Mont. Code Ann. § 82-2-224

Any party seeking to condemn property for open-pit mining purposes pursuant to Title 70, chapter 30, shall serve written notice on all owners and purchasers under contracts for deed of property within 300 yards of the surface tract sought to be condemned or shall file a plat showing the boundaries of the property sought to be condemned in the office of the county clerk and recorder. The filing of the plat constitutes notice to the owner or owners not personally served with written notice.