OSSA is the leading company in the Spanish market in underground projects in Mining, Civil Engineering tunneling (Road, Rail and Subway/Metro tunnels), Underground Hydraulic Projects, and Underground Hydro Power Plants.

The company was founded in 1952. Through more than 60 years of continued specialization and innovation the company has earned an international reputation for designing and building the most complex underground projects, in difficult soil conditions, working in remote locations, with tight budgets and challenging project schedules. Our significant construction outputs and efficiency, along with the quality of our projects, are recognized worldwide.