Feasibility Study on Upward Mining in Seam Group with Short Distance to Each Other in Kailuan Mining Area

In order to adjudge the feasibility of the upward mining in the seam group with a short distance to each other, base on the about 20 years upward mining cases, the evaluation index of the upward mining was set up and was quantified.When the mining operation in the lower seam completed, the failure degrees affected to the up seam were divided into five grades.The higher of the failure grade, the more difficult the upward mining would be. Base on the circumstances, taking the initial fall ing step distance of the direct roof, the time interval and the mining influence coefficient as the independent variable and taking the failure degree of the up seam as the dependent variable, the adjudgement of upward mining feasibility in the seam group with a short distance to each other was established.The results showed that the hig her of the mining influence coefficient, the longer the time interval between the up seam mining and the low seam mining would be favorable to the up seam mining.