** Shares of Terra Uranium rise as much as 10.7% to A$0.062, set to best session since Sept 27, if current gains hold
** The mineral explorer signs a definitive option agreement with ATHA Energy - a Canadian mineral co, giving T92 the option to acquire up to 70% of ATHA's Spire and Horizon projects
** Co says two projects consist of 12 mineral claims near Athabasca Basin, Saskatchewan, Canada
** Adds agreement to increase co's footprint in highly prospective Athabasca Basin
** Stock down 56%, YTD
(Reporting by Rajasik Mukherjee in Bengaluru)
((Rajasik.Mukherjee@thomsonreuters.com;))