In China, longwall shearers have successfully been applied in bauxite mines and are operating well. This is the world’s first underground bauxite mining technique using this type of comprehensive mechanised mining technology. The key equipment supplier, China Coal Technology and Engineering Group Corporation (CCTEG), says it transforms coal mining machines into bauxite mining machines for extraction, achieving a mineral recovery rate of over 95% and a low depletion rate of less than 5%. Regular ore sections can produce more than 500,000 t annually.
The first bauxite mine in China to deploy longwall mining was the Wachangping Bauxite Mine in Wuchuan Country, Guizhou Province, beginning with the 1102 panel in 2018. The mine is owned by the State Power Investment Corporation (SPIC) and operated by its subsidiary Wuchuan Alumina, which went on to also apply what it calls Technology of Comprehensive Mechanized Excavation (TCME) at Dazhuyuan, one of its other major bauxite mines in Guizhou, in 2019. These mines are feeding a new alumina plant that began operation in late 2020.
The traditional method of underground bauxite mining mainly involves blasting which has low mineral recovery rates, high depletion rates, low mining efficiency, and high production costs. After eight years of exploration, CCTEG’s team proposed a layered section mining method, and a new small drum incline cutting process, which were all first-of-their-kind.
The bauxite mining field has the characteristics of multiple dissolution cavities, faults, and thin and discontinuous ore veins. It also has high hardness and strong erosion characteristics of alumina-rich bauxite ores and cemented soil materials. CCTEG developed a large cutting force low-speed mining system and long-life walking system. The application of these original technologies has significantly improved mining efficiency and grade while reducing production risks.
The new technology and equipment for mining medium to high hardness minerals has broad application prospects not only in bauxite, but also in the phosphate and potash mining industries.