Just as coring was to get underway approximately 5 m from the ""10480"" fault zone, it was evident that there was a problem downhole with either the motor or core barrel. It was decided to trip out of the hole for inspection and replacement of the malfunctioning components. When the equipment came to the surface, it was discovered that the core barrel had detached. It is not clear how this happened as the threads were tightened to the prescribed torque prior to running in the hole, there was no reverse rotation of the drillstring and there appears to be no damage to either set of threads. Fishing is now underway to retrieve the core barrel.