Before … and after. Pic taken from the same spot
The view from Mt Donaldson about 3 pm on the Monday
Owner of the Savage River mine, Grange Resources is working with the Tasmanian Environment Protection Agency to assess the impact of a tailings dam spill just over a week ago.
The tailings dam at the mine normally flows into Main Creek, but in this case, a larger than normal flow occurred that had the potential to take fine material from the tailings dam into the creek.
Grange do not process any of the extracted metals on site, so any impact on the environment will be caused by already present substances – possibly sulphur.
General Operations Manager Ben Maynard says they are still assessing what material may have come out of the tailings dam.
TASMANIAN COUNTRY HOUR – TUESDAY 26 March 2013
SPILL AT SAVAGE RIVER MINE – GRANGE RESOURCES
Interviewer/Presenter Sally Dakis: Let’s turn now to Mining: Grange Resources which experienced a spill at its tailing dam just over a week ago, Now Grange Resources doesn’t process any extracted metals on site so any impact on the environment would be caused by ‘already present substances’ and possibly sulphur. Now the General Operations Manager of the Savage River mine, Ben Maynard says they’re working with the Environment Protection Agency to access the impact of the spill.
Ben Maynard: We had – unfortunately – an unplanned event with our tails dam. We operate a tails dam that naturally overflows… or is part of our process to overflow alkaline water into what’s called ‘Main Creek’. That Main Creek stream is a highly degraded stream from, ahh… previous operations. Ahh, it’s… it’s one that is acidic and has metals that are leaching out into the water system. And so, by us operating our tails dam we are able… we are able to allow this alkaline water to flow into that, ahh… that Creek. And that prevents or slows down the leaching of those metals … and so our operations and intent is to improve the environment from those past operations. And that’s something that we do in conjunction with the Government.
The issue that we had the other day was that we had a small differential in the pond which allows the silt to settle into before it flows over and ahh… we saw, ahh… an event that caused a… a high velocity flow. Not a flow that’s out of keeping with some of our normal flows over there – our winter flows. But, ahhm… that wasn’t the issue. But the potential was there to take fine material over the dam and put it into the Creek.
Sally Dakis: Now we know the EPA has been investigating it. What are their findings about the impact of this spill?
Ben Maynard: It’s, ahhm… pretty early days. We’re obviously working very closely with the EPA. We’re providing them with information we’ve had them on site to do samplings of the sites. Ahhm… and we want to work with them to understand what, if any, the impact there is. Ahhm, we… we’ve worked with them initially so we’ve given them our take on how… how the incident occurred; what the circumstances surrounding that and what we did to immediately remediate that issue. And… and we’ve had some really great feedback from the Director [of the EPA, Alex Schaap], he was very pleased at the way we responded comprehensively and rapidly to that situation. Ahh, internally we are doing our own ‘root cause analysis’. We take very seriously our impact on the environment and how we’re trying to improve, ahh… the land around us. And so our ‘root cause analysis’ will help us to show where we can continue to improve and, ahh …. make our systems better.
Sally Dakis: I may not get the wording exactly right but you said that ‘the velocity of this water’ wasn’t unheard of. Does that mean it might happen again?
Ben Maynard: Ah… it…. it happens all the time. The issue isn’t about the water flow. The water flow is good. If we had no flow in that Creek that Creek would become acidic – down to a pH of 4 – and start to leach metals. So it is a good thing that our tails dam is flowing over… and that water… that alkaline water is flowing into Main Creek.
The issue is when it’s an unplanned vent and it happens suddenly, it can take, has the potential to take, fine material with it. And that’s not what you want in the Creek.
Sally Dakis: And that ‘fine material’ contains what?
Ben Maynard: We… we’re still working out … the extent of … characterising that material to see what it has… if, if any of it has gone in… how much of that there is. So we’re still working on that and the EPA are working on that as well.
Sally Dakis: Is this material that is actually in the tailings dam that’s been there historically or is it material that is coming from your mine now.
Ben Maynard: Yeah… this material is from our, ahh… live tails dam. Ahhm… one of the great things and why this water is so alkaline is because as we mine, we’re mining a lot of carbonate rock and a lot of that gets mixed in with the ore that we mine. So our tails dam has a high pH which is… which is 7 to 8. And that… that’s the great thing about it; by that overflowing into Main Creek; it’s buffering that, that historical legacy acid production.
Sally Dakis: So this this the first time your mine in recent times has had this kind of impact.
Ben Maynard: We haven’t defined what the impact is, but… yes, I haven’t seen anything like this in the last 15 years. We… we… we take great pride in the way we manage our impact on the environment; the way we manage any water that flows off. We actually encapsulate all run-off from our mine and even the previous operations we pipe that into a central location so that can settle out… ahh, be neutralised by our carbonate material, and even flow across into Savage River.
So that’s… I guess the context of this is, ahh… that there are a lot of legacy issues … that was a highly degraded creek and, and… this highly alkaline flow is helpful. But what we’re concerned about is this fine material and what that might introduce.
Sally Dakis: And just in conclusion, the EPA has suggested the tailings contain sulphur and one of the things it might do is present a risk to local aquatic ecology. Do you agree?
Ben Maynard: Ahhh… our tails do contain sulphur. It depends on what’s come out of the dam. And that’s what we need to understand, but yes, that… that creek doesn’t have aquatic life in it at the moment. It’s, it’s… very… it’s highly degraded. So yes, sulphur in tails is an issue.