"Initially seven miners belonging to the Pakistan Mineral Development Corporation were kidnapped but two were later freed by the armed men," a police official said, adding no militant group has so far claimed responsibility for the kidnapping.
He said the five miners who were still with the kidnappers had been taken to a mountainous region near Quetta.
The kidnapping came a day after the blast in Sibi that killed five persons.
Baluchistan has been hit hard by a separatist insurgency that was revived in 2004. The separatists believe that locals do not receive a fair share of the province's energy and mineral wealth.