2008-03-03_PERMIT FILE - C2006085 (16)

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Ms. Angela Bellantoni Apri125, 2007 Page 7 • Monitoring Program Northfield has had a monitoring program in place since 2005 to collect baseline data. The monitoring data and the monitoring program will provide an early warning system so that concerns can be mitigated before they become problematic. Hydrographs from the water level monitoring wells are presented in Appendix 6. The monitoring data indicate that water levels have not changed significantly in recent months. We note that the water levels in NF-O1 and NF-03 took a long time (approximately six months) to reach an equilibrium water level, which is indicative of very low permeability of the formation material. The monitoring program can be expanded to include additional wells, including production wells. As indicated above, it is our recommendation that key wells are identified and included in the monitoring program to insure that they are not adversely impacted by mining activities, and to provide an early warning system in the unlikely event that adverse impacts do occur. If the wells are included in the monitoring program we recommend that water levels are measured in the wells on a periodic basis and that the efficiency of the wells is also measured on a periodic basis by completing pumping tests on the wells. 1~ S ~t-e_ -eve c~-..~ ~J vv c~-J~ZZ~k., Mitigation Plan • Northfield Partners has developed a mitigation plan to address problems related to hydrology and water supply wells, should problems arise. The mitigation plan is structured in tiers, as follows: uJ ~ ~ ~ 0 " S ~ ma~~ ~ ~~ 1. Tier 1: Water level monitoring plan 7 a. The water level monitoring program will provide an early warning system ~~ ~'` should water level changes occur from mining 2. Tier 2: Mitigation utilizing existing well structures a. Lower pump setting depths in wells b. Well rehabilitation (improve the efficiency of well through cleaning , if needed and appropriate) c. Modifications to existing well production intervals (grout intervals near coal) 3. Tier 3: Mitigation involving alternative water supplies a. Construct new wells in different production intervals removed from coal b. Haul water to cisterns at home sites This mitigation plan will further insure that should problems with wells arise, they will be addressed by Northfield Partners. Northfield has communicated to the County and the DRMS that they are committed to being a good neighbor to nearby property owners, and should problems with wells arise, Northfield will provide mitigation.