Acid Mine Drainage

Refers to the leaching of acidic waters from previously mined metal or coal sources.

Sulfuric acid (acid rock drainage) comes from natural oxidation of sulfide minerals causing the formation.

What is it?

When sulfide minerals are brought to the surface and exposed to oxygen or meteoric waters, sulfuric acid is formed. Contaminating water sources for surrounding environment and communities.

Although this process occurs naturally mining and construction can cause it to occur at an accelerated rate

How is it formed?

1,300 miles of streams and 20,00 inactive mines are affected by acid mine drainage (general)

Lack clean drinking water and the survival of local flora and fauna

Silverton, Colorado- Mineral Creek has a pH of 3 and is laden in heavy metals.

Silverton has a history of mining for gold and silver which causes excess sulfide minerals to oxidize, creating acid runoff.

In Colorado

The sulfide mineral is oxidized when expose to air and water. 2FeS2 + 7O2 + 2H2O = 2FeSO4 + 2H2SO

The iron goes into solution and oxidizes from ferrous to ferric iron. 2Fe2+ + 1/2O2 +2H+ = 2Fe3+ + H2O

The ferric iron precipitates ferric hydroxide. Fe3+ + 3H2O = Fe(OH)3 + 3H+

Sulfuric acid is created (Acid) FeS2(s) + 15/4 O2 + 7/2 H2O = 4H+ +2SO4

-

+Fe(OH)3(s)

Steps of Acid Mine Drainage

Acid Mine Drainage

As ferrous iron precipitates as ferric hydroxide and is combined with fresh water, a yellow-orange solid known as yellow boy is formed.

Other types of iron precipitates may occur and contribute to the discoloration and toxicity of the water source.

Discoloration

The angle of repose of a mine waste pile is about 45°

Waste piles of this angle are prone to excessive erosion, preventing the accumulation of biomass

In order for mine waste to be reclaimed, the overall biomass must be increased.

Angle

Angle/Waste Pile

Shown to improve water retention, stabilize heavy metals, and raise the pH of contaminated soils.

Biochar is a sustainable material that is created through the carbonization of lodge pole pine which ahs been decimated by the mountain pine beetle of Colorado.

Simulates the effects of pyroysis, or thermochemical decomposition, on soil productivity (Fire)

Biochar helps amend soil and promote soil revegatation

Biochar

Biochar

Cooking stoves which produce biochar as a by-product

Industrial models capable of producing biochar

Bio-oils Replacing fuel oil.

Fuel gasses Reacts in a similar manner like coal.

Biochar & Alternative Energy

Reduces nitrogen oxide (green house gases) one of many causes of global warming.

Increases pH, stabilized heavy metals, and improves water retention of soil

Can be used as a bio-fuel

Why use biochar?

http://www.biochar-international.org/biochar/faqs#q5

http://www.biochar-international.org/biocharhttp://kerrcenter.com/publications/intern-repo

rts/biochar_factsheet.pdfhttp://www.biocharproducts.com/bio-oil.htmlhttp://www.diacarbon.com/bio-fuel

Bibliography