2018-08-10_GENERAL DOCUMENTS - C1982056

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The alluvial body at the confluence of Foidel Creek and Middle Creek, extending from the County Road No. 33 crossing of Middle Creek upstream on Middle Creek to the first Trout Creek irrigation diversion as depicted on Map No. 15, Water Rights and Alluvial Valley Floors, does meet alluvial valley floor criteria based upon existing flood irrigation and a presumed capability to support subirrigated vegetation. These findings do not address areas further upstream on Middle Creek, as they are not hydrologically connected to the proposed mining operation. The required findings for the identified alluvial valley floor at the confluence of Foidel Creek and Middle Creek are set forth below. 1. The proposed mining operations will not interrupt, discontinue or preclude farming on the alluvial valley floor. The mine plan for the Eastern Mining District was shortened from the originally proposed panel length for longwall panels 9R and 8R. Longwall panels in the Eastern Mining District did not undermine the Foidel Creek/Middle Creek Confluence AVF. Proposed longwall panels 6R through 2R in Eastern Mining District presented in PR - 04, undermined a portion of Middle Creek; however, the affected portion of Middle Creek is not designated as an AVF. A small section of Foidel Creek above the confluence of Middle Creek will be undermined with the 5 RT gateroad in the WCR. A very small increase in surface area of Foidel Creek and no surface area increase in Middle Creek is predicted resulting from mining in the WCR. A potential increase in subirrigation may increase productivity in the upland areas surrounding Foidel Creek. The potential for fissures development and water loss (stream pirating) is very low. The AVF will be monitored in accordance with the plan included in Exhibit 4E- 11 of the permit. 2. The proposed mining operations will not cause material damage to the quantity or quality of surface and ground water that supply the alluvial valley floor. As discussed in the PHC Section of this document, significant dewatering of the Foidel Creek or Middle Creek stream/alluvial systems due to undermining would be precluded by the low vertical permeabilities between the Wadge seam and the alluvia. Stream flow loss to surficial tensional cracks which may develop is expected to be minimal and the fine-grained nature of the alluvium will rapidly fill any cracks that may develop. Furthermore, surface cracking due to subsidence is typically limited to a maximum of 50 feet in depth and direct connection to the workings is not anticipated due to overburden depths in this area in excess of 600 feet. Also, any stream flow loss will be more than compensated by the projected and existing mine discharge to Foidel Creek averaging over 600 gpm. And lastly, the entire Foidel Creek/Middle Creek Confluence alluvial valley floor is flood irrigated by water diverted from the unaffected segment of Trout Creek above its confluence with Middle Creek, nullifying any temporary, minor impacts which could occur. (See TC Life of Mine Application Map No. 15). The primary function of the Foidel Creek/Middle Creek Confluence AVF is the support of flood irrigated hayland. As previously noted, the flood irrigation water is Foidel Creek Mine 47 August 10, 2018