Hydro-geo-ecological safety of gold extraction from residuum by heap leaching

Mineral mining alters conditions of hydrogeology and leads to the need of reappraisal of proven reserves in the mining areas. The use of the cyanide heap leaching methods call for the exclusive validation standards of ecological safety both of the recovery and its aftereffects. For the purpose of the gold mining procedure justification in the Middle Urals, determination of groundwater flow direction velocity and rates, as well as the estimate of probability of the hydrosphere pollution, including the post-operation phase, the hydro-geo-migration modeling has been implemented. The parameters of the two-layer model are justified based on the actual data of cluster-well and single-well pumping. During open pit mining, groundwater flows undergo redistribution in the basin of a discharge. First, the drainage flow rate will reach 4 thousand cubic meter per day, and it will gradually decrease by 2 times in 10 years. In the structure of water drainage, the dominant part is taken by drawdown firstly (80%), and the percentage of the resources from the waterlogged river valley grows later on (60%). After mining completion, the flow structure changes and the direction of the pollution finger progression changes accordingly. It is shown that even in case of the worst scenarios connected with accidental leakages at the heap leaching sites, pollution concentrates under the site and never reaches the open pit mine when it is mined with water drainage. In the post-operation phase, pollution gets diluted by tens millions of times. Thus, the numerical modeling has validated the ecological safety of mining.

Rybnikova L. S., Rybnikov P. A. Hydro-geo-ecological safety of gold extraction from residuum by heap leaching. MIAB. Mining Inf. Anal. Bull. 2022;(5):25-38. [In Russ]. DOI: 10.25018/0236_1493_2022_5_0_25.

The studies were supported by the Russian Foundation for Basic Research, Grant No. 20-45-660014.

L.S. Rybnikova¹, Dr. Sci. (Geol. Mineral.), Chief Researcher, e-mail: luserib@mail.ru, ORCID ID: 0000-0002-4221-7879,
P.A. Rybnikov¹, Cand. Sci. (Geol. Mineral.), Assistant Professor, e-mail: ribnikoff@yandex.ru, ORCID ID: 0000-0002-7829-5035,
¹ Institute of Mining, Ural Branch of Russian Academy of Sciences, 620075, Ekaterinburg, Russia.

L.S. Rybnikova, e-mail: luserib@mail.ru.

1. Khokhryakov A. V., Larionova I. V., Moskvina O. A., Tseitlin E. M. A systematic approach to ensuring environmental safety in the mining industry. MIAB. Mining Inf. Anal. Bull. 2020, no. 3-1, pp. 501—517. [In Russ]. DOI: 10.25018/0236-1493-2020-31-0-501-517.

2. Kornilkov S. V., Antoninova N. Iu., Panzhin A. A., Shubina L. A., Isakov S. V. Specifying the approaches to geoinformation monitoring to assess the development dynamics of mining enterprises as natural-technological systems. Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal. 2020, no. 8, pp. 41—51. [In Russ]. DOI: 10.21440/0536-1028-2020-8-41-51.

3. Rybnikova L. S., Rybnikov P. A. Problems of self-rehabilitation of the hydrosphere and mine water purification at the post-operational stage (on the example of the Levikhinsky mine, Middle Urals). MIAB. Mining Inf. Anal. Bull. 2020, no. 3-1, pp. 488—500. [In Russ]. DOI: 10.25018/0236-1493-2020-31-0-488-500.

4. Samartsev V. N., Pozdnyakov S. P. Experience in calibration of the geofiltration model of coastal water intake by sharing data from pilot filtration works and monitoring results during operation. Inzhenernaya geologiya. 2017, no. 3, pp. 36—43. [In Russ].

5. Ivanov P., Davis P., Sizov N., Pozdniakov S. Use of groundwater level fluctuations near an operating water supply well to estimate aquifer transmissivity. Ground Water. 2021, vol. 59, no. 1, pp. 49—58. DOI: 10.1111/gwat.13018.

6. Schneider P., Wolkersdorfer C. Dimensions of water management in the extractive industries. Sustainable Industrial Water Use — Perspectives, Incentives, and Tools. 2021, pp. 73—87. DOI: 10.2166/9781789060676_0073.

7. Wolkersdorfer C., Nordstrom D. K., Beckie R., Cicerone D. S., Elliot T., Edraki M., Valente T. M., França S. C. A., Kumar P., Oyarzún Lucero R. A. and Soler A. I. G. Guidance

for the integrated use of hydrological, geochemical, and isotopic tools in mining operations. Mine Water and the Environment. 2020, vol. 39, no. 2, pp. 204—228. DOI: 10.1007/s10230020-00666-x.

8. Rybnikova L. S., Rybnikov P. A. Regularities in the evolution of groundwater quality at abandoned copper sulfide mines at the Levikha ore field, Central Urals, Russia. Geokhimiya. 2019, vol. 64, no. 3, pp. 282—299. DOI: 10.31857/S0016-7525643282-299.

9. Chiang W. H., Kinzelbach W. 3D-Groundwater Modeling with PMWIN. 1st edition. Springer-Verlag Berlin Heidelberg New York. 2001, 346 р.

10. Zheng C., Wang P. P. MT3DMS: A modular three-dimensional multispecies transport model for simulation of advection, dispersion and chemical reactions of contaminants in groundwater systems. Documentation and User's Guide. Report No.: SERDP-99-1. U.S. Army Engineer Research and Development Center, Vicksburg, MS, 1999.

11. Winston R. B. ModelMuse Version 4: a graphical user interface for MODFLOW 6. Scientific Investigations Report 2019-5036. 2019, 10 p. DOI: 10.3133/sir20195036.

12. White J. T., Foster L., Fienen M. N., Winterle J. R. Toward reproducible environmental modeling for decision support: A worked example. Frontiers in Earth Science, Hydrosphere. 2020. DOI: 10.3389/feart.2020.00050.

13. Yazvin L. S. Estimation of forecast resources of drinking groundwater and provision of the population of Russia with groundwater for domestic drinking water supply. Prospect and protection of mineral resources. 2003, no. 10. [In Russ].

14. Rekomendatsii po gidrogeologicheskim raschetam dlya opredeleniya granits 2 i 3 poyasov zon sanitarnoy okhrany podzemnykh istochnikov khozyaystvenno-pit'evogo vodosnabzheniya [Recommendations on hydrogeological calculations for determining the boundaries of zones 2 and 3 of sanitary protection zones of underground sources of household and drinking water supply], Moscow, VNII «VODGEO», 1983, 103 p.