Gas drainage efficiency improvement by increasing coalbed permeability using waterjet cutting system

This paper presented a method to create artificial fractures along the existing gas drainage borehole and increase the permeability of the coalbed using a high pressure waterjet cutting system.The field work conducted in Rujigou Colliery, Shenhua Ningxia Coal Group demonstrate that the coalbed permeability is increased, and accordingly, gas drainage efficiency is improved up to 3 to 6 times over the traditional methods using high pressure waterjet technique.Also, based on the monitoring data, the conceptual model for gas drainage process associated with different mining activities has been proposed, and few major advantages using waterjet assistance method have been identified.

Research on hydraulic slotting technology controlling coal-gas outbursts

Measured to control serious coal-gas outburst in coal seam were analyzed by theory and experimented in test site.A new technique to distress the coal-bed and drain methane,called hydraulic slotting,was described in detail,and the mechanism of hydrau- lic slotting was put forward and analyzed.The characteristic parameter of hydraulic slotting was given in Jiaozuo mining area and the characteristic of validity,adaptability and secu- rity was evaluated.The results show that the stress surrounding the strata and the gas in coal seam is released efficiently and thoroughly while new techniques are taken,as slot- ting at heading face by high pressure large diameter jet.The resistance to coal and gas outbursts is increased dramatically once the area of slotting is increased to a certain size. In the process of driving 2 000 m tunnel by hydraulic slotting excavation,coal and gas outburst never occurre.The technique could be used to prevent and control potential coal-gas outburst in the proceeding of tunnel driving,and the speed tunneling could be as high as more than 2 times.

Controlling entry in soft rock with natural support strength,strikesill,etc.

Presented the concept of the natural support strength.The natural support strength,the strike sill,the multifunction retractors (developed by the author) and etc.were used with the technical measures to change the passive support to the initiative support, and the soft rock entry was supported.And its process is simple and less equipment is needed,and the cost is low and the advance rate is high,which can meet the require- ments of actual mining.It solves many support difficult problems.

Clinical efficacy of comprehensive therapy based on traditional Chinese medicine patterns on patients with pneumoconiosis: a pilot double-blind, randomized, and placebo-controlled study

Effective therapy options for pneumoconiosis are lacking.Traditional Chinese medicine(TCM)presents a favorable prospect in the treatment of pneumoconiosis.A pilot study on TCM syndrome differentiation can evaluate the clinical efficacy and safety of TCM and lay a foundation for further clinical research.A double-blind,randomized,and placebo-controlled trial was conducted for 24 weeks,in which 96 patients with pneumoconiosis were randomly divided into the control and treatment groups.Symptomatic treatment was conducted for the two groups.The treatment group was treated with TCM syndrome differentiation,and the control group was treated with placebo.The primary outcomes were the six-minute walking distance(6MWD)and the St.George Respiratory Questionnaire(SGRQ)score.The secondary outcomes were the modified British Medical Research Council Dyspnea Scale(mMRC),Chronic Obstructive Pulmonary Disease Assessment Test(CAT),Hospital Anxiety and Depression Scale(HADS),and pulmonary function.Only 83 patients from the 96 patients with pneumoconiosis finished the study.For the primary outcome,compared with the control groups,the treatment group showed a significantly increased 6MWD(407.90 m vs.499.51 m;95%confidence interval(CI)47.25 to 135.97;P<0.001)and improved SGRQ total score(44.48 vs.25.67;95%CI 27.87 to 9.74;P<0.001).The treatment group also significantly improved compared with the control group on mMRC score(1.4 vs.0.74;95%CI 1.08 to 0.23;P=0.003),CAT score(18.40 vs.14.65;95%CI 7.07 to 0.43;P=0.027),and the total symptom score(7.90 vs.5.14;95%CI 4.40 to 1.12;P<0.001).No serious adverse events occurred.This study showed that TCM syndrome differentiation and treatment had a favorable impact on the exercise endurance and quality of life of patients with pneumoconiosis.