MINES AND TUNNELS.

New Zealand Herald, Volume LV, Issue 16796, 12 March 1918, Page 7

MINES AND TUNNELS.

NEW ZEALANDERS' WORK.

GOME SURPRISING DISCOVERIES.

[rnoji oun on"\ correspondent.]

LONDON. Dec. 2S. The following account of the work done by tho New- Zealand Tunnelling Corps for the Fourth Army in preparation for the battle of Arras is furnished by General CJodlcy. Apart from the unique military interest of the work it developed nil archaeological aspect of very great importance : —Tho development of underground shelter for attacking troops to tho extent carried out at Arras by tho 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, naturrally has associated with it fabulous stories of long galleries, leading to and from widely separated monasteries and villages, and used formerly by the old-timo tyrants and well-meaning but retiring churchmen. It was while engaged in a search for such, with the purpose of passing behind the enemy's lines, that a great systom of caves, largely forgotten or wrapped in mysterious 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 onco realised and pointed out by tho company. The suggestion was taken up and the huge enterprise launched of in four and a-half months making six miles of gallery, levelling 15 acres 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 tho grip of the hardest frost known in Europo tor a decade was, by radiator troubles, daily reducing the available transport. Or, should a thaw come, thaw regulations absolutely forbade heavy traffic on tho roads.

Relics of the Spaniards. Their age and artificial origin gives the caves a particular interest. They are really great chalk mines, from which building stone has for ages been obtained for adjacent villages and towns. Their extensive development appears to date from the timo of the Spanish occupation, when building went on briskly. Several carved records of names with dates going back to the sixteenth century were found, also one mouldering felt hat of the shape affected in Armada days. Tho chalk stone is white, resembling the Oamaru Btono 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 froo from flints, is not found tnroughout, and near Arras lies 40ft to 50ft below the surface, hence tho necessity for mining it instead of quarrying in the open. It was mined in much the samo 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. Tho buildings nearly all havo cellars, particularly those in tlio Spanish quarter, where they are well built, largo, and close together. Tho defences were, except in ono part, demolished about 30 years ago, and along tho eastern or enemy side a large sewer was built along the bottom of tho old moat— some distance 60ft below the surface— it was filled in, thus providing a good subway. Tho caves lay outside tho town in tho eastern suburbs, and beyond was " No Man's Land," about 2500 yds from the centre of the town.

The Schemo Outlined. To effect the purpose of providing secure billets for 20,000 troops whilst in waiting, and, later, a safe passage up to the attack, tho 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 the sewer. From the sewer exits were pro. vided to several open communication trenches, and in addition two galleries, 4ft wide, were made to tho front line, one on the right known as Godley Avenue, passing through and connecting tho Ron villo group of caves, called Russell, Auckland, New Plymouth, Wellington, Nelson, Blenheim, Christchureh. Dunedin, Bluff, and that on the left known as King Street, connecting the St. Sativeur group of 10 caves, named after British towns. ' It was intended to mako each of the two main galleries sorvc a front of 1000 yds by forking the ends. This intention was only fully developed on the left, where fivo forks were made, all reaching to within a fow feet of the German lines. On the right a premature withdrawal of the enemy rendered the full realisation of the scheme unnecessary, though the gallery provided a very valuable safe means of communication to the immediate neighbourhood of operations.

The Mines Exploded. Not only were main through ,?alkies constructed, but eacli cave was provided with from two to eight exit? to the surface serving for ventilation and as emergency means of withdrawing troops. Four other isolated caves were similarly dealt with and fitted up as ammunition dumps, with hoisting gear for handling shells in quantity. Another rave was opened up by the miners' unit and fitted by the Royal Medical Corps under the instruction of the medical officer for use as a casualty clearing station. The further work entailed in levelling off cave floors, propping roof, ventilating, fitting gas doors, finding mining timber, ; laying tramways, providing forward dugI out,? off galleries for headquarters, store*.' [ etc., fittinc 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. All participants felt fully compensated for their efforts whon, at the appointed time, the mines were safely blown, the ' galleries opened out, and the infantry, ! fresh lifter a good night's rest, _ passed, I with onlv very slight casualties, into the I Gorman lilies to win a great victory. /