ORCID Profile
0000-0002-0638-3693
Current Organisations
University of Exeter
,
Curtin University
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Publisher: MDPI AG
Date: 29-04-2018
DOI: 10.3390/MIN8050186
Publisher: Springer International Publishing
Date: 30-11-2019
Publisher: MDPI AG
Date: 25-05-2022
DOI: 10.3390/MIN12060667
Abstract: The underground mining process typically results in some of the metal inventory remaining as a broken residue within mine workings. Up to 0.5 m of broken ore may be left on the floors of development drives and in stopes. It is possible that this broken ore contains 5% or more of the original metal in the ore reserve, which will have a material effect on reconciliation and project economics. Broken ore remaining in the mine may have been subject to enhanced milling during the mucking process, yielding enhanced liberation of the economic minerals of interest. Given that the material in question is already broken, the s ling strategy will be based on digging trenches or pits into the mine floor to extract a pre-determined mass of material for assay. The s ling of stope floors will most likely be based on grab s ling. Application of the theory of s ling is a key aspect of ensuring that evaluation is effective. Gy’s equation for the fundamental s ling error can be used to determine an optimum s le mass, and to inform subsequent steps in preparation for assaying at given confidence limits and precision. This paper presents a discussion and case study.
Publisher: MDPI AG
Date: 16-05-2023
DOI: 10.3390/MIN13050680
Abstract: Estimating the heterogeneity of base and precious metal mineralisation is a great challenge for mining engineers and geologists who undertake resource evaluation, grade control and reconciliation. The calculation of the minimum broken s le mass to represent a given lot of mineralisation at a given comminution size is based on the estimation of IHL, the constant factor of constitution heterogeneity. IHL can be derived by different heterogeneity testwork or calibration approaches. Three methodologies are well known in the mining industry: the standard heterogeneity test, the segregation free analysis, and the s ling tree experiment or duplicate s le analysis. However, the methodologies often show different results, especially when it comes to gold. These differences are due to many reasons. Assuming the variances added by s le preparation and analysis to be equivalent for all tests, the reasons for the differences may include the nugget effect (particularly the presence of coarse gold), the segregation effect and the procedure of collecting/splitting the s les when performing the tests. This paper analyses and compares two heterogeneity tests: the original heterogeneity test and the simplified segregation free analysis, both performed on mineralisation from different Brazilian operations. The results show clear differences between the tests, highlighting the complexity of estimating the heterogeneity of mineral deposits. The study reports the importance of using proper methodologies for constitution heterogeneity estimation so that minimum s le masses and relative standard deviations of the fundamental s ling error can be relied upon. It also provides recommendations for practitioners on the application of testwork/calibration studies.
Publisher: MDPI AG
Date: 12-2018
DOI: 10.3390/MIN8120560
Abstract: Geometallurgy is an important addition to any evaluation project or mining operation. As an integrated approach, it establishes 3D models which enable the optimisation of net present value and effective orebody management, while minimising technical and operational risk to ultimately provide more resilient operations. Critically, through spatial identification of variability, it allows the development of strategies to mitigate the risks related to variability (e.g., collect additional data, revise the mine plan, adapt or change the process strategy, or engineer flexibility into the system). Geometallurgy promotes sustainable development when all stages of extraction are performed in an optimal manner from a technical, environmental, and social perspective. To achieve these goals, development of innovative technologies and approaches along the entire mine value chain are being established. Geometallurgy has been shown to intensify collaboration among operational stakeholders, creating an environment for sharing orebody knowledge and improving data acquisition and interpretation, leading to the integration of such data and knowledge into mine planning and scheduling. These aspects create better business optimisation and utilisation of staff, and lead to operations that are more resilient to both technical and non-technical variability. Geometallurgy encompasses activities that utilise improved understanding of the properties of ore and waste, which impact positively or negatively on the value of the product, concentrate, or metal. Properties not only include those that impact on processing efficiency, but also those of materials which will impact on other actions such as blasting and waste management. Companies that embrace the geometallurgical approach will benefit from increased net present value and shareholder value.
Publisher: MDPI AG
Date: 29-05-2018
DOI: 10.3390/MIN8060232
Abstract: Grade control in underground mines aims to deliver quality tonnes to the process plant via the accurate definition of ore and waste. It comprises a decision-making process including data collection and interpretation local estimation development and mining supervision ore and waste destination tracking and stockpile management. The foundation of any grade control programme is that of high-quality s les collected in a geological context. The requirement for quality s les has long been recognised, where they should be representative and fit-for-purpose. Once a s ling error is introduced, it propagates through all subsequent processes contributing to data uncertainty, which leads to poor decisions and financial loss. Proper application of the Theory of S ling reduces errors during s le collection, preparation, and assaying. To achieve quality, s ling techniques must minimise delimitation, extraction, and preparation errors. Underground s ling methods include linear (chip and channel), grab (broken rock), and drill-based s les. Grade control staff should be well-trained and motivated, and operating staff should understand the critical need for grade control. S ling must always be undertaken with a strong focus on safety and alternatives sought if the risk to humans is high. A quality control/quality assurance programme must be implemented, particularly when s les contribute to a reserve estimate. This paper assesses grade control s ling with emphasis on underground gold operations and presents recommendations for optimal practice through the application of the Theory of S ling.
Publisher: MDPI AG
Date: 17-04-2019
DOI: 10.3390/MIN9040238
Abstract: Grade control aims to deliver adequately defined tonnes of ore to the process plant. The foundation of any grade control programme is collecting high-quality s les within a geological context. The requirement for quality s les has long been recognised, in that these should be representative and fit-for-purpose. Correct application of the Theory of S ling reduces s ling errors across the grade control process, in which errors can propagate from s le collection through s le preparation to assay results. This contribution presents three case studies which are based on coarse gold-dominated orebodies. These illustrate the challenges and potential solutions to achieve representative s ling and build on the content of a previous publication. Solutions ranging from bulk s les processed through a plant to whole-core s ling and assaying using bulk leaching, are discussed. These approaches account for the nature of the mineralisation, where extreme gold particle-clustering effects render the analysis of small-scale s les highly unrepresentative. Furthermore, the analysis of chip s les, which generally yield a positive bias due to over-s ling of quartz vein material, is discussed.
Publisher: IM Publications Open LLP
Date: 02-2022
DOI: 10.1255/SEW.2022.A3
Publisher: MDPI AG
Date: 04-05-2018
DOI: 10.3390/MIN8050193
Publisher: MDPI AG
Date: 10-10-2021
DOI: 10.3390/MIN11101109
Abstract: S ling, s le preparation, and assay protocols aim to achieve an acceptable estimation variance, as expressed by a relatively low nugget variance compared to the sill of the variogram. With gold ore, the typical heterogeneity and low grade generally indicate that a large s le size is required, and the effectiveness of the s ling protocol merits attention. While s ling protocols can be optimised using the Theory of S ling, this requires determination of the liberation diameter (dℓAu) of gold, which is linked to the size of the gold particles present. In practice, the liberation diameter of gold is often represented by the most influential particle size fraction, which is the coarsest size. It is important to understand the occurrence of gold particle clustering and the proportion of coarse versus fine gold. This paper presents a case study from the former high-grade Crystal Hill mine, Australia. Visible gold-bearing laminated quartz vein (LV) ore was scanned using X-ray computed micro-tomography (XCT). Gold particle size and its distribution in the context of liberation diameter and clustering was investigated. A combined mineralogical and metallurgical test programme identified a liberation diameter value of 850 µm for run of mine (ROM) ore. XCT data were integrated with field observations to define gold particle clusters, which ranged from 3–5 mm equivalent spherical diameter in ROM ore to mm for very high-grade ore. For ROM ore with clusters of gold particles, a representative s le mass is estimated to be 45 kg. For very-high grade ore, this rises to 500 kg or more. An optimised grade control s ling protocol is recommended based on 11 kg panel s les taken proportionally across 0.7 m of LV, which provides 44 kg across four mine faces. An assay protocol using the PhotonAssay technique is recommended.
Publisher: Informa UK Limited
Date: 19-06-2019
Publisher: IM Publications Open LLP
Date: 12-10-2021
DOI: 10.1255/SEW.2021.A41
Publisher: IM Publications Open LLP
Date: 12-10-2021
DOI: 10.1255/SEW.2021.A30
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Simon Dominy.