Complex sentence: The Kasino Point mine was late and several casualties were suffered by the nearest battalion but the three brigades advanced from repaired trenches and taped lines rather than from newly dug jumping-off trenches, which were considered to advertise the imminence of an attack.
Split into simpler sentences: The Kasino Point mine was late and several casualties were suffered by the nearest battalion. The three brigades advanced from repaired trenches and taped lines rather than from newly dug jumping-off trenches, to avoid advertising the imminence of an attack.