A written determination on such application shall be
rendered within 15 calendar days following receipt of a complete application
and statement with all required supporting documents; provided, however, that
such period may be extended by mutual agreement. The determination shall state
whether such proposed action may or will not have a significant effect on
the environment. The board and/or its staff may hold informal meetings with
the applicant and may meet with and consult any other person for the purpose
of aiding it in making a determination on the application.