Boron (future) Uses, page-22

just the question left what happens at the end of 2021 if they dont brought the deposit in production?

As written in 12.2 a:

Following the initial term, the Elementis Mineral Lease Agreement may continue for so long thereafter as borate and/or lithium minerals are produced from the property or until terminated, extended or cancelled.

If not in production at the end of 2021, all possibilities are on the table. The outcome will depend on negotiations.