(a) more than three layers of rope where the drum has helical or spiral grooving or does not have grooving,

(b) more than four layers of rope where the drum has parallel and half pitch grooving, or

(c) less than three dead turns of the rope on the drum.

(a) grooves that properly fit the rope, unless the hoist is being used for shaft sinking or preliminary development work during shaft sinking in which case the drum may be smooth, and

(b) flanges of sufficient height to contain all the rope and strong enough to withstand any loading by the rope.

(a) coils properly across the face of the drum,

(b) winds smoothly from one layer to another, and

(c) winds without cutting into the rope layer beneath.