... khai thac: Ngfiy 1 5-6 -1 908, doan tfi cay s l tdi cfiy so 71 dfide dfia vfio khai thfic; Ngay 1 5-4 -1 909, khai thfic tdi efiy so' 165; Ngay 1-5 -1 909, khai thae tdi cay so' 221: Ngay 1-6 -1 909, khai ... quyin Doan Vi^t Tri - Yen Bai dfii 83 km dfide dfia vfio khai thac 1-7 -1 904 Doan Yen Bai - Lao Cai dfii 140 km va dfidc dfia vfio khai thac 1-2 -1 906 Din thang 4-1 906, doan Viet Tri - Lao Cai dfide ... xay dung vfio nam 1901 vfi d i n 1 6-6 -1 902 tofin tuyen dfidc dfia vfio khai thac (6), thang 4-1 903 dfidc ehuyen giao eho Cdng ty nhfidng quyin khai thae Ngfiy 1 0-3 -1 903, doan Ha Ndi - Vi$t Tri dfii...