The area is underlain mainly by Paleozoic rocks of the Eagle Bay assemblage and Fennell Formation. The Eagle Bay assemblage comprises Early Cambrian to Mississippian metasedimentary and metavolcanic rocks that are locally intruded by Devonian orthogneiss. The Fennell Formation (Slide Mountain Group) comprises Devonian to Permian oceanic rocks which were tectonically emplaced over Mississippian rocks of the Eagle Bay assemblage. The Fennell and Eagle Bay rocks were deformed and metamorphosed together; the metamorphic grade is lower greenschist through most of the area, but increases sharply to amphibolite facies in places. The Fennell and Eagle Bay successions are cut by mid-Cretaceous granitic rocks of the Raft and Baldy batholiths, and by Early Tertiary quartz feldspar porphyry, basalt and lamprophyre dikes. They are locally overlain by Eocene sedimentary and volcanic rocks of the Kamloops Group and by Miocene plateau lavas.
A thick pile of massive to pillowed basalts with local pods and layers of cherty tuff and greywacke comprise the lower part of the Fennell Formation in the Chu Chua area. Stratigraphically upward these give way to massive basalt, then through a transitional zone of basalt, chert, phyllite, quartz feldspar porphyry and intraformational chert conglomerate into overlying phyllites and turbiditic sandstones of the Eagle Bay assemblage. Rocks of the Fennell Formation are generally not highly foliated. The schistosity, where developed, is axial planar to early, generally northeast plunging isoclinal folds. The schistosity is itself folded about two generations of later folds with generally east and northwest trends. The Chu Chua deposit apparently lies just below the base of the transitional zone (Fieldwork 1979).
The Chu Chua massive cupriferous pyrite deposit occurs within upper Fennell Formation basalts a short distance east of Chu Chua Mountain. The deposit consists of two major and several minor stratiform massive sulphide lenses associated with pyritic cherty rock and lenses of magnetite and magnetite-talc. The two large massive sulphide pods are termed the North and Main lenses, and a smaller pod known as the South lens. The Main and North lenses are within 100 metres of surface. Locally, a lens of massive fine-grained talc underlies one of the main sulphide lenses. The mineralized zone strikes north, dips vertically to steeply west, and is enclosed within pillowed and massive basalts. In general, the deposits plunge steeply to the south and are thickest at surface (up to 50 metres in the Main lens) narrowing with depth.
Recent drilling indicates that mineralization in the Main lens is concentrated in two main areas known as the Footwall zone and the Hanging Wall zone. The Footwall zone is continuous and well developed along the footwall contact of the lens, but is highly variable in thickness. This zone has an average width of approximately 7.2 metres and contains the highest grade mineralization in the deposit. The Hanging Wall zone is thinner, less continuous and lower grade, and averages 4.5 metres in width. The near-surface parts of the deposit are open to the north and south.
The basalts directly east of the mineralized zones are hydrothermally altered to assemblages of mainly talc, carbonate and chlorite, and are locally bleached, silicified and sparsely mineralized; those on the west side are unaltered. The width of the alteration zone in the east ranges from 5 to 25 metres. The alteration pattern suggests that the deposit is proximal and faces west; this facing direction is consistent with top indicators (usually pillows) throughout the Fennell belt of rocks.
The massive sulphide lenses consist predominantly of pyrite with several per cent chalcopyrite and minor amounts of sphalerite. Cubanite, stannite, quartz and calcite are also evident in minor amounts. Chalcopyrite and sphalerite occur within and interstitial to pyrite grains in the massive sulphide sections. The associated magnetite lenses typically contain discrete bodies of pyrite- chalcopyrite but, except near the contacts with massive sulphide bodies, copper grades are usually low. The massive sulphides are also cut by quartz-talc veins, and in one drillhole, by molybdenite stringers. The pyritic cherty rocks which are closely associated with the massive sulphides are generally massive and often brecciated; locally they are finely laminated. These may be chemical precipitates of volcanic exhalative origin. They appear to persist downdip and along strike from the massive sulphides and may, in part, be distal equivalents of the proximal sulphides. Locally, the cherty rocks are cut by pyritic fractures and veinlets carrying chalcopyrite, carbonate-sphalerite-chalcopyrite veinlets, quartz- chalcopyrite-galena veins, and carbonate veins with pockets of pyrrhotite, pyrite and sphalerite. The areas of talc deposition are interpreted to represent the exhalative vents of the mineralizing solutions (Paper 1987-2).
Drilling in 1978 and 1979 outlined indicated reserves of 2 million tonnes grading 2 per cent copper, 0.4 per cent zinc, 0.1 per cent cobalt, 8 grams per tonne silver and 0.4 gram per tonne gold (Paper 1987-2). In the past, Craigmont Mines calculated potential, near-surface indicated reserves of 186,000 tonnes of talc and 476,000 tonnes of magnetite (Property File - International Vestor Resources Ltd., 1988).
Open-pit reserves at Chu Chua are 1,043,165 tonnes grading 2.98 per cent copper, 0.3 per cent zinc, 0.54 gram per tonne gold and 10.2 grams per tonne silver (Canadian Mines Handbook 1992-93, page 203).
In 1977, a regional geochemical survey in the Chu Chua Mountain area under a joint venture agreement between Vestor Explorations Ltd., Seaforth Mines Ltd. and Pacific Cassiar Mines Ltd. (changed Oct. 1978 to Pacific Cassiar Limited) resulted in the discovery of a large anomalous copper gossan. The gossan was subsequently interpreted to be transported and prospecting up the slope eventually located a small gossan with lower but anomalous copper values adjacent to a northerly striking massive magnetite body. The showings were staked as the CC 1-3 claims; subsequent staking was done in the CC 4-11 claims to a total of 150 units. By an August 30, 1978 agreement an 80 per cent interest in the property was optioned to Craigmont Mines Limited. Work by Craigmont during 1978 included a geochemical survey (20 samples) over CC 1, electromagnetic and magnetometer surveys over 25 kilometres covering CC 1-4, and diamond drilling in 23 holes totalling 2843 metres on CC 1 and 4. This work indicated about 2,000,000 tonnes grading 2.0 per cent copper, 0.44 gram per tonne gold, 8.57 grams per tonne silver and 0.4 per cent zinc (Northern Miner - March 15, 1979). In 1979, an additional 2932 metres of drilling was done in 17 holes to further delineate the deposit. Reserve estimates varied from 2 to 4 million tons averaging 2 per cent copper, 0.5 gram per tonne gold, 8 grams per tonne silver, 0.03 per cent cobalt and 0.5 per cent zinc (Pacific Cassiar Limited, Filing Statement 248/80). Further work by Craigmont in 1980-82 included a magnetometer survey over 12 kilometres, electromagnetic surveys over 20 kilometres, a geochemical soil survey (263 samples) and diamond drilling (50 holes to date). In 1982, part-owner Seaforth Mines amalgamated with Quintaine Resources Inc. under the name Quinterra Resources Inc. In 1983, Craigmont attempted to drill several deep holes to test the mineralization at depth but the project was abandoned far short of target depth. In late 1984, Craigmont gave up its option and the property reverted in full to Vestor, Pacific Cassiar and Quinterra (one-third interest each). Reserves in the upper 200 metres of the deposit are an indicated 2,500,000 tonnes at 2 per cent copper, 0.5 per cent zinc, 0.5 gram per tonne gold, 9 grams per tonne silver, 0.05 per cent cobalt together with 180,000 tonnes of talc and 450,000 tonnes of magnetite (George Cross News Letter No.234, 1984). In 1985, Corporation Falconbridge Copper optioned a 50 per cent interest in the property. Extensive geochemical and geophysical surveys outlined several anomalies in an area to the east of the known deposit. The geophysical, geochemical and drilling program begun in 1985 was continued through 1986-87, testing targets in a rhyolite interval separate from the existing reserve. Corporation Falconbridge changed its name in April 1987 to Minnova Inc. In 1988, Minnova tested the open pit potential with 13 short fill-in holes between earlier grid holes. This work outlined an open pit reserve of 712,073 tonnes at 3.1 per cent copper to a depth of 99 metres, 2 per cent copper cutoff and minimum 1.98 metres width. An estimated 471,692 tonnes of magnetite and 149,671 tonnes of talc are potentially available from a shallow pit (George Cross News Letter December 12, 1988). In 1989, Minnova Inc. performed geological mapping, lithogeochemical sampling, 21 holes drilled totalling 1662 metres, 42 kilometres of cut grid and transient electromagnetic surveying. In 1990, Minnova Inc. carried out diamond drilling totalling 1732 metres in 8 holes. In 1991, Minnova Inc. conducted 4240 metres of diamond drilling in 8 holes and also carried out downhole pulse electromagnetic surveys to test the extent of the Chu Chua horizon at depth to the north and south of previous drilling. This drilling intersected a new hangingwall sulphide zone (drillhole CCF-69: 0.97 per cent copper, 0.84 gram per tonne gold over 14.85 metres; and 0.75 per cent copper, 1.37 grams per tonne gold over 4.65 metres). This mineralization occurs at a vertical depth of 365 metres below the surface.
In 2006 Strongbow Exploration Inc. acquired Chu Chua and resumed work on the property including a soil sampling program in the central portion of the claims. They also validated the position of history work and found multi-element relationships between EM conductor and soil anomalies.
In December 2009 Reva Resources Corp. acquired 100 per cent interest in the Chu Chua property and in November 2010 Newport Exploration Ltd. acquired 50 per cent inerest in the property from Reva.
June 2012 Newport Exploration reported an updated inferred resource estimate of 2,506,000 tonnes grading 0.5 gram per tonne Au, 9.4 grams per tonne Ag, 2.0 per cent Cu and 0.4 per cent Zn. Calculated at a cut-off of 1.0 per cent Cu. (Newport Exploration Ltd. News Release June 26, 2012).