Ann: Lab Results Confirm Kimberlite Target Areas, page-204

A gravity survey is a completely new look at the area from a different perspective.
The L259 kimberlite did not show up on the aerial EM survey so the gravity survey will be a fresh look at it. As it is quite large (1km apart positive trenching samples), the gravity survey may show that it consists of 2 separate kimberlites. Kimberlites tend to erupt in clusters and there is the possibility that new kimberlite anomalies are found within the survey areas which are quite large. Check the 23 November 2015 announcement and it shows the surrounding areas are also included.