Bauxite orebody demarcating and virtual mining for mining optimization within an underground bauxite seam, Southwest China

Bauxite grade is an important property determining the ore reserve, mining value and mining technology parameters within an underground bauxite seam, which is a prominent difference between bauxite and coal mines. An orebody demarcating approach was proposed to determine the top and bottom boundaries of bauxite orebody, which consists of the following steps: one-dimensional inverse distance weighted interpolation for grade distribution along each sampling trench or borehole, delimiting for orebody boundary according to the industrial constraints of bauxite grade, and two-dimensional biharmonic spline interpolation for boundary surfaces. Then, the 88,983 m³ bauxite orebody having an average thickness of 1.4565 m was demarcated in the 1102 longwall panel. The application of the fully mechanized longwall mining in the bauxite seam in Wachangping bauxite mine has been inferred to be feasible from the following comprehensive considerations: occurrence properties of orebody, geomechanical parameters of ore-rock, geological and hydrogeological conditions and overburden stability. In addition, the optimal cutting height on each longwall slice ranging from 0.9773 to 2.4276 m was determined by the proposed virtual mining procedure. The designed 1.2138-m-diameter cutting drum can satisfy the industrial requirements for the low-waste and high-recovery mining of underground bauxite, in which the average ore loss rate and roof waste mixing rate are merely 0.2367 and 5.1355%, respectively.