Every Aussie’s got a soft spot for Wombats!
Article via Sue Baker Wilson QSM
Project Manager, New Zealand Engineers Tunnelling Company, Waihi Heritage Vision
Kiwi Tunnellers in France used Wombat drilling machines as part of their mining operations. In the Australian Tunnelling Corps, Captain Stanley Hunter was the drilling expert and the inventor of a drilling machine called the ‘Wombat’. The Corps took 36 of these with it and the NZ Tunnellers would also use the machine to their advantage. The Wombat would play an important part in the underground opening scenes of the Battle of Arras. (More on Kiwi Tunnellers at end of post)
The Wombat was named after the Australian animal, said to be the fastest borer known. The Calyx cutter attachment of the drill was made of hard steel. In a 1919 NZ newspaper article on the use of the borer at Messines, the Wombat was reported to be ‘eminently suited to boring in the chalk and flints of the country and did wonderful work.’
It was reported that at Messines the value of the Wombat was in its great adaptability to conditions. It could be used for a straight-down bore, or for horizontal drilling, and was effective in all directions, except boring round corners — it would not do just as it was asked to when an angle had to be negotiated. The special value of the Wombat was in drilling horizontal holes into near-by enemy trenches — 100ft or more away.
The 6in hole was drilled from the Allied trench, the power being men on the handles of the driller. When the hole was far enough, the ammonal cartridges were inserted and pushed very carefully with the drill into the end of the bore, each cartridge being pushed up so that it fitted into the end of the preceding one making a chain of high explosive. No tamping was necessary. Owing to the explosion being instantaneous with the firing of the charge, the air in the bore supplied the resistance needed, and the effect of the blast was all that was desired. A big charge of ammonal, under these conditions, would blow out an open cut of 20ft wide and 14ft deep, and all that had occupied the space previous to the explosion would have been distributed upward and cross-wise. Where an enemy trench was, there was the open cut —unoccupied.
In early October 1916, while still working on underground defences at Chantecler, the NZ Tunnellers proposed to get near enemy lines and blow a communication trench using a tube of ammonal exploded in a hole by a Wombat Borer. Lieutenant McMeeking and a party of eight men were duly despatched for a course of training in use of the Wombat drill at the 1st Army Mining School. On the 19 October, the Tunnelling Company War Diary records McMeeking and his boring team had returned, having also broken all records.
On 6 November the War Diary reports, ‘Trying Wombat borer in J sector – too hard for great success.’ Shortly afterwards the Tunnellers started work on connecting the underground quarries. Here they would use the Wombat again, this time more successfully.
On 18 February 1917 the War Diary records; ‘An experimental wombat chamber, made and started boring a 6in hole today.’ The next day it was recorded that a wombat hole had been bored 70 feet from the experimental chamber. A couple of days later the wombat hole was charged and blown with good results.
Closer to the opening of the Battle of Arras, the War Diary records further use of the Wombat and its part in the Battle of Arras opening proceedings.
22/3/17 Top of Wombat Chamber ran into bottom of a shell-hole and the latter had to be filled which was rather ticklish job as it was well under Hun wire. This Chamber is required to give room to the use of the Wombat drilling machine
4/4/17 Wombat hole from I.54 is in 150 feet. Drilling has been stopped and preparations for loading in hand
5/4/17 Loading I.54 borehole continued. Loading in I.56 finished; it was loaded with 9lbs Ammonal per foot run continued in sheet iron cylinders. The length charged was 19 ft, the last 2 feet of the hole being tamped. The arrangement of firing was by two electric circuits with three detonators in series in each, placed in the last cylinder. The cover over borehole in I.56 and I.54 galleries was about 4 ft 6 in.
6/4/17 Borehole in I.54 loaded with 9lbs of ammonal per foot run contained in sheet iron cylinders, the hole is loaded for 144 feet the last 6 feet being tamped. The arrangement for firing is by 2 electric circuits, with 6 detonators in series in each; 3 detonators being in the middle of the charge and 3 at the back end.
9 April. The Battle begins with another entry in the Unit Diary.
9/4/17 At zero hour (5.30 am) the Mine in I 70 and boreholes in I 56 and I 54 were blown. The explosions of these Mines was taken as the signal to attack by the Infantry in the Neighbourhood.
At 156 the explosion produced a crater of about 10 ft deep, 30 ft across and 50 ft long…In 45 minutes a trench was opened from the crater to the Hun trench and 200 ft of Gallery Roof about 2 in thick removed, a clear trench way being established from our gallery and the Hun front line…In 154 the explosion produced a crater about 12 feet deep 44 ft across and approx 160 feet long…A communication trench was established from our gallery to the crater and to the Hun Line in 2 hours. These Communication trenches were never used as the attack was so successful that about a 4 and a half mile advance was made that day.
Image; Courtesy Australian War Memorial ID number EO1689. Date made 30 January 1918.
Image caption: Boring a hole with a ‘Wombat’ drill for the ventilation of a dugout at the Headquarters of No. 2 Section, 3rd Australian Tunnelling Company, in the Cite St. Laurent. The “Wombat” boring machine was designed by Captain Stanley Hunter of the Australian Mining Corps, and adopted by the British Army. Shown: Lieutenant J. Robertson (left) and 4368 Sapper C. G. Jolley, at work.