A turbine rotor blade with a serpentine flow cooling circuit, especially a blade with a wide open tip turn, where the tip turn includes a main rib separating the two legs that are connected to the tip turn and include a bleed cooling air hole with a mini rib formed along side the main rib in the downstream leg from the tip turn in which bleed cooling air from the upstream leg flows through the hole and is impinged onto the mini rib. The bleed cooling air not only provides additional cooling for the tip turn region of the blade but eliminates the separation and recirculation issues creates in tip turns of the prior art. The bleed cooling air hole and mini rib can also be used in the root turn.