The mine at Roy Hill was approved in 2009, however, under WA's Environmental Protection Act any changes to the approved plans must be assessed as well, which means Roy Hill must submit a revised proposal.
With iron ore quality differing across the deposit Roy Hill has been forced to open multiple pits at the same time to achieve the ore blend required by its customers.
That has led to extra dewatering requirements and a need for a managed aquifer reinjection program.
The extra work has also reduced the availability of backfill opportunities and left a lot of waste rock in the pits, which has forced Roy Hill to look at building surface water diversions so the waste rock doesn't flow over the pit walls.
Roy Hill wants to thus better manage water, materials and tailings.
Under the revised proposal Roy Hill wants to disturb 17,988ha instead of the approved 11,993ha in a development envelope of 97,946ha.
The company also wants a new in-pit disposal system and wants to amend its open waste rock management plans so it can backfill pits and build new waste rock landforms and a permanent surface water diversion structure.
The company also wants to revise the LoM water management strategy.
The proposal is open in a seven-day public comment period.