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1987 PRODUCTION AND GEOLOGIC CONDITIONS Page -2- • Anomalous conditions: The strata was burned, oxydized, and weathered in the 1 Left portal area. South III Submains Mined length: Submain type development was advanced relatively north for approximately 4,000 ft. Overburden thickness: 450 - 650 ft. Mining height: B.0 - 9.5 ft. Roof: The initial development encountered roof the same as in the First West Submains. These conditions changed including an increase in fractures, slickenslides, differential compaction zones and some separations due to sag. The siltstone material was increasingly appearing as mud stone, much softer and subsequently less compe- tent. Various roof falls were experienced as the development pro- ceeded. Minor water seepage in conjunction with the less compe- tent roof material led to these roof falls. These conditions be- came so dominate that economical mining could not be achieved. The area was abandoned and development of the Second West Submains . commenced. Ribs: Little rib sloughage was encountered. Floor: Same floor as the First West Submains. The interburden varied from 12 - 18 inches thick. Anomalous conditions: The roof falls experienced were a major problem. The major falls consisted of thicknesses up to 8 ft. Falls of 2 - 4 ft. were n~nnerous. Second West Submains Mined length: Submain type development was advanced east for approxi- mately 4,500 ft. Overburden thickness: 200 - 700 ft. Mining height: 9 - 11 ft. Roof: Roof material remained similar to the First West Submains with a minor increase in mud stones, fractures, and slickenslides. Roof falls were experienced sporadically, consisting of thicknesses of • 1 - 3 ft. Two major falls, 6 - 8 ft, thick, were also experi- enced. However, development was not significantly altered. As a solution [o prevent hindering roof conditions, 3 - 4 ft. of top coal was left for additional support. This was possible since the "D" seam interburden diminished entirely. The top coal worked well.