Due to the strong impacts or rockbursts in Ostrava-Karvina coalfield, which affect especially roadways and cross-cuts of longwall panels, it is necessary to strengthen standard steel roadways and breakthroughs supports. However it is a little different task in comparison with main solved problems of mining safety (Kidybinski, 2011), the use of reinforcing complementary bolts seems to be very effective. A varieties of numbers and locations of such rockbolts have been analyzed and compared from the viewpoint of the stability under dynamic events on the base of 3D mathematic modeling. The method used for computer modeling has been FEM applied by ANSYS code. It deals with the shape and nature the following issues: the deformation of a steel support, strain and deformation of reinforcing bolts, the critical energy by which a permanent strain is caused and the influential interaction of the adjacent rock on the above mentioned characteristics. A recommendation for number and location of reinforcing complementary bolts is also contained.