Provide a detailed explanation of the impairment write-down(s) made by Perseus Mining in the year ended 30 June 2021. This can be found on their 2021 Annual report. Your explanation should include a discussion of: i. the asset/s that were impaired; ii. the type of estimations required to record the impairment; iii. the amount of the impairment write-down; and iv. relevant disclosures in the 30 June 2021 financial report in relation to impairment testing.

What does the ii mean?