BHP Billiton Ltd plc has decided to spend USD 300 million development of the Mad Dog field in the Gulf of Mexico. Final investment approval this month would pave the way for first oil production by the end of 2004. The production facility will have a capacity of roughly 80,000 barrels a day and 40 million cubic feet of gas a day. BHP Billiton holds a 23.9% interest in the eight block Mad Dog unit with BP plc holding 60.5% and Unocal Corp 15.6%. Results of the Mad Dog 4 appraisal well indicated a hydrocarbon reserve size estimated at 200 million to 450 million barrels of oil equivalent.