Underground Chuquicamata is a strategic mining project for Codelco, the state owned Chilean copper mining company. 140,000 tons of ore will be mined and treated per day, making Chuquicamata one of the largest mining operations on the globe with an estimated investment of more than US$ 4.2 billion by 2019. The total underground development contemplates no less than 100 kilometers of tunnel development until 2019 by when the project should reach design capacity.
The Chuquicamata underground expansion will be implemented, using conventional drill and blast drifting. Due to the nature of the orebody, the geological conditions and the strength requirements for the underground support, demanding fortification systems for the infrastructure below the caving ore body apply. Fiber reinforced shotcrete and a dense pattern of yielding bolts are used throughout the extraction drives, drifts, ramps and undercuts.
In addition to the development of the tunnel infrastructure, up to 900 meter deep shafts, ore passes and ventilation raises are being built. Such structures are very demanding in terms of the volume and requirements of concrete and shotcrete which makes the Chuquicamata underground project a challenge from a technical as well as a logistical point of view. Due to its remote location, more than 1,500 kilometers away from the capital of Chile in one of the driest deserts of the world, mine suppliers and contractors have to deal with a very harsh climatic environment more than 2,000 meters above sea level. Sika serves Chuquicamata from the Sika supply hub in Antofagasta with extensive storage capacity on site.
Sika is contracting a large volume of the concrete business at Chuquicamata, providing a range of products and support for wet-mix shotcrete, fibers, conventional concrete, selfcompacting concrete and products for the maintenance of the large ore treatment facility on site. For every developed meter, around 170 kilos of Sika admixtures are used. The alkali-free accelerator represents the largest off-take by volume, making up to 85% of the total demand.
Main efforts are currently guided towards the implementation of Viscocrete, Plastocrete, alkali-free accelerators technology for concrete lining and shotcrete mix-designs in combination with fibers of different types. Pre-dosed cementitious grouts for the extensive cable bolting represents another part of the business. It is also expected that Sika will be able to provide other technologies in the future to offer an integrated product mix for the underground development at Chuquicamata.
Acciona Ossa Consortium, Astaldi Construction, Aveng Grinaker, Mas Errázuriz