Weardale > County Durham UK Lead Mining Mineral Specimens Fluorspar Rogerley Steetley Minerals

Weardale - County Durham, England
Minerals and Specimens After many centuries of mining, initially for lead and iron-ore and in later years, fluorspar, the last commercially worked mine, Frazer’s Hush, closed in 1999. The only present-day activities are specimen retrieval operations at Rogerley plus two large-scale quarrying operations which periodically hit mineralised ground. The best specimens are found in flat workings extending laterally from the host vein. The most prolific host strata for specimens is known as the Great Limestone with a thickness of up to 22 metres. Throughout the orefield three distinct horizons in the Great Limestone are prone to flat mineralisation often with large crystallised cavities. At Boltsburn mine flats extending for some 7,700 ft along the vein and up to 200 ft from it, have produced some of the finest fluorspar specimens in the world. More recently, in the late 1980’s, Frazer’s mine hit a huge cavity lined with beds of purple fluorite and smaller quantities of galena, calcite and sphalerite, whilst on the 325 level at Cambokeels a zinc-rich flat was discovered. After mining started in the flat, the drillers complained to the management that they couldn’t work the area because the drill rods kept disappearing into cavities! The ore-field is zoned laterally with the central area primarily fluorite and the outer fringes containing barite. Crystallised galena, calcite, siderite, quartz and pyrite also occur with amounts of sphalerite increasing towards the west of the ore-field. Specimens from classic Weardale locations are becoming increasingly difficult to find due to the end of commercial mining. Mineral Locations Beaumont Mine, Allenheads, Allendale, Northumberland Known for its specimens of lustrous wine coloured fluorite partially covered with sphalerite and siderite found in the early 70’s from Diana vein. These were a pale green colour when first brought out. Opaque purple fluorite cubes from Henry’s vein. Closed 1979. Blackdene Mine, St. Johns Chapel, Weardale Well known for its distinctive semi-transparent purple fluorite cubes tinged a honey brown colour. Specimens show cubes up to 6cms often associated with bright, modified galena crystals. Occasionally two to three cm amber fluorite twins occurred with green centres and exceptionally green and purple zoning, the latter from a single cavity found when driving the incline. Larger cubes occur up to 15 cms, but are usually opaque purple and white. It also produced elongated purple ‘floater’ crystals, some in the shape of a tower. Some fluorite specimens are dusted with small chalcopyrite crystals. From Silverdykes vein an offshoot of Slitt vein specimens of a pale yellow colour were found. Other minerals found were groups of modified bright galena crystals, the best found at the bottom end of the incline. Calcite occurred in many forms sometimes with curved crystal faces and usually coating the earlier fluorite. Large sphalerite balls to the size of footballs. The mine closed in 1987, all the recent workings off the incline now being flooded. Boltsburn Mine, Rookhope Possibly produced the most varied range of colours in fluorite (except green) with some of the largest and finest cubes ever found. Some were of such quality that they were used in optics. Many other aesthetic specimens with fluorite cubes partially coated with siderite, galena, sphalerite, pyrite and occasionally chalcopyrite. Unusual calcite crystal stalagmites. Although the flats were not exhausted, for economic reasons the mine closed in 1932. Cambokeels Mine, Westgate, Weardale (right) Also called Cammock Eels. The upper levels accessed via the horse level entrance have produced large crystals of pastel coloured fluorite, but it was only after the decline was driven in the 1970’s to reach un-mined sections of Slitt vein that Cambokeels showed its true potential as a specimen producer. These lower levels produced some of the finest pyrrhotite crystals in Britain. The 325 ‘zinc flat’ level yielded many excellent specimens of clear to turquoise fluorite crystal groups, with colour-zoning and high lustre, these dusted with pyrite or coated with small sparkling quartz crystals or calcite. Chamosite of a grey green colour frequently was a late stage coating to the specimens, the miners usually removing this with dilute hydrochloric acid. Although rich in zinc only small crystals of sphalerite were found in the flat and galena seems to be absent. On the 340, the lowest level, unusual pink transparent twinned fluorite cubes on quartz were found. Cambokeels was the deepest mine in Weardale, these lower workings being below the Whin Sill. All levels at Cambokeels produced fine specimens of calcite in many different habits, probably the best in Weardale. Zeolite specimens are also recorded. Cambokeels mine closed in 1989 and all the lower levels driven off the incline are now flooded. Cement Quarry, Westgate, Weardale Fluorite specimens are predominantly of a clear, wine or green colour with rare specimens of a rich transparent yellow. Purple phantoms are common in the green fluorite from here, which is a useful way to help distinguish specimens from those occurring at the nearby Heights Quarry, as is their darker colour in artificial light. Overall the specimen quality is poorer than Height’s material due to many specimens showing surface etching, possibly caused by acidic solutions in the surrounding mud. The quarry closed in 2003 and is now being heavily landscaped to remove the quarry faces. Dry Pry vein (NZ 014363) Anglesite is relatively rare in Weardale but at this location well crystallised specimens occur with crystals up to 5 or 6mm. The cavities occur in large lumps of galena up to 20cms with cerussite, the galena left over from when the mine closed, presumably there not being sufficient ore to warrant taking it to the smelter. Frazer’s Hush Mine, Rookhope Quite a prolific specimen producer, especially since the 1980’s when Weardale Minerals Ltd. acquired the operation. Many specimens came out of a single huge cavity hit during 1990 in the Great Limestone, stretching from the 340 level down to the 325 level, which produced beds of transparent twinned purple fluorite crystals up to 4 cm, some coated with calcite, sphalerite or galena crystals. Elongated ‘Floaters’ often with stepped crystal faces similar to those found at Blackdene were found, but sparingly. Green fluorite were rare but occasionally turned up from the workings on the 280 level, either on its own or partially coated with quartz. Besides fluorite, groups of bright galena crystals were recovered as were nail-head calcite crystal specimens and sphalerite on quartz from the 340 level. Greencleugh vein produced large, purple-white opaque fluorite cubes, individual cubes being up to 25cm across! Levels were numbered from sea level. The last level to be worked, the 260 level, produced small but outstanding purple fluorite groups. The mine closed in 1999 making it the last commercial worked mine in Weardale. Greenlaws Mine, Westgate, Weardale The mine has been re-opened for specimens in recent times although as of now (2008) it is no longer being worked. Some large purple cubes were found but they were not of the best quality. Old records suggest there are extensive flats in the mine containing amber and purple fluorite. Groverake Mine, Rookhope (right) Banded chalcedony often coating large cubes of fluorite with a second generation of smaller cubes. Quartz crystal beds were common. Worked for most of the 19th Century until 1985 then re-opened and worked in conjunction with Frazer’s Hush until closure in 1999. Heights Quarry and Mine, Eastgate, Weardale This quarry and mine have produced some of the finest quality specimens of lustrous green fluorite with inter-penetrant transparent cubes to 4cms. Also purple and colourless fluorite some with included 'bubbles'. Also various combinations of fluorite, galena, calcite and aragonite. Very large green opaque fluorite crystals up to 10cms were found in the West Cross vein. Early specimens from here were from Heights Mine which worked ironstone flats north of the quarry; as the quarry expands it occasionally breaks into the old mine workings. Newlandside Quarry Generally small fluorite cubes came out when the quarry was active. Newlandside is noted for the occasional larger twins up to about 3cms of an unusual transparent dark blue/violet colour. Redburn Mine, Rookhope Beds of small purple fluorite crystals usually on quartz. Also produced some excellent specimens of ‘Jack-straw’ cerussite. Closed in 1981. Rogerley Mine, Frosterley, Weardale (left) Rogerley is a small mine driven in the face of a disused quarry, initially developed by Lindsey Greenbank and Mick Sutcliffe, and since 1998 by UK Mining Ventures, for specimens. Quite a prolific producer of specimens with some excellent specimens of green twinned fluorite cubes even more fluorescent than Heights material. Sporadically it turns up large purple or amber fluorite cubes with quartz. Crystallised and Flos-ferri aragonite. Stotfield Burn Mine, Rookhope Lustrous, transparent grey-green and grey-purple fluorites. Modified galena cubes to 3 cms and occasional cerussite specimens similar to Redburn. The mine closed in 1966. West Pasture Mine, Stanhope, Weardale Beautiful apple-green fluorite cubes have been collected in recent years although the entrance has now fallen in. The colour is particularly unstable in sunlight and alters to a pale purple-brown. Also larger purple fluorite crystals. Whiteheaps Mine, Hunstanworth, Northumberland Light pastel coloured groups of fluorite with crystals up to 4cms. and occasionally of a deeper purple colour. Sphalerite and calcite specimens but rarely galena. Closed 1980.