Second Erjos tunnel, the core of Tenerife Island Ring, completed

Two months following the discovery of the initial openings in the North and South, drilling is now complete for the second parallel tunnel between Santiago del Teide and El Tanque Bajo.

After an extensive period of three years and eight months, the second Erjos tunnel is now complete. Situated under the Teno massif, the tunnel runs parallel to the first tube, which was successfully drilled on 26 June. In contrast to the earlier completion, this time the Department of Public Works, Housing and Mobility chose to forego a formal ceremony, opting instead to announce the milestone via an official press statement.

The drilling process was complex, relying chiefly on blasting techniques. Robotised excavators were also deployed, their use dictated by the varying conditions of the terrain. The work was strategically divided into two key phases, aiming to alleviate the pressure on the ground during the stabilisation of the tunnel’s vault. The first phase tackled the upper part of the tunnel, while the second, known as ‘destroza’, focused on the remaining lower part, according to information from the Regional Ministry.

Second Erjos tunnel, the core of Tenerife Island Ring, completed.
This is the drilling robot that works in the longest tunnel in the Canary Islands / DA.

The completed double tunnel measures 4,855 metres in length and will feature two additional ‘false tubes’: one at the southern entrance measuring 140 metres and another in the northern area spanning 100 metres. These extensions will make this project the longest tunnel in the Canary Islands, as well as one of the largest and most expensive road infrastructures currently under construction in Spain. The Canary Islands Government has highlighted its importance, stating it will meet “investment volume and the social, economic and mobility needs.”

Traffic projections paint a promising picture. By the start of 2025, it is anticipated that 17,000 vehicles will traverse the dual carriageway each day. Technical assessments suggest that this daily figure will likely double within the subsequent decade. The tunnel is poised to play a critical role in alleviating traffic congestion on the TF-5 Northern motorway, thereby enhancing economic activity between the island’s North and South regions. Moreover, it promises to substantially improve safety measures and reduce travel time for motorists. Specifically, journeys between El Tanque and Santiago del Teide are expected to be shortened by an average of 20 minutes when compared to the existing TF-82 mountain road.

To bring this colossal infrastructure project to life, a workforce of up to 300 specialised personnel was enlisted. They operated state-of-the-art drilling machinery, working in three daily shifts lasting eight hours each, seven days a week.

Tenerife Tunnel: 256 Million Euros

Financially, the project has a budget of 256 million euros. This figure represents an increase of 15 million euros from the initial cost, owing to price updates. An additional 18 million euros have been allocated for environmental mitigation efforts in the areas surrounding the construction site. These funds will go towards habitat recovery and the restoration of the La Grama quarries and Bilma mountain, as well as the creation of a new park on Santiago del Teide’s urban edge.

As of the latest update, over 50% of the construction work is complete. The Department of Public Works, Housing and Mobility forecasts that the tunnel will be fully operational by the first half of 2025.

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