The Mines Fire burning in Santa Clara County has grown with a dangerous rate of spread, Cal Fire said Monday.

The fire, which was first reported just after 2 p.m. on Sunday, has now burned 283 acres.

On Sunday night, CalFire said crews had halted the fire’s progression, and it had been holding at 40% containment through Monday. But by Monday afternoon, authorities said the aggressive blaze had spread. So far no structures are threatened.

The fire is centralized near Mines and San Antonio Valley roads in the San Antone Valley.

The cause of the fire is still under investigation.