The Lucky prospect occurs along the west bank of Hayes Creek, 0.8 to 1.5 kilometres southwest of the creek's confluence with Christian Creek, and 11 to 12 kilometres northeast of Princeton.
This region, west of Hayes Creek, between Christian and Switchback creeks, is underlain by the Eastern volcanic facies of the Upper Triassic Nicola Group, comprising mafic, augite and hornblende porphyritic pyroclastics and flows. These rocks are intruded to the east, across Hayes Creek, by the Early Jurassic Bromley batholith. About 1 kilometre to the north, north of Christian Creek, they are intruded by the Middle Jurassic Osprey Lake batholith.
The deposit is hosted in andesitic flows, breccias and tuffs, and comagmatic (?) hypabyssal microdiorite dikes and sills, all of the Nicola Group. Some of the microdiorite may represent thick flows. Minor felsite/dacite is also present. Petrographic examinations suggest the andesites may be hydrothermally altered latites and quartz latites (Assessment Report 18863).
The volcanics and intrusives have undergone propylitic and sericitic alteration, within the upper levels of a porphyry hydrothermal system (Assessment Report 6292). Successive zones of propylitic alteration are developed peripheral to a north-trending zone of sulphide mineralization that is truncated to the north by a strike-slip fault. Chloritization of mafic phenocrysts occurs in a zone whose inner margin borders on an area of stronger copper sulphide mineralization. Pervasive epidote occurs in a partially overlapping outer zone, whose inner margin roughly coincides with the outer limit of 1 per cent total sulphide content. Sericite alteration of the volcanics and intrusives is strong but does not appear to be confined to a distinct zone. Minor argillic alteration is also evident. All strongly altered rocks are cut by a post- mineral stockwork of gypsum (selenite) veinlets, 1 to 5 millimetres in diameter.
Mineralization consists primarily of pyrite and chalcopyrite, with minor chalcocite and covellite, and a few grains of bornite. Minor malachite staining is also present. Pyrite/chalcopyrite ratios vary from 100 to 1 in the epidote alteration zone to 5 to 1 in the area of strongest copper mineralization (Assessment Report 6292). Pyrite content increases northward from 1 per cent in the south to 5 per cent at the strike-slip fault. Locally, it occurs in greater concentrations of up to 20 per cent in areas of more intense hydrothermal alteration. The sulphides are largely disseminated. Five to ten per cent of the sulphides occur along fractures near the limit of the pervasive epidote. This increases to 20 per cent in the area of strongest copper mineralization. Chalcopyrite tends to be more strongly controlled by fractures than pyrite.
Copper content varies directly with alteration intensity. Stronger mineralization, containing 0.2 to 0.5 per cent copper, occurs in a zone widening northerly from 75 metres to 250 metres, over a strike length of 400 metres. At this point the zone and peripheral zones of propylitic alteration are inferred to be displaced for at least 400 metres by a right-lateral strike-slip fault striking west-southwest (Assessment Report 6292). One percussion hole, located 70 metres south of the inferred strike-slip fault, analysed 0.42 per cent copper and 0.205 gram per tonne gold over 24.4 metres (Assessment Reports 18863, Figure 3; 20113, page 2, hole RC87-8). A second hole drilled 190 metres north-northwest of hole RC87-8, analysed 0.21 per cent copper and 0.262 gram per tonne gold over 32.0 metres (hole RC87-1). Surface sampling yielded copper values of up to 0.822 per cent and gold values of up to 0.470 gram per tonne (Assessment Report 16265, page 4). Gold values were almost invariably associated with high copper values but many high copper values had low accessory gold. The amount of pyrite in the rock appears to have no bearing on the gold content.
This prospect was initially explored by Kennco Explorations (Western) Ltd. in 1959. The company conducted geological, geophysical and soil geochemical surveys and drilled four holes totalling 227 metres. Quintana Minerals Corporation completed geological and rock geochemical surveys in 1977. Superior Oil Company conducted 233 metres of percussion drilling in 9 holes and 734 metres of diamond drilling in two holes in 1979. The deposit was reassessed for precious metals by Mingold Resources in 1987. The company conducted soil and rock geochemical surveys and drilled 8 holes totalling 717 metres. Total drilling between 1959 and 1987 amounts to 1911 metres in 23 holes.
