GROUND investigations have shown the site of the Northern Quarter project is safe for development, says the scheme's backer the Homes and Communities Agency (HCA).

The state of the ground has been a particular flashpoint for controversy with opponents claiming that past extensive mining has made it dangerous to develop with the possibility of sink holes appearing.

Detailed survey work found nothing that could not be addressed with straightforward engineering and building techniques and a "negligible" risk of sink holes.

The HCA says sinkholes only appear where there are sufficient quantities of limestone or soluble bedrock near the surface disturbed by heavy rainfall – but the ground composition at the Northern Quarter is entirely different.

Up to 40 engineers have worked with 15 ecologists on the investigation of the site which is the proposed location for a new college, improved access road, hotel, business premises and homes.

Detailed tests took place at 150 locations around the site which has given the HCA and its partners "an extremely detailed understanding of the depth of former mine workings and the site's ability to accommodate new development."

The open cast mining that previously took place, which resulted in workings being filled in after use, has removed the risk of collapse at the former mining site.

The investigation work also looked for evidence of contamination and gas levels and did not find any issues that would need to be addressed before building work can start.

If the HCA's planning application for a new college, improved spine road, hotel and business premises is approved next month, the development would bring a new college for some 1,200 students, create 1,000 jobs and bring more than £100 million in investment.

David Warburton, HCA's head of area, said: "As a government body, we take our responsibilities in this area very seriously and have a strong track record of developing significant regeneration projects on sites like this across England, from Northumberland to Cornwall.

"The ground investigation works are a vital part of informing any construction that would take place on this site if planning permission is granted.

"We have done as much work as possible to establish a true picture of the conditions on the site. We have had a team of experts carrying out two phases of testing on the site and this has provided us with a huge amount of knowledge about the conditions.

"I am pleased that they have advised us that there is nothing on the site that couldn't be dealt with by straight-forward engineering and construction methods.

"People should not be surprised either that there are no sink holes on the site, given that they only appear in areas where limestone and soluble bedrocks are present. That is an important message that will give confidence to local people about partners' proposals to bring a superb education facility, jobs and investment to the Forest of Dean."

Councillor Tim Holder, Vice-Chairman of the Cinderford Regeneration Board, said: "The result of the ground investigation work is a real boost for this project, and proves that the site is suitable for development.

"These expert findings should reassure people that this is the correct site to deliver this once in a lifetime opportunity, for both Cinderford and the Forest of Dean."

The investigations covered the route of the proposed spine road, new junctions planned at the Northern United and Forest Vale sites and the site of the proposed college development close to Steam Mills lake. Detailed reports are expected within the next couple of months.