Delving deep into the hidden treasure of our mines

A cycling holiday in Cornwall in my teens found me pedalling past the spoil heaps of the china clay industry: great pyramids of quartz sand gleaming in white peaks above St Austell. Later, on bleak skylines of cliff and moor, I was haunted by the gaunt silhouettes of ruined engine houses at the county's abandoned tin mines. The drama and disquiet of these images has lingered for half a century.

Ireland has industrial remains like this, too, but better hidden. The 60-odd hectares of Avoca's copper mines, with the awesome open pit of Cronebane, have never attracted the cameras of Ballykissangel, the TV serial filmed in the village nearby. Elsewhere, old mine engine houses, with their tall brick chimneys, are tucked into hillsides, shrouded in ivy.

But all this is changing, as Ireland's mining history is reclaimed as part of "heritage", good for tourism and local identity as well as for popular interest in geology and industrial archaeology.

This island's first small tourist mine, worked for silver and lead in the last century, opened two summers ago at Glengowla, near Oughterard in Connemara. In Wicklow, Avoca is planning a "themed mine heritage park" for an estimated 100,000 visitors a year. And Silvermines, in the hills of North Tipperary, is being developed as a National Mining Heritage Centre by the people who brought us Bunratty Folk Park and the banquets in Knappogue Castle.

No wonder that a document much in demand by local community groups is the Memoir of Localities of Minerals of Economic Importance and Metalliferous Mines in Ireland, written by Grenville Cole in 1922 for the Geological Survey of Ireland. It lists more than 140 mine sites, many of them small shafts, or adits, where only tens of tonnes of ore were extracted. In my own locality, I think of the perilously open shaft on High Island, out on the horizon, a difficult landing even in calm weather - it was mined for copper in about 1828 by the Martins of Ballinahinch. Just east of me, on a high slope of the Sheefrys, a series of adits was driven into the rock for silver at about the same time - wet, dark holes that need more of a crawl than I have the stomach for.

These are typical of Ireland's many "lost" mines, easily forgotten without engine houses or spoil heaps to mark them. The Mining Heritage Society hopes to add still more to the inventory, and to highlight the sites under threat from one cause or another.

The jewel in its crown is a building that stands proud as a Norman keep on the hill above Allihies in West Cork. The Mountain Mine Man Engine House (to use its full, resonant name) is unique in Ireland and one of fewer than 20 built anywhere in the world. Cornish by design, it used a steam engine to hoist miners up and down on steps fixed to a long timber rod. It is still relatively intact and ready-made for restoration.

A showpiece of this sort makes its own case for conservation. And a safe exploration of underground workings, plus a half-hour or so of exclamation and head-shaking in the museum up top has its obvious attractions as a heritage destination. Would you know what a horse-whim-and-winding-stow looked like? A treat ahead of you, in a replica at Glengowla.

But how far do we want to conserve the old workings of mining sites such as Avoca, Tynagh and Silvermines with their open-cast pits and quarries, waste heaps and tailing ponds? Visiting the South Wales valleys, Dr Matthew Parkes, secretary of the Mining Heritage Society of Ireland (MHSI), was quite put out to find the old collieries gone and the spoil heaps graded, landscaped and planted with grass and trees.

This, he felt, followed the social view that excavations and spoil heaps are inherently ugly. "I delight", he says with some fervour, "in the opportunity to see into the earth and enjoy the grandeur of such works." He is echoed by the MHSI's founder-chairperson, Dr John Morris, who derides "the ultimate, grotesque parody of conservation: engine houses in golf courses and fields."

This sort of restoration, they argue, is to deny the potential ecological diversity and richness of the new habitats created by mining and quarrying - from roosts for bats, unusual plant communities, bare warm ground for a whole tribe of insects, even new species evolving in mineral-rich ecosystems. Why try to restore the mining landscape to some imagined state of "naturalness", instead of waiting to see what nature makes of the changes that mining (rather than some earthquake or ice age) happens to have brought about?

Morris can go too far in his special pleading (mining toxic metals from the earth's surface, he says: "could be argued to be an act of environmental remediation"). But he agrees on the need to heal the worst visual scars, neutralise acid drainage and stop the wind-blow of toxic tailings dust.

Current Irish research is trying to work with nature and our distinctively moist climate to mask, filter and detoxify the formidable waste residues of mining. It has found lessons at Glendalough, Co Wicklow, where a natural marsh beside an abandoned lead-zinc mine has been effectively retaining metals for at least a century and is expected to do so for at least two centuries more.

The potential of wetlands, their microbes and plants, to lock up and transform metals in worthwhile natural habitats is the focus of the Wetland Ecology Research Group in UCD. At the Silvermines tailings dam, and at artificial wetlands at the Sligo Institute of Technology, thickets of head-high bulrushes wave above mud loaded with metal sulphides. They are emblematic of ecological answers to acid mine drainage and toxic dust.

Mining is a latecomer to our notions of "heritage", as it has been to the economy of the island. Given the challenge of coping with its wastes, perhaps we should be grateful for that.

Memoir of Localities of Minerals of Economic Importance and Metalliferous Mines in Ireland published by the Mining Heritage Society of Ireland (price £11 inc p&p) is available from Matthew Parkes, The Mining Heritage Society of Ireland, c/o Geological Survey of Ireland, Beggars Bush, Haddington Road, Dublin 4.