The Lone Jack occurrence is located on Lone Jack Creek, on the southern slopes of Treasure Mountain. This is on the east side of Jervis Inlet, at Prince of Wales Reach.

Regionally, the area is underlain by a series of northwest-trending volcanic and marine sedimentary rocks of the Lower Cretaceous Gambier Group and argillite, greywacke, wacke and conglomerate turbidites of the Lower to Middle Jurassic Bowen Island Group, which form a roof pendant that has been intruded by diorite and quartz diorite of the Jurassic to Cretaceous Coast Plutonic Complex.

Locally, the host strata comprise a series of fine-grained andesitic volcanic tuffs and flows, and agglomerates with included layers of argillaceous siltstone, chert, limestone and basalt flows. The whole package has been extensively altered by a quartz diorite phase of the Coast Plutonic Complex. Andesitic tuffs and flows comprise approximately 80 volume per cent of all rock types in the area. The argillaceous siltstone occurs as a northwest-trending, moderately to steeply dipping lens 5 to 100 metres wide. Bedding dips 40 to 70 degrees to the west or east.

The main structural features are north to northwest-trending, moderate- to steep-dipping faults, shear zones and fractures. Alteration consists of either propylitic alteration composed of epidote and chlorite or silicification as replacement textures that occur in lenses 5 to 200 metres wide along the andesite-siltstone contact.

Mineralization and alteration at the occurrence are related to the contact between argillaceous siltstone and andesite tuffs and/or flows or shear zones. Two mineralization styles have been observed: 1) pyrrhotite-pyrite-magnetite-hematite-chalcopyrite and/or sphalerite and 2) pyrrhotite-pyrite-chalcopyrite and/or sphalerite. They occur as disseminated to massive sulphide lenses 0.1 to 14.0 centimetres wide in veins, fracture fillings and tension cracks. Mineralization is hosted in a gossan area of 50 square metres on Lone Jack Creek and is fracture controlled.

In 1987, a chip sample (JER87-R16) over 0.5 metre of a volcanic outcrop hosting pyrite and pyrrhotite, located a short distance up the creek from the occurrence, assayed 0.382 per cent molybdenum; another chip sample (JER87-R21) taken over 2.0 metres of a oxidized greenstone hosting pyrrhotite, pyrite and minor chalcopyrite, located up the road a short distance north of the occurrence, yielded 0.197 per cent copper (Assessment Report 18346).

In 1993, a chip sample (R55) taken from a rusty andesite flow containing 5 per cent hematite, 2 per cent pyrite and 2 per cent chalcopyrite yielded 0.17 per cent copper and 2.7 grams per tonne silver over 0.30 metre, and two 0.30-metre chip samples (R39 and R40) of tuff hosting disseminated pyrrhotite, pyrite and chalcopyrite, taken near the road a short distance to the north, yielded 0.17 and 0.19 per cent copper, respectively (Assessment Report 23238). Also at this time, a chip sample (R42) from a contact zone between argillic siltstone and andesitic tuff hosting fracture filling pyrrhotite, sphalerite and pyrite, taken along the creek approximately 300 metres to the northeast, assayed 0.15 per cent copper, 24.90 per cent zinc and 5.5 grams per tonne silver (Assessment Report 23238).

Work History

The area has been historically (1890s to 1920s) explored in conjunction with the nearby Copper (MINFILE 092GNW017) occurrence, and a complete early exploration history can be found there. The Copper Group of claims, which included the Eldorado, Colorado, Portland, Columbia, Beaver, Coon and Otter claims, were originally staked in the late 1890s.

In 1959, Phelps Dodge is reported to have completed a dip-needle survey on the area. In 1965 and 1966, when Gunnex Ltd. conducted a mapping and sampling program of the historical Copper Group occurrences. In 1968 or 1969, Jervis Inlet Mines Limited completed approximately 610 metres of diamond drilling in four holes on the historical Copper Group occurrences.

During 1971 through 1973, El Paso Mining conducted programs of geological mapping, geochemical (rock and soil) sampling, ground magnetometer and VLF-EM surveys and four diamond drill holes, totalling approximately 762 metres, on the area as the T claims.

In 1987 and 1988, Ashworth Explorations Ltd. conducted a program of geological mapping and rock sampling on the area as the Chris, Goliath, Maria, Nita and Orca claims of the Jervis Inlet property.

In 1993, Arrowhead Exploration Services, on the behalf of Anthian Resources Corp., conducted a program of geological mapping, geochemical (rock and soil) sampling and a 10.3 line-kilometre ground magnetic and electromagnetic (VLF) survey on the area as the Treat property.

In 2020, Saxifrage Geological Services Ltd. conducted a minor rock sampling and prospecting survey on the area as the Jervis Inlet Cu-Zn property.