Digging Deeper Becoming More Attractive, Financially Possible

Developing a new shaft is regarded as a grudge purchase by mining compa-nies and their shareholders because of the capital-intensive nature of such projects.

- Victor Moolman

Developing a new shaft is regarded as a grudge purchase by mining compa-nies and their shareholders because of the capital-intensive nature of such projects. However, 2017 Rapid Underground Mine & Civil Access Conference organising chairperson Murray Macnab avers that underground orebodies are coming into their own once again.

“Older underground mines that were originally designed for a 25-year life are now being considered for extension to beyond 50 years; new subvertical shafts and tertiary shafts are also being considered, where the orebody economics allow for it, as potential new investment opportunities.”

The approval of a new shaft construction is determined by whether the size and depth of the orebody supports financially viable mining operations, says Macnab.

He points out that the economics of orebodies and the ability to raise capital determine whether a shaft can be deepened, upgraded, revamped or a new shaft can be justified. The economics are linked to the commodity price, but, with the recent and steady improvement in commodity prices following the 2016 price slump, business cases are improving.

Macnab tells Mining Weekly that, with the advent of aerial magnetic surveying technology years ago, the “easy pickings” mines have largely been discovered and exploited through opencast mining, but some of these operations are ageing and must either be expanded as underground mines or be replaced.