| Naics index | Naics index description |
|---|---|
| 212230 | Nickel concentrates recovery |
| 212230 | Nickel ore beneficiating plants |
| 212230 | Nickel ore mine site development for own account |
| 212230 | Nickel ores mining and/or beneficiating |
| 212230 | Smithsonite mining and/or beneficiating |
| 212230 | Sphalerite mining and/or beneficiating |
| 212230 | Willemite mining and/or beneficiating |
| 212230 | Zinc ore mine site development for own account |
| 212230 | Zinc ores mining and/or beneficiating |
| 212230 | Zinc-blende (sphalerite) mining and/or beneficiating |