Wow! Only ten uses, five of which are for naming the Iron Hills!

• 5.055 Gnaws iron, bites steel;
• 8.017 they fastened one of the large iron hooks
• 12.074 with iron scales
• 15.021 in the Iron Hills,
• 15.043 and he began reckoning the distance to the Iron Hills
• 16.004 hurrying from the Iron Hills,
• 16.029 and the dwarves of the Iron Hills?’
• 17.031 Their caps were of iron
• 17.031 and they were shod with iron,
• 17.051 the dwarves of the Iron Hills plunged in,