Abstract: A surgical navigation method utilizing a computer system. The method includes the steps of: (a) fixing a camera relative to a surgical site on a patient such that the camera does not move relative to the surgical site; (b) restraining the body portion of the patient which includes the surgical site relative to an operating table supporting the patient, such that the body portion does not move relative to the operating table; and (c) detecting with the camera the position of a medical instrument having a tracker array.

Abstract: A tractor rake attachment is disclosed that includes a rake platform, the rake platform having a plurality of tines secured to a rake platform with the tines having a length that extend perpendicular to the rake platform. The tines are approximately evenly spaced along the length of the rake platform and have a depth that permits elastic deformation of the tine when contacted by ta heavy rock. The tines on the rake platform may be forwardly adjusted to create a angle along the rake platform in relation to the movement of a tractor rake. The rake platform is capable of being attached to a tractor rake so that the horizontal length of the tractor rake is extended with the tines extending in a downward direction from the rake platform to the ground. A method for light and medium field grading also is disclosed.