IT'S hard to believe as you walk through the tranquil surroundings of Minera Lead Mines Country Park that this quiet corner of Clywedog Valley was once home to a bustling industry.

As its name suggests Minera has long been associated with mining with evidence of lead extraction dating back as far as the Roman occupation. The first clear documentary evidence of the industry appears during the reign of Edward I, when miners from Minera were sent to Cornwall to help develop the tin mining industry and extraction of lead and coal was later joined by the quarrying of silica stone and limestone, with three lime kilns being recorded in operation at Minera Mill in 1620.

Large-scale lime extraction began in the mid-19th century following the establishment of the Minera Lime Company. Several banks of large lime kilns were built during the nineteenth century, and investment from the mid-1860s resulted in the expansion of the works, including the construction of two huge Hoffmann kilns which were used for lime burning and brick making.

Following the closure of the quarry in 1993, the site has gradually been reclaimed by nature, but peer through the vegetation and you can still see the ruins of some of the massive structures which dominated the valley.

"What we're standing in front of our the late-Georgian and early-Victorian lime kilns," explains Ian Grant, senior archaeologist for Clwyd Powys Archaeological Trust (CPAT), as he shows me around the site. "There are very few of them still standing especially a bank of them like this and even more importantly the surviving Hoffmann kiln is one of only three remaining across the UK."

The recent transfer of ownership of the site from Tarmac to the North Wales Wildlife Trust has provided an opportunity to develop a Conservation Management Plan for the quarry. As part of this process CPAT are conducting a detailed survey of some of the limekilns and adjacent structures, in partnership with the North Wales Wildlife Trust and the Minera Quarry Trust, with funding from Cadw. Work has now started with vegetation clearance with the help of volunteers, and this will be followed by a detailed survey.

"The site here is really on a par with the steelworks in Brymbo," explains Ian. "It's not just the quarrying but all the infrastructure that was also in place and the other trades that were bolted on from here down to Wrexham.

"It was extremely dangerous too - quicklime is highly explosive and one thing it doesn't like is water and here we are right next to a stream."

The total output from the Minera area quarries was estimated, in 1859, to be around 300,000 tons, with 200,000 tons of this converted to lime. Extending from villages of Gwynfryn to Coedpoeth , and locally referred to as The Calch, the area’s lime quarries and kilns once had their own steam locomotive: Hornby and Dapol both have model wagons detailing the Minera Lime Co.

"In order to take any future plans forward we need a base plan map and a record showing the site in its present state so you can start to target what needs doing," says Ian. "A lot of the trees will ultimately have to go but we also have a lot of bats here so everything is being done carefully and by hand so we are only taking enough away so my guys can come in and digitally map all these structures and survey the site."

For a number of years plans have been mooted to open up the network of caves and tunnels to the public as part of a bid to transform the quarry into a significant tourist attraction. Numerous shafts and shallow workings are evident, some with horse-gins, as well as extensive open workings. Some of the veins lay close to the surface and were worked down from exposed outcrops, notably forming the deep, prominent scar known as Eisteddfod Hush. There are few surviving buildings, although the remains of the 19th-century engine house for Central Minera Mine still survive.

"One of the main projects we'd like to work towards is opening up the cave system to the public because there's nothing like it in North Wales," says Peter Appleton, of the Minera Quarry Trust, which was established in 2005 with the explicit aim of conserving the former quarry site for the benefit of the public. "I really hope it is developed. There is such a lot of interest whether it's in the site's geology, its natural history, its cave system or its lead mines. It could become something that is very important for Wrexham."