Warning over depths for ‘fracking’

CONTROVERSIAL “fracking” for shale gas should only take place at least 600 metres down from aquifers used for water supplies, scientists have warned.

A new study revealed the process, which uses high-pressure liquid pumped deep underground to split shale rock and release gas, caused fractures running upwards and downwards through the ground of up to 588 metres from their source.

The research, published in the journal Marine and Petroleum Geology, found the chance of a fracture extending more than 600 metres upwards was exceptionally low, and the probability of fractures of more than 350 metres was 1 per cent.

Researchers said the study showed it was “incredibly unlikely” that fracking at depths of 2km to 3km below the surface would lead to the contamination of shallow aquifers which lie above the gas resources.