A new £40m (US$52.8m, €46.8m) planetarium at the site of a former coal mine in Wales will be one of the world’s largest when it is built, according to the plans.

Based at the Tower Colliery, which was the oldest continuously working deep coal mine in the UK until its closure in 2008, Planetarium Wales is an ambitious project that will feature a planetarium theatre, an experiential discovery centre and an education and research centre.

The initial planning and feasibility studies for it have been completed and Dark Sky Wales, the company behind Planetarium Wales, is now in the process of finalising those plans and taking consultations.

Sir Tim Smit, the man behind Cornwall’s Eden Project, has publicly backed the idea, which he hopes will be a driver behind economic regeneration in the Valleys and the Glamorgan area of South Wales.

"This is a great opportunity for Wales, in particular, the Valleys," said Smit.

"The Eden Project showed the positive impact such developments can have on the local economy. It has become a symbol of regeneration in areas, such as South Wales, that have similar demographics and face similar challenges.

"Whatever is spent on Planetarium Wales must be analysed, not just in terms of ‘what is the return of people coming to it?’ But, also, ‘what is it doing to lift the pull of low expectation and creating new economic thinking and social thinking within probably 30 miles of it?’ Now you will find that that will be a very significant figure.

"It just takes the one statement of faith in a place for other little statements to start and a culture to develop, and then before you know it, people are coming to learn, and an education infrastructure starts to develop."

Allan Trow, manager of Dark Sky Wales, said: "This is going to be a world-leading development. Unlike other planetariums in the UK, Planetarium Wales will seat up to 350 people and be among the largest planetariums in the world.

"Its distinctive size and use of futuristic technology will give visitors a unique opportunity where they can drift off into space and fully immerse themselves into space.

"It’s a multi-functional experience that will stimulate, educate and entertain all generations and support the local communities and areas in the long-run."