On 8 December the company fired the first two charges and the following day they began three new tunnels. On the 12th, however, the Germans blew eight or nine charges and attacked, forcing the French out of their front line. A new location for mining was selected to coincide with an attack by the Garibaldi Regiment at the start of January 1915. Nine galleries were worked on night and day: by the New Year they had reached 45 or 50m in length. The company loaded a mine on the night of 4 January with 3,000kg of gunpowder. It was blown at 6.50am the following morning and followed by an infantry attack, which was successful.

A kilometre north-west the 1st Company of the Rhineland Pioneers prepared for a similar attack, which initiated a tit-for-tat series of mine blows. Several saps were pushed to within 2–3m of the French lines ready for charging. However, on 3 December, the day before the assault was due, the French blew a camouflet, trapping Corporal Steil and Pioneer Glöckners at the end of the sap. After several hours digging, Glöckners was found alive, but reaching Steil took longer as a tunnel had to be dug under heavy fire. It was not until 10pm that he was found, trapped but alive. Food was brought to him and at midnight he was finally brought to safety. The 2nd Rhinelanders prepared a larger attack for 17 December, in conjunction with the 2nd Company of the 16th Pioneers, in which they fired six charges, each of 60kg, from tunnels. The blows badly damaged the French front line, killing or wounding a number of the garrison. The remainder were too shaken to put up much resistance and the Germans took and held the ridge west of the Ravin de Mortier. The 1st Rhinelanders retaliated on Christmas Eve, blowing a charge that buried part of the French trench. On the 29th the French fired a charge that formed a crater in no man’s land, which the Germans occupied.⁸

In exceptional circumstances the terrain might allow the sap to approach unseen, as in an incident at the Meuse heights, in front of Varnéville, in November, described by a member of the Chasseurs Alpin in the French press:

As one cannot get close to the enemy in broad daylight, one gets the advantage of him underground. Our Chasseurs continually have shovel and pickaxe in hand. The captain, well-liked by his men, says little; but one morning, he lets slip a remark when, head against one of the loop holes, he studies a German blockhouse which each day is increasingly resembling a real stronghold. This threat is only 100 metres away. ‘There,’ says the captain, ‘a nest which it is imperative to blow.’

‘To blow this nest’ becomes an obsession. All brains deliberate and in the evening the solution is found.

At a certain point, undetected, a path will be cut out which will lead towards the blockhouse, which is just 20 metres from the cliff. The mountaintop overhangs there and completely conceals the flank.

The diggers will thus be out of sight. They will not be burdened by the spoil removed by the excavations, which it will suffice to throw into the valley.

One does not sleep this evening in the trench. The plan is discussed and when properly decided, the captain is informed. He is made to understand the minor details of the project, supplements them himself, when it appears to him that some important detail has been missed. Next morning, men are immediately picking, those following behind throw the spoil into the valley. In two hours, the course is determined. The enemy cavern must now be mined.

So far as space allows, the men, who are held in Indian file, on the warpath, dive into the underground hollow and, in turn, gouge out the earth and make it fly.

Then, in a hole dug vertically below the German blockhouse, they insert shrapnel shells and melinite, sticks of dynamite, and bags of powder. An artillery artificer comes to give the last helping hand to the preparations. The chamber evacuated, the fuse is placed, a Chasseur wants to fire it himself. All the Alpins are anxiously in their trenches. A premonition has made them put their noses to the loop holes. Time passes slowly.

Suddenly, the ground rises, an immense fissure unleashes a column of fire. Debris of stones, trees, of earth, of iron, fly in all directions. An infernal noise…

A vast cloud blots out the sky. Then when all is done, the Chasseurs approach: the enemy nest is blown up along with its occupants. (Anonymous French Chasseur Alpin).⁹

From 8 December, the Germans noticed more activity on the part of the French. In the Champagne, sapping and mining towards Hill 200 throughout November reached a critical point at the beginning of December. General de Langle, commanding the 4th Army, obtained permission on 8 December from General Joffre, the French commander in chief, to combine the mining with an infantry and artillery attack. This was limited to Hill 200 and took place that day at 1300 with the blowing of three mines. The 34th Division succeeded in taking the German front line trenches and held them against repeated German counterattacks. The same unit attacked on the 20th after the blowing of two mines.

On 10th December the French blew a mine from a sap attack on La Targette in the Vimy sector. General Pétain, commanding the 33rd Corps, ordered the response after documents were found on the body of a German officer indicating that the 1st Bavarian Division planned a vigorous attack by sapping and mining on the village of Ecurie. The French seized the resulting crater and mine warfare was initiated on either side of the Lille road, which lasted all winter and into the spring of 1915.¹⁰ North of the Somme, mining warfare began at Beaumont when the French blew a German listening gallery on 17 December and the Germans blew their first mine on 3 January 1915 using 110kg of Donarit, a commercial ammonium nitrate blasting explosive.