Huw Clarke
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How the fracking process works

13 December 2012 Last updated at 10:46 GMT

The government has given the go-ahead for a firm to resume the controversial technique known as fracking to exploit gas in Lancashire.

The company, Cuadrilla, was stopped from fracking after two tremors near Blackpool.

Huw Clarke, a geologist with Cuadrilla, explained the fracking process to the BBC's John Moylan on site in Lancashire.