REV91917

• Permit No: C1981010
• IBM Index Class Name: Revision
• Doc Date: 8/13/1986
• Doc Name: TR 25 PYEATT GULCH AND JOHNSON GULCH DRAINAGE AND SEDIMENT CONTROL PLAN FN C-010-81
• From: TRAPPER MINING INC
• To: MLRD
• Type & Sequence: TR25
• Media Type: D
• Archive: No

•

TR9PPER MININ&IN~.
• III IIIIIIIIIIIIIIII
999
August 13, 1986
Pfs. Candace M. Thompson
Colorado Pfined Land Reclamation Division
423 Centennial Building
1313 Sherman Street
Denver, CO 80203
RE: Technical Revision No. 25, Pyeatt Gulch and Johnson Gulch Drainage and
Sediment Control Plan, File No. C-010-81.
Dear Candy:
Enclosed are the revised drainage and sediment control plans for Johnson Gulch
and Pyeatt Gulch. The new plans include designs which are based on methodo-
logies and hydrologic modelling parameters that we have agreed on over the
past few months. The enclosed document should completely replace the tech-
nical revision document that we submitted in April. Once approved, we will.
provide the Division with the appropriate number of copies.
As you are aware, our primary design objective was meeting, the effluent limi-
tation for settleable solids a s predicted by the hydrologic model. Of course,
other factors influenced the design, including existing field configuration,
practical spillway design, common construction practice, and prudent engineer-
'~. ing judgement. The predicted peak effluent settleable concentrations a[ [tre
discharge points in Johnson Gu lch, Middle Pyeatt Gulch, and East Pyeatt Gulch
are 0.0011 ml/1, 0.0022 ml/1, and 0.0007 ml/1, respectively.
For your convenience in eval uating our hydrologic models, I have included
listings of the batch input fi les, along with copies of each file on a flexi-
ble disk. The disk files are named JOHNSON.DAT, hiPYEATT.DAT, and EPYEATT.DAT
for the Johnson model, Afiddle Pyeatt model, and t}~e East Pyeatt model. The
listings of [he batch input fi les follow the output listings for each model.
Enclosed also is a revised permit page, Appendix Q, Specifications for
Impoundments, which addresses pond construction practices. Once approved,
this page shold replace the existing page in the Division's copies of our
permit application.
If you have any questions or comments regarding these plans, please feel free
to contact me. We would appr eciate prompt approval so we can complete con-
struction of the 19iddle Pyeatt dams during [he 1986 construction season.
Sin
cer
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ly,
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Collin R. Fay
Project Engineer
CRF/jb
Enclosures
pc R.L. Fanyo, WDBST
J.C. Kubic, CDOH
L.W. Henderson
P.O. Box 187 Craig. Colorado 81626 [phone]