Before hoisting persons and to assure that the hoisting compartments are clear of obstructions, empty hoist conveyances shall be operated at least one round trip after—

1. (a) Any hoist or shaft repairs or related equipment repairs that might restrict or obstruct conveyance clearance;
2. (b) Any oversize or overweight material or equipment trips that might restrict or obstruct conveyance clearance;
3. (c) Blasting in or near the shaft that might restrict or obstruct conveyance clearance; or
4. (d) Remaining idle for one shift or longer.