‘THERE COMES A time in every rightly constructed boy’s life’, said Mark Twain, ‘when he has a raging desire to go somewhere and dig for hidden treasure.’ But it’s not just boys who succumb. Grown-ups do too. As a seven-year- old, Max Anderson turned his parents’ garden in suburban Derby into a muddy honeycomb of shallow holes. Twenty years later the digging impulse returned with a vengeance. So he quit his job on the travel pages of the Sunday Times and lit out for the gold- fields of Western Australia.