Chuquicamata Slurry Transport, Calama, Northern Chile

Codelco

2014 - 2015

Situation

Chuquicamata copper mine is located in the north of Chile, 15 km north of Calama and 230 km northeast of Antofagasta.

As part of the upgrade of the existing conventional Tailings Storage Facility (TSF) at Talabre to a Central Thickened Discharge (CTD) Scheme, we were engaged to undertake a basic engineering design of the High Compression (HC) / High Density (HD) thickener underflow transport to the TSF.

The thickened tailings scheme comprises 12 thickeners. The thickener underflow is pumped to the Talabre TSF from a pump station located at the thickener platform via 4 pipelines installed on two earthfill ramps (2 pipes on each ramp). The tailings are discharged from the end of the two ramps using a distribution system to form two separate central thickened tailings stacks (cones).

The pump station receives tailings from the following three sources and has to accommodate tonnage ranges between 23.4 ktpd to 426.8 ktpd:

  • Chuquicamata –CH (under Operation).
  • Ministro Hales-MH (under Commissioning).
  • Radomiro Tomic –RT (at Design Phase).

Each tonnage scenario required analyses for 3 different solids contents, namely 64.5%, 67% and 68.5%.

The scope of work for the project included, design of the pump station and pipelines for transport of highly viscous thickened tailings at 68% solids (fully sheared yield stress up to 110 Pa) with a total flow rate of between 2,600 to 17,000 m3/hr, pipeline access ramps and extension, distribution system at the stack, thickened tailings beach modelling and development over time.

Solution

The designed thickened tailings transport system for Talabre includes the following main components:

  • Above ground steel (polyurethane lined) pipeline for transport of HC thickener underflow to the TSF.
  • Total length of the each pipeline of approximately 3.1km (uphill).
  • Investigation of a range of slurry solids concentrations (62% to 68% (by weight)).
  • Pipeline diameter (4 parallel pipelines) of DN 550mm.
  • Design flowrate (for each pipeline) of 2,600 to 17,000m3/hr.
  • Total maximum static head of 60m.
  • Total maximum head of 300m.
  • Pump station comprising 5 trains of pumps (4 operating +1 standby).
  • Number of pumps per train = 6 (24/20 500HTP).
  • Total number of installed pumps = 30.

One of the key operational challenges we addressed during the design phase was the operation of the pump station and pipeline to cater for the wide range of flow rate fluctuation.

Outcome

The basic engineering design for the thickened tailings transport and distribution system has been successfully completed for a 35 year operational life (i.e. end of 2022 to end of 2057) based on the tailings production schedule provided by CODELCO.

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For further information please contact:

Charles Vuillier on 0435087562 or via email at charlesv@atcwilliams.com.au