APPCOR10790

• Permit No: C1983058
• IBM Index Class Name: Application Correspondence
• Doc Date: 11/3/1983
• Doc Name: TWIN PINES SUBMITTAL ON ACCESS ROAD DESIGNS
• From: MLRD
• To: CAROL RUSSELL
• Media Type: D
• Archive: No

III IIIIIIIIIIIII III
999
DEPARTMENT OF NATURAL RESOURCES
David H. Gelches, Eaecu rive Director
Richard D Lamm
Governor
MINED LAND RECLAMATION DIVISION
DAVID C. SHELTO N, Director
T0: Carol Russell ,
FROM: Bob Liddle ,`~;'~~~~
RE: Twin Pines Submittal on Access Road Designs
DATE: November 3, 1983
.~:~
The operator is planning to upgrade the county road for use as access to
the mine. The reconstruction includes the entire 3,500 foot segment
beginning from county road 77.
The first 550 feet north of Oak Creek will be widened to 20 feet with two
roadside collection ditches. The ditches apparently drain into Oak
Creek. If field conditions warrant, we may want to see a small straw
bale filter or silt fence at the ditch outlets to collect any excess
sediment that may otherwise enter Oak Creek.
The Oak Creek crossing is apparently small and probably not capable of
passing a large event. However, since it is concrete and designed as a
low water crossing it will safely pass a 10 year event with overtopping.
In this event there may be an operational concern but not an
environmental problem.
The road segment south of Oak Creek will be widened to 20 feet and
aligned at a moderate grade. Six culverts are to be placed at 400-700
feet intervals to drain the ditch along the cut slope. The outfall of
culverts will have 6 inch diameter cobbles, 12 inch thick chutes to
protect the fill slope.
The only road segment of concern is from station 25 + 00 to 30 + 00.
This segment will consist of widening the road by cutting into the
hillside and using some of the material to fill in gullies on the fill
slope next to the channel. Cut slopes are a maximum of 18 feet. We
should caution the operator to keep all fill out of the channel bottom.
The natural stream gradient should not be altered and there should not be
any impounding of water as a result of the fill. A buffer zone from the
stream channel to the toe of the fill should be maintained if possible.
If the operator is informed of the above concern and construction is
supervised, there should not be a problem.
As this road is technically a haul road by definition, the operator will
need to submit an "as built" certification letter by a registered P.E. in
accordance with Rule 4.03.1(1)(d) after construction is complete. We
should remind the operator of this requirement.
/th
Doc. No. 6781
~~
..
423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203 Tel. [phone]