Lady Annabella Mine is UKMV’s latest surface exploration project. Start-up was in July 2020, working the only known remaining highly mineralised bench of the old Eastgate Quarry, also in Weardale.
First known to collectors as the Blue Circle Cement Quarry, beautiful Fluorite specimens have been produced ever since the quarry commenced operation in the early 1960s, and now our operations have indicated potential new mineralised areas.
Together with Rogerley, Diana Maria and Heights mines, Eastgate was well known for its emerald green Fluorite specimens, together with numerous colour variants such as yellow, yellow-violet, lilac, rose-pink, mauve and a wealth of colour zone combinations.
This new operation is proudly named for Annabella Bruce, Ian and Diana’s new daughter, born in June 2020. Specimen recovery is concentrated in a localised area of the former Eastgate quarry where anastomosing (branching and reconnecting) veins have created a complex patchwork of metasomatic flats, richly lined with crystallised Fluorite, occasionally associated with Calcite and Galena.
Throughout summer and autumn 2020, near-surface mining has exposed an amazingly diverse range of specimen-grade Fluorite in veins and pockets which change their entire characteristics across distances of less than a metre
The Lady Annabella mine is stratigraphically located in the upper part of the Great Limestone Formation of Carboniferous age.
The geology comprises of flat lying beds of cyclic limestone and shale units. Certain horizons within the limestone sequence exhibit fossils, namely corals, brachiopods, crinoids and stromatolites and these form a good marker zone for this particular bench within the former Eastgate quarry which Lady Annabella now works.
The quarry is traversed by a major splay shear, an off-shoot from the major WNW-ESE striking Slitt Vein. Splay shears form by the shearing of exiting faults or fractures, propagating at an angle to the former, and so significantly enhancing permeability pathways for migrating hydrothermal brines.
In this part of the quarry, three cross-cutting faults are intersected and displaced by the Shear Splay, named The Bull Vein, Fairy Hole Vein and Wilson Vein.
Summer-autumn mining operations have mainly focused on The Bull Vein. The central part of the vein is characterised by a prominent northeast trending strike-slip fault continuing into the immediate overlying limestone cap rock with en echelon, carbonate filled tension gashes displayed along its plane.
Blocks of limestone exhibit tilting and collapse towards the central fracture and mosaic breccias with abundant large cavities are well developed adjacent and to either side of the main fracture core, becoming smaller and “ribbon” shaped towards the periphery of the breccia.
Often, the distinction between vein and pockets is blurred along the sinuous Bull vein. It is characterised by sudden changes in the colour and zonation of the Fluorite, sometimes sufficient in number of specimens to warrant a specific pocket name and where this is not the case, specimens are recorded simply as The Bull Vein.
Yellow Fluorite is a good example, where distinct pockets have been named Sherry Twins, Harvest and Lemon Meringue, with all other variable yellows assigned The Bull Vein. The green zone in the accompanying diagram contains the Poison Ivy, Toxic Apple and Minty Cheesecake pockets.
The Fairy Hole Vein is located 28 m south and sub-parallel to The Bull Vein. The face of the excavation exposed a well-developed collapse breccia, capped by flat lying limestone beds.
The first specimens recovered from the Fairy Hole Vein have been named as from the Fairy Holes Pocket, and it is likely that future mining operations will reveal a continuation of this vein.
The Fluorite mined in 2020 is a distinct transparent green, although during the geological mapping in October 2020, the cross section of the Fairy Hole Vein structure exhibited on the working face of the pit contained many blue and purple specimens.
The Wilson Vein is located 20 m south of Fairy Hole Vein, with a similar strike orientation and forms the southern most exposed mineralised vein in the former Eastgate quarry, running along the edge of the remaining bench forming the Eastgate Hill.
The site was known by local mineral collectors and the fluorite specimens collected here were referred to as having come from Helen’s Pocket. The seemingly localised structure earned its designation as ‘Pocket’, but current mapping proved this structure to extend and outcrop 85 m to the south-eastern side of the hill where it is exposed as several vertical fractures running-up through the horizontally bedded limestone horizons. This pocket has produced interpenetrant Fluorite twins of a mellow yet rich leaf-green, a colour quite characteristic to this pocket.
This subsurface plan of Lady Annabella mine shows every major named mineralised pocket discovered.
|Date/Period||Pocket or Zone||Origin of Pocket Name|
|August 2020||Wilson Vein||For George and Matthew Wilson who collected the bulk of the original find in the late 1990s|
|August 2020||Helen's Pocket||For Helen Wilkinson, a well-known local collector and mine explorer who has done much excellent work to advance British topographical mineralogy|
|August 2020||Fairy Holes Pocket||For the nearby Fairy Holes Cave system containing the longest known stream passage in the Yoredale Limestone of the North Pennine Dales|
|August 2020||The Bull Vein||For Fred Bull, a well-known mineral collector who alerted UKMV to the presence of good yellow Fluorite in this, until then, unnamed vein|
|August 2020||Harvest Pocket||For the colours of the harvest and the autumnal landscape, with Fluorites from pale to deep yellow, some with beautiful pale skyblue outer zoning|
|August 2020||Sherry Twins Pocket||For the various Fluorite colours of sherry, a fortified wine, and its ubiquitous interpenetrant twinned Fluorite crystals|
|August 2020||Poison Ivy Pocket||For the Fluorite’s similarity to poison ivy, due to its mottled dark green colour with white veined cores and emerald-green gemmy edges and corners|
|August 2020||Toxic Apple Pocket||For its toxic appearance and the Latin Toxicodendron radicans, commonly known as poison ivy. A variant within the Poison Ivy pocket zone|
|August 2020||Layer Cake Pocket||For occasional layered small flat like structures running out from The Bull Vein with a pervasive deposition of Galena and Quartz crystals|
|August 2020||Lemon Meringue Pocket||For the resemblance of the bright zingy lemon Fluorite with milkywhite Quartz to the colours and textures of lemon meringue pie|
|September 2020||Minty Cheesecake Pocket||For the Fluorite’s remarkable similarity to cheesecake made from bubble-filled peppermint chocolate! A variant within the Poison Ivy pocket zone|
|October 2020||Sugar Plum Pocket||For the delicate plum-edged champagne Fluorite crystals, heavily coated in sugary micro-crystals of gemmy colourless Quartz|
|July 2021||Purple Rain Pocket||For the intense Purple colour of this Fluorite in combination with almost continuous rain while extracting the pocket. Annual rainfall averages 26 inches but working there it certainly feels like more!|
|July 2021||Hailstorm Pocket||For the white Hydrocerussite-coated Galena crystals, similar to golf ball-sized hailstones and even larger! Despite mining operations at Lady Annabella being confined to the summer months, the odd heavy hailstorm is not uncommon at this exposed site|
|September 2021||Jakub's Pocket||For Jakub Sauermann of the UKMV specimen recovery team, who discovered this football-sized pocket in The Bull Vein. It contained exquisite zoned yellow Fluorites edged pale sky blue|
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