In recent months, and now years, column inches have been devoted to rocketry. One fi gure in particular, familiar to tunnellers is Elon Musk, whose private company SpaceX is making great strides in reducing the cost of launching to Low Earth Orbit.

Readers may also be familiar with his challenge to the tunnelling industry to reduce its costs by an order of magnitude to make Hyperloop a feasible prospect for wider investment. And Tunnels and Tunnelling is aware that this challenge may be taken on by a team of engineers in the coming months.

But it is the science of the small that should not be ignored this month, as shaft excavation work for the High Luminosity Large Hadron Collider extension project (HiLumi) has begun.

This tranche of work is split between two sites, ‘Point 1’ and ‘Point 5’ on the famous particle-colliding ring. Point 1 is in Switzerland and is being handled by Marti Tunnelbau. Point 5 is in France and is being carried out by Implenia-Baresel.

The sites are nearly identical, and will require a shaft 10m in diameter and 85m deep; a cavern 15m in diameter and 50m long at the bottom of the shaft; a main gallery 300m long, starting at the cavern and running parallel to the existing LHC tunnel; four secondary galleries 50m long, starting at the main gallery and connecting to the existing LHC tunnel at 100m depth, with access stairs; and vertical cores to connect the secondary galleries to the existing LHC tunnel (for equipment feed lines).

As for surface works, fi ve industrial buildings to house the necessary accelerator upgrade equipment are called for, as well as technical galleries to connect all buildings to the shaft, and run the services into the underground spaces.

The contracts were awarded in early 2018, site preparation began in April and shaft excavation began in August. Cavern excavation is expected to begin in H1 2019 and tunnel excavation and lining should run from H2 2019 until mid-2021.

There is not suffi cient space here to cover the science behind the upgrade to CERN, in short, the project is a power upgrade, that aims to increase the number of collisions. Interested readers can peruse the website for more of the science: The science is underground, and depends on underground construction. It is often forgotten that tunnelling is vital for solving problems that are at the limits of human understanding, as well as the everyday challenges of keeping our cities moving