North China University of Water Resources and Electric Power

• Establishes the first precise mineralization age (230–240 Ma, Middle Triassic) for the Juyuan tungsten deposit using multi-method geochronology (in-situ zircon and wolframite/scheelite U-Pb, and muscovite Ar-Ar dating). • Identifies a coeval, highly fractionated I-type granite (242.0 ± 1.2 Ma) as the metallogenic source, formed in a post-orogenic intraplate extensional setting. • Extends the East Tianshan Triassic tungsten belt eastward, revealing significant quartz vein-type tungsten potential in the western Beishan orogenic belt. The Beishan Orogenic Belt, situated on the southern margin of the Central Asian Orogenic Belt, represents a significant endogenous metallic mineral resource base in northwestern China. Previous studies have indicated that tungsten mineralization in the Beishan Orogenic Belt primarily occurred from the Early Silurian to Middle Carboniferous. However, whether quartz vein-type tungsten mineralization developed during the Middle Triassic remains controversial. This study focuses on the newly discovered Juyuan tungsten deposit in the western segment of the Beishan Orogenic Belt. We investigated the geological characteristics, tectonic setting, and timing of magmatism and mineralization, establish a metallogenic model for the Juyuan deposit, and compare it with typical regional tungsten deposits to provide guidance for future mineral exploration through systematic fieldwork, geochemical analyses, and isotopic geochronology, and show that the zircon U-Pb age of the monzogranite in the mining area is 242.0 ± 1.2 Ma. The granite exhibits high SiO 2 , high alkalinity, high Al 2 O 3 , and low CaO characteristics, identifying it as a highly fractionated I-type granite formed in a post-orogenic intraplate extensional setting. The 40 Ar- 39 Ar plateau age of muscovite from the ore-bearing quartz veins is 239.97 ± 0.98 Ma, while the insitu U-Pb ages of wolframite and scheelite are 232 ± 14 Ma and 236 ± 24 Ma, respectively, collectively constraining the mineralization age to between 230 and 240 Ma. This study demonstrates that the Juyuan tungsten deposit is a quartz vein-type tungsten deposit closely related to magmatic-hydrothermal processes. The East Tianshan Triassic tungsten metallogenic belt can be extended eastward into the Beishan Orogenic Belt, indicating significant potential for exploring quartz vein-type tungsten deposits in an intraplate extensional setting in its western segment.

Aims: This study aims to conduct a comprehensive static analysis and lightweight multi-objective optimization of the spiral sorting device (auger) used in coal mine roadway concrete pavers. The primary objective is to fundamentally enhance the economic efficiency, structural reliability, and operational stability of the equipment under the harsh, confined, and demanding underground environments typical of modern coal extraction facilities. Study Design: A rigorous numerical computational design combining advanced Finite Element Analysis (FEA) and statistical Response Surface Methodology (RSM) was deployed to systematically evaluate and optimize the mechanical structure. Methodology: Initially, a rigorous mesh independence verification was discussed to ensure the absolute accuracy and computational efficiency of the numerical solutions. Subsequently, a detailed static analysis was performed by fixing both ends of the spiral shaft to simulate bearing constraints, applying a substantial surface load of 15000 N on the active faces of the spiral blades to simulate concrete resistance, and subjecting the spiral shaft to a driving torque of 573 N·m. Building upon the baseline static analysis results, a central composite design (CCD) was employed to construct a accurate mathematical response surface model. The spiral shaft diameter and blade thickness were selected as independent design variables, while the total structural mass, maximum total deformation, and maximum equivalent stress were established as the targeted objective functions. Finally, a Multi-Objective Genetic Algorithm (MOGA) was utilized to navigate the complex design space for global optimal searching based on Pareto efficiency. Results: The initial comprehensive static analysis indicated that the maximum equivalent stress of the spiral sorting device was intrinsically located at the root of the blade, peaking at 126.46 MPa. Concurrently, the maximum deformation was recorded at 1.2891 mm at the outermost blade tip. Both baseline values fully met the rigorous safety design requirements. Detailed sensitivity analysis subsequently revealed that the spiral shaft diameter possessed the most significant dominant impact on both total mass and structural deformation, whereas the blade thickness exerted a more pronounced, localized influence on the stress distribution at the blade roots. Through extensive MOGA optimization iterations, the optimal geometric parameters were mathematically determined and engineering-rounded to a shaft diameter of 44 mm and a blade thickness of 4 mm. Consequently, the mass of the newly optimized device was remarkably reduced from an initial 28.411 kg down to 23.056 kg. Simultaneously, the maximum stress increased to 196.56 MPa and the maximum deformation shifted to 2.4121 mm, both of which dynamically remain strictly and safely within the allowable physical limits of the selected material. Conclusion: The optimized design strategy successfully and significantly reduced the unnecessary dead mass of the spiral sorting device, achieving the coveted lightweight construction without compromising the essential structural strength and operational stiffness. This in-depth research provides a solid theoretical foundation, robust numerical validation, and a practical engineering reference for the future development, upgrading, and manufacturing of intelligent paving equipment operating under severely constrained underground conditions.