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Dual containment facilities should include, at a minimum: <br />(1) the production well field drainage pond <br />(2) all well field pipelines <br />(3) storage, processing or fluid transmission facilities within, leading to or from the <br />processing plant, <br />(4) all evaporation ponds <br />(5) all return flow lines from evaporation ponds and <br />(6) all other storage, processing, or conveyance structures that contain or transmit <br />processing fluids. <br />6. The well field test facility should be thoroughly mapped prior to drilling to assure as much <br />as can be inferred from surface geologic mapping that wells will not intersect faults and <br />thereby permit potential cross - contamination of aquifers. <br />7. Composition of the process solutions should be geochemically characterized as pilot testing <br />proceeds. Differences in fluid composition at various temperatures, if significant, should <br />be reported to the Division. <br />8. Section D -3.2 and diagrams. Success of the proposed mining method depends, in part, on <br />self containment of fluids in each production well. If fluids from one well cavity reach an <br />adjacent cavity, the model parameters of subsidence would not be valid. The operator <br />should explain how solution migration will be monitored in situ, and how cross - cavity <br />connections will be controlled. The concern is that the more continuous, nahcolite rich <br />beds such as the Greeno, Love and TI will dissolve out much farther from the well stem <br />than the subsidence models predict, and that there is not proposed monitoring method to <br />warn if that is happening. <br />• • <br />SPECIFIC COMMENTS <br />1. A typical pond liner design (Figure C -8; double -liner with leak detection; also page D -33 <br />Section E) for storage of process solutions and waste streams is provided. The narrative <br />indicates there will be a combination leak detection and collection system between the <br />liners. However, leak detection/collection specifications are not shown on the diagrams, <br />and there appears to be no provision for leak collection on the diagrams. <br />2. Based on USGS and other groundwater information, it would appear to the Division that <br />the process solutions may be similar in composition to water in the dissolution zone, which <br />are close to saturation with respect to several elements. As such, the waters if ingested <br />should be toxic to a variety of animals. For this reason, it is anticipated that all open ponds <br />that contain either process solutions or waste streams should be protected from wildlife <br />intrusion through fencing and covers such as netting. <br />3. Based on well casing specifications shown in figure D -3.3 ( "Production Well, Proposed <br />Well Completion Diagram ") it appears that waters in the shallow Uinta Formation may <br />come in contact with deeper waters of the Dissolution Zone. In other parts of the Piceance <br />Basin, the Uinta provides potable water whereas the dissolution surface does not. <br />Moreover, in parts of the basin, groundwater gradients are vertical and upward. The <br />operator should indicate how waters from the deeper more saline formation will be <br />prevented from co- mingling with those in the Uinta. <br />2 <br />