Abstract: A support assembly for a mine roof, or the like, including a bolt carrying a support plate for engagement with the roof surface, an internally threaded cylindrical collar, and an elongated bar. The bar and bolt are threaded into opposite ends of the collar, the bar being threaded to a fixed stop and the bolt being threaded to a deformation at an intermediate point along the length of the collar threads. A conventional resin package is inserted in the bore hole and the assembly inserted behind it with the end of the bar contacting the package to effect rupturing thereof and mixing of the contents. Rotation of the bolt is transmitted through the collar to the bar as the resin components are mixed due to engagement of the bolt with the deformation in the collar threads. After the resin has hardened the bar and collar cannot be further rotated.