An improved mine roof bolt is disclosed. The mine roof bolt comprises a bolt portion having a threaded end, a slidable camming nut, a stop, and an expansion shell having a central threaded nut with wedge fingers extending from it. The camming nut is fitted into the expansion shell which is threaded onto the threaded section of the bolt. Turning the bolt while it is in a hole causes the expansion shell to move along the bolt and carry the camming nut to the stop located on the bolt, and this causes the wedge fingers to engage with the camming nut, spreading the wedge fingers into contact with the hole sides. As the turning of the bolt continues, the relative movement of the camming nut and wedge fingers increases the wedging effect within the hole until the bolt is anchored in the hole. While turning of the bolt may serve to mix a catalytic adhesive, the adhesive is not needed to activate the mechanical anchoring mechanism of the mine roof bolt.