... used to relieve the stress as well as to pre-condition the dolerite above the following two panels. The shortwall on the N° 2 Seam has experienced mid-face loading due to N° 4 Seam chain pillars lying over this area and creating a secondary cantilever effect. Pre-split blasting of the solid rock above...

... ABSTRACT The use of coal pillars at depth is fraught with problems due roof control difficulties and the possible occurrence of coal or pillar bumps. In the USA the largest and most important application of pillars at depth is in longwalling, where chain pillars are the customary supports...

... under the profiles, the integrity factor is proposed here as a rational parameter for evaluating chain-pillar stability. RESUME: Les profils des charges causees par l'exploitation minière, ainsi que les profils des resistances residuelles au travers des piliers varient avec la positfon du "longwall...