After BHP Billiton (BHPB) gained ownership of two of the subject exploration licences, and later was granted another three in its own right, the licence group as a whole (now called the Lake Torrens Project) continued to be explored primarily for possible economic Olympic Dam style IOCG mineralisation hosted by the concealed Mesoproterozoic basement. No on-ground field work occurred during Year 1 of the project, pending establishment of productive dialogue with the local Native title claimants for the subject areas, but a Falcon airborne gravity survey was flown during June 2013 over the southern licence Burt Lagoon EL 4762, for 729 line km of coverage along north-south flight lines spaced 600 m apart, using a mean sensor elevation of 60 m above the ground surface (nominal terrain clearance). A desktop study of all available data was also undertaken by BHPB to identify potential IOCG targets, and several high and low priority targets were identified, including the main one which straddles the Torrens Hinge Zone on EL 4762 in an area of inferred geological complexity. No on-ground field work was planned or undertaken during Year 2 of the project, and no contact for the purpose of obtaining Aboriginal heritage clearances was made with any of the five Native Title claimant groups that lay claim to parts of the project acreage. BHP Billiton continued to assess and interpret the data from the 2013 Falcon airborne gravity gradiometer survey, utilising both forward and inversion modelling methods, besides re-interpreting other available (geophysical) datasets and the limited amount of available drilling data to construct geological models of possible mineralisation. Forward modelling was performed in May 2014 by Jim Hanneson from Adelaide Mining Geophysics, and inverse modelling was completed in May 2014 by CGG Aviation to create a 2D model estimating depth to top of gravity source body / dense ?haematite-rich target. Due to the perceived low geological prospectivity of the northern Lake Torrens ELs 5004 and 5005, these were surrendered during the year. During Year 3 of the project, BHP Billiton commissioned forward geophysical modelling of a small gravity target located in the northern part of EL 4762 which Minotaur Exploration had identified. Jim Hanneson concluded from his model results that the gravity source bodies with parameters which fit the data might not be dense enough to comprise a compelling IOCG target, while the magnetic basement depth there is likely to be of the order of 800 m to 1 km. On 5/2/2015, BHP Billiton submitted to DSD an application to fully surrender all three remaining project licences.