AMINEX plc, an Irish oil and gas explorer saw the sharpest rise in its share price in four years in London yesterday, after tests at the Sunny Ernst-2 well in Texas “materially exceeded expectations”, the company said.

AMINEX, the Irish oil and gas explorer with operations in Africa, rose to a two-month high in London trading after saying the value of its US reserves was about two- thirds higher than previously thought.

Aminex, the oil and gas company listed on the London and Irish Stock Exchanges, today announced its preliminary results for the year ended December 31 2007 revealing a net loss in profits for the period.