30 CFR § 56.19072
Skips and cages in same compartment.
When combinations of cages and skips are used in the same compartment, the
cages shall be enclosed to protect personnel from flying material and the
hoist speed reduced to man-speed as defined in standard 56.19061
, but not to exceed 1,000 feet per minute. Muck shall not be
hoisted with personnel during shift changes.