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Page 5 <br />Carol Russell <br />April 8, I98I <br />area of Empire Energy's Eagle Mine Complex. The features in question <br />occur within the area south of the third east entry of the #5 mine] (SE l/4, <br />Sec. 6, T5N, R91W); in the area above and north of the proposed 7N-6R panel <br />of the #5 mine (N 1/2 of Sec. 32, T6N, R91W); in the area east of the <br />first north main of the #9 mine (SW 1/4, Sec. 29, T6N, R9~W); and within <br />the area above and south of the proposed second east main of the #9 mine <br />(N 1/2 of Sec. 29, T6N, R91W). <br />Without surface reconnaissance of these features and correlation with known <br />areas of historic extraction, it is impossible to determine whether or not <br />these anomalous soil moisture concentrations are subsidence artifacts. The <br />applicant should, in accordance with Rules 2.04.3(3), (a)-•(d) and Rule <br />2.I0.3(1)(k), submit appropriate narrative and maps locat:!ng the extent of <br />historic mining within the proposed permit area. A map should suffice <br />indicating the mine names, seams extracted, the extent of the extracted <br />area, approximate dates of extraction and location of suri.'ace entries. The <br />only historical mine data included within the permit documents is a map of <br />the Wise Hill #4 mine workings, map IV-12. <br />If the areas of historic extraction correlate with the obeerved anomalous <br />soil moisture occurrences, the applicant should discuss tt~e implications of <br />the indicated subsidence for the subsidence projections oi` the Eagle Mine <br />Complex. <br />The final paragraph of this document section hypothesizes that no material <br />damage has occurred to aquifers as a result of previous sL~bsidence occurrences. <br />The narrative refers, as an example, to monitoring well #210 shown on map <br />IV-I3, which is located down dip from the -northern limits of the Wise Hill <br />#4. The statement is made that artesian flow issues from approximately 85 ft. <br />below the surface and that this occurrence indicates that the mine roof caving <br />experienced within the Wise Nill #4 has not significantly affected the <br />overlying aquifer system. This brief statement is not sufficient to support <br />that opinion. The narrative should be expanded to discuss the stratigraphic <br />positions of the well and the mine workings. Further, a discussion of the <br />hydraulics of the well should be included to demonstrate that disruption of <br />the aquifer by collapse of the mine workings would necessarily have eliminated <br />artesian flow within the. well. If the workings are flooded, the affects upon <br />the piezometric head of the well might not be sufficient to eliminate artesian <br />flow. The applicant should clarify and support the conclusion that continued <br />flow from Well 210 necessarily demonstrates that the caving experienced in <br />the Wise Hill #4 mine has not had a significant affect upon the overlying <br />aquifer system. <br />4.6.3 Description of Worst Possible Consequences of Subsidence if it <br />Occurred on Structures or Renewable Resource Lands. <br />4.6.3.3 Description of Worst Possible Consequences <br />The statement is made by the applicant (page iV-113); "Also as extraction <br />increases, the potential for surface effects increases. However, this <br />(con t' d ) <br />