Critica (ASX:CRI) started an air core resource upgrade drilling program at the Jupiter rare earth project in Western Australia, targeting the conversion of resources from the inferred category to the indicated category, according to a Wednesday Australian bourse filing.

The program comprises 143 air core holes for around 7,000 meters to 10,000 meters.

Regional drilling, supported under the Western Australian Government's Exploration Incentive Scheme Co-funded Drilling Program, started at the Juno target within the Brothers project and Aurora prospect, the filing said.

Critica's shares jumped nearly 4% in recent trading on Wednesday.