Samatosum - A Tale of Two Early Acid Drainage Prevention Approaches

摘要

Two acid drainage (AD) mitigation measures incorporated into the design of the Samatosum Mine Project have displayed diverse outcomes: the water covered tailings impoundment was very successful; the layered waste rock dump was not successful. The effectiveness of the AD mitigation measures has been monitored since they were implemented. Discharge from the waste dump became acid briefly during the 1995 freshet. Since 1995, the primary seep from the waste dump has become acid during every freshet, and a small seep is acid almost all of the time. A water collection and treatment system was commissioned before the 1997 freshet, and has been in operation since that time. An on-site sludge management program has been implemented to manage the residuals from the treatment process. Potentially acid generating (PAG) tailings were deposited in an impoundment designed to maintain a water cover over the tailings. There have been no indications of AD from the tailings facility to date. Water management and treatment facilities, and their post closure operation, are described in this paper. Monitoring results are also presented and discussed.