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Diagnostic gold deportment studies and leaching behaviour of small-scale gold mining tailings from eastern region, Ghana

Quaicoe Ishmael, Beyuo Martin, Quaicoe Solomon, Lasidzi Nikao A.

Journal of Sustainable Mining

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2023

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Vol. 22. iss. 2

81--88

EN

Artisanal and small-scale gold mining (ASGM) sector employs about 80% of the mining workforce but only contributes about 20-30% of Ghana's gold production. The low gold production is linked to low recoveries associated with the activities because of inadequate understanding of the chemical, mineralogical and metallurgical characteristics of the ores. This study examined the metallurgical characteristics of typical small-scale gold mining tailings to understand their grinding characteristics, gold deportment and cyanidation behaviour. The gold deportment results showed that 96.1% of the gold in the samples is free milling (can be leached directly with cyanide and recovered through carbon adsorption), whilst the remaining 3.9% of the gold in the samples is associated/locked up with other mineral phases (carbonates, sulphides, carbonaceous matter and quartz). The gold-by-size distribution also indicated that 73.1% of the gold is contained in coarser size fractions (+150 mm), 14.96% is from -150 mm to +75 mm size range, and 11.83% is contained in the finer size distribution (-75 mm). This suggests that incorporating a gravity recovery system during processing will be highly advantageous. The leaching kinetics results showed that gold recoveries achieved within 8, 16 and 24 h were 68, 73.8 and 76.4%, respectively. The corresponding total cyanide consumption rates after 8, 16 and 24 h of leaching were 550, 580 and 600 ppm, respectively. Generally, the gold recoveries and the cyanide consumption rates agree with industrial practices/results. Overall, the outcomes of the study support the view that some small-scale gold mining tailings are economically viable, and hence can be re-processed through efficient processes such as carbon-in-leach/carbon-in-pulp.

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“Small in size, but big in impact”: socio-environmental reforms for sustainable artisanal and small-scale mining

Owusu Obed, Bansah Kenneth Joseph, Mensah Albert Kobina

Journal of Sustainable Mining

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2019

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Vol. 18, iss. 1

38--44

EN

Artisanal and small-scale mining (ASM) - small sized, largely unrecognized, rudimentary, and an informal form of mining - occurs in more than 70 countries around the world and is mainly hailed for its socioeconomic benefits and reviled for its environmental devastation. As a result, many people are confused about the future of ASM. In Ghana, the government banned ASM in 2017 and formed a security taskforce drawn from the military and police to crack down on nomadic and local ASM workers who defy the ban. This approach is unsustainable, deals less with the fundamental problems, and increases poverty among the already impoverished local populations who depend on this type of mining as their only means of livelihood. To support the argument for sustainable reforms, revenue growth decomposition and growth accounting analyses were performed to determine the factors shaping ASM revenue over 25 years (1990-2016). Results show that production (gold output) is the most important factor that influences revenue growth from ASM, contrary to the usual view that the price of the metal is mainly responsible for the increase in revenue. Thus, increasing labor hours in ASM could significantly increase mining revenue, reduce unemployment, and improve local commerce. We strongly conclude that sustainable reforms such as increasing local participation in decision making, education and training, adoption of improved technology, strengthening regulatory institutions, legislation and enforcement of enactments, and the provision of technical support and logistics could ensure socio-environmental sustainability.

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Siting a centralised processing centre for artisanal and small-scale mining - a spatial multi-criteria approach

Amoah N., Stemn E.

Journal of Sustainable Mining

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2018

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Vol. 17, iss. 4

215--225

EN

Artisanal and small-scale mining is one of the global phenomena that is a threat to environmental health and safety. There are ambiguities in the manner in which an ore-processing facility operates. These ambiguities can cause environmental problems and hinder the mining capacity of these miners in Ghana. The vast majority of attempts to address these problems through the establishments of centralised processing centres have failed, with only a handful of successes. This research sought to use an established data-driven, geographic information based system to locate a centralised gold processing facility within the Wassa Amenfi-Prestea Mining Area in the Western region of Ghana. The study was designed to first determine the relevant factors that should be considered in the decision-making process for locating a centralised ore-processing facility. Secondly, it sought to implement the identified factors in a case study by identifying specific geospatial techniques that can best be applied to identify potential sites. By adopting in-depth consultations with four stakeholder groups for data collection and content analysis for data analysis, thirteen relevant factors were identified. However, in the case study, due to data unavailability, only seven of the factors were considered. Geoprocessing techniques including buffering and overlay analysis and multi-criteria decision analysis were employed to develop a model to identify the most preferred locations to site a centralised processing facility. Site characterisations and environmental considerations, incorporating identified constraints, to determine an appropriate location were selected. The final map output indicates estimated potential sites identified for the establishment of a centralised processing centre. The results obtained provide areas suitable for consideration.