Hi BlumpThe pattern with RIO is generally an announcement of...

Hi Blump
The pattern with RIO is generally an announcement of proceeding the following year in Dec or Jan and then further announcement in April at start of drilling season.

For example:

29 January 2020 news that RIO proceeds to next stage and expected to commit to in excess of $2 million.
24 April 2020 RIO announces a $9.2 million program for year.

21 Dec 2020 RIO announces $13.8 m program for 2021
12 April 2021 2021 program is expanded to $24.5m

It's likely that it's April 2022 when we will know a more detailed plan and expenditure for 2022.

Probably relates to timing of decision making processes and budgets at RIO and analysis of previous years results.
The initial announcement probably relates to joint venture agreement requirements that they are proceeding to next stage, continuing expenditure type requirements and deadlines.