Section R. 324.422 - Sealing of cellars and rat and mouse holesRule 422.
(1) A permittee of a well shall seal and set into the earth rat and mouse hole casings and cellars in a manner to prevent the migration of the drilling fluid and other foreign fluids into the groundwater.(2) Immediately after drilling completion, a permittee of a well shall fill rat and mouse holes on all rotary-drilled wells solidly from bottom to top with cement or other suitable material approved by the supervisor.Mich. Admin. Code R. 324.422