Dolomite

The Monarch (082N 019) and Kicking Horse deposits occur in the steep cliffs on either side of the Kicking Horse River, about 4 kilometres northeast of Field, in Yoho National Park. The Kicking Horse deposit is at the 1524-metre elevation on Mount Field on the north side of the river, and the East and West Monarch deposits are at the 1560 and 1621-metre elevations respectively, on Mount Stephen, on the south side of the river. The Monarch deposit was located in 1884 during construction of the Canadian Pacific Railway. The East Monarch ore zone was the first to be recognized, and the West Monarch zone, known originally as the Couverapee, was not discovered until about 1916. The original Couverapee property was owned by W.D. Adkins who shipped 20 tonnes in 1916. The workings consisted of one large pillared stope with some crosscutting and drifting. In 1919 there was litigation regarding boundaries between the owners of the Couverapee and (East) Monarch properties. A survey proved that the Couverapee was within the Monarch holdings and the two properties were amalgamated under the management of Mr. Adkins. The Couverapee and the original Monarch mine became known as the West and East Monarch, respectively. The Kicking Horse showings, known originally as the Black Prince, were mentioned briefly in old reports but received little attention until 1925.

The region is within the fold-and-thrust belt of the Cordillera. Although the structural style varies within the area, northeast- directed thrust faults and associated folds and overturned folds with northwest axes dominate. The Monarch-Kicking Horse deposits occur in a thick succession of massive to thin-bedded limestone and dolomite of the Middle Cambrian Cathedral Formation. Characteristically, the deposits are in close proximity to carbonate bank margins. The Monarch-Kicking Horse deposits are in platformal carbonates just east of a transition to basinal shale and limestone of the Middle Cambrian Chancellor Group (Fieldwork 1980, page 105).

The Monarch and Kicking Horse deposits lie on the east limb of a gentle anticline, the axis of which strikes about 335 degrees and plunges northward at a small angle. The deposits comprise a number of separate and discrete mineralized zones within massive to brecciated dolomite that forms a 60-metre stratigraphic interval in the lower 125 metres of the Cathedral Formation. The dolomite zone cuts sharply into underlying well-bedded limestone and dolomite and is overlain by well-bedded carbonate rock. The brecciated dolomite that hosts the orebodies consists either of a stockwork of white dolomite veins in grey dolomite or of light grey dolomite fragments in dark grey dolomite. Dolomite alteration zones immediately underlying the orebodies have original bedding preserved. The dolomite zones and orebodies trend northerly, parallel to both late normal faults, and to the abrupt carbonate platform-basinal shale transition zone.

The orebodies occur as narrow elongate runs in brecciated dolomite. They die out gradually along trend into barren, unmineralized dolomite but have sharp lateral boundaries. Sulphides, consisting of amber-coloured sphalerite, galena, minor pyrite and trace chalcopyrite, are disseminated in the dolomite matrix of breccias and form irregular veinlets cutting both matrix and fragments. Coarse sphalerite and galena commonly rim dark dolomite fragments; spar dolomite is interstitial.

Dolomitization and the development of breccia and associated cavities cannot be directly related to any late fault structures. Faults cutting the deposits are not conspicuous and one of the two supposed boundary faults, the Stephen-Dennis fault, is dominantly a stratigraphic, not a structural break. The location of the Monarch-Kicking Horse deposits in dolomitized breccia adjacent to a platformal bank margin suggests rather a regional stratigraphic control of mineralization (Fieldwork 1980, page 106).

The West Monarch orebody was 536 metres long, 48 metres wide and 2.4 to 16.7 metres thick, averaging 5.7 metres. The orebody rises at an angle of 8 degrees in a direction of 165 degrees.

The original East Monarch orebody lies about 198 metres east of the West Monarch orebody and is parallel to it. As first mined, it consisted of two closely-spaced orebodies but later development indicated a number of orebodies occurring in an en echelon manner over an explored length of 701 metres.

The Kicking Horse orebodies appear to line up with those of the Monarch across a gap of 1158 metres between the cliff faces of Mount Stephen and Mount Field. Because of this fact and because they occur in essentially the same structural position, it is probable that they are parts of a major ore zone that has been eroded by the Kicking Horse Valley (Minister of Mines Annual Report 1949, page A208). The No. 1 Kicking Horse orebody or zone was 176 metres long in a direction of 330 degrees and is flat. In its southern part it averaged 12.1 metres wide and 4.5 metres thick. The No. 2 or Western zone was 426 metres long, trending 320 degrees for 213 metres then changing direction to 303 degrees; it is irregular in outline.

Grade is variable in all the orebodies. Lead is more localized than zinc, and the end limits of the orebodies tend to be more zinc-rich than the average. The Monarch mine orebodies contained a higher percentage of lead than the Kicking Horse mine.

Production from the East Monarch deposit began in 1888 and continued intermittently until 1925, and amounted to about 42,545 tonnes. Development work continued through 1926 and most of 1927. The mine began producing again in 1929, with only one year, 1932, in which all work was suspended. There was no production in 1931 and 1932. By the end of 1935 ore reserves had been largely depleted, and the mill was closed. Development work was done during the following four years (1936 to 1939), and milling operations were resumed in 1940. The intermittent production from 1929 to 1940 was from the West Monarch deposit and amounted to about 318,024 tonnes. In 1941, ore from the Kicking Horse deposit was trucked to the mill for the first time, since which time this mine has produced most of the tonnage for the period 1941 to 1952 (about 466,440 tonnes). Note that the production statistics for the Kicking Horse mine are included with that of the Monarch mine (082N 019). Mining and milling ceased at the Monarch and Kicking Horse mines in August 1952, when the Monarch orebody was exhausted. Remaining reserves at the Kicking Horse deposit are 27,213 tonnes grading 8 per cent zinc (Minister of Mines Annual Report 1952, page A205). Development and exploration work ceased at the Kicking Horse mine in November of the same year. Metal prices were not favourable for continued exploration, and these properties remained idle during 1953. In September, 1954, they were abandoned, and all salvable material was removed from underground. In 1957, the mill equipment was removed and shipped to the property of Cowichan Copper Co. Ltd. on Cowichan Lake. While removing the equipment, lead and zinc concentrates were recovered and shipped to the Trail smelter.