** Shares of Tivan ASX:TVN rise as much as 18.2% to A$0.130, their biggest intraday pct gain since January 16
** The critical minerals miner signs a joint venture deal with Tokyo-based Sumitomo Corp TSE:8053 for its Speewah Fluorite project in Western Australia
** Under deal, Sumitomo's unit to invest up to A$60.3 million for about 22.5% equity interest in the JV
** Adds that all parties have agreed on offtake of up to 100% of product over the project's lifespan
** Tivan stock up 20%, YTD