A sanding block holds a continuous loop sanding belt tightly thereon. The derivatives are obtained by utilizing a heating, extracting and condensing system that efficiently recovers the derivatives from a raw material. A bit line is connected to the drain of the reading transistor at one end thereof. The signal strength of the locating signal is then measured at the field defined forward point as being representative of the depth of the boring tool at an inground upstream point which is the current location of the boring tool. The MAH-g-LLDPE has a unique combination of properties including a low density and a high melt index.