A Thai court on Tuesday sentenced two military men to jail for orchestrating an attack on villagers blockading a gold mine, a lawyer said, a rare ruling in favour of such activists.

Residents of Nanonbong in the northeastern province of Loei have waged a decade-long struggle against the mine, operated by the Thai company Tungkum Ltd., which they say pollutes the environment and damages health.

The company has responded by filing at least 19 lawsuits against them, according to rights groups, including charges of criminal defamation against a 15-year-old girl.

In May 2014, a week before the coup that brought the current military regime to power, Nanonbong villagers said they were mobbed and beaten by over 100 armed men while they were blocking the road to the mine.

On Tuesday, a provincial court sentenced Poramet Pomnak and Poramin Pomnak, a retired army officer and his son, a serving officer, to two and three years in prison respectively for their involvement in the attack, the community's lawyer told AFP.

"In the verdict the judge mentioned that the two suspects hurt villagers to clear the way for transporting minerals," lawyer Sor Rattanamanee Polkla told AFP.

The pair, who were also ordered to pay compensation to some of the victims, were granted bail shortly after the trial and plan to appeal, she said.

The guilty verdict signals a rare departure from the impunity often granted to soldiers in a country where the military routinely intervenes in local and national politics.

Nadia Hardman, a legal adviser who observed the trial on behalf of the International Commission of Jurists, welcomed the ruling but urged a deeper investigation into others involved in the attack, which left at least a dozen injured.

"We are disappointed that only two people were indicted and found guilty," she told AFP.

She said over 100 community members gathered peacefully outside the courthouse Tuesday morning and handed out flower chains to police officers.

"It was quite an extraordinary gesture," she added.

Earlier this month, the Thai government announced it would shut down gold mining across the country following a decade of protests over environmental concerns.

It was an unexpected move as the current regime has pushed through a string of controversial environmental projects.

Thailand is considered one of the world's most dangerous places for environmental activists. More than 80 activists -- many of them fighting for land rights -- have disappeared or been murdered since the early 1980s.