Silica of commercial interest occurs throughout the whole of Canada as vein and intrusive masses and as sand, sandstone and quartzite deposits; and silica mining operations are conducted in all provinces except Prince Edward Island. Silica is recovered in lump form for use as metallurgical flux and in the manufacture of silicon and ferrosilicon alloys; as sand for glass and glass fibre manufacture, for use in foundry moulding, and for the production of silicate chemicals, silicon chips and optical fibres; and as finely ground silica flour for ceramic, asbestos cement and concrete products. Although Canada is selfsufficient with regard to most of its requirements for silica, significant tonnages of highquality sand for glass and foundry applications continue to be imported, chiefly by Ontario. CANMET and its predecessor, Mines Branch, have continued to promote interest in domestic silica resources over the years by laboratory research and development studies. These studies have primarily been in the area of beneficiation of submitted samples by a wide variety of mineral processing techniques, and the evaluation of the resulting products for suitability as glass and foundry sand, and for other purposes. This report summarizes no fewer than 115 studies of silica samples undertaken during the period 1923 to 1986. Reference is also made to R&D by other organizations including provincial governments and private sector research laboratories.