First annual report for EL 26018, EL 26019, EL 26020 and EL 26021

Abstract

This report is the first annual report for ELs 26018, 26019, 26020 and 26021 located in the Barkly region of the Northern Territory. The ELs are prospective for phosphate and uranium. The following exploration activities were carried out during the reporting year: 1)Office-based: desktop studies to identify targets; a regional assessment and development of exploration models; and an internal review of historical drilling and phosphate mineralisation in the region. 2)Field-based: reconnaissance sampling program to examine targets and collect geochemical samples. The desktop study revealed 35 targets, 33 of which were sampled during the field reconnaissance program. The reconnaissance report concluded that the work completed failed to identify any obvious signs of mineralisation. This is also borne out in the geochemical sampling results. The regional assessment resulted in the recognition of several parameters considered to be important in the exploration for phosphate mineralisation. The internal study to review historical drilling and phosphate mineralisation in the region indicates that the depth to the top of the phosphate horizon is shallower on the northern ELs and the chances of finding outcropping beds close to the Pre-Cambrian basin boundary are higher than the southern ELs. An initial desktop review of GIS datasets covering ELs 26018-21 recognised 35 target localities based upon combinations of radiometrics, magnetics, gravity and digital terrain modeling (DTM). Follow-up field inspection did not confirm the presence of significant phosphate or uranium mineralisation at these locations (CSA Global - Report 259.2008). A subsequent review of the results obtained, in the context of modeling phosphate prospectivity, has determined that the southern tenement areas, ELs 26020 and 26021, contain stratigraphic equivalents of the Mid-Cambrian Wonorah Beds and Camooweal Dolomite that are known to host phosphate deposits (CSA Global - Report 275.2008). An internal project review completed by Mantle Mining Corporation (Hornabrook, 2008) considered historical phosphate exploration programmes with particular attention to historical drilling data and compilation of a common stratigraphy across Mantle's tenement areas. This review concluded that prospective phosphatic stratigraphy is likely to be present at sub-economic depths within the southern tenements ELs 26020 and 26021. However, the northern tenements EL 26018 and the western part of EL 26019 are also recognised as containing demonstrated phosphatic stratigraphy at shallow depths. It is suggested that the 2009 work programme focuses on a series of subsurface embayments within EL 26018, and the potential projection of the subsurface ridge that hosts the Alexandria deposit into EL 26019; which are considered to be favourable loci for deposition of economic accumulations of phosphate.