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• Other than one unusually high pH reading of 9.91 in Well 29-4 in December of 1988, no problems with pH are evident. The 12188 sample at Well 29-4 occurred before any ground was disturbed and could not be the result of any activities of Rimrock Coal Company. All samples show pH levels between 7.0 and 8.5, which are within acceptable pH limits. Conclusions As is seen from the pre-mine water analysis, the water available from the Vermejo Formation around the permit area is alkaline and very salty, which restricts its use for human consumption, however, it can be used for livestock. The lower part of the Vermejo Formation, where the Rimrock disturbance occurred, cannot he considered a significant source of water in the permit area. As is seen in the maps of the existing permit, the Engleville Mine workings almost completely surround the Rimrock pit except for the north part of the permit area itself, where the Starkville seam outcrops although it is covered by talus. These workings disturbed the same seam (Starkville) that was mined by the Rimrock pit. If the dip of the workings vas such that groundwater entering the old mine workings backed up in the dead end entries, the • Rimrock excavation could have provided an easy outlet for this water, but all tunnels encountered were dry in the 1300 feet of pit excavation. Since these underground workings cover a few square miles in the area, it is virtually impossible that the Rimrock excavation could affect the groundwater flow in the Vermejo of the immediate area. It had already been affected many years ago by the Engleville Mine. It is possible that recharge rates in the excavated area could increase slightly after reclamation, due to the breakup of the laminated strata of the Vermejo in the excavated area. This affect would not be significant if it did occur and it would also not be detrimental. Well level sampling does not support any significant changes. On the east side of Engleville Gulch in the permit area, the Engleville Mine does discharge water through a pipe from one of the workings to Engleville Gulch. The land east of Engleville Gulch has not been affected by Rimrock mining and, since all Rimrock excavation was above stream level, the east side of the Gulch could not be hydrologically affected by the recent mining. The Trinidad Sandstone, recognized as a minor regional aquifer, was not affected by mining since it underlies the Vermejo Formation. • ? 07(1) Page l 3 1/12/95 -,~':