Mines in Rookhopeburn

The northwest-trending Red vein runs the length of Rookhopeburn (“burn” is a local term for a stream valley) and, along with its western extensions on the Groverake and Greencleugh veins, has been the site of several important fluorspar- producing mines during the last century. Detailed surveying by Dunham (1990) showed that major orebodies occur where the vein trend shifts to the west, and it was this work that led to the discovery and development of the Redburn mine in the 1960s. The Boltsburn mine was developed on the northeast-trending Boltsburn East vein from a point near its junction with the Red vein. Though now closed for the better part of a century, the flats discovered along this vein produced some of the finest fluorite specimens from the region. Though not as well known, the Boltsburn West Level, on the opposite side of the Red Vein was worked prior to the 20th century for iron ore from extensive flats. Although not technically in Rookhopeburn, the Stahnopeburn Mine is included here as it is located at the eastern end of the Red Vein system, which runs the length of the burn and hosts most of the Rookhope mines.

A map of the Red Vein system, which runs the length of Rookhopeburn, showing important ore and specimen-producing mines. Map by Bill Besse.

Boltsburn Mine

The main engine shaft of the Boltsburn mine is located on the west end of the village of Rookhope, south side of the burn and near the intersection of the Boltsburn and Red veins. The workings of the Boltsburn mine proper follow the Boltsburn vein to the northeast, though some work has been done on the southwest extension of the vein - primarily for iron ore derived from oxidized iron carbonates. The mine was originally developed for lead ore in the early nineteenth century by the Beaumont Company, and workings were developed along the vein in the Great Limestone and the overlying Coal Sills Sandstone. The vein, though rich in fluorite, produced only modest amounts of galena, and Beaumont gave up the leases in the early 1880s without discovering the incredibly mineralized flats for which the mine is now famous. The leases were subsequently taken over by the Weardale Lead Company, which initially continued working forward on the vein. In 1892 miners, following stringers of galena away from the vein, discovered the adjacent flats, which were separated from the vein by up to 20 feet (6 meters) of altered but largely barren country rock. It was also found that the miners had driven a considerable distance along the vein past the beginning of the flats before discovering their existence. The beginning of the flats is in the vicinity of the Redway rise, approximately 3,500 feet (1,050 meters) from the engine shaft and they continue the entire distance of the workings to the northeast.

A photo of the Boltsburn Mine taken sometime around 1900. Note the wooden structure enclosing the waterwheel to the right in the photo. Waterwheels were often enclosed at mines in the North Pennines to avoid power loss due to high winds and often freezing conditions. Photo courtesy of Beamish Museum Archives.

The main working level, known as the Watts Level, followed the Great Limestone from an initial depth of 179 feet (55 meters) below the collar of the engine shaft at Rookhope to a final distance of 2.1 miles (3.4 kilometers) to the northeast. Because the strata dips gently northward, the mine became ever deeper as work progressed, and eventually four additional underground shafts were sunk in order to have continued access to the Great Limestone. Despite the presence of ore at the face, the mine closed in 1932 because of labor problems and the high cost of transporting ore out of the mine. Pumping was maintained through the war but finally shut down in 1950. Most mine-related structures have since been removed and the main shaft capped, leaving little evidence other than some overgrown spoils heaps (dumps) of its former existence. Exploratory drilling in the 1970's showed that the flats continue at least 150 meters beyond the point where mining ceased (Dunham 1990). Despite this, it is unlikely the mine will ever reopen because of the high cost of rehabilitating the original workings or driving new tunnel to reach the flats.

A well-formed twinned, purple fluorite crystal, 5.5 cm on edge, with minor siderite, from the Boltsburn Mine.

The flats encountered in the Boltsburn Mine were, without a doubt, the best example of this type of mineralization found in any of the mines around Weardale. Besides yielding large amounts of galena, cavities in the flats contained numerous large, well developed fluorite crystals. Many of these were of optical quality, and exceeded 20 cm in size. Due to their perfection, many were purchased by German companies such as Zeiss for use in precision optical instruments. Fortunately, many were also preserved and now grace museum and private collections.

A transparent, twinned, pale lilac-pink fluorite crystal, 2.2 cm on edge, with numerous smaller fluorites, from the Boltsburn Mine.

The following description of these deposits is excerpted from "The Boltsburn Flats - Their Interest to the Student of Nature" by Stephen Watson, a mine agent for the Weardale Lead Company, which was published in 1904 in the Weardale Naturalists' Field Club Transactions. It is one of the few contemporary descriptions of such deposits ever published:

"The flats under notice in this paper are those in connection with Boltsburn vein, which are now being worked eastward from the watershed of Rookhope and Stanhope burns at a depth of over 100 fathoms below the surface, the mining excavations on which have revealed phenomena of interest to the geologist, the mineralogist, and the general student of nature....Instead of the usual well defined three flats we find one large flat, and as a consequence the loughs or cavities are on a larger scale than ordinary, in some cases forming caverns of considerable magnitude. These spaceous chambers give Nature the opportunity of modelling her creations on larger lines hence the massive cubes of fluor spar and huge bosses of crystallized galena. Entering one of these caverns immediately after being broken into by the miners, you find yourself surrounded by crystallized fluorite, the only stepping places being points and angles of six inch cubes. You admire the various shades of purple blue and heliotrope in the translucent crystals, and notice that some of the others are pale and cloudy. As you move carefully along its winding course, new forms of groups arrest the eye, and you note that some of the cubes are studded with calcite, and others are coated with fine white quartz, the diamond-like sparkle of the latter showing very effectively against the dark background of fluor. Another bend any you are confronted with an isolated cube measuring 12 inches across its face, and perfect in every line and angle. Having walked some 20 or 30 feet you find your further progress barred, although the vista of beauty still extends as far as the light of your candle can penetrate. Another type of lough is low and wide-spreading, paved with fluorite and roofed with pure galena 6 to 12 inches thick in some cases, chemical affinity thus showing itself curiously antigonistic to the force of gravitation; more commonly however these minerals are found irregularly distributed over floor and roof alike. Chalybite or iron carbonate sometimes predominates in a lough, every part of which is then rounded off and combed over with a moss-like formation, light brown, pale yellow, or whitish in colour, with a few minute crystals of fluorite scattered here and there upon its surface. Some of the smaller loughs are the most showy, the fluorite displaying a finer finish, the galena a more silvery lustre."

A cluster of well formed, penetration-twinned fluorite crystals, with siderite. 6 cm tall. From the Boltsburn Mine ca. 1920.

The Boltsburn mine is best known for its large, gemmy fluorite crystals, which are often penetration twins. The most common colors were shades of lavender to medium purple, but other colors, including pale olive-green, yellow, and amber were also found. Color banding in Boltsburn fluorite is usually not pronounced. Overgrowths of fine-grained, bronze colored siderite are often present on selected faces of the fluorite crystals. Stalactitic structures of fluorite-covered matrix were reportedly found on the floors of larger cavities (King 1982) and some excellent examples up to 30 centimeters long can be seen in the Russell collection at the British Museum of Natural History in London. Other associations include lustrous galena crystals of cuboctahedral to complex habit, “nail-head” habit calcite, and white druzy quartz. Other sulfides found in lesser amounts included sphalerite, pyrite, and rarely chalcopyrite.

A couple of well-formed, twinned fluorite crystals, with galena, on siderite. 10 cm across. From the Boltsburn Mine.

Boltsburn West Level

The portal to the Boltsburn West Level is located on the south side of Rookhopeburn, about 100 meters northwest of the original Boltsburn shaft, and has been driven southwest along the vein at the High Flats Horizon in the Great Limestone for over 8000 feet (2400 meters). Although mining in the area likely dates from at least the 17th century, modern workings on the Boltsburn West Vein were first undertaken between 1850 – 1875 by the Weardale Iron and Steel Company. Iron ore was recovered from extensive flats along the vein, in which massive deposits of siderite had been oxidized to limonite. After driving approximately 4500 feet (1350 meters) of tunnel the base of the oxidation zone was reached and mining ceased, as the unaltered siderite was not economical to extract as ore (Dunham 1939).

A photo of the 19th century workings on the extensive ironstone flats in the Boltsburn West Level. Photo courtesy of Mark Hardy.

Development of the mine was again taken up in 1930 by the Weardale Lead Company, in search of lead ore (galena). Unlike the Boltsburn East Vein, the flats and vein on the West were relatively poor in lead, and work was halted in 1941, after driving an additional 2100 feet (650 meters) of tunnel. At the beginning of the Second World War local geologist Kingsley Dunham conducted a survey of the mine to determine if there were sufficient iron ore reserves remaining to justify reopening the mine for the war effort (Dunham, 1940). Although reserves were identified, it does not appear that no further mining of any significance was done.

A specimen of fluorite with associated calcite and siderite recovered in 2017 from the "Blue Pocket" on the Boltsburn West Level. Largest crystal is 2.5 cm on edge.

Although properly identified specimens from 19th and 20th century mining on the Boltsburn West Level are quite scarce, a group of local mine explorers has recently re-established the entrance to the level, and gained access to the extensive older workings, much of which are in remarkable condition considering their age. A number of interesting specimen-containing cavities have been discovered, and a limited number of specimens have emerged. Particularly notable is a pocket zone known as the “Blue Pocket” that was discovered well into the mine below the oxidation boundary. Fluorite specimens from this pocket are quite lustrous, typically twinned and have an unusual deep blue color, unlike anything from other mines in the area. Associations include quartz, calcite, siderite, and galena.

Redburn Mine

The Redburn Mine was developed to recover fluorspar from a section of the Red Vein begining approximately one kilometer west of the village of Rookhope. The mine is one of the few in Weardale of completely modern origins. Data from surveys conducted by Sir Kingsley Dunham suggested the possibility of commercial-grade deposits along an unproven section of the Red Vein between Rookhope and the Groverake Mine. In 1964 the Weardale Lead Company drove an incline and reached a substantial vein of fluorite at the base of the Great Limestone. The mine was later taken over by SAMUK, and a mineralized section of the vein was worked for over 300 meters to the west. Levels on this section extended down to the Five Yard Limestone. A second mineralized section was discovered 1200 meters west of the first. This section was worked for an additional 610 meters from levels largely in the Great and Little Limestones. Extraction of fluorspar is reported to have been very thorough, and the mine was closed in 1981 when economic reserves were considered depleted. The site has since been completely cleared, leaving almost no evidence of the former mine site.

The Redburn Mine as it appeared in the early 1970s. After closure, the site was completely cleared and very little evidence of the mine remains today.

While not a major source of mineral specimens, the Redburn Mine did produce some interesting material. Pale to medium green specimens of fluorite, both twinned and untwinned, associated with quartz, calcite, and minor sulphides have been seen by the author. Groups of small purple fluorite crystals, as well as some good quality "Jack-Straw" cerussite specimens were also recovered from the mine.

A pale green penetration twinned fluorite crystal on quartz from the Redburn Mine. 5x5x4 cm overall size. Ex Arthur Scoble collection, mined in 1974.

Groverake Mine

The Groverake mine is located at the junction of the Groverake, Greencleugh, and Red veins about 4.5 kilometers northwest of Rookhope, near the head of the burn. Mining in the area likely predates the seventeenth century, but major development was started by the Beaumont Company in the late eighteenth century, including the sinking of two shafts on the Red and Groverake veins, which ultimately reached levels in and below the Great Limestone. While the veins proved very rich in fluorspar, they were relatively poor in lead and Dunham (1990) reported that between 1818 and 1883 they were able to produce only 6,498 tons of lead concentrates from the mine.

A photo of the Groverake Mine taken around the time of closure in 1999. The Frazer's Hush Mine may be seen just up the burn to the left of the main headframe. Both sites have been largely cleared and the only structure now remaining is the main Groverake headframe.

With the departure of Beaumont, the mine was picked up by the Weardale Lead Company in 1884 who, followed by a succession of several subsequent operators, worked the property for both fluorspar and lead until 1940. Problems with the treatment of the fluorspar ores to remove silica evidently limited the success of the mine during this period. More successful operations were begun during World War II by Blanchland Fluor Mines, Ltd., and followed by British Steel. During the British Steel tenancy, the Rake level was driven northward from the area of the shafts in order to access the upper levels of both the Red and Groverake veins, and the Firestone dib (dib is the local term for a decline) was put in to access lower levels on the same veins. Although these tunnels never interconnected with the shaft-accessed workings they are considered part of the Groverake mine complex (Younger 2003). Fluorspar deposits on both veins proved quite rich and the mine was to become one of the top fluorspar producers in the region during the latter part of the century. With the collapse of British Steel in the early 1980s the mine was acquired by Weardale Minerals and Mining, whose parent company Minworth, Ltd. was itself forced into receivership in 1991. The mine was then purchased by Sherburn Minerals and worked until the summer of 1999. At the time of its final closure Groverake was the last commercial fluorspar mine operating in the North Pennines.

A marker stone over the portal to the old W. B. Beaumont Company's horse level.

Despite its rich ore deposits, the Groverake is not known as a major specimen-producing mine. Dunham (1990) gave a detailed description of the mine and its orebodies but made no mention of any flats associated with the veins. It is possible that the lack of flats is the reason few specimens were encountered. Some fluorite specimens that did come out were a pastel green color unlike fluorite from any other Weardale mine.

A group of twinned, pale purple fluorite crystals, up to 3 cm in size, on a matrix of crystalline quartz from the Groverake Mine. Though the mine yielded relatively few specimens, the Groverake was the leading producer of fluorspar in Weardale during the 1980's and 1990's.

Frazer's Hush Mine

The Frazer's Hush mine was developed on the Greencleugh Vein, a western extension of the Red Vein a short distance northwest of the Groverake mine. Frazer’s Hush takes its name from a nearby hushing site that likely dates from medieval times. Although numerous older workings are present in the vicinity, the Frazer's Hush mine proper is recent. The current workings were first established in the early 1970s when a drilling program revealed substantial fluorspar deposits on the Greencleugh vein to below the level of the Great Limestone. Work was initiated by the Weardale Lead Company but was soon taken over by SAMUK, who drove two declines from surface. The Greencleugh dib accessed the higher portions of the vein, down to the 430 level, whereas the Frazer’s Hush dib eventually reached down to the 260 level. The levels of the Frazer's Hush mine are numbered in meters above sea level, unlike other local mines, which usually number levels by depth from surface at the mine entrance.

Operation of the mine was taken over by Weardale Minerals Company in the mid-1980s, and then passed along with the neighboring Groverake to Sherburn in 1991. The mine was operated until shutdown in 1999, and eventually joined up with the underground workings of the Groverake mine. As a result of its close association with the neighboring Groverake, the two mines are sometimes referred to as “Frazer’s Grove”.

Penetration twinned purple fluorite crystals, recovered from the 340 level of Frazer's Hush in 1988. 9x7x3 cm overall size.

During the early period of the mine few mineral specimens of any note emerged, but over a few years starting in 1988 a series of cavities were encountered that produced numerous specimens of glassy, transparent, twinned purple fluorite crystals, associated with quartz or sulfides such as galena or sphalerite. Most of these came from the 340 and 325 levels in the Great Limestone, and along with the prolific output from the Cambokeels mine at the same time they represent the last major period of specimen production from the Weardale mines.

Stotsfieldburn Mine

The Stotsfieldburn mine was developed on the Red vein in an area on the southeast edge of the village of Rookhope. The mine was originally worked between 1863 and 1878 for lead by the Rookhope Valley Mining Company. Two shafts and an adit were ultimately driven, but Dunham (1990) reported that recorded output of lead concentrates for this period was fairly low. The Weardale Lead Company reopened the mine in the early twentieth century for fluorspar, initially extracting it from dumps and backfill left during the lead mining period. Shafts and inclines eventually worked the vein from the Great Limestone down to the Three Yard Limestone, but by the early 1960s reserves of ore were becoming depleted, and the mine closed in 1966. There is no indication that flats were ever encountered in the Stotsfieldburn workings - or any other mine on the Red Vein. Because of this, specimens from the mine were never numerous, though some attractive specimens were produced. These included lustrous twinned crystals of purple and purple-green fluorite, often associated with shiny cuboctahedral galena crystals, and a white quartz matrix. Some excellent specimens from Stotsfieldburn are in the Robert King collection, now at the National Museum of Wales in Cardiff.

A cluster of lavender-purple penetration twinned fluorite crystals on a quartz matrix, from the Stotsfieldburn Mine. 15x9x4 cm overall size.

Stanhopeburn Mine

The Stanhopeburn Mine works the eastern-most part of the Red vein from a site along Crawleyside Bank, just north of Stanhope. The mine was worked sporadically for lead through the 18th and 19th centuries by a succession of companies, including the Earl of Carlisle, the London Lead Company, the Beaumont Company and Weardale Lead. Principal access was through the Shieldhurst and Widley levels. Dunham (1990) reports that lead values were generally poor and it is likely that the mine was abandoned by the early 1880s. The mine was reopened for fluorspar in 1906 by Weardale Lead, and again saw a succession of owners through much of the 20th century. The latest phase of activity at the mine was between 1971 – 1982 when the mine was owned by Swiss Aluminium UK (SAMUK). During this time the Stahhopeburn mine became one of the leading fluorspar producers in Weardale, but with SAMUK’s failure in 1982 the mine was closed again, and the plant dismantled soon afterward. Dunham makes no mention of flats associated with the Red vein in this region, which may account for a scarcity of specimens despite the mine’s output of ore.

A twinned fluorite crystal, 4.5 cm across, with minor chalcopyrite from the Stanhopeburn Mine, likely dating from the late 1970s.

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