Hanoi, Apr 3 (Reporter) Four coal miners lost their lives and seven others were injured on Wednesday in a methane gas fire in Vietnam's northern province of Quang Ninh, Vietnam News Agency reported. The mine, which covers 23 square meters in Cam Pha city, was reportedly under excavation when the accident occurred. The mine operates under Thong Nhat coal mine company of the Vietnam National Coal and Mineral Industries Group. The seven injured workers were being treated at a local hospital. The case was under investigations...////...