Friday, August 15, 2014

Mount Polley Disaster

 An aerial view of the Mount Polley mine tailings pond shows the area where the earthen wall gave way early on the morning of Aug. 4. A letter posted on the website of Knight Piésold Consulting said the Vancouver company had warned mine owners in 2011 that the containment pond was "getting large."
The real measure of a properly failed  tailings pond is that you have a mud slide and nothing else.   This exactly what happened here.  At the same time, i see mention of an alternative system that produces stacked tailings and gets rid of the actual pond which obviously must fail eventually creating a mess and plenty of those dry tailings.

This really makes sense as no one can provide a financial guarantee that is perpetual.
Dry stacking or better yet, pit filling at the end of mine life gets rid of the problem.  None of this ends the chronic problem provided by waste rock which still retains sulphides which is attacked swiftly enough to produce a long term acid drainage issue.
Again back filling the  retired mine pit may work well enough to limit the effects enough.
What the Mount Polley Disaster Means for Mining Companies: Steve Todoruk

Sprott's Thoughts

Monday, August 11, 2014
Henry Bonner

The mining industry can’t give guarantees just as airlines can’t.

Over the years we have seen several airplane crashes due to mechanical error that have resulted in many unfortunate deaths and injuries.

Prior to those accidents all of those passengers and all of their extended families knew that once those people boarded those planes that there was a slight chance of an air disaster but because flight travel is considered
a necessity, all concerned accepted the chance they were taking.

Similar to the exhaustive engineering that goes into building airplanes to make them as safe as humanly possible, a great deal of engineering goes into designing mines to make them as safe as possible to prevent accidents that may harm people and the environment.

The mining engineering that goes into designing mines is supposed to make them as resistant as possible to accidents that may cost lives or destroy wildlife. But things don’t always go as planned.

Just days ago, a Canadian mining company, Imperial Metals Corp. (III-T), announced that their tailings pond wall had been breached in one area at their Mount Polley copper-gold mine in central British Columbia,

In less than 24 hours after the breach, horrific damage had been caused by the tailings (leftover rock that was mined that had very little copper or gold) and water that burst into a nearby river. Fortunately the water has been continuously treated during the life of the mining operation and so is not acidic. As such, it should not be hazardous to people’s health. As it has been routinely analyzed for various metals content.

This event is somewhat analogous to a antural mudslide. Afterwards, the debris is cleaned up and people somehow get back on with their lives. In those mudslides debris has been moved sometimes settling into nearby streams, rivers and lakes. “The material released from a tailings dam is similar in composition to the material in a natural mudslide. The results of both are disastrous in the short term, but are non-toxic and recover naturally in the long term.”

By all accounts, as the media has thoroughly repeated, this type of an accident should not have happened. But we all know it doesn’t work that way. The fact is that accidents, while rare, are always going to happen. All we can do is try to learn from the mistakes and improve safety for future projects.

At this early stage after the accident, it appears the tailings pond was getting too full and that the company was in the process of having some of the extra treated water discharged, but that approval had not
yet come. This would be a touchy application and no doubt the local native aboriginals and various environmental groups would have wanted to have significant input into that decision, creating a delay which may have also partially contributed to this disaster.

Much effort will likely be put into vacuuming up the easiest-to-get tailings pond material, then pumping it back into the repaired tailings pond. The remainder of the spilt material in the nearby river and the downstream lake will likely be allowed to remain. Science has shown that the best place to put mine tailings is under water, though this typically creates a knee-jerk negative reaction from most people.

If the mine tailings material has been treated as it should have been, there should be very little copper left in the spilt material and the only other mineral that might be of concern is prrite, an iron sulphide. The good news is that in this particular type of copper deposit, there is usually very little pyrite.

Nearby residents are seeing disruptions to their water supply, but that problem will be resolved. This area of British Columbia has abundant water supplies, and I am confident that somewhere down the road the people with homes and cabins on the lakeshore now affected will be able to once again use that nearby lake water
if governmental regulatory agencies deem it safe for consumption.

Back in 1998, another mining company, Boliden Limited, experienced a similar disaster at their Los Frailes copper mine in Spain. Just like at Imperial Metal’s mine, the tailings dam breached, creating a massive
spill out of their tailings pond of around the same scale. It took several years and cost nearly $300 million to clean up.

But will Mt Polley mine close? Probably not.

This mine provided a lot of very high paying jobs, providing an excellent tax base to the local and provincial governments to support schools, hockey arenas (a ‘must’ in Canada) and curling clubs. The logging industry in this area was decimated by the pine beetle kill, so these mining jobs and tax revenues are dearly needed.

While the company works to clean up the disaster area, the engineers will be going to work to figure out what went wrong in order to prevent this from happening again.

It’s likely that accidents like this will happen again. Despite the risk, the mining industry will continue, because people need metals like copper in order to enjoy access to electricity for their homes and offices, to computers, cars, air conditioners, and other modern comforts. Even without disasters like Imperial Metals, it is already getting harder and harder to find new deposits of copper and other metals to feed development, as most of the near to surface and easy to get at deposits have been found and mined.

We are already seeing the expected outcry that mining companies shouldn’t be allowed to mine near where people live, or near wildlife or fish habitats, unless they can guarantee that this kind of accident will never happen again. But you have to recognize that we need to balance the risk of damage to the environment against the risk of a shortage of materials needed to sustain modern civilization.

I pray another mine disaster like this one never occurs again but I am also confident that we will learn and improve from the mistakes at Mount Polley. For instance, a fairly new technique called dry stacking of tailings material might be the best way to prevent these sorts of disasters in the future. There is no doubt that the unfortunate event that just occurred at the Mount Polley Mine will affect – and likely delay, other companies such as Pretium Resources Corp. and KGHM International that are currently nearing submission of their mine building permits in British Columbia.

Steve Todoruk worked as a field geologist for major and junior mining exploration companies after he graduated with a B. Sc. in Geology from the University of British Columbia, in 1985. Steve joined Sprott Global Resource Investments Ltd. in 2003 as a Senior Investment Executive.

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