Influence of geotechnical parameters on the stability of progressively raised tailings impoundments with waste rock inclusions

ABSTRACT: Waste rock and tailings are the two primary types of solid waste generated by mining operations. Coarse-grained waste rocks are usually disposed in waste rock piles, while fine-grained tailings are generally deposited hydraulically in surface impoundments. Waste rock can also be placed strategically within the impoundment to create waste rock inclusions (WRI) aimed at improving its geotechnical response. Such WRI can greatly increase the impoundment stability by accelerating drainage and consolidation of the tailings and by providing reinforcement against displacement and failure. In this article, new analysis results are presented to illustrate the influence of different tailings properties, loading conditions, and WRI configurations on the static stability of an impoundment raised progressively with upstream dikes. The calculations show how the WRI affects the dissipation of excess pore water pressures (PWPs) generated during sequential filling of the impoundment while increasing its stability due to the added reinforcing components.