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• • Hydrologic Gera hunpemion and bnpau A.vemnw fa the Pomir mid Adjacent Azar 750 feet at the southern panel end). Coal height also thins to the west Mining conditions were similar to those in panel 1 W4S. Roof drippers and wet areas oavrreA, but no significant inflows were encountered. Panel 2W1N This panel was developed and completely retreat mined during 1990. The panel consisted of 18 crosscuts driven west off of Panel 1W1N. After the panel was retreat mined, a small wet area developed on the floor in the 1st West Submain adjacent to the panel. However, pumping was unnecessary and the wet area dried up. During 1991, no in-mine flows were observed in this area Panel 1 W6S Mining o[ this panel began during 1989. Panel 1W6S is under an average of about 350 feet of overburden. Due to the trend of decreasing cover and thinning coal with westward expansion, this panel was the last panel to the west driven oft the 1st West Submain. Hydrologic conditions in this panel were similar to the other panels otf the ist West Submain. The panel was mostly dry. Howev- er, afew very small localized damp roof areas or roof drips have occurred. Panel 1W6S was completely retreat mined during 1990. No new wet areas were encountered during retreat mining. No in-mine flows were observed during 1991. Panel 1W1N This panel was developed and retreat mined during 1990. The panel consisted of 12 crosscuu. Roof and overburden conditions over the last five crosscuu in this panel were not [avorable for extensive mining. Overburden thickness ranges from 500 feet to 800 feet In addition, a drainage overlays these five crosscuu. Thus, the roof in this area was highly fracured and unstable Becatuc retreat mining could not safely occur under these conditions, the pillars were left in place. Although water was present in the pane] during mining, it was very limited. Roof drippets were present in the las[ five crosscuts for the fast month after development. Thereafter, the roof remained damp. No in-mine flows were observed from this pane] during 1991. Roof and overburden conditions over most of this panel were similar to those in Panel 1W1N. Over- i , burden thickness ranges from 200 feet to 750 feet , , U addition, a drainage overlays most of this panel. In particular, the root over crosscuu one through ~ 12 was highly fractured and unstable. Because the entire panel could not be retreat mined safely, some pillars were left in place. At one point, a roof fall buried a ramcar. This ramcar was parked and unoccupied at the time of the fall. However, all attempu to safely recover the equipment failed and the ramcar was left buried. Limited water was present in this panel. During development, roof drippers appeared in the south half of the crosscuu. This area continued to be wet through retreat mining. However, at no time was flow from these drippers measurable. No in-mine flows were observed during water year 1991. 1st East Submain The 1st Fast Submain was retreat mined and sealed during the first halt of 1989. Poor roof conditions (fractures, water, and weak rock materi- al) were the major reasons for retreat mining this submain section. Although increased flows may occur following subsidence, they are not expected to be significant. No flows have developed to date. An alternative access submain to coal in the eastern portion of Federal lease C-1362 is planned. Placement of this submain would be further to the south under higher overburden and further from the 6aaure zones associated with the branches of Sylvester Gulch. However, due to ongoing development of the "B" seam, this sub- main is unlikety to be driven for several years. 1 Northwest Submain MCC began developing the 1 Northwest Submain during 1990. This submain strikes out from the • ]0