Moomba was currently supplying 120 terajoules (113 million cubic feet) of gas a day and Santos was targeting production to rise to about 150 terajoules within the next 24 hours, the company said in a statement e-mailed to Bloomberg News. The plant, which is 59.75 percent owned by Santos, was previously producing about 400 terajoules a day of gas. The closure of the plant cut off gas supplies to cities including Sydney and Adelaide. The supply cut forced OneSteel Ltd., Australia's second-largest steelmaker, to shut most of its biggest manufacturing plant's operations at Whyalla, South Australia state. Australian Gas Light Co., which buys gas from Moomba for its customers in New South Wales, said it can't guarantee full supplies next week. An initial investigation of the incident pointed toward the failure of a heat exchanger inlet nozzle as the source of a gas release that led to the fire, Santos' Managing Director John Ellice- Flint said in the statement. Ellice-Flint said a review of the fire will continue in the next seven to 10 days after which the company would be able to provide a more accurate forecast for the restoration of full supply. Santos shares on Friday fell 2.6 percent to a two-week low of A$6.69 in Sydney. Shares in Origin Energy Ltd., which owns 13.2 percent of the Moomba plant, fell 1.9 percent to A$4.66 P.I.N//Bloomberg