For the more information about the geologic resources of the National Park Service, please visit http://www.nature.nps.gov/geology/.
Abandoned Mineral Lands
Abandoned mineral lands (AML) are among the many types of disturbed lands in the National Park System. AML sites are 1) underground and surface mines, 2) placer and dredge sites, 3) oil, gas, and geothermal wells, and 4) associated facilities. Commodities mined at these sites range from "hard rock" minerals, mainly those that contain metals such as gold, silver, lead, and copper, to "soft rock" minerals such as coal, salt, and sand/gravel. Sites often have waste rock piles (unprocessed, sub-grade mined rock), tailings (mined rock that has been processed to remove the desired commodities), abandoned roads, fuel storage tanks, drainage diversions, buildings such as mills and assay shops, deteriorating structures such as headframes and tramways, and abandoned heavy equipment.
Not surprisingly, the legacy of abandoned mineral lands spans North America. Mining for flint, obsidian, and native copper for tools and weapons, turquoise for jewelry, and clay for pipes began with the arrival of prehistoric peoples. During the 16th century, expectation of mineral wealth drove Coronado's conquistadors beyond the edge of civilization to the heart of an unknown continent. Later, the lure of gold and the prospect of great wealth were responsible for Europeans settling in the western United States. With the beginning of the industrial age, the young nation, hungry for energy, exploited its mineral resources of coal, oil, gas, and uranium, and this too left its mark on the land. Deserted, these sites stand in silent testimony to those who pioneered this country in search of mineral wealth.
NPS AML Program
The NPS program includes Servicewide and Regional activities to inventory, mitigate, and restore AML sites, as well as efforts to preserve historic mining features and critical habitat.
The NPS has an active and on-going AML inventory program. To date, 23,182 AML features have been identified in 129 of the 399 units that make up the National Park System.
Hazards and Safety
Many hazards are associated with abandoned mineral sites, including open shafts, deadly gases, radioactivity, and others. Learn more...
AML sites can have detrimental effects on soils, water, plants, and animals. They can also provide habitat for wildlife including some rare or endangered species.
Mitigation and Restoration
Mitigation and reduction of AML hazards is a priority for the NPS. Additional reclamation efforts focus on reestablishing landscapes and environments to mimic the surrounding undisturbed areas and speed site recovery.
Has mining occurred in national parks?
The answer is yes. In fact, mining still occurs in some parks. Most abandoned mines inside national park boundaries are not from recent mining operations, but from operations that existed before parks were established.
Approximately 2,600 abandoned mineral sites have been identified in the National Park System, in all 7 regions of the system, and in 45 states. This number translates to approximately 23,000 individual features, including adits, shafts, surface mines, and wells. Additionally, the National Park Service estimates that 5,000 miles of abandoned access roads exist in park units that may or may not require reclamation. Abandoned mineral lands are lands that were disturbed by mineral extraction --underground mining, surface mining, dredging, and oil and gas exploration--and then abandoned at a time when miners were not required by state and federal laws and regulations to reclaim their operations. Abandoned mineral lands can be underground with numerous mine openings such as adits and shafts, or on the surface in the form of strip mines, quarries, open wells, or pits. Abandoned mineral lands are not only the actual mine or well, but include access roads and trails, historic buildings such as mills and company towns, tailings and waste rock piles, and abandoned machinery such as ore carts, steam engines, and pump jacks.
Last Updated: February 27, 2013