CRUX and SAMSO interviews, page-49

On brief review it appears the revised Mining Act - via the Statutes Amendment (Minerals Resources) Act 2019 (SA) was passed on 17 October 2019 and received assent on 24 October 2019:

https://www.legislation.sa.gov.au/LZ/V/A/2019/STATUTES%20AMENDMENT%20(MINERAL%20RESOURCES)%20ACT%202019_29/2019.29.UN.PDF (bit of light bedtime reading for you all)

If I can hazard an educated guess, the new and corresponding mining regulations will be in pIay by January 2021 on the basis that: “The Department is now finalizing mining regulations that sit beneath the revised Mining Act which will commence in January 2021”.

I have not yet located separate confirmation of the precise commencement date of the revised Mining Act, but the January 2021 is taken from the South Australian Department for Mining and Energy site you linked above.