The Rats copper prospect is about 400 metres east of Christian Creek, 12.5 kilometres north-northeast of Princeton.
This area, west of Hayes Creek, north and east of Christian Creek, is underlain by the Eastern volcanic facies of the Upper Triassic Nicola Group, comprising mafic, augite and hornblende porphyritic pyroclastics and flows, and associated alkaline intrusions. These rocks are intruded to the north and east by the Middle Jurassic Osprey Lake batholith. The deposit lies about 900 metres southwest of the batholith.
Copper mineralization is hosted in folded, sheared and altered basalts of the Nicola Group, adjacent to the southwest margin of a zoned stock comprised of diorite and monzonite. Plagioclase porphyritic basalts are the most common type of flow. Plagioclase pyroxene and olivine pyroxene basalts are also noted. Flow banding indicates some isoclinal folding has taken place, with fold axes plunging north. Shearing is widespread, and appears to occur in four distinct directions. Many of the shears are 1 to 10 metres wide and contain abundant gouge, iron oxide and carbonates, including malachite. The basalts are generally well altered, and are replaced by epidote, pink orthoclase, clay, carbonate and limonite. Epidote and orthoclase are commonly fracture controlled and associated with magnetite and sulphides. The degree of alteration varies, and in some places is related to shearing.
Mineralization exposed in numerous trenches consists primarily of malachite, chalcopyrite, pyrite and magnetite, with minor bornite and chalcocite (?). The sulphides are confined largely to a 150-metre wide zone trending west-northwest for 500 metres. This zone is comprised of two parallel subsidiary zones. The southern zone is 450 metres long and 50 metres wide. It contains the strongest copper mineralization, occurring as disseminations, stringers and stockworks. Locally, chalcopyrite and malachite form up to 10 per cent of the rock by volume. The northern zone is 500 metres long and 100 metres wide, and generally contains less 1 per cent chalcopyrite and malachite, mostly as disseminations. The mineralization broadly parallels the folding of the basalts, and therefore may predate it. A chip sample taken across the portal of the adit assayed trace gold, trace silver, 0.67 per cent copper and 0.017 per cent molybdenite over a width of 1.5 metres (Property File - G.E.A. von Rosen, 1971, page 8). A chip sample from a trench southeast of the adit assayed 3.4 grams per tonne silver and 0.17 per cent copper over 51.8 metres (G.E.A. von Rosen, 1971, page 8). A sample of a shear zone analysed 36.8 grams per tonne silver, 3.0 per cent copper and 9.7 per cent zinc (Assessment Report 19165, page 10, sample 89-JCR-6).
This prospect was initially explored by a single adit excavated some time prior to 1969. Amax Exploration completed geological, geophysical and soil geochemical surveys over the deposit between 1969 and 1971. Cop-Ex Mining Corporation conducted 430 metres of diamond drilling in 3 holes and 2400 metres of percussion drilling in 28 holes in 1973, after initially drilling 4 shallow holes in 1971.
Count Fleet Exploration and Co-Pex conducted geochemical sampling, geological mapping, and trenching in the mid 1980's.
No notable work was conducted until 2007, when a contour-oriented mobile metal ion soil survey was undertaken on the Rats mineral claim on behalf of Larry R.W. Sostad. Initial mobile metal ion results indicated a number of locations that were not only anomalous in one or two elements, such as copper and molybdenum, but also in three possible suites of elements:, the Gold Exploration Suite, the Porphyry Pathfinder Suite (partial) and the Base Metal Suite (Assessment Report 30097).
In 2008, Blue River Resources Ltd. acquired the original Castle claims (www.blueriv.com).
In May 2011, a two-person field crew completed 21 line kilometres for nine days of ground magnetometer and very low frequency electromagnetic survey over a portion of the Castle Copper property. Results from the survey showed primary and secondary anomalies (Assessment Report 32480). In the same year, Blue River also completed a diamond drill program totalling 1133 metres over 12 holes. Copper mineralization was intersected in eigth of the 10 holes recovered. Diamond drill hole BXR-11-4 intersected 43 metres grading 0.16 per cent copper from 19 to 60 metres (N MINER, January 12, 2012).
In 2014, small program of rock sampling was completed. Rock samples yielded an average of 0.57 per cent copper with maximum values of 2.2 per cent copper, 38 grams per tonne silver and 0.17 per cent lead (Butler, S.P. (2018-06-08): Technical Report of the Castle Project in BC).
