Convergence behaviour — packing relations of full extraction gate roadways at OAL lignite mine

CIM Bulletin, Vol. 90, No. 1014, 1997

Y.S. Istanbulluoglu, Turkish Coal Enterprises, OAL Mine, Turkey, and C. Karpuz, Mining Engineering Department, Middle East Technical University, Ankara, Turkey

This paper describes the results of convergence measurements conducted about five years for the re-use gate roadways at OAL lignite mine in Turkey. Double lignite seams separated with a marn layer, are mined with longwall retreating mining system at the mine. Rib pillar has been abandoned and gate roadways were planned to be packed for the re-use of full extraction. Various packing systems have been attempted, namely three rows of wooden chock, one row of wooden chock plus concrete wall and concrete wall only. The re-use of main gate roadways packed with wooden chock yielded 62% of closure. Lastly developed concrete packing of 3 meters wide and specially developed support set composed of three friction props and a cap, which is a modification of yieldable set, have successfully maintained the main and tail gate roadways stability with a total vertical convergence of 32%. Good correlation has been established between pack stiffness and floor heave as well as maingate and tailgate convergences. The elimination of rib pillars by re-use of gate roadways increased the coal recovery by 20% and decreased the development/ production ratio from 0.065 m3/ton to 0.022 m3/ton
Mots Clés: Rock mechanics, Gate roadways, Coal recovery, Packing.