TESTAMENT TO A LEAD MINING HERITAGE
A lone, stone-built chimney stands sentinel on Malham Moor: a wild landscape that otherwise hides its industrial past. The chimney is a relic of an era when metal ores, such as lead and copper, were mined here during the 17th and 18th centuries. The ores were generally mined from the surface, where there were exposed seams, before being processed at a smelt mill. The chimney was connected to the mill by a long flue and acted as a cooling chamber from which lead could be removed; it also provided an effective draught for the smelt mill. It is believed that the mill on Malham Moor had fallen out of use by 1860, and there are no remains of the structure; the stone would have been plundered for building stone. However, the outline of the building and mill pond can be traced. On Malham Moor, the first recorded mining was at Dew Bottoms in the 1670s. Copper was mined first, followed by lead and then zinc. The spectacular landscape seen today would have looked very different, as the toxic fumes given off by the smelting process would have killed off much of the plant life, and it would not have been possible to graze cattle and sheep in areas near the mills; the introduction of long flues to dissipate the pollution helped to some degree. Some plants, however, did thrive, and the mining resulted in a very niche habitat, known as calaminarian grassland, a term that refers to the plant communities that grow in areas associated with heavy metal mining. Lead, in particular, is normally toxic to plants, but on the lead spoil heaps, plants known as metallophytes, which can tolerate or actually accumulate heavy metals from the soil, such as spring sandwort, Minuartia verna, with its delicate, white, star-like flowers; and alpine pennycress, Thlaspi caerulescens, can still be found where little else will grow. Some plants, such as wavy hair grass, Deschampsia flexuosa, have developed ecotypes, which are subtle adaptations that allow them to grow in particular conditions, but which are not significant enough to warrant being classed as a separate subspecies.