After the mudslides that affected the Atacama Region in March 2015, it was necessary to make the disaster visible. This was done in an effort to show the multiplicity and origins of the variables involved.
After the floods that affected the Atacama Region during the month of March this year, it is important to show that the disaster was not only the result of excess rainfall capable of eroding naturally fragile soil but also the result of latent danger that affects an environmentally stressed region due to the presence of tailings, active mining concentrates and abandoned mineral deposits.
If we consider that the tailings are the mineral particles remaining after cleaning and that mixing these with mud creates a concentrate from which liquid has been subtracted to decrease its volume, we can then understand how informal and illegal accumulation of this material in the Salado River, an accumulation that began around 1938, means that today there are more than 350 million tons of mining waste in the sector (1). These, in turn, have been dragged to Chañaral Bay, which, as a result, has historically operated as a tailings and concentrate pool for the Potrerillos Mine – Sector of La Cascada – and for the Los Amarillos Plant, in addition to the small mines installed on the Salado River’s banks (2).
(1) Descriptions based on the definitions according to the Diccionario de la Real Academia Española (2015).
(2) The description of the risk associated with mining activities has been derived, in part, from the account of Manuel Cortés A. in “El Barro de Chañaral de todas maneras tiene depositos mineros” (Anyway you look at it, the Mud of Chañaral has Mining Deposits) in Semillas de Agua (Seeds of water) <http://www.semillasdeagua.cl/el-barro-de-chanaral-de-todas-maneras-tiene-depositos-mineros/> (May 16, 2015).
From a sequence of satellite photographs, Infographic 1 gives an account of the consequences of the landslides in some of the main settlements in the region. A closer approach shows the city of Chañaral where, in the frame corresponding to 2015, the footprint left by the mud in its encounter with the sea is demonstrated in shades of gray also marked with a broken line the intermittent courses the Salado River usually makes. When comparing the result of the event with photographs of the Chañaral Bay from 1919 and c. 2010, the increase in the surface occupied by the sediments is demonstrated, where the material dragged by the mudslide becomes another element of the coastal edge landscape with all the ecological implications that this entails.
Infographic 2 gives an account of the regulated urban areas around the Salado River affected after the March event. On the one hand, how the mud overflowed the river basin is shown, also overflowing in its path the containment walls, roads and the infrastructure placed by the city of Chañaral at the end of the riverbed. This overflow area includes areas for recreation, parks and urban walks, areas of tourist equipment, areas of high- and medium-density mixed usage, a medium-density developable area, areas of urban equipment and commercial areas, as established by the current Regulatory Plan. In parallel, part of the mining infrastructure located on the riverbank is identified, showing those urban areas that, in addition to being within the area affected by the event, present a high health and environmental risk after the event. It should be noted that in the last Chañaral Regulatory Plan – from 2003 – there are no Risk Zones associated with flooding.