The Mining Heritage of the Glendalough Area

The Glendasan and Glendalough Mines – An Introduction

Glendalough is one of Ireland’s most famous heritage sites. Over half a million visitors come here each year to see the monastic remains, view the valley or take walks on the hills.

Few of these visitors realise that Glendalough and the nearby Glendasan valleys were the most important sites for lead mining in Ireland (Map).

Fig. 1. Map of the Glendasan and Glendalough Mines

Lead has been in demand for thousands of years. The Romans used it in plumbing (which takes its name from the Latin name for lead – ‘plumbum’) and it was used for roofing and windows in medieval times. In more recent times lead has been used as a pigment, for solders and for batteries. The main lead mineral in Wicklow is galena (PbS) which often contains small amounts of silver, which could also be economically extracted. At Silvermines in Co. Tipperray there were active lead mines in the 13th Century, but the first reference to lead mining in Wicklow is in the early 19th Century. Lead was first discovered in Glendasan and later these veins were followed through the mountainside to the adjacent valley of Glendalough.

There were three distinct phases to the mining at Glendsan/Glendalough. The first phase was associated with the development of the mines by the Mining Company of Ireland from 1825 until 1890. The second phase was a re-working of the mines and tips by the local Wynne family from 1890-1925. A modern operation between 1948 and 1957, the final phase, concentrated on the development of new workings at depths below old workings in the Glendasan valley.

At the Glendasan and Glendalough lead mines there are remains of this mining landscape which it is hoped can be preserved. There is a wealth of mining heritage remains, including buildings, waterwheel pits, leats and dressing floors. Glendalough and Glendasan valleys are now under the care of the Wicklow Mountains National Park, which cares for the natural flora and fauna and surviving built heritage of the area. The Mining heritage trails are the ‘Mining Walk’ in Glandasan, currently being developed, and the ‘Miners Walk’ in Glendalough.

The Glendasan Mines

The earliest phase of mining, dating from the turn of the 19th Century was when the manager of the Avoca mines, Thomas Weaver was commissioned by the Government to undertake a survey of gold in County Wicklow. Not long after the 1798 Rebellion he discovered a rich vein of lead ore in the Glendasan valley. To develop this Weaver established the Glendalough Mining Company in partnership with local investors. Weaver was responsible for the day-to-day management of the mines.

The Mining Company of Ireland took over operation of the Glendasan mines in 1825 when they bought Weaver’s shares. The price of lead on the open market was always a factor in the running of the mines. Price fluctuations meant that wages also varied over time, the typical boom and bust of mining in general. The Mining Company of Ireland operated their own smelting mill at Ballycorus near Dublin – no smelting was done on the mine site.

When times were good the mining company prospered and invested in buildings, equipment and machinery. A road to the Luganure ore body was constructed in 1826 and on it a railway track, for wagons, was also laid which extended 126 feet into the mine. Dressing floors for separating the ore were built on the site. To extract this ore body ‘The Hero Mine’ was opened initially, to a distance of 30 feet, and ‘The Fox Rock’ mine was opened in 1828. Over the next 10 years, machines for pumping water out of the mines were installed so that lead could still be extracted. There was also a crushing mill erected and a new water wheel replaced horse-power (Fig. 2).

Fig. 2. Glendasan Dressing Plant

‘The Ruplagh Mine’ and a new pump house opened at the site in 1835. An improvement in lead prices in the 1850s resulted in a fresh wave of investment with old workings being re-opened, a new crushing mill erected and machinery brought in. A modern forge was built in the 1870s which saw further advances in machinery and cut the cost of labour. This meant that 2 or 3 boys could now do the work of 9 men.

With the general rise in population, as a result of the mining, came a demand for housing and the Mining Company of Ireland built houses for their work force, believing that both the miners and the company would benefit. Built in the mid 1850s, a row of houses close to the mining works is reputed to have once housed eight musicians. Hence the name… ‘Fiddlers Row’ (Fig. 3).

Fig. 3. Old Photo of Fiddlers Row

The National School system was established in Ireland in 1831. In 1864, The Mining Company of Ireland built a school to provide for the children of their workforce. The ‘Mining School’ operated alongside other National Schools in the Glendalough area.

A very important aspect of mining exploration is the use of timbers to support the tunnels. The shafts and tunnels needed to be propped up as the miners worked their way into the mountain. In the 1850s and 60s The Mining Company of Ireland planted approximately one million trees in the Glendalough Valley for use as timber props in the mines. This was also a commercial venture for the Company as some of the timber was sold on the open market, adding to the company profits.

By the 1850s, 200 men were working above and below ground and 120 tons of lead ore was produced each month (Fig. 4).

Fig. 4 Miners at Glendasan, 1951

As well as working below ground the miners were involved in building the Roman Catholic Church at Laragh. Despite being in the middle of the Famine, the money to build the church was raised and after four years it was opened on St. Kevin’s feast day, the 3rd June 1851. The other major religious denomination – Church of Ireland – was not neglected as some miners contributed to the building costs of St. John’s Church in Laragh in 1843.

As Fr. Mathew, the temperance priest, toured the country in the 1840s preaching the virtues of abstaining from alcohol, the miners also came under his gaze. Some were criticised for their over indulgence. While he was responsible for many people giving up drink, it was still a problem among certain miners. In the 1870s the local Royal Irish Constabulary force was not able to cope with drunk miners who got into brawls on pay day and extra forces had to be called in from Roundwood.

It is probably no surprise that the men drank and played hard as their working day down the mines was anything but easy. The average life expectancy for a miner, at this time, was 42 years. The work was dangerous and the risk of tunnels collapsing was always present. This is exactly what happened in 1825 when two miners were trapped by a rock fall. The accident was not discovered until the next shift change occurred and the men were finally rescued after 33 hours.

For over a hundred years there was no mining in the Glendasan valley until the St. Kevin’s Lead and Zinc Mine was set up by J.B. Wynne, along with other investors in 1948, the third and final phase of mining. A work force of 80 operated it for 9 years. They were divided into two main groups with 55 men employed underground, and 25 men employed in the processing plant and on compressors.

Many men started working in the processing plant at the age of 16. Each shift had four men to operate the plant. The shift supervisor oversaw three others – a man collecting the processed lead from the jig tables (Fig. 5); a man feeding the raw material to the crusher and a third man dumping the rock into the crusher house.

Fig. 5. Miners at Glendasan in 1950’s

Above ground there was also a fitter, a helper and a man for bagging the lead. Many men started work in the processing plant and then discovered that the men underground had much better wages – so they approached their supervisor to get a job down the mine.

When these young men first went underground they worked filling wagons and shovelling ore. They then moved on to helping a driller. Opportunities to drill a few shallow holes with compressed air drills and charge these with explosives followed. Eventually, after a couple of years, they could become drillers themselves. The miners worked in pairs – a driller and a helper – in three, eight-hour shifts per day. There were about four pairs working each shift. Day shift started at 8 a.m. and they drilled 30 holes – each five feet deep – into the face of the rock that would be blasted at lunchtime. After lunch they started filling wagons with the broken rock – usually about 30 wagons of rock from one blast – approximately fifteen tons (Fig. 6).

Fig. 6. 1950’s Processing Plant

In the centre of the rock face was a vein of lead, two to three inches wide, and that was the important area. The remainder was waste.

There were also a number of men filling wagons with ore and extending the rail, air and water pipelines. A blacksmith sharpened drills and tools. Pit ponies worked in the tunnels carting the ore from the mine to the Processing Plant and three men followed the ponies. The compressors and generators ran continuously and there was a man on each shift looking after this machinery to ensure air pressure was adequate at all times. Work in the tunnels was difficult because of flooding and dust from drilling. As a result, many miners developed lung and chest problems.

The two main tunnels in the 1950s were the ‘Fox Rock’ and the ‘Moll Doyle’, driven from the floor of the Glendasan valley. Fox Rock was three quarters of a mile long and the Moll Doyle was less than half a mile long. Lack of money continued to be a problem for St. Kevin’s Lead and Zinc Mine. While sufficient ore was found, the company did not have the technology to process it. A Canadian mining company leased the mines from the Wynnes in 1956.

Given that mining is such a hazardous activity, it is remarkable that there were only three recorded fatalities over the 150-year lifetime of the Glendalough Mines. George Reid was killed in 1864 and Thomas Devlin in 1875. The exact cause of their deaths is unknown. Over 80 years passed until the final fatality occurred on the 22nd of January 1957. Two miners were drilling into the rock when tragedy occurred. Their drill somehow struck a piece of dynamite and an explosion hurled the pair to the ground. Jim Mernagh, a married man with two young children was killed instantly. His co-worker Robbie Carter was seriously injured. (Fig. 7).

Fig. 7 Memorial to Jim Mernagh

The Canadian Mining Company, which had taken over the mines in 1956, was not successful in locating the expected amount of lead and this, along with the fatal accident in January 1957, was the main reason the mines finally closed in the June of that year.

The Glendalough Mines

The Camaderry Mountain separates the two valleys and the two mines – the Glendasan mine and the Glendalough mine. The Luganure mineral vein cuts across Camaderry Mountain between the two valleys. The workings in the Glendasan valley were connected by a tunnel through Camaderry Mountain into Glendalough. This allowed for natural drainage of the Luganure shafts and tunnels and made transportation of the ore for processing in Glendalough valley easier.

Work in the Glendalough valley in the 1850s marked a new location in the exploration of minerals in the area. Construction of a second set of buildings including a water wheel powered-crushing mill was undertaken. Workings further up the Glendalough valley were developed (Fig: 8).

Fig. 8 Overview of Glendalough Mines

The far end of the valley was aptly named ‘Van Diemen’s Land ’ by the miners (after the distant colony of Van Dieman’s land off Australia – now called Tasmania) because it seemed so far away from civilization. Mules were initially used to carry materials up the steep mountainside and bring the ore down. These mules were later replaced by an inclined railway, resulting in greater efficiency and productivity. This tramway brought the ore down from Van Diemen’s Land to the floor of the Glendalough valley for processing.

The 1880s saw a major decline in the fortunes of The Mining Company of Ireland which had experienced losses over several years. The lead was running out in the areas being worked and world prices for lead were in decline. Employment fell dramatically and many of the most experienced miners had emigrated to England and America. Although mining in this valley only lasted for approximately 20 years, mined lead continued to be processed here even into the 1900s.

The Mining Company of Ireland sold the mines to the Wynne family in 1890, denoting a new phase. The Wynnes were an Irish family with previous mining experience in the Avoca and Glenmalure mines. This operation didn’t run too smoothly, however, and after a few years, mining came to a halt due to problems with flooding and a lack of machinery. Needing cash to develop the underground workings, in 1913 the Wynnes set up a water plant in the Glendalough valley to treat the waste from the mines in both the Glendasan valley and Van Diemen’s Land. The waste was transported on a tramway and loaded by hand into a crusher by a mainly female work force. The crushing work continued until 1925 (Fig: 9).

Fig. 9. Glendalough Crusher

The demand for lead during the years of the First World War, 1914 to 1918, brought the Glendalough mines to the attention of the Ministry of Munitions in London which granted aid to the Wynnes to re-open the Fox Rock mines in Glendasan. However, Government financial support was withdrawn at the end of the war. Funds dried up, and so did the mining. This was the last phase of mining in Glendalough.


This article is based on “EXPLORING THE MINING HERITAGE OF COUNTY WICKLOW”,  publicated by the Heritage Office of Wicklow County Council in 2008 based on contributions from the following; Dr. Martin Critchley (Editor), Mining Heritage Trust of Ireland, Marie Merrigan (Avoca), Celtic Copper Heritage, Avoca, Joan Kavanagh (Glendalough/Glendasan), Glendalough Mining Heritage Project Committee Dr. John Morris (Glenmalure), Mining Heritage Trust of Ireland and Dr. Peadar McArdle (Geology), Geological Survey of Ireland.

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