Now I know many of you live in or near cities and have never had the experience of being near one of these monsters, especially when it is running.
When I was younger I worked on a construction project that use a tiny JD350 dozer. When It was running, parked near very soft groun two things occurred. First was a sight I will never forget being a sport fisherman. The vibration of the machine brought literally thousands of dew worms to the serface. The second was that the macine started to sink into the ground.
I mentioned this because I wanted you to know what these machines are capable of. And this was a small machine.
Later in life I worked in the mines and got up close and personal with some of the biggest machinery I ever worked around.
Now, if you were to stand next to something as large, or larger than a D9, there is a definate Shaking of the ground and a very loud noise from the engine.
When you build an earth dyke, two things should take place.
1. The base fill should consist of very large boulsers and;
2. There should be a membrane in place that lays on the bottom and against the dyke.
There are various reasons for this but the main ones are for stability and to prevent seepage.
After looking at still photos of the Dozer sitting very close to the breach (Ican't find any to download right now) two things appear to be evident.
1. There appears to be no membrane.
2. There appear to be no boulders.
From all this I can only conclude that the dozer had been working on the dyke (evidenced by how close to the breached it sits abandoned) and the vibration turned the mix beneath it to soup, the water seeped through weakening the dyke which inevitably burst sending millions of gallons of dirty water through the breach. Some of it made a immediate right turn and went down a small creek into Quesnel Lake. The rest went basically left pushing the slag to one end of Polley Lake.
It's going to be real interesting to see what the panel says, how long of a delay the government puts on publishing the report so they can spin its' content, and just what will happen about the cleanup.ie: who will pay for it. The cleanup I mean.
2 comments:
About the Cat. On the rear it has a Ripper which is used for ripping the ground and or moving logs and major debris of all sorts, but mostly to rip the ground to make dozing more easy during road construction etc.. I'm not sure why they would have that particular Cat with a ripper parked on the dyke, as it would be much more useful in the bush. I'm sure the mine would make better use of their equipment than to have that dozer working the dyke.
It's interesting that you mentioned a membrane, and that here, one isn't in view. There are membranes to hold back water as well as to allow water to pass while holding back certain sizes of gravels and soils. It is my guess that they wouldn't use a membrane in this instance to hold back water 100%. I would say from my experience that they did indeed want water to pass through the dyke gravels and eventually into the drainage system. They would allow this to happen because it takes approximately 100 meters of fine gravels or sands and soil for water to cleanse itself of most deposits in the tailings.
If you have ever seen the Tar Sands, you will notice that the ponds are built close to the rivers. They do this for drainage, as they do intend for the ponds to drain themselves on a steady basis. If they didn't allow for drainage the ponds would be massive and overflowing and out of control. The same drainage system would be applied here at the Polley site. This might shock people but there is probably no intention to hold back the water in the pond. Of course the kinds of gravels and sands and soils are applied to allow a somewhat measured flow of the water into the rivers and creeks.
I'm going to stick my neck out a bit here and suggest that this spill was no accident. If you look closely, the breach was above the river, and not at the same level or lower. I would say this breach was calculated and intentional as there would be little effort to calculate the soils retention,because they are almost in perfect and evenly distributed in size and quality. One can imagine without much effort to find out why they wanted the breach to happen and the monies saved.
I don't know the extent of your experience Whistlejocket, either in the bush or mining. But most "cats" I have seen on a claim have a ripper. Theyre pretty good for roads and just getting rid of house sized boulders without using dynamite. I also am not sue which photo you are referring to. The one at the top is a example of a D-9. The photo at the bottom is the actual Dozer and the dyke. Personally I can't make out a ripper for sure. It's in the shadow.
The end of the dyke shown is where the Hazletyne creek is. There is no way that a membrane would not be used to prevent poisons in the tailings to enter a fish bearing creek that empties into a major waterway.
As for your comment on the TAR SANDS, don't get me going. The seepage into those waterways is killing everything in its path. Including people downstream. The sands are a travesty.
As far as your comment on the breach being intentional, I basically don't disagree with you. But if yo also look at some of the aerial photos when the breach happened the excess slag took an immediate right turn and went down the creek.
As I have said before there are going to be lots of delays finding out just what happened. What I am sure of is that the present government is going to cover up and whitewash this in volumes we have never seen before.
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