What was found
(CAN) PILOTS LOADED PAX DEPARTED THE GATE. AFTER RECEIVING TAXI CLEARANCE THE PILOT NOTICED THE RIGHT LOW OIL PRESSURE WARNING LIGHT,THE AIRCRAFT WAS TURNED AROUND AND THE ENGINE SHUTDOWN. THE AIRCRAFT RETURNED TO THE GATE AND THE PASSENGERS UNLOADED. THE AIRCRAFT WAS TOWED BACK TO THE MAINTENANCE HANGER AND INSPECTED. WHEN THE OIL FILTER WAS REMOVED THERE WAS A LARGE AMOUNT OF SILVER COLORED MAGNETIC PARTICLES IN THE FILTER. THE ENGINE HAS BEEN REMOVED AND WILL BE SENT BACK TO MFG FOR INSPECTION/OVERHAUL, (TC NR 20070330005)