172nd Tunnelling Company included a significant number of miners from
South Wales, as did the
184th,
170th,
171st,
253rd and
254th Tunnelling Company. From its formation in April 1915 until the end of the war the company served under
First Army south of the
Ypres Salient.
Ypres Salient Following its formation, 172nd Tunnelling Company was first employed in the area of
St Eloi and
The Bluff at
Ypres, With the additional height in an otherwise relatively flat landscape, The Bluff was an important military objective. German forces took The Bluff in February 1916. In addition to The Bluff, 172nd Tunnelling Company was also responsible for mining at
St Eloi south of Ypres. At
St Eloi, military mining began in early 1915. The Germans had built an extensive system of defensive tunnels and were actively mining at the intermediate levels. In March 1915, they fired mines under the elevated area known as
The Mound just south-east of St Eloi and in the ensuing fighting (the
Action of St Eloi, 14–15 March 1915) the British infantry suffered some 500 casualties. A month later, on 14 April 1915, the Germans fired another mine producing a crater over in diameter. After these experiences, the British started an extensive programme of defensive mining at St Eloi to protect the British trenches from future German mines, but also included offensive elements by placing large attack mines beneath the German trenches. Much of this work was done by the
177th Tunnelling Company and the 172nd Tunnelling Company, the latter commanded in early 1915 by Captain
William Henry Johnston VC. Johnston left 172nd Tunnelling Company in early May, when he was succeeded as officer commanding by William Clay Hepburn, a
Territorial Army Captain in the
Monmouthshire Regiment. Hepburn was a mining engineer and colliery agent in civilian life, and the first non-regular Royal Engineer officer to command a Tunnelling Company. The officer in charge of 172nd Tunnelling Company's offensive mining activities at St Eloi was Lieutenant Horace Hickling, who would go on to command
183rd Tunnelling Company on the
Somme in 1916, supported by Lieutenant Frederick Mulqueen, who would go on to command
182nd Tunnelling Company at
Vimy in 1917. The geology of the Ypres Salient featured a characteristic layer of sandy clay, which put very heavy pressures of water and wet sand on the underground works and made deep mining extremely difficult. In autumn of 1915, 172nd Tunnelling Company managed to sink shafts through the sandy clay at a depth of down to dry blue clay at a depth of , which was ideal for tunneling, from where they continued to drive galleries towards the German lines at a depth of . This constituted a major achievement in mining technique and gave the Royal Engineers a significant advantage over their German counterparts. Meanwhile, at
The Bluff, mining was continued by the 172nd Tunnelling Company and in November 1915,
John Norton-Griffiths proposed to sink 20 or 30 shafts, about apart, into the blue clay from St Eloi to The Bluff. On 21 January 1916, German miners blew several large charges at The Bluff, which caused 172nd Tunnelling Company to halt its work on the shallow galleries in St Eloi in order to complete the deep mines as soon as possible. On 14 February, the German infantry succeeded in capturing The Bluff from the British and advanced towards St Eloi, raising fears that the British deep mines might be captured before they could be fired. The British decided to use the deep mines created by 172nd Tunnelling Company at St Eloi in a local operation (the
Battle of St Eloi Craters, 27 March – 16 April 1916) and six charges were prepared. There were four central mines, of which two were laid from shaft D and two from shaft H. The largest, code-named
D1, contained of
ammonal and was placed beneath
The Mound, while the mines code-named
D2, H1 and
H4 were charged with between and . The two flanking mines, code-named
I and
F, were significantly smaller charges laid short of the German front line. For most of the time, the British preparations were severely obstructed by highly efficient German counter-mining. When the mines were fired at 4.15 a.m. on 27 March 1916,
D1 and
D2 were detonated first, followed by
H1 and
H4, then
I and finally
F. To witnesses it "appeared as if a long village was being lifted through flames into the air" and "there was an earth shake but no roar of explosion". The detonation obliterated
The Mound and killed or buried some 300 men of the 18th Reserve Jäger Battalion; two miles away, at Hill 60, the trenches rocked and heaved. The
Royal Northumberland Fusiliers attacked and held the
D1, D2 and
F craters, but efforts to dig communications trenches to their positions failed under the heavy German fire, the muddy ground and debris thrown up by the explosions. British attempts to gain a line beyond the craters were unsuccessful for a week but eventually took the four central craters in the early morning of 3 April, shortly before the
3rd Division was relieved by the
2nd Canadian Division. A German counter-attack during the night of 5 April captured the craters, and the Canadians were ordered to withdraw. The operation had been a failure and the advantage of the mines had been lost; the problem lay in the problem of integrating mines into the attack and the Allied inability to hold crater positions after they had been captured. It also demonstrated that holding a crater against concentrated fire and determined German counterattack was extremely difficult. In March 1916, 172nd Tunnelling Company handed its work at St Eloi over to
1st Canadian Tunnelling Company. It then relieved
181st Tunnelling Company in the
Rue du Bois area, but soon moved back to
The Bluff. As part of this process, the
New Zealand Tunnelling Company took over a sector between
Roclincourt and
Écurie from the French ''7/1 compagnie d'ingénieurs territoriaux
during March 1916. On 29 March 1916, the New Zealanders exchanged position with the 185th Tunnelling Company and moved to Roclincourt-Chantecler, a kilometre south of their old sector. The original plan had called for 17 mines and 9 Wombat
charges to support the infantry attack, of which 13 (possibly 14) mines and 8 Wombat'' charges were eventually laid. In order to assess the consequences of infantry having to advance across cratered ground after a mining attack, officers from the Canadian Corps visited
La Boisselle and
Fricourt where the
mines on the first day of the Somme had been blown. Their reports and the experience of the Canadians at
St Eloi in April 1916 – where mines had so altered and damaged the landscape as to render occupation of the mine craters by the infantry all but impossible –, led to the decision to remove offensive mining from the central sector allocated to the Canadian Corps at Vimy Ridge. Further British mines in the area were vetoed following the blowing by the Germans on 23 March 1917 of nine craters along
no man's land as it was probable that the Germans were aiming to restrict an Allied attack to predictable points. The three mines already laid by 172nd Tunnelling Company were also dropped from the British plans. They were left in place after the assault and were only removed in the 1990s. Another mine, prepared by
176th Tunnelling Company against the German strongpoint known as the Pimple, was not completed in time for the attack. The gallery had been pushed silently through the clay, avoiding the sandy and chalky layers of the Vimy Ridge, but by 9 April 1917 was still short of its target. In the end, two mines were blown before the attack, while three mines and two
Wombat charges were fired to support the attack, including those forming a northern flank. In early 1918 half of
252nd Tunnelling Company, arriving in the Vimy Ridge sector from
Beaumont-Hamel, was attached to 172nd Tunnelling Company.
Somme sector March 1918 saw 172nd Tunnelling Company working on a new defensive line on the
Somme, near
Bray-Saint-Christophe. It fought as emergency infantry near Villecholles, where it carried out a fighting retreat.
Amiens 1918 In April 1918, troops of 172nd Tunnelling Company fought a large fire in
Amiens. ==Memorial==