Lessons Learned from The San Juan Ridge Mine
Listen to a talk given by Sol Henson from the San Juan Ridge Taxpayer's Association, during the MineWatch/CEA Foundation December Community Event. Full transcript follows.
I've been with the San Juan Ridge Taxpayers Association,since roughly the time that the San Juan Ridge Mine submitted their application to mine the North Columbia Diggins in 2012. You just saw a really a great presentation talking about what initial dewatering and maintenance dewatering of a mine operation can do to our aquifer. I'm here to give you the cautionary tale of what can happen with catastrophic dewatering that can absolutely happen with the Idaho-Maryland Mine as well.
The time I'm going to talk about is actually a previous version of the San Juan Ridge Mine, which is known as Siskon Gold that actually got permitted in 1993 to mine the North Columbia Diggins.
Now the North Columbia Diggins Mine is a very similar kind of mine to the Idaho-Maryland Mine. The Idaho-Maryland Mine is a hard rock mine and it's in fractured bedrock - in a fractured bedrock aquifer. The San Juan Ridge Mine is… it's actually in gravels, but it's cemented gravels, so actually acts very similar to what you would see with the Idaho-Maryland Mine.
I would say the major difference between the Idaho-Maryland mine proposal and the San Juan Ridge Mine is that on the San Juan Ridge, we're talking about hundreds of wells, and the Idaho-Maryland Mine is an urban area. Talking about over a thousand wells potentially impacted. So that's a massive difference.
This is a map. It's similar to the Idaho-Maryland Mine, but this is our own mine property out on the San Juan Ridge. You can see the mine property is actually this kind of rhinoceros-type shape that is in dark gray. Off to the West you'll see Tyler-Foote Road running past Mother Trucker’s. If you notice San Juan Ridge and then off to the East is Lake City Road, and right in the center - kind of the epicenter of the the whole impacts of this project - is Grizzly Hill School and the North Columbia Schoolhouse Cultural Center. I just want to point out these dark, black lines. The black lines are actually earthquake faults that run through the property at depth. These are very important because many of them have water running along it. If you breach one of those earthquake fault lines, then you can have some catastrophic dewatering events. The other thing I want to show is this two-mile boundary around the mine property. That's a zone of impact - an area where wells could be impacted by underground gold mining. This became very significant for us and I can talk about that some more. The red square is going to be the focus of the next couple slides here. Before we switch to the next slide, I'll say that…
Siskon Gold was permitted in 1993. They were only operating for a little over a year when on Labor Day 1995, They blasted into one of these earthquake fault lines and caused a massive dewatering. What you're going to see is like a topo map, but it is a map of the ground water levels of our area before the catastrophic dewatering event. Each topo line is 500 feet. And for reference, there's Grizzly Hill School. This is what our healthy aquifer looked like until the 1995 event.
Earlier, you heard that great term the “cone of depression”. The cone of all the water going into one area where they're mining and intercepting water. They intercepted a massive amount of water right there just to the south of Grizzly Hill School, and it acted as a drain - draining that whole area of water. The water table dropped around 300 feet right in the center of that cone of depression. As a result about a dozen wells were lost and nobody actually knows the amount of water that was pulled out of this mine as a result. They estimate around 6 million gallons a day, which seems like an underestimate to me, but that caused a dozen wells to go dry and untold impacts on many other wells. Grizzly Hill School and the North Columbia Schoolhouse lost their wells and Grizzly Hill School… well…
Siskon Gold never admitted fault to causing these wells to go dry. But they did re-drill about a dozen wells. What we learned about our aquifer, unfortunately, is as you go deeper for your wells, your water quality gets worse. It's not to say that there were contaminants coming from the mine, but it's just that when we re-drill to deeper depths in this area, our water quality got worse and worse. If you have a well… If you have good water quality… If you have good water quantity… It is truly a precious thing, and you never want to mess with that. A re-drilled well is absolutely no guarantee that you'll have what you currently have with your well.
Grizzly Hills School suffered with water quality issues ever since their well was re-drilled. They drank bottled water off and on for a decade. To this day they have an incredibly expensive water facility to filter their water. Also, I would like to say that there are also unknown health impacts to the impacted wells when people had their wells re-drilled. There's a number of people that have had health issues. Those are just very hard to quantify. Did that come from the re-drilling of those wells?
Here you'll see that's basically how the water levels changed. Before we had these broad topo lines running through. Then, after that project, we basically just had this big hole right where the mine project was - where all of the water got pulled into.
Some key takeaways from the 1995 event is that bedrock aquifers are highly complex. Anybody that tells you they understand what's happening in a bedrock fractured aquifer is not being forthcoming.
They're highly complex and truly, the reason we can show you all those fault lines in that map is because of this catastrophic dewatering event that we experienced. We learned that water moves along fault lines and fracture lines, Those are water bearing areas that if blasted into, can cause catastrophic events.
We learned that re-drilled wells don't guarantee a decent replacement as with Grizzly Hill School and a number of other wells. And just that permanent aquifer damage as possible. Pathways change underground when you start messing around down there.
A key approach for use was that we took this information from the 1995 event and used it to address the 2012 proposal. We pushed for - and won and effort to get a County-facilitated and approved groundwater monitoring program with input from both the mine and the community.
This allowed us to have a say in what should happen before an EIR came out. We had a water monitoring program pre-EIR for water quality and quantity within the two-mile boundary of impact around the mine property. This created a baseline for what wells look like over time. You can't just go out and do one measurement of a well. They change across the year, and they change from year to year. And they change both in quantity and quality.
Earlier, it was mentioned that the Idaho-Maryland Mine plans for 2 million gallons a day in maintenance dewatering, which is an incredible amount of water. If you think about 6 million gallons a day for a catastrophic dewatering event 2 million gallons is a third of that amount everyday coming out of your aquifer. The other thing to note - you can't really say you're going to have “one to two million gallons a day” of de-watering out of these mine tunnels… because these mine tunnels are going to be getting expanded and growing and getting bigger. The larger the mine tunnel network, the more water you're intercepting. I would imagine there's a much bigger range in the amount of water that's going to be coming out of this - especially near the end - - when they've mined it.
For the San Juan Ridge Mine, when they said they would do the final workout/build out of the mine, they were going to be intercepting seven million gallons a day. That's a million gallons a day over what they said was occurring from the catastrophic mine dewatering.
These are really big issues here in regards to wells. In conclusion, I’d like to say that our water monitoring program had about a hundred wells. It was a really great program to get a baseline for people's wells… well ahead of any kind of mine operation, and its something I encourage the community consider doing for the Idaho-Maryland Mine as well.
Thank you very much.