Abstract: A conveyor assembly includes a plurality of idler pulleys over which a belt rolls. The idler pulleys are journaled in bearings in side walls of the conveyor assembly. The pulley includes a generally cylindrical center portion or shaft and a stub shaft that is removably mounted to end walls at each end of the pulley shaft. Each stub shaft has a radially disposed flange that is used to removably secure to the stub shaft to the pulley shaft. Additionally, at least one of the bearings for each idler pulley is mounted in an access panel. The access panel is removably mounted to the conveyor side wall and is sized and shaped, such that when they are removed from the conveyor side wall, the pulley stub shaft can be easily reached in order to be removed from the pulley, and the pulley itself can be easily removed from the conveyor, for repair or replacement.

Abstract: The present invention is directed to sonic logging while drilling. A transmitter and at least one receiver are mounted on a drill collar for performing sonic investigations of the formation traversing a borehole. It has been discovered that a drill collar has a natural stop band or notch where acoustic energy propagating in this frequency range is severely attenuated. Thus, to reduce drill collar acoustic coupling, the transmitter is operated within this natural stop band of the drill collar. An imperforate stop band filter is also included between the transmitter and receiver to amplify the natural stop band. The transmitter is mounted transvere to the longitudinal axis of the drill collar, and is preferably mounted within means that reduce drill collar acoustic coupling.

Abstract: The present invention is directed to sonic logging while drilling. A transmitter and at least one receiver are mounted on a drill collar for performing sonic investigations of the formation traversed by a borehole. It has been discovered that a drill collar has a natural stop band or notch where acoustic energy propagating in this frequency range is severely attenuated. Thus, to reduce drill collar acoustic coupling, the transmitter is operated within this natural stop band of the drill collar. An imperforate stop band filter is also included between the transmitter and receiver to enhance the natural stop band. The transmitter is mounted transverse to the longitudinal axis of the drill collar, and is preferably mounted within means that reduce drill collar acoustic coupling.