Lithium exploration and project development company Critical Resources Limited’s (ASX:CRR) follow-up drilling around the recent breakthrough discovery intercept has continued to validate and expand the recently discovered “Swell Zone” at the Mavis Lake Lithium Project in Ontario, Canada.
Since that discovery intercept, the company has completed a series of further drill-holes targeting this exciting new position, with multiple holes encountering thick mineralised intercepts, demonstrating consistency around the plunge theory at the Mavis Lake Main Zone.
Current drilling forms part of the summer 2023 resource extension drilling programme, seeking to establish Mavis Lake as the largest single-site, JORC Code 2012 Compliant Lithium Resource in Ontario.
Extension of Swell Plunge Trend
The drilling was designed to follow up the successful intercept in Drill-hole MF23-207 and test both the lateral, up-dip and down-dip extents of the newly identified Swell Zone.
Drill-hole MF23-208 was immediately drilled following the success of MF23-207, however this hole was originally designed for resource extension and intersected the Main Zone up-dip of the swell trend.
The hole was able to intersect three significant mineralised zones, with multiple high-grade sections over 2.2% Li2O. The drill-hole also demonstrated continuity, with two intercepts of continuous, high- grade mineralisation, each over 13 metres down-hole grading over 1.5% Li2O.
The deepest zone, starting at 343m down- hole, demonstrates the presence of significant spodumene mineralisation at depth, which will continue to be tested.
Drill-holes MF23-209 and MF23-210 were designed to test the down-dip extents of the swell trend identified by MF23-207. Both returned multiple thick intercepts of high-grade spodumene, including exceptionally high-grade zones grading over 3% Li2O. Some mineralised segments were separated by very thin mafic volcanic units.
These intercepts have extended the mineralisation in the Swell Zone by an additional ~50m down- dip and ~25m east. These holes were also used to assist in defining the geometry of the Swell Zone and allow for future drill-hole planning.
MF23-211 was a step-out, collared west of MF23-207 and designed to test the lateral extension of the Swell Zone. MF23-211 successfully intersected thick spodumene-bearing pegmatite, with an average grade of 1.18% Li2O over 41m down-hole, with multiple sections grading over 2.1% Li2O. This key intercept helps validate the theory that the Swell Zone is expanding laterally.
Assessment and analysis of all four drill holes is being used to define the trend of this structure. Immediate drilling continues to test the Swell Zone. Testing at depth will be conducted once the more permitted drill pads are approved.
The significant mineralised intercepts in all four drill-holes reinforce the plunge theory and have extended the swell zone by 75m towards the west and 50m in depth.
The swell of mineralisation remains open at depth and laterally to the west as seen in long section. In some assays, thin mafic volcanic host rock inclusions that separate the pegmatite were included in the assay results where the mafic units would naturally be mined as part of accessing the larger pegmatite.
Future Work
Drilling is continuing to test and further define the Swell Zone. The western portion of the trend is a high-priority target area and has yet to be thoroughly drill tested. Drill core samples have been sent for assay with results pending.
“The follow up of the significant intercept in drill-hole MF23-207 has delivered immediate results, demonstrating that the Swell Zone extends up-dip, down-dip and laterally to the west,” Managing Director, Alex Cheeseman, said.
“Apart from proving the swell theory, which in itself signals a key breakthrough in the scale and growth potential of the Mavis Lake deposit, these intercepts point to an immediate and significant increase in tonnage which will form part of a future resource upgrade.
“We are on to something very exciting here and look forward to seeing the results from ongoing drilling, which is designed to extend the Swell Zone and underpin rapid resource growth that will give Mavis Lake further critical mass to underpin development of world class mining operation.”
