The discovery of an Irish source of rock salt seems to have been somewhat haphazard, as in the early part of the 19th century naturally occurring brine was known in south Antrim and some samples had been recovered by 1839. The slow start seems variously to have been attributed to an emphasis on the importance of coal over salt; the lack of equipment for carrying out systematic testing and perhaps some of the characteristics of the prospectors.
There is no doubt regarding the location of the earliest discovery of rock salt to be exploited but the date has been variously reported. According to Alexander Miscampbell (1894), who later owned the mine, ‘In 1845 the Marquess of Downshire, inspired by the laudable desire of developing the mineral resources of the locality, commenced operations in search of coal about 2 miles north of Carrickfergus in the County of Antrim and a workable seam of rock salt was discovered‘.
Charles Ludlow (1993) reports that the site is indicated on an estate plan of 1848 (as an amendment). About this time the Marquis of Downshire reportedly brought to Ireland a group of shaft sinkers from Wales led by Harry Pickering. The Downshire papers reveal that Pickering was employed as a mining consultant on a number of the Downshire properties in both England and Ireland. His letters to Downshire in the year 1850 provide a rare first hand account of early exploration in the Carrickfergus area. The earliest of the letters, December 1849, refers to a report concerning the coal and ironstone fields of Carrickfergus and Hillsborough in Co. Down, another Downshire estate. By March 1850 work was in progress on a shaft at the latter and by 3rd May Pickering was prepared to bring ‘two steady and good men’ to commence sinking a shaft at Carrickfergus as soon as the necessary gear could be made. His requirements were a windlass, and timber and brick to line the shaft. Although the gear had not arrived at the end of May, Pickering proposed that the men should start work on the shaft. They were to work ‘eight hours round to take advantage of the long days and fine weather’ and to be paid 6d. per day for their labour. Work commenced at the beginning of June. By the 17th Pickering reported that the depth was about thirty six feet and, ‘It cannot be said that coal has not already been found in this shaft as at about twenty four feet deep some lumps of coal was found embedded in the Clay and this proves clearly that it must have been torn from the parent seam.’
According to some observers, there was a suspicion that the coal brought to the surface had been carried into the shaft by the Welshmen and was being produced at timely intervals in order to prolong their profitable contract, as well as ‘a thirst quenching celebration spree to which the Marquis contributed liberally’ (Kerwin, Downshire Papers) . The Marquis seemed oblivious to the deception and made Pickering’s position permanent with a salary, travelling expenses and rent-free accommodation. Pickering had urged Downshire to explore a further part of his estate for salt and in this he was genuinely successful; providing Downshire with the opportunity to give his critics a ‘gentle fright’ at the meeting of the British Association for the Advancement of Science, held in Belfast in 1852. His critics, ‘scientific men’, had ridiculed Downshire for believing that salt and coal could exist on his Carrickfergus property. At least one of these was proved correct, however shortly after Pickering, exposed at last, was dismissed.
Ludlow, C. (1993) A history of salt in Ireland with special reference to the salt manufacturing industry. PhD thesis, QUB.