S C. Dominy

The Bendigo Goldfield is located in the state of Victoria, Australia, and is one of a number of quartz-reef fields that make up the greater Central Victorian Goldfield. At Bendigo gold particles are characterised by their very coarse nature, ranging from below 100 to over 10 000 ¦m in size. Some 60 per cent of the gold occurs in particles greater than 1000 ¦m in size. This characteristic ensures that the mineralisation is very challenging to both sample and evaluate. Diamond drilling provides a measure of geological structure, but is a poor measure of in situ grade, understating it by up to 75 per cent. Drilling combined with on-reef development, bulk sampling and geological interpretation has been used to define Indicated Mineral Resources. For grade control, a balance had to be sought between sample representivity, cost, turn around time and practicality. Sampling of extreme nugget effect deposits generally requires the use of bulk sampling in order to be representative. However, the cost and turn around time is significant. As a result, a 50 kg micro-bulk sampling system has been introduced that attempts to overcome these problems by providing a fast, practical method that can discriminate between ore and waste. As the mine passes into production, grade control will increasingly become dependent upon geological data collection and interpretation.

Jan 1, 2005

A research and testing facility has been developed at Simtars to allow the spontaneous combustion testing of coal on a large scale. In this adiabatic reactor, the coal particle sizing is closer to that which could be found in the goaf and therefore the reaction is more likely to simulate the underground situation. This allows aspects of the spontaneous combustion process and methods for detecting a heating to be investigated which cannot be done in an operational mine. Up to 18 tonnes of run of mine or crushed coal is loaded into the reactor and allowed to self-heat while the temperature and gas profiles within the coal pile are monitored. The gases evolved from the coal are analysed using a fixed gas monitor system and gas chromatography to determine which of the common mine fire indicators and ratios can be used to predict the onset and progress of coal heatings. Benchmarking of the inherent propensity of a coal to spontaneously combust at both the large- and laboratory-scale is also possible by comparing the sample against previously tested samples. It has been found that the coal particle size affects both the time it takes for the coal to react and the location of the developing heating. The heatings generate approximately one metre from the inlet but in the crushed coal case do not progress to an advanced heating stage until the æhot spotÆ migrates towards the coal surface where there is an increased oxygen supply. Physical properties such as the compressive strength of the coal also affect the heating size and the time it takes for a heating to develop. Higher strength coals appear to oxidise more slowly and therefore take longer to self-heat as oxidation of the coal is the heat-generating step in the spontaneous combustion process. The best indicators of the state of the heating were found to be CO make and GrahamÆs ratio which are independent of air flow. Investigation of a potential spontaneous combustion should begin as soon as the CO make or GrahamÆs ratio exceed the background levels. The results from the tests undertaken on a number of Queensland and NSW coals are reported here together with the implications for the mining industry.

Jan 1, 2005

HoistEM is a helicopter-towed time domain electromagnetic system. This paper presents details of the towed array structure (the Hoist) as well as a description of the instrumentation. A comparison between HoistEM and ground TDEM (from which HoistEM was derived) is given. Over 50 000 line kilometres of HoistEM have been completed to date and datasets for structural mapping, nickel, base metals, manganese, ground water and bathymetry are presented and discussed.

Jan 1, 2004

The future of the Tasmanian mineral industry can only be estimated from a knowledge of the past, and armed with this knowledge an orderly plan for the future can be developed. Brief mention is made of the major historical developments through to the present day, with past and future development areas clearly mapped. Areas of importance which have been discussed are divided into the mining of metals, fossil fuels and non-metals; and the process- ing and extractive industries. Discussion then follows on the current general non-insular pressures on the mining industry, the energy crisis, scrap, world shortages, new techniques, inflation, and the effects of exploration on the environment. This is then followed by a discussion of the advantages of Tasmania as a mining state and a cataloguing of the present exploration and some possible areas of future development. From this a suggested plan emerges for the future development of the Tasmanian mineral industry, to incorporate the latest technological advances and by planning to meet the challenge of survival and growth in a turbulent environment.

Jan 1, 1977

By A Gerdes, H BrStz, E GSbler, D Davis, F Henjes-Kunst, S Dewaele, T Graupner, T Oberthnr, M Sitnikova

Following the United Nations initiative to fingerprint the origin of conflict materials, the German Federal Ministry for Economic Cooperation and Development has decided to fund a pilot study on coltan ores. Since 2006, our working group has been investigating columbite- tantalite (coltan) mineralisation, especially in Africa, also within the wider framework of establishing certified trade chains. More than 300 samples were obtained from the worldÆs major coltan producing areas. Special attention is, however, directed to samples and concentrates from Ta-Nb-Sn provinces in Africa: Democratic Republic of the Congo, Rwanda, Mozambique, Ethiopia and Namibia. Using state of the art analytical tools, we investigate mineralogical and chemical parameters obtained from columbite-tantalite ores and concentrates in order to distinguish between ore provinces, likely even down to the deposit scale. Methods employed include fully automated electron microscopy (mineral liberation analysis), electron microprobe analysis (major and minor elements), laser ablation plasma-source mass spectrometry (trace elements and U-Pb dating), X-ray fluorescence spectroscopy (bulk major and trace elements), X-ray diffraction analysis (mineralogy and structure) and thermal-ionisation mass-spectrometry (U-Pb dating). Major and trace element concentration patterns, mineral assemblages in the ore concentrates, and zoning characteristics in the different pegmatites from Africa distinctly differ from each other. Furthermore, the following age populations are evident:Archaean (>2.6 Ga);Palaeoproterozoic (1.9 - 2.1 Ga);early Neoproterozoic (æKibaranÆ; 0.98 - 0.93 Ga); andlate Neoproterozoic to early Palaeozoic (ca 0.5 Ga). Currently, we focus on the resolution of the fingerprinting system from region via ore province down to deposit scale. Our preliminary analytical results indicate that a certification scheme including fingerprinting of sources of coltan ores is feasible.

Jan 1, 2008

By Muldoon T

Water sprays on mining machines are generally put there to reduce dust; however, research by the Bureau of Mines and others has shown that considerable airflows may also be generated by these sprays. This recognition of water spray-gen- erated air movement led to the "Spray-Fan" - a continuous miner auxiliary ventilation system which was shown to reduce methane peaks by a factor of 15. Recent successes and failures of the Spray Fan are reviewed. More recently, the same principles were used in the design of the "Shearer- Clearer" for reducing dust at longwall shearer operators. The original design was successful; however, a new design is now available which is more practical to install and does a much better job of holding the dust against the face downwind of the shearer. The latest research objective is to eliminate the negative impact of spray- generated air turbulence on continuous miner dust control. Most coal faces in the USA are ventilated in the exhaust mode using "line curtain", and the forward airflow on the side of the heading opposite the curtain is inevitably weak. Air turbulence generated by sprays which are incorrectly located and/or operated at excessive pressures can cause roll back - in which the dust cloud at the face is forced unwind against the ventilation and spreads over the miner cnerator. The general approach to reducing "roll back." is reviewed and art anti-roll back water spray system is presented.

Jan 1, 1983

By Shillabeer J

Paste backfill has been adopted by many underground mines in North America and a growing number elsewhere. Paste offers a number of advantages. This paper suggests wider applications of paste technology to surface tailings disposal and water management. Advantages include improved overall stability, potentially easier permitting, smaller water inventory and earlier reclamation. It may be feasible to use the same plant to prepare backfill and to dispose of surplus tailings. Example cost models are given to illustrate potential applications.

Jan 1, 1998

The Porgera gold mine has made significant progress with the successful installation of a JK FrothCam image analysis system. The system is used to measure and control froth velocity on the scavenger circuit which has brought significant economical and operational benefits. The froth velocity signal, determined by analysis of the camera, is transmitted to the PLC that manipulates flotation cell airflow rate and cell level controllers to maintain a target froth velocity of 130 mm per second. Following on from a three-week trial installation in June 2000, a permanent installation was commissioned on the scavenger Outokumpu (OK150) tank cells. Further work is in progress on the rougher Wemco cells. This paper describes the evaluation of FrothCam Technology and its subsequent installation.

Jan 1, 2003

DURING the four years, 1922, 1923, 1924, and 1925, China produced the following quantities of non-ferrous metals and ores: Antimony Products - 67,869 (long) tons. The production for 1925 was 20,869 tons, of which 80% was regulus, 14% crude,and 6% oxide.Arsenic (White) - 4200 tons. The production for 1925 was 1200 tons, but only 90 tons were exported, some 25% of which to Hong-Kong, France, and U.S.A. each, and the rest in small lots to other countries. Domestic consumption was 1110 tons, and thelocal price for "cake" was around £47 per ton on 1925 exchange.Arsenic Ore (Realgar) - 1400 tons.Lead Ore (Galena) - 44,853 tons. The production for 1925 was 10,853 tons, of which 16%, produced in Korea, went to Japan, and 84% produced in Hunan, went to Europe.Manganese Ore (Pyrolusite) - 142,567 tons. The production for 1925 was 42,567 tons, of which 94.3% went to Japan.Tin Ingot - 33,480 tons. In 1925 the exports to Hong-Kong were 8880 tons of usual rough tin of 94% to 96%. Most of this was refined to No. I Chinese quality of 99.3% and exported to U.S.A. and Europe, owing to the good price ruling.Sulphur - 12,000 tons. Sulphur is included in this list in order to explain how its production led to the discovery of some other ores.Wolfram - 19,668 tons. The production in 1925 was 5868 tons, most of which came from the Quee Mee mountain district in South Kiangsi, from the detrital deposits. Civil disturbances prevented the usual output from Hunan border.Zinc Ore (Blende) - 134,190 tons. Exports for 1925 were 34,190 tons of low-grade ore, averaging 30% zinc, 14% lead, and 7% silver...

Jan 1, 1927

By C M. Zammit, N Cook, F Reith, C L. Ciobanu, J Brugger

The role of biological agents in the gold mining industry is currently limited to the use of microorganisms in bioleaching and bioremediation. However, there is a variety of possibilities in which biotechnology could aid the mining industry in the future. In this article we discuss the potential for the development of these novel biotechnologies and the role they can play in the exploration for new gold deposits, the processing of ores and the post-mining remediation of sites. The development of these biotechnologies has been enabled by rapid advances in our molecular-level understanding of the role microorganisms play in the solubilisation, dispersion and precipitation of gold. An understanding of the distribution of microbial species in soils overlying mineralisation can be utilised to develop bioindicator systems that assist with gold exploration. An in-depth knowledge of how microorganisms interact with gold complexes is being used to develop in-field biosensors, supporting exploration. Processing technologies may be improved based on advances in our understanding of the interactions between microorganisms, ore minerals, cyanide and gold. For instance, cyanide-producing microorganisms are being investigated for use in in situ leaching of gold. In turn, the use of cyanide-utilising microorganisms for the degradation of cyanide is being explored. Combined, the implementation of these biotechnologies in the gold mining sector may revolutionise the industry, leading to greener, more efficient exploration for and extraction of gold.CITATION:Zammit, C M, Cook, N, Ciobanu, C L, Brugger, J and Reith, F, 2013. Possible future applications of biotechnologies in the gold industry - a prospective approach, in Proceedings World Gold 2013 , pp 233-244 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By Stephenson D. B, Burgess J, Burgess F. L, Marshall S. H

A new high intensity flotation process 'FASTFLOT' is explained and its theoretical advantages compared with other flotation systems are discussed. The results of initial FASTFLOT testing on the zinc roughing circuit at Pasminco Mining, Broken Hill South concentrator are presented and compared to recent plant data. The comparison suggests that on roughing duties, the FASTFLOT process yields superior concentrate grade while requiring less than one third the residence time of a conventional mechanical cell plant. Strategies for FASTFLOT deployment are also presented.

Jan 1, 1994

By B King

Processing expansion options and mining fleet purchases are major cost items that receive due focus in most cost management analyses. If these items are not needed, they can significantly reduce a project’s short-term capital spend and improve profitability and value to shareholders. When conditions change prior to purchasing equipment, the purchase may no longer represent the best decision for the project.This paper outlines a structured approach for making major cost decisions to improve the value of a project, determining which items should be kept and which should be eliminated.CITATION:King, B, 2014. Cost management optimisation, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 7–12 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014