Well this looks pretty bad...

OK … its been couple of decades since I took a fluid dynamics course, but elementary hydrostatics says the pressure would be greatest at the lowest, deepest point of the dam. Misquoted or WTF?

It is a pretty safe assumption that the ground that the tailings impoundment was built on wasn't level. It probably crossed a low point of some sort. think of it like like any of the dams on the reservoirs north of the lower mainland. The top of the dam is the same elevation, but the highest point is in the middle, where the topography is lowest. Therefor, the point where the dam is highest is actually where the base is lowest due to topography. This is also the point with the highest pressure due to the simple fluid dynamics others have explained.

Pretty realistic overview.

http://ithinkmining.com/2014/08/08/mt-polley-the-search-for-guilty-parties-a-scapegoat/

Blame the Indians I like it.

Pretty realistic overview.

http://ithinkmining.com/2014/08/08/mt-polley-the-search-for-guilty-parties-a-scapegoat/

I've met Jack before. He's a good guy, and I feel that his assessment in that blog is the closest to the truth of anything I have read so far.

Blame the Indians I like it.

Well they DID stand in the way of the discharge permits to remove water from the pond (once again,not "sludge" or fines)

Per their website, Mt Polley is a floatation Cu mill. They likely use very similar, if not the same compounds that we do to separate ore minerals from the gangue. Almost all of these are removed with the metals. Any difference b/w their water and our would then comes from the mineralogy of the rock, which according to everything I have read, is quite benign. I would drink our discharge water without question.

I have seen comments on the green color of the water discharged into the lake. That is due to the refraction of light by suspended solids, just like you see in a glacial fed lake. It isn't some green plume of chemicals, as some are suggesting.

Mount Polley mine on-site disposal in 2013:

Arsenic (and its compounds): 406 tonnes
Lead (and its compounds) 177 tonnes
Nickel (and its compounds) 326 tonnes
Vanadium (except when in an alloy): 5,047 tonnes
Zinc (and its compounds): 2,169 tonnes
Cadmium (and its compounds): 6 tonnes
Cobalt (and its compounds): 475 tonnes
Phosphorus (total): 41,640 tonnes
Copper (and its compounds): 18,413 tonnes
Antimony (and its compounds) 14 tonnes
Manganese (and its compounds): 20,988 tonnes
Mercury (and its compounds): 3 tonnes
Selenium (and its compounds): 46 tonnes

You're saying that you'd drink water that has been used to process this? That seems unnecessarily reckless.

It's my (admittedly limited) understanding that most everything settles to the bottom of the tailings pond and if the bottom layer remains undisturbed, the condition of the water is in a much "safer" state.

How can one be so sure that the bottom layer in that mostly emptied pond remained intact? Thats a pretty big assumption for someone with a scientific back-ground (or anyone) to make.

I deal with the disposal of large quantities of water that are similarly contaminated. Obviously the concentration and compositions can vary from batch to batch. I often hear some old Relic ask why are we paying to get rid of this water that is good enough to just release into the environment. I always want to hand them a few glasses and suggest they have some and share the rest with their grand-kids. I feel like doing the same with Brian Kynock, Bill Bennet and Christy Clark.

Well they DID stand in the way of the discharge permits to remove water from the pond (once again,not "sludge" or fines)

It's almost like they have this weird trust issue.

It's almost like they have this weird trust issue.

It's almost like some folks want to reap the benefits of operations like this,but none of the risks.

It's almost like some folks want to reap the benefits of operations like this,but none of the risks.

Yeah, I don't like management and shareholders either.

Mount Polley mine on-site disposal in 2013:

Arsenic (and its compounds): 406 tonnes
Lead (and its compounds) 177 tonnes
Nickel (and its compounds) 326 tonnes
Vanadium (except when in an alloy): 5,047 tonnes
Zinc (and its compounds): 2,169 tonnes
Cadmium (and its compounds): 6 tonnes
Cobalt (and its compounds): 475 tonnes
Phosphorus (total): 41,640 tonnes
Copper (and its compounds): 18,413 tonnes
Antimony (and its compounds) 14 tonnes
Manganese (and its compounds): 20,988 tonnes
Mercury (and its compounds): 3 tonnes
Selenium (and its compounds): 46 tonnes

You're saying that you'd drink water that has been used to process this? That seems unnecessarily reckless.

It's my (admittedly limited) understanding that most everything settles to the bottom of the tailings pond and if the bottom layer remains undisturbed, the condition of the water is in a much "safer" state.

How can one be so sure that the bottom layer in that mostly emptied pond remained intact? Thats a pretty big assumption for someone with a scientific back-ground (or anyone) to make.

Just listing tonnes is out of context without knowing their concentration, so I calculated the concentrations.

Based on those numbers, and Mt Polley's 2013 Mill throughput of 7,956,738, I calculated the average concentrations of each in the tailings impoundment. I assumed 99% of the rock entering the mill was going to tailings, to account for the amount of rock leaving the circuit in the form of concentrate. Their average grade was .295% Cu, with a 74.46% recovery rate. Assuming chalcopyrite is the main copper mineral, with a tenure of about 34%, this seems reasonable. This is a dry weight.

I then looked up the average soil concentrations of the elements you highlighted on http://www.atsdr.cdc.gov/. I first tried Environment Canada, but I found the CDC site much easier to navigate and find the same info consistently. All concentrations are in parts per million

Element: Mt Polley Concentration Average Soil Concentration
Arsenic 52 1-40
Lead 22 [HTML_REMOVED]50
Mercury 0.38 0.02-0.625
CDC considers "uncontaminated soil" to contain [HTML_REMOVED]50 ppm lead

So arsenic is a little higher than normal soil. The other two are well below.

These are, of course, concentrations within the tailings themselves. That has nothing to do with the water quality. At the most, if the tailings were fully suspended in the water that is what you would get. But if one were to take a drink from the clear water that sat on top of the tailings, or the water that entered Quensel Lake after the tailings settled out, you would need to look at total dissolved solids, not suspended solids.

In my experienced, you would be incorrect to assume that the heavy minerals would settle to the bottom of the impoundment. If you look at a cross section of tailings, you see easily identifiable layers, laid down chronologically as it is applied. You may have some settling within the top few inches that is still in some amount of suspension, but otherwise it isn't really moving once deposited. The same principals are at work in the deposition of sediments in a river delta, for example.

So, would I drink the water? I would have to see the water quality sampling data, but based on the statement of it "almost meeting drinking standards", unless that almost is one element being WAY too high, I probably would. It wouldn't surprise me if it was nutrients (nitrogen is a by-product of blasting) that are too high. This is often the case, and any bacteria and algae in the ponds eat that up quite quickly.

I have seen the sampling data for my mine, which is why I stated I would drink the water in our tailings impoundment. We have fish (bass, perch, sunfish), turtles, ducks, geese, and even the odd moose that live in and around our toe ponds. Elk graze on the grass planted for dust control.

Just listing tonnes is out of context without knowing their concentration, so I calculated the concentrations.

Based on those numbers, and Mt Polley's 2013 Mill throughput of 7,956,738, I calculated the average concentrations of each in the tailings impoundment. I assumed 99% of the rock entering the mill was going to tailings, to account for the amount of rock leaving the circuit in the form of concentrate. Their average grade was .295% Cu, with a 74.46% recovery rate. Assuming chalcopyrite is the main copper mineral, with a tenure of about 34%, this seems reasonable. This is a dry weight.

I then looked up the average soil concentrations of the elements you highlighted on http://www.atsdr.cdc.gov/. I first tried Environment Canada, but I found the CDC site much easier to navigate and find the same info consistently. All concentrations are in parts per million

Element: Mt Polley Concentration Average Soil Concentration
Arsenic 52 1-40
Lead 22 [HTML_REMOVED]50
Mercury 0.38 0.02-0.625
CDC considers "uncontaminated soil" to contain [HTML_REMOVED]50 ppm lead

So arsenic is a little higher than normal soil. The other two are well below.

These are, of course, concentrations within the tailings themselves. That has nothing to do with the water quality. At the most, if the tailings were fully suspended in the water that is what you would get. But if one were to take a drink from the clear water that sat on top of the tailings, or the water that entered Quensel Lake after the tailings settled out, you would need to look at total dissolved solids, not suspended solids.

In my experienced, you would be incorrect to assume that the heavy minerals would settle to the bottom of the impoundment. If you look at a cross section of tailings, you see easily identifiable layers, laid down chronologically as it is applied. You may have some settling within the top few inches that is still in some amount of suspension, but otherwise it isn't really moving once deposited. The same principals are at work in the deposition of sediments in a river delta, for example.

So, would I drink the water? I would have to see the water quality sampling data, but based on the statement of it "almost meeting drinking standards", unless that almost is one element being WAY too high, I probably would. It wouldn't surprise me if it was nutrients (nitrogen is a by-product of blasting) that are too high. This is often the case, and any bacteria and algae in the ponds eat that up quite quickly.

You obviously put some effort into that reply and I can respect that.

I have a few issues.

The allowable concentrations of minerals you provide are for soil. Doesn't water have different allowable levels? That being said, should your PPM calculation be taken using water concentrations rather than soil? I realize that the #'s I supplied are only one year of data and the unknown quanity of total on-site disposal hasn't been supplied. I'm not sure if your #'s mean anything.

I may have worded it awkwardly, but by settling to the bottom of the pound I did mean to the bottom of the water and not the impoundment. I don't assume that the heavy minerals would weasle their way through the layers you describe.

In a normal controlled release, the water would be skimmed from the top layer but in a catastrophic release such as this one the water could quite easily disturb the deposited layers on the bottom and carry them downstream.

Lastly as far as animals living happily around your site: We have many Orca "happily" swimming around the NW Coast that have to be disposed of as Hazardous waste when they wash up dead on shore.

I've heard water sample reports from Quesnel lake are thankfully coming back positive at this point. I'd like to see sample locations and wonder if samples at varying depths were taken right at the mouth of the creek. I'd be curious if there were sediment samples taken as well.

You obviously put some effort into that reply and I can respect that.

I have a few issues.

The allowable concentrations of minerals you provide are for soil. Doesn't water have different allowable levels? That being said, should your PPM calculation be taken using water concentrations rather than soil? I realize that the #'s I supplied are only one year of data and the unknown quanity of total on-site disposal hasn't been supplied. I'm not sure if your #'s mean anything.

I may have worded it awkwardly, but by settling to the bottom of the pound I did mean to the bottom of the water and not the impoundment. I don't assume that the heavy minerals would weasle their way through the layers you describe.

In a normal controlled release, the water would be skimmed from the top layer but in a catastrophic release such as this one the water could quite easily disturb the deposited layers on the bottom and carry them downstream.

Lastly as far as animals living happily around your site: We have many Orca "happily" swimming around the NW Coast that have to be disposed of as Hazardous waste when they wash up dead on shore.

I've heard water sample reports from Quesnel lake are thankfully coming back positive at this point. I'd like to see sample locations and wonder if samples at varying depths were taken right at the mouth of the creek. I'd be curious if there were sediment samples taken as well.

farmer is correct in that you can't look at those metal concentrations out of context. you need to account for the mass of plain non-metal bearing sediment it was mixed with, hence, farmers concentration calcs. to put things in perspective I would hazard to guess that the soil in coal harbor (which was mined for coal), false creek (heavy industrial zone), and yale town (heavy industry) contain similar concentrations of metals due to the history of the areas. i know that soils around nanaimo harbor are particularly metal laden due to the historical coal mining. also, in a recent study on the concentration of arsenic in soils in the nadina forestry district and cascades district, found some soils in natural contain up to 64 ppm As. although, this was an outlier in the survey and may be caused by local, underlying geological conditions. The average "baseline" for cascadia was reported at 13 ppm As.

so water (or any solution) has a capacity to carry or dissolve particular metals given the pH, temperature, pressure, and redox (reduction-oxiation) state of the water. these conditions will control the valence state of the metals, some valance states are non-reactive with water while others are soluble in water. for the non-reactive states, you can shove as much of it in the water you like but they will never dissolve into the water. As I eluded to in an earlier post, acidic waters will allow more dissolved metals to be stable in the water. otherwise, the metal laden water may be in contact with the water but it does not have "chemical" potential or reactivity to dissolve into the water. so the heavy metals such as arsenic and lead etc. will dissolve into the water up to the level that the pH and redox conditions allow. now, if this were a stable situation, i.e. a closed system such as tailings pond, once the water has reached the carrying capacity of whatever metal is in question things remain "stable" (although chemically dynamic). However, I would interpret (anyone else with more specific knowledge in this situation pipe in) in the case of an open system, metal laden in the sediments can continue to leach out of the sediments into the flowing water system.

so I think a major factor here for future considerations is how the water chemistry of the drainages will change through the seasons. like was mentioned previously, since mt. polley is an alkalic porphyry system, there are less acid-generating components in the tailings compared to other deposit types. but again, that is a variable I know nothing about in this specific location.

I am curious what Imperial comes up with to deal with this issue. this is still a major fuck up and does have an impact on the ecosystem around the mine site. although given the nature of the material that was released in comparison I would not consider this to be comparable to tailings in the oil sands or spills such as the exxon valdez or deep horizon. one way i think about it is that we've spilled a big jar of sand. there are bad things in that sand, but being sand it isn't going to run off and disperse rapidly all over the place like crude oil in water.

farmer is correct in that you can't look at those metal concentrations out of context. you need to account for the mass of plain non-metal bearing sediment it was mixed with, hence, farmers concentration calcs. to put things in perspective I would hazard to guess that the soil in coal harbor (which was mined for coal), false creek (heavy industrial zone), and yale town (heavy industry) contain similar concentrations of metals due to the history of the areas. i know that soils around nanaimo harbor are particularly metal laden due to the historical coal mining. also, in a recent study on the concentration of arsenic in soils in the nadina forestry district and cascades district, found some soils in natural contain up to 64 ppm As. although, this was an outlier in the survey and may be caused by local, underlying geological conditions. The average "baseline" for cascadia was reported at 13 ppm As.

I'm sure those areas you mentioned are brutal for concentrations of contaminants in the sediment. The key is not to disturb those sediments. It's obviously not great to have them on the bottom in the first place but they are doing less damage there than when suspended in the water column.

I'm having a hard time believing there wasn't some disturbance of the sediments in that tailing pond with a catastrosphic realease causing a high level of disturbance and taking the sediment from the pond down to the lake. Obviously not all of the deposited minerals would get flushed out but more than would in a controlled release.

so water (or any solution) has a capacity to carry or dissolve particular metals given the pH, temperature, pressure, and redox (reduction-oxiation) state of the water. these conditions will control the valence state of the metals, some valance states are non-reactive with water while others are soluble in water. for the non-reactive states, you can shove as much of it in the water you like but they will never dissolve into the water. As I eluded to in an earlier post, acidic waters will allow more dissolved metals to be stable in the water. otherwise, the metal laden water may be in contact with the water but it does not have "chemical" potential or reactivity to dissolve into the water. so the heavy metals such as arsenic and lead etc. will dissolve into the water up to the level that the pH and redox conditions allow. now, if this were a stable situation, i.e. a closed system such as tailings pond, once the water has reached the carrying capacity of whatever metal is in question things remain "stable" (although chemically dynamic). However, I would interpret (anyone else with more specific knowledge in this situation pipe in) in the case of an open system, metal laden in the sediments can continue to leach out of the sediments into the flowing water system.

so I think a major factor here for future considerations is how the water chemistry of the drainages will change through the seasons. like was mentioned previously, since mt. polley is an alkalic porphyry system, there are less acid-generating components in the tailings compared to other deposit types. but again, that is a variable I know nothing about in this specific location.

I'm glad to hear that the PH of the water in the pond is such that it will help mitigate the level of contaminants in this situation. This is something that I have learned from both you and Farmer today.

I am curious what Imperial comes up with to deal with this issue. this is still a major fuck up and does have an impact on the ecosystem around the mine site. although given the nature of the material that was released in comparison I would not consider this to be comparable to tailings in the oil sands or spills such as the exxon valdez or deep horizon. one way i think about it is that we've spilled a big jar of sand. there are bad things in that sand, but being sand it isn't going to run off and disperse rapidly all over the place like crude oil in water.

Major fuck-up indeed.

I read that most levels of bad elements aren't high, except for selenium, which was about double the acceptable limit.