LONDON (Dow Jones)--Rockhopper Exploration PLC (RKH.LN), a North Falkland Basin oil and gas exploration company, said Friday that the Ernest 26/6-1 exploration well was spudded on July 23, and said the well is being drilled to an estimated target depth of 2,400 meters. MAIN FACTS: -Rockhopper will drill Ernest as operator with a 100% interest. -Drilling operations are expected to take 30 days and a further announcement will be made once drilling is completed. -Ernest is being drilled using the fourth rig slot in the overall drilling program of the Ocean Guardian rig. -On completion of the Ernest 26/6-1 exploration well, it is currently anticipated that the Ocean Guardian will return to Rockhopper's Sea Lion 14/10-2 Well to conduct flow testing on the oil discovery. -Shares at 0830 GMT up 6.50 pence, or 2%, at GBP331 pence, valuing the company at GBP637.26 million. -By Razak Musah Baba, Dow Jones Newswires; 44-20-7842-9275; [email protected] (END) Dow Jones Newswires July 23, 2010 04:35 ET (08:35 GMT)