Kensington Mine – Stage III TTF Dam Raise

In 2018 we performed a Dam raise in remote South East Alaska at the Kensington Gold Mine for Coeur. The Dam was designed to have a life expectancy of 200 years, and implemented a concrete spillway with a structural fill of roller compacted concrete (RCC) underneath it. With very limited space, a batch plant was setup for producing the structural concrete spillway and the RCC. AAP reused the mine waste rock to crush and produce the specified gradations required for the structural concrete, RCC, and different zone fills. This design also utilized a dual diversion pipeline, consisting of two 26” HDPE pipes diverting runoff from an adjacent lake to the stream behind the tailings lake. The Dam face itself consisted of 2 different zone fills that had to be placed simultaneously and covered with a Geosynthetic Clay Liner and a HDPE Liner.