WORK OF OUR TUNNELLERS. SOME SURPRISING DISCOVERIES. (PROM OVB. OWN CORRESPONDENT.) LONDON, 28th December.
Lieutenant-General Sir A. J. Godley furnishes me with the following interesting account of tho work done by the N.Z.T.C. for the Fourth Army in preparation for the battle of Arras. A part from the unique military interest of tho work it developed an archaeological aspect of very great importance:-
"The development of underground shelter for attacking troops," says the narrative, "to the extent carried out at Arras in 1917 by the New Zealand Tunnelling Company was, it is believed, unique in military history."
"A land like Northern France, which has so frequently been the scene of battle, naturally has associated with it fabulous stories of long galleries, leading to and from widely-separated monasteries and villages, and used formerly by old-time tyrants and well-meaning but retiring churchmen.
"It was whilst engaged in a search for such, with the purpose of passing behind the enemy's lines, that a great system of caves, largely forgotten or wrapped in mysterious grandfathers' tales was discovered. Their value for sheltering attacking troops, where all available roads and billets were under fire, and peculiarly susceptible to interference from enemy barrage, was at once realised and pointed out by the company. The suggestion was taken up, and the huge enterprise launched off in four and a half months, making six miles of gallery (1,100 yards more than Arthur's Pass Tunnel, New Zealand), leveling 15 acre of cave, laying goods tramways throughout and lighting up the whole with electricity; this, too at a time when not only were supplies difficult to obtain, but when either the grip of the hardest frost known in Europe for a decade was, by radiator troubles, daily reducing the available transport. Or, should a thaw come, thaw regulations absolutely forbade heavy traffic on the roads.
"Their age and artificial origin give the caves a particular interest. They are really great chalk mines, from which building-stone has for ages been obtained for building adjacent villages and towns. Their extensive development appears to date from the time of the Spanish occupation, when building went on briskly. Several carved records of names and dates, going back to the 16th century, were found, also one mouldering, felt hat of the shape' affected in Armada days. The chalk stone is white, resembling the Oamaru stone of New Zealand, only finer and denser in structure, and capable of being more finely carved. Though there is a great thickness of chalk, building quality stone, which must be solid and comparatively free from flints, is not found throughout, and near Arras lies 40ft to 50ft below the surface, hence the necessity for mining it instead of quarrying in the open. It was mined in much the same manner as a coal seam, pillars of stone being left to support the ground overhead. Noteworthy is the fact that a better quality of chalk was sought, and used, in the old, than in later days.
"Arras is a more or less circular city about a mile across, and was once defended with, a continuous encircling wall and moat. The buildings nearly all have cellars, particularly those in the Spanish quarter, where they are well built, large, and close together. The defences were, except in one part, demolished about 30 years ago, and along the eastern or enemy side a large sewer was built along the bottom of the old moat (for some distance, 60ft below the surface) before it was filled in, thus providing a good subway. The caves lay outside the town in the eastern suburbs, and beyond was. 'No Man's Land'— about 2,600 yards from the centre of the town.
"To effect the purpose of providing secure billets for 20,000 troops whilst in waiting, and, later, a safe passage up to the attack, the cellars in the old Spanish quarter, that is the north-eastern quadrant of the town,' were all connected together, and, also, at three points to tho sewer. From the sewer exits were provided to several open communication trenches, and in addition two 4ft wide galleries were made to the front line, one on the right, known as Godley Avenue, passing through and connecting the Ronville group of caves, called Russell, Auckland, New Plymouth, Wellington, Nelson, Blenheim, Christchurch, Dunedin, Bluff, and that on the left known as King-street, connecting the St. Sauveur group of ten caves named after British towns.
"It was intended to make each of the two main galleries serve a front of 1,030 yards by forking the ends. This intention was only fully developed on the left where five forks were made, all reaching to within a few feet of the German lines. On the right a premature withdrawal of the enemy, rendered the full realisation of the scheme impassible, though the gallery provided a very valuable safe means of communication to the immediate neighbourhood of operations. "Not only were main through galleries constructed, but each cave was provided with from two to eight exits to the surface, serving for ventilation and as emergency means of withdrawing troops. Four other isolated caves were similarly dealt with and fitted up with ammunition dumps, with hoisting gear for handling shells in quantity. Another cave was opened up by the unit's miners and fitted by R.A.M.C., under the instruction of the unit's medical officer, for use as a casualty clearing station.
"The further work entailed leveling off cave floors, propping roof, ventilating, fitting gas doors, finding mining timber, laying tramways, providing forward dugouts off galleries for headquarters, stores, etc., fitting up electric power plant, and wiring all galleries and caves was prodigious, and British Generals were very free in their praise of colonial capacity for sustained effort, organisation, and for accomplishing the apparently impossible, and feats of work.
"All participants felt fully compensated for their efforts when, at the appointed time, the mines' were safely blown, the galleries opened out and the infantry, fresh after a good night's rest passed with only very slight casualties, into the German lines, to win a great victory."