St George Mining (ASX:SGQ) said drilling results continue to confirm potential for a substantial resource upgrade with thick, high-grade rare earths and niobium at its Araxa rare earths and niobium project in Brazil, according to a Monday filing with the Australian bourse.

Drilling yielded 100.6 meters at 4.82% total rare earth oxides and 0.64% niobium pentoxide from the surface, the filing said.

Shares of the company rose 15% on market close.