Acid mine drainage is an unavoidable consequence of some coal mining operations. Typically runoff pH is below 3.5 and
at these pH levels heavy metals are mobilised. Leachate from coal reject dumps may require collection and treatment to
raise the pH and precipitate the metals before being discharged.
A bi-product of coal mining operations at Clarence Colliery is coarse washery reject. At present the coarse reject is
deposited above ground and rehabilitated. Adjacent to Clarence Colliery is the Kable's Transport Pty Ltd sand mining
operation. It has been proposed that co-disposal of the rejects from both operations may produce a product whose leachate
has near neutral pH.