I make an annual pilgrimage to the limestone blast furnace slag slope (bit of a mouth full!) on the northern edge of the Gilchrist Thomas Industrial Estate, Blaenavon around this time of year for the plants and associated invertebrates. I've not done any specific research as to the origin of this slag but its a fair assumption that its a by-product of the nearby Blaenavon Ironworks now managed and showcased by CADW. However what limited knowledge I have about the industrial heritage of this area suggests that this mountain of slag has largely gone unnoticed by local armchair industrial historians.
This south facing slope is fringed in trees offering a micro-climate that benefits plant diversity, and as its a mainly limestone substrate it provides an island of variety within a wider sea of acidic habitats. The sparse yet colourful habitat is dominated by cats ear ( Hypochaeris sonchoides), ox eye daisy (Leucanthemum vulgare) and birds foot trefoil (Lotus corniculatus). Search more carefully and you will find blue fleabane (Erigeron acer), wall pepper (Sedum acre), southern marsh orchid (Dactylorhiza praetermissa) and common restharrow (Ononis repens). Day flying moths are represented by the limestone loving micro Pyrausta despicata and orthoptera by the mottled grasshopper (Myrmeleotettix maculatus).