"We looked at autonomous operations of equipment as being the same type of technology that could be used on the moon as well as in a mining application, " said Michele Blubaugh, manager of Intelligence Technology Services at Caterpillar.

WSJ: Exhausting the Earth's Resources? Not So Fast

The Department of Minerals and Energy has said it will issue new prospecting licences within six months of application, and mining ones within one year, and the pace has accelerated in recent months.

ECONOMIST: Mining in South Africa

If the current application is accepted and viable coal is found a further application would need to be submitted before any mining could start.

BBC: Landslip fear at Ystalyfera over coal exploration plan