Manufacture of glass in primary or semi-manufactured forms (such as sheets & plate glass) including mirror sheets and wired, coloured, tinted, toughened or laminated glass
Manufacture of electric power distribution transformers, arc-welding transformers, fluorescent ballasts, transmission and distribution voltage regulators
Manufacture of other glassware/ glass proudcts: articles of glass used in construction such as glass blocks; clock or watch glasses, optical glass and optical glass elements not optically worked; and other glass products (including glass beads) n.e.c
Operation of sand or gravel pits, basalt / porphyry, clay (ordinary), crushing and breaking of stone for use as a flux or raw material in lime or cement, manufacture or as building material, road metal or ballast and other materials for construction