Celsius Resources' (ASX:CLA) subsidiary Makilala Mining engaged DrillCorp Mining Resources and Construction for geotechnical and hydrogeological drilling at the Maalinao-Caigutan-Biyog project in the Philippines, according to a Wednesday filing with the Australian bourse.

The program will generate detailed subsurface models and data to optimize the underground mine plan, process plant layout, and surface infrastructure design, and inform the updating of the feasibility study and the front-end engineering and design phase, the filing said.

The drilling program is set to begin in mid-June, per the filing.

Shares were down 14% in midday trade on Wednesday.