Paragraph 6
Use for any of the following processes so far as not included in paragraph 5 and except a process ancillary to the getting, dressing or treatment of minerals, carried on in or adjacent to a quarry or mine:—
(a)
burning of building bricks;
(b)
lime or dolomite burning;
(c)
production of calcium carbide;
(d)
foaming, crushing or screening of stone or slag.