The Holy Cross epithermal precious metal occurrence is located on the east side of Holy Cross Mountain, northwest of Bentzi Lake, approximately 33 kilometres south of Fraser Lake and 145 kilometres west of Prince George.
The area of interest includes a large part of the now-lapsed HC claim group, a focus area of exploration by Noranda Exploration Company Limited between 1988 and 1989. The claims covered gold anomalies defined by rock chip samples of silica-flooded rhyolite. Exploration by Noranda included geochemical surveys, magnetometer and induced polarization surveys, geological mapping and the excavation of 26 trenches. There is no record of exploration prior to Noranda activity.
The oldest rocks exposed in the area are dull green intermediate volcanics of the Middle Jurassic Hazelton Group. They occur along the north-facing slopes and low-lying areas to the north. Lithologies include reworked andesitic crystal tuffs and plagioclase-phyric flows. These rocks have been thermally metamorphosed to a fine grained, mottled pale pink and green rock with relict plagioclase phenocrysts, where they are intruded by a biotite quartz monzonite plug. The salmon-coloured, medium-grained intrusion contains from 3 to 4 per cent weakly chloritized biotite. It might be correlative with the Jura-Cretaceous Francois Lake Suite of intrusions that crops out predominantly to the north of the area. Grey chert pebble conglomerates (Cretaceous Skeena Group equivalents) overlie Jurassic Hazelton Group rocks. Locally, they are weakly silicified and cut by veinlets of quartz-pyrite. The conglomerates are in turn overlain by pale grey-green hornblende phyric dacite to andesite flows that might be correlative with the Cretaceous Kasalka Group.
Maroon to cream-coloured, hematite-stained and variably argillically altered plagioclase phyric andesite to dacite flows, flow-banded rhyolites, rhyolite breccias, and associated felsic to intermediate lapilli and crystal tuffs unconformably overlie all older rock units. These rocks are considered part of the Ootsa Lake Group. The flow-banded rhyolite forms a ridge that trends to the northwest across the area. This unit appears to be part intrusive and part extrusive; it cuts all older stratified rocks in the area and in part overlies the argillically altered andesite flows. It is interpreted as part of a flow dome complex. Three northwest trending rhyolite domes outcrop between Bentzi Lake and the peak of Holy Cross Mountain.
Epithermal-style mineralization occurs in several areas of the property, all of which are hosted by altered Ootsa Lake Group rocks. The Holy Cross property has been identified as a potential low-sulphidation epithermal-style gold-silver deposit. Gold and silver mineralization is most often associated with banded vuggy quartz veinlets and silicified volcanic rocks. The best gold values came from trench 1 (TR-1) at the main showing area. Within TR-1, banded pyritic quartz-jasper veins up to 10 centimetres wide occur at an intersection of two linear features trending at approximately 35 and 120 degrees. These veins contain 10 to 15 per cent disseminated pyrite within quartz and massive grey chalcedony and have an intense silicification alteration halo that extends for tens of metres. Manganese, limonite and hematite typically coat fracture surfaces in the massive grey crystalline silica.
In 1988, an 8.5-metre section of brecciated and intensely silicified rhyolite with 1 to 2 per cent very fine grained disseminated pyrite averaged 0.51 gram per tonne gold and 4.3 grams per tonne silver (Assessment Report 17807). A 2-metre interval graded 2.64 grams per tonne gold and 9.7 grams per tonne silver (Assessment Report 17807). Manganese, limonite and hematite typically coat fracture surfaces in the massive grey crystalline silica. A sample of silicified rhyolite with drusy quartz veins collected and analyzed in 1988 returned 7.12 grams per tonne gold and 4.8 grams per tonne silver (Assessment Report 19005). In 1989, sampling of trench 1 yielded up to 1.0 gram per tonne gold over 8.5 metres (Assessment Report 19627). In 1995, four samples (54048 to 54081) from trench 1 yielded an average of 1.798 grams per tonne gold over 4.0 metres. A single grab sample (54084) of banded quartz with chalcedony yielded 9.56 grams per tonne gold (Assessment Report 24228). Two grab samples collected in 1996 from an outcrop of altered pyritic rhyolite located on the western grid returned values of 416 and 1460 parts per billion gold (Assessment Report 24732). In 2001, a trench sample (RR19) of vitrified rhyolite with disseminated pyrite assayed 24.02 grams per tonne gold and 20.8 grams per tonne silver (Assessment Report 26946).
Other anomalous areas (i.e., Trench 17) contain banded hematitic and/or comb quartz veins and stockworks hosted by flow-banded rhyolite. Barren or weakly anomalous quartz-stockwork zones are commonly associated with weakly to moderately argillically altered wallrock, reflecting a less intense, possibly more protracted event. Sulphide mineralization in these areas is very weak or absent. Pervasive hematitic alteration has stained andesites and rhyolites dark maroon or purple. Sulphidization appears to be a post-hematite event and has resulted in the development of up to 4 per cent disseminated cubic pyrite euhedra. Pyrite cubes are commonly enveloped by bleached zones one to three times the size of the pyrite grain.
Sparse copper mineralization, consisting of trace to 1 per cent chalcopyrite in quartz-carbonate veinlets, is hosted in Hazelton Group volcanics. The mineralization might be genetically related to the biotite quartz monzonite intrusion; however, chalcopyrite also occurs in quartz-carbonate veins in younger rocks spatially unrelated to the quartz monzonite.
In 1987, the discovery of visible gold in a sample collected from a rhyolite dome and several other samples with anomalous gold concentrations during a reconnaissance exploration program in the area led to Noranda Exploration Company Limited staking the first Holy Cross claims. Major exploration began the following year with the establishment of 105.7 line-kilometres of grid and the collection of 3170 soil samples from the Holy Cross grid, 1953 soil samples from the PB grid, 26 stream silt samples and 467 grab samples from outcrop and float. Assay results from the soil samples were mapped and several zones of anomalous copper, silver and gold were identified. The best results from the grab samples were obtained from silicified rhyolite and rhyolite breccias. Stream silt samples did not return any anomalous values. In addition, nine bulldozer trenches were excavated down to bedrock and magnetic geophysical surveys were conducted over the Holy Cross and PB grids. Follow-up exploration in 1989 consisted of geological and geochemical surveys and induced polarization and magnetic geophysical surveys. In total, 770 rock samples and 1137 soil samples were collected and analyzed. Anomalous gold values were generally found to occur within larger zones of anomalous copper and silver values. Seventeen trenches were excavated over a variety of geological, geochemical and geophysical targets. After 1989, Noranda ceased exploration and allowed the claims to be forfeited.
The claims were restaked simultaneously by Kennecott Canada Limited and Cogema Resources Incorporated in 1994, sparking a claim dispute. Kennecott eventually conceded the claims to Cogema but prior to this completed geological mapping and geochemical surveys on the property. Later in 1994, Cogema carried out a limited exploration program of geological mapping and geochemical surveying. In 1995, Cogema optioned the property to Phelps Dodge Corporation of Canada Limited, who conducted a limited exploration program of prospecting and geological mapping that same year. In 1996, exploration efforts focused on detailing an east-trending gold soil anomaly identified by Noranda during the 1988 field season. That year, exploration consisted of establishing 6.6 kilometres of new grid and collecting 101 soil samples. Two samples were collected off the grid at sites sampled by Noranda in 1988 to verify historic data. In addition, Phelps Dodge also carried out prospecting, geological mapping and rock sampling (53 samples) of the Zur 5 claim. Results from the soil sampling delineated two notable gold anomalies on the property. In 1997, Phelps Dodge continued the exploration program with geological mapping, prospecting and rock sampling (18 samples). No new areas of mineralization were identified, no further work was recommended and the property was returned to Cogema. Cogema continued to hold the claims until they lapsed in 1999.
In 2000, Geoffrey Goodall staked claims over the key showings. The property was optioned to Tuscany Minerals Limited, who hired Goodall to conduct a rock geochemical sampling program in 2000 and 2001. Tuscany later returned the property to Goodall in 2002, when Bard Ventures Limited optioned the property and announced the intention to undertake a detailed exploration program to identify potential drill targets, though there is no record of such work having been completed before the claims were allowed to lapse in 2005. The claims were later acquired by L. Erdman and sold in 2006 to Aegean Marine Consultants Limited, a private company wholly owned by Goodall.
Golden Cross Resources Incorporated acquired the property from Aegean in 2006 and conducted a preliminary exploration program of excavator trenching, geochemical sampling within and adjacent to targets previously explored by Noranda and the partial establishment of a grid for use in future exploration. The following year, linecutting was completed on the grid and induced polarization (IP) and magnetic geophysical surveys were completed over the entire grid area. Several resistivity and chargeability anomalies were defined at the periphery of the grid, prompting a follow-up program of grid expansion and additional induced polarization and magnetic surveying to be carried out in 2009. In 2009, an additional 7.5-line kilometres were cut, extending the grid to the south and the west. Drilling was recommended to evaluate the geophysical targets, however, this was not undertaken and the claims were allowed to lapse.
In April 2014, the initial claims comprising the Holy Cross property were staked by Charles Greig to partially cover the areas of the main mineral occurrences and trenches. Additional claims expanded the property in 2015 and 2016. In 2015, a desktop study was done comprising a compilation of all exploration data from the area of the Holy Cross property, including exploration assessment reports, as well as government sponsored geological mapping, airborne geophysical survey data and MINFILE reports. GIS software was used to combine all the data, along with satellite imagery, to facilitate an evaluation of the relationships between known mineral occurrences and geological, geochemical, geophysical and topographic features. Based on the relationships noted in the mineralized areas, recommendations for further exploration on the rest of the property were formulated. Later in 2015, an IP survey, totalling 4.8 kilometres on two lines, was undertaken in the Hilltop zone, to overlap and extend previous survey lines to the west and to depth. A near-surface, flat lying high resistivity feature was observed and shows good correlation with the mapped rhyolitic unit. Four discrete chargeability anomalies were noted at moderate depths, two of which coincide with elevated copper and gold soil geochemistry. Additional IP survey lines were recommended to better define the zones between, and along trend from the wide-spaced 2015 survey lines.
In 2016, a program consisted of soil geochemical sampling in the western part of the Holy Cross property to test an area along the projection of the northwest trending resistivity high and the possible extension of the rhyolite unit (57 samples were collected on two northeast-oriented lines).