Porto Rico Mine, Barrett Creek, Ymir, Nelson Mining Division, British Columbia, Canadai

Regional Level Types
Porto Rico Mine	Mine
Barrett Creek	- not defined -
Ymir	- not defined -
Nelson Mining Division	Division
British Columbia	Province
Canada	Country

The Porto Rico Mine is located near the headwaters of Barrett Creek, west of the Salmo (a.k.a. Salmon in old literature) River, about 9 kilometres west-northwest of the settlement of Ymir, or 20 kilometres south of Nelson, British Columbia, in the Nelson Mining Division.
There is a short description of the property, including regional geology, on the British Columbia “Minfile” site, current to 1991. A portion relative to geology is quoted below:
“The area is underlain by basaltic to andesitic lapilli tuff and pyroclastics (Unit Je3) of the Lower Jurassic Elise Formation, Rossland Group (Open File 1989-11 [Høy and Andrew, 1989]). These are intruded by the Late to Middle (?) Jurassic Mammoth Intrusions comprising plagioclase augite porphyritic diorite (?).
The occurrence consists of a quartz-filled fissure that strikes northeast and dips about 45 degrees to the northwest. The host rock is comprised of an augite porphyry sill which intrudes andesitic volcanics. The quartz vein averages about 0.8 metre in width and hosts pyrite, gold, arsenopyrite and very minor galena, sphalerite and chalcopyrite.”
Giles Peatfield comments:
The Porto Rico Mine is a small past producing gold and silver mine, with simple geology and mineralogy. I have chosen to present it because it has early reports of tungsten minerals, which have not been confirmed by later work. This review includes information regarding the adjacent Spotted Horse deposit (British Columbia “Minfile” occurrence number 082FSW 190), which was worked on a vein considered to be an extension of the Porto Rico structure.
This property (Porto Rico and Spotted Horse) is of interest because early reports say that there were occurrences of the relatively uncommon secondary tungsten mineral tungstite here; see the comment below in the mineral section. Tungstite was encountered at the Kootenay Queen Mine, in the Sheep Creek Camp near Salmo, British Columbia (Walker, 1909), about 25 kilometres to the south-east. See Mindat occurrence “Kootenay Belle Mine, Salmo, Nelson Mining Division, British Columbia, Canada.”
The Porto Rico Mine was mined in a modest way, discontinuously between 1897 and 1946, with a small cleanup of dump material in 1969, producing gold (the principal product) and silver, as well as very small amounts of copper, lead and zinc. Of this, most of the tonnage was milled on site, with a lesser amount shipped to a smelter, probably the CM&S facility at Trail, British Columbia. Official figures on the British Columbia “Minfile” site show that the total ore mined amounted to 5,740 tonnes (6,327 tons), yielding 178,470 grams (5,738 troy ounces) gold; 46,405 grams (1,492 troy ounces) silver; 322 kilograms (710 pounds) copper; 138 kilograms (304 pounds) lead; and 51 kilograms (112 pounds) zinc. Production from the Spotted Horse vein, between 1901 and 1937, was reported as a very modest 47 tonnes (51 tons) yielding 2,083 grams (67 troy ounces) silver and 1,649 grams (53 troy ounces) gold. Tungsten, although reportedly present, was not apparently commercially produced from either vein.
Giles Peatfield comments on the minerals reported:
Given the number of different workers and the time frame involved, I have chosen to comment on all the minerals so far reported at this property.
Arsenopyrite: McConnell (1899) reported “mispickel” from the Porto Rico vein.
Calcite: Reported by Drysdale (1917) and no doubt seen by others.
Chalcopyrite: Reported by McConnell (1899). No subsequent writer reported the mineral, but given that there was minor copper production from the Porto Rico vein, it is considered likely that it occurs here.
Galena?: There are no reports of identification of galena here, but if present it would account for the small amount of lead produced from the ore. I would regard it as probably present.
Gold: Free gold was reported in the quartz veins by Drysdale (1917) and by Galloway (1932).
Limonite?: Drysdale (1917) reported that there was weathered pyrite, with “red iron oxide.” I think it most likely that this was limonite or a related mineral.
Pyrite: Reported by several workers; McConnell (1899) used the old name “pyrites.”
Pyrrhotite: Reported only by McConnell (1899), but not by any later workers.
Quartz: This is the main vein mineral, reported by all workers.
Scheelite: Mulligan (1952) and Little (1960) both commented that scheelite “had been reported” at Porto Rico, but gave no details as to where they got this information. I would regard the presence of scheelite here as tentative but possible.
Sphalerite?: There are no reports of identification of sphalerite here, but if present it would account for the small amount of zinc produced from the ore. I would regard it as probably present.
Tungstite?: Walker (1909) wrote that “The Porto Rico mine, a few miles north of Ymir, on the Great Northern railway, when operated some years ago was said to have shown considerable quantities of tungstite on the concentrating tables. Unfortunately as the mine is not now operating I have not been able to confirm this report.” Stevenson (1943) wrote that “At the Porto Rico, approximately 5 miles northwesterly from Ymir, tungstite was reported to Walker (VI, 1909, p. 38) to have been found on the concentrating tables. It has also been reported (H. C. Hughes, personal communication) from the Spotted Horse approximately 1 mile north-easterly from the Porto Rico.” This is the sum total of what I have been able to find regarding these putative identifications; note that they are based on hearsay evidence rather than direct identification by the authors in question, thus leading to my regarding the presence of tungstite at these localities as tentative. Note also that Sahama (1981) made the point that absent “valid mineral characterization” the designation “tungstite” is problematic. He stated that “It seems likely that some specimens labeled tungstite in the collections are actually fine powdery ferri-tungstite (alumotungstite) [both discredited, now varieties of hydrokenoelsmoreite – see Mindat mineral species listing], hydrotungstite, etc.” The details of mineralogy of tungsten ochres are complex and beyond the scope of this review.
Giles Peatfield comments on the rock types reported:
All these rock names were reported by Drysdale (1917), except for sandstone which was reported by Mulligan (1952), and tuff, reported by Høy and Andrew (1989). Drysdale named the basic intrusive rock “augite-feldspar porphyry”; I have arbitrarily called this diorite, following the wording in the “Minfile” description. Note that kersantite is a variety of lamprophyre – see Jackson, 1997.

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Link to British Columbia Minfile:	082FSW189

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References