Katie porphyry copper-gold deposit, Salmo, Nelson Mining Division, British Columbia, Canadai

Regional Level Types
Katie porphyry copper-gold deposit	Deposit
Salmo	Village
Nelson Mining Division	Division
British Columbia	Province
Canada	Country

The Katie porphyry copper deposit is located north-west of Hellroaring Creek, west of the Salmo River, about 6.5 kilometres south-west of Salmo, 28 kilometres east of Trail, and 38 kilometres south of Nelson, British Columbia, in the Nelson Mining Division.
There is an extended description of the property on the British Columbia “Minfile” site, current to 2020, to which interested readers are referred. Relevant portions pertaining to geology are quoted below:
“The Katie claims cover intermediate to mafic flows and tuffs of the Elise Formation. These include andesite to basalt flow breccia, lapilli tuff, crystal tuff and latite fine tuff. Synvolcanic intrusive rocks underlie a large portion of the property and range in composition from monzonite to monzodiorite through to monzogabbro and gabbro. Younger intrusive rocks include feldspar porphyry, rhyolite, lamprophyre and diabase.
Drilling has outlined widespread alkaline porphyry copper-gold mineralization within a 1.75 by 2.5-kilometre area, focused on three zones: Main, West and 17. From 1 per cent to greater than 10 per cent pyrite and chalcopyrite occur as disseminations, fracture fillings and veins associated with contacts between monzodiorite dikes and volcanics. Weathering effects have been noted to a depth of 20 metres or more, with secondary malachite, azurite and local chalcocite. Traces of bornite, pyrrhotite, sphalerite and tetrahedrite have also been noted.
Potassic core zones with copper grades up to 1 percent and gold in the range of 0.5 gram per tonne are characterized by pervasive, vein and stockwork K-feldspar, with biotite, quartz, chlorite and sometimes coarse magnetite grains. These are enveloped by broad areas of propylitic alteration including pervasive and fracture-controlled epidote, chlorite, albite, hematite (goethite) calcite, sericite and magnetite. The potassic and propylitic alteration largely obliterates primary textures, with the exception of feldspar and pyroxene phenocrysts.
Mineralization and alteration are controlled by northwesterly oriented structures and are zoned outward from highest copper and gold in the potassic cores, followed by lower grade values in the propylitic zone. A late stage of mineralization includes strongly deformed quartz-carbonate-sulphide veins within mylonitic shear structures. Sulphides include pyrite, chalcopyrite, tetrahedrite, molybdenite and arsenopyrite. Specular hematite has been tentatively identified.
Katie shows two styles of mineralization: One is an alkalic porphyry copper-gold, and a later shear hosted a gold-silver-copper-antimony-arsenic stage (EMPR Bulletin 109) [Höy and Dunne (2001)].
The Lower Jurassic porphyry mineralization consists mainly of pyrite, lesser chalcopyrite and bornite, and traces of pyrrhotite, sphalerite, tetrahedrite and chalcocite. Sulphides occur both disseminated in hosting volcanic beds or intrusive sills or in veins with quartz, calcite, potash feldspar, chlorite and epidote. Magnetite is widespread except in highly altered potash feldspar zones. Propylitic alteration is mainly a mixture of chlorite, epidote, sericite and actinolite. Local calcite epidote and pyrite stringers cut this zone. Potassic alteration is shown by potash feldspar and secondary biotite. The later shear and mylonites with local enrichment of gold, copper, arsenic and antimony cut the earlier porphyritic mineralization. These shears are either pre-Middle Jurassic or Eocene in age.”
Giles Peatfield comments:
Although probably of marginal economic importance, Katie is interesting from a metallogenic point of view. The deposit has numerous similarities to the so-called alkalic copper-gold porphyries of the British Columbia intermontane belt, e.g. Copper Mountain (Princeton), Afton-Ajax (Kamloops), Mount Milligan (Fort St. James), Red Chris (Stikine area) and many others. Similarities include relatively low amounts of quartz, traces only of molybdenite, and a substantial gold content. Katie’s occurrence in very slightly younger rocks in the south-eastern part of the Province mark it as interesting.
There are no published radiometric dates for the intrusive or volcanic rocks at Katie. Cathro et al. (1993) suggested that the so-called “Katie Intrusions”, which are host for much of the copper-gold mineralization, “. . . were emplaced into the [Elise Formation of the] Rossland Group as synvolcanic intrusions.” Höy and Dunne (2001) wrote that “The age of the Elise Formation is constrained by late Sinemurian fauna in the underlying Archibald Formation and early Toarcian fossils in the Hall Formation. As well, a number of ammonites of Sinemurian age have been discovered in interbedded siltstones and argillites in the lower few hundred metres of the Elise Formation in the Maude Creek area south of Rossland and [in] the Waneta and Fruitvale areas to the east (Little, 1982b). These faunal ages are corroborated by a 197.1±0.5 U-Pb zircon date from an Elise crystal tuff in the Copper Mountain area southwest of Nelson (Höy and Dunne, 1997).”
Regarding mineral resources, Chapman (2006) reported that a block model resource estimate, using “Surpac” software, was performed on data from drilling on the Katie deposit. He provided a series of tables, based on various cut-off grades, for measured, indicated and inferred resources. It is likely that this estimation could be regarded as National Instrument 43-101 compliant. I have chosen to report here the estimates based on a 0.20% Cu cutoff, which are as follows:
Measured: 12,110,518 million tonnes grading 0.324% Cu and 0.342 gram/tonne Au;
Indicated: 26,007,075 million tonnes grading 0.272% Cu and 0.277 gram/tonne Au;
Inferred: 41,279,626 million tonnes grading 0.240% Cu and 0.195 gram/tonne Au.
These results show the Katie deposit to have modest tonnage and relatively low grade.
The Katie porphyry copper prospect is included in the USGS compilation by Singer et al. (2008). Several references are quoted in this report for the deposit; these are included in the present reference list. The information given by Singer et al. (2008) is incomplete.

Giles Peatfield comments on the minerals reported:
The following comments, derived from several reports, give some details of the various minerals reported from the Katie porphyry copper deposit and immediately surrounding area.
Amphibole group: McIntyre and Bradish (1990) described hornblende as a constituent of diorite. Cathro et al. (1993) identified actinolite as a common alteration of pyroxene. Gray (2006) identified both hornblende and actinolite, the latter as fine needles in the groundmass of hornblende porphyry.
Ankerite?: Gray (2006) identified ankerite in a polished slab of a rock that he described as “Glomeroporphyritic Quartz-Monzonite/Trachy-andesite.”
Apatite: Cathro et al. (1993) commented that “Apatite is an accessory mineral in virtually all the Elise volcanic rocks. In tuffs, apatite phenocrysts are often broken . . . .”
Arsenopyrite: Cathro et al. (1993) wrote that “Distinct but relatively minor gold and silver-bearing quartz-dolomite veins with minor pyrite, chalcopyrite, tetrahedrite, arsenopyrite and molybdenite crosscut the porphyry stockwork.” Note that this is the only reference available for dolomite, and the authors provided no specific information.
Azurite: Azurite is a common surface alteration mineral here, reported by numerous workers.
Bornite: This is a common mineral here, reported by most workers as occurring in trace amounts only.
Calcite: This is common here, reported by most workers.
Chalcocite: This is reported by most workers. Cathro et al. (1993) regarded it as “tentative”; Naciuk and Hawkins (1995) reported it as a trace constituent.
Chalcopyrite: This is the principal mineral of economic interest at Katie, reported by all workers.
Chlorite group: Most workers have mentioned “chlorite” or “chloritization”, but none has given specific mineral data.
Dolomite?: See comment above for arsenopyrite and below for tetrahedrite .
Epidote: This is common alteration mineral at Katie, reported by all workers.
Feldspar group: There are numerous references to various feldspar species, including varieties of plagioclase, and potash feldspars, including orthoclase and perthite. As an example, McIntyre and Bradish (1990) wrote that “Potassic alteration occurring near the northern extent of the zone was observed near the bottom of DDH-KT-89-1. It occurs at, and on either side of, the melanocratic diorite-microdiorite contact. K-spar, confirmed by K-feldspar staining, consists of secondary pink wisps of K-spar occurring within quartz veinlets and along fractures and is accompanied by clots of albite. Primary Kspar, more ubiquitous than is evident in hand specimen, is also pervasive in melanocratic diorite and microdiorite samples obtained near the bottom of the hole.” Cathro et al. (1993) noted that “More intermediate [intrusive] phases comprise 15 to 40 per cent plagioclase (An10-45 and 15 to 30 per cent potassium feldspar, including perthite . . . . The abundance of potassium feldspar and perthite is probably due to potassic alteration.” Gray (2006) identified phenocrysts of oligoclase in a thin section of a rock that he described as “Glomeroporphyritic Quartz-Monzonite/Trachy-andesite.”
Galena?: The only reference to this mineral was by McIntyre and Bradish (1990), who in describing two specimens of altered andesitic tuff reported tentative traces of galena?
Goethite?: McIntyre and Bradish (1990), describing one of the breccia types, wrote that “The siliceous breccia contains subangular to rounded fragments composed of silicified aplite, and/or of silica set in a matrix of, in order of abundance, goethite, jarosite, and minor hematite.” Gray (2006) identified, in thin sections, fine stringers of hematite and goethite.
Gold: The report by Epp (1991) was the only reference found with a mention of the presence of native gold. He wrote that “Gold occurs as inclusions with[in] chalcopyrite or [in] fractures in pyrite.” Given the elevated gold concentrations in the mineralized zones, this would not be unexpected, and I would regard the identification as valid.
Hematite: See note above for goethite?
Ilmenite: Cathro et al. (1993) noted ilmenite as a trace accessory associated with magnetite.
Jarosite?: This was reported only by McIntyre and Bradish (1990), with no further specific information. I would regard it as possible but tentative, species not known.
Limonite: Although likely common as a weathering product, limonite was only mentioned specifically by Cathro et al. (1993).
Magnetite: This is a common mineral at Katie, described by most workers. Wells (1994) summarized its occurrence as follows: “Significant fine disseminated magnetite is present in most rock types. In mineralized areas this magnetite may be coarse, up to 1 cm and is secondary.” See also notes for ilmenite and rutile.
Malachite: Malachite is a common surface alteration mineral here, reported by numerous workers.
Mica group: Most workers have noted sericite, as an alteration mineral. Wells (1994) noted that “The alteration associated with the mineralized system is zoned with potassic core zones (k.feldspar and biotite) with significant fracture controlled and disseminated pyrite, chalcopyrite.” and that “Biotite lamprophyre dikes are clearly post mineral and probably Tertiary in age . . . .” A point of some interest is that Gray (2006) described, in an altered intrusive rock, “Green sericite veins (Fuchsite?) – Although green it is not chlorite.” It is not safe to assume that just because a mica is green it is necessarily fuchsite; vanadium can also impart a green colouration to mica.
Molybdenite: See comment above for arsenopyrite. Also reported as “trace” by Naciuk and Hawkins (1995).
Pyrite: Pyrite is common, but according to most workers is sparse and generally fine grained.
Pyrophyllite: Gray (2006), describing a hydrothermally altered trachyandesite [note that Gray’s spelling for this rock tends to be variable] wrote that “Alteration minerals include sericite, pyrophyllite, chlorite, carbonate and epidote.”
Pyroxene group: Wells (1994) noted that some flow rocks were pyroxene phyric but gave no specific data. McIntyre and Bradish (1990) noted that “The [Elise Formation] tuff has been observed to grade into an augite porphyry predominantly in the northwest portion of the grid. The unit is dark green in colour with 1 mm to 3 mm sized phenocrysts of augite or hornblende, locally laths of feldspar may be present, and the matrix is composed of aphanitic feldspars, augite and hornblende.”
Pyrrhotite: Cathro et al. (1993), describing altered intrusive rocks, noted that “Traces of bornite, pyrrhotite, sphalerite and tetrahedrite have been noted and chalcocite has been tentatively identified in drillhole 37.” Naciuk and Hawkins (1995) reiterated this information.
Quartz: This is relatively common at Katie, as a primary constituent of several rock types, and in later veins, as described by McGrath (2011): “At least two styles of quartz veins were recognized on the property. The first group of quartz (+/- calcite) veins appear to be porphyry-related and are wriggly, light grey to white, glassy, and microcrystalline, and the second type are coarsely crystalline, locally cockscomb-textured, brecciated or banded veins that appear to be epithermal in origin.”
Rutile: Cathro et al. (1993), describing a thin section of monzogabbro, wrote “Also note primary magnetite grains (dark grey) with needles of rutile.”
Sphalerite: See note above for pyrrhotite.
Tetrahedrite: Cathro et al. (1993) wrote that “Distinct but relatively minor gold and silver-bearing quartz-dolomite veins with minor pyrite, chalcopyrite, tetrahedrite, arsenopyrite and molybdenite crosscut the porphyry stockwork.” Earlier, McIntyre (1991) had described in logging a quartz-carbonate vein in which he reported “stibnite/tetrahedrite”; there are no other references to stibnite and one is tempted to assume that what he was seeing was fine needles of arsenopyrite. This is suggested by the analytical results for the interval, which include elevated levels of Cu, Ag, Sb and As. Cathro et al. (1993) also noted traces of tetrahedrite in altered porphyry intrusive rocks, as did Naciuk and Hawkins (1995). Note that there are no definitive compositional data; the mineral is presumed to be tetrahedrite, and is the probable source of the reported silver.
Titanite: Cathro et al. (1993) noted “sphene” [titanite] as a trace accessory associated with magnetite.
Giles Peatfield comments on the rock types reported:
These rock names are derived from the several reports used in this review. Some may be alternate names for the same rock type, but I have chosen to list them all. Be aware that in many cases these are field names. For interest, McGrath (2011) presented a series of very good photographs of core specimens of various rock types, which are worth looking at.

Giles Peatfield
BASc. (Geological Engineering) University of British Columbia 1966.
PhD Queen's University at Kingston 1978.
Worked for Texas Gulf Sulphur / Texasgulf Inc. / Kidd Creek Mines - 1966 to 1985.
Vancouver based consultant 1985 to retirement in 2016

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Link to British Columbia Minfile:	082FSW290

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