The Linda (West) silver-lead-zinc occurrence lies in the upper reaches of Halls Creek, a small tributary west of Frog River, approximately 19 kilometres northeast of Mount Irving in the Stikine Ranges of the Cassiar Mountains (Assessment Reports 16898, Figure 3; 20517, Figure 4).
The occurrence is in a northwest-trending belt of metasedimentary and minor metavolcanic rocks on the northeastern margin of the mid-Cretaceous Thudaka Batholith, possibly a faulted segment of the larger Cassiar Batholith (Geological Survey of Canada Paper 77-1A). The stratified rocks belong mostly to the Upper Proterozoic Ingenika Group of the Cassiar terrane; some Cambro-Ordovician units may be present as well (Geological Survey of Canada Maps 1712A, 1713A). The stratified rocks comprise calcareous and non-calcareous phyllites, schists, limestone and marble and minor greenstone (Geological Survey of Canada Map 42-1962); metamorphic grade is up to greenschist facies.
Locally, the occurrence area is underlain by chloritic phyllite or biotite-sericite schist, and micaceous quartzite of the Swannell Formation. Calcareous phyllite and carbonate of the overlying Tsaydiz Formation may also be present (Assessment Reports 2336, 16898, 20517). Coarse-grained biotite quartz monzonite and granodiorite of the Thudaka Batholith outcrops in the southwest of the property, with a steeply north-dipping contact. Several quartz-porphyry dikes and at least one basic to intermediate sill have been mapped (Assessment Report 16898). The metasediments strike west or northwest and dip moderately to the northeast or southwest due to folding. One vertical, northwest-striking fault and a steep, northeast-striking fault cut the property. The area of interest, which covers approximately 1 square kilometre in the upper reaches of Halls Creek, is centred around the intersection of these two faults. This area has been mineralized, apparently accompanied by pyritic alteration and silicification; subsequent oxidation has produced conspicuous gossans and ferricrete.
Mineralization in the phyllite and quartzite occurs in lenses and fine stringers that are parallel or subparallel to the main fault structures. It consists of argentiferous galena, sphalerite, rhodonite, rhodochrosite and minor chalcopyrite and pyrolusite, in addition to the more widespread pyrite and pyrrhotite (Assessment Reports 2336, 16898). The more substantial sulphides may be massive or a mixture of sulphides and quartzite breccia. There is very little, if any, hydrothermal quartz or gangue quartz (Assessment Report 16898). Locally the galena is smeared out or crushed, indicating later faulting.
The main showings are located on areas of frost-heaved, mineralized boulders or float. Old trenches occur on the former Linda 9 claim (Assessment Report 2336), also designated the West 1 claim (Assessment Report 16898) and the Jackstone 1 claim (Assessment Report 20517). The best material is found in an area measuring 180 metres by 120 metres. A select grab sample assayed 13.22 per cent lead, 7.33 per cent zinc and 120 grams per tonne silver (Assessment Report 2336). Early sampling by Conwest of the high-grade float material, combined with more recent check sampling by Cominco, resulted in the following averages: 569 grams per tonne silver, 29.7 per cent lead, 6.8 per cent zinc and 0.6 per cent copper (Assessment Report 16898). Anomalous gold is also present. Trenching in these zones has revealed the mineralized bedrock, which has also been tested by a few diamond drill holes (Assessment Report 16898). Later sampling, in 1989, of mineralized float boulders (JK-89-1 through JK-89-3 and JK-89-6 through JK-89-9) yielded values of 8.10 to 43.14 per cent lead, 2.30 to 12.46 per cent zinc, 0.44 to 2.67 per cent copper, 201.6 to 942.5 grams per tonne silver and 0.06 to 0.31 gram per tonne gold (Sample JK-89-1; Assessment Report 20517).
A second area of mineralization, comprising a northeast-trending (approximately 056 degrees) fault, probably the dominant structural control, is exposed in the creek to the north-northeast of the main zone, and has similar mineralization, including a 2-metre thick capping of pyrolusite. The quartzite, grit and phyllite here are cut by fractures, which are mineralized with galena, sphalerite, pyrite, rhodochrosite, rhodonite and minor chalcopyrite. High-grade sulphides occur at fracture intersections. There is a reference to early work (done by Lake Expanse in 1952–1953) centred on this creek section, in which channel samples returned assays of 20.6 grams per tonne silver, 2.1 per cent lead and 1.3 per cent zinc over 8.2 metres, and 10.3 grams per tonne silver, 1.2 per cent lead and 0.7 per cent zinc over 87 metres (Assessment Report 16898). The channel samples appear to have been done along, not across, the mineralized fault.
A third area of mineralization is exposed in outcrop to the east of the Main zone and comprises abundant black sphalerite with anomalous indium and tin values. In 1990, two grab samples (Q5525 and Q5531) from this zone yielded 1.67 and 0.61 per cent copper, 5.62 and 10.20 per cent lead, 7.79 and 16.85 per cent zinc, 0.007 and 0.011 per cent Indium, respectively, with 0.012 per cent tin each (Assessment Report 20517).
Elsewhere in the occurrence area, sparse pyrite and galena occur in disseminations or in laminae in silicified sericite-biotite schist.
Work History
In 1952 and 1953, Lake Expanse is reported to have examined the area and completed a program of geochemical (soil and silt) sampling, limited geophysical (gravity, magnetometer and electromagnetic [VLF, IP]) surveys and minor drilling and hand trenching.
In 1962, Conwest Exploration Co. Ltd. completed a 11.0 line-kilometre ground electromagnetic survey on the area as the West group of claims. Trenches of an unknown date are reported to have been identified at this time. In 1969, Quebec Cartier Mines completed a program of geological mapping and soil sampling on the area as the Linda and West claims. The following year, a 12.9 line-kilometre induced polarization survey was completed. In 1979 and 1980, Cominco Ltd. competed ground electromagnetic and gravity surveys on the West group of claims.
In 1987, Skylark Resources Ltd. completed a program of geological mapping, rock sampling and a 1.2 line-kilometre ground electromagnetic (VLF) survey on the area as the West 1 claim. In 1989 and 1990, Formosa Resources Corp. prospected the area as the Jackstone 1-5 claims. In 1994, a program of geological mapping, stream silt sampling, rock sampling and prospecting was completed. In 1995, C. Graf completed a minor program of prospecting, geological mapping and silt sampling on the area as the Gorf property.
In 2022, Bonanza Mining Corporation conducted a Geophysical Induced Polarization (I.P) Survey over the Frog property.
