Mt. Polley Mine Breach Result of Design Fault
Likely, B.C. – . The independent expert panel tasked with finding the cause of the breach of the Mount Polley tailings pond near Likely last August, has released its report.
The panel has found that it was a fault in design of the foundation that led to the breach, saying the design failed to take into account the sub-glacial geological properties of the area. The report says the wall of the dam was too steep, the load in the dam too much for the underlying foundation to support.
The Panel said increased inspections of the dam would not have prevented the breach as the breach occurred without warning.
The panel has recommended a new tailings regime be adopted involving Best Available Technology and pointed to an Alaskan example where tailings are de-watered before deposited, creating a dome like structure, that allows water to run off, rather than collect.
Comments
Well then who ever designed it, who ever approved the design and built it should all be in jail.
The Panel said increased inspections of the dam would not have prevented the breach as the breach occurred without warning.
What a crock of BS. Maybe if they would have had more inspections they would have seen the water creeping through the wall before it blew out.
Considering when the dam was built that most likely wasn’t a consideration at the time and may of not been known so commenting on that they should of been thrown in jail is a bit pre-emptive don’t you think Pval without knowing if they knew of such a thing at the time of the dam building
Funny in the pic at the time of the dam breach there was equipment at the breach site or was that just a coincidence.
Shortly after the breech happened there was one engineering firm that was trying to distance themselves from Imperial Metals, I wonder if they had a hand in initial design?
Another thing I find stange is that I thought the npp elected a new leader, he has been out of sight so long hard to remember his name or what he looks like. He could not get up to area fast enough when the accident happened and get anything that even remotely looked like a microphone under his nose….till some brought to his attention that an ndp government issued the permit to allow construction of tailings pond. Suddenly POOF he disappeard into thin air and has not been seen since. Someone better call the cops.
Just like the rest of his union party. Work to be done,but nowhere to be found. Are you surprised??
The original designe was most likely ok for a certain water level in the early stages of the mine but it is my understanding they kept building the wall higher to hold the tailings and water which caused the pressures to be too great and finally the wall blew out. Obviously the height of the wall should not have been allowed to be raised without proper support.
oldman1, heard that story as well. Which is likely true, They just made the dykes higher thinking that this would hold more water, failing to realize the height of the berm has a design ratio to the width of the berm. Thus it would need to be an engineered soil from the base up, Likely if they needed to raise it 5 feet, they likely needed the base to be 15 ft wider, not just rolling dirt down the bank either. Engineered and compacted with stepped work.
The question about the design. Did the engineer follow all the design requirements of the day. Was a proper geotechnical report been done. Did the owners of the mine interfere with the process of building a proper pond. Was the dam built in accordance to design, if not why was it signed off. Did the owners make any changes to the dam, and notify the engineer of record? There is too many questions out there that needs to be answered before an engineer can be held accountable. The likely reason for the failure will likely be alterations were made without notification to engineer of record, and or did not heed to his recommendation, due to cost issues.
However, I like the Alaskan method. That would make sense, but it will cost the mines more money to operate the water system…. however the water can be reused.
If you read the actual report it states that the dam was properly approved and that the glacial and preglacial deposits were not detected at the time the dam was approved not because of an oversight but due to the building techniques of the time.
The report also does not lay fault with the inspectors as there was no indication of a potential dam failure and the water behind the dam was not to blame for the failure but places most of the blame on The undetected glacial deposits beneath the dam.
However that won’t stop the detractors from laying blame somewhere because they don’t want to believe the findings of the report
Dearth some people just can’t handle facts.
The people with the torches and pitchforks are disappointed with your post, Dearth.
Reminds me of the damn built in California, was built on a fault line undetectable at the time, when it gave away killed many people.
I am surprised that they didn’t use new technology once it was available to audit this pond. As this has happened before the excuse of at the time it was undetectable holds no water.. The environment shoukd always be protected first, ahead of money. This water run off they mentioned is not just water, it’s a mix of toxins.. They say it like its drinking water.. Just shows how honest they are being .
So PVAL who is being dishonest?
Read the last paragraph of the story… De water, water run off.. Sounds so pristine doesn’t it.. Better than saying.. The toxic waste water will flow dropping off sediment but carrying toxins to where ever routed.
Just watched the news about this.. Part of the reason for the failure was the continual building up of the walls at the wrong grade..
Toxins have been found to be very low as stated by the mine manager at the very beginning. Nothing to see here, move on.
The mine had actually applied to raise the dam and in doing so flatten the slope. Before this work could be done the dam failed because of being built
on glacial sill. Inspections would not have detected this. This was all stated in the report.
Toxins very low, yeah sounds like a politician seamut.. It won’t kill you now, but down the road who knows, as the mine owners we are willing to risk your lives for profit. Nithing to see here.
No the height of the pond WAS raised already and it contributed to the failure. Just stating facts ;)
I am sure the technology is out there with X-ray etc to see this problem now. It should be used to make sure all tailing ponds are safe.. If not build another to the new specs, just don’t keep building it up till failure.
I am going to say BS on glacial sill foundation. If the foundation was no good why did it not blow a hole in the foundation and leave the wall standing?
Was Worksafe BC in charge of this report?
You guys really should read the report before commenting.
Studies have shown toxins very low and some no higher than the background chemical levels.
Those that performed the testing did not think the glacial till was a problem.
The dam was pushed over because of the till weakness and the study also said water pressure was no problem for the dam other than at the weak location.
Some not so bright commentator on the Jill Krop how wondered why dams where built out of dirt, hilarious. Wonder what she would think of the Bennett dam or the that the majority of 1504 registered dams in BC are built out of dirt.
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