Study on the possibility of using artificial pillar to replace the protection coal pillar of the preparation roadways during the mining process at underground coal mines in Quang Ninh region, Vietnam

The coal reserves in protection pillar of roadways are expected to be left in the mining process in underground mines in Quangninh coal basin which is relatively large (about 16% of the total reserves). If it can be exploited, it will help to save non-renewable coal resources, reduce the cost of preparing roadway meters, extend the mine life and increase the efficiency of construction investment. In the world, in order to reduce coal loss in protection pillar of roadways, mining technology to exploit and use artificial protection pillars are quite popular. Accordingly, in order to simultaneously exploit coal in the protection pillar and maintain the transport roadway as a ventilation roadway for the longwall in below level, the post-mining coal pillar will be replaced by artificial pillars formed from the stone backfill cribs, columns, metal cribs, chemical materials or low-grade concrete mortar mixes formed from fly ash, bottom ash of thermal power plants, combined crushed waste rock and a cement additive,... This paper will evaluate the possibility and propose a number of mining technological scheme as well as the type of construction materials suitable for artificial columns.