312 IAC 29-2-124
312 IAC 29-2-124 "Top plug" defined
Cite as Ind. Admin. Code tit. 312, r. 29-2-124
Sec. 124. "Top plug" means a plug or series of plugs placed between the deeper of fifty (50) feet below the lowermost commercially minable coal resource, or the lowest underground source of drinking water, and extending to the surface.