Russian Academy of Natural Sciences, Moscow, Russia:

V. Zh. Arens, Honorary Vice-President of the Russian Academy of Natural Sciences, Professor, Doctor
of Engineering Sciences
A. S. Khrulev, Doctor of Engineering Sciences
G. Kh. Khcheyan, Chief Academic Secretary of Mining and Metallurgical Section, mogmsraen@mail.ru

GEOTEP Research and Production, Moscow, Russia:

M. I. Fazlullin, Chief Executive Officer, Doctor of Engineering Sciences

The authors discuss prospects, advantages and process flows of the hydraulic borehole mining method (HBM) in terms of the buried thin and thick gold placers in permafrost. Geology, equipment and vehicles are described. The data of experimental and semi-commercial extraction of gold from a buried coastal placer at the Ryveem River in the area of the former Polyarninsky Mining and Processing Plant (Chukotka) are analyzed. The applied HBMM included jetting of productive stratum in an unflooded chamber, haulage of broken material to a borehole and hydraulic lift of gold-bearing sand to the surface. Treatment of gold-bearing sand used a deep filling gateway. The application of HBMM in thick permafrost placers involves thawing of frozen sediments by warm water and air lift of thawed sands. The engineering solutions proposed in the article are recommended for mining a gold placer to 30 m thick in the area of the Bolotny Stream (Magadan Region). According to calculations, the technology enables production to 1 t of gold annually. In case of outlying and inaccessive placers, it is proposed to extract fine gold using the HBMM-formed voids as chambers for gold extraction from sluice tailings after HBMM by in-situ leaching and from old waste of earlier gold mining by classical (dry digging) technology.

1. Adams M. D. Gold Ore Processing: Project Development and Operations. 2^nd ed. Amsterdam : Elsevier, 2016. 980 p.
2. Liu Y., Wei J., Ren T., Lu Z. Experimental study of flow field structure of interrupted pulsed water jet and breakage of hard rock. International Journal of Rock Mechanics and Mining Sciences. 2015. Vol. 78. pp. 253–261.
3. Arens V. Zh., Babichev N. I., Bashkatov A. D., Gridin O. M., Khrulev A. S., Khcheyan G. Kh. Hydraulic Borehole Mineral Mining. 2^nd ed. Moscow : Gornaya kniga, 2011. 295 p.
4. Drobadenko V. P., Malukhin N. G., Vilmis A. L. Problems and prospects of hydraulic borehole mining of minerals. Zolotodobycha. 2011. No. 155. pp. 17–19.
5. Aksyutin O. E., Kazaryan V. A., Ishkov A. G., Khloptsov V. G., Teplov M. K. et al. Construction and exploitation of reservoirs in permafrost sedimentary rocks. Izhevsk : Institut kompyuternykh issledovaniy, 2013. 432 p.
6. Nitsevich O. A., Tsurlo E. N., Yanushenko A. P. The experience of volume and form definition of excavated breast during down hole hydro-extraction. Gornyi Zhurnal. 2011. No. 2. pp. 32–34.
7. Bagazeev V. K., Valiev N. G., Simisinov D. I. Physico-mechanical substantiation of rock mass jetting in hydraulic borehole mining of placers. Gornyi Zhurnal. 2015. No. 12. pp. 25–27. DOI: 10.17580/gzh.2015.12.05
8. Britan I. V. The state of hydraulic mining by boreholes. The crisis of the idea or short-sightedness? Nedropolzovanie-XXI vek. 2013. No. 6. pp. 46–51.
9. Rochev V. F. Applicability of hydraulic mining at gold placers in Southern Yakutia. Gornyi Zhurnal. 2016. No. 9. pp. 50–52. DOI: 10.17580/gzh.2016.09.10
10. Surin S. D., Savich O. I. Technological advancement in construction and operation of underground chambers in permafrost rocks. Proceedings of V Conference of Russian Geocryologists. Moscow : Universitetskaya kniga, 2016. Vol. 1. pp. 151–157.

11. Bondarev E. A., Rozhin I. I., Popov V. V., Argunova K. K. Assessment of possibility of natural gas hydrates underground storage in permafrost regions. Earth’s Cryosphere. 2015. Vol. 19, No. 4. pp. 58–67.
12. Bondarchuk I. B., Shenderova I. V. Classification of hydraulic borehole mining technological processes during pay zone development. IOP Conference Series: Earth and Environmental Science. 2015. Vol. 24. DOI: 10.1088/1755–1315/24/1/012004
13. Positive Preliminary Evaluation of Borehole Mining at the Hansen Uranium Deposit. 2012. Available at: https://www.asx.com.au/asxpdf/20120213/pdf/4249l4sksggk96.pdf (accessed: 19.04.2018).
14. Technical Parameters of Jet Mining. Kinley Exploration. Available at: http://www.hydraulicboreholemining.com/technical-parameters-of-jet-mining (accessed: 19.04.2018).
15. Jet Boring/Borehole Mining. RCS Group of Companies, 2018. Available at: http://rcsenergy.ca/jetboring-borehole-mining (accessed: 19.04.2018).
16. Rukovich A. V., Rochev V. F. Using the method of hydraulic borehole mining for placer gold deposits in Southern Yakutia. Advances in Current Natural Sciences. 2017. No. 10. pp. 101–106.