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<br />Permit #: r-C- L9 -G~i onfidental?: /J R. Dowsett <br />Ph <br />D <br /> <br />Class: <br />v, <br />pe-Seq.: , <br />. <br />. <br /> <br />' <br />From: i-gyp De.~/arc Z16c~ <br />;ulting Geologist <br />Ptic' RECEIVED <br /> <br />Doc. Name: 'ac ~ L Glen A Drive <br />G.(,u(' Yr <br />Doc. Date (if no date stamp): ~Z-~ - >d, Colorado 80215 <br /> 13) zs~-SZOS SEP 2 41984 <br /> nber 13, 1984 <br /> DINED LAND RECLAMATION DIVISION <br />To: Anne Vickery, Colorado Mountain Club Colo. Dept. of Natural Resources <br />Thomas Lustig, National Wildlife Federation <br />Subject: Homestake Mining Co. Pitch Project Reclama tion Flan Amendment <br />Supplemental Report: "Assessment of Potential for Environmental <br />Dispersion of Constituents of the Reclaimed L aw Grade Ore Piles <br />at the Pitch Mine", D ames and Moore, October, 1983 <br />INTRODUCTION <br />The study of the potential for dispersion of elements from the <br />low-grade ore stockpiles at the Pitch h?ine as reported on by Dames <br />and htc•ore has serious shortcomings as :uas noted in my memo of August <br />11, 1?84. Some of these shortcomings have been addressed in a respon=_.e <br />to the adequacy re~:iew of the Mired Land F:eclamation Division ihtemo <br />from Jerri Danr.•i, HMC, to Mark: Loye, MLRD, August 31, 198-??. Sam= of <br />±he .more serio! <s questicr.s ,however, were rot answered. <br />The shortcomings that were not addressed generally concern 3sp:ects <br />of ±he potential disper=_icn of elements that were given only super- <br />ficial consideratior. in the study. <br />The detailed ccmments that are given below are !::eyed to the <br />various sections of the report Ord include pans references. Some of <br />the common*_s are the sarr:e as given earner. These comments were not <br />ddr~ssed _,. the response to the adeq~:acy r=view. <br />SUMMAF;Y OF MA•~OF. ~ONCE~~JS <br />------- -- ----- -------- <br />The sbudies of dispersion of elements from the lor+-grade stock:- <br />piie~ __sm tc ha~.e been made to _!;stify a de~ _ th,.=.t :va=_. .31r~ady <br />chosen.cThey :~~ not seem to have'been !;sod in~~=-e?ecti:^.g the design i:i <br />the first plat=. More complete studies _. t?-:e effects ~f dispersion <br />sho!;ld 6e used _.. formulate a design that :v ill a:inimi~e t:^,e ,.--=gati-•re <br />o iScrtS of dispersion of potentially hazardous ___...ents. It is 'agate <br />possible that ~:he optimum configuration for the6 _:_~ may __ less <br />_~stly to cons*_r!:ct and posssss fewer '_eng-ter ,m ,..=.inter,~,nce oorcerns <br />than the design p-e=.e.^.ted in ±-:e amended plan, <br />Th.e r_pc•r t ..ould be _mproved immensely if e::periments ar.d *_ests <br />:-sere de=_.:=gibed ir, ret_=-il 3nd complete re=.ults given. This da*_a _culd <br />be presented in appendices with summary data included in the main text <br />of the report. Also, very little analysis is giver: for constituents <br />other than radion~:clides. The data in the repor*_ indicate that other <br />potentially hazardous elemen*_s are presE.^.t in sigr!ifi~ant quantities <br />in the ore materials and leach.3tes and these sho!Qd be studied in mor-e <br />detail. <br />The study should inves±igate a larger range of precipitation <br />events because the infiltration conditions will vary greatly with <br />different types and durations of events. The worst case for one type <br />of dispersion is not necessarily the worst case far others. Also, the <br />study should use hydrologic data from the site or, at least, from a <br />