Borders & Southern Petroleum Plc, a U.K. explorer operating in the Falkland Islands, soared in London trading after saying its Darwin field may yield about 190 million barrels of gas condensate.
Shares rose 59 percent, the most since it first sold shares in May 2005, to close at 32.5 pence. Samples from the reservoir indicated volumes of between 130 million and 250 million barrels of condensate, a light crude oil produced in association with gas, it said in a statement.
Borders & Southern rose as high as 131 pence earlier this year on optimism about its Darwin and Stebbing prospects off the South Atlantic islands that Margaret Thatcher went to war to keep British in 1982. The company said last month that Stebbing is unlikely to be commercial.
Based on the Darwin test results, Borders will now start a new drilling program with both exploration and appraisal wells, though the drilling is unlikely to start before 2014, it said today. The company is exploring options for funding, including bringing in partners, it said.