Complex sentence: In 1918 a major breach caused by mining subsidence caused the last few miles of the canal near Ashby to be abandoned, the canal was nearly closed completely, only the strategic importance of the coal supplies during the First World War allowed it to survive.
Split into simpler sentences: In 1918 a major breach caused by mining subsidence caused the last few miles of the canal near Ashby to be abandoned. The canal was nearly closed completely, only the strategic importance of the coal supplies during the First World War allowing it to survive.