Allkem Limited provided an update for its Mt Cattlin operation in Western Australia. The company commenced a three-phase resource extension program in mid-April that targets 147 holes for approximately 32,685 metres of reverse circulation ("RC") drilling. The first two phases will target the immediate extension to mine-life at depth. The first phase aims to convert ~3.2Mt of resource from the inferred to indicated category. The second phase will test two pegmatite lenses of approximately 4.2Mt of existing inferred resource along strike and at depth in conjunction with a study to evaluate either the opencut or underground development of potential resource extensions. As of this date of this announcement, 60 holes and approximately 14,000m of drilling had been completed and an update on results will be provided later in September. The current drilling program is expected to be completed towards the end of CY22 and results have not been incorporated in the 2022 Mineral Resource estimate. The Mineral Resource Estimate at 30 June 2022 is presented in Table 1 and represents the combination of the 2018 Mineral Resource with a stand -alone 2021 2NW pit estimate, depleted for mining activities from 31 March 2021 to 30 June 2022. As in previous years the cut-off grade used was 0.4% Li2O whilst the pit shell used within which to estimate the Mineral Resource was generated at USD 1,100/t at 6% Li2O concentrate grade. The fiscal year 2022 Mineral Resource estimate takes into account both mining of resources from the current open pit mine and depletion of stockpiles, and includes results from the 2021 infill drilling results from the 2NW deposit. Remnant Mineral Resources under the backfilled 2SW pit has also been included as potential underground feed. A description of the major factors that resulted in changes from the 2021 Mineral Resource to the 2022 Mineral Resource are as: Resource model depletion of 1.4 Mt of material mined at a grade of 1.62% Li2O; Stockpiles depleted by approximately 510,000 t; Decline in Measured and Indicated grade due to the mining of higher-grade material in second half of current year 2021 compared to the life of mine grade; Reclassification of the RPEEE input revenue factor from USD 900 to 1,100 (at AUD/USD 0.70) for the generation of the pit shell within which the in-pit resource is estimated ­this development envelope is currently subject to development drilling; and An updated, depleted and integrated geological model in 2021. The Mineral Resource estimate, mining depletion and reporting was completed by Allkem staff. Allkem has assumed responsibility for the logging, sampling, analytical and quality assurance/quality control protocols currently in place for estimates and depletions. Ore Reserve: Allkem has reviewed and updated the Mt Cattlin Ore Reserve, incorporating 2021 infill drilling results from the 2NW deposit, the depletion of the 2NE pit and evaluation of remnant deeper resource under the 2SW pit. Within this review, depleted mined material and site stockpiles at 30 June 2022 and material to be mined after this date are presented in accordance with JORC (2012) Ore Reserve Reporting. Mt Cattlin's Ore Reserve at 30 June 2022 is presented in Table 3 and is based on the remaining Ore Reserves with the current mine design utilising the model from the 2021 Mineral Resource estimate
with the application of modifying factors. Like the 2021 annual review, modifying factors and mining reconciliation were reviewed by the
Competent Person and reflect Allkem's continued strategy to utilise front-end optical sorters to upgrade and process low-grade stockpiled ore. A dilution factor of 17% applied to the Ore Reserve and a mining recovery of 93% of diluted material reflects the current practice of mining to horizontal
flitches and benches. At 30 June, 2022 the 2NW pit pre-strip had advanced such that first ore had daylighted in the pit floor in blasted stocks, approximately 70Kt of ore has been depleted at the period end. A description of the major factors that resulted in changes from the 2021 Ore Reserve to the 2022 Ore Reserve is as: esource model depleted for ore extracted from the completed 2NE pit; An updated 2021 Mineral Resource Estimate and supporting Ore Reserve Study; Decrease in Ore Reserves due to open pit mining and stockpile processing; Decline in grade is due to the mining of higher-grade material in H2 CY21 compared to the life of mine grade; and Reconciliation indicates the now depleted 2NE pit delivered 1.4Mt @1.62% Li2O. The Ore Reserve does not take into account the infill drilling results from the 2NW deposit and the mine design has not been changed to take into account increase in Mineral Resources due to changes in pit shell. A revised mine design based on an updated Mineral Resource will be undertaken after the completion of the current major drilling programme. Appropriate assessments and studies have been carried out and include consideration of and modification by realistically assumed mining, metallurgical, economic, marketing, legal, environmental, social and governmental factors. These assessments demonstrate at the time of reporting that extraction could reasonably be justified.