The Ann 18 occurrence is situated on the Ann 18 claim, 7 kilometres south of Yedhe Creek, 10 kilometres east of Toad River, in the Muskwa Ranges in the Northern Rocky Mountains approximately 166 kilometres west of Fort Nelson (Assessment Report 3420, Map 14).
The occurrence is in a region known as the Muskwa Anticlinorium, a major north-northwest–trending structure characterized by moderate folding and thrust faulting. The structure consists of Middle Proterozoic (Helikian) rocks of the Muskwa Assemblage, as well as Paleozoic rocks (Geological Survey of Canada Map 1343A; Geological Society of America, Geology of North America, Volume G-2, pages 111, 639). All belong to Ancestral North America (Geological Survey of Canada Map 1713A). Northeast- to northwest-trending Proterozoic diabase dikes are common in the region.
The occurrence area is underlain mainly by the Aida Formation of the Muskwa Assemblage (Geology, Exploration and Mining in British Columbia 1971; Geological Survey of Canada Memoir 373). In this area, this unit comprises calcareous and dolomitic mudstone and slate, silty mudstone, dolostone, limestone and minor quartzite (Assessment Report 3420; Property File - Adamson, R.S., 1971). Bedding strikes northwest and dips moderately southwest. Locally the rocks are folded, sheared and faulted, and are intruded by several northeast-striking diabase dikes.
A prominent shear zone passes through the area, striking approximately 045 degrees. It is approximately 30 metres wide and has been traced for 1.1 kilometres horizontally and 425 metres vertically. Coincident with the shear zone is a large diabase dike, forming a resistant spur. It dips steeply and is between 2 and 12 metres thick. Its contacts are sheared and altered, as is the adjacent slaty mudstone wallrock. The dike and the shear zone are important because they host a discontinuous series of mineralized quartz-carbonate veins, occurring at or close to the dike's contacts in the shear zone. The constituent veins have the same general orientation but may vary in attitude on the local scale. The veins range in thickness from a few centimetres to 2.75 metres; most are under 1 metre thick. They may have originally been a single vein, known as the Neil vein, which has been disrupted by shearing into smaller lenses. The age relationship between the dike's intrusion and the veining is uncertain; at least some shearing post-dates both.
The veins are composed of quartz and ankerite and may have inclusions of wallrock. Chalcopyrite is sporadic and occurs in aggregates and disseminations in variable amounts, along with very minor bornite and pyrite. Secondary malachite and azurite are common. Very locally, there are small blebs and stringers of galena.
This occurrence is centred on the vein in Trench 4, towards the western end of its exposure, immediately west of the Bob group of claims (Assessment Report 3420, Map 14). A related occurrence, the Bob 3-4 prospect (MINFILE 094K 040), is towards the eastern end of the vein. Here, the vein is on the southeast side of the dike. The best chip sample from Trench 4 assayed 2.79 per cent copper over 0.9 metre (Assessment Report 3420, Map 6).
Work History
Exploration in the area dates back to the early 1960s, when copper-bearing quartz-carbonate vein showings were discovered in the Muskwa Anticlinorium. Two showings, Neil Vein (MINFILE 094K 040, this description) and Ann 18 (MINFILE 094K 057, also referred to as the Neil vein), lie within the Neil property of A.R. Raven (ca. 2016). These two occurrences are at the northeast and southwest ends, respectively, of what is believed to the same mineralized vein structure. The veins are referred to by different names. The Neil Vein (MINFILE 094K 040) is also referred to as the Bob 3-4, Ram Creek and Okey Vein, and the Ann 18 vein (MINFILE 094K 057) has also been referred to as the Neil vein.
In 1971, Alberta Copper undertook an exploration program of geological mapping and trenching on the Neil Vein covered by the Bob claims, which comprised their Ram Creek property. In 1971 and 1972, seven holes were diamond drilled on the Ann 17 and 18 claims, totalling 681 metres (Geology, Exploration and Mining in British Columbia 1972). Drilling yielded intercepts including 1.56 per cent copper over 2.4 metres in hole 71-4 and 3.44 per cent copper over 1.5 metres in hole 71-6 (Harrington, E. (2017-12-08): Technical Report on the Muskwa Property). In 1979 and 1980, Halferdahl & Associates Ltd. completed a regional program of soil sampling on the area as the Tuchodi property.
Renewed interest in the property was shown in 1992 (George Cross News Letter, Number 87, May 5).
In 1996 and 1997, Segura Projects Inc. prospected and sampled the area as the Okey property. In 1998 and 1999, assessment work consisting of Landsat TM (optical) and JERS-1(radar) image studies and structural interpretation, was carried out by Crest Geological Consultants. It was concluded that post-mineralization northwest-trending faults may have truncated several veins. If that structural interpretation is correct, there may be several areas in the vicinity of the Eagle (MINFILE 094K 012), Magnum (MINFILE 094K 012), and Neil (MINFILEs 094K 040 and 094) veins that contain more vein structures with accompanying copper mineralization.
In 2002, Senator Minerals Inc. held an option on the property from Seguro and completed a minor program of rock sampling. The following year, Seguro Projects undertook additional rock chip sampling on the Okey claims. In 2005, Seguro optioned the claims that covered the Neil Vein to Action Minerals Inc. At this time some interest in the property was also held by Aries Resource Corp. In that year, Action Minerals undertook very limited rock sampling in the breccia zone at the northeast end of the Neil Vein.
A high-level magnetometer survey of the area was flown by Sanders Geophysics Ltd. in 2005 for Archer Cathro Associates and acquired by Action and Aries, who then contracted McPhar Geosurveys Ltd. and Aeroquest Surveys in 2006 to acquire aeromagnetic and electromagnetic (EM) coverage over their project area which included the Neil property. Interpretations from this data suggest that the mineralized veins in the area parallel the dike trends and that quartz-carbonate veins are nearly always associated with the dike systems.
In 2006, Bradford Mineral Explorations Ltd. conducted 4467.0 line-kilometres airborne magnetic and electromagnetic surveys on the area as the Trident property.
In 2011 and 2012, a program included limited rock sampling, a summary of the airborne magnetic and electromagnetic results and an investigation of iron oxide and hydroxyl alterations using ASTER imagery was completed on the property.
In 2016, a geological remote sensing and structural study was undertaken for A.R. Raven. The study utilized digital elevation models (DEMs), Landsat 7 ETM, ASTER and WorldView2 satellite imagery and was, in part, follow-up work to satellite imagery analysis performed in 2012. The objectives of the study were to provide information on the structural geology and prepare image and base maps suitable for future field work.
In 2017, Fable Copper and Gold Corp. completed a 15.4 line-kilometre ground electromagnetic survey on the Neil property. In 2019, Fable Copper Corp. completed six diamond drill holes, totalling 972.5 metres, on the area as the Neil-Church Key property. Drillhole CK19-05, located on the southwest extension of the Neil vein in the Ann 18 occurrence area, yielded 1.64 per cent copper over 1.54 metres (83.8 to 85.3 metres down-hole; Assessment Report 38953).
In 2021, Fable Copper Corp. completed a program prospecting, rock sampling and UAV photogrammetry surveys on the Church-Key-Neil property. Chip sampling of the Neil vein in the Ann 18 occurrence area yielded an average of 0.76 per cent copper over 9 metres (Assessment Report 39913).