Chile’s Minister of Mining Marcela Hernando said during the agency’s investigation into a sinkhole that has formed at Lundin Mining’s Chilean unit Ojos del Salado that the event was caused by “overexploitation” and excessive mining at the site.
Work is continuing to determine the origin of cracks close to the subsidence and any potential impact to an aquifer near the operation, which first discovered the 36.5-meter-wide sinkhole early this month.
Hernando said the probe, which is being carried out by the National Service of Geology and Mining, ratifies the initial information – that there is an overexploitation by Ojos del Salado.
“The Gaby 4 house was designed and authorized for an exploitation of 400,000 tons and, according to the data obtained in the investigation, it was detected that 300,000 t have been extracted and within the house there are at least 300,000 t more, which clearly means that there is an overexploitation that would be related to the subsidence and that in turn could have affected the existing aquifer in the place,” said the secretary of state.
The office added that there are three areas of concern, specifically cracks in the surface that it has been monitoring since the first days of the incident.
“Sernageomin [National Service of Geology and Mining] detected these cracks and has been monitoring them with radar system, drones and extensometers, instruments that so far have not shown that these cracks have increased their dimensions. It is important to emphasize that we have information, delivered by the company, that in that sector where the cracks are there would be no excavation or mining activity, unlike the sinkhole that is related to mining. In addition, from tomorrow Friday work will begin on geophysical studies to confirm this information and deliver this information to the authorities and the community for their peace of mind,” officials confirmed.
To its end, Lundin Mining said it is also continuing to monitor and perform technical analysis to identify the factors that led to the sinkhole’s formation, an event which it first confirmed 30 July. It is also continuing to work in cooperation with the Sernageomin to collect and analyze geophysical, geotechnical and hydrogeological data.
“For this purpose, the company has mobilized resources such as sophisticated technology and experts to guide this investigative process,” it said.
“The company is providing regular updates to community members, union representatives and other stakeholders, and has expressed its full willingness to collaborate with investigative proceedings initiated by the national environmental regulator, Superintendencia del Medio Ambiente (SMA), the Atacama Local Prosecutor’s Office (PDI) and an inter-ministerial working table to be formed, as announced by the Minister of Mining.”
Operations at Alcaparrosa remain suspended. The status of the sinkhole has not changed materially since detection.
Lundin Mining officials also said, per local news outlets, that Ojos del Salado was informed of the government’s conclusions and it would “analyze” them, “see responsibilities, and take the pertinent measures.”
Sources: lundinmining.com and ‘Overexploitation’ by Canada’s Lundin caused massive sinkhole near mine: Chile (yahoo.com)