The application of cable bolts in underground mines is an increasing trend all over the world; therefore, it is necessary to determine the axial and shear stresses on cable bolts. One important factor is to determine the coefficient of friction of concrete joint surface. This paper examines the contact coefficient of several cabled strata under various pre-tension loads subject to double shearing test. The result shows that the contact surface area can vary between 70-90% of the total surface area. This empirical value helps to figure out shear and axial stresses, where it is impossible to determine the exact amount of contact coefficient.