The tunnel will be constructed using the drilling and blasting method, which is the most common method of excavating rock in Sweden. Work will be done in one week production cycles that can, in simple terms, be described as follows:
- Injection: To minimise groundwater leaking into the tunnel, long drill holes will be drilled into the rock around the tunnel and then sealed with concrete. Drilling will give rise to structure borne noise but the sealing work will be quiet.
- Volley drilling: Five metre deep drill holes will be drilled in the front of the tunnel This drilling will give rise to structure borne noise.
- Charging and blasting: The drill holes will be charged with explosives and blasting will be performed, which will give rise to noise and vibrations.
- Ventilation, loading and transport: The tunnel will be ventilated to extract blasting gases. The fans can be heard in the proximity of the worksite area. The rock rubble will then start to be loaded onto trucks, this will be done in the tunnel and therefore will not be intrusive on the surrounding area. On the other hand, truck movements will be noticable on the roads around the worksite area.
- Clean up and rock reinforcement: One final stage of the production cycle will be to clean up the new tunnel section, which means a hydraulic hammer will hammer at any loose rock to dislodge it. The rock will also be reinforced to ensure the tunnel is stable and safe. Both these processes give rise to structure borne noise.