Ha Tien 1 Cement Co. yesterday broke ground for a factory with annual capacity of 2Mta in the southern province of Binh Phuoc.  The US$310m factory covering 77.8 hectares of land in An Loc District will be completed by the end of 2006, director Nguyen Ngoc Anh said.  Binh Phuoc is one of the two southern provinces that have limestone mines for cement production. The mine in Binh Phuoc, with total reserve of some 270Mt, will supply enough material for the company in 100 years.  The other mine is in Kien Giang Province and is being exploited by Ha Tien 2 and Holcim companies to turn out more than 2.5Mta of cement.