Cavico Corporation has announced that its subsidiary, Cavico Hydropower, has completely broken through the main tunnel at the Dong Nai 4 hydropower project in Vietnam’s Lam Dong province. The tunnel, which Cavico excavated and constructed, is 2.9 miles long and 30.2ft in diameter.

In 2007, Cavico was appointed by the Vietnamese prime minister to be the lead contractor for tunnel works construction on Dong Nai 4. The plant, Cavico Hydropower’s first awarded tunnel project, contains the widest tunnel in Vietnam and is located in the Bao Lam district of Lam Dong Province. The twin-unit plant will have a 340MW annual capacity once it becomes operational. Electricity of Vietnam (EVN) has invested approximately $301M in the plant. Cavico’s contract was valued at $26.6M at the time of signing.

“We are pleased to achieve this major milestone at the Dong Nai 4 hydropower project,” said Hai Thanh Tran, vice president of Cavico. ”This is one of the country’s most critical hydropower projects, and EVN is one of Cavico’s most important strategic clients. We are proud of our recent accomplishments, including the completion of the headrace and incline tunnels at the Dong Nai 3 hydropower plant in December, as well as the completion of the headrace tunnel, surge shaft tank, water gates, and crossing bridge at the Song Tranh 2 hydropower plant in the same month. Construction at the Dong Nai 4 plant continues on schedule, and we remain focused on concreting and completing the works in a timely and efficient manner.”