Mineral Exploration in Ireland

The Republic of Ireland has a notably diverse geology that is prospective for a range of mineral deposits. Large tracts of Ireland are underlain by metasediments and metavolcanics of Proterozoic and Lower Palaeozoic age. These lithologies contain significant volcanogenic massive sulphide (VMS) mineralization (e.g. Avoca, 16 Million tonnes grading 0.6% Cu) and auriferous orogenic quartz veins (e.g. Cavanacaw and Curraghinalt).

The latter style of mineralization has been the focus of extensive exploration efforts across the island of Ireland and in 1999, an opencast gold mine was established at Cavanacaw in Co. Tyrone. The 2014 JORC compliant resource at Cavanacaw is 32,202 ounces grading 7.24g/t Au (Measured), 147,784 ounces grading 6.78g/t Au (Indicated) and 341,123 grading 7.71g/t Au (Inferred)1. Cavanacaw is currently operating as an underground mine.

To the northeast of Cavanacaw, the Curraghinalt deposit in Co. Tyrone has NI 43-101–compliant Measured and Indicated Resource of 3,061,000 ounces grading 15.01g/t Au and an Inferred Resource of 3,038,000 ounces grading 12.24g/t Au2.

In the Ordovician-Silurian Longford-Down terrane the Clontibret deposit in Co. Monaghan has a JORC compliant Indicated Resource of 320,000 ounces and an Inferred Resource of 197,000 ounces (total 517,000 ounces) at an overall grade of 2.0g/t Au3.

The Lower Carboniferous carbonate rocks of the Irish Midlands are host to one of the great ore fields of the world, the ‘Irish Base Metal Province’ (see Figure 4.1). Since 1960, sixteen significant (recorded tonnage4 >1Mt) Zn-Pb deposits have been discovered, including the world-class ore body at Navan (>112Mt grading 9.8% Zn+Pb; Ashton et al., 2016).

Ireland is ranked first in the world in terms of zinc discovered per square kilometre, and second in the world with respect to lead. The high grade, shallow occurrence and clean metallurgy of the ore bodies result in a relatively low cost of mining for the Irish-type Zn-Pb deposits.