Adjustable grade stick and method of using same

Abstract

An adjustable grade stick and method of using the same are used to identify a reference line. The grade stick has a shaft that is adjustable along its length. In a preferred embodiment, the shaft has two sections where one section lies within the other in a variably telescoping manner. A locking device is provided to lock the relative positions of the first and second sections of the shaft. A hook is located at one end of the shaft to mount the shaft on the ceiling of the mine tunnel. A sighting ring is located at the other end of the shaft and has an inner aperture which acts as a marker for a reference point. A calibration scale is located on the shaft for positioning the sighting means at a predetermined location. The reference line is sighted from the sighting rings of a pair of grade sticks. A method of using the grade sticks consists of taking a pair of the adjustable grade sticks, adjusting their lengths to predetermined settings, mounting the grade sticks on the ceiling of a mine tunnel at predetermined locations and aligning the sighting rings on each shaft to form a reference line which is used to guide drilling operations within the mine.

Dependencies are inferred from the claim text.