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• • Hydrologic Data /nferpremrion and /mpacf Assesnnenr for the Pcnnif and Adjacent Areas After the panel was retreat mined, a small wet area developed on the Boor in the 1st Wesl Submain adjacent to the panel. However, pumping was unnecessary and the wet area dried up. During 1990, no in-mine Bows were observed in this area. Panel 1 W6S Mining of this panel began during 1989. Panel 1W6S is under an average oC 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 off the 1st West Submain. Hydrologic conditions in this panel were similar to the other panels off the 1st Wes[ Submain. The panel was mostly dry. Howev- er, a few 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. Panel 1 W1 N This panel was developed and partially retreat mined during 1990. The panel consisted of 12 crosscuts. Roof and overburden conditions over the last five crosscuts in this panel were not favorable Cor extensive mining. Overburden thickness ranges from 500 feet to 800 feet. In addition, a drainage overlays these five crosscuts. Thus, the roof in this area was highly fractured and unstable. Because retreat mining could not safely occur under these conditions, the pillars were left in place. Although water was present in the panel during mining, it was very limited. Roof drippers were present in the last five crosscuts Cor the first month after development. Thereafter, the roof remained damp. Panel 2W1 N This panel was developed and completely retreat mined during 1990. The panel consisted of 18 crosscuts driven west off of Panel 1W1N. Roo(and overburden conditions over most of this panel were similar to those in Panel IW1N. Over- burden thickness ranges from 200 Ceet to 750 feet. In addition, a drainage overlays most of this panel. [n particular, the roof over crosscuu one through 12 was highly fractured and unstable. Because the entire panel could not be retreat mined safely, same pillars were left in place. At one point, a root fall buried a ramcar. This ramcar was parked and unoccupied at the time of the fall. However, all attempts to safely recover the equipment failed and the ramcar was left buried. Limited water was present in this panel. During development, root drippers appeared in the south half o(the crosscuts. This area continued to be wet through retreat mining. However, at no time was Bow from these drippers measurable. 1st East Submain The 1st East Submains were retreat mined and scaled during the Brst half of 1989. Poor roof conditions (fractures, water, and weak rock materi- al) were the major reasons for retreat mining this Submain section. Although increased Bows may occur Following subsidence, they are not expected to be significant. No Bows 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 fracture zones associated with the branches of Sylvester Gulch. However, due to ongoing development of the "B" scam, this Sub- main is unlikely to be driven for several years. Northwest Submains WECC began developing the Northwest Submains during 1990. These Submains strike out from the Southwest Main Intakes (Exhibit Ill). Develop- ment progressed to crosscut 12 before loose roof conditions precluded (unhcr advancement. WECC now plans to continue Submain development to the northwest through the 2 Northwest Submain off Panel NW1S (Exhibit III). ]0