The 3D lattice Boltzmann (LB) method was used to model mixing at three types of continuous fracture intersections: planar, fluted (containing parallel grooves), and rough-walled. Peclet number (Pe) varied from 3 to 400, and Reynolds number (Re) varied from 0.5 to 100. In both planar-and rough-walled intersections, the mixing ratio (Mr) decreases with increasing Pe, though the decrease is less dramatic for the rough-walled geometry. In planar-walled intersections, the Mr decreases with increasing Re; however, the fluted and rough-walled intersections show the opposite trend. Overall, the impact of inertial effects is slight for Re ≤ 10. The effects of channel length are also small; the calculated Mr varies little for LB simulations with length/width ≥ 1. ¿ 2001 American Geophysical Union