Techno-Economic Analysis Of Grouting Reinforcement Project About 11 Coal Seam Floor In Qiuji Coal Mine

Coal resource is one of the most important energy sources in China.The risk of water inrush from coal floor threatens the safety of coal mining.Therefore,it has a practical significance to study the treatment of floor water inrush.In recent years,with the continuous development of drilling technology,the surface directional drilling technology has gradually begun to be used in the coal mine floor grouting transformation,which is a new technology for the floor grouting transformation of the face threatened by water in China.This article mainly studies the floor grouting reinforcement of 11 coal seam in Qiuji coal mine,which uses the technical and economic analysis method.This paper draws the following conclusions.Based on the detailed analysis of the geological structure and hydrogeological conditions of 11 coal seam,it calculates the water inrush coefficient of the limestone which is 0.12 MPa/m.It exceeds the minimum safety value of 0.1MPa/m.It also calculates the safety head value.The resultis 2.1 MPa,which is obviously lower than the measured water pressure of 4.1 MPa.It means that there is a serious risk of water inrush of 11 coal seam.It is necessary to carry out grouting reinforcement of the bottom plate.This article constructs the technical analysis indexes of coal seam floor grouting reinforcement project,which includes scheme selection,injection layer selection,the layout of drill field and borehole,grouting materials,construction technology and safety measures.Delphi method is used to analyze the scheme selection.It establish the evaluation standards of injection layer determination and the layout of drill field and borehole.It analyzes the grouting materials,construction technology and safety measures in detail.Through the analysis,it shows that the high pressure grouting scheme is reasonable and technically feasible for the 11 coal grouting reinforcement project of Qiuji coal mine.The economic evaluation of the project is carried out by using NPV,IRR and payback period methods.The calculation of NPV and IRR shows that the project has strong profitability.The dynamic payback period method is used to analyze the risk of capital recovery.The conclusion shows that the project can recover the investment capital in a short time.Through the break-even analysis,the utilization rate of project capacity is calculated.It calculates the price and cost by The sensitivity analysis method.It shows that the capacity of the project is sufficient.It has strong ability to resist risks.It constructed the evaluation index system of technical and economic effects,which including three technical indicators,three economic indicators and two social indicators.The indicators include internal rate of return,dynamic investment recovery period and tonnage cost,the selection of injection layer,construction quality and advanced technology,the social evaluation and environmental impact.The main method is analytic hierarchy process.Firstly,it constructed the primary and secondary indexes of the judgment matrix.Then it calculates the weight vector and the weight of secondary indexes.Then it invites Experts to score.The evaluation results show that the high-pressure grouting technology is feasible in technology and reasonable in economy,which can play a good role in grouting reinforcement of coal mine.