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Wicklow – Mountain -Building in Seven Easy Stages.
This stage spotlights the rocks surrounding the Vale of Avoca, which developed as part of a chain of volcanic islands on the Iapetus Ocean floor. Imagine an explosive eruption where the ashes fall into the surrounding sea and are then disturbed by storms or seismic activity. The ashes would move down slope as turbidity currents and then spread out over considerable areas of the deeper seafloor. The eruptions on Montserrat in the Caribbean during the 1990’s were probably similar in scale and impact. hot circling water beneath Avoca’s seafloor dissolved metals from its surroundings and, when convected back to the seafloor, precipitated its metals in those ashes. The Avoca copper deposits formed from such seafloor emissions.
The Vale of Avoca became a popular visitor destination following publication in the early 19th century of Thomas Moore’s (1779-1852) familiar ballad, “The Meeting of the Waters”.
This was not the first time, however, that this district came to public attention, because little more than a decade earlier, a remarkable gold rush took place in the valley to southwest of Woodenbridge. Between diggers and spectators, perhaps thousands were present some days. But talk of national good fortune was premature and most of the readily accessible lucrative deposits were exhausted, without valuable bedrock source being discovered. Nevertheless, its fame was such that the popular Irish playwright, John O’Keeffe (1747-1833) produced a successful play on the West London stage, ‘The Lad o’ the Hills’, based on events surrounding it.
The sharp moves in financial markets and subsequent 25% increase in the price of gold since the start of the year has seen an unprecedented rush to gold and gold stocks as safe havens
Excerpts from a brief history of metal mining in the Vale of Avoca, County Wicklow – by Alan Thomas and Peadar McArdle – Published by IMC Exploration (IMCP)
Continued – Modern Mining in the Vale of Avoca (1958-1982)
Avoca Mines Limited, after some refurbishment of the existing plant and using the more modern, low profile mining equipment, continued to develop and extract the ore from the West Avoca underground workings. This led to the mine being deepened and a new underground crusher and conveyor being installed to improve productivity. Ore was mined from two main ore bodies: South Lode and Pond Lode. Improved stoping methods developed at the mine at this time enabled greater output to be achieved from the two ore bodies than had previously been possible. One of the techniques developed here has since become known internationally as the Avoca Method. The company also mined ore from open pits at East and West Avoca.
The spoil heaps from 18th and 19th century mining were re-treated using the modern processing techniques which made a better recovery of copper possible. What had been thrown aside as waste in the past was now capable, using these modern techniques, of being transformed into a saleable product. Sadly history was to repeat itself and in spite of financial support from the Government, the company once again was forced into receivership on 6 August 1982. Once the underground pumps were switched off the mine started to fill with water and is now completely flooded. Thus ended another chapter in the centuries old metal mining history of the Vale of Avoca.
To be continued,….
Modern Mining in the Vale of Avoca (1958-1982)
Mining in the Avoca Valley between 1958-1982 relied for the greater part on underground trackless mining – extracting large tonnages of lower grade ore in the West Avoca area at Ballygahan and Ballymurtagh. Open pit mining was mostly from the east side of the river at Tigroney and Cronebane. From 1958-1962 St Patrick’s Copper Mines Ltd was responsible for the introduction of the relatively new trackless method of underground mining which enabled larger tonnages to be mined and consequently lower grades could be economically extracted. This entailed driving an inclined tunnel from surface down at a gradient of 1 in 8 to gain access to the ore body. Simultaneously a steeper tunnel driven from surface to an underground crusher station was put in to house a series of four conveyor belts which took the crushed ore from the underground storage bins under the crusher station and conveyed it to the surface.
Then it went to the mill ore storage bins. Ore from these surface bins fed the newly constructed ore processing plant or mill as it is known. This mill was capable of handling 4000 tonnes of ore per day. Once in the mill the ore was treated as it was in the 19th century but using modern equipment; it was further reduced in size, screened, washed and crushed to a fine powder. Each stage produced a separation of higher grade from waste material. The difference being that now none of these operations was done by hand, but by large electrically driven machines. The use of chemical reagents was also a 20th century innovation as flotation of the ore to cause the needed separation was aided by the addition of a variety of reagents, depending on the impurities which had to be separated from the copper concentrate.
To be continued….
The Vale of Avoca is a beautiful part of County Wicklow, deservedly know as the “Garden of Ireland”. It features on the earliest known map of Ireland by the geographer Ptolemy who is said to have visited the area in 150AD. The mineral wealth of the valley has been known for centuries and prominent people have been involved in its exploration. Among the most celebrated, (although not the most successful), was the 19th century nationalist leader Charles Stuart Parnell, who was said to be obsessed by exploration progress.
An eminent geologist Sir William Smyth visiting the area in 1853 wrote of his impressions.
“There is perhaps no tract in these islands which exhibits, even to the uninitiated, an appearance so strongly stamped with the characteristics of the presence of metallic minerals. For a considerable distance on both sides of the deeply cut valley of the Avoca the face of nature appears changed and instead of the grassy or wooded slopes, or the grey rocks which beautify the rest if its course, we see a broken surface of chasms. ridges and hillocks, glowing with tints of bright red and brown, or assuming shades of yellow or livid green, which the boldest artist would scarcely dare to transfer to his canvas.”
“Here and there from among the ruins peers the white stack and house of a steam engine; or water wheels stand boldly projected against the hillside, some still neglected, others whirling around in full activity; long iron pump rods ascend the acclivities to do their work at distinct shafts, and as long as the daylight lasts, the rattle of chains for raising the ore, and the clink of the separating hammers attest the vigour of the operations. In truth quite independently of the geological or mining interest of the place, a walk through this series of mines, especially on a sunny evening, will yield a harvest of novel and striking scenes, the effect partly of the features of the mineral ground and partly the fine distant prospects which the higher workings command.”
Today the beauty of the valley has reached a much wider audience, due in no small way to the success of the BBC TV series ‘Ballykissangel’ which was filmed on location in Avoca.
To be continued….