16 April 2013

Is the Bingham Canyon copper mine landslide the most expensive single mass movement in history?

Posted by Dave Petley

Further news is emerging about the landslide at Bingham Canyon copper mine last week.  The transparency of all involved is impressive to behold, and is a remarkable contrast to the much more costly in human terms landslide at the Jiama mine in Tibet.  I thoroughly recommend that you visit the Kennecott Utah Copper flickr site, which has some wonderful images of the landslide.  I cannot post them here, but do take a look.

In landslide terms this event was a major success, with one substantial caveat, in that detailed monitoring allowed the event to be predicted, which meant that the mining operations were stopped and the mine was evacuated prior to the event.  The mine was using slope deformation radar systems provided by the Italian Company IDS, which can detect movement in the walls of the mine.  Interpretation of the movement patterns can be used to forecast and even predict a failure event – indeed this is an area that our research group at Durham has worked upon in some depth.  The caveat of course is that the size and travel distance of the landslide does not seem to have been anticipated.  Indeed Rio Tinto released a market report that said:

The size of the slide was significant,” the company said in an emailed statement. “We don’t have information yet regarding the magnitude or impact. We do know that the flow into the pit extended beyond the scenarios we forecasted, having a greater impact on equipment.

I suspect that we need to undertake more research on the ways that we can extract this sort of information from these datasets – my colleagues and I have also been working on this.  It would be fascinating to back analyse the dataset from this event to see if we can develop better techniques.  I suspect that if we transfer the techniques we have been developing in New Zealand and Italy to this setting and data type we might be able do this better.

Meanwhile, the implications of this event are becoming apparent.  Locally the mine is continuing to produce copper through stockpiled resources (they are reported to have 20 days worth of resources), but the Wall Street Journal is reporting that the mine is asking its workers to take leave.  As the images below show, the landslide has caused the loss of a large part of the wall of the pit, filled the mine floor, destroyed buildings and the haul road, and buried equipment.  Mining cannot be restarted until the haul road is rebuilt (in itself this is not trivial), and the above article suggests that it will take months rather than weeks to restart production.  A key issue will be the stability of the material left on the slipped slope – if further movement occurs then restarting mining will be difficult until it has been stabilised.



The costs of the landslide are interesting.  The mine produces 17% of copper in the US and 1% worldwide.  One estimate has suggested that the landslide might cost Rio Tinto $1 billion, which would I think make it the most expensive landslide of all time.   The Wall Street Journal has an estimate that is hard to read:

Commonwealth Bank said Monday that assuming the Bingham Canyon mine isn’t operational for the rest of the year, the mine likely would report a loss of US$79 million. The bank had previously expected the mine to earn US$701 million this year, about 6% of Rio Tinto’s total earnings.

My interpretation of this is a loss of $770 million, slightly lower but still a huge sum of money. There are also some concerns that the event might cause an increase in global copper prices, but so far this does not seem to have occurred.

I am sure that more information will emerge in the next few days – I will post again if this is the case.