Abstract: A yieldable grout compactor for a cable roof support fixture adapted to be insertable in a uniform diameter borehole or in a stepped borehole in which the grout cartridge and compactor are insertable so as to have the cable perform the piercing and mixing function with respect to the grout material while the compactor is slidable on the cable caused by a sufficient degree of force to permit the grout to surround and anchor the cable. Compactor sleeves are sized with respect to the axial cable length and the internal and external diameters are sized to yieldably permit fixture installation and grout securement of the cable in a manner to obtain a secure anchor for the cable in the back of the borehole.