Keystone Mine, Coquihalla Pass, Nicola Mining Division, British Columbia, Canadai

Regional Level Types
Keystone Mine	Mine
Coquihalla Pass	Pass
Nicola Mining Division	Division
British Columbia	Province
Canada	Country

"The Keystone mine is located on the west side of the Coldwater River, approximately 6 kilometres north of the Coquihalla Lakes. Base and precious metal mineralization were originally discovered at this locality in the early 1900's and underground development had taken place by 1936. The only production from the mine occurred in 1955, when 81 tonnes of ore were shipped for processing (Minister of Mines Annual Report 1955, page A48). . . Three "vein zones" are known to be hosted along the structure. The No. 1 Vein zone, developed from two levels at the Keystone Mine, comprises quartz, calcite and rhodochrosite with pyrite, sphalerite, galena and rare tetrahedrite. It averages from 5 to 10 centimetres wide, but pinches and swells from a one-centimetre wide pyrite-gouge clay zone to a 30-centimetre wide massive pyrite-quartz vein with minor base metals. It also splits and branches where exposed on the lower level of the mine. A total strike length of approximately 275 metres has been explored, both in underground workings and drill holes. . . Two mineralized intersections averaging one metre in width were encountered in drill holes northeast of and below the mine workings, but precious metal values were very low. A second vein, which assayed 23.25 grams per tonne gold and 41.14 grams per ton silver across a 3.05-metre intercept, was discovered at depth further to the northeast (Assessment Report 19139). Veining intersected in a follow-up hole, however, did not contain significant precious metal values." (Govt. BC).

Collectors visiting the area have two general localities to choose from. The first is typically referred to as Keystone #1, or simply K1, by collectors. This locality consists of the workings (adit, tunnel, etc.) and tailing pile from the No. 1 vein zone. The second area is perhaps a kilometer from K1 and consists of several low piles of rock and debris, as from a test trench. This spot is referred to as Keystone #2, or K2, and likely comes from the exploratory work of the second vein described above in the reference. K2 has limited appeal to collectors, but does produce specimens that are different that those from K1. The minerals of interest are massive blue Celestine, as well as nice crystals of pyrite and sphalerite. The pyrite occurs in groups of parallel crystals, larger than the pyrite crystals at K1. The sphalerite occurs in larger (over 1 cm) black crystals, sometimes with colorless cores. No trace of silver mineralization has been seen at K2.

At Keystone #1, the rock that is "interesting to collectors appears to fall into four general categories. The first is generally massive Rhodochrosite, faintly banded, with layers or zones along the bands of sulfides, primarily Sphalerite and Galena. This type of ore itself can be quite attractive, but is generally black on the exterior, due to oxidation of the manganese in the ore. This is the most common “ore rock,” and the majority of the mineral species are found in vugs in this ore, notably argentian Tetrahedrite, Sphalerite, Galena, Quartz, and Rhodochrosite.

"The second type of rock that only occasionally produces attractive specimens is primarily massive pyrite. The lion’s share of this material is completely solid and useless from the standpoint of most mineral collectors. At times, the pyrite is partially rotten and smells of sulfur. Occasionally, a vuggy piece can be found. The vugs are lined with lustrous Pyrite crystals. Sometimes, lovely, transparent, lustrous, greenish-yellow Sphalerite crystals are found growing upon the Pyrite.

"The third type of rock is abundant, but is rarely interesting. Nevertheless, it appears to be the primary host of an interesting form of Enargite that occurs in branching, almost dendritic groups of crystals. The rock is fine-grained and black, and hosts Quartz veins lined with druzy Quartz crystals. Very rarely, the unusual Enargite crystals can be found on the Quartz.

"The last type of productive rock is essentially a subclass of the first. Occasionally, in zones adjacent to the Rhodochrosite ore, a fine-grained, sulfide-bearing rock occurs that is primarily massive Quartz. Vugs in this rock host essentially the same assemblage of minerals as in the first rock type. Very rarely in addition, crystals of Polybasite, Proustite/Pyrargyrite, and Xanthoconite can be found in the vugs" (Meyer). This last rock type is very uncommon and many colectors who have repeatedly visited the locale have not found any of this rock that hosts the silver minerals.

Other Regions, Features and Areas containing this locality

References