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By J. L. Broadhurst, S. Rumjeet, S. T. L Harrison, T. Chimbganda

Post-mining land use for the production of industrial crops has the potential to mitigate environmental and socio-economic impacts of mine closure and stimulate post-mining economic growth. Fibre-rich plants are of particular interest due to their multi-product potential. In the South African context, where there are many abandoned and end-of-life mines near human settlements, an opportunity presents to assess the feasibility of transforming post-mining land into productive land and building resilient communities through the development of multi-product value chains from fibre-rich plants such as kenaf, hemp or bamboo. This paper provides an overview of the plant selection criteria, phytoremediation potential and the downstream options for the recovery of products and value from bast fibre plants (hemp and kenaf) and bamboo. Based on findings from a comprehensive review of the published literature, as well as interviews with relevant experts within South Africa, it appears that bast fibre plants are the best downstream option for producing ‘green’ textiles and high-end niche products, whereas bamboo is more suitable as a replacement for conventional timber. Although fibre plants have the potential to extract metals from soils, high concentrations may inhibit plant growth and affect the quality of the final fibre product. Further site-specific studies would thus be required to select the best route for both land remediation and optimal product recovery. Keywords: Bioremediation, bamboo, kenaf, hemp, multi-product value chains, sustainable postmining land use

Jan 1, 2020

By R. Uwaoma, A. Goosen, R. Matjie, K. Mphahlele, J. Bunt

Coal properties that are associated with wear and damage of grinding equipment during pulverization prior to combustion were investigated. A South African Highveld feed coal and its beneficiated fractions were crushed to <1 >0.25 mm particles for the grindability tests. These particles were milled and screened into <75 μm and >75 μm fractions, which were analysed by different techniques to establish a correlation with the conventional Hardgrove Grindability Index (HGI). The <1.5 g.cm-3 float fraction, which contained 93 vol.% (mineral matter free) total -macerals,9% kaolinite, and had the lowest HGI (57) (hardest to grind) was pulverized for 15, 30, 60, and 120 minutes for particle size distribution analysis. This analysis indicated that the content of <75 μm particles increases with increased grinding time. The >1.9 g.cm-3 sink fraction, with the highest HGI (76), 44% kaolinite, and 20 vol.% total macerals, was ground easily to generate the highest proportion of <75 μm particles. Based on higher correlation coefficients (R2 = 0.77–0.91), the ash yield, mineral matter, petrographic composition, and fixed-carbon have significant effects on the HGI. Conversely, the inherent moisture and total sulphur (R2 = 0.48–0.62) have only minor effects on the HGI. Results from this investigation could be implemented in the preparation of a suitable pulverized fuel with little equipment wear, as well as utilizing mineralogical and petrographic compositions. Finally, the effect of microlithotypes and maceral types in South African feed coals on the HGI should be investigated in further pulverization and grindability studies.

Jul 5, 2023

By A. C. Lawrence

A new approach to the -study of human factors in stope productivity by A. C. LAWRENCE B. Econ., D. Com. (S.A.) (Member) The extent of the improvement in mean performance which could be achieved by reducing the variance between stoping gangs is examined, and it is shown that a worthwhile gain would result if variance were reduced by as little as 5 to 15 per cent. The problem of identifying human factors which contributed towards variance in gang performance was examined in one gold mine. A total of 342 &apos;observations&apos; on 49 stoping gangs were gathered, each observation consisting of a set of figures for 36 variables for one gang for one week. The variables included &apos;stope factors&apos; such as face length, &apos;gang factors&apos; such as the ethnic composition of the gang, and &apos;supervisory factors&apos; such as the experience of the miner. These variables were related to &apos;tons trammed per week&apos; as a measure of work performance. The findings showed that certain of the predictor variables accounted for 66 per cent of the variance in gang performance and about two thirds of this could be attributed to gang and supervisory factors, that is to the &apos;human factors&apos;. The method suggests a basis for a new approach to the identification of human factors and is a promising step towards optimizing gang performance.

By P. Ramsaywok, S Ndanduleni, G. Legodi

The objective of this paper is to share the optimisation journey of a pilot Reflux classifier (RC) circuit in the Exxaro GG1 plant, at Grootegeluk beneficiation complex in Lephalale, South Africa. The RC circuit was commissioned in 2016 to produce semi-soft coking coal at its fines circuit; however the stability of operation as well as the quality control of the coal product was not fully achieved. Various test campaigns and optimisation studies were conducted to understand and optimise the RC circuit at GG1. The studies revealed circuit design inefficiencies; provided an improved technical understanding of the current pilot circuit and the parameters required for the circuit to reach a stable operation. The operation was stabilised with its current inefficiencies to produce an average 12.5% ash semi-soft coking coal product for sustained periods, above the initial target of 10.3% ash. Keywords: Reflux classifier, coal

Jan 1, 2020

By J. G. M. Mukoya, B. Adebayo

"This work was carried out to determine the influence of rock properties and drilling machine parameters on the penetration rate at the SJ pit of Rössing Uranium Mine, Namibia. Rock properties (uniaxial compressive strength, tensile strength, and modulus of elasticity) of samples collected were determined in the laboratory. Drilling experiments were conducted in which feed pressure, air pressure, rotary speed, weight on the bit, and torque were varied to measure their effect on the penetration rate. The uniaxial compressive strength varied from 90–180 MPa for layered marble-quartzite and banded gneiss. Increases in feed pressure, weight on the bit, and rotary speed beyond the optimum level led to a decrease in penetration rate and caused the drill bit to ‘stall’. Results of the study revealed that penetration rate increases with an increase in the feed pressure and air pressure. After reaching a maximum value, the penetration rate begins to decrease despite increasing feed pressure. A very high torque causes the drill bit to stall, since the feed pressure is too high and the air pressure is not sufficient to remove the cuttings from blast-hole at maxium bailing velocities. The average penetration rate varied from 19 to 45 m/h for phase 2 of the pit, and from 17 to 68 m/h for phase 3. The optimum drilling machine parameters obtained in phase 2 and phase 3 were slightly lower than those currently being used at the mine. The trials of the optimum machine parameters will assist in reducing the cost of drilling, which varied from N$29.48 to N$36.31 per metre for the tricone bit. IntroductionDrilling and blasting contribute most to the operational cost in opencast mining and have the potential to influence the cost of downstream operations (Aipanda, 2011). The drillability of rocks depends not only on the rock properties, but also on the drilling tools and operational variables. In rotary drilling, rotational speed, thrust, and flushing are the operational variables, and are known as the controllable parameters. Rock properties and geological conditions are the uncontrollable parameters. Although, many attempts have been made to correlate drillability with rock properties, the rock characteristics affecting rotary drilling have not been entirely defined (Hartman, 1962; Kahraman, Bilgin, and Feridunoglu, 2003). The drill bit is forced into a rock surface from the rotary power head, hence creating stresses and cracks at the bit-rock interface. The performance of a particular bit in any formation i"

May 1, 2019

By D. Borman

The location of underground positions in mines has usually fallen to their survey department&apos;s. Their usual tasks include: ? installation of a high-precision peg network like the National Survey grid as beacons ? offset measurements to the sidewalls, and sometimes hangingwall and footwalls, of development tunnels and excavations ? offsetting of stoping panels for the calculation of face ? advance and the square meterage of area removed. Other departments build their observations into the plans produced by the surveyors. If more precision is required, they ask the surveyors to `elevate&apos; their points with a theodolite. Apart from the survey peg network and `elevations&apos; these measurements are usually planer measurements suitable for producing plans, sections and projection sheets. When the only representation medium was a sheet of paper or transparency, this was perfectly suitable. However the development of CAD models of the workings has changed all this. Full 3D representation is not properly catered for in the tool sets in current use, and needless hours are spent converting analogue-type observations into digital form. The basic survey models need to be augmented by the observations of other disciplines that are also required to locate positions underground. These include: ? the need for geologists to plott their mapping and ? borehole logs into 3D space ? the need for samplers to position their sample points accurately because the geostatistical models are biased and inaccurate ? the need for stoping width recorders to position their thickness observations to prevent errant evaluation and bonuses ? the need for rock engineers to place their mappings into 3D to build true geotechnical models to manage geotechnical stresses ? the need for production officials to receive updated face ? positions during the month so that they can manage the ? production and utilize their resources properly. This paper covers a new method of positioning profiling points to a suitable degree of accuracy. I believe the method is sufficiently simple and cheap for all to use. Historical methods Platinum and gold orebodies, especially in South Africa, are generally narrow tabular deposits. This made them suitable for depicting on a 2D medium like paper. The determination of stoping or face widths was not a problem, as the ore is removed in a single stoping process. Such 2D representations could be easily positioned using tape offsetting between survey pegs or points tied in from survey pegs. Problems of dip were handled by using &apos;Stope Sheets&apos; which chose a best fit projection for the whole area depicted or by using true dip section sheets for inclined tunnels. Rolling reef and potholes were the common areas of difficulty. Most mines now model their orebody and plan the extraction in computer graphics. This means that the representation of the current workings has to change to support this trend. It now becomes a truly 3D problem. Mining officials find it inconvenient to have their actual workings in single-line depictions while their orebody is depicted with top and bottom contacts and the planned tunnels in 3D shapes. Geological models which form the basis for the resource model and planning process are often out of date, as the updating process is slow. The geological mapping has to be plotted onto sections and plans. These are then digitized into graphics by a draughtsman and checked by the geologist. Only then does the interpretation and model update take place. Potential methods to create 3D &apos;Actuals&apos; Global positioning systems (GPS) Surface mines have been blessed by the advent of GPS technology. These simple-to-operate pieces of equipment and compatible software make it possible for all types of mine employees to locate themselves, and therefore to locate their observations. GPS are often inexpensive and give an acceptable degree of accuracy. Only in deep pits or close to the highwalls are observations hindered. Such technology cannot however, work underground. Ground penetrating radar (GPR) GPR is reported to be very useful for estimating the positions of potholes and faults. However it is still considered as providing an estimate, not a definite measurement. GPR is good for seeing into solid rock, not into open spaces. Inertia reading devices Experiments with inertia reading devices have been conducted on the mines. They were the forerunners of GPS for military guidance systems, and were even used for city navigation in the early 70s. They do however work best with heavy or fast-spinning gyros. Anglogold Ashanti&apos;s attempt to use them were discontinued in the mid-90s when the developers asked for an additional few million rand for a device that would weigh more than 12 kg and have a limited operational life.

Jan 1, 2006

By P. Malíková, I. Osičková, R. Sousedíková, P. Rys, J. Dvořáček, S. Heviánková

Each mining project goes through the same life-cycle, from prospecting and exploration to closure and post-closure periods. This prompts the question whether the closure of a mine constitutes the end of its life-cycle or whether the decommissioned mine can be employed for some other purpose. Best-practice references indicate that there are many viable options. In our opinion, the production of service water is one such option. Laboratory research was carried out on the water from a flooded underground coal mine in Ostrava- Karviná coal district, Czech Republic, concerning the production of service water from pumped minewater. The research proved the practical feasibility of service or process water production. Given the effect of global climate change with regard to water resources, good prospects for this additional resource can be assumed since the water has to be pumped in any case for safety reasons.

Oct 1, 2022

By B. P. Watson, D. Hoffmann, D. P. Roberts

Potholes on the Merensky and UG2 reefs in the Bushveld Complex occur as near-circular to elliptical depressions or slumps on the reef horizon, normally presenting as severe disruptions which prevent economic extraction. Within the pothole, the reef and other strata may either be attenuated, absent, or highly deformed, this being the result of the overlying hangingwall strata having slumped down. The hypotheses for pothole formation involve several mechanisms, including downward erosion, upward fluid movement, or synmagmatic deformation. When potholes are exposed in mine workings, significant fracturing is often observed. This fracturing is particularly evident in anorthosite rock types. Stress measurements were conducted in a pothole on the Merensky Reef to determine if the fracturing was due to high stress conditions. The paper describes the measurement results and numerical modelling that was done to determine the influence of depth and mining on the stress condition at the site. The results show that high stresses do exist in at least some potholes, and that current formation theories do not adequately explain the measured stresses. In support of understanding the high local stress associated with the pothole, the study explored several rock engineering modelling processes to validate the conditions of the study site and enclosing excavations. A better understanding of the stress conditions in potholes with additional data could lead to more appropriate support design and avoidance of potential rockbursts in these structures.

Jan 1, 2021

By L. Aspola

The platinum group metals (PGMs), i.e. ruthenium, rhodium, palladium, osmium, iridium, and platinum, are typically found in association with each other, but also importantly, with nickel and copper. Typically Platinum and palladium have the greatest economic significance and other PGMs are typically produced as co-products of these. With recent increases in the value of nickel, cobalt, and the PGMs and an ever increasing focus on the sustainable use of metals, interest in the processing of secondary feed material sources and metal-bearing residues has also substantially increased. As an efficient, proven, and environmentally sound technology Outotec Ausmelt Top Submerged Lance (TSL) Technology has gained commercial acceptance in the nickel industry, including PGM recovery. For the processing of nickel- and PGM-bearing feed materials, five Outotec Ausmelt Furnaces at four sites are in operation. Two of these furnaces are located in Rustenburg, South Africa, which is by far the biggest mine-based producer of platinum. Outotec also has hydrometallurgical processes available for further treatment and extraction of PGMs, which are also briefly discussed.

Jan 1, 2012

By P. J. K Leeuw, E. Uludag, M. J. Nong

Efficient drill-and-blast performance is pivotal to the profitability of deep-level mines, where high operating costs and declining grades demand maximum throughput. This study investigated persistent fragmentation problems at a longhole stoping operation that suffered from simultaneous oversized rock blockages in 300 mm × 300 mm grizzlies and excessive fines. Fifty-one muckpile images from five blasted stopes were analysed with Split-Desktop. Although the overall F₈₀ was 287 mm, nominally suitable for the grizzly aperture, the Rosin- Rammler uniformity index of 0.80 revealed a highly inconsistent size distribution containing both boulders and fines. Existing drill patterns were then evaluated with the Aegis underground software, which showed negligible crack overlap at the toe owing to inadequate spacing and burden. Insufficient energy overlap between blastholes, particularly at the toe, was found to contribute to the coarse fragmentation, while excessive fines were attributed to the crushing and severely fractured zones of blastholes. Optimisation simulations demonstrated that an 89 mm blasthole diameter on a 2 m × 2 m pattern would overlap, aligning with Aegis requirements of balancing powder factor, break angle, and energy distribution. Implementing this revised pattern is expected to reduce secondary breaking, prevent ore-pass blockages, lower fines, and ultimately improve overall production efficiency. The methodology illustrates how integrated image analysis and modelling software can effectively diagnose and address fragmentation issues, particularly in underground longhole mining, where challenging blasting conditions require a balance between achieving optimal fragmentation and maintaining stope stability. This approach offers a cost-effective pathway to improving comminution performance in deeplevel mines.

Oct 2, 2025

By R. Altındag, D. Akbay

The point load index is a simple, fast, and inexpensive method for determining rock strength and can be applied both in the field and in the laboratory. There are, however, some disadvantages and limitations to the method, and the test results can be affected by the person carrying out the test, the rock characteristics, or the test device. In this study we describe an investigation into how the point load index value is affected by the shape of the conical platens used in the test. Point load index tests were carried out using different devices fitted with conical platens of different spherical radii, and on a modified device which circumvented the limitations/disadvantages. It was seen that the point load index value increased as the platen radius increased, as expected. In the case of testing using non-standard conical platens, an equation is proposed to normalize the point load index value with respect to the standard spherical radius value.

Nov 1, 2021

By A. Lebedev

Application of dynamic simulation for a base metal processing plant is discussed. The plant receives ore of variable quality from two pits and blending had to be applied to maximise recovery. The plant employs multiple stage crushing, screening, dense media separation, two-stage milling, flotation and further filtration. Stockpiles and bunkers are used in the plant to cater for breakdowns and operating delays, the latter being appropriately incorporated in the model. A detail dynamic simulation model was constructed from the rock face to the filtration plant to assist the plant design, notably with definition of the ore blending method, sizing storage capacity and in-plant conveyors. The plant model was broken down to capital equipment items and various feed types and mass balances were tested to ensure that the production target is met. The dynamic simulation tested the proposed blending method, identified bottlenecks, produced risk profiles for all strategic storage facilities and overall helped minimise the project risks and improve confidence in the plant design. Keywords: Dynamic simulation, ore grade, blending, capacity, risk profile, throughput, utilisation

Jan 1, 2020

By N. de Koker, Y Jooste, J. Gerber

This paper presents a novel application of the boundary element method for numerical modelling of the seismic activity and hazard that is associated with the shaft pillar extraction at Bambanani mine in South Africa. In the numerical model, the tabular mining excavations are represented by displacement discontinuity elements, and to accommodate crush, shear, and fault slip seismic events, the numerical model is populated with additional displacement discontinuity elements that represent modelled crush- and shear-type failures in the rockmass. Crush-type failures are evaluated by applying the limit equilibrium method and a Hoek-Brown strength criterion, and shear-type failures are evaluated by applying a Coulomb-friction strength criteria to Ortleppshear and geological features. In this paper, the modelling results are presented as time history analyses of modelled potency from 1 January 2010 to 30 June 2022 and normalised exceedance rates for different mining periods using an upper-truncated power law. The normalised exceedance rates of seismic events that have moment magnitude Mw ≥ 1.0 are lowest for the initial mining period (26 events per year) and highest for the final mining period (218 events per year). The relative errors of the modelled potency and normalised exceedance rates are typically less than 10% or 15%, which suggests that the modelling methodology is appropriate for medium- and longer-term forecasting of seismic activity and hazard, as presented in this paper. Shorter-term forecasting is not considered in this paper.

Nov 24, 2025

By F. Dinter, S. A. C. Hockaday, Q. G. Reynolds

The thermal decomposition of carbonate minerals as pre-treatment before smelting reduces the energy requirement for smelting. It can also make the combustion of fossil fuels for heating unnecassary. Thermal decomposition may become important in reducing greenhouse gas emissions when producing ferromanganese alloys while simultaneously reducing electrical energy demand during smelting. A kinetic reaction rate model for the thermal decomposition of manganese ores is presented, based on published reaction rate kinetics for the decomposition of manganese oxides and calcium carbonate. The model was validated against thermogravimetric data for two carbonaceous manganese ore samples and one ferruginous manganese ore sample. The reaction rate model shows that carbonate minerals in the manganese ores are decomposed at temperatures above 900 °C while pyrolusite is decomposed at temperatures from 450 °C to 500 °C. Mn2O3 decomposes rapidly at 550 °C. Braunite decomposition at temperatures below 1000 °C was negligible. The presence of organic carbon in the samples led to further reduction of the samples during thermal treatment.

Aug 3, 2023

By Dave Deglon, Andrévan der Westhuizen

Objectives ?Survey typical Met Accounting streams at the Zincor refinery ?Determine Precision in Metal Conc?s Measurements for Monthly Met Balance ?Determine the Components of Variance in these Met Acc Values (Sampling, Preparation, Analyses) ??Common plant practice? should be mirrored even though not always in perfect agreement with ?laid down procedures? or ?good practice? ?Mass Measurement and Inventory Measurement was considered in less detail ?not reported here

Jan 1, 2005

By K. Duffy, W. Valery, L. Pyle, P. Holtham

A conceptual scoping study was conducted to investigate pre-concentration options for upgrading ore from an Ag-Pb-Zn deposit. The low grade of the ore would result in only modest economic returns, given current market conditions. Several pre-concentration options were considered. These included: selective mining, crushing and pre-screening (following either standard or high intensity selective blasting), bulk ore sorting, particle sorting, jigging, dense medium separation, or combinations of these approaches. Flowsheets were developed for each option, and the upgrade performance was modelled using Limn to determine mass balances and stream tables. Due to the limited availability of test work data, the models were based not only on what test data was available but also on case study data found in the literature. The Bazin technique was used to derive assay by size data for different streams following crushing. Equipment lists and preliminary layouts were established based on the stream tables, and capital and operating costs were estimated for each flowsheet. This information was used to carry out a preliminary economic evaluation using net present value and sensitivity analysis. In this case, the most economically attractive process was found to be particle sorting; although further benefits may be realised by combining with bulk sorting. This paper describes the methodology used and the key findings of the study. Keywords: Pre-concentration, pre-screening, ore sorting, jigging, Ag-Pb-Zn, particle sorting, bulk ore sorting

Jan 1, 2020

By O. Dahl, B. Musuku, N. Schreithofer

Recovery of fine pentlandite is proving to be a challenging task in the Kevitsa sequential flotation operations, with over 60% of the nickel losses reporting into the -25μm size fraction. Since commissioning, the Kevitsa process has undergone major changes to address throughput and flotation performance. Major changes were implemented in the configuration of the milling and flotation circuits as well as in the operating conditions and reagent regime. Some of these changes improved nickel flotation while others deteriorated flotation performance. Most of the changes have had a direct impact on nickel flotation. This paper reviews the systematic analysis, laboratory testing and salient changes done to the process with special focus on the impact on the fine pentlandite flotation. Keywords: Blending, Flotation, Chalcopyrite, Pentlandite, Fines

Jan 1, 2020

By Q. Liu, S. Liu, Y. Cui

To reduce the frequency of mining incidents and improve safety and production efficiency, it is important to develop technology for the autonomous positioning and navigation of mining equipment, without the assistance of satellite navigation signals. In this study we review the current technological environment for positioning and navigation underground and present several integrated navigation strategies. Existing underground positioning and navigation technology is described, and the performances of different methods based on this technology analysed and compared. The combination types and positioning effects of underground positioning and navigation strategies are discussed. Recent research directions for filtering methods and positioning estimation algorithms for underground positioning and navigation are reviewed. Finally, we summarize the future direction of underground positioning and navigation technology and related algorithms.

Jun 1, 2021

By J. D. Steenkamp, J. Muller

"Excavation of an industrial-scale submerged arc furnace, utilized in the production of silicomanganese, identified two high-wear areas in the refractory lining: the tap-hole, built with cold rammed carbon paste and SiC bricks, and the hearth, built with cold rammed carbon paste. To obtain insight into the potential causes of wear, thermodynamic calculations were conducted on eight sets of data, obtained for seven furnaces on three plants based in South Africa. FACTsage software and associated databases – FACTPS, FToxid, and FSstel – as well as the Mn-Fe-Si-C database of Tang and Olsen (2006), were applied. Theoretical indications are that chemical reaction between carbon refractory and slag, as well as dissolution of carbon and SiC refractory in metal, contributed to tap-hole refractory wear; and dissolution of carbon in metal contributed to hearth refractory wear. IntroductionDuring the excavation of a 48 MVA submerged arc furnace (SAF) used for silicomanganese (SiMn) production, it was found that the taphole and hearth were high refractory wear areas (Steenkamp, 2014). In both these highwear areas, carbon-based cold ramming paste formed the hot face refractory lining (crucible). The wear profile of this SAF is presented in Figure 1.The hot face refractory lining was formed by cold ramming of high-grade carbon ramming material. This material consisted of 50–70% anthracite, 15–25% graphite, 6–12% resin, 2–7% tar, 1–5% clay, and 1–5% alumina. The tap-hole was built using SiC bricks, consisting of 75% SiC, 23.4% Si3N4, 0.3% Fe2O3, 0.3% Al2O3, and 0.2% CaO.In the tap-hole area, the wear of the SiC refractory material was estimated at 0.4 t, and that of the high-grade carbon ramming material, at 1.9 t (Steenkamp, Pistorius, and Tangstad, 2015). The amounts of slag and metal tapped during six years of operation of the tap-hole (September 2007 to April 2013) were estimated at 33 088 t (Steenkamp et al.,2015) and 41 360 t, respectively."

Jan 1, 2016

By T. Bui, T. Wallmach, S. B. Blancher, A. Back, M. Pierre, V. Delarue, A. Kanzari

This study investigates nickel laterite porosity and its impact on geometallurgical modelling. We performed a detailed mineralogical study on a set of Ni-laterite samples originating from New Caledonia. Samples were analysed after heavy liquid separation by automated SEM (QEMSCAN®). Laboratory and QEMSCAN® modelling results do not correlate well. Ideal physical mineral properties such as mineral densities used in QEMSCAN® modelling do not match the actual physical densities of minerals. The presence of empty or water-filled pores can represent important amounts in minerals and change the overall density of a particle. An adequate modelling of real density separation of minerals and particles should consider the water-filled pores. The first step towards a better simulation was to integrate pores larger than 10 μm in diameter filled with water (density of 1 g/cm3) in the QEMSCAN® database. The results approached, but did not match the physical laboratory results. The second step was to identify nanometer to micrometer sized pores, which could not be identified by QEMSCAN®. It was possible to identify nanometric pores in enstatite, Fe-oxides, serpentine, talc and quartz, and radial aggregates of fibrous Fe-oxyhydroxides with high resolution SEM (HR-SEM). The quantification of those micro-sized pores was performed on 2D HR-SEM images using image-processing techniques developed in Python to calculate the nanometer to micrometer scale pores in each mineral. Despite the limitation of converting 2D imaging into 3D objects, in our case pore sizes and porosities, we were able to calculate a mean value of porosity for each mineral. The integration of this porosity in the calculation of particle densities yielded a good match between the QEMSCAN® model and the laboratory experiment results. Despite the complexity of a strongly weathered material, such as Ni-laterites, a good knowledge of the ore makes it possible to build reliable processing models. Keywords: Mineralogy, geometallurgy, nickel laterites, SEM, QEMSCAN®, porosity, density

Jan 1, 2020