Investigation and Evaluation Report of the "28" Mountain Landslide Disaster in Yunlian County, Sichuan Province Released

On February 8, 2025, at 11:50 am, a sudden mountain landslide occurred in Group 2 of Jinping Village, Mu'ai Town, Yunlian County, Yibin City, Sichuan Province, resulting in 10 deaths, 19 missing persons, and 2 injuries. The report states that after expert technical verification, the "2.8" mountain landslide in Yunlian County, Yibin, Sichuan, was a complex natural disaster caused by a steep slope being continuously infiltrated by persistent rain, causing the mudstone to soften and resulting in a sudden high-level landslide that converted into a remote debris flow. The slope is steep and almost vertical, with interbedded sand mudstone, varying hardness, fractured structure, and developed fissures. Under the long-term weathering and unloading effects, the rock mass loosened and deformed. With the continuous infiltration of groundwater due to persistent rain, the mudstone softened, reducing the stability of the mountain and leading to a sudden landslide. Through comprehensive investigation and analysis including ground measurements, mine surveys, 3D laser scanning and modeling, interpretation of multi-source satellite remote sensing data, automated deformation monitoring, rock and mineral tests, and discussions and visits, it was concluded that the impact of coal mining activities on the surface was minimal. As of now, no direct link has been found between mining activities and the mountain landslide.