Spoil Heaps
Settlingstones 1967 © BGSThe district includes a varied legacy of mineral wastes in the form of spoil heaps from quarries, mines or mineral processing plants, including former metal smelting operations. Such spoil heaps typically comprise the geological materials discarded as waste from the deposit worked. Inevitably most spoil heaps also contain examples of the materials worked. As the area’s underground mines are no longer accessible for study, spoil heaps provide a unique source of material evidence for the materials worked, or penetrated, in the mine workings. Exposure to weathering in spoil heaps may enhance the value of the materials present. For example, many fossils which may be extremely difficult to see in an unweathered exposure or quarry face, may be clearly exposed in weathered blocks in a spoil heap. New mineral species may be forming within spoil heaps, particularly in waste materials from former smelting operations, as a result of near-surface (supergene) processes.
Spoil heaps are locally important elements in the area’s landscape. Indeed, many of the spoil heaps associated with metalliferous mines may be viewed as essential elements which help to characterise and define those landscapes. In some places spoil heaps may give the only clues to the presence of former workings. Spoil heaps may be rather vulnerable elements in the landscape.
Removal of rubble for earthworks or track-making, or reclamation of spoil heaps may damage them. Such reclamation activities may include tree planting or topsoiling of the heaps, both of which effectively render the materials contained within the spoil heap inaccessible for geological study. Natural erosion threatens a small number of scientifically significant spoil heaps. Collection of mineral specimens may seriously deplete the resource. Some spoil heaps provide an important habitat for a number of plant communities. These include limestone flora on the heaps adjoining some limestone quarries and metallophyte flora on numerous spoil heaps from metal mines and processing plants.
Several spoil heaps, particularly some associated with former metalliferous mines are included in the archaeological features scheduled at those sites. Scheduled Ancient Monument (SAM) designation normally precludes any form of disturbance, however minor. Spoil heaps may offer important potential for sustainable educational and recreational collecting.
Excavation of a spoil heap offers important opportunities for recovery of significant material and associated recording of finds. The spoil heaps associated with former coal mining are typically of modest size and are generally comparatively inconspicuous, but are in many cases the only present day expression of the former industry and provide valuable markers in tracing the position of coal seams.
A number of waste heaps associated with limestone and, to a lesser extent, sandstone quarrying contain weathered fossil material. Perhaps most significant are the large piles around Ridsdale and Bellingham containing the ‘shell band’ of the Redesdale Ironstone Shale, rejected as valueless by the ironstone miners.
In the south of the district, spoil heaps associated with the working of mineral veins at the Langley Barony, Stonecroft and Fallowfield mines remain. Most of the spoil heaps at the former Settlingstones Mine have been landscaped and although parts of the remaining coarse rock dumps are protected as an SSSI, for the mineralogical specimens they contain, they are becoming inconspicuous through increasing vegetation cover.
