14Estimated average annual volume or mass of project natural gas

14  Estimated average annual volume or mass of project natural gas  (1) The participants in a relevant operation must give to the Commissioner estimates of:  (a) the operating life of the operation, in years; and  (i) if the participants will measure by volume—the total volume of project natural gas to be recovered during the life of the operation; or  (ii) if the participants will measure by mass—the total mass of project natural gas to be recovered during the life of the operation.  (2) The estimates must be given to the Commissioner in the financial year before the production year.  (3) As soon as practicable after receiving an estimate (including a revised estimate under subsection (4)) from the participants, the Commissioner must notify the participants in writing that the Commissioner:  (a) accepts the estimate or revised estimate; or  (b) has substituted an estimate under subsection (5).  (4) If, from new information, it appears that an estimate notified by the Commissioner is inaccurate, the participants must give to the Commissioner a revised estimate.  (5) If, having regard to relevant information, the Commissioner is not satisfied that an estimate given by the participants for the purposes of subsection (1) or (4) is reasonable, the Commissioner may substitute an estimate that the Commissioner is satisfied is reasonable.  (6) For an operation in which natural gas will be measured by volume, the estimated average annual volume of project natural gas is (using the estimates notified by the Commissioner):   (7) For an operation in which natural gas will be measured by mass, the estimated average annual mass of project natural gas is (using the estimates notified by the Commissioner):   (8) The estimated operating life of the relevant operation is the period of years estimated as the operating life, as notified by the Commissioner, beginning with the production year.