Fine morning. Showers later. Enemy arty very quiet. Mining Offr. reports Germans working on gallery in front of “A” Coy, so decide to blow him. Miners commence work for blow at 9.0 pm. Working very hard , blow to take place at 2.0 am. Orders given for all ranks to stand to. Mine exploded 2.4 am 28/29 inst. Big shock & much larger crater than expected. Fine sight large cloud smoke, enemy very nervous plenty of Very lights, rifle & Mgunfire. No shelling. Part of our parapet in 39 Trench blown in, 4 Lewis Gunners buried, no wounds shock only. All quiet by 3.30 am. Turned in 3.0 am.