Get to know our offices
around the world.


Calle Isla Graciosa 1,
2ª Planta - Puerta 4
28703 San Sebastián de los Reyes (Madrid). Spain.

+34 902 678 808/+34 91 782 34 00


Civil Engineering Tunnel Projects.
We have specialized in underground civil engineering projects (roadways, subways and railways) for over 60 years and we continue to focus on specialization through value engineering, technological advancement, and specialist professional training. OSSA is your ideal tunneling partner, with the best resources, and extensive international experience.
Hydro Power Tunnel Projects.
Some of our landmark projects include seven major underground hydroelectric power plants, some of which have been among the largest in Europe (CH Cortes-La Muela in Valencia and CH San Esteban in Orense). We are active in the power plant tunneling industry internationally..
Mining Infrastructure Projects.
We work for coal, copper, iron and potash mining corporations, and we have been involved in complex mine operation and mine infrastructure projects. We design and build vertical shafts, tunnels and adits, large caverns, underground workshops, and underground pump stations.
OSSA has a portfolio of more than €250 million, of which €180 million are allocated to international projects what means around 72% of its portfolio related to international development.
Consult our dossiers by area of activity:
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