ELR Citation: ELR 20017
No(s). 07SC497 (Colo. Jan 12, 2009)

The Colorado Supreme Court held that the state Mined Land Reclamation Act impliedly preempts a county's ban on the use of toxic or acidic chemicals, such as cyanide, for mineral processing in vat or heap leach operations for all zoning districts in the county. The county enacted the ordinance to prohibit a certain type of mining technique customarily used in the mineral industry to extract precious metals, such as gold. The ordinance, however, is not a proper exercise of the county's land use authority because it excludes what the General Assembly has authorized under the Mined Land Reclamation Act. The General Assembly assigned to the Mined Land Reclamation Board the authority to authorize and comprehensively regulate the use of toxic or acidic chemicals in mining operations, a field identified by the legislature that the county's ban ordinance would occupy. The ordinance, therefore, is preempted.