High-density drilling exploration method for pillar setting in thin bedrock areas of coal mines and rationality discussion

Abstract:

Drilling is one of the key methods for investigating water inrush and sand gushing disasters in coal mines. However， the Detailed Rules for Prevention and Control of Water Hazards in Coal Mines only stipulates a minimum requirement of two surface boreholes in thin-bedrock areas， while underground drilling density relies entirely on the self-discipline of related coal mines. This regulatory framework allows those designs based on limited exploration boreholes easier to meet compliance requirements， yet still leaves potential water inrush and sand gushing risks in mining. Taking the 16031 panel in the northern wing of Liuhe Coal Mine as a case study and proceeding from potential disaster-inducing risk conditions， this paper discusses the necessity of increasing both surface and underground drilling density， summarizes its rationale， and reveal the effectiveness of enhanced drilling density in water hazard detection and control. The study concludes that two surface boreholes in thin-bedrock areas represent the regulatory baseline requirement. The density of surface and underground exploration boreholes should be comprehensively determined by factors including coal-bearing stratum undulations， ancient erosion surface morphology， bedrock weathering depth， fault structures， and geophysical anomaly distributions. Increasing drilling density for hydrogeological precise and detailed investigation is deemed essential. The increase in borehole density should be proposed based on the results of the previous exploration and targeted at unidentified risk sources. Appropriately increasing surface boreholes while fully utilizing underground boreholes proves to be an effective approach for investigating water inrush and sand gushing hazards as well as risk investigation.