Reclamation and Restoration
Scars on the land may last thousands of years even if mined areas stabilize and the vegetation recovers. Carefully planned reclamation can restore natural processes and greatly speed site recovery. Reclamation in the National Park System focuses on reestablishing landscapes and environments that mimic the surrounding undisturbed lands. Mine structures such as mills, shops, headframes, and others of historic value are stabilized and preserved. Otherwise, the pre-mine condition is restored wherever possible. Reshaping the surface stabilizes slopes and drainages, waste rock piles, tailings ponds, highwalls, and access roads. This reshaping often requires the use of heavy equipment to contour the land to look and function like the surrounding undisturbed lands. The restoration of stream channels also provides for the reintroduction of plants and animals that were lost because of mining. The same type of earthmovers that created the mineral extraction scars are often the best suited to remove them.
Cleanup or treatment of toxic materials prevents further impairment of the environment. Small quantities of mining related materials, such as chemicals or fuels used in mining and milling are completely removed. Large quantities of naturally occurring materials such as acid-generating waste rock may be treated on-site. Applications of lime may provide a buffer to prevent the generation of acids. In more severe cases, limestone drains or artificial wetlands filter heavy metals and reduce acidity. In worst-case scenarios, active water treatment systems may be necessary.
The goals for revegetation of mine sites in the National Park System are the restoration of native plant populations and patterns. The first consideration is the suitability of the soil for revegetation. In harsh conditions, topsoils, compost, or specific nutrients can be added. Specialized nurseries may be needed to propagate suitable plant materials. Sometimes, revegetation work is focused on establishing pioneering species to allow for natural succession. Time and nature then restore the natural productivity in the site.