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West Elk Mine <br />• Gulch area, west of the 7NW longwall panel. In this area, the minimum 300 feet of B Seam <br />overburden provides little buffer between the combined caved/fractured zone height and the known <br />springs. Detailed monitoring of this area during mining will allow MCC to assess potential impacts <br />to well springs in the upper fractured zone and to support or refine predicted effects. <br />There is a higher probability that colluvial and alluvial springs will be impacted by surface cracks, <br />although this risk is also quite small, for the many reasons that are presented in Section 2.05.6 <br />(3)(b)(iii & viii) Surface Water Quantity Effects, Streams. Consider the following factors: <br />It is not feasible to quantify the probability that a spring will encounter a surface crack. <br />However, as with stream channels and stock ponds, the probability that a spring in the raining <br />area will encounter a crack is quite small. <br />2. Spring flows that enter a crack will continue to move downgradient, leading to spring relocation <br />rather than spring loss. <br />3. Cracks that do occur are likely to be found in association with chain and barrier pillars. The <br />evidence from the northwest longwall panels 1 through 8 and experience elsewhere, indicates <br />the probability of cracking within the internal portions of the panels is much lower. This will <br />facilitate crack monitoring and mitigation. <br />4. In the unlikely event that cracks do develop within the internal portions of the panels, there are <br />• various "healing" mechanisms, which will act to fill in the crack within a few months. <br />5. Although surface cracks located over the pillars are less likely to "heal" themselves, they will fill <br />in over time via "sealing" mechanisms, principally in the form of sediment inflows. <br />6. Most spring flows which infiltrate into surface cracks will re-emerge dowvngradient; <br />consequently, the water will not be "lost" to the basin, which is important from a water rights <br />standpoint. <br />In short, it is very unlikely that the recharge source for any given alluvial/colluvial spring or spring <br />itself will encounter a surface crack. If this does happen, however, the ameliorating factors listed <br />above will apply. <br /> <br />7.05_203 Revised June 2005 PR10; Rev. Mach 2006; Rev. May 2006 PRIO; Sep. 2007 PR12; Feb 2008 PR12