20 IRISH MINERALS AND BUILDING STONES. 



These stratified iron ores of northern Ireland have been described in 

 detail by Mr. Philip Argall,* who was incUned, however, to refer them to 

 volcanic mud-flows, rather than to the products of weathering of the 

 earlier basalts. The richest ore is pisolitic, like that deposited in some 

 recent lakes, and is at times a bright red earthy haematite, at times brown 

 and limonitic, at times, again, black and magnetic, with about lo per cent, 

 of titanium dioxide. The black type of ore, according to published analyses, 

 consists largely of dark haematite ; but some of the granules are formed of 

 magnetite, and even show polarity. The beds are worked between Glenarm 

 and Broughshane, and the actual ore is often a foot in thickness.t 



Intercalated among these interesting strata is bauxite, a hydrous alumi- 

 nium oxide, associated with some pale clay, and giving 

 at times 57 per cent, of alumina on analysis. The 

 isauxite. Irish bauxite is worked, under the name of " alum 



clay," for the manufacture of alum, and was for a time 

 used as a commercial source of the metal aluminium. It occurs both in the 

 Glenarm district and near Ballintoy. Mr. Kinahan states that the alum 

 industry commenced in 1 874, and that beds were worked " more especially 

 near Ballintoy." In 1898, 12,402 tons of bauxite were raised, valued at 

 nearly ;£^3,000; this fell to 5,779 tons in 1900. Antrim furnishes the only 

 record for this material in the United Kingdom. 



The mining of other metalliferous ores in Ireland depends very largely 

 upon the fluctuation of prices in the trades directly concerned. 



Copper, which is practically all in the form of Copper Pyrites, was at one 

 time very profitable, the ore being sent to Swansea 

 _ and Lancashire to be smelted. Chalcosine or Red- 



ttoppe . ruthite (sometimes called in Ireland " grey copper 



ore," a term usually applied to Tetrahedrite), and Ma- 

 lachite, the green carbonate, were also worked on a limited scale. From 1 840 

 to 1843, the annual output of the Ballymurtagh Mine in County Wicklow 

 averaged nearly 6,000 tons of copper ore, while the whole output of copper 

 ore for Ireland in 1899 is recorded as only 533 tons. Development is pro- 

 ceeding in some of the old mining districts of the south, such as the Allihies 

 mine, in County Cork ; but the raising of copper ore has long been con- 

 fined to County Wicklow. In both these counties further prospecting is 

 now in progress. 



Mr. Argall + described the " ancient and recent mining operations " of 

 East Ovoca in 1 879 ; but the best historical accounts of the whole area are 

 to be found in Sir R. Kane's work and in Mr. Kinahan's " Economic 

 Geology." The occurrence of iron pyrites (pyrite) with the copper ore, often 

 in preponderating amount, has led to the same mines being worked for iron, 

 copper, and sulphur, according to the requirements of the day. The pyrite 

 is known as " sulphur ore," and forms the bulk of the material raised at the 

 present time, the output amounting to 2,411 tons in 1899, and 2,434 tons in 

 1900. 



The south of Ireland was in former times essentially a copper-producing 

 district, and the success of the mines at Knockmahon and Bonmahon, in 

 County Waterford, and of the Allihies mine west of Berehaven, in County 



* Journ. R. Geol, Soc. I., vol. vi. (1881), p. g8. 



t See Mem, Geol. Survey to Sheet 20 (1886), pp. 12-16 and 28-31. Bauxite is touched on in 

 the same Memoir ; but its more important application is of later date than 1886. 



J lourn. R. Geol. Soc. I., vol. v., p. 150. See also report by Sir Warington Smyth, Records 

 of the School of Mines, vol. i. (1853), p. 370. 



