PERMFILE47183

• Permit No: C1981029
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: APPENDIX 2.05.3-10A SEDIMENT TRAP & CULVERT DESIGN SUN COAL CO MEADOWS 1 ROUTT CNTY COLO
• Media Type: D
• Archive: No

F
EUGENE M. SHEAREA,P.E.
CONSULTING GEOLOGIST
5720 South Jasmine Street
Englewood,CO 80111-1525
[phone]
27June94
Mr. Bryan Archer
Sun Coal Company
10200 West 44th Avenue
Wheat Ridge,CO 80033

RE: As Functionine Maooine of the Northwest Sediment Trao
Meadows No.l Mine. Sec.23.T6N.R87W Routt Couniv.Colorado
Dear Bryan:
Following my inspection of the Sedimentation Ponds at the
Meadows No.l Mine on 1June94 I acted on your request to
prepare an "AS FUNCTIONING" drawing oP the subject trap. At
the time my survey equipment included a Brunton compass, a
100 foot tape, a hand level and a Jacob's staff. Accuracies
accomplished with this survey instrumentation are estimated
as follows: horizontal measurements, plus or minus 0.1 foot;
azimuth measurements plus or minus one degree; vertical
measurements plus or minus 0.15 foot; and embankment slope
ratio determinations plus or minus 0.1.
On the accompanying drawing, Reconnaissance Plan Map and
Profiles, As Functioning, Northwest Sediment Trap, the
embankment configuration is projected from profile to
profile. Similarly, the water body perimeter is projected
Yrom control point to control point. The embankment is semi-
circular in configuration and the upslope of the terrain to
the east completes the containment structure. Inside
embankment measurements are: B to F 67.5 feet; C to G 59
feet; A to E 66.7 feet; and D to G 71 feet. The average of
these measurements is. 66 feet. The pond diameter is
estimated at 40 feet. If a five foot distance is used
between the pond surface and the embankment crest, the trap
volume calculates to be 11,031 cubic feet or 0.2532 acre
feet, a volume slightly higher than the original permit
design volume. If the low elevation on the north embankment
is taken into consideration, a 4.2 foot water to embankment
crest measurement results and the volume calculation reduces
to 9,266 cubic Feet or 0.2127 acre feet, slightly less than
the original design volume.
The design dewatering culvert for the trap was sized at 18
inches, a diameter calculated to convey a 100 year 24 hour
design storm event. The installed culvert is 20 inches in
diameter.