The acidic, metal-laden runoff that can be produced from disturbed rock at mine sites may be more preventable than previously thought.

Aquatic ecosystems near mine sites can be harmed by acid and metalliferous drainage (AMD), a process in which sulfide minerals brought to the surface react with water and oxygen to produce sulfuric acid. The resulting acidic wastewater can dissolve toxic metals from the surrounding rock, harming downstream habitats.

Previous studies using the common sulfide mineral pyrite had shown that adding silicate can help to suppress AMD formation. However, this treatment was effective only in pH-neutral conditions.

Now, a team that included researchers from Flinders University in South Australia has shown that the silicate treatment is effective even in acidic conditions when a mixture of sulfide minerals is present. This suggests that silicate AMD suppression can be realized in a broader range of mine sites than previously thought.