The St. Lawrence Wollastonite Deposit - Overview

Canadian Wollastonite's St. Lawrence deposit occurs within a horse-shoe shaped band of quartzite open to the east. The deposit is composed of calc-silicate and silicate skarn layers interbanded and strongly folded within the enveloping quartzite. The southern boundary of the skarn is in thermal metamorphic contact with a gabbroic intrusive which has a syenitic and late pyroxenite phase. The entire package has undergone granulite facies metamorphism. Wollastonite skarn formation is limited to the inner portion of a southwest plunging fold which closes to the west. The Wollastonite skarn zones present within this inner fold cover an area of 275 acres, of which 200 are included in the St. Lawrence deposit property.

Wollastonite skarn (ca. 9.6 Mt) with an average wollastonite content of >42% but locally >80% is observed in bands averaging 12-29 meters folded repeatedly throughout the property. The average mineral content consistently associated with the wollastonite is:

	diopside/hedenbergite @ 25-40%
	feldspar (predominantly albite with relatively minor microcline) @ <10%
	quartz @ 5%
	calcite @ trace <1%
	sulfides (pyrrhotite and pyrite) <1%
	garnet, graphite,phlogopite @ trace <1%

The wollastonite skarn typically grades into a calc-silicate skarn with a wollastonite content of >20% and <35% wollastonite. The decrease in wollastonite is generally accounted for by an increase in feldspar content. Wollastonite skarns exhibit their highest grades in fold noses proximal to major north/south fault structures.

Although the mineralogy is relatively consistent throughout there exist some generalizations that can be made regarding local fluctuations of specific minerals.

	feldspar content is lowest adjacent to the intrusive contact;
	graphite only occurs at the north property boundaries and has not been identified in the southern half of the property;
	phlogopite appears to be restricted to the same area as graphite;
	calcite occasionally exceeds 1% in NE portion of property;
	hedenbergite replaces diopside at the gabbro contact