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By W Valery, S Morrell

In the mining industry blasts are usually designed to fracture the in situ rock mass and prepare it for excavation and subsequent transport. The run of mine (ROM) fragmentation is considered good when it is fine enough and loose enough to ensure efficient digging and loading operations. Mining optimisation strategy is hence usually focussed on minimising total mining costs and maintaining these ROM fragmentation characteristics. Although this approach ensures an efficient mining operation it ignores the potential impact on crushing and grinding. Investigations by several researchers have shown that designing blasts to produce ROM fragmentation to optimise crushing and grinding performance enhances the overall efficiency and profitability (Eloranta, 1995; Kojovic et al, 1995; Bulow et al, 1998; Kanchibotla et al, 1998; Scott et al, 1998; Simkus and Dance, 1998). Field experimentation in this area is often found to be difficult because of high implementation costs and insufficient understanding about the effect of fragmentation at different stages in a comminution circuit. Modelling and simulation of blasting and comminution processes provide a more economic alternative to explore the impact of blast design changes on the down stream operations (Kanchibotla et al, 1998; Kojovic et al, 1998; Adam and Siddall, 1998; Bulow et al, 1998). However, the reliability of such simulations depends on:the ability of the models to reproduce the physical processes that take place; characterisation of rock mass in terms of its blastability and comminution characteristics; and in the case of blast modelling the ability to predict fines (-10 mm) has been found to be particularly important as this fraction has a significant effect on mill throughput.

Jan 1, 1999

By R M. Briggs

Kapowai Caldera Complex (KCC), located 10 km west of Tairua (eastern Coromandel Peninsula), is a late Miocene composite collapse caldera, formed during eruption of several small and large volume andesitic rhyolitic ignimbrites. Numerous epithermal Au-Ag mineral deposits and associated alteration zones at the KCC are related to caldera (rhyolite lava domes, intracaldera faults) or regional structures (faults). The main epithermal deposit exposed in the central KCC is associated with an E-W striking structural boundary fault that cuts the Welcome Jack rhyolite dome. Propylitic (calcite - chlorite) and sericitic (quartz - sericite) alteration haloes surround this deposit. Sporadic zones of sericitic alteration are also exposed within and on the margins of the Bulls Run rhyolite dome complex. Epithermal systems post-dated emplacement of these rhyolite domes, but were controlled by them. Propylitic alteration of ignimbrite in the floor of the Kapowai and Kauaeranga valleys is related to the major NE-trending Kapowai Fault which extends SW to south of Thames. Alteration along this fault pre-dates alteration associated with the rhyolite lava domes. Numerous sericitic and propylitic altered welded ignimbrite, rhyolite and andesite lava lithic fragments have been sampled from intracaldera ignimbrites, and although no direct source is known, they infer the presence of buried epithermal systems. Repeated epithermal activity at the KCC is inferred by the exposed epithermal deposits/alteration zones and the older buried geothermal systems. Silicic caldera volcanoes are considered to be critical volcanic environments for epithermal Au-Ag mineralisation in Coromandel, but are highly variable and need detailed stratigraphic, structural, petrologic, and geophysical studies to characterise them.

Jan 1, 1999

The Golden Cross mine is situated in a sensitive environmental setting on the North Island of New Zealand, about 150 kilometres south-east of Auckland and about 8 kilometres NW of Waihi. The mine is situated in dipping topography, with volcanic ashes making up soils, fault zones running through the area, and rainfall of about 3 m per year on average. Water management is the most demanding environmental challenge on site, and a comprehensive programme has been put in place to address tailings deposition, long term tailings storage, and water treatment during and after operations.   The tailings impoundment is built with an underdrainage system that collects groundwaters and waters that seep through the impoundment. The embankment and impoundment are both built to withstand the Maximum Credible Earthquake and the Probable Maximum Flood. Tailings are treated to remove cyanide and to decrease metal solubility to reduce long term risk to water quality after mining. A state-of-the-art water treatment plant is utilised to treat water from the underdrainage system and water decanted from the top of the tailings pond and stormwaters to remove residual cyanide and metals to extremely high standards with a great deal of reliability and at reasonable cost. Closure of the facility addresses long term post mining water quality issues, and rehabilitation of the area with wildlife habitat as a priority.

Jan 1, 1995

THE paper is principally eoncerncd with experimental work carried out the author whilst a number of the metallurgical staff at the Cockle Creek works. The metallurgical has been discussed sufficiently for the reader to follow the course of the experiments but the actual plant has only been described in so far as it effected metallurgical treatment, since the arrangement of such a smelter is a matter of common knowledge.The lead-roasting plant consisted of Godfrey roaster, Dwight-Lloyd maehines and Huntingdon-Heberlein pots. The usual treatment was in the Godfrey furnaces, followed by sintering in the Huntingdon- Heberlein pots. The paper is divided into two parts in the Godfrey furnaces and Huntingdon-Heberlein pots. An account of experiments on the utilization of the hood gases from the Huntingdon-Heberlein pots for acid making...

Jan 1, 1924

By G E. Ho, M Anda, S Dallas

Water auditing and water conservation measures are fast becoming the quantitative tools for water balance reporting in the mining and minerals processing sector. Therefore, this paper was written to describe the process of water auditing in a goldmining environment and to contribute towards building an appropriate water management framework for The Cooperative Research Centre (CRC) for sustainable resource processing (CSRP). The research will assist with the assessment of water balances in mining and hydrometallurgical processes and ongoing probabilistic modelling for Newmont Mining Corporation, its wholly owned gold mines, and its joint venture operation of Kalgoorlie Consolidated Gold Mines (KCGM). Kalgold or KCGM are the managers of a joint venture project between Barrick Australia (50 per cent) and Newmont Mining Corporation (50 per cent) at Kalgoorlie, Western Australia (WA). Boddington Gold Mine (BGM), Western Australia, will commence operations this year and manage the new goldmine expansion project. BGM is 100 per cent Newmont owned and will operate to continue mining gold and copper from the existing (BGM) site that was decommissioned in 2001.

Jan 1, 2009

By J G. Webster-Brown, K L. Brown

The Waihi Region is host to many low sulphidation epithermal Au-Ag deposits. The Golden Cross mine located at the head of the Waitekauri River, eight kilometres NW of Waihi, was a gold mining operation that placed significant emphasis on environmental management. An assessment of the influence of this mining project on stream sediment geochemistry (Fe, Mn, As, Cu, Pb, Zn, Cr, Cd, Ni, Ag and Se) in the Waitekauri Catchment has been made. Effective waste management during the mine operation appears to have prevented contamination of stream sediment. Trace metal concentrations in the Waitekauri Catchment sediment have generally decreased since 1987, and are currently mainly below the ANZECC (2000) sediment quality guidelines. However, elevated As levels were recorded in the Upper Waitekauri River and Battery Stream, exceeding guideline values. Elevated levels of Cu, Pb, Zn and Cd were found in the Huanui Stream, a tributary of the lower Waitekauri River. This reflects the influence of past mining operations in the valley, as well as natural weathering of hydrothermally altered Coromandel Group andesite. At a number of sites, Mn concentrations also exceeded sediment quality guidelines, and this may be derived from the remediated Golden Cross mine site.

Jan 1, 2003

Lead Removal from Contaminated Soils with Chelating Agents

Sep 13, 2010

Recovery of Pentlandite and Chalcopyrite from Tailings by Bi-Cyclone Powerful Flotation Column

Sep 13, 2010

A model has been developed as part of the AMIRA P420 Gold Processing Technology Project to simulate the recovery of gold by centrifugal gravity devices. The model (which is available online) uses the simulation methodology developed by Laplante et al (1995) to predict gravity recoverable gold (GRG) recovery under varying operating conditions and circuit configurations. In addition to predicting GRG recovery, the model also predicts the GRG content and size distribution of the cyclone overflow and underflow. The predicted overflow GRG content and size distribution can be used as inputs for a leaching model in which size dependent leaching rates are applied for each size class of GRG and non-gravity recoverable gold (non-GRG) in the cyclone overflow, allowing size-by-size leach recoveries to be determined for GRG and non-GRG. The application of the gravity model and leaching model are demonstrated using a case study. The simulated gravity recovery and leaching performance showed excellent agreement with the measured values. The developed models can be used to assess the sensitivity of gravity gold and leach recoveries to varying feed GRG content, GRG size distribution, gravity circuit feed rate, classifier performance and leach residence time. The described methods can be used to optimise new and existing gravity and leaching circuits.

Aug 1, 2010

By D Misra, R Ganguli, S Bandopadhyay

The objective of this paper is to assess the accuracy and applicability of recent state-of-art methods such as the machine learning algorithms (MLA) for mineral resource estimation. Conventional methods such as geostatistics have been predominantly used in the mining industry for this purpose with varying success. Recent advances in the use of MLA have provided a fresh approach to obtain improved accuracy in the estimation of mineral resources. Two MLA methods: the neural network (NN) and the support vector machine (SVM) have been used to estimate a polymetallic ore deposit in Alaska.The general characteristic of SVM and NN emphasises the fact that they can approximate any multivariate non-linear relation among variables. Although neural network models are able to capture the nonlinear spatial relationships that may be present in the data, they are usually difficult to optimise under sparse data settings. Of the various NN alternatives, despite their effectiveness, the model selection and estimation process is typically difficult as it involves solving complex integration and optimisation of parameters. In support vector modelling (SVM), estimating of parameters involves optimisation of a convex cost function. The working principle of SVM makes it robust against noisy and extreme value data. At the same time, it can capture the spatial distribution of ore grade more effectively with careful modelling and selection of SVM parameters.The outcome of the MLA methods were compared to those of the geostatistical ordinary kriging (OK) application to study their generalisation ability. The comparison was made using the following goodness of fit criteria: mean-squared error; mean absolute error; mean error; and coefficient of determination. The results indicated that the MLA methods may improve the predictability of ore deposits and thereby reduce the inherent risk in mineral resource estimation.

Sep 26, 2011

By K Williams, W Chen, J Miller

The flow function of an iron ore material governs its flowability characteristics in material handling chains within the resource industry. A uniaxial compression test is able to obtain a flow function more rapidly comparing to the Jenike direct shear test; nevertheless, the results often exhibit lower rankings using the former method. This study aims to investigate the fundamental stress states within the test specimen that lead to this phenomenon, and to introduce a new uniform density specimen preparation method for a uniaxial compression test, in order to achieve comparative flow functions as for a Jenike direct shear test. The minimisation of the wall friction effect and achievement of the critical state when preparing a uniaxial specimen are explicitly discussed. Experimental investigations on flow functions of a suite of Australian iron ore samples were conducted using both the uniform density uniaxial compression test and the Jenike direct shear test. Results from both methods were found to be comparable, providing the specimen exhibits cohesive flow behaviours. The outcome of this research enabled development of a rapid and reliable flow function testing method for cohesive iron ore materials.CITATION:Chen, W, Williams, K, Roberts, A and Miller, J, 2017. Rapid and reliable flow property testing – a modified uniaxial approach, in Proceedings Iron Ore 2017, pp 149–154 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By M Bilodeau, G Caro, R Beaudoin, D Labrie

In 2005, Dyno Nobel Canada Inc, DynoConsult and CANMET-MMSL used their pool of expertise in blasting, ground control, open pit and underground mining, mineral processing, information technology and applied mineralogy to launch a research project aimed at evaluating the role of electronic detonators in the development of a sustainable energy-efficient rock reduction process. The overall objectives were to improve health and safety in a mining environment and reduce energy consumption and greenhouse gas (GHG) production in the Canadian mining industry. The study was conducted in a quarry located in Nova Scotia, Canada, with the objective of taking advantage of the higher accuracy and flexibility of electronic detonators towards improving blast efficiency and measuring its impact on productivity in a quarry environment and energy savings. Optimising the blast sequence was the first aspect to be considered before starting to look at designing bigger blasts and achieving productivity improvements, without creating additional environmental concerns, as the quarryÆs location was representing a challenge in itself in the surrounding community. The use of high-speed cameras (500 fps) was an improved means of analysing blast dynamics during the firing sequence. Seismic monitoring and linear superposition techniques were also applied to validate the sequences to be tested in all three specific geological areas. The combination of field measurements allowed to identify the optimal blasting sequences that would then be delivered accurately with the electronic initiation systems. The data from 12 blasts (six with electronic detonators and six with pyrotechnic detonators) carried out in three different geological formations (soft, medium and hard rock) showed that the electronic blasting technology could increase rock fragmentation by 15 to 20 per cent. A more uniform distribution of rock fragment size was also obtained. Blast improvements on downstream processes resulted in a five per cent productivity increase in rock excavation and transportation, a ten per cent energy reduction in primary crushing and a 15 per cent increase in the primary crusher throughput. A prototype soft-sensor based on primary crusher data (eg energy consumption, throughput, feed and product size distribution) and a simplified computer process model were developed for online measurement of a rock operating work index. Furthermore, rock samples were collected and specimens were prepared in order to determine the tensile and compressive strength of the rock materials, evaluate the aggregate crushing work index and examine the development of micro and macro-fractures under binocular and scanning electron microscopy (SEM). Blast-induced rock damage was evaluated at the end of the laboratory testing program. A reduction in rock hardness by about 30 per cent was observed after blasting. However, the impact of the blasting method (eg using electronic versus pyrotechnic detonators) on the induced rock damage was either absent or not perceptible within the measurement technique accuracy and the number of samples analysed.

Jan 1, 2007

By D Craw, P Lindsay, B Peake

The geochemical properties of Kaiata Mudstone and Brunner Coal Measures are evaluated in order to determine their suitability for placement at the proposed Cypress and existing Stockton mines. Correct scheduling of this waste material is needed in order to prevent sulfide oxidation and the generation of acid rock drainage. The Kaiata Mudstone has both acid generating and acid neutralizing properties. Results from this study and previous research from Kingett Mitchell Ltd (2003), indicate that within the Kaiata Mudstone sulphur content decreases with distance away from the Brunner Coal Measure/Kaiata Mudstone contact, while calcium carbonate content increases; sulphur values range from 0.33 to 4.23 wt %; and the acid neutralizing capacity ranges from 0 to 10.4 wt %. The Brunner Coal Measures have a low capacity to neutralize acid and sulphur content is variable ranging from 0.25 to 3.5 wt %. Appropriate control measures are therefore needed for the Brunner Coal Measures and any Kaiata Mudstone within close proximity to its contact. Tests have been undertaken to develop a rapid field or laboratory procedure to define the potentially acid-forming from the non-acid-forming Kaiata material. Results indicate that paste pH, Net Acid Generation (NAG) and Carbonate Bomb tests are suitable. Results from the Carbonate Bomb Test show a strong relationship with the Acid Neutralizing Capacity (ANC) and the Net Acid Production Potential (NAPP), indicating that this method may efficiently determine non-acid forming material in the field within fifteen minutes. Ongoing research includes kinetic column and shake extraction tests. These tests will quantify what trace elements could be leached from the waste rock and provide information on the usefulness of alkaline producing products such as Bauxsol, Limestone and Cement Kiln Dust.

Jan 1, 2004

Technical Challenges in the Flotation of Molybdenite from Porphyry Copper Ores

Sep 13, 2010

Adsorption of Starch on Kaolinite Surfaces

Sep 13, 2010

Surface Chemistry of Iron Ore Throughout a Processing Plant

Sep 13, 2010

Improved roof control in high deformation tailgate environments has been achieved over the last decade through development of stiffer and increased capacity standing support products. æThe CanÆ is one such development, being a steel cylinder containing a weak cementitious fill, designed to essentially fold in upon itself whilst maintaining strength. A laboratory study to better define the relative load contributions of the steel cylinder and fill, the confining interaction between these components and most importantly, the potential impact of varying the steel and/or fill properties is described. This would enable the support engineer to ædial-upÆ the desired strength and stiffness properties and optimise the standing support design with respect to load capacity, stiffness, weight (handling) and cost. Design curves to optimise strength based on steel casing thickness, fill strength (confined and unconfined) and æCanÆ geometry were established. Scaled-down (one-third) samples were used in the test program and found to adequately reflect the loading behaviour of full-scale versions, thereby providing significantly greater scope for further product development at less expense compared with testing full-scale products.

Jan 1, 2005

By K Niyomjinda, B Etschmann

Chatree Gold Mine is currently the only modern day gold mine operating in Thailand, and is situated approximately equidistant from Chiang Mai in the north and Bangkok in the south. Environmental guidelines set by the Thai authorities require Chatree Gold Mine to achieve a Total Cyanide level of 20 ppm or less in the process plant discharge slurry stream prior to release into the tailings storage facility. This paper describes both the initial difficulties faced in achieving compliance on this limit utilising the conventional INCO SO2/Air cyanide destruction system and the subsequent process improvements initiated to both the leaching process and the standard INCO process to achieve the current compliance levels of approximately 99/100 shifts. Improvements were focussed on the dual aspects of reducing the formation of WAD cyanide and ferrocyanide species in the leaching circuit coupled with process changes to improve removal of the ferrocyanide species from solution during the cyanide reduction stage.

Jan 1, 2004

By Brotzmann K, Turner RE, Philp DK, Rusden RC

New approaches in the last decade have led to the supplemental use of raw coal as a direct energy source in several iron and steelmaking processes. The dependence on more expensive coke and electricity is being progressively reduced. The Technology Venture of Klockner Werke and CRA has pionered several of these developments and is pushing ahead to processes for scrap melting and direct smel- ting of iron where coal is the ONLY energy source. Such complex developments depend strong- ly on the experience gained in the simpler but related processes for coal use already in operation. The longer term implications of a successful coal-based direct smelting process for the world steel industry are substantial.

Jan 1, 1986

By J L. Mauk

The Favona low-sulfidation epithermal deposit in the Hauraki Goldfield is less than one kilometre southeast of the world-class Waihi deposit. The veins are hosted by Miocene andesite of the Waipupu Formation, have a total strike length of over 900 m, a vertical extent of at least 350 m and are on average 1-3 m wide. Individual veins have been traced for 200 m with vein widths up to 25 m. The dominant vein textures are massive, crustiform and colloform banded veins and vein breccias, with subsidiary textures including comb, zonal, flamboyant, lattice-bladed, ghost-bladed, microbotryoidal, feathery, ripple and dune, and mosaic. Quartz is the dominant gangue mineral in the veins at Favona. Accessory gangue minerals include pyrite, chlorite, adularia, illite, calcite, and apatite. Electrum is the only gold-bearing mineral and is associated with acanthite, tetrahedrite, pyrite, sphalerite, chalcopyrite, and rare galena. Whole rock geochemical analyses indicate that gold grades correlate with textures/vein types. The highest gold and silver grades are associated with vein breccias and banded veins, with the former containing 28 g/t Au and 136 g/t Ag on average. To date, veins with significant base metal sulfide minerals, and massive and crystalline quartz veins lack significant precious metals (Au and Ag), except for one banded base metal sulfide-rich vein at Favona. An overall zonation of the veins exists, with base metal sulfide minerals dominant at depth (1050 m RL) of the system are characterised by massive quartz veins.Fluid inclusions from a total of 31 quartz, amethyst, and platy calcite veins reveal homogenisation temperatures of ~190-250¦C, with final ice melting temperatures between 0.0 and -0.8. Ice melting temperatures correspond to apparent salinities of 18O value of the water that formed these veins is approximately -4.3 per mil, which is similar to meteoric water-dominated, near neutral chloride fluids in geothermal systems in the Taupo Volcanic Zone.

Jan 1, 2002