The McCalls project is located 110km to the north of Perth near the town of Gingin. Previous exploration by BHP in the early 1990s outlined large, low grade (1.0 -1.5% HM) heavy mineral sand deposit covering an area of 30km2, and extending from near-surface to depths of typically 30-45m. Further drilling by Sheffield shows the mineralisation is up to 60m thick, with an average overburden thickness of 6m.
In the June 2018 quarter, work commenced on an update of the McCalls Mineral Resource to include additional historic drilling data from the recently granted Exploration Licence E70/4922, which adjoins the current Mineral Resource area.
McCalls currently has a Mineral Resource (at a 1.1% HM cut-off) of 3.65Bt @ 1.4% HM (Indicated and Inferred) for 50.4million tonnes of contained HM comprising 39 million tonnes of chloride ilmenite (59% to 66% TiO2), 2.5 million tonnes of zircon, 1.6 million tonnes of rutile and 1.5 million tonnes of leucoxene (see Quarterly Activities Report for the Period Ended 30 June 2016 - released 25 July 2016).
The mineral assemblage has a high valuable heavy mineral (VHM) component of 89.7%, comprising 78.5% ilmenite, 5.1% zircon, 3.2% rutile and 2.9% leucoxene.
Ilmenite characterisation studies on Sheffield’s drill samples produced concentrates containing between 59% and 66% TiO2, indicating potential suitability for chloride-route or synthetic rutile processing (see ASX release 27 October 2011). The work also demonstrated the heavy mineral is well suited to conventional mineral processing methods. Significantly, the McCalls deposit contains 39 million tonnes of chloride grade ilmenite, ranking it as one of the largest accumulations of chloride grade ilmenite in the world.
The McCalls project is well situated with respect to existing infrastructure, including main roads, rail and power. A railway line is situated 10km to the east of the project and connects to Fremantle/Kwinana ports approximately 160km to the south.
20km to the south of the McCalls deposit is another large mineral sands occurrence known as Mindarra Springs. Sheffield’s geologists have outlined an Exploration Target1 of 1.7-2.2Bt at 1.4%-1.6% HM for Mindarra Springs, based on drilling undertaken by BHP in the early 1990s (refer to September 2014 Quarterly Report for full details). Limited data indicates a mineral assemblage similar to that of the McCalls deposit.
1Sheffield Resources has not yet reported any Mineral Resources for Mindarra Springs and any discussion in relation to the potential quantity of the targets is conceptual in nature. There has been insufficient exploration to define a Mineral Resource and it is uncertain if further exploration will result in the determination of a Mineral Resource.