Abstract
Sublevel caving (SLC) is widely used in underground mines for its low cost and high production rate, but it faces challenges such as high ore loss and dilution. The previous research has focused on shape of draw bodies, stope structural parameters of SLC and drawing management. However, the flow of waste rocks, ore-rock contact and its control in the drawing process are not deeply studied. This study analyzed the main causes of these issues and the formation mechanism of waste rock funnels, proposing the insert drawing method (IDM) to reduce ore loss and dilution. This technique involves actively controlling the contact, movement direction, and path of ore-rock near the drawpoints using an insert device. By manipulating insert device, the technique effectively enhances ore flow velocity and area, resulting in enhanced ore recovery. By managing the movement of waste rock funnel, the technique can delay dilution entry in the drawpoints, effectively reducing ore dilution. Further, to validate IDM's effectiveness, comparative experiments were conducted between IDM and traditional cut-off grade drawing method (COGDM). The experimental results indicate that IDM outperforms COGDM in terms of ore recovery rate. For the mining of massive orebodies with SLC, IDM achieves a 10.96% higher ore recovery rate compared to COGDM; for steeply inclined medium-thick orebodies, IDM's ore recovery rate surpasses COGDM by 15.68-30.88%. The research demonstrates that IDM effectively reduces ore loss and dilution in SLC, making it suitable for widespread application in other SLC mines.