The Iron Mask batholith lies in the southern part of the Quesnel Trough, also known as the Nicola Belt. The most important pre-Tertiary rocks in this belt are Upper Triassic volcanic and sedimentary rocks of the Nicola Group. The batholith is a subvolcanic, multiple intrusion which is comagmatic and coeval with the Nicola rocks. It is situated along the southwest side of a regional northwest trending fracture zone and is itself cut by numerous northwesterly faults. The batholith comprises two major northwest trending plutons separated by 6 kilometres of Eocene Kamloops Group volcanic and sedimentary rocks. The Tertiary rocks occupy what appears to be a graben structure resulting from renewed fault movement around the margins of the plutons during Paleocene or Early Eocene time (Bulletin 77). The larger pluton, the 18 kilometre long southern part of the batholith, is called the Iron Mask pluton. The smaller Cherry Creek pluton farther northwest, outcrops on either side of Kamloops Lake. The combined exposure of the batholith, including the intervening younger rocks, is about 33 kilometres long and 5 kilometres wide. Sedimentary and volcanic rocks of the Kamloops Group unconformably overlie the Nicola rocks and the Iron Mask batholith. These include tuffaceous sandstone, siltstone and shale with minor conglomerate, as well as basaltic to andesitic flows and agglomerates with minor dacite, latite and trachyte.
In the vicinity of the batholith, the Nicola Group is dominated by volcanic and volcaniclastic sedimentary rocks. They are generally recognized by albitization of feldspars, occurrence of patchy epidote, and/or rare hematite alteration. On the southwestern flank of the Iron Mask pluton, well-indurated, massive and bedded tuff, breccia and interbedded flows and flow breccia are prominent and are weakly metamorphosed. On the northeast flank, less well-indurated and less altered tuff and tuff breccia predominate. However, adjacent to the intrusive contact, these rocks are also well indurated and epidotized and are locally mineralized with sulphides. At the southeastern tip of the Iron Mask pluton and locally along the southwestern flank, the Nicola rocks comprise distinctive porphyritic augite-hornblende basalt.
The Iron Mask pluton comprises four major, successively emplaced units designated as the Iron Mask Hybrid, Pothook, Sugarloaf and Cherry Creek units. Locally, an additional Picrite unit also occurs which is probably not genetically related to the batholith. The smaller Cherry Creek pluton consists entirely of the Cherry Creek unit. Isotopic dates (194 to 204 Ma +/- 6 Ma) indicate that all of these units are of Late Triassic or earliest Jurassic age (Bulletin 77). The component units (except the Picrite unit) of the multiphase batholith are largely controlled by major systems of northwesterly, northerly and northeasterly trending fractures or faults. Most units show some degree of alteration and/or contamination which may be intense locally. Weak to moderate saussuritization is ubiquitous in all batholithic rocks while potassium feldspathization is more prominent in rocks of the Cherry Creek unit. The units are briefly described in order of oldest to youngest (determined mainly on crosscutting relationships). The Iron Mask Hybrid unit forms the spine of the Iron Mask pluton. It is mostly agmatitic, consisting of rounded to angular fragments of various sizes, texture and composition in a dioritic matrix. The fragments include mainly coarse and fine-grained diorite and coarse-grained gabbro with lesser amounts of medium to coarse-grained hornblendite and scattered xenoliths of Nicola Group volcanic rocks. All rock varieties in the unit contain magnetite which is often more than 10 per cent by volume. Mineralization, particularly of iron and copper, is almost ubiquitous in this unit. The Pothook unit occurs mainly in the northwestern half of the Iron Mask pluton, appearing frequently as narrow, gradational zones between the Iron Mask Hybrid and Cherry Creek units. Rocks of this unit are uniformly of dioritic composition and are medium to coarse grained. The Pothook unit is locally mineralized with copper and iron. The Picrite unit consists of rocks of basaltic composition with abundant clinopyroxene and serpentinized olivine phenocrysts. These rocks generally occur as steeply dipping, poorly exposed and relatively small lenticular bodies in many parts of the batholith. They appear to be associated with recurring, northwesterly trending fracture systems and copper mineralization frequently occurs in their vicinity. Because picrite basalt has been observed far from the two component plutons of the batholith, it is probable that this unit is not part of the batholith. The Sugarloaf unit occurs mainly along the southwest side of the Iron Mask pluton and as small enclosed bodies in the southern half of the pluton. Rocks of this unit are mainly porphyritic with hornblende, minor clinopyroxene and plagioclase in a greyish green matrix. They are of fairly uniform diorite-andesite composition. Several copper occurrences are hosted by the Sugarloaf rocks. The Cherry Creek unit is the most widely distributed phase of the batholith. It constitutes the entire Cherry Creek pluton. The unit consists of rocks with composition ranges from diorite, monzonite, syenite to their porphyritic and fine-grained equivalents as well as local intrusive breccias. Copper and minor iron mineralization is prominent in the Cherry Creek unit, particularly in zones of intense brecciation associated with alkali metasomatism.
The majority of the Python property is underlain by the Iron Mask Hybrid unit. In the northern portion of the property, a 30 to 100 metre wide, southeast trending and west dipping band of picrite basalt is found within the hybrid unit. The hangingwall picrite-diorite contact is demarked by a significant shear zone, known as the Copper Head shear. Three major zones of copper mineralization were identified by previous workers and are known as the Python, Copper Head and Noonday. Copper mineralization consists mainly of chalcopyrite with lesser malachite and azurite.
The Python zone is best described as a breccia pipe zone hosted by norites. The breccia pipe has ill-defined margins and grades into less altered diorite. Copper mineralization is found as fracture fillings and lenses with accompanying low gold values. In the breccia, pink feldspar veins are non-systematic; elsewhere they are wider, more persistent, and tend to adopt one or more distinct attitudes. Where more massive veining occurs, mineralization is purely local and is confined to the immediate vicinity of the pink veins. Epidote, calcite, magnetite and chalcopyrite occur within or at the margins of many veins, either singly or as a varied assemblage of these minerals. In many instances they fill fractures within a vein. The same minerals also occur disseminated in the adjacent altered diorite. The breccia in which the Python mineralized zone occurs probably forms a steeply dipping tabular lens or pipe. In plan it is elongate approximately east-west. Chalcopyrite is essentially the only sulphide present. It occurs as stringers and lenses of varied orientation and as disseminations in the feldspathized diorite. The larger lenses have a thickness of 30 centimetres. In places the ore is vuggy, with calcite, epidote and some fluorite in the cavities. Quartz is virtually lacking. Magnetite lenses, nodules and disseminations are common. Some oxidation of the sulphide to carbonates has occurred. The ore is brecciated and dragged by steep faults striking north-northeast and west-northwest. The northerly faults offset those of the other set with small apparent displacements. A green muddy breccia as much as 30 centimetres wide is commonly present along parts of the faults. Specks of chalcopyrite in the green breccia probably represent mechanically incorporated material. The walls of the breccia are coated with a brown gouge and are polished and slickensided in a manner indicating horizontal and oblique movement, probably subsequent to formation of the breccia. In 1970, estimated reserves of the Python were 199,562 tonnes grading 1.11 per cent copper.
The Lost Chord workings are a short distance east of the Python group but no semblance of the structures seen on the Python group is apparent at these old showings on which work was recorded in 1903 and 1913. Of two short adits, one is southwest of and about 21 metres higher than the other. The upper adit is 1.8 metres long and exposes a steep 10 centimetre wide fault striking 070 degrees and carrying copper carbonates. The lower adit is driven southwestward 6 metres into partly altered diorite. Both north and northwesterly shears occur but are not mineralized. The diorite contains a trace of disseminated chalcopyrite. No pink veins occur in the general vicinity. Bornite was reported in the showings on which there were once a number of opencuts.
The Copper Head zone is a structurally related zone which contains disseminated and fracture filling chalcopyrite mineralization with accompanying gold and minor palladium values. The mineralization is found dominantly within the Copper Head shear and its hangingwall diorites. Locally, mineralization is present within the footwall picrites. The shearing is 1.8 metres wide and has an overall trend of 320 degrees, but in the Copper Head workings it strikes 335 degrees. The dip is 70 degrees or more to the south. The picrite is pulverized within the shear zone, and in the footwall is less broken up but contains some strongly sheared sections. The hangingwall diorite contains pink veins of orthoclase feldspar and is traversed by numerous chloritic fractures. Chalcopyrite is strongly disseminated in the shear zone and in the footwall. Gangue minerals are not abundant. Lenses of calcite and occasionally of tremolite occur, and contain small stringers of chalcopyrite. Small crystals of white fluorite line cavities within the mineralized rock. Little pyrite is present, and little oxidation of the chalcopyrite has occurred. On the hangingwall, diorite contains disseminated chalcopyrite for 30 centimetres or so from the shear zone and at greater distances where brecciated pink veins occur. Several steep faults pass from diorite into the shear zone and apparently displace it. A shallow west-dipping fault cuts the shear zone in the No. 1 crosscut. The greatest width of mineralized shear zone was 7 metres in No. 1 crosscut. In 1980, estimated reserves were 104,316 tonnes grading 1.13 per cent copper.
The Noonday zone is also related to the same sheared picrite-diorite contact as the Copper Head zone. This zone is found along the fault offset picrite-diorite section to the southeast of the Copper Head. The zone contains disseminated and fracture filling chalcopyrite mineralization with accompanying gold and palladium values. In 1972, estimated reserves were 544,260 tonnes grading 0.74 per cent copper, which included 117,923 tonnes grading over 1.0 per cent copper. The Copper Head shear zone between the Copper Head and Noonday zones is also mineralized with disseminated and fracture filling chalcopyrite with accompanying gold and palladium values. Where exposed, the style of mineralization is identical to that of the Copper Head zone. Along strike, to the northwest of the Copper Head zone, in the area of the Orphan Boy shaft (092INE003), the picrite-diorite contact zone is relatively unmineralized.
Across section in the Noonday-Copper Head areas, the footwall diorites are unmineralized while the hangingwall diorites contain minor chalcopyrite mineralization. This mineralization consists of local and discontinuous fracture fillings and disseminations. The exposed Nicola volcanics are well fractured and contain local minor chalcopyrite fracture fillings. In the Jet area, local and discontinuous fracture fillings and disseminations of chalcopyrite are hosted by the hybrid unit. The isolated, small lenses of highly albitized hybrid rocks commonly contain erratic copper mineralization.
The major structures on the property appear to be northwest and north to northeast trending recurring faults which are prominent in the Copper Head-Noonday area. Airphoto lineaments indicate numerous similar trending structures to the south. The Copper Head shear zone, a northwest trending recurring fault, is the best exposed structure. The shear is fairly regular with widths of 1.5 to 6 metres and dips of 16 to 82 degrees to the southwest. It overprints the intercalated diorite-picrite contact. This zone is accompanied by abundant chlorite-saussurite-biotite and carbonate and minor talc and serpentine fracture filling. The shear is poorly to not exposed in the Noonday area and along strike to the southeast. To the northwest, in the Orphan Boy shaft area, the hangingwall diorites display moderate to intense K-feldspar alteration.
Propylitic alteration is ubiquitous. Moderate to intense K-feldspar alteration was noted in the Orphan Boy shaft and Python zone areas. Albitization was observed as extensive patches proximal to the Python zone and as small, discontinuous lenses in the Jet area.
In 1987, BP Resources sampled old core from 14 previously drilled diamond-drill holes to evaluate the potential of the Copper Head and Noonday zones enhancement in gold, palladium and platinum. Generally, there is a rough but erratic correlation between the copper, gold and palladium levels; platinum levels are very low. A 1.8 metre intercept from DDH 78-1 in the Copper Head zone analysed 5.05 grams per tonne palladium, 2.24 grams per tonne gold and 0.55 per cent copper. A 3.6 metre intercept from DDH 72-3 in the Noonday zone analysed 0.62 gram per tonne palladium, 1.2 grams per tonne gold and 0.73 per cent copper. Results from the 1987-88 exploration indicate that significant copper-gold-palladium mineralization is restricted to the sheared picrite-diorite contact zone and its immediate hangingwall and/or footwall. This mineralization has been concentrated within the Copper Head and Noonday zones and their intervening section (Assessment Report 17946).
This property is located on the north slope of Coal Hill, about 5 kilometres southwest of Kamloops. The Python and Noonday claims were the first staked on Coal Hill in August 1896 by Robert Buchanan of Kamloops, and work was begun in sinking a shaft. Ownership of the property in 1897 was given as W.F. Wood and associates. The Python Mining Company, Limited, was incorporated in May 1899 and development work was carried on until 1902. During 1908 the property was under option to W.O. Young and drifting was in progress in one adit. Intermittent work by Mr. Wood and associates was carried out during the period 1909 through 1911. By 1910 the underground workings totalled 327.6 metres in two shafts and an adit. The Granby Consolidated Mining, Smelting and Power Company, Limited, optioned the property in 1916. Some diamond drilling was reported but results are not known. In 1922, the Lost Chord, Python No. 2, Noonday, Copper Head and Python claims (Lots 2561 2565, respectively) were Crown granted to John Beaton, W.W. Wood, J.R. Hall and Susan Wood. No further activity was recorded until 1954 when the property was reported held for a short time by the Canadian Mining and Smelting Company and selected areas of the property were covered by an electromagnetic survey (no record has been found of a company by that name). Makaoo Development Company Limited in 1955 acquired, in consideration of 1,200,000 shares, the 5 Crown-granted claims and 62 located claims and fractional claims in the Jet, Python, Dot, Pie, and other groups. From 1955 to 1963 the company spent in excess of $300,000 on exploration and development work, inclusive of shaft sinking, drifting, crosscutting, diamond drilling, trenching, geological mapping, and geophysical surveys. By an agreement of March 1963 Quamco Limited was granted an option on the property. By an agreement dated February 1964 Quamco Limited assigned its interest in the earlier agreement to Rolling Hills Copper Mines Limited. Rolling Hills at that time acquired an additional 183 recorded claims. Work during 1964 included electromagnetic and induced polarization surveys, and 3616.4 metres of percussion drilling above the Python adit. During 1965 Vanco Explorations Limited held an option on this and a number of adjacent properties. On this property a geochemical survey was made and several drillholes put down to test the resulting anomalies. Rolling Hills resumed work on the property in 1966. During the period 1966 to 1970, inclusive, further geophysical surveys were carried out and drilling totalled 731.5 metres in 5 diamond-drill holes and 1100.3 metres in more than 13 percussion holes. The geochemical and geophysical surveys to 1966 outlined a number of anomalies. Drilling and underground work to 1970 has outlined the following mineralized zones: Python zone, 199,562 tonnes at 1.11 per cent copper; Copper Head zone, 81,639 tonnes at 1.13 per cent copper (R.H. Seraphim, Report 1/05/72 in VSE Statement of Material Facts 4/07/72, Makaoo Development Company Limited). By an agreement dated October 2, 1972, Makaoo granted an option as to Teck Corporation Limited (65 per cent) and Iso Mines Limited (35 per cent) to acquire a share interest in the company. Work by Teck in 1972 included geological mapping, an induced polarization survey over 5.6 line kilometres, a geochemical survey (560 samples), 974.4 metres of surface diamond drilling in 7 holes on the Noonday claim, and percussion drilling in 41 holes totalling 3825.2 metres over various parts of the property. Percussion and minor diamond drilling in the Noonday zone to the end of 1972 indicated 544,260 tonnes of 0.74 per cent copper (C.T. Pasieka, Report 13/07/78 in VSE Statement of Material Facts 6/11/78, Makaoo Development Company Limited). For this work Makaoo issued to Teck 100,000 shares in the company. Teck carried out an induced polarization survey in this vicinity in 1973. The option agreement subsequently expired. In 1976, the property was optioned to a private interest. In 1976, Makaoo Development Co. Ltd. did 243.8 metres of percussion drilling and also diamond drilled seven holes totalling 558.2 metres in the Noonday and Copper Head areas during 1978 and 1979. In 1980, Makaoo completed bulldozer stripping, percussion drilling (amount unknown) on the Python zone and attempted (in vain) to rehabilitate the 2519 adit. Reserves in the Copper Head zone were reported as 104,316 tonnes at 1.13 per cent copper (C.T. Pasieka, 06/06/80, in International Makoo Limited Statement of Material Facts 27/08/80). The company name (Makoo) was changed in January 1980 to International Makoo Limited. In 1987-88, BP Resource Canada Ltd. conducted a field exploration program consisting of underground rehabilitation, geological mapping and rock sampling, diamond drill core analysis (336), grid construction, and soil geochemical sampling (210). The exploration target was economic porphyry-type and/or shear related copper-gold-palladium mineralization. In 1996, three diamond-drill holes were completed on the Jet 7 fraction and Jet 10 claims with attention to emplacement, albitization, fracturing and sulphide showings. No economic copper mineralization was intersected although drillhole number 3 intersected 0.17 per cent copper over 24 metres at depth. In 1999, work by DRC Resources involved geological mapping, surveying, prospecting, reclamation, reviewing previous exploration data and diamond drilling with the emphasis on finding an extension or similar geological setting as that on the Ajax East pit. Three diamond-drill holes totalling 302 metres were drilled on the Jet 7 Fraction adjacent to the Ajax East pit.