ASX-listed Mozambique focused heavy mineral sands project developer MRG Metals has revealed that an ongoing aircore drilling campaign has defined 20 km² of high grade heavy mineral sands at its 100% owned Koko Masava project.

The large, high grade Koko Masava heavy mineral sands target has been generated from a combination of wide spaced historic drilling results and confirmed more recently by excellent auger drill results by MRG’s team.

The aircore rig arrived on site 24 September 2019 and commenced drilling on 25 September 2019. The drill programme is still underway and will conclude in late November.

Phase 1 drilling of wide spaced holes at 500 m x 1 000 m commenced in the north-east and progressed systematically along drill lines to the south-west to completion.

Spacing was established from comparison with similar, world-class heavy mineral sand deposits, including Mutamba, with the anticipation that data will meet geological confidence requirements to establish a maiden JORC mineral resource estimate for the area.

At the time of this announcement, 48 Phase 1 aircore holes had been completed comprising ~2 439 m of drilling. Hole depth varies from 24 m to 75 m, with an average of 50.8 m.

Total heavy mineral highlights

46 of the 48 holes in Phase 1 have intersected individual 3 m sample intervals of >4% estimated visual THM, with 29 of the 48 showing uncut, average estimated visual THM% grades >3% over the entire hole depth. Maximum individual sample intervals in the holes completed range from 2.9% – 13% estimated visual THM.

The best result reported is 19CCAC146 which drilled to 24 m depth and contains 24 m @ 4.64% estimated visual THM from surface, including 9 m @ 5.2% estimated visual THM (15 – 24 m). The hole ended at 24 m due to problems with sample recovery. However, the final sample interval of 21 – 24 m contained grade of 7% visual estimated THM.

These extremely encouraging results underpin MRG’s decision to immediately commence a Phase 2 infill drilling in areas of highest estimated visual heavy mineral grade with holes located at 250 m x 1 000 m and 500 m x 500 m centres.

The host lithology is typically red-brown, moderately to well sorted, medium grained sand with moderate silt content. Estimated visual THM grades at the project typically range between 1% – 6% from surface to around 18 m.

In hole grades below 18 m commonly range 3.5% – 8% estimated visual THM. The highest estimated visual THM grades (i.e. 10 – 13%) appear to be located between 21 – 33 m downhole, suggesting potential palaeo-strandline in the tested zone.

The first batch of aircore samples has been fully permitted by the Ministry of Mineral Resources with final Customs clearance underway and is anticipated to arrive in Perth in the week beginning 18 November 2019.

The third batch of auger sample laboratory results are expected to be delivered by 15 November 2019, with results to be reported shortly after.

“This phase of drilling has unlocked a large, high grade area at Koko Masava and the grade we are witnessing at and near surface is a major tick for MRG. We are now progressing with infill drilling to better define this large target and we are focused on the areas, which delivered the highest estimated visual heavy mineral grade,” says chairman Andrew Van Der Zwan. 

“Koko Masava is shaping up to be another one of Mozambique’s large heavy mineral sands projects and we are only at the early stages of our exploration initiatives.”