REASONS FOR DESIGNATION
Nucleated lead mines are a prominent type of field monument produced by lead mining. They consist of a range of features grouped around the adits/and or shafts of a mine. The simplest examples contain merely a shaft or adit with associated spoil tip, but more complex and (in general) later examples may include remains of engine houses for pumping and/or winding from shafts, housing, lodging shops and offices, powder houses for storing gunpowder, power transmission features such as flat rod systems, transport systems such as railways and inclines, and water power and water supply features such as wheel pits, dams and leats. The majority of nucleated lead mines also included ore works where the ore, once extracted, was processed. The majority of nucleated lead mines are of 18th to 20th century date, earlier mining being normally by rake or hush (a gully or ravine partly excavated by use of a controlled torrent of water to reveal or exploit a vein of mineral ore). They often illustrate the great advances in industrial technology associated with the period known as the Industrial Revolution and, sometimes, also inform an understanding of the great changes in social conditions which accompanied it. Because of the greatly increased scale of working associated with nucleated mining such features can be a major component of upland landscapes. It is estimated that at least 10,000 sites, exist the majority being small mines of limited importance, although the important early remains at many larger mines have been greatly modified or destroyed by continued working or modern reworking. A sample of the better preserved sites, illustrating the regional, chronological and technological range of the class, is considered to merit protection.
True Blue Mine is a good and reasonably well documented example of a compact enclosed lead mining operation which retains a wide variety of mining and ore-working features. Its importance lies primarily in its completeness and good state of preservation and in its survival within an extensive mining landscape. Also important is its location in a mixed mining/farming landscape consisting of smallholdings and field barns and also characterised by the pond located in the mining area.
True Blue Mine is situated on the limestone plateau of Derbyshire on the shelves south of the Wye valley. The monument includes a walled enclosure containing the remains of a small 18th to early 20th century nucleated lead mine comprising both mineworkings and associated ore works. Further lead mining remains survive in the fields around the monument but have not been included in the scheduling due to their isolation from the core area. The monument includes a complex of earthworks which represent spoil heaps, dressing waste and shaft mounds containing shafts with rubble caps. On the north side of the enclosure, a sub-rectangular pit measuring c.3m x c.2m is interpreted as a settling tank used in the separation of lead ore from unwanted materials. On the east side, there is a circular pond. This pond was not used for washing lead ore but is contemporary with an earlier phase of mineworking characterised by a mixed mining and farming economy. Throughout the site can be seen the collapsed remains of small drystone structures known as coes. These include a pair of coes built against the western boundary of the enclosure and a range of three coes, each measuring c.3m square, extending east to west across the middle of the enclosure. Coes were used for a variety of mine-related purposes but it is likely that this range was used in ore processing as it occurs next to a level area which extends to the pond and is interpreted as a dressing floor. The remains of another coe survive against the north side of a circular enclosure located near the south west corner of the monument. This feature, which has a diameter of c.10m, represents a walled gin-circle and was originally the site of horse-powered winding gear. A depression in the ground marks the centre post of the gin while on the north side of the enclosure, there is a shaft capped with concrete sleepers. The well preserved stone lining round the top of this shaft is apparent through the sleepers. Between the gin-circle and the western edge of the mine there is a hollow way which leads to the range of coes noted above. Some of the mine workings indicate an 18th century date. However, some of the buildings are documented as dating to the late 19th century when the mine was worked by George Goodwin of Monyash. In 1913 the mine was taken over by E Garlick and was worked by the Magpie and True Blue United Mining Company until production ceased shortly afterwards. The mine does not exist in isolation but is part of an extensive and important lead mining zone which includes Magpie Mine to the west and Magshaw Mine to the east, mixed with a pattern of field barns and smallholdings deriving from a mixed mining/farming economy. One such field barn borders the mine on its east side but is not included in the scheduling. To the north of the monument there is a walled greenway called Trueblue Lane which served as a packhorse route. This lane connects with tracks leading westwards towards Sheldon and eastwards towards Magshaw Mine. A small enclosure opposite the junction of Trueblue Lane and Kirkdale Lane occurs next to latter and may have served as a corral for packhorses.
Book Reference - Author: Cranstone, D. - Title: The Lead Industry: Step 3 Recommendation - Date: 1994 - Type: DESC TEXT - Description: Site: Derbyshire 4