(b) Workers at the face shall be protected as follows:

1. (1) On top of the bank, by fencing with guard rails or ropes, by using railed platform, or by using safety belts and life lines. This does not apply where the bank is less than 20 feet high, or the slope below is less than 50 degrees from the horizontal, or where no work is performed within 10 feet of the edge.

2. (2) On the face, by removing loose rock from over the working place, and by the use of safety belts and life lines, portable staging, boatswain chair, or skips especially designed for use at pit faces. If a boatswain chair is used, the employee shall be attached thereto with a safety belt and life line.

   When necessary for safety, two or more persons shall be employed in cooperation with each other in drilling, blasting or removing loose rock.

3. (3) At the foot of the bank by removing loose rock from above the working place, and maintaining a ready way of exit to a place of safety.
4. (4) By any other means affording safety equivalent to that provided by (1), (2), and (3) of this subsection.