Chuquicamata full-scale field deposition trial

Abstract

A large-scale field deposition trial was carried out at the Chuquicamata mine's Talabre Tailings Storage Facility (TSF) in Chile to study the achievable beach slope with the current tailings in the absence of further thickening. The tailings received at the Talabre TSF are a mix of tailings from two different operating mines; Chuquicamata (CH) and Ministro Hales (MH). The field deposition trial was run with a total discharge flowrate of 100 L/s from two outlets each discharging 50 L/s. The average as-received solids content of the slurry during the field trail was 52% ranging from 56.5-40.8% (solids by weight). The trial was run for 56 days from early August to early October 2014 with continuous tailings discharge for eight hours per day. The limitation on discharge time was to prevent rapid initial build-up and possible mass slumping which would interfere with the interpretation of the results. Nevertheless the scale of the trial was such that 'continuous' discharge conditions established quickly at the beginning of each deposition day, and the trial is considered to be representative of continuous discharge conditions. As expected, discharge of tailings resulted in the formation of a plunge pool at the impact area of the slurry stream at the head of the beach then self-formed channels that developed on the beach as the slurry left the plunge pool. The tailings beach that forms by this mechanism is similar to a full-size stack. This is a clear distinction from smaller scale deposition trials that are often reported which involve the deposition at very low flow rates or of discrete batches of tailings which result in a beach formed by layers of sheet flow. The preliminary results and findings from the monitoring and observations of this trial deposition including the achieved beach slope are presented and discussed in this paper.

Rheology for deposition control and deposit failure risk analysis

“…Beach slopes at some sites are presented in Simms (2017). Other recent examples are Wenberg et al (2020 ) at -3%; Pirouz et al (2015), who found a 1.5% beach slope for a large pilot trial but for a yield stress of ~10 Pa; and Ruhanen et al (2018), who found a high beach slope for a pilot paste plant (~6%). Similar sites show depression of the beach slope as the scale of the deposit decreases (for example, Addis & Cunningham (2010)).…”