HYDRO29817

• Permit No: C1981034
• IBM Index Class Name: Hydrology
• Doc Date: 9/6/1983
• Doc Name: GRAND MESA COAL CO FN C-034-81 SEDIMENT POND CERTIFICATION
• From: GRAND MESA COAL CO
• To: MLR
• Permit Index Doc Type: PROF POND CERTIFICATIONS
• Media Type: D
• Archive: No

~- Grand Mesa ~
Coal Company

First end Columbia
P. O. Box 226
Delta, Colo. 61416
Office: [phone]
Mine: [phone]
August 30, 1983 RECEIVED
Dan Mathews
Reclamation Specialist
Colorado Mined Land Reclamation
1313 Sherman Street - Room 423
Denver, CO. 80203-2273 -
SUBJ: Grand Mesa Coal Company, File # C-034-81
Sediment Pond Certification
Dear Dan:
sEP s )s83
f81NED UND RECUMAiION DIVISION
Colo. Debt of N~turol Resources
In response to problem #034-83-04 as noted in your July, 1983
inspection report, this letter is to certify the construction of the
present sediment pond. Construction of the dam started August 14,
1980 and ended September 1, 1980. Inspections were made by myself and
Leroy Black of Ute Engineering on August 20th to inspect site prepa-
ration and construction material, on August 25th to inspect the
cut-off trench (10' wide x 4' deep), and on August 30th to inspect for
moisture,lift thickness, construction material, and compaction. No
problems were noted in the dam construction.
Piezometers were installed in the lower toe of the dam on
October 27, 1480. The water level in these Piezometers (P-1, P-2, and
P-3) has varied from 4' to 7.7' below the bottom of the sediment level
in the pond.
The dam, the pond embankments, and the overburden storage area
(yard extension) were hydro-seeded November 18, 1980 using 1000# wood
fiber mulch/acre and the stabilizing seed mix of dry land pasture mix.
The dry land pasture mix consisted of 40'6 crested wheatgrass, 20°,6
intermediate wheatgrass, 20% Russian rye, and 20% western wheatgrass,
and was applied at a rate of 20#/acre. The vegetation success has been
slow, but no excessive erosion has occurred.
During construction of the dam, special attention was paid to the
dam location and the embankment slopes to achieve the design volume.
Present volume calculations show that an error was made in not closely
observing the starting elevation. The initial design elevation did
not take into account the coal stack in the drainage. A recent air
photo shows a 4' elevation difference in the crest of the dam, compared
to the designed crest. The water volume, according to the recent