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Simulating avalanches to enhance the safety of Chilean copper miners

On 8 August 1944, 102 people lost their lives in an avalanche accident that engulfed the living quarters of workers in a Central Andean copper mine. This accident serves as an example of many similar disasters that struck mining regions during the past century.

In most cases these days, the miners no longer live alongside the mine workings, but the access roads are still exposed to the danger of avalanches. When these roads have to be closed, moreover, the mine operators generally incur severe financial losses. The safety authorities would therefore like to know with certainty whether an avalanche is capable of reaching the road, the extent of the snow masses that are likely to be released and, if the road is engulfed, how quickly it can be cleared.

Zufahrtsstrasse zu der Codelco Andina Mine in den chilenischen Anden

Fig. 1: Access road to the Codelco Andina mine in the Chilean Andes. Photo: Patricio Cerda

Against this background one of the world's largest copper mines, the Codelco Andina mine in Chile, engaged the SLF to produce a forecasting tool tailored to its needs. A PhD candidate consequently developed a model which, for the first time, can calculate the run-out distances of wet snow avalanches from the prevailing snow conditions. It is based on numerous observations of mostly fairly small wet snow avalanches that have occurred in the vicinity of the mine. In order to calibrate the computer model to their practical purposes, the Chilean safety authorities must enter a variety of data, including the terrain properties and starting zones. Equally important is current information concerning the structure or bonding of the snowpack as well as its temperature and water content, not only in the starting zone, but also along the avalanche path.

Eine Nassschneelawine verhindert die Zufahrt zur Codelco Andina Mine

Fig. 2: A wet snow avalanche obstructing access to the Codelco Andina mine. Photo: Cesar Vera Valero

The SLF has already been testing the model in the Andina mine for two winters. In view of the highly promising results, the safety authorities will now be integrating the model in their everyday operations.