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Tu Hong-Sheng, Tu Shi-Hao, Zhang Cun, Zhang Lei and Zhang Xiao-Gang

Abstract

A steep seam similar simulation system was developed based on the geological conditions of a steep coal seam in the Xintie Coal Mine. Basing on similar simulation, together with theoretical analysis and field measurement, an in-depth study was conducted to characterize the fracture and stability of the roof of steep working face and calculate the width of the region backfilled with gangue in the goaf. The results showed that, as mining progressed, the immediate roof of the steep face fell upon the goaf and backfilled its lower part due to gravity. As a result, the roof in the lower part had higher stability than the roof in the upper part of the working face. The deformation and fracture of main roof mainly occurred in the upper part of the working face; the fractured main roof then formed a “voussoir beam” structure in the strata’s dip direction, which was subjected to the slip- and deformation-induced instability. The stability analysis indicated that, when the dip angle increased, the rock masses had greater capacity to withstand slip-induced instability but smaller capacity to withstand deformation-induced instability. Finally, the field measurement of the forces exerted on the hydraulic supports proved the characteristics of the roof’s behaviors during the mining of a steep seam.

Open access

Lei Zhang, Zhiwei Ye, Jun Tang, Dingyi Hao and Cun Zhang

Abstract

As a kind of associated geological gas, coalbed methane (CBM) is mainly adsorbed in the coal seam. The coal-methane adsorption phenomenon can be described by Langmuir monolayer adsorptio n model, BET multilayer adsorption model and the Theory of Volume Filling of Micropore (TVFM), whereas the binary gas adsorption phenomenon can be described by the extended Langmuir Model. For the CBM in the low permeability coal seam, the amount of gas released by direct drainage is relatively limited, which cannot eliminate the gas explosion and outburst hazards. Gas injection is an effective method to promote methane drainage. In this paper, the free desorption and nitrogen injection displacement experiments are comparatively analyzed, which allows verifying the effectiveness of nitrogen injection’s enhancement to gas drainage. The experiment of injecting nitrogen gas into the coal body shows that the coal fracture can be maintained or expanded by the injected gas pressure so that more methane can be released. The nitrogen injection has a higher time efficiency than that of free desorption as well. The displacement ratio of N2/CH4 is in the range of 1-3. Both the injection pressure and confining pressure affect the displacement ratio. The analysis of the desorbed gas components shows that the relationship between the methane component and gas flooding time is an “inverted S” shape curve, and the appropriate time for the methane collection can be inferred by the time interval of the rapid decline of the curve.

Open access

Wen Xie, Hong Zhao, Yu Chen, Qin Zhang, Wei Lu, Wei Liu, Ai-rong Hu, Han-wei Li, Ping Feng, Ming-sheng Chen, Cun-jin Mei, Xiao-lin Guo, Xiao-hu Zhao, Jiang-bin Wang, Zheng-qin Fan, Jian-he Gan, Qing Xie and Jun Cheng

Abstract

Obejective Ademetionine 1,4-butanedisulfonate [S-adenosyl-L-methionine (SAMe)/Transmetil®, Abbott] has been available in China for more than 15 years, and it has been shown to reduce serum bilirubin and transaminase levels in viral hepatitis (VH) patients. However, no large-scale studies have focused on the impact of SAMe treatment regimen on reducing the serum total bilirubin (TBil) in VH patients with intrahepatic cholestasis (IHC). The primary purpose of this study was to evaluate the effectiveness of intravenous SAMe (Transmetil®) treatment in reducing the serum TBil by 50%.

Methods This retrospective, multi-center, cross-sectional medical record review involved patients aged ≥18 years. Records of 1 280 hospitalized VH patients at 16 sites diagnosed with IHC who had received intravenous SAMe 1 000 mg or 2 000 mg q.d. for at least 7 days from January 1, 2006 to June 30, 2009, were screened and 905 records were randomly selected.

Results The safety set (SS) included 834 patients and the full analysis set 826 patients. TBil levels after 14 days injection treatment were available for 763 patients. TBil decreased ≥ 50% versus baseline after 14 days treatment in 288 (37.7%) patients (95% CI 34.3%, 41.2%). Twenty-nine non-serious adverse events (non-SAEs) were reported in 19 (2.3%) patients, and 29 SAEs were reported in 10 patients (1.2%). All adverse events (AEs) were considered unrelated to the study drug.

Conclusions This retrospective study shows that intravenous SAMe administration in VH patients with IHC is associated with significant reduction of TBil levels in more than 30% of patients 14 days after treatment initiation.