Summitville Mine 

Narrator: Like a storm drain cut deep into the mountain water runs through this 

abandoned mine shaft as it has for years. And although the water is highly 

contaminated, the investigation underway is not focused on the contaminant 

specifically, but rather on the presence and nature of any fractures in the 

adjacent rock where the water could migrate. 

The problem is that the oxygen-rich environment in the shaft enables the water 

moving through it to readily leach metals such as copper and zinc from ore veins 

in the surrounding walls. If allowed to leave the mountain untreated, the water 

would be toxic to life downstream. By plugging the shaft, engineers believe they 

can limit the flow of contamination exiting the mine and at the same time diminish 

the process that causes it. 

Greg Powell, Environmental Scientist / ERT: Where the water that's moving 

through the old tunnels that's being re-charged from melt, snow melt on the 

mountain and also from precipitation events, it moves through these old mine 

tunnels. And this water's oxygen-rich and the chemical reaction with the sulfide 

bearing minerals in those old tunnels, it picks up metals and discharges out of 

the mine shaft. By plugging the adit. It'll basically back up water behind the plug, 

which you won't have that oxygen-rich water in contact with the sulfide-rich veins. 

There will still be some metals picked up in that water and still be some 

movement of the contaminated water through the fractures, however the loading 

will be significantly reduced. 
Narrator: With the adit plugged pressure will force the water to follow a different 

coarse through the rock. Mapping the fractures or cracks across the subsurface 

of the mountain prior to closing off the shaft, will help to predict where, and at 

what volume the water may reappear. But the site encompasses over 500 acres 

and with a mining history that has shaped and reshaped the mountain, mapping 

will be difficult. 

Hays Griswald, On-Scene Coordinator, US EPA: This area, this mineral 

district was originally discovered in the 1870s, early 1870s. And originally they 

discovered gold in the creeks and it was placer mined. Then they discovered 

these load ore bodies up here, the veins, that they mined first by a small, shallow 

open pit or glory hole as they call them. Then they went underground in tunnels 

or drift mining and followed the veins. That occurred off and on through the early 

1900s all the way up to the 1940s, a little bit in the 1960s, and then there was 

quite a bit of exploration in the 1970s up here. And that last part of the 

exploration was looking for a low grade gold deposit and heap leach operation. 

Narrator: The Summitville Mine remained active until October of 1991. At that 

time EPA Region VIII stepped in to maintain the wastewater treatment plant and 

to begin the long process of restoring the site. Mapping the subsurface fractures 

and consequently plugging the [Reynolds adit] are just part of that overall effort. 

To locate and verify the fractures, 2 different technologies were used. SP or self 

potential which took readings from within the mine shaft and VLF, which required 

a number of traverses to be walked across the expanse of the hillside. 
Steward Sandberg, Geophysicist: Okay, we're running VLF, it stands for very 

low frequency. Its an electromagnetic method. We're detecting radio waves that 

have transmitted from military sites, submarine communication sites across the 

different points. We're using a Seattle station but we're basically using that as an 

electromagnetic signal and we're mapping the scattering of that field do to stuff 

under the ground. A fracture is sort of a general term for a geologic condition 

where the rocks open up and water can move through that uh opening. Basically 

if we have a fault of fracture zone its going to conduct electricity a lot more than 

the rock to the side of it so that we'll concentrate the magnetic field in that 

conductor, in the fracture zone. And if we map that radio field, the VLF signal 

over this site, the transmitter's so far away that it should be uniform so deviations 

from that uniformity will, will indicate fracture zones are possible. 

Narrator: The leaching of metals is a direct consequence of the presence of 

oxygen coming in contact with the water. Fractures which are found to be water 

filled are less likely to trigger this decay. 

Rich Henry, Ecotoxicologist: Should that groundwater back up into an area 

that doesn't allow it to come in contact with oxygen, then those chemical 

reactions would not occur and the groundwater may be discharged in a natural 

way, very similar to the way it was discharged prior to the mine being dug in the 

ground in the first place. If the groundwater backs up into areas that contain 

oxygen, that will trigger those chemical reactions that create the acidic solution 

that leaches the metals from the rock and if that solution is then discharged to the 

stream, we're back in the same position we were prior to plugging the tunnels. 
Narrator: Water continues to pass through the mine as a result of rain and snow 

melt from higher elevations. At present the EPA has a wastewater treatment 

plant in place to treat the water coming out of Reynolds adit. 

Hays Griswald, On-Scene Coordinator, US EPA: Right at this particular time 

the adit is flowing at 300 gallons a minute so we are treating all the flow from the 

adit. During the spring the adit flow goes up to as much as this spring, 1,000 

gallons a minute. So we obviously didn't catch all of that and that's part of the 

idea of plugging the adit to even if we don't get the attenuation in the rock, if 

that's not possible, we at least have the plugs in the adit for surge control and be 

able to at least back up and store all of that flow in the mountain and treat it at 

the rate we are able to. 

Narrator: When the water leaving the adit exceeds the capacity of the treatment 

facility, its channeled directly into the same stream as the treated water. Once 

there, the contaminants are free to move downstream where they pose a 

significant risk. 

Rich Henry, Ecotoxicologist: There are a multitude of contaminants in this 

water including metals and cyanide. In addition the water is probably at a low pH, 

somewhere around 2 to 3, and that has a number in negative consequences. 

Primarily its toxic. Its toxic to most forms of aquatic life including the macro 

invertebrates that inhabit the stream bottom, any fish that may inhabit the water 

or any organisms that might use this stream as a water source. There's other 

effects as well. When this contaminated water is put onto crops and crop land it 
has a tendency to accumulate in the soil and then potentially it'll accumulate into 

crops and that can have negative effects on the people that are consuming the 

crops as well as any livestock that might uh graze in those areas. 

Narrator: When this phase of the operation is completed and the results 

forwarded to the Regional EPA, engineers should have a clear idea of whether or 

not plugging the adit will minimize the amounts of contaminants flowing 

downstream. 

Within the first day of mapping 3 significant fractures were located, one as deep 

as 300 feet. This almost instant access to details of subsurface creatures allows 

the team to focus their efforts so that their findings will not only indicate whether 

plugging the adit will work, but where a plug will have the greatest positive impact 

on the environment.