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<br />There are several abandoned undcrgrounrl mines within the permit area. These are shown
<br />on Exhibit 3.1-1. These mines are situatedi in the Pinnacle coal seam, located several
<br />hundred feet below the Wadge coal to be mined. The proposed surface mining se-
<br />quence should not intercept these mines, so mine water which may be contained in
<br />the underground workings will not enter any of the pits proposed at the Edna site.
<br />The proposed mining operations will not appreciably affect the recharge capacity
<br />of any identified aquifers. Since the mining sequence will not disrupt either the
<br />Trout Creek Sandstone or the alluvium found along Oak and Trout Creeks, the recharge
<br />capacity of ~ese aquifer systems will not be altered. The mining will slightly
<br />modify the pre-reaping partitioning of total runoff into surface and subsurface
<br />components. Using infiltration and water balance riata generated t,y Flc[dhorCer, et a1.
<br />(1979), the applicant has calculated thn surface and subsurface raster Aa7ance for
<br />the permit site. Under pea-mining conditions, subsurface rrcrnff accounts for approxi-
<br />mately 93e of total runoff which occurs over the permit area. Following disturbance,
<br />this figure is increased 7'=, to ^6s,. This is not consider?rl significant, and will
<br />not appreciably affect the overall hyrlrolopic balance at the Edna site. Furthermore,
<br />it is anticipated that once the site is fully regrarler7, topsoiled and revegetated,
<br />the surface and subsurface componcnCS will return to their undisturbed values. The
<br />impact is, therefore, temporary.
<br />Water Ri ohts anti Replace munt
<br />As discussed in the previous parar;raphs, ~ ground •.,+atcr users c:rist in close proximity
<br />to the permit area. These users arc situated oar the r~:estcrn side of Trout Creek.
<br />They should not be impacted significantly, .~s all spoil r,~ater leaving the permit area
<br />should enter Trout Cree}: rather than the c.~ater supply wcils. Pr the event that the
<br />mine impacts any of the ground r~;atcr users rn the acca, the nl{n(icant has committed
<br />to replacing any of the suppliers with edatcr .w..~il.,hlc throurrh the applicant's or,•n
<br />water rights (p. 4.6-G1 of th+: p:,rmit a7,nlicatinn).
<br />!~IOnr torino
<br />The ground water monitoring plan suhmit_ted in; the- applicant will be suffic.i?nt to
<br />meet the objectives of 4.r75.]' o.` the Coln; ado ,,,:~m.~rent .,:r,ulatonr program. Th?
<br />monitoring plan subnrittcd ',+? tlic a,•yrlicnnt Jr :;;rr:;;:r,' .r: _cccion ,..,.S of tiro
<br />permit application. Th~~ esistin<, ,.lluvinl ~rrou;r,! ~..,.~er ;:ell, 'PIt-1, s!:o~nr on ~~!ao
<br />2.5-21, :rill be useful roe pra~; _'ri`na ,=on;ua rati ;.~ (r,nr,-e?: .st~:rhm-rce) infoz-r..ation cn
<br />[lest Ridge, as will the .addztional a11uv_ai well :,iontiVied wi pa ye 1.5.1.7.
<br />In order to subs taretiaL~ tiro 1•r.„ircrinns .:rri c.~+n.;ir::ien:: :~,;,~In~~: in tlu• m~`rnut appli-
<br />cation, a mound wa tc r- mnni [~~rln;; 7-r ,~; r. ra fi+u~,t rn` ~;y~' ~m~ n."-~i ;,'cnrri ".•: tp tiro
<br />plan in Section 9.i~.o"".. o: ti~+ r~.~ ..it.
<br />Su Cf .J 1. ~.' :'. ~ItL'r
<br />The applicant has supplied a discussion of the probable hydrologic consequences of
<br />the proposed operation which has been summarized below.
<br />No direct disturbance of the quantity of water in Trout cr OaF: Creeks will occur.
<br />A very slight change in the qumrtitu of combined surface and subsurface runoff
<br />entering Trout Creek from the mined area may occur, as explained in the section
<br />dealing with the post-mining hudrologic balance. 'Chore will also be a small increase
<br />in the mean annual concentration of dissolved solids in Trout CreeY, as a result of
<br />mining. This wi 11 be due to the elevated TDS in the spoil water that seeps to the
<br />stream or the alluvium. These disturban ms are quantified in Section 2.5.3.5 of
<br />the permit application.
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