Locksley Resources (ASX:LKY) started diamond drilling at the El Campo rare earth element prospect at its Mojave Project in California, according to a Thursday filing with the Australian bourse.

The maiden program includes four initial diamond drill holes to test the depth and lateral continuity of mineralization along 900 meters of strike, where previous surface sampling returned results of up to 12.1% total tare earth oxide, per the filing.

The drilling is fully funded and is expected to take three weeks, with initial assays due later.

The company's shares were up nearly 3% in recent Thursday trading.