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3. Regarding the question about a sulfate receiving stream standard and <br />applicability to TCC. The applicable standards for Region 12, Yampa River <br />are shown on current tables provided through the Water Quality Control <br />Division web site. The two segments of interest are 13f on Trout Creek from <br />the confluence with Fish Creek to the Yampa River, and segment 13c, from <br />the confluence with Fish Creek upstream to a point closer to the Edna Mine. <br />Both of these segments have a "WS" designation for sulfate, meaning "water <br />supply". The "WS" abbreviation means that the less restrictive of ambient <br />quality on January 1, 2000 or sulfate of 250 mg4 shall be the applicable in- <br />stream standard. However, for all surface waters with a `Water supply" <br />classification that are not in actual use as a water supply, no water supply <br />standards are applied for iron, manganese, and sulfate, unless the <br />Commission determines as a result of a site-specific rulemaking hearing that <br />such standards are appropriate. TC has provided documentation in the form <br />of agreements with the one and only domestic water user downstream on <br />Trout Creek and it is my understanding that based on this agreement, no one <br />uses water on either of these segments downstream of TCC mine water <br />discharge for domestic purposes. Therefore, I do not believe that a sulfate <br />standard limits TCC's volume or quality of mine discharge. However, other <br />stream standards do apply as shown in the tables for other constituents. <br />Permitting changes may be appropriate for that section of the permit that <br />deals with discharge limits imposed on TCC based on conductivity and sulfate <br />ratios. That may be appropriate to handle in the permit renewal. <br />4. 1 got somewhat confused reading permit text regarding flow directions on <br />some of the sections of pipeline, both existing and proposed. Some sections <br />seem to have the ability to carry flow in both directions. Hopefully, as <br />mentioned in #2 above, a map and minor text edits will resolve any questions <br />on flow direction. <br />CC: Dan Hernandez <br />0 Page 2