Diversion of water from a tailings dam : Spillway arrangement and spillway channel designed to be maintenance free for 1000 years

Abstract: An elaboration on how to construct a spillway for closure for a large tailings pond completely enclosed by embankments, leading to a situation where construction in bedrock is not possible is presented with the following conclusion. A stepped spillway arrangement constructed with granite blocks will require of large blocks for being stable, and will require of filters that are not always considered functional in long-term perspective. It is presented an analysis of the overall stability of the structure proposed and of the stability of its individual blocks.  In addition, it will be impossible to design a vegetated channel that remains stable, without silting and without erosion, over thousand years without maintenance.