• Road Tunnels
• Sewage Tunnels
• Power Tunnels
• Water Conveyance Tunnels
• Shafts

STFA constructed the Doha Metro Gold Line Project, which is the largest single item contract undertaken abroad by Turkish Contractors. The project, which has a contract value of 3 billion 400 million dollars, consists of the construction of 10 stations and 23 kilometers of tunnel.

STFA has in excess of 45 years of experience in tunneling and has completed over 130 kms of tunnels in varying soil conditions and terrain, including soft ground conditions and hard rock strata. STFA has the know-how and the equipment to implement various tunneling techniques, including TBM, conventional drill and blast, full face, road-header tunnel boring machines, and pipe-jacking.

The company provides turnkey services for tunnel projects.


• Doha Gold Line Metro, Qatar
• Melen Bosphorus Tunnel Crossing, Turkey
• 22 km of Istanbul Sewerage Tunnel Network, Turkey
• İzmit By-Pass Motorway Tunnels, Turkey
• Submarine shelters on the Black Sea coast, Turkey
• 15 km of tunnels in the Holy City of Makkah, Saudi Arabia
• Gandaf Hard Rock Tunnel, Pakistan
• Lakhdaria Motorway Tunnels, Algeria
• Several underground military shelters, Libya