| | | 21112 | Crude Petroleum
Extraction | 5 | | Crude Petroleum
Extraction 21112 | Oil and Gas Extraction 2111 | Oil and Gas Extraction 211 | Mining, Quarrying, and
Oil and Gas Extraction 21 |
| | | 21113 | Natural Gas Extraction | 5 | | Natural Gas Extraction 21113 | Oil and Gas Extraction 2111 | Oil and Gas Extraction 211 | Mining, Quarrying, and
Oil and Gas Extraction 21 |
| | | 212 | Mining (except Oil and
Gas) | 3 | | | | Mining (except Oil and
Gas) 212 | Mining, Quarrying, and
Oil and Gas Extraction 21 |
| | | 2121 | Coal Mining | 4 | | | Coal Mining 2121 | Mining (except Oil and
Gas) 212 | Mining, Quarrying, and
Oil and Gas Extraction 21 |
| | | 21211 | Coal Mining | 5 | | Coal Mining 21211 | Coal Mining 2121 | Mining (except Oil and
Gas) 212 | Mining, Quarrying, and
Oil and Gas Extraction 21 |
| | | 2122 | Metal Ore Mining | 4 | | | Metal Ore Mining 2122 | Mining (except Oil and
Gas) 212 | Mining, Quarrying, and
Oil and Gas Extraction 21 |
| | | 21221 | Iron Ore Mining | 5 | | Iron Ore Mining 21221 | Metal Ore Mining 2122 | Mining (except Oil and
Gas) 212 | Mining, Quarrying, and
Oil and Gas Extraction 21 |
| | | 21222 | Gold Ore and Silver Ore
Mining | 5 | | Gold Ore and Silver Ore
Mining 21222 | Metal Ore Mining 2122 | Mining (except Oil and
Gas) 212 | Mining, Quarrying, and
Oil and Gas Extraction 21 |
| | | 21223 | Copper, Nickel, Lead, and
Zinc Mining | 5 | | Copper, Nickel, Lead, and
Zinc Mining 21223 | Metal Ore Mining 2122 | Mining (except Oil and
Gas) 212 | Mining, Quarrying, and
Oil and Gas Extraction 21 |
| | | 21229 | Other Metal Ore Mining | 5 | | Other Metal Ore Mining 21229 | Metal Ore Mining 2122 | Mining (except Oil and
Gas) 212 | Mining, Quarrying, and
Oil and Gas Extraction 21 |