Cpl. Chantal Farrah of the RCMP says the protesters were disrupting work and traffic on Highway 126.
She says the seven men and five women are facing mischief charges.
There have been several protests over shale gas recently, with six others being arrested on the same charges over the last two weeks.
Opponents of shale gas exploration are against the practice of fracking, which uses large volumes of water and chemicals to fracture layers of rock to release trapped gas.
They say fracking will compromise groundwater, but the industry disputes that assertion.Suggest a correction