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<br />YAMPA MINING CO. <br />r.o. eox NN <br />NAYDEN, COlAM00 81699 <br />January 6, 1985 <br />• ~iiiiiiiiiiiiiiii iii <br />999 <br />~~~ ~~ <br />~~ , <br />,.i ri .V i:; ,:i <br />Ms. Cathy Re,oe j - - _. .... . <br />Reclamation Specialist `-~ <br />Mined ?and Reclaoation Division <br />Colorado Department of :Iatural P.esources <br />1313 Sherman Street, ?toom 423 <br />1lenver, Colorado 80203 <br />Dear Cathy: <br />Enclosed are three cross-sections which compare as-built reclaimed <br />topography with the approve3 posC minin8 design contours for the Hayden <br />Gulch Mine. The locations and number of cross-sections are those agreed <br />upon at our meeting at the Yampa Mining Company's office October 3, 1.98E. <br />As shown by the cross-sections, the as-built reclaimed topography very <br />closely depicts the anprove3 post mining design with only minor <br />insignificant d1EEerences. <br />Also enclosed is Exhibit D, the approved Host mining contour map. Exhibit <br />D identifies the locations, as constructer, of the ve ^vanen*_ drai.naRe <br />ditches and the te"<porary terrace ditches. The existing ditch locations <br />vary slightly Erom the 3esign Sue to haul road location, topsoil placement <br />considerations, and minor variations in the post -~iniae_ tonosranhv. <br />1s-Su'_lt cross-sections of ditch !%1 an.~ ditch ~%3 are inctuae? ;.o <br />illustrate compliance with the 3esign. <br />Also, you w111 Find co!mDentc and brief calculation summaries suhm[trad in <br />response to t1~e questions you ha;i concerninv the la c4 of rip rap ~ fining in <br />the last segment of Ditch !E?, Include3 are the results of ca1c~91ations <br />performed to determine the adequacy of. the srrale located '.n ;ratershed <br />numher 31 in routLng Elood discharge to ditr_h se~ent ?2 crithoiit requiring <br />erosion control .features. P.s can be seen from the tables, ^.he ex'_stin¢ <br />scale will not be sub;_cted to eros'_ve veLociti~s From the runoff of a 10 <br />year, 24-hour stogy event an3 ,rill, therefore, require ro rip .-ap !!ling. <br />23? 3h/! <br />