N.M. Code R. § 20.2.21.110
The owner or operator of an existing nonferrous smelter shall not permit, cause, suffer, or allow the use of any roadway or parking area within the boundaries of the smelter and associated facilities unless the roadway or parking area is paved and frequently cleaned, or other control measures approved by the Department as at least effective to reduce fugitive particulate matter emissions to the atmosphere are utilized. Where the owner or operator of an existing nonferrous smelter demonstrates to the satisfaction of the Department that certain roadways or parking areas are used infrequently, the Department may allow the use of less effective control measures such as the application of crushed stone or periodic treatment with dust suppressant chemicals or oils to such roadways or parking areas.
N.M. Code R. § 20.2.21.110