Greenside Mine
Greenside Mine was a successful lead mine in the Lake District of England. Between 1825 and 1961 the mine produced of lead and of silver, from around 2 million tons of ore. During the 1940s it was the largest producer of lead ore in the UK. Unusually for a 19th-century metalliferous mine in Britain there are very full records of its activities, dating back to 1825.
The mine probably opened during the second half of the 1700s but had closed by 1819. In 1825 the Greenside Mining Company was formed and reopened the mine. They made good profits until 1880, after which price of lead fell. Many other lead mines closed at that time, but the company reduced its costs and continued to work Greenside until 1935. Electricity was introduced to the mine in the 1890s, and it became the first metalliferous mine in Britain to use electric winding engines and an electric locomotive. In 1936 the Basinghall Mining Syndicate Ltd. acquired the mine and turned it into a high volume lead producer. The mine closed in 1962 after lead reserves had been exhausted. Just before it closed the mine was used by the Atomic Weapons Research Establishment to conduct an experiment in detecting seismic signals from underground explosions. Fifteen years after the mine closed mine explorers began to visit the upper levels. They cleared the entrances and several roof falls, and today they are able to pass through the mine using an old escape route.
All the ore produced by the mine came from the Greenside Vein, a mineral vein which filled a geological fault running in a north–south direction through the east ridge of Green Side, a mountain in the Helvellyn range. Mining activities traced this fault for a length of and to a depth of. Four areas of the vein, known as ore shoots, contained galena, an ore of lead which also contained small amounts of silver. At first the ore was mined simply by driving adits into the mountain-side. To access ore at greater depths, two longer levels were driven from lower down but further away, and then a series of shafts were sunk within the mine. The lowest point in the mine was roughly 100 m below sea level, where the surrounding andesite rock rested upon underlying shales in which the fault had not been mineralised.
Two processing mills were built to crush the ore and separate out the galena from it, and the mine had its own smelt mill between 1828 and 1917, but after that it was more economical to sell concentrated galena to a commercial smelter. Machinery in the mine and the mills was powered by the plentiful water supplies in the area, used to drive water wheels and power hydraulic engines, and, after 1890, to generate hydroelectricity. Dozens of carts transported supplies to the mine's remote location, and carried the lead out. In the early 1900s the mine set up its own road haulage business using two steam wagons.
The men who worked at the mine during the 19th century travelled from a wide area, and many stayed each week in the lodging shops built at the mine. In time the company built dozens of houses in Glenridding and at Seldom Seen in Glencoynedale where a school was also built. Mining work was carried out by groups of men who took contracts to do specific jobs, and were paid by their results. Those who worked transporting ore out of the mine or processing the ore were paid at weekly rates. The closure of the mine resulted in a major loss of employment in the area.
The location
The mine was west of Glenridding village, which is by the southern end of Ullswater in the parish of Patterdale. This is now in Cumbria, but during the working life of the mine it was in the former county of Westmorland. Above the village is a valley which contains Glenridding Beck, flowing down from sources in Red Tarn and Brown Cove. A higher side valley to the north lies between the mountains of Green Side and Raise. It was above this side valley that the lead deposit was found, running through the eastern ridge of Green Side, at a height of about above sea level.In the 18th century this deposit was worked from levels driven directly into the mountain-side, above the upper valley. Later, levels were driven to the deposit from lower down but from further away. By the end of the 19th century, the main access to the mine was from the Lucy Tongue Level, which had been driven from near the bottom of the Swart Beck. The mills for processing and smelting the ore were in the same location, up the valley above Glenridding village.
Water power for working machinery in the mine and the mills was drawn from the stream below Green Side, and from Glenridding Beck. A number of dams were built to regulate the flow of water in these becks, and natural tarns at Red Tarn and in Keppel Cove were augmented. After 1890, water power from the becks was used to generate electricity and eventually three small power stations were built. A small stream was also diverted into the mine through the Glencoyne Level in the 1850s to drive hydraulic machinery.
The ore deposit
The entire production of the Greenside Mine came from a single mineral vein, which filled a north–south oriented fault running through the east ridge of the Green Side mountain.Green Side is composed of andesite rock, part of the Borrowdale Volcanic Group, formed during the Ordovician Period, roughly 450 million years ago. This rests on shales of the older Skiddaw Group, which were encountered in the lowest levels of the mine. A small dyke of porphyritic microgranite which has "a dog's-leg shape" in plan was intruded into these rocks during the Devonian Period; this formed a plane of weakness which controlled the position of the fault.
The Greenside fault is a normal fault with an average dip of 70° to the east. A fault plane is not a flat surface and the actual dip of the Greenside fault varies between 58° east and vertical; in one place it was 83° west. As the rock fractured and the two sides moved against each other, cavities were created, partly filled with broken rock. Hydrothermal circulation of sea water at temperatures of 110-130 °C, probably during the Carboniferous Period, led to mineralisation of the fault cavities. The metal content is believed to have been leached out of rocks of the Skiddaw Group, or the underlying granite batholith. The mineralisation of the fault shows some vertical zonation, with baryte in the upper part of the vein, and small amounts of both blende and chalcopyrite at deeper levels.
The argentiferous galena, which the miners sought, occurred as ribs, strings and dispersed pockets throughout the vein. Many strings of galena, varying in thickness between 1/8 of an inch and about, were interspersed through the vein, and sometimes spread into the rock on the east side of the vein. The mineralised parts of the vein were mostly found in four areas, known as "ore shoots." Their position was determined by the steepness of the fault plane. In general, areas where the fault dipped at more than 70°, were mineralised, but where the dip was less than 70° the vein was barren, filled with the light coloured soft fault breccia which the miners called "chunk." The mineralised parts of the vein, at least in the lower part of the mine, had an average lead content of 7%.
The width of the vein varied from a fraction of an inch up to or more. Barren sections were generally wide; worked areas varied from to as much as. In the upper part of the mine, where strings of lead had penetrated the hanging wall, it was sometimes worth cutting away an opening wide, but in the lower workings during the 1950s stopes averaged wide. Two branch veins occurred in connection with the microgranite dyke. At higher levels the vein divided and ran along both sides of the dyke. At greater depth, where the vein was within andesite to the west of the dyke, an East Branch was found in contact with the dyke.
At its southern end the vein came to an end as it approached the east-west Clay Vein by splitting into a number of small stringers, described as "a horsetail structure". All attempts to find the vein south of the Clay Vein were unsuccessful. The northern end of the vein was never determined, but all searches for lead beyond the limit of the northernmost ore shoot were also unsuccessful. The vertical extent of the vein was traced and worked from the top of Green Side down to the upper boundary of the Skiddaw Group, a distance of. Although lead veins have been found in rocks of the Skiddaw Group elsewhere in the Lake District, the strata at Green Side were unfavourable for mineralisation; these strata therefore marked the bottom of the mine.
Mining before 1820
It is not known when the Greenside Vein was first discovered, or when mining began there, but the amount of mining work done before 1820 suggests a date during the second half of the 1700s.There was mining activity in Patterdale throughout the 18th century. A lease for the mining rights at Hartsop Hall Mine is dated 1696; the parish registers recorded the burials of "a washer of ore" in 1713 and of a miner from Derbyshire in 1754; a census in Patterdale in 1787 recorded 16 miners out of a male population of 165 and a writer in 1789 spoke of social changes "about thirty years ago" resulting from an influx of miners when "some lead mines were wrought in the dale." Yet there is nothing to link any of these references to Greenside.
W. T. Shaw claimed Greenside was being worked by "a party of Dutch Adventurers" by 1690, but cited no evidence for this, and may have been thinking of other mines in the district. David Gough claimed "the first documentary evidence of mining at Greenside" was dated 1784, but also failed to say what that evidence was. Samuel Murphy discovered what he considered "the first documentary evidence" in the form of a barrister's brief of 1799, which referred to a Mr. Thompson who was working a mine at Greenside under the Duke of Norfolk. Murphy also found a reference to Greenside in William Green's guide book of 1819. The mines were said to be "beside the road from Keswick to Patterdale" and were "till lately worked by William Sheffield Esquire," the mineral agent to the Duke of Devonshire. The road mentioned is clearly the track over Sticks Pass, which passes the old workings at Greenside.
A vertical section through Greenside Mine was drawn by a consultant mining engineer in 1853. This shows three old access levels above the two levels which were in use at the time, and large areas of stoped out ground. W. T. Shaw calculated that the old levels, known as Top Level, Middle Level and Gilgower's Level, had been driven at, and below the summit of the ridge. Samuel Murphy calculated that the three levels had been 659 metres above ordnance datum, 631 metres AOD and 581 metres AOD. These three old levels imply a lot of mining work had been done before William Sheffield abandoned the mine, some time before 1819. In addition, a fourth old level was driven in this early period, and a fifth level had been started before the mine was abandoned.
The Greenside Vein may have been discovered among the rocks at the top of Glencoyne, where it outcrops and is visible. One branch of the vein was partly cut away at the outcrop, and a bell pit known as Duke's Sump was sunk on another branch "at some early date." Whether lead was found is not known. The vein may also have been discovered high up on the south side of Green Side. The hillside there is covered by a thick deposit of glacial boulder clay, hiding the rich lead-bearing vein from view. However, a natural gully intersected the vein high up and pieces of ore may have been found in the gully. Further down the hillside hushing has been used to reveal the position of the vein, by releasing a dammed up stream to wash away the boulder clay.
A survey of the surface features at Greenside Mine in the early 1990s found no sign of the Top Level. Of the Middle Level it found a shallow surface cutting at 627 metres AOD, a hole where the roof of the level had collapsed, a small waste heap, and a steep sled track running down the hillside from this point. The remains of a smithy were found lower down, near the base of the middle collapse hole, where there was a flat area at 584 metres AOD, with the foundations of a building and a scattering of coal, coke, slag and iron. Gilgower's level was identified with a waste heap and entrance cutting at 582 metres AOD. Below this was evidence of another level, driven at an elevation of 572 metres AOD. With a stone-walled entrance cutting and a substantial waste heap it appeared to be a major level, and had been driven from the bottom of the prospecting hush mentioned above. This level was not shown on the mine plan of 1853, and Murphy named it the Hush Level. A shallow water channel ran from its mouth and seemed to have drained the mine for a considerable time. The earliest Ordnance Survey map of the area, the 1861 map of Westmorland at a scale of 1:2,500, shows two mine levels, corresponding to Gilgower's Level and the Hush Level. Both are marked "Old Mine" showing they were no longer in use at that late date.
Once the ore had been brought out of the mine it had to be separated from rock and other vein minerals. The surface survey found evidence of an early dressing floor beside the marsh on the valley floor, at 550 metres AOD, where a little stream provided a small source of water. In that area were found many pieces of very weathered galena. It also found the washings had later been moved to another area beside the marsh, which could be supplied with a more reliable water supply. A leat had collected water from the original stream, 36 metres above the old dressing floor, and conducted it to some small storage ponds further east, which could collect from other sources as well. However the site of the new washing floor had been destroyed by a later mine building. After the ore had been dressed it was taken by packhorses over Sticks Pass to a smelter at Stoneycroft in the Newlands Valley, near Keswick.