Hydrodemolition. Technician operating a handset- controlled hydrodemolition machine. The machine is selectively removing concrete from part of the arching of the channel tunnel (Eurotunnel). The machine fires jets of water at pressures of up to 2000 atmospheres. The water is mixed with abrasives such as silica sand and garnet. The water jets can remove a section of the concrete which has been damaged but will leave the steel reinforcement (centre left) intact. The use of waterjets to remove damaged concrete means there is no build up high temperatures which can effect the metallurgical properties of the steel reinforcment.