Following the process defined by the CHA, Diatreme assisted with a Cultural Heritage survey in August 2017 over the proposed reconnaissance exploration area in the Nob Point to Elim Beach area in the southern part of EPM17795. A reconnaissance exploration program was subsequently approved, and Diatreme commenced exploration in September 2017 utilising a Company-owned and operated air-core drilling rig.
Reconnaissance drilling was planned alongside established roads and tracks, with line clearing and reconnaissance drilling also planned over a dune system in the southern part of the EPM.
The exploration program was developed based upon encouraging results from historical exploration in the 1970’s and 1980’s (although this was itself reconnaissance in nature), encouraging observations from Diatreme’s site visits, and the ease of access due to several roads and tracks traversing the area.
During September 2017, 29 holes were drilled along Elim Road and a related beach access track, for a total of 606m with an average hole depth of 21m. The logged geology was reasonably consistent in defining large areas of fine grained quartz sand, but sand colour was variable, with a variety of coloured sands particularly apparent towards Elim Beach.
This is not surprising, as Elim Beach itself is known for its exposures of eroded high dune cliffs displaying “coloured sands”. Widespread, but low-grade HM mineralisation was observed in most of the roadside reconnaissance drilling. The beach access track runs alongside a broad elongate swamp, and holes drilled here encountered quartz sands with a shallow water table (~3m) and typically white sands on surface and tannin stained light brown to brown sands below water table.
Holes drilled along the central part of the Elim Road returned good thicknesses of fine grained white quartz sands from surface, and assay results support the logging with an average 99% SiO2 reported for the samples submitted for analysis.
A table of summary XRF assay results from the September 2017 drilling is presented below:
The assay results are considered highly encouraging in light of the fact they are as-drilled samples, with no sample preparation (e.g. washing, HM removal) as would typically be carried out for silica sands. Minor amounts of HM (ilmenite dominant) were observed during logging, as evidenced by the iron and titanium assay results reported.
Widespread, but low-grade HM mineralisation was observed in most of the roadside reconnaissance drilling, with a visual estimate of background HM grades averaging around 0.3% for the drilled areas.
However, some holes showed higher levels of HM in visual logging, and 60 samples were submitted for HM analysis to assess the economic potential of the observed HM.
Significant results are shown below:
The HM mineralisation observed to date confirms the presence of HM in the region and the potential of the area to host mineralisation, but is not considered to be economically significant within the area currently being explored.
During October, 26 holes were drilled along cleared access tracks over a dune complex near Nob Point, for a total of 670m with an average hole depth of 26m. The logged geology was reasonably consistent in defining large areas of fine grained quartz sand, but sand colour was variable throughout the drilled area of the dune system, suggesting a complex depositional (and erosional) history for the dune complex.
Several large zones of white, fine grained quartz sand extending over 400m in length along the dune ridges were evident from surface down to 30m depth, and although these do not form a continuous body of white sand along the entire length of the dune ridges that were drilled, they do have potential to represent a body of sand with sufficient size that may allow large scale sand extraction for commercial purposes.
A table of summary XRF assay results from the October 2017 drilling is presented below:
The assay results are considered encouraging given they are as-drilled samples, with no sample preparation (e.g. washing, HM removal) as would typically be carried out during silica sands processing.
The reconnaissance air-core drilling has allowed a general understanding of the dune geology, and returned results that confirm both the exploration potential of a significant silica sand deposit in the area, together with more localised occurrences of HM mineralisation.
Bulk samples of approximately 100kg each from six separate drill holes were submitted for preliminary metallurgical testwork to assess the potential to generate a high-quality silica sand product from the white quartz sands intersected from the October drilling program.
Technical information relating to the reconnaissance exploration program is available in the ASX announcement released 31 January 2018. Positive testwork results were announced to the ASX on 2 March 2018.