A drill rod clamping system for securing a drill rod in a selected position. The drill rod clamping system has a hollow spindle with an upper portion that defines axial slots and a base portion that defines at least one radial opening. A plurality of jaws are moveable radially inwardly to a drill rod gripping position and radially outwardly to a drill rod releasing position. Each jaw is received within a respective axial slot of the hollow spindle. An actuator moves the plurality of jaws between the drill rod gripping position and the drill rod releasing position. A compressed gas spring assembly exerts force on the actuator to close the jaws. A hydraulic operator exerts force on the actuator to overcome the force of the compressed gas spring assembly to open the jaws. The radial openings of the base portion of the spindle permit flushing of material flowing within the spindle.