Original sentence: The Big Hill mine in Lucas worked a 4-foot thick coal seam 290 feet below the surface, with a shaft not far from the Burlington station.This mine was closed in 1907 because of water problems
Edited sentence: The Big Hill mine in Lucas worked a 4-foot thick coal seam 274 feet below the surface using room and pillar methods, with a shaft not far from the Burlington station.The problem was, the rock directly above the coal was sandstone and it was saturated with water.The reopening lasted until 1907, when the mine was closed again.This mine was closed in April 1904 and stripped of equipment, but by mid 1905, plans were in place to reopen it