PERMFILE139435

• Permit No: C1981019
• IBM Index Class Name: Permit File
• Doc Date: 6/14/1985
• From: MLRD
• To: COLOWYO COAL CO
• Section_Exhibit Name: Gulch A sed pond
• Media Type: D
• Archive: No

-19-
Mr. Richard Atkinson
• May 14, 1981
Page Five
s
The Taylor Gulch Pond and Gulch A have Leen revised to acccmmodote the
revised sediment volumes resulting from revised sediment delivery ratios cnd
revised CS factors.
5. Working area percolation pond: This pond is a component in the sanitary
waste disposal system anJ as such is not connected v+ith storm drainage a the
sedimentation ponds,
b. Drainage from disturbed areas: The ar;~as desa~ibed in this point are drained
to the Streeter Gu ch and Gulch A detention Fonds by the use of berm ditches,
terrace or contour ditc'r,es and the Ecst Collection Ditch. In the crew nett
Streeter Gulch berm ditches ct vertical intervals of 1CC' ere employed to terry
the drainace along the berms in a northernly and v+esternly direction to the
Streeter Gulch channel. In the Section II fill either terrace ditches or contour
ditches v+ill be used to conduct dreinage to the Gulch A south ditch (Drainaae
No, 5) and thence to Gulch A detention pond. A small area in the vicinity of
the Gulch A n~ th ditch (Drainage No. 4) wiil be also conducted arena terrace
ditches or con=cur ditches to the Gulci ~. north ditch and thence into the Gulch A
• detention pond, 71ie Eestside collet;;=^ =tc~;, a portion of whic:-+ is cost-ucted
cnd operatirg.in Section 2,..callecs r_~nc;: „cm thz fill areas below the Icst berm
and from construction roads and ccnduc`s this nmoff to the 69UJ berm o; the
Streeter Gulch fill. As this ditch is extended with the mine procression into
Section II a portion of the ditch will discharoe flow into Gulch A drainace system
cnd thence into the Gulch A sedimentation pond.
7, Sectir.n II Permanent Diversions: The Adequacy P.eviev+ inquires about the design
of diversions to e located in conjunction with the Section II fill. The original design
of the=_e diversions v+as a single diversion channel looted along tie south boundary
of the Section II fill. Data and sketch of this channel c-e given in Table 1 and
Figure 1 of Exhibit 7 to the Permit Application, The {final post mining topogrcphy
as shown on Map 19 of the Permit Application portrays a minor modification to the
original design consisting of connecting the beginning of the ditch fo the Streeter
Gulch Draimae (Drainaae No. 3), thus restoring the drainace pattern closer to
pre-mining drainage pattern, This results in a smcl{er diversion that the Diversion
No. 2 to Prospect Gulch listed in Table 1 of Exhibit 7, for which the design section
should suffice.
8. Stock \`Jater Ponds: The Adequacy Review requires compliance with applimble
ru es and standards, Ail engineering for these ponds v+ill be in compliance v+ith
the required standards.
• 2.05.4 (2)(C) 4.14 EL~c!:fillina and Grcding
5, Stream Channel Reconstruction: The Adequacy Revie•:+ reouested plans for all
stream channel reconstruction. The design datg for all stream channel reconstruction
and supplementcry ditches is civen on ~gble 1 of Exhibit 7, sketches of the ditches