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Mr. Ralph Lopez <br />June 9, 1994 <br />Page 4 <br />7. As first stated in the Division's February 9, 1994 adequacy <br />letter, the Division is still concerned about the possibility <br />of the mine's incline getting clogged up by the coal slurry, <br />given the proposed 40~ solids concentration of the slurry. If <br />the rock tunnel clogs up, the mine water might possibly not <br />discharge through the portal, as would be required by MSHA. <br />With the portal not discharging, hydrostatic head may build up <br />behind the portal and eventually blow out the portal <br />seal.Please describe what methods Basin will use to prevent a <br />possible blockage of the workings and, if a blockage occurs, <br />what steps will be taken to clear the blockage. <br />S. In accordance with Rules 2.05.3 (10)(a) and 4.11.3, this <br />technical revision can not be implemented unless the operator <br />has secured approval from MSHA. Has MSHA approved this coal <br />slurry plan? If so, is the MSHA-approved plan different than <br />the plan submitted to our offices? If the plan is different, <br />please revise your DMG submittal to reflect the MSHA plan. If <br />the MSHA-approved plan is the same, please provide whatever <br />approvals MSHA has granted. <br />9. In the May 11, 1994 submittal, it is stated that "the water in <br />the thickener achieves a chemical equilibrium, albeit a <br />changing one, with the water running through the plant." <br />Please explain the reference to a changing equilibrium. <br />10. In the May 11, 1994 submittal, Basin states that "the use of <br />LA 221 A assumes that water quality observed in the Maxwell <br />seam is comparable to water found in the Allen seam at New <br />Elk." Please explain the basis for this assumption. <br />11. On page 2.05-90b of the May 11, 1994 submittal, site NEW-3 is <br />shown as being sampled quarterly for water level and field <br />measurements, whereas sites NEW-1, NEW-2 and NEW-4 are shown <br />as being sampled monthly. Why is NEW-3 not going to be <br />sampled monthly? <br />12. On page 2.05-90f, please add to each description for NEW-1, <br />NEW-2, NEW-3 and NEW-4 that the well is also being used to <br />monitor water quality in the mine workings. <br />13. On page 2.05-90d, please add to the description for NE-006 <br />that pond 6 is no longer a discharging pond and that it no <br />longer is a sedimentation pond. <br />14. The Division is reviewing the following publications from the <br />Water Quality Control Commission and how they pertain to this <br />technical revision: 1) "Colorado Water Quality Control Act", <br />August 1993, 2) "Classifications and Water Quality Standards <br />