Section 520.290 - When unitization order to become effective; supplemental hearings(1) No order of the governing board of the State Department of Geology and Mineral Industries providing for unit operations is effective until: (a) The plan for unit operations prescribed by the board under ORS 520.270 has been approved in writing by (A) those owners who, under the board's order, will be required to pay at least 75 percent of the costs of the unit operation, and (B) those persons who, at the time of the order of the board, owned of record legal title to 75 percent of royalty and overriding royalty payable with respect to oil and gas produced from the pool or part thereof over the entire unit area; and(b) The board has made a finding, either in the order providing for unit operations or in a supplemental order, that the plan for unit operations has been so approved.(2) If the plan for unit operations has not been approved pursuant to subsection (1) of this section at the time the order providing for unit operations is made, the board shall upon application and notice hold such supplemental hearings as are required to determine if and when the plan for unit operations has been approved. If the persons owning the percentage of interest in the unit area required by subsection (1) of this section do not approve the plan for unit operations within a period of six months after the date on which the order providing for unit operations is made, the order is ineffective and shall be revoked by the board unless the board, for good cause shown, extends the time for approval.