Laserfiche WebLink
In the 1983 Findings for the Foidel Creek Mine, the Division concluded that lower Foidel <br />Creek, lower Middle Creek and lower Trout Creek were alluvial valley floors because of a <br />presumed capability to support flood irrigated and subirrigated agricultural activities. The <br />Trout Creek AVF was addressed previously in this section. Subimgated alluvium on Middle <br />Creek downstream of Routt County Road No. 27 crossing does not meet AVF criteria due to <br />limited farrnable acreage, as was also discussed previously. <br />The alluvial body at the confluence of Foidel Creek and Middle Creek extending from the <br />County Road No. 33 crossing of Middle Creek upstream on Middle to the first Trout Creek <br />irrigation diversion as depicted on Map No. 15, Water Rights and Alluvial Valley Floors, <br />does meet alluvial valley floor criteria based upon existing flood imgation and a presumed <br />capability to support subirrigated vegetation. These findings do not address areas further <br />upstream on Middle Creek, as they are not hydrologically connected to the proposed mining <br />operation. The required findings for the identified alluvial valley floor at the confluence of <br />Foidel Creek and Middle Creek are set forth below. <br />The proposed mining operations would not interrupt, discontinue or preclude fanning on <br />the alluvial valley floor. <br />The mine plan for the Eastern Mining District was shortened from the originally proposed <br />panel length for longwall panels 9R and 8R. Longwall panels in the Eastern Mining District <br />did not undermine the Foidel Creek/Middle Creek Confluence AVF. Proposed longwall <br />panels 6R through 2R in Eastern Mining District presented in PR-04 undermined a portion of <br />Middle Creek; however, the affected portion of Middle Creek is not designated as an AVF. <br />The proposed mining operations would not cause material damage to the quantity or <br />quality of surface and ground water that supply the alluvial valley floor. <br />As discussed in the PHC Section of this document, significant dewatering of the Foidel Creek <br />or Middle Creek stream alluvial systems due to undermining would be precluded by the low <br />vertical permeabilities between the Wadge seam and the alluvia. Stream flow loss to surficial <br />tensional cracks which may develop is expected to be minimal and the fine-grained nature of <br />the alluvium will rapidly fill any cracks that may develop. Furthermore, surface cracking due <br />to subsidence is typically limited to a maximum of 50 feet in depth and direct connection to <br />the workings is not anticipated due to overburden depths in this azea in excess of 600 feet. <br />Also, any stream flow loss will be more than compensated by the projected and existing mine <br />dischazge to Foidel Creek averaging over 600 gpm. And lastly, the entire alluvial valley floor <br />is flood irrigated by water diverted from the unaffected segment of Trout Creek above its <br />confluence with Middle Creek, nullifying any temporary, minor impacts which could occur. <br />(See TCC Life of Mine Application Map No. 15). <br />The primary function of the confluence AVF is the support of flood imgated hayland. As <br />previously noted, the flood irrigation water is not diverted from affected segments of either <br />Foidel Creek or Middle Creek, but is diverted from an unaffected segment of Trout Creek. A <br />field inspection conducted by the Division in late August of 1986 observed vegetation on the <br />flood irrigated AVF to be more robust than adjacent areas upstream on Foidel Creek above <br />38 <br />