What is the purpose of a block caving pre-conditioning program?

The purpose of a block caving pre-conditioning program is to induce controlled fracturing within the orebody prior to the start of caving operations, facilitating easier and more predictable cave propagation, improving fragmentation, and increasing ore recovery. Block caving is an underground mining method that involves undercutting a large block of ore and allowing it to collapse under its own weight. Pre-conditioning is a process that weakens the orebody before caving is initiated, making it easier to break and cave. Pre-conditioning typically involves drilling a series of boreholes into the orebody and then injecting high-pressure water or other fluids into the boreholes to create fractures. This process, known as hydrofracturing, reduces the strength of the rock mass and makes it more susceptible to caving. Pre-conditioning can also involve blasting small charges in the boreholes to create fractures. The controlled fracturing induced by pre-conditioning facilitates easier and more predictable cave propagation. This means that the cave will progress more smoothly and evenly, reducing the risk of hang-ups or other problems that can disrupt the caving process. Pre-conditioning also improves fragmentation. The fractures created by pre-conditioning weaken the rock mass, making it easier to break into smaller pieces during the caving process. This results in improved ore handling and reduced processing costs. By improving cave propagation and fragmentation, pre-conditioning increases ore recovery. More of the ore is recovered during the caving process, reducing ore losses and increasing the overall profitability of the mining operation. Pre-conditioning is a crucial step in block caving operations, ensuring the success and efficiency of the mining method.