Various masses of dolomite and limestone occur over a 3 kilometre length in a northwest trending pendant of Upper Triassic Karmutsen Formation(?) metavolcanics and metasediments (Geological Survey of Canada Open File 611) just northwest of Carlson Lake, 13 kilometres east of Pender Harbour on the Sechelt Peninsula. This pendant lies in diorite and quartz diorite of the Jurassic to Tertiary Coast Plutonic Complex. The beds within the pendant strike north and dip moderately to steeply east. The beds are comprised mostly of carbonate outcropping over widths in excess of 150 metres with some amphibolite, skarn altered metavolcanics and north trending, steeply dipping andesitic to basaltic dykes(?) 2 to 20 metres wide. These units are displaced by faults commonly trending 160 to 165 degrees.
The carbonates consist of fine to coarse-grained, white to medium grey, banded limestone and fine to medium-grained, white to medium grey, massive to mottled dolomite. Minor to trace amounts of quartz, muscovite, serpentinite, diopside, olivine, talc, graphite and pyrite are present in the limestone. The dolomite contains minor chlorite and quartz. Veins of dolomite and calcite commonly cut the dolomite. Ten composite samples collected from various limestone outcrops averaged 55.3 per cent CaO, 0.5 per cent MgO, 0.7 per cent SiO2, 0.2 per cent R2O3 and 43.3 per cent ignition loss (Wright Engineering, 1983, page 7 in Prospectus by Candol Developments Ltd.). Assays of the dolomite range from 16.8 to 20.0 per cent MgO (Assessment Report 15593, page 11).
Reserves were initially estimated by Wright Engineering in 1983 for limestone and dolomite over a 3 kilometre strike length. Indicated reserves estimated to a depth of 50 metres and inferred reserves estimated from 50 to 300 metres are given as follows (Wright Engineering, 1983, page 4):
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Indicated Inferred Total
(tonnes) (tonnes) (tonnes)
Dolomite 17,500,000 100,000,000 117,500,000
Limestone 7,500,000 20,000,000 27,500,000
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Drilling between 1985 and 1987 defined a 30 to 80 metre wide body of dolomite at least 500 metres long, that is bounded to the west by limestone and to the east by an andesitic dyke. The deposit is estimated to contain measured geological reserves of 3.5 million tonnes of dolomite averaging 19.2 per cent MgO for an average width of 55 metres over a 500 metre strike length down to 50 metres in depth (Assessment Report 15593, page 23; Open File 1992-1).
Peninsula Lime and Magnesia Ltd. carried out some initial stripping and mapping between 1970 and 1971. A small crushing mill was assembled by the company during this time. A minor amount of work was conducted by Stoney Plain Industries in 1978. Candol Developments Ltd. carried out an extensive program of mapping, sampling and diamond drilling (1423 metres) between 1983 and 1987.
