She said it was lucky more people had not been injured particularly with the number of children in the crowd.
Police said the man left the scene but officers were speaking to him about the incident by 4pm.
Bob Brown Foundation campaign manager Jenny Weber asked any witnesses to speak to the police around the showground and provide any photos or videos of the incident.
Former Greens leader Bob Brown, who has been leading the convoy, said he had spoken to the woman, believed to be in her 60s, and she was conscious.
“There was a loud yahoo and this man rode between the crowd and the stage and coming out the gates knocked down a lady against the gates,” he said.
“He was yelling and waving his hat.”
Mr Brown said the woman had medical attention quickly and he hoped she wasn’t seriously injured.
The woman was a convoy participant from northern NSW, and her husband was with her as she was taken to hospital, Mr Brown said.
“It’s the sort of random thing that comes from inside of people,” Mr Brown said.
He said it was the kind of behaviour the right-wing politicians who vocally supported the pro-Adani rally on Saturday should condemn, and if it were him in those shoes he would.
Sunday’s separate rallies for mine supporters and anti-Adani protesters had been peaceful until the incident, following the convoy’s tension-filled arrival on Saturday afternoon.
On Saturday, pro-Adani residents, unions and organisations met the convoy at the gates of the showground, jeering, shouting, and waving signs.
One protester said a man holding a long metal bar swung it repeatedly at her windscreen and police received one call regarding possible shots fired at the showgrounds at about 10pm, but the caller said it was likely just a firecracker.
Residents had earlier gathered at a local pub in the town about three hours west of Mackay and 160 kilometres away from Adani’s planned Carmichael mine to send Mr Brown and his convoy a message: don’t tell us what to do.
Pro-Adani politicians including Clive Palmer and Pauline Hanson spoke at a rally before the hundreds-strong protest convoy arrived, confirming their support for the controversial mine to the joy of locals and unions alike.
Clermont resident of 48 years Carol Elly said if the mine didn’t go ahead, the town and others around it would collapse.
“It’s not just Clermont, it’s all the little mining towns around that get the benefit of it, the jobs and the money in the town,” she said on Saturday.
“Once the mining stops, the town will be dead.”
Convoy organisers had been keen to reframe Sunday as a peaceful ceremony titled Karmoo Dreaming, hosted by members of the Wangan and Jagalingou Family Council, the traditional owners of the region.
Wangan and Jagalingou man Adrian Burragubba has been locked in a series of bitter court battles attempting to block the Indian mining giant’s Galilee Basin project.
The day-long event at the showgrounds began with traditional dancing for the 200-plus crowd of environmentalists and activists.
Lucy is the urban affairs reporter for the Brisbane Times, with a special interest in Brisbane City Council.