Shares in Dana Petroleum and Minmet, two exploration companies with Irish links, have shed some of the substantial gains notched up in dazzling trade in London on Monday. Dana's shares had soared by 34 per cent to 13.75p sterling on reports that it was in talks over a major North Sea acquisition. But the shares fell back yesterday by 0.5p to 13.25p with 9.5 million shares changing hands. Minmet's shares had soared by 20 per cent to 15.25p after a television performance by the company's chairman, Mr Jeremy Metcalfe. Mimmet shares yesterday eased 2.5p to 12.75p.