The Blue River deposit outcrops on a low hill just northwest of the community of Blue River, a kilometre northwest of the Yellowhead Highway (Highway 5).
This deposit has been explored for its calcitic marble since 1983. Blue River Mines Ltd. and Ekaton Industries Inc. have carried out an extensive program of mapping, diamond drilling and bulk sampling since 1984. In 1988, 7800 tonnes of limestone were crushed by Blue River Mines. The property has been inactive since this time because limestone requests were for decorative purposes only. In a reorganization in 1989, Blue River Mines changed its name to Techmin Canada Ltd. (Fischl, 1990).
The limestone (marble) is exposed in three major outcrops over the top of the hill, the largest being 180 by 120 metres in area (Main zone), 230 metres above the valley floor of the North Thompson River. The limestone is hosted in gneiss and pegmatite of the Precambrian-Paleozoic(?) Shuswap Metamorphic Complex. Contacts with the enclosing gneiss strike 077 to 123 degrees and dip 45 to 60 degrees south. Diamond drilling indicated the limestone underlying the Main zone is at least 44 metres thick.
The Main zone is comprised mostly of coarse-grained, white, massive limestone (marble), with some pale grey patches and a few medium-grained, medium grey to blue-grey beds. Only traces of disseminated biotite, white mica and pyrite are evident. Tremolite occurs in some fracture infillings. Several medium-grained, light to medium grey, dolomitic and siliceous beds up to 3.0 metres thick were encountered during drilling. These beds tended to be more micaceous and pyritic than the enclosing limestone. Some inclusions of quartz-feldspar pegmatitic and biotitic gneiss up to 4.6 metres thick were also encountered near surface. Some results from grab sampling and diamond drilling analyzed as follows (in per cent):
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Diamond Drilling Grab Sampling
CaO 53.60 53.6
MgO 1.78 1.02
SiO2 0.23 0.71
Al2O3 0.23 0.13
Fe2O3 0.09 -
MnO 0.01 -
P2O5 0.04 -
Na2O 0.026 0.026
K2O 0.03 0.020
TiO2 0.01 -
Ig. Loss 41.6 -
Brightness 94.4 -
The drill results represent a 35.7-metre long drill hole intersection of the Main zone (Guillet, 1984). The grab sample results are an average of eight samples taken from the surface of the Main zone (Assessment Report 15725). The Main zone is estimated to contain 1.8 million tonnes of limestone based on diamond drilling (Guillet, 1984).
