Mineral Exploration, how it's done

The links below provide information on the most common methods of mineral exploration in Ireland and across the world. Mineral exploration is the process of searching for evidence of any mineralisation hosted in the surrounding rocks. The general principle works by extracting pieces of geological information from several places, and extrapolating this over the larger area to develop a geological picture. Exploration works in stages of increasing sophistication, with cheap, cruder methods implemented at the start, and if the resultant information is economically interesting, this warrants the next, more advanced (and expensive) techniques. However, it is very rare to find sufficiently enriched ore bodies, and so most exploration campaigns stop after the first/couple of stages.Exploration pyramid, showing how after the initial desk study research, each subsequent stage becomes less and less likely. To put into numeric context: In Ireland, despite thousands of prospecting licences, only 3 modern examples of mines have opened since the 1960s.

Geological Mapping

Mapping is the foundation of all geological-related studies, whether it be geotechnical, groundwater, geohazards or mineral exploration etc. It is vital for developing the base-level picture of an area's geology, with each subsequent step of work in an area building off and correlating back to this initial stage. When mapping with a mineral exploration focus, quite often prospecting will be conducted alongside.

Soil Sampling

Soil is composed of several layers, and one in particular 'catches' the metal ions leaking from the underlying rocks, accumulating a mineral-rich horizon. This is the desired layer in soil sampling, from which a 1kg specimen is collected to test the chemistry of the geology beneath. Because of the vast swathes of pasture and woodland in Ireland, this technique is extremely important for collecting data in the countryside where the rocks are blanketed by soil and vegetation.

Stream Sediments

This method works on the principle that sediment material in stream beds is derived from the erosion of the rocks further upstream. Therefore sampling this material in various locations can give clues as to the geology of the upland area, as well as being tested for their chemistry to provide hints as to whether any metals of interest may be hosted within.

Drilling

Drilling is the peak of a mineral exploration campaign. It is an extremely expensive process and so will only be used in the rare locations which have proven considerably interesting for their mineral potential. However, in these few places, drilling provides physical evidence of the rock below, and is used to confirm the theories of the underlying geology which were developed during earlier techniques such as soil sampling etc. Drilling is an essential component of late-stage exploration projects. This page highlights the process of drilling, however the dedicated FAQs section also provides further clarification for any readers with concerns relating to drilling.

Geophysical Methods

Whereas the above methods analyse the chemistry (directly or indirectly) of the geology below surface, geophysics is used to test for the physical properties of the rock. These techniques can offer another side of the story to any geological theories, and so an exploration campaign can quite often compare and collaborate both geochemical and geophysical studies. Described in this page are the processes of magnetic, electromagnetic, electrical resistivity, induced polarisation, seismic and radiometric surveys.

Mineral Exploration in Ireland FAQs

This page answers some of the frequently asked questions surrounding mineral exploration in Ireland. These are suitable for members of the public who are curious about the processes involved, or with concerns about the potential of mineral exploration in their local area, and how this may affect them.