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November, 1951

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Greenside Mine, the property of the Basinghall Mining Syndicate Limited, is one of the largest lead mines in England, and also, holds the distinction of being the oldest producing lead mine in the north of England. It is situated amid beautiful scenery in the English Lake District, about a mile from Lake Ullswater, on the eastern slopes of the Helvellyn mountain range, with an elevation of 1,000 feet above sea level. It is approximately midway between Penrith and Windermere, being about 15 miles from each town.

Ullswater, in common with other lakes in the district, is a tourist centre during the summer months, trout fishing being one of the principal attractions.

The early history of the mine is somewhat obscure, but it is not unlikely that it was discovered in Roman times. It is known, however, that modern operations date from the latter part of the eighteenth century.

About 130 years ago it was bought by the "Greenside Mining Company," who until 1935 mined to a vertical depth of 2,047 feet below surface on a strike of 2,000 feet yielding about one million tons of broken ore, or 100,000 tons of concentrates carrying 79 per cent, lead and 10 ounces of silver per ton.

Operations in the early days were begun at about 2,000 feet above sea level. The washing and dressing machinery were, according to old reports, primitive and were only workable nine months out of the year, frost and snow interfering with milling during the winter months. The ore at that time was conveyed for smelting to the neighbourhood of Keswick on the backs of horses.

In 1931 the Greenside Mining Company's reservoir at Kepple Cove burst during a gale, causing extensive damage to property in the Glenridding Valley. Compensation following this disaster was heavy, and the company suffered financially. Also the price of lead was extremely low at this time.

The Basinghall Mining Syndicate Limited took over the property in 1936, and between that time and January, 1951, have treated 516,493 tons of mine ore yielding 49,512 tons of concentrates averaging 79 per cent. lead as before but only 6 ounces of silver.

Geology

The part of the Lake District in which the Greenside Mine lies is built up of a series of lavas and tuffs, chiefly rhyolitic and andesitic, folded in a complex pattern, and intruded by quartz porphyry.

Most of the rock has a green coloration, possibly the origin of the name of the mine, and is locally called "Greenstone." It is often associated with rich mineralisation, and also gives rise to difficulties in milling. It is very fine grained, brittle, and contains numerous small sulphide-filled gash veins.

Mineralisation is linked with the "Greenside fissure" which strikes a few degrees off N-S, with a strike length of at least 7,200 feet, and varies up to 250 feet in width. It is cut off to the south by a strong E-W fault, the "Clay vein," of unknown throw. Other E-W fissures are common, and pyrite and copper minerals in any quantity are restricted to their vicinity. For the most part, these E-W fissures are thrown by the Greenside Vein, which is described below, but a few of them interrupt it. Chief of these is the "North Cross Vein" which dips north and shifts the vein several feet west on the north side. There has been much speculation in the past as to what happens to the fissure beyond the Clay Fault, but it has never been found, although the Glenridding Beck exposes the rock right across the line of the lode, and this has been examined countless times, more especially after the Kepple Cove dam burst.

The Greenside Vein

Within the fissure just described occurs the mineralised vein itself. This swings from one joint to another, and sometimes follows the footwall for a considerable distance.

A branch vein goes off to the east some 200 feet north of the North Cross Vein on the upper level, but on the 175 Fm. level, and levels below, this branching does not occur, and it is possible that the two veins, the branch and the main, have come together. The vein filling consists of quartz with mineralised patches to a varying degree of richness, and with hard silicified walls between patches of gouge filling where no quartz or sulphides are ever seen. The walls of the latter patches are soft and rotten. Of the mineralised channels there are three irregular ore shoots, of which the north and south are the most continuous and best defined. The centre one shows a strong development of quartz. These mineralised shoots contain the galena with a small percentage of blende, copper minerals, pyrite, calcite and barytes. On the levels above the lowest adit level, and nearer the outcrop, the galena and other minerals were disseminated throughout the rock and in stringers varying in thickness from a quarter of an inch to two and three inches. Old records show ground stoped out to a width of 50 feet in these areas. In depth, the vein has become more concentrated and the average width of the present stoping is around six feet. The vein has not a uniform dip throughout. It is noticeable, however, that the steeper areas are the most productive, and that an average dip is around 68 degrees.

Mining

Originally, the mine was worked by a series of adit levels, the highest at 2,000 feet, and the lowest, the Lucy Tongue Level, at 1,000 feet above sea level.

The last mentioned level was begun in 1845 on a vein known as the Lucy Tongue Vein, which runs parallel with the strike of the Greenside Vein, but to the south east, and driving was continued on its course until the South Cross-course or Clay Vein already mentioned was intersected. In view of the fact that this cross-course was known to cut the Greenside Vein, the level was turned and driven on it for a considerable distance. The bearing of the level, however, became too westerly for the ore-producing zone proved in the upper levels, and the direction was again changed to the north to come under the productive ground. Consequently, the last portion of this level is in country rock.

Eighteen years were occupied in the driving of this level, the distance being just over one mile, and its entire length was drilled by hand.

A further 2,500 feet of exploratory driving has been done on the Lucy Level along the Greenside Vein 1,500 feet of this has been carried out within the last ten years in barren lode. The 1,000 feet developed by the old Greenside Company was stoped in places to a width of between 40 and 50 feet.

On finding that the lode continued in depth, a vertical shaft was sunk by the old Greenside Company from the Lucy Level at a distance of one mile from the mouth of the adit. The shaft is rectangular in shape, 13 ft. x 9 ft. in size, and has three compartments, two for hoisting, and one for a ladderway. It is connected to the Lucy Level by a cross-cut 7 feet high by 9 feet wide, and is 96 feet from the lode in the hanging wall. It intersects the lode at a depth of 270 feet, and is continued to a depth of 540 feet. The shaft is known as Smiths, and the bottom is the 90 Fm. level. Three intermediate levels were opened out from this shaft at 40, 60 and 75 fathoms. These are now abandoned.

From the bottom of Smiths Shaft, which is in footwall rock, there is another cross-cut 100 feet in length to the lode.

The lode has been exposed on the 90 Fm. level, 2,200 feet to the north and 900 feet to the south. These workings are now abandoned.

One hundred and twenty feet to the south of Smiths on the 90 Fm. level is the top of an inclined shaft sunk on the dip of the lode. This shaft, which extends down to the 200 Fm. level is known as Murrays. It is 14 ft. by 6 ft. in size and has three compartments, one of which is used as a ladderway. This shaft opened up four levels, the 120 Fm., 135 Fm., 150 Fm., and 175 Fm. Only the 120 Fm. and 175 Fm. are at present being worked.

The 120 Fm. level extends 3,300 feet to the north of Murrays Shaft, and the 175 Fm. 2,500 feet to the north.

At a distance of 1,800 feet north from the bottom of Murrays Shaft, on the 175 Fm. level, there is a vertical three-compartment shaft, which is 7 ft. 6 in. by 11 ft. 6 in. in size extending down to the 217 Fm. level, known as the Internal Shaft. The 217 Fm. level has been driven 800 feet to the south and 450 feet to the north of this shaft.

At the bottom of the shaft the contact between the Andesite and the Skiddaw Slates is exposed.

Power supply

Power is supplied partly by the company's own stations and partly by the North Western Electricity Board.

The company has two hydro-electric generating stations, with an output of 250 kilowatts. The energy is generated by impulse turbines directly connected with alternators working at 2,200 volts. The grid supply was connected in 1937 and is transmitted 9 miles by underground cable, and 3 miles overhead. To this installation the company contributed £15,000.

For underground power, two cables are laid along the Lucy Adit and the voltage is stepped down underground to 650 volts. Power for the mill is stepped down to 440 volts. Lighting, both underground and on the surface, is at 110 volts.

The output from the company's stations varies according to the weather conditions and the amount of water available, and during a favourable period they will provide 80 per cent, of the mine's requirements.

Drawings and Photographs accompanying the article