LONDON (Dow Jones)--Rockhopper Exploration Plc (RKH.LN), a North Falkland Basin oil and gas exploration company, announced Wednesday it re-assigned operation of the Ocean Guardian drilling rig on Jul. 21. MAIN FACTS: -The Ocean Guardian is currently being moved to the company's Ernest prospect located on license PL024 in the North Falkland Basin where, after arrival and mobilization, it will drill the Ernest 26/6-1 Exploration Well (100% Rockhopper). -Drilling operations on Ernest are expected to take 30 days. -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 (100% Rockhopper) to conduct tests on the oil discovery. -Shares at 1347 GMT up 1.75 pence, or 0.56%, at 315.25 pence. -By Zechariah Hemans, Dow Jones Newswires; 44-20-7842-9411; [email protected] (END) Dow Jones Newswires July 21, 2010 09:50 ET (13:50 GMT)