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High-steep gently inclined mining slopes, prevalent globally, often suffer significant deformation, leading to landslides due to numerous goafs. This research investigates the critical role of goaf location in controlling deformation, failure mechanisms, and disaster evolution, vital for safe mining practices. Through field investigations and model generalization in Guizhou, a physical model test method was used to study three positions of goafs: under the shoulder and foot of the slope, under the slope shoulder, and within the slope. Findings highlight the stronger influence of the goaf's mutual position with the slope shoulder on slope and overburden deformation and failure compared to the slope toe. Deformation and failure modes evolve from collapse toppling to collapse slip and collapse settlement as the goaf shifts from the near slope surface to inside of the slope. Statistical analysis of fracture distribution in the goaf's overlying strata reveals damage increase with larger goafs, following a Gaussian distribution, with concentrated damage in the middle. The study identifies the maximum damage area, influenced by the horizontal distance between the goaf center and slope shoulder. These insights advance understanding of overburden rock deformation in gently inclined high-steep mining slopes., (© 2024. The Author(s).)

A new reversed phase ultra performance liquid chromatography (UPLC) method was developed for the rapid quantification of three curcuminoids (curcumin (C), desmethoxycurcumin (DMC) and bisdesmethoxycurcumin (BDMC)) in Curcuma longa Linn. (C. longa) using a Waters BEH Shield RP C(18), 2.1 mm x 100 mm, 1.7 microm column. The runtime was 2 min. The influence of column temperature and mobile phase on resolution was investigated. The method was validated according to the ICH guideline for validation of analytical procedures with respect to precision, accuracy, and linearity. The limits of detection were 40.66, 49.38 and 29.28 pg for C, DMC and BDMC, respectively. Limits of quantitation for C, DMC and BDMC, were 134.18, 164.44 and 97.50 pg, respectively. Linear range was from 3.28 to 46.08 microg/ml. The mean+/-SD percent recoveries of curcuminoids were 99.47+/-1.66, 99.50+/-1.99 and 97.77+/-2.37 of C, DMC and BDMC, respectively. Comparison of system performance with conventional HPLC was made with respect to analysis time, efficiency and sensitivity. The proposed method was found to be reproducible and convenient for quantitative analysis of three curcuminoids in C. longa. This work provided some references for quality control of C. longa., (Copyright 2010 Elsevier B.V. All rights reserved.)