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• 5.0 Ground Water Information The data collected from Oxbow's groundwater monitoring sites, along with the results of laboratory analyses are presented in Exhibit 2 -Groundwater Information. The following site discussions are presented from west to east through the OMLLC property. H-10 Well - B-Seam -Somerset Mine Workings - Hubbazd Creek Drainage •:~~r~as~~-tier ~ ~ .:; -u .,.x ~ _ The sealing o`'all~of tie' abandone'Somerset IVlihe portals`has precluded access into the mine to obtain underground mine water samples from those abandoned workings. Instead, since the Somerset mine was closed in 1985, monitoring wells H-10 and B-6 have been utilized to monitor potential groundwater inflow and quality in order to predict the extent of flooding in the abandoned underground workings. Monitoring water levels in these two wells serves as a valuable predictive tool as to whether water from flooded mine workings could impact the hydrologic balance. The H-10 well is located in Hubbard canyon near the western limit of underground B seam mining of the Somerset mine and neaz the north or down-gradient limit of the old mine workings in that specific area. The elevation of the B seam in the well is ~ 6010 feet. From 1987 to 1989, the water level in H-10 held steady at about elevation 6028 feet, and then in 1992 rose to approximately 6068 feat in elevation. From 1989 until 1999, the water level ranged from 6067 • feet to 6069 feet in elevation. In October1999 and 2000 through 2004 no water could be measured in the well. This lack of water in the well suggests that there is no longer a significant inflow into the abandoned mine workings in this vicinity. The Somerset mine workings in this vicinity appear to behaving no impact to the local hydrologic balance. B-6 Well - B Seam -Somerset Mine Workings -Bear Creek Drainage The B-6 well is also located in adown-gradient location in the abandoned Somerset Mine workings in the vicinity of Bear Creek canyon. The elevation of B seam in this vicinity is -5925 feet. In monitoring the B-6 well, the historical fluctuation of water levels has been different than experienced in well H-10. After initially rising to elevation 6035 feet, the water level fell to elevation 6014 feet in 1990. Water levels then recovered, with a increase to elevation 6033 feet in 1992, and rising to elevation 6051 feet in 1993. The water level ranged from 6038 feet to 6048 feet in 1994 and 1995, and then rose to elevation 6054 feet in 1997. In 1998 the water level ranged between 6052 and 6053 feet in elevation. Similar to monitoring well H-10, since October 1999 and during 2000 through 2004 no water was measured in well B-6. • The lack of water in the H-10 and B-6 wells maybe due to a blockage or another problem in the wells. The scenario that both wells failed at the same time appears, however, unlikely. 10