Diana Maria Mine

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The Diana Maria Mine

Frosterley, Weardale, County Durham, England

INTRODUCTION

In 2017 ownership of the Rogerley mining operation changed to that of Ian and Diana Bruce, under the name UK Mining Ventures Ltd. While initial upgrading of the Rogerley mine was in progress, opencast surface mining commenced around the outcrop of the old Sutcliffe Vein in Rogerley Quarry. This had only been very briefly worked by Lindsay Greenbank and Michael Sutcliffe back in the 1970’s and this new operation was named the Diana Maria mine (after Diana Bruce) and this, along with Rogerley mine, is now operated throughout the entire year.

Gemmy Lime Green Deep Purple Colour Zoning

Initial preparatory work at the outcrop exposed high quality, classic green Fluorite specimens which gave great encouragement to pursue the vein underground. Since the summer of 2017 the mine has been developed underground and is producing stunning world class specimens that include emerald-green, purple, some yellow Fluorites, multi-coloured zoned crystals, amazing twinned crystals and, rarely, crystals containing fluid inclusions in the form of movable bubbles. Occasionally the Fluorite mineralisation is associated with snowy-white Calcite which contrasts superbly with the colourful cubic fluorite crystals. Once again, the Fluorite emits amazing fluorescence in natural daylight.

Spectacular Fluorite specimens continue to be discovered as the Diana Marine mine and some of the most gemmy crystals are being used to produce beautiful faceted stones for both the collector and as jewellery.

Fluid Inclusion Faceted Rectangular Fluorite

HISTORY OF THE DIANA MARIA MINE

Origin and History of the Diana Maria Mine

Since the Greenbanks and Sutcliffes began exploring the long abandoned Rogerley quarry in the early 1970s, two mineralised veins have been known to crop out in the quarry face; the Greenbank vein and the Sutcliffe vein. These two veins strike normal (at 90°) to one another and all mining operations up to early 2017 concentrated on the Greenbank vein, exploited by Rogerley mine. Some collecting had been done from the exposure of the Sutcliffe vein by Lindsay Greenbank and Mick Sutcliffe using ropes and abseiling equipment, but this was difficult and so abandoned in favour of the Greenbank vein and the development of Rogerley mine.

The Diana Maria mine originates from the summer months of 2017, shortly after the Rogerley specimen recovery project changed ownership from its North American partners (UK Mining Ventures LLC) to Ian and Diana Bruce under the name UK Mining Ventures Ltd. (UKMV Ltd).

Before mining operations in Rogerley mine could resume, an extensive refurbishment programme had to be conducted to ensure full compliance with HM Inspectorate of Mines standards. While this work was underway the specimen recovery team turned their attention to the Sutcliffe vein, some 400m west of the Rogerley mine main portal, cropping out on the face of Rogerley quarry. Shortly after beginning removal of overburden adjacent to the Sutcliffe vein, richly mineralised collapsed flats were exhumed, hosting a stunning variety of Fluorite specimens and exhibiting wonderful daylight fluorescence. This was the first confirmed indication that exploitation of the Sutcliffe vein was a viable proposition and the operation to mine the vein was named the Diana Maria mine, for Ian's wife (Fig. 1)

Diana Maria Fluorite
Figure 1: Diana Maria Bruce, for whom the new mine is named, admiring a superb fluorite at the Diana Maria mine (opencast), Frosterley, Weardale (2017). Diana comes from a well-known family of mineral collectors in Saxony, Germany. Her paternal grandfather, Fritz Herrmann Schlegel, has the mineral Schlegelite Bi7O4(MoO4)2(AsO4)3 named in his honour.

WHAT'S NEW

Current mining activity (Friday 24th May):

Currently extracting Fluorite specimens from the Papa and Purple Haze pockets

Latest pocket discovery:

Papa pocket, so named for Diana's father.

New specimens:

A selection of the latest finds from the Green Sugar, Purple Haze and the newly discovered Papa pocket.

MINING OPERATIONS

Opencast Operations

Opencast mining operations commenced at Diana Maria in summer 2017. A track-mounted front hoe excavator was used to scrap back the overburden, soil and rock debris surrounding the outcrop of the Sutcliffe vein. Working down from the top of the quarry face, the excavation gradually opened-up an accessible working area around the vein, some eight to twelve metres below the top of the quarry face. Once down to this level, excavation of the site quickly revealed a complexity of large collapsed flat-style mineralised pockets following the Sutcliffe vein along its northern and southern flanks. A cross section of the Northern Flats at Diana Maria in shown in Figure 5, seen here in 2017. The section shows rich fluorite mineralisation lining a large mud, clay and rubble filled cavity. Other examples of such flats and specimens in the Diana Maria opencast section of the mine can be seen in Mining Operations and Specimen Recovery Photo Archive, Rogerley Mine.

Rich Fluorite Mineralisation
Figure 5: Rich Fluorite mineralisation exposed in the opencast workings at Diana Maria mine during 2017. This structure shows a collapsed metasomatic flat with the Fluorite mineralisation clearly visible around the slumped sides and across the base. Central to the structure is a mixture of collapsed rock and clay infill. This is one of the Northern Flats, so named as it lies on the northern side of the E-W trending Sutcliffe vein. The Northern Flats tend to contain purple Fluorite, but green is also present and appears deep purple when photographed due to its intense daylight fluorescence.

During the opencast mining phase at Diana Maria, the five pockets that were excavated were named Graeber Jones; Snowstorm; Pavel's; Emerald Peaks and Green Hill. To continue extracting specimens by opencast methods beyond this point was becoming uneconomic due to increasing volumes of overburden associated with steepening contours of Fatherley Hill. At this point the operation shifted to underground.

In spring 2019, exploratory work began on the River Catcher vein, some 35 m to the north of the Sutcliffe vein in Rogerley quarry. Clearing of the area around the vein outcrop began in April 2019 (Figure 6) and the early stages of collecting during May 2019 indicate the fluorite is predominantly yellow with some purple and green.

Stringers Stand
Figure 6: River Catcher vein stringers stand proud of the Rogerley quarry face at the left in this photo. The spoil in the foreground is mainly from the Diana Maria mine, but at this stage preparations are also in progress in making ready the area around River Catcher for sampling and initial specimen recovery.
Underground Operations
Mine Development

The Sutcliffe vein trends in a SW-NE direction, striking normal (at 90°) to the quarry face at Rogerley. From the adit portal, development of the main drive is designed to follow the Sutcliffe vein along strike. By following the vein, tunnelling control is maintained to target the more richly mineralised zones and reveal adjacent flats. This is different to a large-scale commercial metal mining where the main shaft and development is kept outwith the orebody and in the country rock.

In late April 2018, the quarry face adjacent to the Sutcliffe vein was scraped back of all unstable material using a hydraulic excavator and then hand cleared of any remaining smaller loose debris. Having excavated a shallow recess in the quarry face, a pre-engineered RSJ portal was positioned using a large hydraulic excavator jib. Photos of these operations can be seen in the Mining Operations and Specimen Recovery Photo Archive, Rogerley Mine area of this website.

The RSJ portal was then clad with timber and further protected by careful placement of graded rubble and boulders between it and the quarry face. To ensure slope stability, the boulders surrounding the mine entrance were carefully placed to maintain an angle lower than their angle of repose. This is the maximum angle at which a slope of loose rock is stable.

With all safety measures in place and inspections complete, drilling into the rock face could begin; this was the start of the Diana Maria underground phase.

Drive and cross-cut development are advanced using standard compressed-air rock drills with air-legs. Short rounds are drilled, charged and detonated to minimise shock to nearby mineralised pockets. Mucking out is by a track mounted EIMCO Model 12B rocker shovel. This machine, colloquially termed a 'mucker', is a rail-mounted pneumatic powered shovel that is used to quickly remove the blasted rock debris. The machine is controlled by a miner standing on a side-mounted narrow platform and is driven towards the rock face to fill the front shovel bucket. Once full, the unit is reversed and the bucket swings 180 degrees back over the unit to discharge its load into a waiting ore wagon, attached to a mine loco.

Roof and Rib Support

Although the overburden is minimal compared to deeper mines, its thickness does increase as the adit advances further under towards Howley Crag on Fatherley Hill. The overburden, consisting of well indurated limestones interbedded with thin shale, forms a weak overall rock mass due to shale partings, pervading open joint patterns and clay infilling. The limestone and ironstone have well defined bedding and vertical fracturing as a result of tensile failure during uplift contemporaneous with emplacement of the Weardale granite.

Once the mine working is excavated, the new void space acts as a sink to natural water flow within the hill and the increased flow rate weakens the more friable and water-reactive lithologies. Clay-filled joint planes gradually deform under stress once sections are developed or stoped-out and as a result, continuous roof support is required throughout the mine. In the early mining operations, arched rolled steel joists (RSJs) were installed with timber planking between them. In the current operation, square timber legs and beams are installed every 1.2 m, with timber boards in the roof where required.

Ventilation

Good airflow through the mine is essential not only to remove fumes following blasting, but because of the continuous entry of small levels of radon gas emanating from the Weardale granite some 400m below. Vertical fracture networks connect the granite to surface and hence the mine workings. Radon levels within the mine are constantly monitored to conform with HM Inspectorate of Mines standards.

Stoping and Specimen Recovery

Mineralised flats are extracted using a variety of both hand and power tools, but always by specialised mineral recovery miners, not development miners. Every size of hammer, rock chisel and prybar are employed, including nylon prybars strong enough to remove the tenacious viscous clay that surround specimen material, but non-damaging due to their plastic properties and low hardness.

As all mineral collectors know, great specimens frequently have no accessible face by which to begin extracting them. To overcome this, powered rock splitters and chain saws are used.

The rock splitter is a hand-held, hydraulically powered tool used for the delicate operation of specimen recovery, where conventional drilling and blasting techniques would destroy the fluorite specimens. The tool can be carefully manoeuvred by a skilled specimen miner to remove rock from around a pocket or mineralised vein, so the specimen can be extracted fully intact and without any damage. The narrow cylindrical probe is inserted into either a predrilled hole or natural fracture and under hydraulic pressure the probe expands causing the solid rock to gently fracture or for a crevice to expand. The probe can apply a force in excess of 400 tons (406,000 kg), but with minimal movement, no vibration and dust-free. All rocks are strong in compression but comparatively weak in tension.

A hydraulic powered diamond chain saw is used for the precision cutting and trimming of the rock. The diamond impregnated teeth quickly cut through all the rock types encountered in Rogerley. It is used both in the mine to cut specimens from the surrounding rock and at surface to trim specimens free of excess matrix. In the models we use underground, although hydraulically driven, the hydraulic power unit is pneumatically powered, so that air is vented to atmosphere and not fumes of any sort.

PHOTOGRAPHIC ARCHIVE

This section is a repository for photographs and associated information taken since mining operations began in 2017, documenting mineral discoveries and development of the Diana Maria mine.

Three photographic archives contain a wide selection of photos which will be added to whenever new material is appears.

PHOTO ARCHIVE 1: Mineral Treasures of Diana Maria Mine
Graeber Jones Pocket
Fluorite with cloudy green centres on quartz, 6.7 x 6.4 x 4.3 cm, exhibiting intense blue daylight fluorescence. Graeber Jones Pocket, Diana Maria mine, Frosterley, Weardale.
Colour-zoned Fluorite on Quartz, 6.0 x 4.7 x 3.3 cm, showing distinct colour zoning and purple-blue daylight fluorescence. Graeber Jones Pocket, Diana Maria mine, Frosterley, Weardale.
Close-up of the specimen featured in the photo above, showing beautiful and intense colour-zoning. The main crystal measures approximately 1.8 cm along its top right edge. Graeber Jones Pocket, Diana Maria mine, Frosterley.
Fluorite with Quartz. The uppermost cubic crystal measures 1.7 cm on edge; 14.5 x 12.2 x 6.5 cm. Another specimen with stunning mossy-green interiors and blackberry-purple corners. Graeber Jones Pocket, Diana Maria mine, Frosterley.
Fluorite on Quartz, 10.6 x 5.8 x 4.5 cm, with excellent colour zoning. Graeber Jones Pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite on Quartz with strong colour zoning and intense daylight fluorescence, 7.0 x 6.1 x 2.9 cm. Graeber Jones Pocket, Diana Maria mine, Frosterley.
Fluorite with blackberry-purple corners and mossy-green interiors, 10.1 x 11.0 x 4.5 cm. Graeber Jones Pocket, Diana Maria mine, Frosterley, Weardale.
Snowstorm Pocket
Purple Fluorite coated in drusy Calcite, 8.2 x 7.5 x 4.3 cm. Originally the Calcite was thought to be Aragonite, but this has since been analysed. Snowstorm Pocket, Diana Maria mine, Frosterley, Weardale.
Grassy-green Fluorite on drusy Calcite, 3.8 x 2.7 x 3.2 cm. Snowstorm Pocket, Diana Maria mine, Frosterley, Weardale.
Pitted green Fluorite twin coated in drusy Calcite, 2.2 x 2.3 x 1.8 cm. Snowstorm Pocket, Diana Maria mine, Frosterley, Weardale.
Purplish-green Fluorite directionally coated in Calcite. Artificial light (left) and mixed UV (right), 17.5 x 11.8 x 5.5 cm. Snowstorm Pocket, Diana Maria mine, Frosterley, Weardale.
Surface Opencast Workings
Calcite geode. Calcite forming meandering, stalactitic and tube structures with drusy coatings, lining an 8.0 x 7.0 x 4.5 cm vug in ironstone matrix; overall specimen size 11.4 x 8.5 x 7.8 cm. Initially this was thought to be Aragonite, but analysis gave Calcite. A one-off specimen found between the major fluorite pockets in the surface excavations at Diana Maria mine, Frosterley, Weardale.
Pavel's Pocket
Purple Fluorite with white Calcite, 11.9 x 8.2 x 5.5 cm. Pavel's Pocket, Diana Maria mine, Frosterley, Weardale.
Purple-green Fluorite displaying cloudy-white crystal centres, 7.2 x 7.3 x 4.3 cm. Pavel's Pocket, Diana Maria mine, Frosterley, Weardale.
Emerald Peaks Pocket
Fluorite on ironstone, shown in artificial light (top) and mixed ultraviolet (UV) (bottom), 9.9 x 5.0 x 3.5 cm. Emerald Peaks Pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite on ironstone, shown in artificial light (top) and mixed UV (bottom), 10.2 x 8.5 x 3.8 cm. Emerald Peaks Pocket, Diana Maria mine, Frosterley, Weardale.
Green Hill Pocket
Fluorite on massive yellowish-mauve fluorite, shown in artificial light, 16.4 x 13.0 x 7.8 cm. Green Hill Pocket, Diana Maria mine, Frosterley, Weardale.
Queen of Green Pocket
Gemmy lime-green Fluorite with overgrowths of snowy-white Calcite, 7.7 x 6.2 x 4.5 cm. Queen of Green pocket, Diana Maria mine, Frosterley, Weardale.
Lime to light spring grass-green Fluorite crystals with their edges tinged in fluorescent blue, 9.1 x 5.6 x 2.9 cm. Queen of Green pocket, Diana Maria mine, Frosterley, Weardale.
Lime to leaf-green cubic Fluorite crystals, some with modified faces and the larger central crystal containing a bubble fluid inclusion, 7.3 x 5.6 x 4.7 cm. Queen of Green pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite showing containing a spherical fluid inclusion (bubble) and tetrahexahedral upper face. Detail from specimen above; FOV 5.9 cm, overall specimen size 7.3 x 5.6 x 4.7 cm. Queen of Green pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite with Calcite. A splendid interpenetrant twinned Fluorite crystal framed with snowy-white Calcite. The Fluorite shows blueish-indigo daylight fluorescence and tetrahexahedral faces. 4.5 x 3.6 x 3.0 cm. Queen of Green pocket, Diana Maria mine, Frosterley, Weardale.
Single and interpenetrant twin crystals of Fluorite surrounded by a pervasive druse of snow-white Calcite, 10.0 x 8.3 x 4.0 cm. The Fluorite is shown giving an intense deep indigo fluorescence. Queen of Green pocket, Diana Maria mine, Frosterley, Weardale.
Detail of specimen above; overall specimen size 10.0 x 8.3 x 4.0 cm. Queen of Green pocket, Diana Maria mine, Frosterley, Weardale.
Rich mossy-green Fluorite crystals preferentially coated with snow-white Calcite, approximate size 12 x 9 x 6 cm. Queen of Green pocket, Diana Maria mine, Frosterley, Weardale.
Purple Haze pocket
Fluorite with Quartz. Deep purple Fluorite crystals partly overgrown with microcrystalline Quartz, 5.0 x 2.9 x 2.1 cm. The upper Fluorite crystal shows a distorted form of the cubic habit where each of its three axes are of a different length. Such crystals are uncommon from any of the Weardale mines. Micro-crystals of Quartz part-coat the Fluorite. Purple Haze pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite with sucrosic microcrystalline Quartz, 5.3 x 4.5 x 4.0 cm. Purple Haze pocket, Diana Maria mine, Frosterley, Weardale.
Deep purple Fluorite crystals partly overgrown with microcrystalline Calcite, 8.2 x 7.5 x 6.5 cm. Purple Haze pocket, Diana Maria mine, Frosterley, Weardale.
Detail of 8.2 x 7.5 x 6.5 cm, showing beautiful internal colour zoning, crystal growth features on the crystal faces and the splendid blackberry-purple colouration. Purple Haze pocket, Diana Maria mine, Frosterley, Weardale.
Detail of the main Fluorite crystal appearing an intense blackberry-purple in reflected light and exhibiting complex green, yellow and purple colour zoning in transmitted light, overall specimen size 5.3 x 4.5 x 4.0 cm. Purple Haze pocket, Diana Maria mine, Frosterley, Weardale.
Galena pocket
Galena with Fluorite and Quartz, 17.1 x 11.5 x 7.6 cm. Galena Pocket, Diana Maria mine, Frosterley, Weardale.
Galena with Fluorite and drusy Quartz, 13.0 x 10.8 x 6.5 cm. Galena Pocket, Diana Maria mine, Frosterley, Weardale.
November Gem pocket
Freshly extracted and washed Fluorite and Calcite specimen from the November Gem pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite with Calcite, 7.9 x 6.7 x 6.5 cm. November Gem pocket, Diana Maria mine, Frosterley, Weardale.
Gemmy Fluorite interpenetrant twin crystals with drusy snow-white Calcite, 9.3 x 7.7 x 3.3 cm. November Gem pocket, Diana Maria mine, Frosterley, Weardale.
Deep gemmy emerald-green Fluorite crystals with drusy Calcite, 10.3 x 7.2 x 4.3 cm. November Gem pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite with Calcite, 10.2 x 6.5 x 4.4 cm. November Gem pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite with Calcite, 12.4 x 10.0 x 4.2 cm. November Gem pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite with Calcite, 7.0 x 4.5 x 3.6 cm. November Gem pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite with Calcite, 22.0 x 10.9 x 4.8 cm. November Gem pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite with Calcite, overall specimen size 10.2 x 6.5 x 4.4 cm. November Gem pocket, Diana Maria mine, Frosterley, Weardale.
Frosterley pocket
Fluorite with Calcite, 8.8 x 5.5 x 3.4 cm. As is occasionally observed at Diana Maria mine, Calcite pervasively coats the smaller Fluorite crystals, but the larger crystals remain uncoated. Frosterley pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite with Calcite. Classic gemmy interpenetrant twin crystals of sea-green Fluorite with flashes of neon-green measuring to 1.2 cm, associated with white Calcite, 6.4 x 5.2 x 2.5 cm. Frosterley pocket, Diana Maria mine, Frosterley, Weardale.
Detail of Fluorite crystals measuring to 1.2 cm, associated with white Calcite on the specimen above; overall specimen size 6.4 x 5.2 x 2.5 cm. Frosterley pocket, Diana Maria mine, Frosterley, Weardale.
Emerald-green Fluorite fluorescing indigo-blue, 14.2 x 9.1 x 3.8 cm. Frosterley pocket, Diana Maria mine, Frosterley, Weardale.
Detail of Fluorite interpenetrant twin crystals; overall specimen size 14.2 x 9.1 x 3.8 cm. Frosterley pocket, Diana Maria mine, Frosterley, Weardale.
Detail of Fluorite interpenetrant twin crystals Fluorite with delicate blue daylight fluorescence; overall specimen size 14.2 x 9.1 x 3.8 cm. Frosterley pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite with minor Galena on iron stone matrix, 8.1 x 7.7 x 5.7 cm. Frosterley pocket, Diana Maria mine, Frosterley, Weardale.
Detail of Fluorite interpenetrant twin crystal with unusual matt, slightly frosted faces and subtle deep indigo daylight fluorescence. The cubic crystal is distorted with each edge a different length. Overall specimen size 8.1 x 7.7 x 5.7 cm. Frosterley pocket, Diana Maria mine, Frosterley, Weardale.
Gemmy green Fluorite with corroded cubic Galena crystals; overall specimen size 8.1 x 7.7 x 5.7 cm. Frosterley pocket, Diana Maria mine, Frosterley, Weardale.
Detail of Fluorite crystals with Calcite on the specimen above; overall specimen size 8.8 x 5.5 x 3.4 cm. Frosterley pocket, Diana Maria mine, Frosterley, Weardale.
Detail of Fluorite crystals, 8.1 x 7.7 x 5.7 cm. Frosterley pocket, Diana Maria mine, Frosterley, Weardale.
Green Sugar Pocket
Pale limey-leaf green Fluorite, mainly as single gemmy cubic crystals with white drusy Calcite overgrowing colourless clear Quartz, approximate size 7 x 4 x 4 cm. The areas of Quartz crystals appear a light chocolate-brown due to the underlying iron stone matrix showing through. Green Sugar pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite with colourless transparent Quartz crystals, 7 x 7 x 3 cm. The Fluorite crystals in this specimen have translucent mossy-green centres with gemmy corners and edges, the latter slightly fluorescing pale greenish-blue. Large areas of Quartz crystals appear a patchy chocolate-brown due to the underlying iron stone matrix. Green Sugar pocket, Diana Maria mine, Frosterley, Weardale.
Detail of daylight fluorescing Fluorite with minor drusy microcrystalline Quartz, 13.5 x 10.0 x 5.0 cm. Green Sugar pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite with Quartz and Calcite, approximate size 15 x9 x 5 cm. Green Sugar pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite with Quartz and minor Calcite, 16.8 x 14.0 x 11.0 cm. From this side the specimen has been likened to a duck. Green Sugar pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite with Quartz and minor Calcite, 16.8 x 14.0 x 11.0 cm. From this side it's more like the Loch Ness Monster! Green Sugar pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite on Quartz, approximate size 16 x 12 x 6 cm. Green Sugar pocket, Diana Maria mine, Frosterley, Weardale.
Fluorite with off-white drusy microcrystalline Quartz and creamy-white Calcite, 13.5 x 10.0 x 5.0 cm. Green Sugar pocket, Diana Maria mine, Frosterley, Weardale.
River Catcher vein
Golden toffee-yellow Fluorite with colourless Quartz crystals, 7.1 x 6.0 x 6.0 cm. River Catcher vein, Diana Maria mine, Frosterley, Weardale.
Golden honey-yellow Fluorite with fluorescing lilac corners and edges with minor colourless Quartz crystals, 8.6 x 5.6 x 4.0 cm. River Catcher vein, Diana Maria mine, Frosterley, Weardale.
PHOTO ARCHIVE 2: Mining Operations
Early fluorite finds at the Diana Maria opencast mine, Frosterley, Weardale in summer, 2017. L-R: Pavel Škácha, Peter Schlegel, Ian Bruce, Markus Walter and Mike Berry. During the summer months of 2017, Rogerley mine was undergoing refurbishment in compliance with HM Inspectorate of Mines standards. Meanwhile, the specimen recovery team turned their attention to the Sutcliffe vein, some 400 west of the Rogerley mine main portal. Shortly after beginning removal of the adjacent overburden, richly mineralised collapsed flats were exhumed, hosting a stunning variety of Fluorite specimens and exhibiting wonderful daylight fluorescence.
The second major cavity to be encountered amongst the collapsed flats at Diana Maria was the Snowstorm pocket. Here, boxes packed with 'Snowstorm' Fluorite and Calcite specimens are tightly packed into a van ensuring minimal movement while on their journey down to East Coker in Somerset for cleaning and trimming.
The approach to Diana Maria mine from Rogerley quarry in April 2018. When the Rogerley mining operation changed hands in early 2017 this roadway did not exist and the area around the Sutcliffe vein was a grassy slope, untouched since the original limestone quarry was active in the mid 19th century.
The Great Limestone unit exposed in the quarry face at Diana Maria mine. Deposition of the interbedded limestones and shales occurred on a marine shelf during the Namurian stage (326-313 Ma) of the Carboniferous period. The limestone is well indurated whereas the intervening shale units are relatively soft and friable, making roof support in the mine essential.
A large dissolution cavity in the Great Limestone unit which forms the quarry face at Diana Maria mine, Frosterley, Weardale (April 2018).
The Sutcliffe vein exposed in the quarry face prior to commencement of underground mining operations at the Diana Maria mine. The vein dips steeply at between 78° and 88° through the Great Limestone unit (28th April 2018).
On Sunday 29th April 2018, the quarry face adjacent to the Sutcliffe vein was scraped back of all unstable material using an hydraulic excavator. The face was then inspected and cleared of any remaining debris. The face was now ready for installation of the pre-engineered RSJ extended portal later in the same week.
Late April 2018. Having excavated a shallow recess in the quarry face, the pre-engineered RSJ portal was introduced in position. Once clad in timber and graded stone, this structure provides a safe working environment from which to begin tunnelling - the commencement of the Diana Maria mine.
The underground phase of the Diana Maria project commences! The RSJ portal is now timber clad and further protected by careful placement of graded rock between it and the quarry face. To ensure slope stability, the boulders surrounding the mine entrance have been placed below their angle of repose, that is the maximum angle at which the sloping surface of loose rock is stable. The rail track is now in place and the large diameter white tube is a ventilation duct to deliver clean air to the working development face.
Detail of the Diana Maria mine portal showing the timber clad RSJ frame and surrounding rock fill. The various service pipes entering the mine supply water, electricity, compressed air and ventilation.
Exposed dissolution cavities lined with Calcite crystals in iron stone replacement flats at the Diana Maria mine, Frosterley, Weardale (April 2018).
Interior of the Diana Maria mine portal as the development drive advances. Shortly into the mine the first set of track points can be seen. Ahead the rails follow the east-west trending Sutcliff vein; to the left (north) this branch leads to the Queen of Green pocket.
Roof of the November Gem pocket showing extensive Fluorite and Calcite mineralisation. Diana Maria mine, Frosterley, Weardale. As seen in the mineral specimens, the Calcite forms a pervasive coating over the Fluorite, but apart from the large Fluorite crystals. The Fluorite occurs here as deep and gemmy mossy-emerald-green sharp cubes, both as singles and interpenetrant twins. The creamy-white Calcite forms as undulating botryoidal coatings or delicate platy rosettes to 4 mm across.
Tramming blasted rock from the continuing development of the main drive at Diana Maria mine (2018). The rail track continues some distance outside the adit, across what was the opencast area of the mine when operations began in summer 2017. The ore wagons tip sideways on their bogies in order to quickly discharge their load.
A wagon in tipping mode outside the Diana Maria mine. Behind the wagon is the mine locomotive and this side, an EIMCO 12B rail-mounted, compressed-air rocker-shovel.
Fluorite specimen collected 21st May 2019 from the newly discovered Papa pocket in the Diana Maria mine, Frosterley, Weardale.
PHOTO ARCHIVE 3: People
Diana Maria Bruce, for whom the mine is named.
Vitek Ulbanski (Mine Manager, Rogerley and Diana Maria) with Ian Bruce (Mine Owner) in front of the Diana Maria mine portal (2018).
Keith Anderson, pictured here in Diana Maria mine, is UKMV's Resident Geological Engineer. Keith holds a doctorate in mining geology from Durham University and has always lived in County Durham. Keith's knowledge of the Weardale's mines, mineralisation and ore emplacement mechanisms is phenomenal and any discussion with him is fascinating.
Diana Bruce and Debbie Boyer (UKMV Finance Director) during an underground visit to the Diana Maria mine on 14th December 2018. Diana and Debbie are looking pleased with the roof support system and increased mass flow rate delivered by the new ventilation system.
Dan Holt (UKMV Sales & Marketing Manager) with Ian Bruce at the Rogerley mine main portal, Frosterley, April 2018.
Miroslav using a diamond chainsaw to remove excess matrix from a Diana Maria opencast Fluorite specimen; pictured outside Rogerley mine, Frosterley, April 2018.
A rather pleased looking Martin Stevko holding a very fine fluorite from the November Gem pocket (left) contrasts with a rather chilly looking Miroslav Volejnik. Martin is a consultant mineralogist and Miroslav is a specialist in specimen extraction.
Ian Bruce (mine owner, centre) with Jakub Sauermann (left) and Miroslav Volejnik collecting the first fluorite specimens from the Queen of Green pocket, Diana Maria mine. The large block of iron stone in front of the group is pervaded with green fluorite lined cavities surrounded with snowy-white calcite.
Jakub Sauermann holding a fabulous emerald-green fluorite specimen from the Queen of Green pocket by the entrance to the Diana Maria mine. Jakub worked at Diana Maria as an intern during his studies for a master's degree in Geology at the Adam Mickiewicz University (AMU) in Poznań, Poland. The old quarry face in the background shows an excellent section through the Great Limestone unit.

GEOLOGY AND MINERALISATION

Geology and Mineralisation at the Diana Maria Mine

In early summer 2017, UKMV Ltd. commissioned a consultancy to undertake geological mapping and modelling of the Rogerley quarry and adjacent area and it was during this investigation a third vein was discovered; the River Catcher vein. This is close to, and runs parallel with, the Sutcliffe vein. The three mineralised veins are plotted on the map shown in Figure 2 and a view of the Sutcliffe vein in relation to the River Catcher vein is provided in Figure 3.

Diana Maria Map
Figure 2: The three fluorite bearing veins cropping out within Rogerley quarry. The Rogerley mine works the Greenbank vein and the Diana Maria mine, the Sutcliffe vein. The River Catcher vein was only discovered in 2017 during geological mapping and modelling of the mine.
The North Face
Figure 3: View of the north face of Rogerley quarry clearly showing where the Sutcliffe and River Catcher veins outcrop. The vein stringers stand proud of the surrounding Great Limestone unit (Namurian) and are capped by shale (Stainmore formation). During mineralisation, veins have acted as fluid-flow conduits and the shale as a non-permeable barrier causing fluids to pond and extend laterally, so forming the flats.

The mineralised veins have formed within open faults within the upper unit of the Great Limestone. Figure 3 is an idealised sketch to illustrate some of the structural and mineralisation processes present in the Sutcliffe vein at Diana Maria mine.

The diagram shows a steeply dipping mineralised normal fault in a currently active state, thereby acting as a fluid conduit. In such a case, the term active does not imply movement is still occurring on the fault, but that the horizontal stress orientation is favourable to fluid flow. Other faults trending at around 90° to this would have remained "closed", acting as permeability barriers. Radial fractures emanating from the fault system penetrate the limestone parallel to bedding, so allowing the mineralising fluids to extend horizontally through the country rock. Other processes are noted in the diagram, such as permeability controls to fluid flow and colour distribution in fluorite.

Mineralisatiion
Figure 3: Sketch showing generalised mineralisation processes at the Diana Maria mine. The near-vertical Sutcliffe vein channels mineralising fluids towards the metasomatic replacement flats, constrained by overlying impermeable barriers such as shale. Philip Taylor figure.

These contain rubblised (brecciated) zones of high porosity and permeability and allow vertical fluid flow between horizontal beds of much lower permeability.

Since mining began at Diana Maria, the Sutcliffe vein is observed to be a more densely mineralised shear structure traversing old karst horizons. It has two distinct zones, divided by the vein/shear zone which runs East- West. To the right of the mine are the Southern Flats and to the left, the Northern Flats. The sheared and brecciated texture of the veins can be clearly seen in the River Catcher vein, Figure 4.

In the period to early summer 2019, the Northern Flats tended to produce purple fluorite, and this is where the Purple Haze pocket was found. The Northern Flats are more heavily mineralised than the Southern and tend to contain larger fluorite crystals, although often of an inferior quality to the Southern. Bucking this trend were the specimens from the Purple Haze pocket, many of which are magnificent. Examples of some of these can be seen in the Photographic Archive areas of this website. The Southern Flats tend to produce green fluorite, but in many shades and colour zoning habits. Examples include the beautiful gemmy crystals found in the Queen of Green and November Gem pockets. A marked mineralogical variation was that of the Green Sugar pocket, where Fluorite occurred with pervasive druses of 1 to 3 mm colourless Quartz crystals, often tinged green because of the Fluorite beneath.

River Catcher Vein
Figure 4: Close-up of the River Catcher vein showing a coarsely textured, rubblised, brecciated infill. These angular blocks of limestone and altered iron stone were produced by comminution within the fault while it was forming. Following the passage of mineralising fluids, a granular mineral phase can be clearly seen as a creamy-white cement.
Differences between Hydrothermal Vein and Replacement Flat-style Mineralogy

Changes in temperature, pressure, flow rate and flow direction, together with chemical reactivity with fault wall rock and rubble, have resulted in the precipitation and growth of fluorite crystals. These and other controls affecting Mineralisation in Veins, Replacement Flats and at Vein and Flat Intersections are set out in Table 2. The vuggy porosity provided within the brecciated fault zone provided the accommodation space in which crystals of fluorite and galena could fully develop; these are termed euhedral crystals and for which Diana Maria mine is now famous for. Other minerals present, but to a much lesser extent, are aragonite, calcite, hydrocerussite, quartz and smithsonite (Fisher and Greenbank, 2003; Symes and Young, 2008; Tindle, 2008 & Wilson, 2017).

Table 2: Some Controls in Vein, Replacement Flat and Vein/Flat Intersection Mineralisation
Chemical controls Physical controls
Fluid-chemistry properties Temperature
Fluid composition Pressure & pressure gradients
Fluid source: single or multiple Localised convection cells
Dissolved gas: type and volume Fault and orebody architecture
Acidity-alkalinity, pH Fracture geometry
Oxidation potential, Eh In situ stresses
Rock-chemistry properties Rock strength
Wallrock composition Rock permeability & porosity
Wallrock reactivity: fluid transport path Flow rate, flow path & duration
Wallrock reactivity: depositional zone Hydraulic connectivity

A common observation throughout the mines of Weardale is hydrothermal veins often contain larger, single, fluorite crystals (i.e. untwinned) and often of a more opaque, deep purple colour and to a lesser extent, green and yellow.

Around the sub-vertical vein system, metasomatic, horizontal mineralisation (flats) extends laterally; subparallel to the limestone country rock bedding. The limestone country rock shows extensive replacement by iron carbonate minerals (ankerite and siderite). Since deposition, these have oxidised through exposure to oxygen-rich groundwater and form a heavily iron-stained gossan-like matrix over which the fluorite has crystallised.

Mapping strike direction and geological modelling (Figure 5) of the veins indicate their intersection to the north of both current underground mining operations. Figure 5 also indicates the strike and dip of the Greenbank sub-parallel vein which bifurcates from the primary Greenbank vein very close to the Rogerley mine portal.

Research into controls on ore localization commonly indicate increased complexity in the mineralogy where veins intersect. The differences between hydrothermal vein and replacement flat-style mineralogy are controlled by many factors and can be summarised primarily into chemical and physical controls, as set out below. Such controls will also dictate any differences in vein and flat mineralogy around the where the veins will intersect.

This is due to any differences in chemistry and physical properties in the mineralising fluids (metal and fluorine-rich brines in the case of the Rogerley veins); orebody architecture and physical differences in localised temperature, pressure and fault genesis. Because the near-vertical veins acted as fluid conduits to the formation metasomatic flat-stale mineralisation, so near to the intersection of the veins the flats themselves may well contain new mineral species to the area and new Fluorite colours and zoning.

Modelled Veins
Figure 5: Modelled veins at Rogerley quarry and adjacent areas showing the Greenbank, Sutcliffe and River Catcher veins and their anticipated intersection. This model also shows the Greenbank sub-parallel vein. Progressive mining in both the Rogerley and Diana Maria mines will eventually arrive at the intersections, zones very often found to contain a more complex and exotic mineralogy. SRK Consulting (UK) Limited model and figure.
Colour Variants in Fluorite from Diana Maria mine

The cause of vivid colour in fluorite at Diana Maria and other Weardale localities is still not clearly understood. However, through modern analytical techniques and observation of colour change in specimens, it is believed green results from structural defects in the fluorite lattice (Fisher and Greenbank, 2003). In the 1980s and 90s, rare earth elements (REEs) were considered a major cause of colour in Weardale fluorite, but this is now largely discredited. However, fluorescence in Weardale fluorite is attributed to REEs.

Fluorite Green Fluorite Purple Fluorite Yellow Fluorite Multi-Coloured
Figure 6: Examples of colour and colour zoning in Fluorite from the Diana Maria mine, Weardale. Green (Queen of Green pocket); purple (Purple Haze pocket), yellow-lilac (River Catcher vein) and multi-colour zoned (unnamed pocket, Northern Flats). A discussion on the reasons why colour variation occurs in Weardale Fluorite can be found in the Weardale Mines area of this website.
Minerals

A relatively small number of mineral species have been found in the Diana Maria mine, typical of all mines along the Weardale valley. These are listed in Table 2 together with their chemical composition. It is apparent from Table 2 that there is also a limited number of elements present (C, Ca, Cd, F, Fe, H, O, Pb, S, Si and Zn) and these reflect the chemistry of the host rocks (mainly carbonates) and transported metals and halide (Cd, Fe, Pb, Mg, Zn and F).

The cadmium sulphide polymorphs Greenockite and Hawleyite are included in Table 2 following the discovery of small powdery patches on some specimens in 2019. Currently recorded as greenockite, analysis has yet to confirm if it is the CdS polymorph, hawleyite. Collectors will be familiar with these two species from many of the mines and quarries in Derbyshire and know how difficult it is to distinguish between them. As more information from specimens from the Diana Maria mine becomes available, this note will be updated.

Table 3: Minerals found at the Diana Maria Mine
Mineral Species Chemical Formula Word-formula
Calcite CaCO3 Calcium carbonate
Fluorite CaF2 Calcium fluoride
Galena PbS Lead sulphide
Greenockite / Hawleyite CdS Cadmium sulphide
Hydrocerussite Pb3(CO3)2(OH)2 Lead carbonate
Quartz SiO2 Silicon oxide
Sphalerite (Zn, Fe)S Zinc sulphide

CHECKLISTS

Since specimen recovery began in the summer of 2017, many collectors have built fine suites of Fluorite portraying the varying aesthetics of the different pockets and zones within the Diana Maria mine. Two checklist tables follow:

The first table summarises the Diana Maria mineralised pockets; their discovery date, pocket name and origin of the name.

The second table is an expansion of the former, containing more detailed information suitable to the advanced collector. Any notable specimens finds are also recorded in this checklist.

Summary checklist of named mineralised pockets – Diana Maria mine
Period/Date Pocket Origin of Pocket Name
Opencast operations
Summer 2017 Graeber Jones pocket For Charles Calvert "Cal" Graeber, Jr. and Ian Jones, British collector.
Summer 2017 Snowstorm pocket For the drusy coating of snow-white Aragonite over the Fluorite crystals.
Summer 2017 Pavel's pocket For Pavel Škácha, discoverer of the pocket.
Autumn 2017 Emerald Peaks pocket For the Fluorite's colour and crystal habit in this zone.
Autumn 2017 Green Hill pocket For the grassy green slopes of Fatherley Hill, on the side of which the Diana Maria mine is situated.
Underground operations
January 2018 Queen of Green pocket For the stunning colour, gemminess and perfection of the Fluorite crystals lining this magnificent pocket.
Autumn 2018 Purple Haze pocket For the smoky, very dark, almost black, purple Fluorite crystals, which appear a purple-coal black against the drusy snow-white Calcite coating.
Autumn 2018 Galena pocket For the proliferation of well-crystallised Galena amongst the Fluorite.
November 2018 November Gem pocket For the gem-quality Fluorite single and twin crystals and its month of discovery.
December 2018 Frosterley pocket For the nearby village of Frosterley, first recorded as Forsterlegh in 1239, meaning 'the forester's clearing'.
February 2019 Green Sugar pocket For the green-sucrosic appearance and texture of gemmy, colourless Quartz crystals overlaying green Fluorite.
May 2019 Papa pocket For Diana Maria Bruce's father and German mineral dealer, Peter Schlegel.
Checklist of named mineralised pockets – Diana Maria mine
The basis of this table is used with the kind permission of UK Mining Ventures, LLC. (Fisher and Greenbank, 2003; Fisher, 2011 & Fisher, 2013). All information from 2017 on is from UK Mining Ventures Limited (UKMV Ltd.)
Period/Date Zone/Vein/Pocket Mineralogy & Comments
Limestone quarrying period
Mid-19th century (actual operating period unknown) Working limestone quarry Opencast quarrying operation adjacent to, and north of the A689 Stanhope to Frosterley road. Limestone production. Minerals from the veins and flats were tipped in a waste dump.
Cumbria Mining and Mineral Company (CMMC)
1976 Surface work (un-named Sutcliffe vein) Lindsay and Patricia Greenbank with Mick and Brenda Sutcliffe discovered good quality green and purple fluorite in the, yet, unnamed Sutcliffe vein on the top bench of the disused quarry.
UK Mining Ventures, LLC (UKMV)
2000 Sutcliffe vein UK Mining Ventures, LLC was run by the partnership of Cal and Kerith Graeber and Jessie and Joan Fisher. This previously unrecognized mineral vein in the Rogerley Quarry was named the Sutcliffe Vein in recognition of Mick's contributions to mining and fluorite specimen recovery in this area. The vein was not exploited until the operation was bought by Ian and Diana Bruce in 2017.
UK Mining Ventures Limited (UKMV Ltd.)
Diana Maria Opencast operations
Summer 2017 Sutcliffe vein Development of the Sutcliffe Vein in the western face of Rogerley quarry. Between 10 to 20 ft. (3 to 6 m) of overburden removed resulting in the discovery of a 6 x 10m richly mineralised fluorite cavity. Produced emerald-green and blackberry-purple cubic fluorite crystals to 6 cm on edge and exhibiting an intense daylight fluorescent purple. The fluorites, often exhibiting rich colour zoning, are frequently found covering drusy beds of clear to milky-white quartz crystals. This working is approximately 125 m NNW of the Rogerley mine portal. Named the Diana Maria mine in honour of Diana Maria Bruce; joint Director of the mine and Ian Bruce's wife.
Summer 2017 Graeber Jones pocket The Graeber Jones Pocket was the first pocket discovered at the Diana Maria mine during June 2017. Initially it contained green, interpenetrant twinned fluorite crystals usually growing on equant, stubby quartz crystals, milky in appearance and tinged slightly yellow due to iron. The outer faces of the fluorite crystals tend to be a gemmy sea-green, with many of the centres slightly cloudy, in paler, mossy shades of green. This small zone quickly gave way to beautiful deep leaf-green to emerald-green twinned fluorites, often with distinct colour zoning. Zoned crystals often have a gemmy intense blackberry-purple centre surrounded with gemmy green faces. It is observed that these fluorites always grow on stubby quartz crystals, often of stalactitic form. Named for Charles Clavert "Cal" Graeber Jr., well-respected USA collector/dealer and one of the previous owners of Rogerley mine, and for British collector/dealer Ian Jones.
Summer 2017 Snowstorm pocket The evocatively named Snowstorm Pocket occurred at the contact between the Sutcliffe vein and mineralised flat. This contained gemmy green fluorite twins coated with snow-white aragonite. The fluorite occurs mainly as green gemmy twins on quartz overcoated with snow-white aragonite. Occasionally, crystals can be a grassy to sea-green and, rarely, a purplish-green. Named for the drusy coating of snow-white Aragonite over the Fluorite crystals.
Summer 2017 Pavel's pocket Pocket occurred on the south side of the Sutcliffe vein in a very hard jasperised limestone. The deep purplish-green fluorite is often prettily crazed with snowy-white centres and are typically directionally coated in drusy snow-white aragonite with one or two fluorite faces still visible. A frequent feature of this pocket is that of a larger gemmy purple twin emerging from the matrix. This observation of intense purple fluorite from the vein corroborates in-situ observations at the Greenbank vein. In daylight, the fluorite fluoresces an intense blackberry-purple. Named for Pavel Škácha, discoverer of the pocket.
Autumn 2017 Emerald Peaks pocket The Emerald Peaks Pocket is characterised by small green untwinned fluorite crystals coating an ironstone matrix, over which much larger, gemmy emerald-green twinned crystals grow. Specimens show remarkable artificial UV and daylight fluorescence. Named for the Fluorite's colour and crystal habit in this zone.
Autumn 2017 Green Hill pocket The Green Hill Pocket fluorites are most distinct with large intergrown single crystals, sometimes on a quartz matrix. The fluorites have beautiful gemmy corners with frosted and crazed green-mossy interiors, making spectacular combination. In daylight, the corners fluoresce intense blackberry-purple while their centres remain translucent, leaf-green mossy interiors, giving a stunning contrast. Named for the grassy green slopes of Fatherley Hill, on the side of which the Diana Maria mine is situated.
Diana Maria Underground operations
January 2018 Queen of Green pocket To be described.
Named for the stunning colour, gemminess and perfection of the Fluorite crystals lining this magnificent pocket.
Autumn 2018 Purple Haze pocket To be described.
Named for the smoky, very dark, almost black, purple Fluorite crystals, which appear a purple-coal black against the drusy snow-white Calcite coating.
Autumn 2018 Galena pocket To be described.
Named for the proliferation of well-crystallised Galena amongst the Fluorite.
November 2018 November Gem pocket Typical of the November Gem pocket are 1 cm + cubic crystals of gemmy, mossy emerald-green fluorite. The crystals which are not gemmy are often shades of moss-green with cream to pale creamy-green crazed centres. When crazed, the faces are typically crazed also, but with gemmy corners reminiscent of the Green Hill pocket (2017). Fluorite crystals are both single and twinned and the larger crystals exhibit magnificent deep mauve-blue daylight fluorescence. The gemmy cubes typically measure from 0.7 to 1.4 cm and are occasionally distorted. The Fluorite is often coated with creamy-white Calcite either as undulating botryoidal coatings or delicate platy rosettes to 4 mm across. The largest fluorite crystal is a 2.6 x 2.0 x 1.8 cm cube. Named for the gem-quality Fluorite single and twin crystals and its month of discovery.
December 2018 Frosterley pocket To be described.
Named for the nearby village of Frosterley, first recorded as Frosterley in 1239, meaning 'the forester's clearing'.
February 2019 Green Sugar pocket The Green Sugar fluorites range between candy-peppermint-green; emerald-sea-green, odd crystals showing internal yellow reflections to a beautiful deep leafy-emerald green. Cubes are typically about 6-8 cm and up to 1.5 cm on edge. The Fluorite is always associated with Quartz, and sometimes Galena and Calcite. The matrix is ironstone. Sucrosic 1-2 mm Quartz crystals richly coat many of the fluorite crystals. The quartz is colourless to light smoky brown and tan. Black galena crystals occur to 4 mm and form as modified cubes and octahedral crystals with flattened apexes. Snowy-white calcite may surround, and part cover the Fluorite crystals, some as small (5 mm) lenticular saucer-like crystals. Named for the green-sucrosic appearance and texture of gemmy, colourless Quartz crystals overlaying green Fluorite.
May 2019 Papa pocket To be described.
Named for Diana Maria Bruce's father and German mineral collector/dealer, Peter Schlegel.
ACKNOWLEDGEMENTS

The information provided on this website relating to mining in Weardale, Rogerley Mine and Diana Maria Mine is drawn from many sources. All referenced literature is listed at the end of each article, together with some additional useful references so providing a more general bibliography.

The current mining company, UK Mining Ventures Limited took over from the U.S.A. based UK Mining Ventures LLC, operated by Cal and Kerith Graeber and Jessie and Joan Fisher. Throughout this period Jessie Fisher methodically documented every aspect of mining activity, from mine development to specimen finds and some of his excellent articles are cited in the References. However, special thanks are made to Jessie for the vast amounts of detailed information he has supplied to UKMV Ltd., specifically to Phil Taylor who has been responsible for the website content. Jessie generously provided many specimen photos; pocket discovery information; detailed diary records and copies of the various published articles he has made over the years. As this website evolves, we hope to add more from Jessie’s archives as they provide an important addition to the history of mining in Weardale.

All employees of both UK Mining Ventures Ltd. and Crystal Classics Fine Minerals who have contributed their own photos and or information are thanked. Bryan Swoboda of Blue Cap Productions has filmed at several the UKMV mining operations and his excellent photos and videos are scattered throughout these webpages.

Jolyon Ralph of mindat.org is thanked for creating the original draft of this website, from which it has since evolved as new concepts and information have come forward.

REFERENCES

Benham, A., Naden, J. and Young, B. 2004. Re-evaluation of flat-style mineralisation in the Northern Pennines [poster] in Mineral Deposits Studies Group 27th Annual Winter Meeting, Leeds, UK, 6-7 January 2004. London, UK, Mineral Deposits Studies Group, 13-14.
Bevins, R.E., Young, B., Mason, J.S., Manning, D.A.C. and Symes, R.F. 2010. Mineralization of England and Wales. Geological Conservation Review Series No. 36. Joint Nature Conservation Committee.
Cooper, M.P. 1996. Classic Minerals of Northern England - The Lindsay Greenbank Collection. Private publication.
Dunham, K.C. 1990. Geology of the Northern Pennine Orefield: Tyne to Stainmore Vol. 1. HMSO (British Geological Survey Economic Memoirs), 2nd edition.
Edwards, R. and Atkinson, K. 1986. Ore Deposit Geology. Cambridge University Press.
Fisher, J.E. 2003. The Rogerley Mine, Weardale - A Condensed History. UK Mining Ventures. Web article: www.mineraltown.com/Reports/24/24.php
Fisher, J.E. and Greenbank, L. 2003. The Rogerley Mine, Weardale, County Durham, England in UK Journal of Mines & Minerals, Vol. 23, pp. 9-20.
Fisher, J. 2011. Rogerley Mine, UK – mining for fluorites in Minerals – The Collector's Newspaper; Issue No. 2. Spirifer Minerals.
Fisher, J.E. 2013. The Weardale Giant - A Large Fluorite Specimen Recovered from the Rogerley Mine, Weardale, Northern England, July 2012 in Rocks & Minerals, Vol. 88, January/February 2013; pp. 12-18.
Ixer, R.A. 2003. The Distribution or Rare Earth Elements in North Pennine Fluorspar and Fluorite in UK Journal of Mines & Minerals, Vol. 23, pp. 21-26.
Moore, T.P. 2016. Moore's Compendium of Mineral Discoveries 1960-2015. Volume I A-H. The Mineralogical Record, Inc., Tucson, Arizona, p.631.
Park, C.F. and MacDiarmid, R.A. 1970. Ore deposits. W.H. Freeman.
Pattrick, R.A.D. and Polya, D.A. (Eds.). 1993. Mineralization in the British Isles. Springer, Netherlands.
Praszkier, T. 2011. Rogerley 2011 – Penny's Pocket. Spirifer Minerals website: www.spiriferminerals.com/94,VII-2011---8211--Rogerley--Penny-s-Pocket-.html
Ralph, J. and Ralph, K. 2012. An exceptional British fluorite specimen - UPDATED. Mindat.org
Southwood, M. 2016. Who's Who in Mineral Names: Ian Robert Bruce in Rocks & Minerals, Vol. 91, January/February 2016.
Stone, P., Millward, D., Young, B., Merritt, J.W., Clarke, S.M., McCormac, M. and Lawrence, D.J.D. 2010. British regional geology: Northern England. Fifth edition. Keyworth, Nottingham: British Geological Survey.
Symes, R.F. and Young, B. 2008. Minerals of Northern England. National Museums Scotland and the Natural History Museum, London.
Tindle, Andrew G. 2008. Minerals of Britain and Ireland. Terra Publishing.
Wilson, W.E. (editor). 2010. The Lindsay Greenbank Collection - Classic Minerals of Northern England. Special supplement to the Mineralogical Record, Vol. 41 No. 1, January-February 2010.
Wilson, W.E. (editor). 2017. The Mineralogical Record Biographical Archive in the Biographical Archive on The Mineralogical Record website.

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