Tectonogeochemical features and metallogenic prognosis in the Xiaolongtan copper mining district, Binchuan, Yunnan Province, China

Abstract

The Xiaolongtan copper mining district is an important area in Dali, West Yunnan, where porphyry copper deposits occur, and copper orebodies are controlled by fault or contact zone structures between porphyry massifs and country rocks. Based on detailed field investigation and deep-going analysis, the authors systematically studied the tectonogeochemical features of this mining district, proposed the principle and foundation of metallogenic prognosis, and delineated the most potential mineralization target area.

Key technologies for improving resilience of super-large diameter shield tunnel affected by large variable loads underneath the Yellow River

“…For example, an accidental surface surcharge along a metro line in Shanghai caused excessive deformation of the tunnel lining, as shown in figure 1, resulting in concrete spalling, bolt fracture, joint expansion, and water leakage [10]. The neighboring construction activities also pose safety hazards and risks associated with the structural performance degradation of tunnels during operation [11][12][13][14]. In addition, riverbed erosion and seasonal changes in groundwater levels pose challenges to the safe operation of shield tunnels.…”