From the High Country News weblog The Range (Heather Hansen):
[A] possible solution, currently being field-tested by a non-profit based in Carbondale, may change the reclamation landscape entirely. Since 2007, the Flux Farm Foundation has been working on reclamation with a promising substance known as biochar. Biochar is made by burning biomass (like wood, animal and crop waste) in an oxygen-limited environment, resulting in a stable form of carbon that has superior water- and nutrient-retention abilities.
These characteristics make it an ideal candidate to restore moonscape-like mine sites, where vegetation (that could capture toxic metals leaching out of abandoned mines and into waterways) is long gone.
Using biochar to reduce metal toxicity and to boost the fertility of compromised soil isn’t a new concept, but using it clean up mines is. The Mountain Studies Institute, based in Silverton, has done some small-scale biochar trials on mine lands in the San Juan Mountains, but Flux Farm’s Hope Mine Project is the first time an entire mine has been taken on.