The Herd Dome (Pipe (Breccia)) occurrence is underlain by well-layered volcanic rocks of the Lower Jurassic Telkwa Formation (Hazelton Group). Reddish brown coloured basalts are the most abundant rock type and comprise massive flows, breccia, tuffs and fragmentals. Three areas have been identified within the central part of the property which contain copper mineralization. These are the Pipe, Onucki and Bragg Lake zones (093L 178).
At the Pipe zone, exposures of andesitic or dacitic flow rocks are typically fragmental, brecciated or tuffaceous in appearance. They are stained by malachite and azurite and contain varying amounts of chalcopyrite and pyrite as veinlets and disseminations. Bornite, covellite and chalcocite have also been identified. The hostrock is albite-quartz-chlorite-pyrite altered dacitic porphyry or a dacitic coarse lapilli tuff or breccia. Chip and panel sampling of one mineralized outcrop yielded 0.55 per cent copper and 12 grams per tonne silver over an interval of 6 metres (Assessment Report 22542, page 9).
Significant copper mineralization extends over at least 150 metres, but does not approach the intensity seen in the featured outcropping, which was blasted open by earlier workers, except as isolated blocks in talus. The strong homogenizing alteration appears to extend well beyond obvious mineralization, though disseminated pyrite is the only pervasive sulphide. The zone was mapped as a rounded pipe by earlier workers.
Copper mineralization near Herd Dome was discovered by Frank Onucki, while prospecting in the 1970’s while employed as a prospector by El Paso Mining & Milling Co. but no claims were staked at that time.
In 1980 and 1981, Mr. Onucki staked five claim blocks to cover the known mineralized area.
In 1980, Onucki returned to the area and staked claims to cover the mineralization. The following year he discovered chalcopyrite, bornite, covellite and minor amounts of chalcocite in silicified volcanic breccias and fragmental rocks which he interpreted to be a breccia pipe. These claims were allowed to lapse in 1983. No additional exploration was conducted in the area until 1991, when Mr. Onucki re-staked the area. Since 1991, five work programs have been conducted on the Herd Dome property. Field work to 1997 consisted of prospecting, geologic mapping and the collection of approximately 200 rock chip samples.
The property remained dormant until 1993 when Donegal Development optioned the claims from Mr. Onucki. Donegal then entered into an agreement with Iron Lady Resources, which later changed its name to Takepoint Ventures. During 1995, the Placer Dome camp site was reclaimed
A 1997 exploration program by Takepoint Ventures Ltd was done in order to further delineate the areas of known mineralization, map related structures and lithologies where possible, and define additional drill sites. Field work consisted of developing a temporary camp, rock chip sampling and geologic mapping. Thirty-six rock samples were collected.
In 2008, Cadillac Mining personnel carried out a field assessment of the property to identify the geological context, examine the main showings and to obtain samples of mineralization. In addition, five stream sediment samples were taken on creeks that drain the periphery of the property.
In 2009, an Aster satellite image (obtained in 2006), was used for alteration study based on reflected light spectrum. The image’s multi-spectral qualities were manipulated using specific algorithms to identify areas with reflective spectrum consistent with those produced by: Iron Oxide (FeO), Silica, Sericite, Hydroxide, and Kaolin. Results of this work show weak to spotty responses that coincide generally with the target area, but fail to indicate trends or patterns that might lead to mineralization beyond that which has already been identified.
