A friction bolt assembly to frictionally engage an internal surface of a bore formed in rock strata, the assembly comprising: an elongate tube having a leading end and a trailing end; an expander mechanism located within the tube and towards or at the leading end and configured to apply a radial expansion force to the tube to secure the assembly to the rock strata; an elongate bar or cable extending longitudinally within the tube and connected at or towards a first end to the expander mechanism and at or towards a second end to an anchor mechanism positioned at or towards the trailing end of the tube; a retainer mechanism acting between the tube and the bar or cable such that at least a length portion of the bar or cable is prevented from the ejection from the assembly should the bar or cable break; wherein the retainer mechanism comprises a restrainer positioned radially between the bar and an inner surface of the tube; the anchor mechanism comprising a fixing mountable at or towards the second end of the bar or cable and configured to brace against the trailing end of the tube that by adjustment creates tension in the bar or cable to act on the expander mechanism and create the radial expansion force; at least a part of the fixing projects radially outward beyond the tube or a component attached to an external region of the tube so as to be capable of being braced against the rock strata at a region around an external end of the bore; characterised in that: a sustainer attached at or towards the trailing end of the tube; and an engager provided at the bar or cable axially intermediate the sustainer and the first end of the bar or cable; wherein the engager is configured to engage radially the restrainer and the restrainer is configured to engage radially the sustainer to prevent the ejection of the bar or cable from the assembly should the bar or cable break; wherein the sustainer comprises a tab projecting radially inward from the tube. an elongate tube having a leading end and a trailing end; an expander mechanism located within the tube and towards or at the leading end and configured to apply a radial expansion force to the tube to secure the assembly to the rock strata; an elongate bar or cable extending longitudinally within the tube and connected at or towards a first end to the expander mechanism and at or towards a second end to an anchor mechanism positioned at or towards the trailing end of the tube; a retainer mechanism acting between the tube and the bar or cable such that at least a length portion of the bar or cable is prevented from the ejection from the assembly should the bar or cable break; wherein the retainer mechanism comprises a restrainer positioned radially between the bar and an inner surface of the tube; the anchor mechanism comprising a fixing mountable at or towards the second end of the bar or cable and configured to brace against the trailing end of the tube that by adjustment creates tension in the bar or cable to act on the expander mechanism and create the radial expansion force; at least a part of the fixing projects radially outward beyond the tube or a component attached to an external region of the tube so as to be capable of being braced against the rock strata at a region around an external end of the bore; characterised in that: a sustainer attached at or towards the trailing end of the tube; and an engager provided at the bar or cable axially intermediate the sustainer and the first end of the bar or cable; wherein the engager is configured to engage radially the restrainer and the restrainer is configured to engage radially the sustainer to prevent the ejection of the bar or cable from the assembly should the bar or cable break; wherein the sustainer comprises a tab projecting radially inward from the tube. a sustainer attached at or towards the trailing end of the tube; and an engager provided at the bar or cable axially intermediate the sustainer and the first end of the bar or cable; wherein the engager is configured to engage radially the restrainer and the restrainer is configured to engage radially the sustainer to prevent the ejection of the bar or cable from the assembly should the bar or cable break; wherein the sustainer comprises a tab projecting radially inward from the tube.