The Hidden Valley occurrence is located at the head of Kitsuns Creek, approximately 49 kilometres west-northwest of the community of Smithers.
The Hidden Valley showing is located in an area where Jurassic Bowser Lake Group intermediate volcanic rocks have been intruded by Late Cretaceous to Tertiary Bulkley Plutonic Suite rocks. The Bowser Lake rocks are comprised mainly of basaltic or andesitic tuff breccia and tuff. The volcanics are intruded by pyritiferous monzonite and feldspar porphyry measuring about 2.5 kilometres in length and 1 kilometre in width. Propylitic alteration envelopes an area of about 450 by 600 metres and hosts quartz, calcite and locally, barite veining with chalcopyrite, pyrite and molybdenite.
Alteration around the porphyry intrusion consists of inner sericitic and argillic zones which are marked by an increase of kaolin, sericite, carbonate, and quartz. Molybdenite is more highly concentrated in these zones. The outer propylitic areas are characterized by the presence of epidote, chlorite, and lesser sericite, carbonate, and kaolin.
In 1970, drilling intersected pyrite, chalcopyrite, molybdenite, and some magnetite in quartz and carbonate veinlets and along hairline fractures for the entire length of the 18-metre hole. The overall grade of copper, molybdenum and precious metals are low. In the area of the drillhole the copper-molybdenum ratio was found to be three to one.
Recent work in the area has indicated that a later stage quartz monzonite plug has intruded both the volcanics and the porphyry. Chalcopyrite, molybdenite and pyrite represents early stage mineralization, and galena, sphalerite, arsenopyrite and pyrite accompanied by intense silicification is related to the later stage intrusive activity.
In 1967, Mastodon-Highland Bell Mines staked the property and from 1967 to 1969 conducted geological, geochemical, magnetic and induced polarization (IP) surveys. They also conducted hand trenching and drilled a single diamond-drill hole (182 metres). Pechiney optioned the property in 1970 and drilled an additional seven BQ diamond-drill holes (791 metres) and then two additional BQ holes in 1971 (671 metres), and then returned the property. Results of drilling and trenching indicated low grade copper and molybdenum values in a porphyry system. Results across 30 metres in an old trench averaged 0.58 per cent copper, 0.04 per cent molybdenum and 0.22 gram per tonne gold (Assessment Report 25926). In 1988 and 1989, Kookaburra Gold Corp. conducted geological mapping, rock and soil sampling and identified precious metal values in a number of alteration styles and rock types.
The property remained dormant until Teck’s 1997 program, which consisted of geological mapping and soil/silt sampling. Forty rock and fifty soil samples were collected. In 1998, a program of geological mapping and geochemical sampling was undertaken on the Kit Group of claims. An area covering 6 square kilometres was geologically mapped (1:10,000 scale) and 122 rock samples were collected for analysis. Teck reported extensive alteration is present in a core porphyry system comprised of potassic and carbonate alteration with widespread quartz stockwork and related copper/gold mineralization. Sampling of this central core in 1998 also found high silver and zinc associated with a small sulphide vein in a zone of strong quartz/sulphide stockwork in the intrusive stock. Of more immediate interest were areas of veining that appeared peripheral to the intrusive stock. Several styles of veining are present in both volcanics and sediments. These veins and altered zones contain highly elevated gold, arsenic plus/minus silver, bismuth, copper, antimony, lead and zinc.
In 2010, Argonaut Exploration Inc. drilled nine exploration drillholes totalling 2542 metres from five locations with the deepest drill hole reaching 316 metres. Surface geophysical programs included 13 kilometres of deep penetrating induced polarization and magnetometer surveys. Geological mapping and detailed rock sampling targeted the northern gold zone and the central porphyry system including 171 metres of trenching and 51 metres of stockworked bedrock. Drill core stored on the property from 40 years ago was logged, photographed and sampled adding 1220 metres of core analyses from seven sites to the 2010 field program. A total of 1783 rock and drill core samples are being analyzed as a result of the 2010 field program. Visible molybdenum and chalcopyrite were observed in drill core. Anomalous metals assayed from the core include molybdenum, copper, gold and rhenium. Rhenium values in drillhole HG-10-02 averaged 0.1 gram per tonne for 312.3 metres with interval 3.7 to 6 metres exceeding one gram per tonne. Drillhole HG-10-03 intersected 0.038 per cent molybdenum for 160 metres including 0.118 per cent molybdenum across 30 metres and 0.159 per cent across 16 metres (Press Release – Argonaut Exploration Inc., October 20, November 9, 2010).
