Search Documents

By R Trueman

An improved ability to predict dilution for narrow vein deposits enables more accurate economic comparisons between mechanised longhole stoping and other narrow vein mining methods, as well as reducing uncertainty surrounding dilution estimates for deposits at the prefeasibility/ feasibility stage. This paper proposes narrow vein dilution prediction and minimisation strategies for both greenfield sites and operating mines, respectively. The narrow vein dilution method (NVD method) is a tool for more accurately predicting longhole narrow vein dilution. The method is based on a new concept called benchmark stoping width. Benchmark stoping width is based on probabilistic analysis of overbreak distributions from a typical longhole narrow vein mine. The premise for the NVD method is that dilution associated with longhole stoping can be predicted using the benchmark stoping width. In addition to dilution prediction, the NVD method also includes strategies for narrow vein dilution minimisation generally, including; filling, cablebolting, stress relaxation, extraction sequencing and blast overbreak.

Jan 1, 2008

By M Yadav, K Clode, S Daykin

The mining industry faces numerous challenges related to sustainability and circular economy principles, necessitating strategic approaches to innovation and resource management. As demands for mineral resources continue to rise, mining companies are under increasing pressure to address environmental impacts, minimise waste generation, and optimise resource utilisation. These challenges underscore the importance of Research and Development (R&D) roadmaps as strategic tools for guiding innovation and sustainability efforts within the sector (Jochen Berbner, 2022). A design-led methodology offers a structured approach to R&D roadmap development, emphasising stakeholder engagement, collaboration, and alignment with industry objectives. By leveraging design principles, mining companies can ensure that their R&D initiatives are responsive to evolving challenges and opportunities, fostering a culture of innovation and continuous improvement. Against this backdrop, the project aims to address the pressing challenges associated with sustainability and circular economy in the mining industry. Through the development of R&D roadmaps and the application of a design-led methodology, the project seeks to identify innovative solutions for enhancing resource efficiency, minimising environmental impacts, and promoting sustainable practices within mining operations. This paper highlights the collaborative efforts among Isle, the mining industry, and water utilities, which have yielded tangible benefits. The study demonstrates how the outcomes from the roadmaps outlined below effectively align research with strategic objectives, fostering innovation to address pressing challenges.

Sep 1, 2024

By Henley S

The year 2000 is not very far ahead - only five years. It should not be hard to forecast what will happen between now and then, because the technologies that will be in practical use then should all be at least in embryo existence now. There has been a historical trend for the mining industry to work ever more difficult and ever more marginal deposits. There are clearly a few exceptions and major discoveries, but the industry is becoming heavily dependent, at both the exploration and the mining stages, on technological innovation to retain acceptable profit margins. With the new exploration and mining technologies come requirements for additional computing support. Computing technology further allows the potential integration of a wide variety of different types of data to help the explorationist to build and test exploration strategies, or to help the miner to design and schedule mining operations.

Jan 1, 1995

By L O. Filippov, Q Dehaine

Variographic analysis, a classical tool from the Theory of Sampling (TOS), can address practical situations with multiple variables; however, its application has very often been limited to one variable at a time. Recent developments have shown the benefits of using multivariate approaches for variographic characterisation of a set of variables instead of considering individual variables sequentially. Among these approaches, the multivariogram has been revealed itself to be a powerful tool when the overall time-variability of a process must be summarised in terms of a large set of properties (variables) to assess its true global variability. However, even when choosing the properties of interest carefully, the resulting global variance obtained with this approach may be very high. In particular, some variables that contribute to a major proportion of the global (multivariate) variability could be less important for the process performance than others having a lower variability. To address this issue, a new approach is proposed, combining the multivariogram with process modelling and multivariate data analysis methods such as partial least squares (PLS) regression from chemometrics. An example from the mineral processing industry is presented, for which the process performance could be linked to key process variables (sensor data) using the PLS regression. Once introduced in the multivariogram equation, PLS model parameters (loading-weights or regression coefficients) can be used to weigh the variables according to their relevance for the process. In addition, this also permits characterisation of process performance variability with time using only the process input variables and a weighted metric according to the PLS regression model. Ultimately, this method helps to find an optimised sampling procedure in terms of frequency, sampling mode and number of increments according to the actual overall process performance. This approach has potentially many applications in the mining, feed and food, pharmaceutical or any other industry for which it can be used to reduce risks and ensure a better use and management of resources.CITATION:Dehaine, Q, Filippov, L O and Glass, H J, 2017. Optimising multivariate variographic analysis with information from multivariate process data modelling (partial least squares regression), in Proceedings Eighth World Conference on Sampling and Blending , pp 381–390 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

The Calypso geothermal field, mapped by the R V Sonne (cruise SO-135) in 1998, includes four main sites, the Northern Vent Area (centred on 37¦ 36.7'S, 177¦ 06.2'E, area 1.5 km2), Central Vent Area (37¦ 39.4'S, 177¦ 05.2'E, 1 km2), Southern Vent Area (37¦ 41.7'S, 177¦ 06.0'E, 1 km2) and Mercury Vent Area (37¦ 41.3'S, 177¦ 07.3 'E, 0.5 km2). Hydrothermal activity at the vent sites is controlled by minor, sub-parallel NE-trending normal faults. Gas bubble trails (C02) and shimmering hot water vent from fractures and joints between large blocks of silicified volcaniclastics and in depressions in the sediments at the base of these outcrops. Measured maximum vent temperatures are between 180¦C and 201¦C. Venting fluids are at, or just below, boiling for water depths of 200 m. Rock samples recovered by dredge from the sites include massive anhydrite, clay-altered pumiceous ash, silicified volcaniclastic sediments and volcaniclastic breccias cemented by sulphur. Clay-altered samples, dominated by randomly interstratified illite-smectite and accessory chlorite, indicate formation environments of 70¦C to 90 ¦C. Native sulphur is abundant throughout the samples. Fine-grained (<1 mm) disseminated pyrite and vein pyrite occurs in the clay-altered pumiceous volcaniclastics and argillites. In the Southern and Mercury Vent Areas, fine-grained orpiment, realgar and cinnabar have deposited in the sandy matrix of volcaniclastic breccias. Amongst the cinnabar, small (<2 mm) beads of native Hg formed on the surface of several rocks following their recovery. These samples also contained abundant light hydrocarbons, which coat the rocks with an oily sheen.

Jan 1, 1999

Large scale rhyolitic volcanism is an important process at some convergent plate margins because it leads to chemical differentiation of the upper.-crust and is responsible for the production of long lived near surface thermal anomalies; the Taupo Volcanic Zone is.a Quaternary example. The main features of the magmatic systems-of the zone. are the existence of large high level chambers containing homogeneous silicic magma which erupt at intervals of thousands to tens of thousands of years. Geochemical work on the deposits resulting from these eruptions has shown that with few exceptions the magmas have been remarkably uniform in their . composition throughout the history of the zone although individual batches with lifespans of the order of. one hundred thousand years can be recognised by subtle differences in trace element ratios. Basalt is a rare proportion of the rocks exposed at the surface but has played a major role as a medium for heat transfer and as an end member in chemical mixing processes.

Jan 1, 1987

By E C. Holloway

"The financial valuation of mining assets has a number of fundamental differences to the valuation of many other asset groupings. One such difference is that typically, the greater proportion of both the cost and revenue sides of the cash flow are inherently governed by systemic market forces.As a result, the range of outcomes for the valuation of each mining asset is more unpredictable, with higher levels of risk and uncertainty. In contrast, the management function of many other non-mining businesses or industry groups can control at least a portion of the cash flow by maintaining the margin or controlling the sales price. The management teams of mining businesses and operations typically have limited options, and are thus price-takers for both costs and revenues. As mining is an inherently cyclical industry, large, long-life operations can exist through several price cycles, making valuation both subjective and challenging.The outcomes of both static- and stochastic-based valuations, as well as the internal probabilities of the associated cash flow statements, are significantly impacted when the correlations between the appropriate parameters are quantified, modelled and incorporated into the valuation framework. The appropriate parameters for correlation modelling primarily include those that are governed by systemic market forces. Applying this process results in a different risk profile for the asset by allowing the risks resulting from systemic market movements to be more accurately quantified and then objectively minimised. This process also reduces the level of residual uncertainty in the valuation outcome.This paper presents a valuation methodology to pragmatically incorporate this level of valuation sophistication and statistically quantify the associated increase in the level of confidence of the valuation outcomes reported.CITATION:Holloway, E C, 2016. Correlated valuation methodology, in Proceedings Project Evaluation 2016, pp 181–200 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

The ultraviolet spectrum of isopropyl ethylthionocarbamate (the principal constituent of Dow flotation collector Z-200) in water and of Z-200 itself in water was found to have an absorption peak at 242 nanometers(nm). The height of this peak was found to be directly proportional to isopropyl ethylthionocarbamate concentrations up to 15 p.p.m. Z-200 contains about 90 per cent isopropyl ethylthionocarbamate and the heightof the peak was proportionately lower, but obeyed the straight line relationship up to 15 p.p.m. This showed the potential value of spectrophotometric measurements for the determination of Z-200 residuals in flotation liquors.Methyl ethyldithiocarbamate (an impurity in Z-200) increased the peak height slightly, but other impurities in Z-200, xanthates, and most inorganic salts present in flotation liquors do not interfere. However nitrate ion and thiosulphate ion have absorption peaks which overlap the isopropyl ethylthionocarbamate peak.The simplest general method to overcome this effect is to extract the isopropyl ethylthionocarbamate into cyclohexane and to measure the absorbance of the extract.The maximum absorbance of the cydohexane extract was at 247 nm and the peak height at this wavelength was found to be directly proportional to the isopropyl ethylthionocarbamate or Z-200 concentration in the original aqueous solution. An alternative method is to measure the spectrum of the original aqueous solution using the aqueous raffinate from extraction as a reference solution. This gives the spectrum due to isopropyl ethylthionocarbamate alone and measurement of the absorbance at 242 nm gives the concentration in the original aqueous solution. Both methods give the same value for the concentration of isopropyl ethylthionocarbamate in the original solution.

Jan 1, 1969

By D R. Lueking

A technology involving separate unit processes for the generation and use of ferric ions for the oxidation of sulphidic minerals has been developed. The technology utilises a stand-alone automated bioreactor for ferric-ion generation (termed SAAB-FIG) and produces a low pH, ferric ion-rich leach liquor with a high oxidation potential. This leach liquor is then employed, in a separate unit process, to oxidise sulphidic minerals and regenerate ferrous iron that may subsequently be recycled to the bioreactor for the continual generation of ferric ions. The technique was successfully applied for the recovery of copper from chalcocite (Cu2S) and chalcopyrite (CuFeS2), as well as other ores and concentrates containing copper sulphide minerals. Coarse ore, ground ore and concentrates were treated with acidic solutions containing 8 to 12 (g/L) Fe(III) ions at a variety of temperatures. This process yielded over 50 per cent of the contained copper from both chalcopyrite and chalcocite samples. Maximum reaction rates and copper recoveries were found to be highly dependent upon temperature and pH and leach liquors containing bacterial cells displayed little difference in their leaching efficiency when compared to cell-free leach liquors.

Jan 1, 2000

Zinc-bearing materials containing chlorides and fluorides of alkali metals, such as electric arc furnace dusts, Waelz oxides, galvanising ashes, brass foundry and converter fumes are marginally attractive, both technically and economically, for processing by the Imperial Smelting Process or in a conventional zinc sulphate electrolytic plant. The EZINEX« Process allows the recovery of high purity zinc in cathode form from these materials, together with regeneration of the leach liquor. The process is based on a new electrochemical system which depolarises the anode reaction with reduction of the cell voltage, compared with the traditional sulphate electrolysis method. The electrolyte, based on a chloroammino complex, permits the recovery of other valuable metals present in the zinc bearing materials such as lead, copper and silver. These are recovered as a metallic cement, consequently improving the economics of the process.

Jan 1, 1993

Gold deposits in Eastern China have characteristic of belted distribution. The concentrating belts of gold mineralization are about parallel to the island are belt in Western Pacific Ocean. Gold deposits are mainly concentrated in the aged metamorphic rock series on the upwarping zones and upwarping fault zones, and obviously controlled by the deep fractures and their deriva-tive secondary faults. Gold mineralization had genetic relation to the Mesozoic (especially Yanshan period) magmatic activity. The distribution and genesis of gold deposits can be explained by the assumption of wavy structure. The formation of wavy structure is related to the process of Pacific plate and India plate.

Jan 1, 1990

By C J. N Wilson

The central Taupo Volcanic Zone is a region of intense Quaternary silicic volcanism accompanying rapid crustal extension. Modem central TVZ is the most frequently active and productive silicic volcanic system on Earth, erupting rhyolite at c.0.28 m3 s-1. The rhyolites show no major compositional changes with time, but the total extent of magma chamber zonation has changed with the advent of rifting and crustal extension at c.0.7 Ma. At least 34 caldera-forming ignimbrite eruptions have formed a complex sequence of relatively short-lived, nested and/or overlapping volcanic centres in central TVZ. Taupo contrasts with other large silicic magmatic systems in the exceptionally high frequency, but small size, of caldera forming eruptions. This contrast reflects the thin, rifted nature of the TVZ crust that precludes the development of long term magmatic cycles at Taupo. Within central TVZ, non-rhyolitic compositions have been erupted apparently irregularly in time and space; in particular there is no evidence for a geographic separation of basalts from andesites. TVZ is a rifted arc, but its segmented nature, high thermal flux and voluminous rhyolitic volcanism make it unique on Earth.

Jan 1, 1995

By R Talebi

A research project to better understand the rock mass behaviour and the seismic response has been conducted during the design and construction of the 9215 level at the E-Block sector of the Northern Star Kanowna Belle Mine. The research program was undertaken at a tunnel located 1100 m below the surface with the results applicable to feasibility studies on underground mining projects in highstress conditions, where failure can occur very soon after tunnel construction. Semi-circular excavation shapes coupled with the use of de-stress blasting techniques were designed to monitor the excavation in conditions of very high stress. The ground support was designed considering high energy dissipation ground support schemes (HED) as described by Arcaro et al (2021). The results indicate a decreased rock mass demand due to the change of excavation shape. Also, localised reduction in rock mass stiffness was achieved due to the implementation of de-stress blasting. Finally, increased ground support capacity was gained by the implementation of the high energy dissipation ground support schemes. The Kanowna Belle Mine has significant ore reserves at depths exceeding 1000 m below the surface. The results of this research will be used to optimise the extraction of the remaining E Stoping Block at depths exceeding 1350 m.

Mar 29, 2023

By D Roldpo, M Vidigal, J F. C L Costa

The local cumulative distribution function (lcdf) of a selective mine unit (SMU) can be estimated by conditional simulations using the statistics derived from the sample points, generating multiple equally probable scenarios. Conditional simulations permit the evaluation of the lcdf at any support, taking into account the spatial variability, ie the variogram, and the two statistical moments, mean and variance, of the conditioning samples. The SMU ore losses and dilution depend on the mining method and mining equipment selectiveness that, in its turn, depends on the predicted block size. A new approach to predict ore loss and dilution was developed in this study. Monte Carlo simulation is used to randomly generate a grade value derived from the lcdf at the mining stage (Zs_mc(t)) in order to make a decision about the SMU destination, ie processing plant (ORE) or waste dump (WASTE). If Zs_mc(t) is lower or equal to the cut-off (Z_cut-off) the block is ORE and, conversely, if Zs_mc(t) is higher than the cut-off (Z_cut-off) the block is WASTE. Considering these binary destinations ORE/WASTE, at the mining time t, and combining each realisation of the simulated random function Zcs_i (X), there are four possibilities for each SMU simulated value: 1. the block was simulated as ore and is actually ore (OO), 2. the block was simulated as ore and is actually waste (OW),3. the block was simulated as waste and is actually ore (WO), and 4. the block was simulated as waste and is actually waste (WW).The dilution factor is given by possibility 3 (WO), while the ore loss factor is represented by possibility 2 (OW). These results comprise the classical classification and reconciliation plots used in the mining industry. The new procedure proposed in this paper is based on the use of all the equally probable simulations to define the ore loss and dilution factors. An application of this methodology was carried out at Vale's iron mine in Brazil. The grade of silica was simulated and 50 multiple equally probable 3D models were generated. The mean and the standard deviation of the ore tonnage (OO + WO) for the 50 realisations, was 233 Mt and 0.5 Mt, respectively. The mean grade increased for the diluted ore (OO + WO) as well as their respective coefficient of variation (CV). The CV increases from 62 per cent in the undiluted ore (OO), to 101 per cent in the ore, considering the dilution factor (OO + WO). The mean ore loss (OW) was 10 Mt and the waste tonnage dilution (WO) was 9 Mt.

Jan 1, 2009

By Paine GG

In coal mining each of the unit operations are interrelated with each preceding operation having an effect on subsequent operations. This presents difficulties for determining when the lowest overall costs for a particular mining system are achieved. Drilling and blasting is the first mining operation for production and is known to have an effect on the subsequent loading, hauling and crushing operations. Computer blasting models developed over the past 15 years can be used to describe the drilling and blasting operation. This paper describes the ICI Blasting Model "SABREX" in detail. Methods of using the model are discussed. This involves field measurements of geological structure, shallow refraction seismic surveys, laboratory measurements of rock properties and high speed photography of blasts. The predictions are compared with actual blast results for fragmentation sizing and muckpile profiles. Outputs from the model are described and these can be used for input to models of subsequent operations.

Jan 1, 1987

The Court rejected the suggestion that CRAE had actively misled DMR concerning the worth of its tenements. The Court agreed that CRAE remained silent about certain significant information concerning CRAE's own tenement area. It was a significant question as to what duties CRAE'was under, given that it was in joint venture with DMR in respect of one of the tenement areas. Did that joint venture create an obligation on CRAE to disclose everything it knew? The Court said no. The Court said that the fiduciary duties were defined by the terms of the farm-in agreement between DMR and CRAE. When the Court examined the disclosure obligations within the confines of the contract, it held that CRAE had not breached those terms.

Jan 1, 1990

By S Lush, R Polglase

McConnell Dowell is pleased to be given the opportunity to present two papers to this conference. The first is a general discussion paper on our work in the field of slurry transportation. The second will be a technical paper on the development of a welded coupling compatible with urethane lined pipework. We trust that by discussing our recent work we can leave two lasting impressions on you: the versatility and useful role of slurry transportation, and the leading role taken by New Zealand in this technology This paper discusses three recent projects the New Zealand Steel Ironsand Transfer Line the Coarse Coal Ship Loading Technology the Nerang River Sand By-pass System. These have followed on from the other slurry projects with which McConnell Dowell has been associated such as the ironsand export trade at Waipipi and Taharoa. The New Zealand Contractors Federation awarded the Construction Award for 1986 to McConnell Dowell for the Ironsand Slurry Pipeline.

Jan 1, 1986

By D Bradshaw

The recovery of molybdenum at Kennecott Utah Copper (KUC) has become increasingly important as its demand and price have risen dramatically in the last few years. Consequently, the flotation behaviour of the molybdenum bearing mineral, molybdenite, has received a significant amount of attention. The flotation performance of molybdenite generally lags that of the copper sulfide minerals and is much more variable. There are many factors including particle size, liberation, surface slimes and oxidation that contribute to this and also much speculation as to the relative contribution of each of these factors. This paper discusses the morphology of the molybdenite found at KUC, the mineral associations in the different lithogical ores types and the effect that each of these has on flotation performance. Quantitative mineralogical analysis and an assessment of particle shapes are used to explain that flotation behaviour does not necessarily follow expected trends and that some behaviour is counter-intuitive. This unique behaviour can be explained by the morphology and anisotropic nature of molybdenite.

Jan 1, 2008

By K Guilfoyle

AngloGold Ashanti Australia Ltd operates an underground mine below a large open pit at the Sunrise Dam Gold Mine near Laverton in Western Australia. Operations are based on an extensive mineralised zone which has very complex geometry, has a high ‘nugget effect’, and is difficult to interpret and model. Initial underground ore was produced from relatively narrow orebodies dipping from 15º - 70º. Open stopes aimed to selectively extract high-grade ore, using methods including jumbo stripping and longhole drilling and blasting. The complex geology makes it difficult to accurately locate development and stopes in the positions required for profitable production. In narrow stopes, rock mass damage and overbreak dilute ore grades and increase the cost per ounce of gold poured. In flat orebodies, several different techniques have been used to recover blasted ore but overall productivity is low. Thus selective mining can also be slow, costly and recovers only a portion of the available mineral resources. Large longhole open stopes with cemented paste backfill are used to extract multiple zones of mineralisation from the Cosmo and GQ orebodies. Bulk emulsion explosives and electronic detonators are used in all large stope blasts to reduce the risk of misfires and to accurately control blasthole initiation sequences and delay timing. Larger stopes improve productivity and significantly reduce direct mining costs, enabling the use of lower economic cut-off grades which increase the overall recovery of mineral resources. This paper reviews the evolution of open stoping at Sunrise Dam, the various mining methods and drilling and blasting practices used, the results achieved, and the lessons learned.

Nov 8, 2011

The hoisting system at the Newcrest Telfer mine is designed for a final duty of 7.35 million tonnes per annum at a hoisting distance of 1450 m. In terms of hoisting capacity (t/h) times hoisting distance it is one of the largest friction hoist installations. Initially, the hoist will be equipped for hoisting 6.5 Mtpa from 1100 m depth. This new drive technology is now well proven by ABB for mine hoist applications with the first installation in commercial operation since July 2001. To date 17 systems for medium voltage drives and another five for low voltage drives have been purchased from ABB for mine hoists. This paper will also deal with skip design and powerful data loggers with diagnostics for local and remote monitoring that are installed in the Telfer mine hoist.

Jan 1, 2005