In this final report (Contract No. G0122066) experimental results are presented for specimens from the climax and Henderson Mines in Colorado and from the San Manuel Mine in Arizona. Conclusions are that some relation appears to exist between compressive strength and the following properties and features for all specimens: dynamic young's modulus, sonic velocity, density, rock composition, slope of velocity curve, composition and fabric of fracture fillings, veinlets, and apparent porosity. There appears to be some relation between compressive strength and shore scleroscope hardness for the quartz monzonite (San Manuel). A relation appears to exist between texture and compressive strength and the extent of failure on fracture fillings for schists, gneiss, and fine-grained granite (climax).