27 November 2015
The Hpakant jade mine landslide in Burma
Media reports suggest that the rescue and recovery operations in the aftermath of the Hpakant jade mine landslide have now ceased, with 114 bodies recovered. The number of unrecovered victims is unclear, but is likely to to be in the order of a further 90 or so. Reporting on the incident remains somewhat mixed – for example many sources suggest that the landslide was 200 feet (about 60 m) high, whereas the images clearly show that it was very much larger than this, such as this one (via Reuters):
Meanwhile, a war of words has broken out regarding who was to blame for the Hpakant jade mine landslide. A key statement has come from the Nobel laureate and political leader Aung San Suu Kyi (often known as Daw Suu), who reportedly stated:
“As far as we understand, it was the fifth similar incident this year. This sort of accident is common just because there is no rule of law. It also reflects lack of due consideration for the safety of people’s life and property.”
On the other hand, the Director general of the Department of Mines, U Win Htein, appears to disagree. The Myanmar Times reports:
“U Win Htein, director general of the Department of Mines under the Ministry of Mines, said there is no need to upgrade safety rules as companies involved were not breaking the law. He added that mining firms comply with all the rules and regulations, reporting monthly to the ministry on safety procedures and the impact of their activities.”
I cannot comment on the legal situation in Burma, so have no idea as to whether the mines at Hpakant were operating within the law. However, it must be a moral responsibility of any mining company to ensure that its waste tips are stable and safe. This is entirely achievable, and indeed is the norm in most of the world. Of course the legal framework should ensure that this is the case, but even without a set of laws the norm must be to ensure that the mines are safe. Attempts to blame the victims, which seems often to be the case when this sort of event occurs on the basis that they should not have been living there, are not reasonable in my view. The Myanmar Times reports:
“U Win Htein said while the ministry is providing aid, it cannot do much more, as victims of the landslide were in the area illegally. The ministry sets out specific areas for mining companies to dump their waste – people should not enter these areas to look for jade,” he said. “But some people from remote areas had built huts to stay there. The soil collapsed due to rain. It’s a tragic case and I am very unhappy that people were killed.”
The proximity of dwellings to the mining operations in the Hpakant area is disturbing. This is a Google Earth image of a small part of the Hpakant area:
26 November 2015
A debris flow of ice, water and sand?
Just when you think you have seen it all, this pops up on Youtube:-
This event was apparently associated with the very heavy rainfall across the Middle East at the end of October and first half of December, as described by NASA. This debris flow appears to have been the result of a very heavy hailstorm, but I know no more. A still from the video,suggests that there is a large concentration of hailstones in it:
I have never heard of such a debris flow, but am no expert on processes in deserts. I don’t even know if it is for real, though it does not look fake on first inspection. Does anyone know more?
Hat tip to Phil Ashworth on Twitter for coming across this one.
24 November 2015
The Burma jade mine landslide disaster
News from within Burma about the jade mine landslide disaster is hard to find, so inevitably I have to rely on external reports. The Chinese news agency Xinhua reports that to date 113 bodies have been recovered, and there is a lack of clarity about how many more people may have died. The landslide struck an informal settlement, so little information is available. However, the Myanmar Times suggests that it is likely to be in the order of 200 people,
The best image I have seen of the landslide is this one, from Eleven Media Group / AP:
The image appears to show a classic mining flowslide, originating from a spoil heap. Note the figures in the lower part of the landslide in a small track, which give an idea of the scale of the Burma jade mine landslide. The slide itself has in interesting structure, with very strong levee structures on both sides. Note also a small number of houses on the right side of the landslide – this may give an indication as to the location of the settlement before the landslide. There can be essentially no prospect of survivors.
Landslides of this type should be entirely avoidable – the potential for the failure of spoil tips has been known for half a decade, and in countries with good mine management the occurrence is now very low. That there are these repeated mining landslides in the jade mine area of Kachin State indicates poor mining practices.
Youtube has some mobile phone footage of the attempts to recover the victims:-
Whilst mining practices by illegal miners are undoubtedly very dangerous, this landslide is unlikely to have been triggered by such small scale activity. The other spoil tips on the photograph above have similar geometries to the one that failed. These need urgent attention.
23 November 2015
A rather splendid rock and ice avalanche video from New Zealand
Ryan Taylor was on a ski mountaineering trip in Mount Cook National Park when he captured a quite splendid rock and ice avalanche that originated from the Hochstetter Ice Fall below Mt Cook itself:-
In the commentary that he posted on Youtube he wrote the following:
Glacier collapsing in Mt Cook National Park, New Zealand caught by photographer Ryan Taylor during a ski mountaineering trip. I also captured a series of ice the size of several buildings falling off the Hochstetter Ice Fall below Mt Cook (highest peak in NZ). Similar events are naturally occurring several times a day (at 13 seconds in the video you can see a similar, smaller collapse in the background of the video) but it is evident climate change is causing glaciers to recede at an unprecedented rate. New Zealand’s 1st ski area was once located on the Ball glacier below Mt Cook which is now covered in rock debris. I assume with increasing average temperatures we are seeing more melting and consequently an increasing ratio of rainfall to snowfall in the accumulation areas of glaciers. It is important to raise awareness around climate change at this time with the international conference on climate change in Paris coming up. For those who don’t care about the glaciers disappearing it has potential to effect economies through loss of tourism and means less water available for irrigation.
The transition of this collapse event into a rock and ice avalanche is very interesting, as is the motion of the mass on the low angles slopes below. Of course this is quite a low friction system, with ice rich debris moving across a frozen surface, so mobility of the landslide mass is comparatively high.
22 November 2015
Vasquez Canyon landslide
A significant landslide has developed in the last few days in Vasquez Canyon, in Santa Clarita in California. The landslide, which appears to be progressive and has no obvious recent trigger, has caused extensive buckling of the road, which has been closed over a three kilometre stretch. This image, from the Santa Clarita Valley Signal, provides quite a good general view of the situation beyond the road:
The landslide has caused impressive damage to the highway:
interestingly, the media are suggesting that this buckling has occurred because the road is moving upwards. Whilst this might sound a little odd, this excellent drone footage suggests that this might the case:
This is a still from the drone footage of the landslides, showing the damage to the highway:
This is Google Earth imagery of this section of the road, dated April 2015 – i.e. seven months ago:
There are clearly some signs of instability in this image, and note the other landslides in the image. The section of road that has failed is in a box cut, so it would appear that unloading of the slope may be a key factor in the landslide. And interestingly, this imagery from two years ago (May 2013) suggests significant movement at that time as well:
And finally, this is Google Street View imagery of the road, taken in 2011:
The extensive deformation in the road was clear even then – indeed the road shows longitudinal cracks along this entire section. Thus, although this landslide looks very sudden, it has been developing over a prolonged period.
19 November 2015
The nearest piece of land is the island of Lefkada. On the west coast of the island is a famously beautiful beach at Egremni:
The landslides that affected Egremni Beach were captured on a video by a fisherman who was located on a boat just off the coast:-
The aftermath is a series of large landslides that have left very large volumes of debris on the beach. This oblique aerial shot, from The Pappas Post, shows the largest of the landslides (note the smaller ones at the top of the image too):
And this image, also from The Papas Post, shows the landslide from a more traditional near-vertical perspective:
If this earthquake had occurred on a summer day then there would have been a large number of fatalities on the beach at Lefkada, so in a sense this was very lucky escape. However, it is also likely that the debris from these landslides will take a long time to clear, such that Egremni Beach has been changed in perpetuity.
According to the Washington Post, there were two fatalities in the earthquake. One of these, a 69 year old woman, was killed by a rockfall that struck her house.
17 November 2015
High resolution imagery of the Bento Rodrigues dam failures
Thanks to the many people who have been providing comments on my posts about the Bento Rodrigues dam failures (see posts here, here, here and here). We have been frustrated by the lack of high resolution images, either satellite or aerial photograph, of the failure site. However, overnight Caner Zanbak tracked down a site with SPOT 6/7 imagery of the site, provided by Airbus Defence and Space. For the first time we can see properly what happened. This is an overview of the Bento Rodrigues dam failures:-
For comparison this is the Google Earth image of the same location, taken in 2013:
This is a zoomed in image of the failed tailings pond and the Fundao Dam site:
This is Google Earth imagery of the same site from 2013. I have annotated the image:
The Fundao Dam, which I have marked A, has filed completely. Indeed there is hardly a trace remaining of the original structure. But note also the near-total removal of the levees marked B, C and D on the image above. This begs the question as to the collapse sequence – did for example, collapse of levee B trigger the failure of Fundao Dam? My sense is that it remains most likely that the Fundao Dam itself failed first, and that the loss of support from the other levees then triggered their subsequent collapse. I cannot see how a collapse of levee B would have triggered collapse of levee C for example, unless this caused a loss of support. However, others will know more about such things than me, and I would welcome comments and observations.
Downstream the debris reached and then overwhelmed the Santarem dam. This SPOT 6/7 image shows the site:
This is the 2013 Google Earth image in comparison, with the dam annotated with letter E:
Whilst the Santarem dam was undoubtedly overwhelmed and severely damaged, much of the structure appears to be intact – indeed the original spillway is still visible. This structure is now retaining a large volume of tailings, so ensuring that it remains intact must be a priority.
At the moment this event looks like a catastrophic, near-complete failure of the Fundao Dam, followed by failures of the other levees in the tailings ponds. A key question remains as to what caused and triggered this catastrophic failure,
16 November 2015
The Lidong Village landslide in China
Whilst for understandable reasons it barely registered on the international media radar, China suffered a major landslide on Friday night. The Lidong Village landslide, in Yaxi Township in Lishui, Zhejiang Province in East China occurred at about 10:50 pm on 13th November. At the time of writing 25 bodies have been recovered, with a further 12 missing.
ecns.cn has the best photograph of this very large landslide:
Based on this image the Lidong Village landslide appears to be a large rock and soil slide, mostly formed from deeply weathered rock (I cannot see any unweathered rock in the scar). The slide looks to be quite complex with a number of shear surfaces. Of particular interest is the grid work in the upper part of the main debris accumulation. This is almost certainly slope protection, perhaps soil nails or rock bolts, suggesting that the slope was known to have stability issues The lack of large numbers of trees on the slope suggests to me that the slope had been cleared. However, it is unlikely that the slope protection that us visible was designed to stabilise a failure as large and deep as evidently occurred.
Note also that in the bottom left corner of the image the highway has a rock shelter to protect against instability on a cut slope.
The image below, also from ecns,cn, shows rescuers working through the accumulation of debris. Note that the slope protection is visible in the top corner of the image:
Xinhua reports that the area was suffering very heavy rainfall at the time of the landslide. As yet there seems to be little online that asks questions as to why this landslide occurred. It is not obvious to me that the road should have disrupted the tow of the landslide, which was on a slope on the other side of a small river. I would be very interested to see an image of this site before the Lidong Village landslide occurred, but as yet have not been able to identify a location.
12 November 2015
Samarco dam failure
On Youtube there is a video that provides a compilation of videos that are purportedly from the Samarco dam failure that released a mudslide of tailings that destroyed the town of Bento Rodriguez in Brazil a week ago. The video is over 12 minutes long and has clearly been obtained from elsewhere:
The first sequence shows water cascading through the spillway of a dam. I do not believe that this is anything to do with the Samarco dam failure – it does not seem to fit with the observations of the accident.
The second sequence, starting at about 24 seconds, clearly does show an aspect of the disaster. It is not great quality, but my interpretation is that it shows the area of the Fundao dam shortly after its failure. This appears to be be tailings left in the tailing pond:
Whilst this image appears to be site of the dam itself, or what was left of it. There appears to be a great deal of dust in the air – the remains of the movement perhaps?
This actually seems to be the best footage available so far of the site of the Samarco dam, the Fundao dam, that failed, though it does not shed much more light on the disaster.
The next sequence, starting at about 50 seconds, is the most intriguing. This seems to show a very large mudslide arriving in a small rural community in good weather. The slide is enormous and extremely destructive:
I am unsure as to whether this is the event at Bento Rodrigues caused by the Samarco dam failure, but its fits the known facts. It is certainly a most impressive landslide.
Most of the remainder of the video shows the damage from the landslide, which has been described elsewhere.
Meanwhile the fallout continues. As Samarco and its owners struggle to manage the disaster and the publicity, and of course the likely costs, there are suggestions in the media that there had been warnings two years ago that the Samarco dam was not safe:-
A 2013 report conducted by The Instituto Pristino linked to the Federal University of Minas Gerais, warned of structural design flaws and predicted the circumstances that could lead to a dam burst at the Samarco operation.
“The report had already highlighted the fragility of these structures and the necessity of increased rigor in monitoring them,” Brazilian state prosecutor Carlos Eduardo Ferreira Pinto said.
This report is available online in Portuguese as a pdf. The report seems to indicate the potential for the Fundao dam to be destabilised by proposed works for Samarco. It is unclear as to whether the recommendations were taken up or whether the effects noted here played a role in the accident.
10 November 2015
The Fundao Dam
It is increasingly clear that the disaster at the Samarco mine that destroyed the town of Bento Rodriguez in Brazil in a mudslide of tailings last week was caused by the failure of one of the upstream structures, the Fundao Dam. Unfortunately as yet I have struggled to track down a decent image of the site of the dam failure. The best I have managed is this YouTube video of the site, which was pointed out in a comment by Caner Zanbak, shot from a helicopter:
It is really hard to understand exactly what this imagery shows because the camera never stands back from the site of the former dam. But the images do seem to show near complete destruction of the Fundao Dam itself, and extensive loss of tailings from the pond that it retained. Fortunately the retaining structures to the adjacent ponds appear to be intact. This is approximately the site of the former dam:-
Google Earth has a good sequence of images of the dam site over the last decade. This is the most image of the Fundao Dam, dated August 2013. The video above suggests that considerable work had been undertaken in this area since this image was collected:
Back in August 2005 this area was completely undeveloped:
By May 2008 the development of this site was underway. Although partially obscured by cloud the dam was apparently under construction:-
By February 2011 the dam was fully formed, although less high than at present, and a large volume of tailings was stored behind it:-
None of these images give any hint as to why the Fundao Dam failed so dramatically. There is no obvious sign of instability in the dam itself, nor in the adjacent slopes, as far as I can see. The most recent image does show an increase in the amount of water flowing from beneath the dam, but this is probably not a factor. The dam does not seem to be located on an unstable piece of terrain, although Google Earth is not up to assessing this properly. It is all very mysterious, and we can only hope that the investigation is open and transparent so that lessons can be learnt.
Of interest perhaps this brief report on the website of Reta Engenharia:
But note that the diagram does not seem to show any works on the Fundao Dam itself, and there is nothing that I have seen that indicates that the failure was linked to this project.