The protest started peacefully, but tensions started to rise over the lunch hour as SWN Resources Canada's vibroseis trucks approached the protest site.
At least 70 RCMP officers are at the scene, trying to encourage the estimated 50 protesters to obey the court injunction obtained by SWN last week.
Under the court order, protesters must stay 20 metres from the side of roads where the company is working and 250 metres away from the front or back of its trucks.
The highway was closed to all traffic for less than 30 minutes, but some vehicles are now being allowed through.
There was a violent clash between protesters and RCMP on Oct. 17 when police moved in to enforce another court order. Five police vehicles were burned about 40 people were arrested.
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