OTHER MINING AND QUARRYING (251, 252 AND 253) STONE QUARRYING, CLAY AND SANDPITS : 251 : Dimension stone (granite, marble, slate, and wonderstone) 2511: 25110: Limestone and limeworks : 2512: ... Mines engaged in the extraction of iron ore, titaniferous iron ore, magnetite and iron sand, and in beneficiating and otherwise preparing such …Web