There may be considerable upside to Middle Island Resources’ lowish grade Two Mile Hill gold deposit at the company’s Sandstone project in Western Australia with diamond drilling intersecting high grade gold recently.
The new notable interval was 8 metres long grading an impressive 14.5 grams per tonne gold from 334 metres including 2m at a very significant 54g/t gold intersected in the sparsely drilled middle banded iron formation.
This style of mineralisation adds to the more substantial, but lower grade, adjacent tonalite-hosted mineralisation which is essentially a 700m deep vertical mineralised plug going around 1.1 grams per tonne or slightly higher
The tonalite plug is cross cut by a number of banded iron formations and Middle Island have long held the view that these banded iron formations may well contain high grade gold – a theory that now appears to be well founded.
The company said the distribution of higher grade banded iron formation intercepts encountered to date suggests the mineralisation comprises a semi-continuous annulus that developed immediately peripheral to the tonalite contact, within both the upper and middle banded iron formations while the lower formation is yet to be drilled.
The intercept marks the first time that significant gold mineralisation has been identified within brecciated elements of the stacked banded iron formations at Two Mile Hill.
Middle Island Managing Director Rick Yeates said: “Although only a secondary objective of the resource definition drilling, it is extremely pleasing to identify such a strong, higher grade gold intercept of BIF-hosted mineralisation in the very first hole of the program.”
“It is also extremely encouraging to identify a further example of this style of mineralisation within the middle BIF unit, as the majority of previous intercepts have been in the more extensively drilled, upper BIF unit.”
The recently completed drilling campaign is focused on the upper half of the Two Mile Hill tonalite deeps deposit and was designed to infill the existing drilling.
It was also intended to generate the maximum number of intersections on the adjacent banded iron formations that are known to host high grade, pyrite replacement style gold mineralisation.
At Two Mile Hill, more than 96% of the gold mineralisation is hosted in quartz veining within a barren tonalite.
The tonalite plug is 250m long and 80-90m wide at surface and located 4km north of the Middle Island’s 600,000tpa Sandstone gold processing plant via an existing haul road.
Last month, the company said it can increase gold head grades at Sandstone by between 155% and 213% by using a simple “ore sorting” method to weed out more waste rock from the mineralised rock.
Middle Island’s second stage ore sorting investigative campaign has already demonstrated that Two Mile Hill ore can be significantly upgraded via a combination of optical colour scanning and X-raying, potentially enhancing the economics of the project.
The new banded iron formation high grade hits places a different complexion on Middle Island’s Sandstone project and might just provide some excitement for shareholders as the company drills out the other banded iron formations at the project.
