2009-09-28_REVISION - C1994082

• Permit No: C1994082
• IBM Index Class Name: REVISION
• Doc Date: 9/28/2009
• Doc Name: Response to Adequacy Comments
• From: Seneca Coal Company
• To: DRMS
• Type & Sequence: TR43
• Email Name: DTM
• Media Type: D
• Archive: No

SOMU ccoNal conwany Seneca Coal Com an
? p Y
September 23, 2009
Mr. Dan Mathews
Division of Reclamation, Mining and Safety
101 South 3,d, Suite 301
Grand Junction, CO 81501
[phone]
RE: Yoast Mine Permit No. C-94-082
Technical Revision No. (TR-43), Runoff Control Structures
Response to Adequacy Comments
Mr. Mathews,

SEP 2 8 2009
Division u, ?leclarnation.
Mining and Safety
Seneca Coal Company (SCC) has reviewed your preliminary adequacy review letter dated September 18, 2009
and has developed the following responses.
• 1. Because these structures will control runoff fmm disturbed areas, all of these proposed structures must be located along
drainages hydraulically up gradient from an approved sedimentation pond that has a CDPS permit. Please add a
statement to the revised text on page 11, Tab 20, to clarify that any such runoffcontnol
structures will be located will be located up-gradient from existing sediment ponds with
approved CPDS permits.
Response: A statement has been added to page 11.
2. We have received comments re
garding the proposed runoff control structures firm the Division of Water Resource Since
the structure is subject to administration it must not store water out-of-priority. All storage must be drained fmm the
runoff control structures within twenty four hours or as directed by the division engineer and/or water commissioner The
D IVR's memorandum from Craig M. L", P.E., Water Resourre Engineer, is attached
Please provide a response and appropriate design changes to comply with the DWR directive.
Response: We assume that the "out-of-priority" water is any impounded water in excess of the 2 acre feet.
As the DRMS/DWR will note from the designs, these structures are not designed to impound water only to
slow the runoff velocity to reduce potential downstream erosion. Therefore these are not impoundments as
defined by DWR regulations and guidelines.
3. The design, construction, and maintenance of the runoff control structures must ensure that water flows through the
control structure following a storm event. Certain design and construction modifications are warranted in order to ensure
• that the structures will not impound water, and will comply with the DWR request referenced in Item 2 above.
Seneca Coal Company . P.O. Box 670 • Hayden, Colorado 81639
Telephone [phone] . FAX [phone]