REV90494

• Permit No: M1988112
• IBM Index Class Name: Revision
• Doc Date: 5/25/1999
• Doc Name: BMP DISCHARGE SAN LUIS PROJECT M-88-112
• From: DMG
• To: HARRY POSEY JAMES STEVENS
• Type & Sequence: TR26
• Media Type: D
• Archive: No

~ III IIIIIIIIIIIIIIII ~
STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources
1313 Sherman St., Room 275
Denver, Colorado 80203 D I v 15 1 0 N O F
Phone: [phone] MINERAL S
FAX: [phone] &
GEOLOGY
May 25, 1999 MENING SAFETY
To: H Pose , James S evens Bill Owens
arty y Governor
GregE Watcher
From: James Dillie E.e~nuve Dne"°'
Michael B. Lung
Division Dkeaa
Re: BMP Discharge, San Luis Project, M-88-1 l2
Following is a description, as it was conveyed to me from Bill Lyle, of the possible problem with
the outflow from the BMP pipe that exits the west pit. As Harry observed during his inspection,
there is a 5-10 GPM outflow exiting the BMP pipe on the south side of the county road between
the west pit and the Rito Seco. According to Mr. Lyle, the water flows into the BMP swales and
percolates into the alluvium.
BMRI determined, after excavating the inlet drop tube and several feet along the BMP pipe, that
the inlet pipe is dry so water is not entering the pipe at the drop tube. BMRI decided that pit
water is entering the pipe somewhere between the inlet and outlet openings; probably thlu one of
the pipe joints which may have a loose, or broken, collar or, possibly, thru a crack in [he pipe.
In order to stop the flow, BMRI placed, or will place, an expandable packer into the pipe at the
outlet opening. This should eliminate the flow they the pipe. However, this does not resolve the
problem because the BMP is no longer functional. The purpose of the BMP is to convey
stormwater, or snowmelt. from the west pit into the Rito Seco drainage. !f the BMP is plugged,
surface runoff into the west pit will not be allowed to exit the pit. Part of the corrective action
should include remediation of the BMP system (repair the pipe).