17 October 2017
The Bellavista heap leach gold mine landslide in 2007
Posted by Dave Petley
The Bellavista heap leach gold mine landslide in 2007
On 21st October 2007 a landslide effectively closed the Bellavista heap leach gold mine in Costa Rica. This landslide is subject to a court case that is currently being heard in the Ontario Superior Court of Justice, with a claim if about $100 million being made against SRK Consulting (US), who undertook engineering and design work, by B2Gold, based in Vancouver.
Cyanide heap leaching involves creating piles of crushed ore, mined from an open pit site in this case, which are then washed with cyanide solution. The leachate is then collected at the foot of the pile, allowing the gold to be extracted. Clearly the risks of pollution are sufficiently high that great care is needed to protect the integrity of the heap. The Bellavista site is located in heavily weathered, humid tropical mountains that are also seismically active. Slope instability is a challenge in such environments, as multiple examples on this blog have shown.
The Tierra Group has a description of the work that they undertook at the site in 2007, which includes this image of the ore heap:
The Bellavista heap leach gold mine, via the Tierra Group
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In their description of the project, the Tierra Group state that:
…our Team performed a geologic hazard assessment which ultimately identified existence of a mega-landslide (35,000,000 m3) underlying a waste rock dump and flanking a heap leach pad. A site wide Environmental Audit was prepared for the Secretaria Técnica Nacional Ambiental.
This landslide induced instability in the heap; unconfirmed reports suggest that movement was observed in 2006. The mine was reportedly closed in July 2007. In October 2007 a major landslide occurred in the southeast corner of the heap. The Ecologist has this image of the landslide, taken in January 2009:-
The aftermath of the landslide at the Bellavista heap leach gold mine. Image via The Ecologist / CEUS del Golfo via Earthworks.
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After this major landslide, the mine was closed and has subsequently been remediated. Of course I cannot comment on the liability issues that this case raises (and I cannot comment on the validity of any of the legal claims for obvious reasons), but once again problems of slope instability and mining are clear.
Dave Petley is the Vice-Chancellor of the University of Hull in the United Kingdom. His blog provides commentary and analysis of landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings.
In other words, who was the idiot who thought this was a good idea in the first place? I visited there before the mine was built, when it was being strenuously opposed by local people who said that building a mine on a slope, on top of 17 active springs, above a stream close to a sensitive estuary, was a recipe for disaster. B2Gold to my knowledge has never tried to clean up the mess, and in fact I think Costa Rican activists tried to get the government to seize the equipment that was left behind to help pay for the clean-up before the company moved everything to Nicaragua.
[I am not sure this is correct though? When I look at the latest images on Google Earth it is clear that the site has been mitigated. Who did this work if it was not the owners? D.]
B2 Gold did not build this mine, It was built by a small junior in Toronto Glencairn Resources managed by investors with very little operating expertise. In fact I think they had none! The two principals were a journalist who was with a newspaper I think. One was a former stock broker, so a recipe for disaster for sure with two people who know zero about mining running a mining company.
Hello
We are just preapering a report on recent (13.02.2024) heap leach slide occurred in İliç, Erzincan, Turkey.
Best Regards