Blind Shaft Mining

Blind shaft mining is a variation of blind shaft boring that has to do with drilling big length boreholes from surface but without drilling a pilot hole. Blind shaft boring is a demonstrated mine development method that is utilized a great deal for excavating ventilation shafts in coal mining. Moving this mine development technology into production mining has to do with drilling a big diameter access hole with the blind shaft boring machine, and then consequently increasing and excavating a large size hole, in general three to four metres in diameter, all the way through the ore body by utilizing an reamer that expands. The rock in the ore possibility is drilled by revolving a weighted expandable curved cutter head against the rock. The cutting head is turned from the top by the drill pipe, which can also be used as a channel to move the cuttings from the bottom of the shaft to the top, where uranium ore can then be recovered. The drill pipe is utilized to suspend the drilling gathering in the hole and is tensioned to regulate the cutting weight on the head and maintain the drill pipe straight and in place. The drill channel’s ascending flow of water is triggered by compressed air that is inserted down the middle of the drill pipe. On the top, through a sequence of settling ponds, the water is unconnected from the cuttings and placed back into the hole. Every reamed hole or cavity is filled back after completion. A cemented combination is utilized to backfill the mineralized possibility where the mined out cavity is expanded and excavated to a bigger diameter by the expandable reamer. The un-mineralized drill cuttings are utilized to backfill the rest of the hole, which is smaller in diameter, through the overlying sandstone and glacial overburden layers.