The outline planning application – which will be determined by Caerphilly County Borough councillors on Wednesday, August 14 – includes 40% affordable housing, a cycle network and pathways to get around the site and spaces for sport and play.
The first two protests were held on Sunday, August 11, with horse riders and cyclists who use the land letting their feelings known.
Gwern y Domen Conservation Group chair, Cllr Jayne Garland, said: “The protests were amazing. On Sunday morning we had around 50 people come in the pouring rain and then we had hundreds come out in the afternoon.”
The third protest took place on Monday, August 12 and coincided with members of the council’s planning committee visiting the site.
Residents raised a variety of issues with the plans, including the impact on traffic in Caerphilly town, pollution, strain on public services and the loss of biodiversity.
More than 50 people attended the site visit, including South Wales East AM Delyth Jewell.
Ms Jewell said: “Once it’s gone, it’s gone. This land is used by the community and is of historical interest.
“This development wouldn’t be serving the people of Caerphilly.
“It would make Caerphilly a suburb of Cardiff and destroy the boundaries of the town.
“This area is very unique and has a particular character that can’t be replicated.
“There are natural wells here, this is not the kind of land that should be developed.”
Ms Jewell added: “A climate emergency has been declared. This is neglecting our past and our future.
“It’s all about money here and now.”
Cllr Elaine Forehead, who represents the St James ward where Gwern y Domen is located, thanked campaigners for their efforts.
Cllr Forehead said: “People have worked so hard on this. They’ve kept such a dignified presence and it’s been a pleasure to work with them.
“Ordinary people have been making such an extraordinary impact.
“This land is a gem. It would be a huge loss to the people of Caerphilly and to people across the county borough.”
Cllr Forehead added: “As councillors, we should be respecting the climate emergency motion.
“The planning committee don’t need to worry about what’s best for the people – because the people have spoken and they don’t want this development.”
Morgan Jones ward councillor, Shayne Cook, also attended the site meeting.
Cllr Cook said: “This development will have a detrimental effect on the residents of the whole of the Caerphilly Basin. The increase in the population will put a strain on local services such as schools, GP surgeries and dentists, which are already oversubscribed.
Cllr Cook added: “School admissions are already at breaking point. This development could have a big impact on school admissions in the future.”
Meanwhile, fellow Morgan Jones ward councillor, Jamie Pritchard, said: “I’m massively concerned with the recommendation to approve this application given the development will destroy the natural environment at Gwern y Domen.
“I believe the approval of this application would contradict the council’s recent important passing of the climate emergency motion. Preserving the environment should be foremost in the minds of councillors.”
Cllr Steve Skivens, who represents Penyrheol, is another critic of the plans. He said: “There are areas of Caerphilly County Borough that would welcome some development and to rid themselves of scars of the industrial age.
“But why is it that the lower end closest to Cardiff always seems under pressure? It is the developer’s wishes showing through again and again, for the most lucrative venues.”