The Ashton Copper prospect is located approximately 12.5 kilometres east of Lytton, at an elevation of approximately 1000 metres. The property adjoins and lies directly south of the Nicomen #1 Indian Reservation, which straddles the mouth of Nicomen River, and extends to or slightly beyond the height of land near the southern boundary of the property. The northern boundary of the property is a few hundred metres south of the Trans-Canada Highway and the mainline of the Canadian Pacific Railway. Near the mouth of the Nicomen River, an unmaintained gravel forestry access road twists uphill to the south, bisecting the property and providing access to branch roads that range from driveable to walkable with difficulty.
Regionally, the property straddles the boundary between the older Upper Triassic Mount Lytton Complex on the west side and the younger Lower to Upper Cretaceous Spences Bridge Group on the east, which is split into the Pimainus and Spius Creek formations. The complex is fault bounded, on the west by the Fraser River fault system and on the east by normal faults along the Thompson River. Spences Bridge Group rocks appear to unconformably overly rocks of the older Mount Lytton Complex, which comprises limy volcanics and limy sediments on the east side of the property. Here the Spences Bridge Group consists of an unaltered, upper, reddish-coloured andesitic volcanics and may include locally felsic and mafic flows and pyroclastics along with sandstone, shale and conglomerate beds. A major fault passes through the Spences Bridge Group on the east-central part of the property and may represent the boundary between the Mount Lytton Complex and the Spences Bridge Group (Assessment Report 34483).
Locally, the area is underlain by the Triassic to Jurassic Mount Lytton Complex. On the property, the units of the complex and overlying rocks are described in order of decreasing age. First is a Middle to Late Triassic marble and skarn unit found along road cuts at 1080 metres and 1191 metres. This unit consists of light-grey, crystalline marble. The second unit is likely mid-Triassic and consists of hornblende, pyroxene diorite and gabbro. The third unit is felsite, which may represent feeders to the flows of the Spences Bridge Group, and could be Early Jurassic to Late Cretaceous. The final unit is the Pimainus Formation (Spences Bridge Group), represented by andesite and dacite flows. The grey to brown flows are aphyric to plagiophyric, and locally show platy jointing (Assessment Report 32430). Limestone lenses and calcareous sediments occur in interlayered sediments, epidotized amygdaloidal basalt and unaltered massive basalt of the Spius Creek Formation. The interbedded volcanics and limestone strike 100 to 150 degrees and dip 70 degrees to the southeast to near vertical. On the property, the platy jointing attitudes show that the rocks of the Spences Bridge Group dip gently to the northeast, consistent with the trace of the unexposed contact of the Spences Bridge Group against the underlying rocks. This contact is exposed to within 5 metres on the right bank of Nicomen River a few hundred metres upstream from the Trans-Canada Highway, where it shows no signs of faulting.
At the main 'C' trench, mineralization occurs as disseminated chalcopyrite, magnetite, hematite, malachite and azurite with minor arsenopyrite and bornite. This alteration is found in sheared, north-trending garnet-epidote-chlorite-calcite skarn in limestone lenses. The flows of the Spences Bridge Group are amygdaloidal with quartz, calcite, prehnite and zeolites forming the amygdules. The rocks of the second unit are medium-grained, and where the mafic minerals are altered, they are chloritized with tremolite-actinolite and the plagioclase is epidotized and converted to albite.
In 1969, systematic sampling over 81 metres of trench 'C' yielded an average of 0.19 per cent copper, including 0.73 per cent copper over 10.5 metres (Assessment Report 2532).
In 1970, two grab samples (1104 and 1105) from trench no. 5 yielded 0.10 and 0.16 per cent copper with 16.4 and 9.6 grams per tonne silver, respectively (Property File – 811084 and 811085).
The highest values obtained from sampling in 1993 were from three continuous 1-metre samples taken 150 metres northeast of the 'C' trench. The samples yielded an average of 0.57 per cent copper from a 5-metre wide band of calc-silicate minerals hosting disseminated chalcopyrite and malachite staining (Assessment Report 23116). Significant intersections obtained from reverse circulation percussion drilling in 1993 are shown below (Assessment Report 23495).
-----------------------------------------------------------------Drillhole Interval (metres) Copper (per cent) Host rock 93-1 18.28 0.118 Leucodiorite Including 3.0 0.22 and gabbro 93-2 24.38 0.109 Felsitic diorite Including 3.0 0.18 and gabbro 93-3 15.24 0.1 Limy diorite with quartz veinlets 93-4 9.14 0.1 White diorite Including 6.10 0.127 93-5 6.10 0.194 Limy diorite ------------------------------------------------------------------ |
Copper assay results from Drillholes 93-1 to 93-5, totalling 676.8 metres, averaged 554 parts per million copper (Assessment Report 23495).
Work History
The area has been explored since the mid 1800s, with coarse placer gold being discovered along the Nicoamen River, approximately 2 kilometres to the northwest of the Ashton Copper occurrence, in 1858.
The first work on the Ashton Copper property consisted of a soil geochemical survey for copper by Burgoyne in 1969; the scope of the 1969 survey was extended following the discovery of a copper anomaly. Later that year, a program of geological mapping, rock sampling and 700 metres of trenching in four trenches (A through D) were performed by W. Filipek.
In 1970, Atlas Explorations Ltd. examined the Nicoamen property of Dryad Mines, which is thought to cover the Ashton Copper occurrence.
In 1989 and 1990, 808 Exploration Services Ltd., on the behalf of J.M. Ashton, carried out a 12.5 line-kilometre ground magnetic and very low frequency electromagnetic (VLF-EM) survey over the northern half of the anomalous area as the Rebecca 1-6 claims of the Burgoyne property.
In 1993, Kingston Resources Ltd. completed a program of geological mapping, geochemical (rock and soil) sampling and a 9.9 line-kilometre induced polarization survey on the area as the Rebecca 1-6, Cheryl and Mellisa claims of the Ashton property. Later that year, seven rotary drill holes, totalling 824.7 metres, were completed on the property to test previously identified soil geochemical and induced polarization anomalies.
In 1999, J.M. Ashton and Associates Ltd. completed a program of minor sampling and a 4.2 line-kilometre induced polarization survey. The geophysical survey identified a strong conductivity anomaly at 120 metres below the coincident surface anomalies. In 2001, a 7.9 line-kilometre magnetic survey was completed to extend the survey range. In 2004, a further 1.6 line-kilometre induced polarization survey was completed.
In 2006, arsenic-in-soils geochemical data from a previous survey indicated further anomalies to the south, which revealed anomalous gold pathfinder elements upon further prospecting. This led to a multi-element mobile metal ion (MMI) geochemical survey over two lines to the south of this anomaly. This work was completed by J.M. Ashton. The following year, Houston Minerals Ltd. completed a further program of MMI soil sampling.
In 2009, Sitka Holdings Ltd. completed a 2.1 line-kilometre ground magnetic and self potential survey on the area. In 2011, Sitka completed a program of geological mapping on the Ashton Copper property. The following year, Geotronics Consulting Incorporated, on the behalf of Sitka Holding Ltd., carried out a MMI soil sampling survey consisting of 41 samples along two lines over a length of 1950 metres.
In 2015 and 2017, Geotronics Consulting Incorporated, on the behalf of Sitka Holdings Ltd. and Houston Minerals Inc., completed further programs of MMI soil sampling on the Ashton property. This work identified a large copper-cobalt anomaly, referred to as the Ashton Anomalous zone, striking north-northwest with a minimum strike length of 1500 metres (open in both directions), and a width of up to 1500 metres.
