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5~ ~ . • • <br />STIPULATION NO. 38 <br />Twentymile Coal Company will submit a technical revision or <br />combination of revisions within 60 days of permit renewal <br />issuance (RN-02) addressing the probable hydrologic <br />consequences section of the Fish Creek Tipple, the addition of <br />an alluvial well on Fish Creek, the mapping of the post-mining <br />land-use for the Foidel Creek mine and the Eckman Park mine <br />(C-81-071), and correction of pages as required. These issues <br />correspond to those issues outlined in the Division adequacy <br />review for RN-02. <br />Please refer to the information submitted with PR-03 which <br />will allow the Division to determine that this stipulation has <br />been complied with. <br />Hvdrolo <br />1. Exhibit 32 predicts for the period 1992-1999 a maximum of 338 <br />6L0 mg/1 on lower Trout Creek, 166 mg/1 on the Yampa RIver at <br />~~~yo' Hayden, and 471 mg/1 on lower Fish Creek. Has this Exhibit <br />been updated for PR-03. If not, please update this Exhibit to <br />reflect new predicted conditions on these three stream <br />segments. <br />2. Text on pages 2.05-118(u) and 2.05-118(z)(1) incorrectly <br />ty5 states that the loss of water in well 006-82-48A was due to <br />k~°o~~~ well failure rather than dewaterinq due to subsidence. Unless <br />TCC can support this contention, these statements need to be <br />y~i'~~~~a.~ ` ~ corrected of modified to be accurate. <br />logs ~s~ <br />~- ~ What additional sampling has been done on the water inflows <br />aa'~a~ ~ ~~px from the fault along 9R gateroad? (p. 2.04-20(a)) Has <br />~ ~ ~ye~{` equipment been repaired to allow EC and pH to be recorded for <br />~~a this inflow? <br />s <br />°w~' 4. The hydraulic conductivity value listed on page 2.05-118(z)(3) <br />is incorrect. <br />5. The Division notes that low to average hydraulic conductivity <br />values were used to calculate average to maximum inflow <br />1~5 ~ values, respectively. Since hydraulic conductivity is the <br />Nra ~^ most important parameter in this calculation, why were average <br />~ ~~ 1~~ values used to calculate maximum inflows? <br />~` 6. Related to the above issue, the Division used near-maximum <br />discharge values for the EMD mine discharge in salinity <br />calculations conducted as part of the CHIA. This discharge <br />will operationally be handled by a 350 gpm pump located at the <br />dewaterinq borehole. Please be advised that increased <br />discharge or pump volume increases from this site will <br />require a technical revision to the permit with modification <br />the PHC portion of the permit at a minimum. This will allow <br />the Division to evaluate impacts to the hydrologic balance <br />