Privately held, Houston-based Northstar Interests Inc. plans to acquire substantially all of the Gulf of Mexico properties of Petrohawk Energy Corp., Houston, (Nasdaq: HAWK) for $52.5 million in cash. The properties have proved reserves of approximately 26 billion cubic feet of gas equivalent (70% gas; 59% proved developed; 27% operated) and current production of approximately 10 million cubic feet of gas equivalent. The transaction is expected to close in March. Petrie Parkman & Co. was advisor to Petrohawk.