Part of our investment strategy is focused on exploration drilling and Ore Reserve development to grow the Mineral Resource and by converting these, we expand the Ore Reserve. The process involves identifying the best group of drill targets and prioritising those that have the highest potential to be advanced first.
We have developed a system – Exploring for value (E4V) – to ensure that our exploration activities are focused on maximising value to the business and that ensures ounces are delivered into the business plan and ultimately brought to account. In order maximise value, we had to establish a system that goes beyond the SAMREC code and allows us to bring into play at an early stage, very low confidence material in order to ensure that our exploration pipeline can deliver into our life-of-mine plans at the right time and at the right level of confidence. This system allows for the capture of geological understanding from the earliest stage of development. In addition to integrating our E4V process with our life-of-mine planning, we have also integrated with our project stage-gate process and our accounting standards.
In this integration, as an area is explored and drilled a series of stage-gate reviews and appropriate economic studies are used to justify the next level of exploration. The size of the area naturally controls to an extent the scope of the study for example a large greenfields discovery will require a full series of studies moving from early stage scoping to a conceptual study and ultimately all the way to a feasibility study, if it passes the hurdles between studies. Each of these steps, matched with a required level of confidence in the material to be mined, will undergo a defined stage-gate review. In the case of a small underground extension in a brownfields operation the studies would be infinitely less detailed but would still be required. These processes ensure that funds are not expended on areas that do not meet business plan requirement or potentially add value as produced ounces.
Targeted investments during the year led to two positive advances, with Pure Gold Mining achieving first gold production at the Madsen mine redevelopment in Red Lake, Ontario, and Corvus Gold continued advanced exploration at their projects in Nevada and published updated PEA (define) studies for the North Bullfrog and Mother Lode projects. AngloGold Ashanti actively monitors for new early stage opportunities that have the potential to be a fit for our company portfolio should the exploration programmes for the projects prove to be successful.
Greenfields exploration aims to discover large, high-value Mineral Resource, which will eventually lead to the development of new gold mines.
During 2020, generative exploration activities were undertaken in Australia, Brazil and the USA. In all, 80,541m of drilling were completed globally with total expenditure of $31.2m over the year.
The outlook for growth capital expenditure in the Americas region over the next few years until 2024 relate mainly to the Gramalote and Quebradona projects, where Quebradona allows the group to diversify into copper production at an attractive estimated copper AISC margin of around 60% to 70%. For more information on these projects, see Greenfields projects, Colombia.
Brownfields exploration focuses on delivering value through accretive additions to the Ore Reserve at existing mines as well as new discoveries in defined areas around operations.
During 2020, brownfields exploration activities were undertaken across the globe. Brownfields exploration completed 1,409km of drilling with a total expenditure of $63.1m (capital) and $67.7m (expensed) for the year.
Our planned investment in brownfields exploration drilling ramps up to a level of approximately $150m to $160m for Ore Reserve and Mineral Resource addition in 2021.