Elevra Lithium (ASX:ELV) said an updated scoping study for the expansion of its North American Lithium (NAL) mine has increased the incremental post-tax net present value (NPV) of the expansion project by 102% to $718 million from $355 million in the previous study, according to a Tuesday Australian bourse filing.

The company said the total NAL project post-tax NPV stands at $2.31 billion, with a post-tax internal rate of return (IRR) of roughly 42% and payback of 25 months.

The updated study increases the process plant design feed rate to a permitted average of 4,500 tonnes per day in Stage 1 and 6,500 tonnes per day in Stage 2, with expanded production of 338,000 tonnes per year of spodumene concentrate at 5.4% lithium oxide and an average life-of-mine recovery of over 71%, the filing added.

Total capital expenditure is $270 million across three stages, with Stage 1 incremental production ramp-up commencing in mid-2027 and Stage 3 construction forecast to be completed by mid-2029, with a revised mine life of 21 years, the filing added.

Average life-of-mine C1 unit cost is $628 per tonne and all-in sustaining cost (AISC) is $683 per tonne once the expansion is fully operational, it added.