B. The winning and working on land held or occupied with land used for the purposes of agriculture of any minerals reasonably necessary for agricultural purposes within the agricultural unit of which it forms part.
B.1 Development is not permitted by Class B if any excavation would be made within 25 metres of the metalled portion of a trunk or classified road.
B.2 Development is permitted by Class B subject to the condition that no mineral extracted during the course of the operation shall be moved to any place outside the land from which it was extracted, except to land which is held or occupied with that land and is used for the purposes of agriculture.
B.3 For the purposes of Class B the expression “the purposes of agriculture” includes fertilising land used for the purposes of agriculture, and the maintenance, improvement or alteration of any buildings, structures or works occupied or used for such purposes on land so used.