Pollution gets plugged at Leadville mines
LEADVILLE – The Environmental Protection Agency’s curtain is about to fall on the last of the bad actors on Strayhorse Ridge.
Beginning in May, work will begin to eradicate two sources of water contamination just east of the Leadville’s city limits. Removal of contaminants at the Robert Emmet Mine on East Fifth Street and the Ponsardine Mine, along East Seventh, should be completed in early July. The projects will bring to a close years of remediation in the EPA’s “Operable Unit 6,” a 3.5 square-mile area that encompasses most of the Leadville mining district.
In May, crews from Frontier Environmental, Inc. will attack mine waste material located behind the wooden crib wall at the Robert Emmet Shaft. There, water from rain and snow reacts with chemicals in the waste rock to release lead and zinc. The resulting compound appears as a white or yellow coating on the timbers alongside County Road 1 at the mine site.
“This is the obvious actor – the guy that’s putting the metal out,” said Mike Holmes, EPA site manager for the California Gulch Superfund Site. “The jury verdict is out to do the work and get out of town.”
Also in May, work will begin to remove similar contaminants from the Ponsardine, where the pile of waste rock towers over the storm drainage ditch on the south side of Seventh Street. Water running over the surface of the mine dump dissolves metals in the rock as it flows toward town and eventually the Arkansas River.
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At the Robert Emmet, up to10 feet of material will be removed and hauled by truck to a storage site at the Asarco Black Cloud Mine, located in Iowa Gulch. A water-proof barrier will be installed to prevent water from coming in contact with deeper material. The void will be backfilled with clean rock. The remains of a historic wooden ore bin will likely be removed to get to the contaminated ground behind it.
The structure will be replaced with a modern retaining wall designed to hold back the earth on the north side of the road. Work should be done the first week in July.
A short distance to the north, pollution caused by the 1903-era Ponsardine Mine will be dealt with. The history of the lode suggests that removal of the entire waste rock pile might not be necessary.
Originally sunk as an exploratory shaft by an early-day Leadville priest named Father Ponsardine, the operation uncovered little in the way of rich ore, and was shut down. Apparently, the last of the rock to be removed is to blame for the modern-day contamination. The sulfide ore was deposited mainly on the surface of the dump, where rain and melting snow pick up the metals.
Work crews will carry out what Holmes calls “surgical removal” of only the metal-bearing layer of the 17,000 cubic-yard pile. The material also will be trucked to the Black Cloud Mine for disposal.
Even though work will take place next to both county roads just east of the city limits, the projects are not expected to interfere with vehicle traffic.