Pyrite Sphalerite

Specimen Summary

Lucky Jim Mine

Zincton, British Columbia

Massive black sphalerite crystals with disseminated pyrite.

Sphalerite is the main ore mineral for zinc, and although relatively common, finding it in commercial amounts is somewhat rarer. The zinc will give the mineral a yellow or red hue, but iron can replace the zinc in the atomic structure, making the crystals black. Rarely, cobalt finds its way into the structure, and produces green crystals.

Pyrite is a common iron sulphide mineral found in many different geological settings. It has a brassy-yellow metallic colour that has caused many people to mistake it for gold, giving it its other name, “Fool’s gold”. Pyrite and gold can be quite easily distinguished from one another: pyrite is less yellow and much lighter and harder than gold, which can be scratched with a pocket knife.  Pyrite often forms perfect cubes, which can grow to quite large sizes, because of its crystal structure. The word pyrite comes from the Greek word ‘pyr’ meaning fire, because it will spark if hit with other metal or stone objects.

Although sphalerite is a relatively soft mineral, it can be cut (faceted) into attractive gems that are used for mineral displays.

This particular specimen comes from the Lucky Jim mine in Zincton in West Kootenay region of southeastern BC. Today, Zincton is one of BC’s many ghost towns, slowly crumbling and rusting, overgrown by the surrounding forest. In its heyday, around 200 people lived there, working the rich Lucky Jim zinc claims in the surrounding area.

Zincton was founded in 1892 and at one point was the largest producer of zinc in the Slocan area. It was even served by the Kaslo and Slocan Railway line, which transported ore to the Pilot Bay smelter to the south. The town was destroyed by a fire in 1910 but was rebuilt in 1927 by the Victoria Syndicate, who had acquired several of the surrounding zinc claims.

In the late 1800s, many prospectors came to the Slocan area in search of silver. Many were disappointed to find zinc, even in such abundance as found on the Lucky Jim claims. However, the turn of the century brought new industrial processes and the demand for zinc soared.

The ore at the Lucky Jim mine is mainly sphalerite and pyrite with gangue (waste) minerals calcite and minor amounts of quartz. The ore occurs as pods or thin veins in limestone host rock. Several main ore zones were mined, each contained within fractured zones of rock that allowed the ore-bearing fluids to move through the host rock and ultimately form the deposits. 

Production from the Lucky Jim mine at Zincton began with the first shipment of ore in 1893 and continued intermittently until 1959, when ore reserves were depleted. The total recorded production amounts to 1,065,798 tonnes with 18,634,368 grams silver, 2799 grams gold, 194,847 kilograms cadmium, 3,697,184 kilograms lead and 79,798,689 kilograms zinc.

Specimen Data

 

The information listed below relates to the current holding location or collection that the sample is from, and whether the item is viewable at that location or is part of a private collection. Coordinates are given as guides, and we remind you that collecting specimens from these locations is not allowed. Caution is advised visiting such sites and Below BC assumes no responsibility for any injuries or trespassing charges that may occur as a result of the viewer entering these sites.

Collection Details

Original Collection:

Pacific Museum of Earth (PME)

Sub Collection:

Sutton-Thompson

Collection ID:

PME-387

Virtual Museum ID:

17-PME387

Accessibility:

Date Added to VM:

2017-11-02

Location Information

Sample Origin:

Zincton, B.C.

Specific Site:

Lucky Jim Mine

UTM Easting:

485419

UTM Northing:

5542820

Datum:

11 (NAD83)

Coordinate Accuracy:

Approximate

Specimen Details

VM Category:

Mineral

Primary Features:

Pyrite Sphalerite

Primary Mineral Formula:

FeS2 · (Zn,Fe)S

Primary Category:

sulphide

Secondary Features:

Advanced Geological Information

 

The following section provides geological data relating to the specimen or the site it was collected from, when available. Information has been obtained from various sources including private and government datasets but may not be up to date. Any geological time periods or ages listed often relate to the primary geology of the area, and may not be the actual date of an event such as mineral formation.

Geological Formation:

Slocan Group

Geological Period:

Triassic

Stratigraphic Age:

201.3 to 252.17 Million Years

Geological Belt:

Omineca

Geological Terrane:

Quesnellia

Minfile ID:

082KSW023

Minfile Link:

http://minfile.gov.bc.ca/Summary.aspx?minfilno=082KSW023

Site Details:

The former Lucky Jim mine is located immediately southwest of Bear Lake and the historic mining community of Zincton.

The area is underlain by northwest striking and southwestward dipping Triassic Slocan Group sedimentary and metasedimentary rocks. The fissile lower portion of this group was historically referred to as the "slate belt" but includes limestone, calcareous argillites and quartzite beds. In the vicinity of the former Lucky Jim mine this unit is referred to as the Zincton member of the Slocan Group. Several relatively thin granitic sills and dikes intrude this strata.

The Lucky Jim mine is within a package of thinly bedded, slaty, calcareous argillite and quartzite as well as several distinct bands of limestone. The sediments strike 320 degrees and dip 40 to 80 degrees southwest. The hostrock limestone, within the former Lucky Jim mine area, is part of a major west-northwest plunging crossfractured fold structure. Brecciation, especially evident in the limestone, suggests that considerable differential movement has occurred.

Where undeformed, the "Lucky Jim" limestone has an average thickness of approximately 9 metres and a horizontal width of 6 to 61 metres. It has a faintly banded to massive appearance, a finely crystalline texture, and dark grey to black colour. Where strongly deformed, as it is throughout the productive section of the mine, it has been significantly thickened by folding. As a result, most of the limestone has been brecciated and, locally fractured.

The general structure controlling the Lucky Jim mineralization is the west-northwest plunging fold complex which can be traced from the highest to lowest levels of the mine. On successive cross- sections, the "mine fold" varies considerably in size and outline. Within the upper, southeasterly parts of the mine, it is essentially an irregular dragfolded, buckled and thickened interval of the limestone bed with a general southwesterly dip of approximately 40 degrees. Within the lower, northwesterly workings, it is a wide, complexly folded, pinching and swelling mass of limestone relating to a broad, flat wrap in the generally southwesterly dipping section. The resulting deformation has produced a characteristic breccia structure, with thicknesses ranging from 15 to 45 metres or more.

The most apparent structural controls of the ore mineralization are: (a) vertical crossfractures, or crossfracture zones striking at approximately 090 degrees (right angles) to the average regional strike of the bedding and are themselves mineralized to varying degrees; (b) plunging fold or buckle axes, with the replacement mineralization occurring as streaks, masses and disseminations within the limestone (breccia); (c) vertical longitudinal fractures, or zones of fracturing roughly parallel to the general strike of the limestone within the lower mine workings and (d) combinations of the above noted controls. Pervasive replacements on zones or crossfractures are produced near vertical tabular orebodies with widths of up to 12 metres, and lengths related to the local widths of limestone traversed by the crossfractures. Vertical longitudinal fractures are apparently less important as ore controls than (a) and (b). These probably account for the bulk of the mineralization below the No. 5 level.

The orebodies at the Lucky Jim mine are the result chiefly of replacement of limestone. Mineralization predominantly consists of sphalerite, pyrite, calcite and very minor quartz in a limestone (calcite) gangue. The relative proportion of pyrite and sphalerite varies considerably, and some mineralization is composed dominantly of pyrite. The ore in any body occurs as pods, lenses, stringers and irregular masses, locally forming a systematic pattern but more often not. The boundaries of an orebody are commonly distinct, with very little gradation from ore through low-grade material, into barren rock. Small, isolated patches of mineralization are rare. Galena is common in the crossfracture zones of the upper levels (above No. 5 level), but has not been a recoverable constituent of the ore below the No. 5 level. Tin occurs as minute amounts within the sphalerite and partly in the form of cassiterite. Other minerals include pyrrhotite and, locally, very minor arsenopyrite.

Three important fracture zones have been explored and developed at the former Lucky Jim mine, each hosting significant orebodies. From northwest to southeast these are the Glory Hole fracture zone, the Central or Main fracture zone and the Big or New fracture zone. The zones are 38 to 53 metres wide and 84 to 91 metres apart. In the Glory Hole and Central or Main fractures, ore was hosted in irregular, chimney-shaped ore shoots, up to 15 metres diameter, in limestone on either side of the fissure or within narrow zones of closely-spaced fractures or fissures. Four important and distinct fracture zones were discovered and mined in the Central or Main zone, which was 46 metres wide. In the Big fracture zone, mineralization was hosted in replacement bodies developed along strike of the limestone. The largest mineralized zone of this mine, the Larson stope, extends from 61 metres above the No. 3 level to the No. 4 level, maintaining an average width of 3 metres over 46 metres length. The zone contained considerable high grade lead ore.

The Lucky Jim mine is developed by six adits at elevations ranging from 1083 metres at the portal of the No. 9 level (haulage level) to 1420 metres at the No. 1 level. The orebodies have been mined through a vertical range of approximately 365 metres. Most of the development work has been, and most of the production has come from above No. 5 level at the 1220 metre elevation. Early operations were confined to the Glory Hole and Central fracture zones while after 1926 most was from the Big fracture zone. Production from the Lucky Jim mine began with the first shipment of ore in 1893 and continued intermittently until 1959. Total recorded production amounts to 1,065,798 tonnes with 18,634,368 grams silver, 2799 grams gold, 194,847 kilograms cadmium, 3,697,184 kilograms lead and 79,798,689 kilograms zinc recovered.

Interest in the former Lucky Jim mine since 1959 has been expressed by exploration by Swim Lake Mines Ltd. in 1971, J. Bell in 1983 and J. Ross in 1987. No further underground development or production was done. A rock sample taken near the upper adit on the St. George claim in 1983, under option to Nomad Energy and Resources Ltd., yielded 32.8 per cent zinc, 66.17 grams per tonne silver, 0.49 per cent lead and 0.18 per cent cadmium (Assessment Report 12249). The sample, ZR-003, was a 50-centimetre chip sample across a fracture zone in limestone containing sphalerite, pyrite and galena in a gangue of calcite and ankerite.

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