Key technology of directional grouting in roof and floor of coal field in the north of the Yellow River

In order to effectively solve the double water hazard problem of the roof and floor aquifer in the coalfield of the north of the Yellow River, we takes the treatment of water disaster in Shandong Energy Qiuji Coal Mine as an example, which based on the analysis of mine hydrogeology and water disaster characteristics, determines the concept of water control in advance, regional coordination, grouting where water leakage occurs and safety promotion. We put forward the technology of limestone water disaster control with “roof and floor injection and curtain grouting”. The “plum blossom” and “upper and lower strata penetration” drilling methods are used to effectively explore karst fissures and concealed water channel in aquifers, and through the real-time observation technology of equidistant directional drilling and hydrogeology borehole to ensure the precise grouting. By the end of 2018, 19 main holes and 95 branch holes were constructed in the grouting project, which accumulated 64 183.74 meters, 329 035 tons of cement and 24 845 tons of coal ash. The results showed that the water pressure of limestone decreased obviously after grouting and gushing water volume was less than 10 cubic meters per hour, which achieved the safety exposing and pilot production in coalface. It is pointed out that the key technology of directional grouting in the north of the Yellow River coalfield can effectively seal karst fissure and concealed water channel in aquifers and achieve high quality precision grouting for karst fissure and water channel of aquifers. This technology provides safety guarantee for the two hundred million tons of coal of the lower coal group, and also provides reference for the prevention and control of similar water disasters in the north of the Yellow River coalfield of China.resources