A rotary drilling rig includes a vertical mast and a rotary head that can vertically move along the mast with respect to a work surface. To move the rotary head along the mast, a hydraulic feed actuator is connected with the rotary head via a wire rope feed system including a hoist rope and a pulldown rope. To maintain the hoist and pulldown ropes in tension and prevent them from dislodging from the respective pulleys of the wire rope system, the hoist and pulldown ropes can be connected to respective hoist and pulldown tensioning actuators. The hoist actuator can be associated with a hoist hydraulic circuit and the pulldown tensioning actuator can be associated with a separate pulldown hydraulic circuit.