Hydraulic design of a thickened tailings gravity discharge and distribution system

Abstract

It has become common practice for mining tailings to be thickened before being deposited in a tailings storage facility (TSF) to increase water reclamation, reduce overall footprint and comply with current environmental regulations. TSFs that impound thickened tailings (TT) typically consist of distribution systems along the TSF embankments or in the basin's perimeter, defined by a deposition plan. These main deposition systems include linear distribution discharges or manifolds, a pressurised radial distributor or a distribution box with a series of spigots discharging over the TSF.Other deposition options may be considered for conditions where the site's topographic surface is relatively flat or the basin is somehow constrained to allow for perimeter filling. For example, TT can be deposited within a TSF basin with a flat topography using spigots located on elevated discharge platforms that are relocated throughout the TSF's life span.TT can either be discharged onto the TSF surface from the top or the bottom of these discharge platforms. The discharge platform is susceptible to abrasion when TT is discharged from the top of the platform. Alternatively, a hydraulic design challenge is introduced when TT is discharged from the bottom of the platform with the aid of gravity as the rising tailings could block the exit as deposition progresses.This paper provides a methodology that has been applied in large tailings projects with gravity distribution and discharge systems, and a design guide for its application in the industry.