LIT Glue And Its Application In Increasing Gas Suction

Coalbed gas was generated with coal, and its main ingredient is CH₄. Recovering a higher proportion of the deposited gas before coal mining is an effective way to prevent gasbrusts, reduce metane emission and enhance the mining efficiency. One of the key reasons why most of coal mines have a coalbed gas recovery lower than 20% is the poor sealing of the production wells. Traditional sealing techniques have focused on sealing of the wells itself, the effect of which has been proven poor by practical experiences. In fact, sealing the cracks surrounding the well should be as important as sealing the well itself. Based on this point, the author has developed a glue, named LIT. The cracks are sealed by spraying the glue onto the walls of a coal tunnel. The glue can be solidified when contacting air, formed into membrane-like materials, prevent air from entering the coalbed, help to maintain a higher suction pressure in the well, and eventually enhance the gas recovery ratio. The more the gas is produced and transported to surface via a piprline, the lower the methane concentration of the ventilation air in the tunnel will be. The purpose of this study is to develop the materials, apparatuses and procedures suitable for coal tunnel sealing..Chapter 1 describes the relevant background.Chapter 2 presents a brief description of the tun nel sealing method.Chapter 3 is about the laboratory experimental research on LIT glue. The results showed that the glue is suitable for the tunnel sealing.Chapter 4 goes to tunnel sealing tests in a coal mine. The walls of q 200m long tunnel was covered with LIT, and the gas production processes, before and after the sealing, was monitored. The results showed that the sealing has a remarkable role in enhance the gas production rate and concentration.Chapter 5 discusses the role of the sealing in reducing the methane concentration in tunnel ventilation air.Chapter 6 outlines major conclusions and the further work.