REP12117

• Permit No: C1981025
• IBM Index Class Name: Report
• Doc Date: 1/28/1988
• Doc Name: RECLAMATION OF THE THOMPSON 2 COAL MINE AT THE SNOWMASS COAL MINE SITE
• From: MLRD
• To: CANDY THOMPSON
• Media Type: D
• Archive: No

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STATE OF COLORADO
Roy Romer, Governor
DEPARTMENT OFNATURAL RESOURCES
MINED LAND RECLAMATION DIVISION
FRED R. BANTA, Director
DATE: January 28, 1988
T0: Candy Thompson, Coal Reclamation Specialist
FROM: David Holm, Inactive Mine Reclamation Supervisor
RE: Reclamation of the Thompson No. 2 Coal Mine at the Snowmass Coal Mine
site
As you know the Inactive Mine Reclamation Program designed and constructed a
passive mine drainage treatment system at the abandoned Thompson No. 2 Coal
Mine located near Carbondale, Colorado. The Thompson No. 2 PMDT system was
constructed early in 1985. Prior to aqy work at the site, the Inactive Mine
Program received approval from the Colorado Water Quality Control Division
(WQCD) to construct the Thompson PMDT system as amine drainage abatement
feasibilty study. Potential requirements fora NPDES permit were waived by
the WQCD. Also, negotiations between Colorado's Title V and Title IV
reclamation programs and officials at the Snowmass Mining Co. occurred in
which it was decided that the AML project area should be removed from the
permitted area of the Snowmass Mine. Accordingly, the Inactive Mine
Reclamation Program assumed reclamation responsibility for the disturbances
created by the passive mine drainage treatment project.
The passive mine drainage system incorporates three basic facilities. A
constructed wetland receives drainage from the abandoned Thompson No. 2 Mine
portal. The purpose of the constructed wetland is to remove heavy metals by
adsorption into the organic substrate of the constructed wetland and by plant
uptake. The mine drainage filters through this constructed wetland and
discharges into a 4 inch diameter ABS plastic pipe which conveys the drainage
down a steep hill slope into a limestone filled channel. A series of drop
structures were created in the limestone filled channel in order to provide
aeration and to exsolve carbon dioxide from the mine drainage. This channel
conveys the drainage to Thompson Creek.
The PMDT system constructed at the Thompson No. 2 Coal Mine has been extremely
valuable in elucidating the design and construction principles which are
useful in passive mine drainage system applications. This system was beset by
many environmental and technical problems. Construction was accomplished
during harsh winter conditions. After completion this system experienced
minus 30°F operating temperatures and freezing of water in conveyance pipes
was a problem. Unprecedented variations in flows discharged from the mine
portal occurred during the first year of operation. During the 20 years of
observed flows from the mine preceeding construction of the treatment system
423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203-2273 Tel. [phone]