The attack took place late on Saturday night, near the small town of Mach, not far from the provincial capital, Quetta, and close to the border with Afghanistan. Balochistan is the country’s largest and poorest region.
Armed militants kidnapped the miners from their shared residence and took them to some nearby mountains.
Six of the miners were already dead when found, and five who were critically wounded died on the way to a hospital, a local official is quoted as saying by Dawn newspaper.
A gruesome video from the scene shows the victims’ bodies strewn across the floor of a small hut – their hands had been bound together, reports the BBC’s Secunder Kermani.
Demanding justice, protesters laid the bodies out on a main road, blocking traffic.
Officials have promised to apprehend those responsible.
Members of the Hazara community has been frequently targeted by extremists from Pakistan’s Sunni Muslim majority.