Polley mine disaster not affect Pebble
Critics are again bringing up the Mount Polley mine disaster, because the company that built the Mount Polley mine, is the one building the Pebble mine.
I researched this four years ago when the Mount Polley mine disaster occurred, and environmentalists crowed that Northern Dynasty was having the same engineering company build the Pebble mine and therefore it was sure to fail. I checked out this newest article in case it had some new information.
It's dated: August 27, 2018, and so it is very new. The very first thing I noticed, staring me in the face, was the symbol of a polar bear and the letters NRDC, , the organization that is being investigated by congress, because they are controlled by the Chinese government and are a pure propaganda machine for the Chinese. The Chinese don't want having to compete with the future low cost Pebble mine, and will do every thing to prevent the Pebble mine from being built. That includes giving out misleading articles that make the Pebble mine sound like it would be a danger to the community.
Even so, there was the possibility that they had something new to add, but when I read it, it was just a rehash of what was written four years ago. It talks about the Mount Polley mine in which an earthen dam that held back toxic waste water, failed and the toxic waste water contaminated the surrounding area. Then the article states that, since the engineering company that made that mine, is also building the Pebble mine, the same thing will happen with the Pebble mine.
Anybody that reads it might say, oh my gosh, they are right. What the readers won't realize is that it is a pure piece of miss direction, fabricated by the act of omission: deliberately leaving out important information that would invalidate what they are saying.
Here is what happened.
The earthen dam that was containing the mines' toxic waste was supposed to be built with a gradual slope so that, as it grew taller, its base would increase in thickness, and it could withstand the increasing pressure of the rising water levels. But during the construction, the builder ran short of rock fill, the material used in the construction of the dam. In response to having less building material, the construction company made the slope of the dam steeper, more like an up and down wall. This would make the dam wall thinner, which meant that they could continue building the dam higher, with the small amount of building rock that they had. Of course, this also made the dam weaker. This concerned the regulators.
The company said that the standard they were working on, that said that the dam was to be built with a shallow slope, only applied to the finished dam, not to the dam while it was in construction, because the water levels would be less than the higher final dam level. The regulators accepted the “creative” word play on the part of the engineers, because they thought that enough other safety factors were present that would preclude any mishaps.
They were also told that it would only be temporary until more material was acquired. But even after supplies were restored, the construction company continued building at the steeper level.
The second problem was that the dam was built over a layer of glacial lacustrine soil (glacial silt), 25 feet under the ground. Glacial silt is a sediment of tiny grains of sand deposited by retreating glaciers. It is less stable than other layers such as rock or compact soil, and, when subjected to increasing pressure, it changes from a solid, to a fluid. This is what happened when it was subjected to the increasing weight and pressure from the toxic waste and water that was being added behind the earthen dam. Not only did the growing lake of toxic waste water put increasing weight and pressure on the layer of glacial silt, the increasingly tall dam, also exerted downward pressure. Once this layer of glacial silt liquefied, it weakened the support for the dam, and the thin weak dam cracked and broke.
The investigation committee concluded that if the dam had been built to the specification requiring a shallow slope, it would have been thicker and would have held even when the silt layer gave way. Or if the thinner dam had been built over a sound foundation, it would have held.
Why was the dam built over the glacial soil? Because Imperial Metals, that owned the gold and copper Mount Polley mine, only did a haphazard survey of the area and completely missed the layer of glacial silt.
What does this have to do with the Pebble mine?
The way to prevent future mine failures is through the use of independent peer review groups that evaluate an engineering company's plans and critique them. It would be this group's recommendations that the regulators would follow. Plus a mining company would not be able to change anything without the changes being reviewed by experts and regulators before it would be allowed.
In that way, it would not matter which engineering company was building the mine. They would design the mine, but before the plan was approved, a group who's expertise was specifically in mine safety, would look at the plan, order any design improvements or changes, and the regulators would follow their recommendations.
Northern Dynasty has Knight Pisold Consulting (KPL) overseeing the design and construction of the mine. In addition, KPL is going to have a group of independent specialists review their plans. All work will be subjected to peer review and the checking of calculations will be documented to enable independent auditing.
It was Northern Dynasty Minerals (NDM) that insisted on an independent review panel. The peer review will allow a group of experts, that are not associated with Northern Dynasty Minerals, to evaluate the designs of the mine, and this will provide additional confidence in the validity of the plans to potential partners, the Alaska regulatory agencies, and, just as importantly, the Alaskan public.
NDM states that the selection of suitable specialists is fundamental to completing the reviews in an uncompromising manner. They must be objective as well as technically competent, and will consist of prominent and well regarded specialists, which have recognized credentials.
They will be jointly selected by NDM and Mr. Charles Cobb of the Alaska Dam Safety Program. They will provide periodic and on going reviews for several years, while the mine is being designed and built.
While it is true, that the company that is building their mine, is the one that built the failed Mount Polley mine, their plans are evaluated before they are approved.
Northern Dynasty was aware that the engineering company they were using, was the engineering company involved in the Mount Polley mine failure. But the engineering company is well versed in all the intricacy's of building giant mines, and their expertise will ensure that nothing is missed, especially since their plans are being peer reviewed.
Northern Dynasty has stressed that it will take every precaution in building their mine. They are consulting with ALL government agencies and regulator boards in order to ensure that the mine is built to the strictest safety measures.
For example:
In order to test the stability of the soils and bedrock, as well as water movement, of the area under which Pebble's tailings dam will be built, multiple cores were drilled, with some up to a depth of 5,000 feet. They will make sure that, unlike the Mount Polley mine, the ground underneath the dam is stable.
Pebble mine developers will be required to show that the tailing's dam will be safe. They must provide detailed calculations of how groundwater will move and fluctuate, explain how they will monitor the water levels and show detailed analyses of soil and rock stability. They must also show that they have done a thorough job of evaluating the potential for any earthquake activity, and that they have designed the dam to withstand the most severe earthquake that could be possible in the dam area according to detailed evaluations by the mine company and responsible public agencies
Land based earthquakes occur when the bedrock on one side of an earthquake fault slips relative to the other. The Pebble Deposit is located 18 miles from the closest earth quake fault, the Lake Clark fault. According the United States Geologic Service (USGS), all geological evidence suggests that the Lake Clark fault hasn’t shown any signs of activity since the end of the Ice Age, over 11,000 years ago. Regardless of how unlikely future earthquake activity may be, Pebble designed the mine site to withstand a 7.8 magnitude earthquake at the Clark fault, which is higher than the maximum potential calculated for the Clark fault.
Critics say that there is a possibility that there may be some small unmapped earthquake faults that run under the Pebble mine site. That trumpeted warning is meaningless because the magnitude of an earthquake is related to the size of the fault, and a small fault could not produce an earthquake large enough to bother the Pebble mine.
Some critics have said that the Clark earthquake fault might be as close as 5 miles to Pebble, instead of 18 miles, and therefore, if the Clark fault had a 7.8 magnitude earthquake that close to Pebble, it would destroy Pebble. However, the Clark earthquake fault has not been active in over 11,000 years, so the possibility that it will be active now is remote.
In addition to that, The mine plan has not been finalized. New risks will be incorporated. The final project proposal will be submitted for government and public review before any construction is started. If either the government, or the public, concludes that a 7.8 magnitude earthquake could occur close to the Pebble mine, NDM will have the independent specialists' decide what needs to be done.
NDM continues to refine its plans for Pebble, and each option will include embankments designed to withstand any seismic event that could conceivably occur in the region. If the independent specialists decide that it needs to withstand a 7.8 magnitude earthquake within 5 miles of Pebble, appropriate designs will be incorporated in its designs.
Critics say that that is not possible to build a mine that could withstand a near by 7.8 magnitude earthquake, but already there are mines that have been built to withstand earthquakes even stronger than a 7.8 magnitude earthquake.
Chile is a seismically active region, and in 1960 experienced a magnitude 9.5 earthquake, the highest ever recorded by modern instruments. Because of its seismic-risk status, its mines, some of which are the largest in the world, are built to withstand the massive earthquakes of the region, and none have failed.
Neighboring Peru has some of the world’s highest embankments for large-scale operating mines. Tailings facilities at the Cerro Verde and Antamina mines will eventually reach heights of 886 feet and 820 feet, respectively. These modern tailings facilities in Peru are designed and built to withstand intense, high-magnitude earthquakes. The ultimate height of their embankments will be much greater than what is proposed for the Pebble Project.
Critics were besides themselves, screaming that the Pebble dams would be so high that they were bound to fail. Pebbles' original dam was going to be 740 feet tall. The newer, smaller version, will be 600 feet tall. Both are significantly shorter than the Peru mines. And just like the Peru mines, they will be able to withstand intense, high-magnitude earthquakes.
Northern Dynasty Minerals (NDM) intends to reach beyond Alaskan regulatory requirements in other ways. NDM will design and construct its tailings embankments to exceed the guidelines of the Alaska Dam Safety Program. An engineering assessment based on these guidelines suggests a Class II (Significant) Hazard Potential Classification is appropriate for the Pebble mine, however NDM plans to incorporate more stringent design criteria for flood and earthquake events consistent with a higher Class I classification. That means that in addition to exceeding the safety requirements for potential earthquakes, it will also build the dam to withstand the effects of a once in a hundred year thunderstorm. The dam will be built so that even that deluge of water, won't cause the dam to over flow or break.
These 'Real Facts' show that Pebble can be built in such a manner that it will not be a danger to the surrounding countryside.
ALL of this is public information that anybody can look up!
NRDC must know this information, and yet, for some reason, they failed to mention any of this in their article.
If this is the best that they, or any of the other critics can do, it's pretty sad. The scientists doing the permitting process are not going to be swayed by the environmental critics' 'False Facts'. Instead, they will base their conclusions on science principles, and everything indicates that Northern Dynasty will receive approval to build the Pebble mine.
The Pebble mine will NOT be a danger to the Alaska salmon. It will even benefit the salmon and surrounding area, because Northern Dynasty is going to remove debris from the salmon streams and rivers, making them more salmon friendly. Critics complain about the size of Pebble's proposed power plant, as if it were an affront to the people and cities that are dependent on smaller power plants. What they don't mention, is that the Pebble power plant will supply low cost electricity to the surrounding population. Critics also insist that Northern Dynasty will be hiring people from outside Alaska to build the Pebble mine, and therefore Alaskan residents won't benefit from the high paying jobs that the mine will provied. However, Northern Dynasty has made it abundantly clear that they are going to be doing their hiring from the local population.
The Pebble mine, and its associated suppliers, will provide thousands of high paying jobs, and since the mine is planned to be in operation for well over a hundred years, these jobs will be there for generations of Alaskans. ALL Alaskan residents will benefit from the Pebble mine, because a significant amount of the money that the state of Alaska receives from Northern Dynasty, will go into the state fund that pays yearly dividends to the residents of Alaska.
Northern Dynasty states:
The goal is not to build a mine at the expense of the environment or the fisheries, but rather one that will complement existing natural resources and contribute to the long-term sustainability and economic diversity of the region and state.
This is the truth of the Pebble mine!