HE the Prime Minister and Minister of Interior Sheikh Abdullah bin Nasser bin Khalifa al-Thani yesterday attended  Qatar Rail’s celebration marking the completion of the tunnel digging works for the Doha Metro Project on the south side of the Red Line in Hamad International Airport (HIA) Station. The tunnelling works started in July 2014 and 111km were covered yesterday by the tunnel boring machine (TBM). Abdullah bin Abdulaziz Turki al-Subaie, managing director and chairman of the executive committee of Qatar Rail, said that the completion of the drilling works was an important milestone in  Doha Metro project’s progress.