APPCOR11314

• Permit No: C1981048
• IBM Index Class Name: Application Correspondence
• Doc Date: 2/9/1981
• Doc Name: MEMO-TRINIDAD BASIN MINING CO FN 79-53
• From: MLR
• To: MIKE SAVAGE
• Media Type: D
• Archive: No

~ _
STATE OF COLOR4D0 RiC HnRD D. ~• Govm m. III IIIIIIIIIIIII III
DEPARTMENT OF NATURAL RESOURCES
D. Monte Pascoe, Executive Director
MINED LAND RECLAMATION
423 Centennial Building, 1313 Sherman Street
Denver, Colorado 80203 TeI.i303) 839-3567
David C. Shelton
Director
T0: Mike Savage
FROM: Rich Domingue
DATE: February 9, 1981
MEMORANDUM
RE: Trinidad Basin Mining Company, File No. 79-53
Evaluation of TBM's responses to adequacy concerns of December 8, 1980.
1) Haul road as shown will require roadway drainage. This reviewer
questions whether this is the best solution from the operator's
point of view.
2) Overburden stockpile should be granted a small area exemption.
3) Ditch 15-D2 needs maintenance as seen on our last inspection
trip of Janaury 29, 1981. With ditch in good condition, sediment
control should be adequate.
Responses to Bob Liddle's comments of December 8, 1980.
1) Application of the method used is inadequate. TBM should
review SLS TR-55 Appendix E-5. The sh~p~ of the watershed
must exhibit the relation of ~- = 209a There is an
adjustment described on Page E-5 which will correct for
variances from this relation. TBM should recalculate all of
their runoff values using this correction.
2) Rip rap D50 of 7" appears more appropriate for an estimated
ditch outlet slope of 30%. Significant movement of material
is likely if suggested rip rap size of 2-4" is used.
3) Proposal is sensible and correct.
4) Proposal is sensible and correct.
5) Estimated ditch velocities remain relatively high. Compaction
of ditch walls is mandatory for ditch stability under conditions
of 10 year 24 hour event. Estimated ditch velocities using
TBM's figures is 5-7 fps.