Authorities said that damage to the site would be assessed once the fire is fully under control.
The regional Government’s tourism department plans a technical evaluation when conditions allow.
Unesco describes the site as “unquestionably the best preserved and most representative of all the mining areas of the Greco-Roman world in classical times”.
Spain has been in the grip of a heatwave for the past week, with temperatures nearing 40C in many areas and fuelling wildfires.
The northwestern Castile and Leon region alone has seen 13 fires in the past three days, according to Suarez-Quinones, who said that some were believed to have been deliberately started.
“Some can be explained by lightning or dry storms, but others only make sense if they are intentional,” he said.
In the southern tourist town of Tarifa, more than 2000 people were evacuated, some from hotels and beaches, after a fire that had been subdued on Saturday flared up again.
“We are continuing to work on its stabilisation. If you’re in the area: be careful and stay indoors,” Andalusian politician Antonio Sanz wrote on X, adding that more than 100 firefighters were tackling the blaze.
In neighbouring Portugal, firefighters were battling three large wildfires in the centre and north of the country.
The largest, near the town of Trancoso, has been burning since Sunday and was being battled by more than 650 firefighters backed by six aircraft.
- Agence France-Presse