Unless the context clearly requires otherwise, as used in this chapter, the following terms have the following meanings:

(1) “Adit”, any practically horizontal way in or to a mineral deposit to be used for the same purposes as a shaft;

(2) “Coal mine”, any strip mine or underground excavation from which coal or lignite is extracted for commercial purposes and including the mining plant and all parts of the property of such mine, on the surface or underground;

(3) “Director”, the director of the division of mine inspection of the state of Missouri;

(4) “Mine inspectors”, those persons employed by the division of mine inspection, including the director, who are charged with the inspection of coal and noncoal mines in this state;

(5) “Mineral”, any metalliferous element or ore, coal or lignite, or any nonmetalliferous element or ore, except barite, marble, limestone, and sand and gravel;

(6) “Noncoal mine”, any open pit or underground excavation from which minerals, as defined in this section, except coal are extracted for commercial purposes, including the mining plant and all parts of the property of such mine, on the surface or underground;

(7) “Operator”, the person, firm, or body corporate who or which is the immediate proprietor, as owner or lessee, of the mine and, as such, responsible for the condition and management thereof;

(8) “Shaft”, any vertical or near-vertical opening through the strata which is to be used for ventilation or escapement, or for the hoisting and lowering of men, ore or material in connection with the mining of minerals;

(9) “Slope”, any inclined shaft or way in or to a mineral deposit to be used for the same purposes as a shaft;

(10) “Strip mine”, any excavation in which the superincumbent strata are removed, exposing the mineral so that it may be extracted and loaded by hand or mechanical equipment in open working;

(11) “Working place”, any room, face, crosscut, or pillar where a mineral is being mined or extracted and where one or more miners per working shift of the mine are regularly employed until the place is stopped.