Kaolin Mining: Geological Genesis and Technical Challenges

Kaolin, as a crucial non-metallic mineral resource, is widely used in ceramics, papermaking, coatings, and other industries. Its mining technology and geological conditions directly affect resource utilization efficiency and safety. Taking the Yangdong kaolin deposit in Suzhou, China, as an example, the study of its ore body genesis and mining technical conditions provides scientific insights for optimizing extraction strategies.

The formation of the Yangdong kaolin deposit is closely related to medium-low temperature hydrothermal alteration and secondary reformation. The ore bodies are primarily hosted in volcaniclastic rocks (e.g., silicified tuff) and subvolcanic rocks (e.g., rhyolite porphyry), with hydrothermal activity dominating the mineralization process. During hydrothermal alteration, aluminum-rich silicate minerals (e.g., feldspar) transformed into kaolin under medium-low temperature conditions, accompanied by silicification, alunite alteration, and sericitization. For instance, veinlet and vermicular kaolin observed in ores indicate hydrothermal infiltration along fractures. Secondary leaching further enriched kaolin, particularly in the lower part of the ore body, where halloysite content significantly increased, forming high-quality ore layers. These geological characteristics not only reveal the complexity of mineralization but also offer critical clues for orebody positioning and grade evaluation.

Analyzing mining technical conditions requires comprehensive consideration of hydrogeological and engineering geological factors. The Yangdong deposit features two main aquifers: the Quaternary loose porous aquifer and the Carboniferous-Permian limestone (marble) aquifer. The former, distributed near the surface, consists of slope-alluvial deposits with low permeability; the latter, serving as the orebody floor, is buried underground with developed dissolution fractures and higher water yield. According to predictions using the tunnel analogy method, the normal water inflow at the -100m level is 68.62 m³/h, while the maximum inflow reaches 105.35 m³/h, primarily from limestone fissure water. Preventive measures, such as advance drilling, are essential to mitigate water inrush risks during mining. Additionally, groundwater recharge in the area relies mainly on atmospheric precipitation, with minimal influence from distant surface water bodies (e.g., Taihu Lake and the Grand Canal), reducing potential external water hazards.

Regarding engineering geology, the surrounding rocks are predominantly silicified tuff and secondary quartzite, with rock integrity significantly affected by tectonic and alteration processes. For example, marble in areas intersected by dykes exhibits high fragmentation, with over 80% of core fragments smaller than 5 cm, necessitating robust support designs to ensure stability. Environmental assessments indicate favorable overall conditions, though long-term tailings management and ecological restoration plans are crucial to minimize impacts on the surrounding environment.

Based on these analyses, the mining technical conditions of the Yangdong kaolin deposit are classified as Type II-2, indicating moderate hydrogeological and engineering geological complexity. To enhance mining efficiency and safety, the following measures are recommended: First, optimize drainage system design, dynamically adjusting water management based on real-time monitoring data. Second, introduce mechanized mining equipment to reduce disturbance to unstable rock layers. Third, promote tailings resource utilization by converting waste into construction materials, achieving both economic and environmental benefits.

Kaolin mining is not merely the extraction of geological resources but a comprehensive test of technical and managerial capabilities. From genesis interpretation to practical implementation, each step must balance scientific rigor and sustainability. Only through a deep understanding of deposit characteristics and precise risk control can the industry achieve safe, efficient, and environmentally balanced kaolin resource development.