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Hvdroloev The Lone Pine Gulch B-Seam portals aze at an elevation of approximately 6,480 feet compared to the F-Seam Portals at the West Elk Mine site situated at approximately 6,473 feet. Due to the dip of the coal seam, the entire abandoned azea water (which includes Northwest Longwell Panels (Nos.l-7); the Jumbo Mountain Longwell Panels (Nos. 8 and 9), and Longwell Panels (Nos. 12, 13, 13A)] could eventually flow to this portal azea. The worst-case scenario would show water accumulating behind the seals and bulkheads at the Lone Pine Portals. If the water accumulates against the seals and bulkheads it could create the potential for high static head pressure and create the potential risk of bulkhead failure. However, due to shallow surface cracking known to occur in the out-crop area and the fact that the Northwest Panel Sump is drained of water via piping (apass-through) from the No 1. Northwest Longwell Panel to Panels Nos. 10 and 11 sump (Northeast sealed sump), it is not expected that water would build-up or accumulate behind the Lone Pine Portal bulkheads. Designs for the bulkheads have incorporated this worst-case scenario. If, for any reason, the pass-through piping becomes blocked, the water in the Northwest Panels could accumulate at the Lone Pine Gulch Portal seals and bulkheads and then flow to the Box Canyon Mains. The sump descriptions and operation aze included in the approved mining and reclamation permit at pages 2.05-237 through 2.05- 248. The bulkheads are designed as watertight barriers capable of withstanding 130 feet (or 56 psi) of head pressure. Additionally, placement of backfill material against the outside of the bulkheads will increase the strength of the bulkhead and the forces it can withstand. As was previously stated, the water could accumulate behind the Lone Pine Portal bulkheads. Water would accumulate to the point of overflowing at the No. 6 Entry of the B-West Mains at an elevation of 6,557 feet. If the elevation of the Portals (6,480 feet) is subtracted from the elevation at No. 6 Entry of the B-West Mains (6,557 feet) the head pressure exerted on the Lone Pine Portal bulkheads is 77 feet or 33 psi. The water, upon reaching No. 6 Entry, would then flow to the Longwell Panels Nos. 10 and 11 sump. From this sump the water is pumped from the mine via the Mine De-Watering Borehole Facility in Sylvester Gulch. If water were to fill the Nos. 10 and 11 Panel Sump the water would flow to the down-dip active workings in the Box Canyon Mains. It is not expected that water would exit the F-Seam Portals because the top ofthe F-Seam Slope entries are at an average elevation of 6,856 feet. The post-mining dewatering will be addressed in the future when mine closure is anticipated. This issue was addressed in the Box Canyon Panels Sealed Sump in the approved mining and reclamation permit at page 2.05-242. Drawin¢s Attached aze the general arrangement, plan view, and profile of the bulkheads.