The Brown Jug occurrence is located on a west facing slopes on the eastern side of Hesquiat Lake, approximately 2 kilometres north of Rae Basin.
It has been explored in conjunction with the nearby Thelma (MINFILE 092E 031) occurrence.
In the Hesquiat Lake area, northwest striking limestones and volcanics previously assigned to the Quatsino and Karmutsen formations (Geological Survey of Canada Map 53-17) have more recently been included with the Pennsylvanian to Permian Sicker Group (Geological Survey of Canada Map 1537A). The rocks are intruded by felsic granitic rocks of the Jurassic Island Intrusions (Muchalat Batholith). A dioritic to gabbroic border phase is 500 metres wide.
Locally, at the Brown Jug occurrence magnetite lenses occur "in a highly altered skarn-like rock of volcanic origin, in close proximity to a bed of limestone" (Assessment Report 462). There was believed to be potential for 0.5 to 1.5 million tonnes of 30 to 40 per cent iron (Assessment Report 462, page 10). Unclassified reserves for the Brown Jug are 1 million tonnes grading 35 per cent iron (Assessment Report 462, page 10).
Ministry references and work in the 1980's focused on a polymetallic vein, hosted in sheared interbedded siliceous grit, chert and biotite-quartz rich (tuffaceous?) siltstone. Strong epidote and sericite alteration is present in the wallrock. The vein, traced over 500 metres strikes north-northeast and dips 30 to 55 degrees east. Mineralization is comprised of variable amounts of iron-rich sphalerite with minor amounts of galena, chalcopyrite, pyrite, malachite and cuprite. Arsenopyrite, covellite, pyrrhotite and manganese oxide are reported. Mineralization occurs in a gangue of armenite, a low temperature barium mineral defined in Assessment Report 14694.
In 1982, a composite chip sample (H.L.82-5) of an adit (No. 25) yielded 1.89 per cent copper, 2.48 per cent lead, 4.9 per cent zinc, 824.6 grams per tonne silver and 164.8 grams per tonne gold over 1 metre. Other samples yielded up to 1.84 per cent copper, 3.20 per cent lead and 12.70 per cent zinc (Assessment Report 11159). In 1984, a rock chip sample from a trench (2.5S) assayed 132.4 grams per tonne gold over 0.7 metres. Sampling of Adit 2S yielded 9.9 grams per tonne gold over 3.3 metres (Assessment Report 12380). Diamond drilling, the same year, yielded intercepts of up to 8.03 grams per tonne gold over 2.34 metres; including 24.56 grams per tonne gold and 127.3 grams per tonne silver over 0.54 metres from hole 84-10 (Assessment Report 14694).
In 1962, Paco Resources completed a program of geological mapping and a ground magnetometer survey on the area. In 1982, Cominco completed a program of prospecting and geochemical sampling on the area as the Basin and Lake claims. In 1984, Flower Resources completed a program of geological mapping, soil sampling, trenching, a ground electromagnetic survey and 13 diamond drill holes, totalling 643.2 metres. The drill program explored a strike length of 84 metres and a total down dip extension of 28.5 metres on the structure.
