The present invention relates to novel methods for monitoring or tracing a job operation performed in a borehole, such as well boreholes traversing a geological formation. In one embodiment, the novel methods of the invention comprise the steps of: (a) disposing into the borehole a neutron absorber during the performance of the job operation; (b) logging the borehole with an instrument capable of measuring a neutron capture in and around the borehole after performance of the job operation; and (c) monitoring or tracing the job operation performed in the borehole by comparing the measured neutron capture with a baseline neutron capture in and around the borehole. The methods of the present invention pose small or no risk from a health safety and environment perspective and are useful for monitoring or tracing hydraulic fracturing, cementing operation in well boreholes, production logging or subsurface location of downhole collars, float shoes and other jewellry.