The Eureka occurrence is situated in the centre of the Mount Royal property in the Blue Ridge area, 3.75 kilometres southeast of Mount Brennan and 3.5 kilometres northwest of Mount Jardine on a tributary to Rossiter Creek. This occurrence also includes the old Iron Crown prospect (formerly MINFILE 082KSW149), situated 150 metres to the east.
Three major rock groups are exposed in the area, all of which are intruded by felsic dikes and small stocks related to a Jurassic plutonic event. The oldest rocks belong to the McHardy assemblage of the Upper Mississippian to Pennsylvanian Milford Group and consist of basal limestones and calcareous sandstones overlain by tuffaceous sandstones and conglomerates, in turn overlain by a thick sequence of argillite with minor chert and volcanics. Permian Kaslo Group tholeiitic volcanics with minor interbedded cherty tuff and tuffaceous greenstone and intruded by syn- and postvolcanic diorites conformably overlie the Milford Group sediments and are unconformably overlain by a greenstone conglomerate. Finally, Upper Triassic Slocan Group sequences of argillites are locally interbedded with quartzites and limestones.
Silver-lead-zinc mineralization occurs in the Triassic Slocan Group, locally consisting primarily of black fissile phyllites with interbedded limestone, calcareous phyllites and brown gritty quartzites. The general structural trend is 310 degrees, dipping generally southwesterly. Greenstones and ultramafic rocks of the Permian Kaslo Group unconformably underlie the Slocan Group to the east, also hosting silver-lead-zinc mineralization. Satellite stocks, dikes and sills are generally correlative with the Nelson batholith to the immediate south. Late-stage lamprophyre dikes are also common.
The occurrence is underlain by greenstone and basalt of the Kaslo Group crosscut by quartz porphyry and granitic dikes. Mineralization, consisting primarily of clean galena, is associated with quartz in discontinuous veins lying within a straight, narrow fault-fissure. Pay streaks of galena range from 2 to 5 centimetres in width by 5 centimetres to greater than 15 metres in length.
The property hosts three areas of previous mining activity. The majority of the work appears to be hand-mining activity from the early 1900s. The main working on the property is situated on the western side of the main cirque. The adit entrance is marked by a small ore dump. Underground, the main adit can be followed for approximately 80 metres at 75 degrees before splitting off at a 45-degree angle. Several raises are evident. Surficial examinations of the adit indicate that it follows a structurally controlled shear zone that continues through to the other side of the mountain and into the next valley.
An adit driven for 5.5 metres on the Iron Crown in 1894 intersected a 45-centimetre "orebody".
Early exploration in the area focused on lead and silver ore; however, the discovery of gold in quartz veins led to additional development work. Several adits were driven into felsic dikes or shear zones with associated quartz veining. The Eureka occurrence was an intermittent past producer of silver, lead and gold in 1898, 1937 and 1938. In total, 311 grams of gold, 697.08 kilograms of silver and 166 050 kilograms of lead were produced from 247.66 tonnes of ore (Assessment Report 19475, page 22). The historic Highland-Surprise mine (MINFILE 082KSW037), situated directly west of the Eureka showing, produced 50.29 kilograms (1617 ounces) from 4672 tonnes (5151 tons) of ore grading 10.766 grams per tonne (0.314 ounces per ton) gold (Assessment Report 19475, page i) between 1937 and 1941.
In 1972, Pan Ocean Oils Limited hired Derry, Michener and Booth Limited to conduct a detailed examination of the Nico claims situated to the southwest of the Mount Royal property. Detailed geological mapping was carried out over the accessible portions of the property, but no significant sulphide concentrations were observed.
The ground covering the old Eureka occurrence was examined in 1986 by a joint venture between Havilah Gold Mines Limited and Rawhide Minerals Limited. Work consisted of trenching the vein structure, revealing a mineralized zone greater than 13 metres wide. A channel sample of the vein taken from an old exploration adit 79 metres below the mineralized zone yielded assay values of 16.8 grams per tonne gold (George Cross Newsletter No. 23, February 3, 1986).
Between 1986 and 1988, Abermin Corporation conducted various exploration programs on the Whitewater property, consisting of the Lyle and Whitewater claim groups. The Eureka showing is situated on the border between the former Lyle 1 and Lyle 2 claims. The following year, Prolific Resources Limited optioned the Whitewater property from Abermin Corporation and hired Taiga Consultants Limited to conduct a geological and geochemical exploration program on the Whitewater property. Taiga re-examined felsic dikes and shear zones in the area. A number of old trenches and adits were located. Samples from a number of these dikes and shears yielded low gold and silver values. One of the highest samples from the Prolific Resources Limited 1989 exploration program, BB-33, yielded 0.7 gram per tonne gold and 1.69 grams per tonne silver (Assessment Report 19475).
In 2006, Andrew W. Molnar of Cadre Capital Incorporated staked the Mount Royal claim area. In July 2008, claim owner Andrew Molnar examined the property, conducting prospecting and sampling on the upper portions of the Mount Royal property. Molnar located, photographed and sampled existing adits, trenches and open cuts found on the property. In total, six rock samples were collected and sent for analysis. The most significant results from the 2008 rock sampling program were samples 181873 and 181874, returning 0.53 and 1.36 grams per tonne gold, respectively. Two samples returned greater than 100 grams per tonne silver and 1 per cent lead, with one of those samples returning greater than 1 per cent lead and zinc (Assessment Report 30262, page 13).
In September 2011, Andrew Molnar examined the property again. Molnar conducted prospecting and sampling over various areas in the upper portion of the property and examined historic underground workings that had been inaccessible during the 2008 property examination. Seven rock samples were collected from the cirque area. Three of the seven samples returned anomalous results for gold, silver and copper and five of the seven samples returned highly anomalous results for lead and zinc. Assay results were indicative of a typical polymetallic vein environment. Molnar completed additional physical work on the property in May 2013.
Three samples from the 2011 exploration program returned anomalous results for gold, silver, copper, lead and zinc. Sample 439351, a grab sample collected from 60 metres into the old adit, consisted of banded quartz vein material. Sulphides in the sample were mostly galena with strong limonite alteration material. Assay results returned 0.1093 gram per tonne gold, 0.01526 per cent copper, 0.5643 per cent zinc and greater than 1 per cent lead (Assessment Report 33147, page 15). Sample 439352 was taken along strike of a quartz-veined felsic dike with moderate iron staining on weathered surfaces, minor pyrite in quartz veins and minor hematite staining. Assay results yielded 0.2415 grams per tonne gold, 0.00714 per cent copper, 0.59588 per cent lead and 0.2932 per cent zinc (Assessment Report 33147, page 15). Sample 439357, an 80-centimetre outcrop interval grab sample taken from what appeared to be a caved adit approximately 500 metres south of the main adit, consisted of quartz vein metasediments and fine-grained volcanics with strong bleaching due to silicification and some vuggy sections stained with limonite. The sample was taken approximately 10 metres above the location of the 2008 sample 181870 and returned significantly higher results for gold, copper and lead. Assay results returned 0.7305 gram per tonne gold, 0.02682 per cent copper and 0.19936 per cent lead (Assessment Report 33147, page 15).
