Mining opportunities and risks in West Africa
Expert Opinion Article by:
John Kwofie, Principal Mining Engineer and Country Manager, SRK Consulting Ghana
Ivan Doku, Principal Resource Geologist and Country Manager-designate, SRK Consulting Ghana
Neil Marshall, Corporate Consultant (Geotechnical Engineering), SRK UK
James Gilbertson, Director and Principal Consultant, SRK Exploration Services
Vis Reddy, Managing Director SRK Consulting SA
Investment decisions are in general not based on the prevailing market environment, but rather on a long-term view of the market. This, together with a host country’s national policy framework on mining, underpins decision-making – with political stability a key factor.
In bulk commodities like bauxite, iron ore and manganese, a number of targets in the region have been generated through reconnaissance studies over the last decade. Not many have progressed to the project level, though, due to factors such as the quality and quantity of the product, and the lack of infrastructure for transportation and export of these bulk commodity products.
Social and environmental risks also weigh steadily heavier on mining companies operating in West African jurisdictions. Communities around mines are generally characterised by high levels of poverty, so the direct and indirect benefits of mining investment can be great. Among the challenges in many instances, however, are the legacy issues that become evident towards the end of a mine’s life.
Lack of legislative instruments – or a lack of effective enforcement of license conditions – may delay the effective implementation of community development initiatives. It may also curtail the necessary engagement between mining communities and miners on the issue of shared value. While communities welcome the possibility of investment, there is no ‘free ride’ for mining companies, who need to earn their social license to operate through consultation and commitment to agreements with local communities. Affected communities are also very concerned about environmental impacts and sustainability issues, both during the operational and post-operational phases.
On the technical front, risks are also considerable – but there is a growing array of technological opportunities that can be leveraged by experienced professionals. For example, most gold deposits in Ghana are structurally controlled and can be associated with weak shear zones, which can have a significant influence on the stability of pit slopes and underground excavations. Instability in mining excavations can be further exacerbated by factors like mining induced rock mass damage from drilling and blasting activities, inherent weakness in the oxidised saprolite horizon, the structural complexity of the area, and the influence of groundwater and high rainfall infiltration resulting in elevated pore water pressures. These issues tend to compound each other, with structural complexity resulting in planes of weakness and strength anisotropy in the saprolitic materials, and controlling groundwater flow volumes and directions often resulting in compartmentalisation of groundwater.
In addressing these risks, it is vital that the structural setting of the deposit is defined at an early stage in the life of the project. This allows for a robust geotechnical model on which to base the appropriate geotechnical guidance through all study stages.
Given the high cost of exploration core drilling, it makes good sense to maximise the quality of geotechnical and structural data collected at this early stage. For instance, detailed geotechnical logging can be conducted, while high quality and accurate structural data can be obtained using down-hole acoustic or optical televiewer systems. The additional upfront time and cost is outweighed by the significant value added to understanding the project’s geotechnical aspects. In terms of mine design, geotechnical design confidence can be increased with adequate geological, structural, rock mass and hydrogeological data acquisition to provide quality, representative design analysis data. This facilitates geotechnical optimisation of mine designs, providing significant value potential to mining projects and operating mines alike.
The right expertise, leveraged by modern technologies, can facilitate improved data confidence during and after exploration. Important ingredients include experienced professional site supervision and technical oversight, with standardised digital geotechnical core logging and database management.
Among other technologies available are the latest hyperspectral core imaging technology, digital photogrammetric modelling techniques for both terrestrial and drone mapping technologies, and augmented reality technology for geological and structural data.
Risk management remains the cornerstone of successful exploration and mining endeavours in the region, while embracing the opportunities that technology presents to add value to the experienced professional.