Ammosov North-Eastern Federal University, Yakutsk, Russia:

V. S. Markov, Associate Professor, Candidate of Engineering Sciences, marko-valeri@mail.ru
A. A. Nikolaeva, Head of Laboratory
L. V. Petrova, Senior Lecturer

Chinakal Institute of Mining, Siberian Branch, Russian Academy of Science, Novosibirsk, Russia:
V. N. Labutin, Senior Researcher, Candidate of Engineering Sciences

A critical analysis of the technical and economic indicators of systems and equipment used in underground mining of placers in the north-east of Russia suggests that the existing technologies have practically exhausted their capabilities. It is required to science-based evaluate and introduce blast-free mining technologies on the ground of studies and application of high-performance mining machines and mechanisms improving efficiency and safety of mining operations. The article describes the experimental results obtained in a placer mine in Yakutia in the course of permafrost drivage by roadheader GPKS equipped with a cutting head with a 55 kW capacity drive and with a percussion body having an impact energy of 1.7 kJ. The rate of penetration is about 1 m/h, the working speed is 3–4 m per shift at the operation factor of 0.5, which is almost three times higher than the drivage using drillingand-blasting. For the development of Solur diamond fi eld and the similar placer deposits, it is offered to apply room-andpillar method with backfilling and using roadheaders and self-propelled equipment. The research has allowed evaluation of the basic conceptual principles of underground placer mining in the permafrost zone.

1. About the state and use of mineral resources of the Russian Federation in 2012 : State Report. Moscow : Ministry of Natural Resources and Ecology of the Russian Federation, 2014. (in Russian)
2. Vorontsova N. Main gold-mining regions of the Far-Eastern Federal District decreased the gold extraction in 2013. Dalnevostochnyy kapital. 2014. p. 2.
3. Dyakonov V. A., Gurov S. D., Ilkovskiy K. K., Malikov E. F., Naumov G. G., Sherstov V. A. State and ways of increasing of tin extraction efficiency in the Sakha Republic (Yakutia). Yakutsk : Yakutsk Scientific Center of the Siberian Branch of the Russian Academy of Sciences, 2000. 100 p.
4. Salmanov P. H., Danzanov V. B. Improvement of underground mining technology with application of mobile equipment. Kolyma. 1980. No. 5. pp. 4–6.
5. Egorov I. K., Tarasov N. I. Destruction of permafrost rocks by heading machines. Tsvetnaya metallurgiya. 1985. No. 1. pp. 28–32.
6. Ivanov V. G., Lyashenko V. P., Gorbunov S. P. et al. Experience of application of cutter-loaders on underground mining of placers. Kolyma. 1985. No. 7. pp. 7–8.
7. Lyashchenko V. D., Ivanov V. G., Danzanov V. B. Experience of application of continuous heading machines during the excavations in “Severovostokzoloto” enterprises' mines. Kolyma. 1983. No. 10. pp. 8–10.
8. Dietze A., Mischo H. Possibilities and Restrictions for the New Generation of Mining Machines Using Mechanical Excavation Methods in Complex Drift Driving Systems in Underground Hard-Rock Mining. Mine Planning and Equipment Selection : Proceedings of the 22^nd MPES Conference, Dresden, Germany, 14th – 19th October 2013. pp. 291–301.
9. Salsani A., Daneshian J., Shariati Sh, Yazdani-Chamzini A., Taheri M. Predicting roadheader performance by using artificial neural network. Neural Comput & Applic. 2014. Vol. 24. pp. 1823–1831.
10. Abdolreza Y.-C., Yakhchali S. A new model to predict roadheader performance using rock mass properties. Journal of Coal Science & Engineering (China). 2013. Vol. 19, No.1. pp. 51–56.
11. Ebrahimabadi A., Goshtasbi K., Shahriar K., Cheraghi Seifabad M. Predictive models for roadheaders' cutting performance in coal measure rocks. Bulletin of the Earth Sciences Application and Research Centre of Hacettepe University, Yerbilimleri. 2011. Vol. 32(2). pp. 89–104.
12. Selective heading machine Alrine Westfalia. Gornaya promyshlennost. 1995. No. 1. pp. 40-41. (in Russian)
13. V. S. Markov, V. A. Sherstov, V. K. Elshin, S. T. Sofronov. Method of definition of permafrost macrofragmental rocks strength coefficient. Patent RF, No. 2188944. Applied: 19.09.2000. Published: 10.09.2002.
14. Labutin V. N., Markov V. S. Prospects of application of combined method of rocks destruction. Gornyy informatsionno-analiticheskiy byulleten. 2015. No. 12. pp. 325–333.
15. Markov V. S., Labutin V. N., Nikolaeva A. A. Chamber systems in underground mining diamond placers «Solur». Gornyy informatsionno-analiticheskiy byulleten. 2014. No. 9. pp. 365–370.
16. Laubscher D., Jacubec J. The MRMR Rock Mass Classification for jointed rock masses. Foundations for Design. Brisbane, 2000. pp. 475–481.