Innovative Remediation and Passive Water Treatment at a Legacy Arsenic-Tin Mine and Processing Site

Ashton Soltys from Earth Systems joined us and shared the details of a case study of the first stage of remediation at a legacy underground arsenic-tin mine in Eastern Australia. Prior to remediation, the site hosted several waste rock dumps and tailings storage facilities – generating conventional Acid and Metalliferous Drainage (AMD); as well as residual soluble processing wastes which produce arsenic rich effluent. Stage one works included excavation of reactive mine wastes (waste rock and tailings), limestone blending, and strategic placement into an engineered containment cell to lower acidity loads leaving the site. In addition, an innovative Permeable Reactive Barrier (PRB) was installed as a temporary measure to immobilise soluble arsenic. Design aspects and philosophy will be discussed, as well as water quality data pre and post stage one remediation works.