| 27. | Administrative, operations and project expenses |
| | | 2017 | | 2016 | | 2015 | | |||
| Administrative expenses | | | | | | | | | | |
| General expenses | | | 723,341 | | | 556,563 | | | 393,971 | |
| Labor expenses | | | 624,424 | | | 657,051 | | | 491,748 | |
| Taxes (1) | | | 362,963 | | | 663,889 | | | 730,841 | |
| Depreciation and amortization | | | 53,796 | | | 45,765 | | | 84,425 | |
| | | | 1,764,524 | | | 1,923,268 | | | 1,700,985 | |
| Operations and project expenses | | | | | | | | | | |
| Exploration costs | | | 1,341,940 | | | 728,590 | | | 1,584,249 | |
| Commissions, fees, freights and services | | | 471,657 | | | 568,513 | | | 878,259 | |
| Taxes | | | 324,223 | | | 286,331 | | | 348,871 | |
| Labor expenses | | | 310,947 | | | 278,383 | | | 309,021 | |
| Maintenance | | | 122,273 | | | 147,197 | | | 181,630 | |
| Depreciation and amortization | | | 95,516 | | | 177,252 | | | 86,215 | |
| Fee for regulatory entities | | | 63,470 | | | 87,325 | | | 77,909 | |
| Corporate projects | | | 29,702 | | | 301,854 | | | 456,159 | |
| Others | | | 166,337 | | | 176,242 | | | 111,955 | |
| | | | 2,926,065 | | | 2,751,687 | | | 4,034,268 | |
| (1) | Mainly corresponds to the recognition of the wealth tax. See Note 10 - Taxes. |