Porter Claim, Carbon Hill, Wheaton River District, Whitehorse mining district, Yukon, Canadai

Regional Level Types
Porter Claim	Claim
Carbon Hill	Hill
Wheaton River District	Mining District
Whitehorse mining district	Mining District
Yukon	Territory
Canada	Country

The Porter antimony occurrence is located on Carbon Hill, immediately east of the Wheaton River, about 32 kilometres west of Carcross, Yukon.
The following quote is from Yukon Government site “Minfile”- Minfile No. 105D 026:
“Numerous narrow quartz-stibnite veinlets occur mostly within altered granitic rocks of the mid-Cretaceous Carbon Hill Plug on the south and west facing slopes above Antimony Creek. Individual showings are sporadic and consist of pockets of sulphides in quartz-biotite gangue. Both antimony and silver-rich assemblages occur. Stibnite and sphalerite are the most abundant minerals but lesser amounts of galena, tetrahedrite, zinkerite (sic - zinkenite), chalcostibite, plagionite and covellite are also present.
Historic workings, as described in Geological Survey of Canada Memoirs 31 and 234, indicate two areas where exploration activity has been focused in the past; the Porter (Fleming) showing or adit for which this occurrence is named and the Empire showing (veins), approximately 1 km north-northwest of this location, which is apparently the site of the original discovery.
Vein mineralization in the vicinity of the Porter showing is found primarily in three veins. One vein which is exposed in the underground workings and two others which outcrop on surface. The largest of the surface veins is located approximately 100 m east of the adit and has been traced for about 40 m in a series of small outcrops. At its western end where it is exposed in a small pit, it varies in width from 25 to 90 cm and consists mainly of quartz, stibnite and sphalerite with minor malachite. A smaller vein is exposed in a single outcrop, 30 m directly uphill from the adit, where it is 10 to 20 cm wide and is exposed over a length of 7 m. The third vein is exposed underground in the adit and consists of two segement (sic – segments?) each about 3 m in length. Sampling in 1984 returned values of 2 718 g/t Ag, 3.8 g/t Au and 9.1% Sb across 35 cm from the western end of the largest surface vein, 1 678 g/t Ag, 3.7 g/t Au and 8.0% Sb across 15 cm from the underground vein and 2 991 g/t Ag, 0.7 g/t Au and 0.45% Sb across 15 cm from the smaller surface vein.
At the Empire showing at least two veins containing stibnite cut rusty weathering, blue-grey andesite porphyry flows and breccias of Upper Jurassic age. Extensive surface prospecting and trenching has traced the larger vein for approximately 75 m, while the other smaller vein was exposed in only one trench. A chip sample across 48 cm of the footwall portion of the larger vein returned 16.68% Sb.
The 1985 and later work was directed toward the gold potential of the occurrence and adjoining claims. A few widely scattered soil values up to 1 500 ppb Au were obtained, but assays from rocks and drill core were generally low.” From the site as of February 2022.
Further comments on geology and assays. Early geological work by Government geologists can be found in GSC Memoir 31 (Cairnes, 1912) and GSC Memoir 234 (Bostock, 1941). The high silver assays in adit sampling were reported by Wilson (1984).
Comments by Giles Peatfield regarding some of the minerals reported:
Andorite: Mortensen (un-dated) reported andorite as “possible”, occurring as disseminated blebs (0.01 – 0.03 mm) in stibnite. Note that there are now two minerals listed as “andorite” – Andorite-IV (monoclinic) and Andorite VI (orthorhombic), with the same composition (Back, 2018).
Berthierite: Mortensen (un-dated) reported berthierite as disseminated blebs similar to the andorite? mentioned above, and as larger grains (up to 0.2 mm) with inclusions of stibnite.
Chalcopyrite: Price (1949) reported tiny inclusions, presumably ex-solution, in sphalerite.
Chalcostibite: Thompson (1941) identified chalcostibite in polished section. Subsequently, Warren and Thompson (1945) reported that the mineral had been X-ray confirmed.
Covellite: Reported in Yukon Minfile summary, source not stated.
Galena: Reported by Campbell (1965) in specimens said to come from the Porter dump.
Goethite: Reported by Campbell (1965) in specimens said to come from the Porter dump.
Jamesonite: Price (1949) reported “. . . a dull, grey-white metallic mineral, resembling jamesonite.” I would regard this as tentative at best.
Plagionite: Thompson (1941) reported what he thought might be plagionite from the Porter occurrence, and his then supervisor Dr. H. V. Warren arranged to have the material sent to the University of Toronto for study. There it was X-ray confirmed by Nuffield and Peacock (1945), with a pattern very similar to that of material from Harz, Germany. It was subsequently listed in Berry and Thompson (1962). This is one of only three Canadian occurrences of this rare mineral listed at present (February 2022) on Mindat.
Senarmontite: Mortensen (un-dated) reported that senarmontite had been X-ray confirmed; unfortunately it is not completely clear from his report that this is from the Porter occurrence and not from nearby property, but I am prepared to accept it as valid for the locality.
Stibiconite: Campbell (1965) reported for Porter material that “Many of the quartz crystal lined druses have fine acicular yellow crystals of an antimony oxide. X-rays taken of this mineral closely match stibiconite in pattern.” Note that Back (2018) lists stibiconite as a questionable species; see also Mindat mineral species data.
Tetrahedrite: Campbell (1965) reported, from material said to be from the Porter Dump, galena and massive tetrahedrite, of which he reported that “X-rays taken of the tetrahedrite exactly matched the pattern of Argentiferous Tetrahedrite.” This would help to explain the high silver assays noted in the Yukon Minfile quote above.
Tripuhyite : Mortensen (un-dated) reported this mineral as an alteration product of stibnite, which he described as “Identified by X-ray determination.” Again, unfortunately it is not completely clear from his report that this is from the Porter occurrence and not from nearby property, but I am prepared to accept it as valid for the locality.
Zinkenite: Thompson (1941) reported zinkenite “. . . as masses and disseminations in the quartz and fracture fillings in the sphalerite.” It was subsequently reported to be X-ray confirmed by Price (1949) and by Mortensen (un-dated); this material was also listed in Berry and Thompson, (1962). Note that the reports from which the details of mineralogy were taken all used the older spelling “zinckenite”; the spelling used at this time is “zinkenite” – see Back (2018).
Deposit Type(s): Vein Polymetallic Ag-Pb-Zn+/-Au

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Canada Yukon Survey:	12811

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References