Prior to approving an application for an excavation permit or an application for an annual excavation inspection, the Planning Board shall hold a public hearing within 30 days of receipt of a completed application. A notice of said hearing in compliance of the provisions of RSA Chapter 155-E, as shall be, from time to time amended, shall be sent to all abutters, shall be published in a paper of general circulation in the Town, and shall be posted in the Town. Within 20 days of said hearing or any continuation thereof, the Planning Board shall render a decision approving or disapproving the application, giving reasons for disapproval.