Khai Thac Che Bien Khoang San Lang Son Joint Stock Company Address: No 127, Ton That Tung Street, An Thinh Hamlet, Huu Lung Commune, Tinh Lang Son, Viet Nam Enterprise code: 4900943910 Phone: 0977973938 Representative: Hoang Viet Anh Huu Lung Commune, Huu Lung District, Lang Son ProvinceFounding date: 13 - 5 - 2026