Thirty men from each of the three Australian Tunnelling companies were separated to become the Australian Electrical & Mechanical Mining & Boring Company. They became known as the 'Alphabet Company', and the men who served were referred to as the Alphabeticals.
The Alphabet Company played a major role in building and repairing equipment, including the installation of lightings in some undergrond workings, and testing electrical blasting circuits when called upon.
The Australian Electrical & Mechanical Mining and Boring Company were at Tor Top, during the Third Battle of Ypres and had its engine room up near the front line (in a below-ground dugout near the road leading back to Zillebeke). It was one of the worst gassed parts of the line and the Alphabet Company made and installed a large gas filter chamber that was fitted in a gallery below ground and could filter 850 cubic metres of air per hour drawn in from the outside air and into the galleries, in addition to pumping water from the galleries. The company also put in 232 lighting points in the dugouts and galleries at Tor Top and Observation Ridge just back along the Zillebeke Road. In the words of the Alphabet Coy "the approach to Tor Top was extremely difficult many casualties occurring whilst transporting stores and plant". It would have been worse for the Canadian miners there. 
- https://www.awm.gov.au/sites/default/files/phantom-soldiers-tunellers.pdf, accessed 05/01/2014.
- Thomas, Ross, Underground: A Tribute to the Tunnellers of the Great War 1914-1918, SP, 08 July 1994.
- Research by Damien Finlayson, 16 July 2014.