Environmental charities the Land Trust and Groundwork Merseyside have started work on the transformation of the derelict Cronton Colliery into a 100-acre park.
The first phase of work, on land deemed surplus by the Homes & Communities Agency, involves improving the old mineral railway line in Whiston, which will eventually form a safe route over the M62 and a link to Stadt Moers Park.
The HCA provided the Land Trust with an endowment of £2m towards future management costs.
Euan Hall, chief executive of the Land Trust, which now owns the site, said: "There is a lot of public support for the establishment of an informal country park at the colliery which has been agonisingly close to opening for a few years now. We recognise that people have had to live with a derelict site for a long time and have had to for wait for a number of years for any plans to become reality, so we've wasted no time in getting started once the site became ours."
However, Hall added: "We have to carry out the work in phases over a longer period than was initially planned because we have less funding than was originally designated. We are keen to open up as much of the park as we can as soon as we can and we will be talking with the community in the coming months to look at how best to schedule the work with the resources we have."
Cllr Dave Lonergan, cabinet member for regeneration at Knowsley Council, said: "I really welcome the fact that work is now underway to provide public access to the land at Cronton Colliery, which is something local people have wanted for some time now."
- Groundwork Merseyside welcomes volunteers to help with its work. Call 01925 207020