The design and construction of a dual function tailings facility

A facility was required to accommodate a fly ash tailings as well as a waste water stream. The topography of the site enabled the construction of a dam split by a central watershed, a conventional tailings deposit on the one side, and to the other an impoundment facility constructed to water retaining standards for the water stream. The sizing of the two dams was such that the siltation rate of the water dam corresponded to the rate of rise of the tailings facility. After two years of operations, the dam would be completely silted up, this would then provide a base for the adjacent tailings facility to extend onto. The design of the water compartment required innovative details in terms of the underdrains and decant infrastructure required for its long term role as a tailings facility, whilst still ensuring that it met its initial function of a water retaining dam.