In response to the key technical challenges in the Zhangfushan Mining Area upper stratum， such as borehole wall instability and simultaneous drilling fluid leakage during drilling，which caused by complex geological conditions including stratum collapse， surface deformation， and groundwater drainage，the issue of borehole wall instability was overcome by optimizing the hole structure and combining it with the casing drilling process. Additionally， an innovative pressure-controlled check valve was introduced to regulate the dynamic pressure of drilling fluid， ensuring safe penetration through the upper complex formations. In the lower stable strata， a packed-hole wireline coring assembly was employed to achieve precise borehole trajectory control， ultimately successfully penetrating the target ore zones. Engineering practices demonstrate that this integrated approach provides technical references for core drilling in similar geological settings and supports the new round of strategic mineral exploration breakthrough initiatives.