Broadview Zone
The Broadview deposit is at 1920 metres elevation on the east slope of Great Northern Mountain. It is at the head of Broadview Creek, a minor tributary that flows to the east into Ferguson Creek approximately 2.5 km north of Ferguson. The Broadview (L.1550) tenure is one of several crown-granted mineral claims that straddles the border between NTS Mapsheets 82K/11 and 82K/12. The tenure cluster also covers the Blue Bell [082KNW060], Great Northern [082KNW061], St. Elmo [082KNW062] and True Fissure [082KNW030] mineral occurrences. The latter is to the northwest, of the Broadview, across Broadview Creek. The Broadview Group was originally known as the Great Northern Group and/or the Alpha Group.
Click on the following links: Broadview 1 and Broadview 2 to see typical pictures of the gold-bearing massive sulfide ore found at surface).
The Lillooet, Fraser River and Cariboo Gold Fields Company Limited worked on the property between 1895 and 1897. No further work was reported until 1905, when it was bonded by a local syndicate. In September 1906, the Broadview was acquired by Ohio Mines Development Company Limited and small-scale, intermittent operations were carried on by the company, or lessees, until 1909. At that time, the developments appear to have comprised 150 metres of tunnel in 5 adits between elevations of 1680 and 1800 metres, a 30-metres deep shaft, and, on the Old Sonoma claim, a shaft with 18-metres of drift. The Ohio Mines Development Company Limited shipped 66 tonnes of hand picked ore containing 1.71 grams per tonne gold, 1371 grams per tonne silver and 38 per cent lead from the upper shaft in 1909 and 1910 (GSC MEM 161).
Comara Mining & Milling Company, Limited acquired 21 claims, including the Broadview and True Fissure, in 1946. The combined property was then passed to Columbia Metals Corporation, on its incorporation, in March 1949. The land package was later extended to 43 claims. In 1955, Yellowknife Bear Mines Limited drilled four diamond drill holes, totaling 457 metres, from surface. However, control of the property reverted to Columbia Metals the following year. In 1968, an induced polarization survey was carried out and considerable drilling was done from the No. 3 level in an attempt to find parallel veins. A further five holes were drilled adjacent to the Broadview shaft in 1972, but two were abandoned before their target depths. The remaining three intersected a mineralized quartz-carbonate zone in the footwall of one of the old stopes.
The Broadview mine is south of the Broadview Fault. The area is underlain by grits and black phyllites of the middle division of the Broadview Formation. The rocks are broken and cut by numerous shears and faults that strike in a variety of different directions. The rocks are injected and cemented by lenses and veins of quartz with a minor amount of carbonate, mainly ankerite. Diamond drill core shows that there is abundant vein quartz over an interval of 122 metres but the greatest concentration is in the central part of the section. Massive quartz and ankerite is well exposed in the shafts, between the Nos. 2 and 3 adits and in the outer part of No. 4 level and may form a more or less continuous vein. However, the area lacks the well defined continuity of shear zone and gouge found at the True Fissure [082KNW030] mine. It is a broad zone of recurrent fracturing and veining that has a strike of 160 degrees and dips at 70 degrees to the northeast. The zone can be traced for a surface distance of 300 metres and an elevation difference of 100 metres. It has a fairly well defined hanging wall and a diffuse footwall. Within it, there are numerous large and small veins, some of which are mineralized.
The main ore shoot lies in the plane of the structure and pitches at approximately 45 degrees to the northwest. It is exposed at 1830 metres elevation in the Broadview shaft, which was sunk 36.5 metres on a shoot of coarse-grained galena-sphalerite-chalcopyrite-pyrite ore in a weathered and sintery, honeycombed vein of milky quartz and ankerite. The shoot appears to follow the footwall of a tight fissure near the middle of the vein. It is 5.5 metres long and 1.52 metres wide on the 60-foot level and has been mined from that level to surface, and for a short distance below. The galena ore was hand picked and the sphalerite and chalcopyrite rich ore was left on the dump. There is an open-cut besides the No. 1 adit that exposes mineralized stringers in quartz veins in silicified green phyllite. The adit itself cuts sheared phyllite for 24 metres and intersects a ragged quartz-carbonate vein that strikes 120 degrees and dips steeply to the northeast. A short winze has been sunk from the adit to explore sulphides found in the footwall of the vein. This vein has been referred to as the "Copper" vein by Emmens and others. The No. 2 adit is 67 metres long and follows a sulphide-rich shoot that is 10 metres long and approximately 0.6 metre wide. A sample across 0.51 metre of the best-looking material assayed 0.34 grams per tonne gold, 253.7 grams per tonne silver, 4.09 per cent copper, 5.83 per cent lead and 4.5 per cent zinc. The shoot follows a tight fissure that has a 171 degree strike and 70 degree dip to the east. There are other smatterings of mineralization elsewhere in the adit. Adit No. 3 is 7.6 metres long but appears to be largely unmineralized. There are reported to be pockets or shoots of sulphide in the No. 4 and No. 5 adits; however, they were inaccessible in 1962, and are not described by Fyles and Eastwood (EMPR BULL 45). The two working on the Old Sonoma crown grant, immediately to the south of the Broadview, were worked at the same time as those of the Broadview and they show a similar style of mineralization. They encountered quartz-carbonate vein material with disseminated sulphide and rare pockets of higher grade sulphide.
Columbia Metals Corporation Limited controlled the True Fissure, Great Northern and Broadview properties in the mid 1960s and conducted an induced polarization survey that suggested that the True Fissure vein could be traced onto the Broadview claim. In 1968, the company undertook a substantial diamond drill program on the No. 3 level in an attempt to find parallel veins or splits.
The Broadview Zone is the Most Southern Massive Sulfide Occurrence
- The Broadview Zone was the first zone discovered at Thor, and had significant drifting completed in the early 1900's
- In contrast to the other zones found at Thor, the Broadview Zone is copper dominated.