REP34255

• Permit No: C1981047
• IBM Index Class Name: Report
• Doc Date: 3/10/1988
• Doc Name: 1987 AHR internal memo
• From: MLRD
• To: SUSAN MOWRY
• Annual Report Year: 1987
• Permit Index Doc Type: HYDROLOGY REPORT
• Media Type: D
• Archive: No

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999
STATE OF COLORADO
Roy Romer, Gove
DEPARTMENT OFNATURAL RESOURCES
MINED LAND RECLAMATION DIVISION
FRED R. BANTA, Dlreetor
DATE: March 10, 1988, 11:30 a.m.
T0: Susan Mowry
FROM: Cathy Begej ~~
SUBJECT: ANNUAL HYDROLOGY REPORT, BLUE RIBBON MINE, C-81-047
Comments:
Water flow in 1988 was lower than previous years, resulting in higher
salinities than observed recently. The spring and underdrains have
conductivities 10-30 times higher than those in Hubbard Creek. The highest
conductivities at the site were recorded from the southernmost underdrain
which was monitored with ECS around 4800 in both April and July, 1987.
Luckily, the flow was minimal, averaging 0.5 gpm, resulting in a minor impact
to the Hubbard Creek drainage, where low flow is 1200 gpm and average flow is
15311 gpm (p.39a,Rev. 7/7/83), and conductivity ranges between 100 and 300
umhos/cm2 The Hubbard Creek surface site downstream from the mine
experiences a slight increase in conductivity, as a consequence of stream
drainage.
Blue Ribbon Coal Company recorded pHs of 4.2 and 4.1 at the south underdrain
in March and April of 1987. This is without precedent. The pHs rose to 7,3
in May and stayed at that level throughout the rest of the year, but I would
advise that we monitor it ourselves for the next couple of years in the
spring. The geochemistry of the bench material does not suggest that we
should have an acidity problem at the site.
The bench piezometers are experiencing the lowest water levels since
construction, While this is good, water levels remain above the bottom of the
coaly waste in 3 of the 4 piezometers, which was not planned in the design
submitted as a revision on April 30, 1985. In December, 1987, P 1 (north) was
7.8' above the bottom of the coaly waste, P 3 (south )was 3.5' above this level
and P4 (on the top of the bench) was 11.4' above this level. This Division
should continue to monitor Blue Ribbon's monitoring and check for cracks in
the bench in the field.
423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203-2273 Tel. [phone]