The Shamrock (L.416) prospect is located on the eastern shore of Loughborough Inlet between Shamrock and Poison creeks. The occurrence encompasses three, pre-1900 adits called the Shamrock, Shamrock Extension and Inlet showings. The Shamrock adit is reportedly located 150 metres east of a small bay and at an elevation of approximately 90 metres; the Island adit is located approximately 280 metres to the south-southwest of the Shamrock adit and the Shamrock Extension is located approximately 380 metres to the south- south east of the Shamrock adit.

The Loughborough Inlet area is underlain by northwest elongated intrusive rocks, principally diorite to granodiorite, of the Jurassic to Cretaceous Coast Plutonic Complex. Long narrow belts of metasedimentary and metavolcanic rocks are contained within the intrusives. Recent exploration has identified a previously undiscovered belt on and around the Shamrock (L.416) prospect. Here, the meta- sedimentary and metavolcanic rocks are correlated with the Upper Triassic Karmutsen Formation. These rocks form a belt, 250 metres wide, which consists of parallel 50 metre wide argillite-limestone-chlorite schist bands separated by a 150 metre wide transitional zone of diorite. The belt strikes 130 to 140 degrees and has been traced for approximately 1 kilometre.

Locally, an aplite-related pyroxene-rich skarn system hosts sulphide mineralization consisting of pyrite, pyrrhotite and chalcopyrite developed as narrow seams and lenses or as disseminations within fractured, chloritized argillite. Each adit was driven to test fractured, pyritized, limonite- stained schist developed at the contact with diorite.

It was reported in the Geological Survey of Canada Memoir 23 that samples from the workings returned gold values of up to 17 dollars per tonne. This represents a value of 20.568 grams per tonne gold based on a price of 25 dollars per ounce in 1913.

In 1987, a grab sample from the dump of the Shamrock adit assayed 3.0248 per cent copper, 44.7 grams per tonne silver, and 0.0408 per cent zinc (Assessment Report 17161). Gold was not detected in the sample, possibly due to a high detection level of 3 grams per tonne.

In the late 1800’s, Cuba Silver Mining carried out extensive prospecting and tunnelling, totalling 90 metres, on the Shamrock claims. In 1986 and 1987, Stina Resources completed programs of geological mapping and rock, silt and soil sampling on the area. In 2004, Interactive Exploration completed a program of rock sampling, geological mapping and an 8.2 line-kilometre combined ground electromagnetic and magnetic survey.