Mo. Rev. Stat. § 293.530: Notice of opening and abandonment of mines — abandoned mines to be sealed.

1. No person is permitted to open up new mines or mining property, unless he has reported his intention to the director, together with such other pertinent information as the director may require.

2. The operator shall notify the director of the permanent abandonment of any of his mines, or of the resumption of work after abandonment or a change in the name of the mine or its owner, within ten days after such abandonment, resumption, or change of name or owner.

3. Upon abandonment of any underground mine, the operator of that mine shall seal or fence the surface openings of the mine in such a manner as to afford permanent protection to all persons and animals.