RE:Slr mineral resources and exploration update 2022More//////.......Sugar Zone
Maiden Sugar Zone JORC Ore Reserve at 30 June 2022 of 3.2mt at 5.1 g/t for 512,000 ounces, compared to non-JORC compliant estimate of 797,000 ounces at 31 December 2020, pre-mine depletion of 77,526 ounces to 30 June 2022).
The Sugar Zone Ore Reserve is reported at a >3.5 g/t cut off grade relative to the previous non-JORC estimate which was reported at a >5.0 g/t cut off. The Sugar Zone Ore Reserve comprises two mining areas, being the Sugar Zone and the Middle Zone. All mining to date has been at the Sugar Zone, with the Middle Zone scheduled to be accessed in H1 FY23.
The Sugar Zone lodes have a higher grade (6.5 g/t) and contribute 62% of the ounces in the Ore Reserve, relative to the thicker, lower grade Middle Zone (4.4 g/t) which has an average stope design width of 4.1m relative to 2.3m in the Sugar Zone.
The Ore Reserves reflect Silver Lake’s redesign of the Sugar Zone mine plan which consolidates the two Sugar Zone declines into a single decline at the 410 level. Breakthrough to the single ramp occurred in early October 2022 with the decline now progressing on a single heading at 5.0mW by 5.0mH dimensions. The Middle Zone will be accessed via a dedicated ramp off the Sugar Zone decline. Silver Lake has also increased level intervals from 15 metres to 17 metres and increased ore drive dimensions from 2.5mW by 3.0mH to 3.2mW by 3.8mH to facilitate the introduction of more productive, Automine equipped TOROTM LH307 LHD’s, which will be operated via teleremote from the surface, extending production bogging duration and efficiency.
The updated Ore Reserves assume the introduction of paste backfill commencing in Q1 FY24. The introduction of paste fill underground will provide a number of benefits including increased mine ore recovery, improved long term stope stability and result in a reduced life of mine TSF footprint with the majority of tailings to be deposited underground as paste.
Silver Lake’s redesigned mine plan will reduce development metres over the life of mine, increase operating efficiency and reduce costs.
The significant volume of material outside of the Ore Reserve and with Mineral Resources remaining open in multiple directions, there is a significant opportunity for future Resource to Reserve conversion, extensions of known lodes and potential for new high grade discoveries in the Sugar Zone deformation corridor to leverage the installed infrastructure. With Silver Lake now in operational control the initial exploration focus will be on grade control, Resource definition and immediate extensions with $7 million budgeted for drilling in FY23 with 2 underground and 1 surface drill rigs currently on site.
Figure 4: Sugar Zone long section showing FY23 min