Khai Thac Che Bien Khoang San Tien Son Joint Stock Company Address: Dong Lai Hamlet, Huu Lung Commune, Tinh Lang Son, Viet Nam Enterprise code: 4900943565 Phone: 0936970119 Representative: Bui Quang Hung Huu Lung Commune, Huu Lung District, Lang Son ProvinceFounding date: 5 - 5 - 2026