24 December 2020

The deadly landslide at the Carmen Copper Mine in the Philippines

Posted by Dave Petley

The deadly landslide at the Carmen Copper Mine in the Philippines

On 21 December 2020, in the aftermath of Tropical Storm Krovanh (also known as Tropical Storm Vicky), a very large landslide occurred at the Carmen Copper Mine, also known as the Toledo copper mine, at Don Andres Soriano (Lutopan), Toledo City, Cebu in the Philippines.  This landslide is known to have killed four miners, whilst six more remain missing, with no prospect of survivors.

This landslide has raised barely a ripple of interest beyond the Philippines, which is very surprising because there are two remarkable videos of the failure and its aftermath.  The first can be seen below.  The main phase of movement starts at about 2 minutes 40 seconds if you are impatient, although the first part of the video shows both the creep of the landslide towards failure and the precursory failures from the mass as the mass deforms:


Watch to the end of the video – there is a surprise in store at about 3 minutes 20 seconds.  At the very end you can see the aftermath of this secondary event.

The second video captures he same event from a different angle:-


As well as the main failure, this video shows the terrifying dynamic displacement wave that was created when the highly mobile front of the landslide impacted the lake.  It is this displacement wave that caused the fatalities.  The videos implied that the motion of the slope had been anticipated.  Perhaps the size and magnitude of the wave was a surprise?

Reports today suggest that new cracks have been observed around the edge of the mine, causing the authorities to evacuate 400 families for the area.  This has happened on the day before Christmas.

The best image that I have found of the aftermath of this landslide is this one, tweeted by News5 in the Philippines:

Carmen Copper Mine landslide

The aftermath of the Carmen Copper Mine landslide. Image tweeted by News5.


It seems to me that the main failure occurred in the upper half of the slope, with loading and entrainment causing the lower part to become involved.  This means that most the material had a large fall height, which will explain the energy when it entered the lake.  The slopes around the failure have been left in a very steep condition.

This is yet another major, fatal landslide in a large mine.  This has occurred at the same time as a major spike in iron ore prices, driven by a major fatal landslide at the Vale Córrego do Feijão mine in Brazil last week, which killed an employee.

Once again I note that the occurrence of landslides associated with large-scale mining is unacceptably high.