26 December 2020

The Carmen Copper Mine landslide in the Philippines – the slope evolution before failure

Posted by Dave Petley

The Carmen Copper Mine landslide in the Philippines – the slope evolution before failure

It is now clear that the ongoing post-landslide operation at the site of the Carmen Copper Mine landslide in the Philippines has transitioned from a rescue to a recovery operation.  The loss of the workers feels both tragic and unnecessary; questions need to be asked as to how such a tragedy can occur in a large, apparently well-managed mine.

Meanwhile, I have been looking at the archive of Planet Labs images of the site.  This is not an easy place in which to obtain satellite imagery due to the amount of moisture in the atmosphere, but I have found two good PlanetScope images that are quite revealing.

This image of the site of the Carmen Copper Mine landslide was collected on 14 October 2020:-

Carmen Copper Mine landslide

A Planet Labs PlanetScope image of the site of the Carmen Copper Mine in the Philippines, collected on 14 October 2020. Image copyright Planet Labs, used with permission.

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Whilst this image of the site of the Carmen Copper Mine landslide was collected on 17 December 2020, a few days before the failure:

Carmen Copper Mine landslide

A Planet Labs PlanetScope image of the site of the Carmen Copper Mine landslide in the Philippines, collected on 17 December 2020. Image copyright Planet Labs, used with permission.

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The slope that failed last week is at the north end of the mine.  I have created a slider that will allow a comparison of the two images, although I am not able to embed this in WordPress.

The image from October shows a slope that retained the mining benches in at least a part, and at this resolution (about 3 m per pixel) there are few obvious signs of instability.  However, by December the slope had evolved dramatically.  The benches had disappeared, there are signs of a scarp forming on the west side of the slope, there is a large amount of scree in the botton part of the slope and the upper portion appears to be deformed.

Thus, on the face of it I would suggest that the slope had deformed considerably, which makes the tragedy even harder to understand.

I would very much like to see some InSAR data for the site of the Carmen Copper Mine landslide over the last six months.

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Reference and acknowledgement

Planet Team (2020). Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https://www.planet.com/