The operator shall effectively close or fence all openings to mines abandoned after June 3, 1941, so that persons or animals cannot inadvertently enter therein.
Abandoned vertical shafts and other abandoned openings leading to underground workings, which shafts and other openings are abandoned after August 26, 1949, shall be closed within ninety days after abandonment as follows:
(A) Vertical shafts shall be completely filled with earth or other noncombustible material, or the top of such shaft shall be covered with a substantial reinforced concrete slab, the design of which has been approved by the chief of the division of mineral resources management.
(B) Other openings not potentially usable in later mining operations shall be closed with earth or masonry in a way that may reasonably be expected to prevent unauthorized persons from entering the same.
No operator of a mine shall refuse or neglect to comply with this section.