Institute of Mining, Far East Branch, Russian Academy of Sciences, Khabarovsk, Russia:

M. A. Gurman, Senior Researcher, Candidate of Engineering Sciences, mgurman@yandex.ru
L. I. Shcherbak, Senior Engineer-Mineralogist

Saint-Petersburg Mining University, Saint-Petersburg, Russia:

T. N. Aleksandrova, Head of a Chair, Doctor of Engineering Sciences

The article presents the research findings on applicability of flotation methods in processing of lowgrade gold- and carbon-bearing ore of Durminskoe deposit. Percentage of sulfi des in the studied ore is 5–6%, and the basic sulfide mineral is pyrite. The gold content is 2.8 g/t. According to the analyses, the majority of gold (65%) is present in fine aggregates with quartz and sulfi des, and as fine dissemination in sulfide minerals. Gold particles are mostly under 0.05 mm in size. It is found that the ore contains free carbon adjacent to quartz metasomatites, disseminated or concentrated as strings and nests. The size of carbon-bearing inclusions is 0.01–0.05 mm. The carbon content of the ore: С_total – 0.78%, С_org – 0.56%. It has experimentally been found that the ore shows moderate sorption activity toward the gold-andcyanide system. The presence of gold-bearing sulfides, readily floatable particles of fine metallic gold and carbon particles possessing natural floatability predetermined the ore processing by flotation. The efficiency of sequential flotation of carbon- and gold-bearing particles in order to extract the most rebellious part of the ore in the concentrate is proved experimentally. As against the bulk flotation, the sequential process flow ensures higher gold recovery in the concentrate by 1.97%, increased gold yield from 46.95 to 63.32 g/t and reduced volume of the concentrate to be sent for the further processing by 1.33%. It is found that the basic component of the gold-carbon-sulfide concentrate is pyrite with the content С_org 1.22%. It is suggested to process the concentrate by calcination to ensure dissociation of gold-bearing sulfides and to depress carbon activity for the on-going cyanidation. The process flow diagram developed for the recovery of gold from the low-grade carbon-bearing Durminskoe ore combines the methods of the sequential flotation of carbon particles and gold-bearing sulfides and calcination of the gold-carbon-sulfide concentrate in order to neutralize sorption-active carbon, dissociate gold-bearing sulfides and improve cyanidation, and ensures the end-to-end gold recovery at the level of 90.66%.
This study has been supported by the Russian Foundation for Basic Research, Project No. 13-05-00422.

1. Zakharov B. A., Meretukov M. A. Gold: refractory ores. Moscow : "Ore and Metals" Publishing House, 2013. 451 p.
2. Meretukov M. A., Sanakulov K. S., Zimin A.V., Arustamyan M. A. Gold: chemistry for metallurgists and dressers. Moscow : "Ore and Metals" Publishing House, 2014. 412 p.
3. Lodeyshchikov V. V. Carbon in gold-beraring ores and its influence on cyanidation process. Zolotodobycha. 2008. No. 116. pp. 8–12.
4. Sedelnikova G. V. Global practice of processing of refractory gold-sulfi de ores and concentrates. Progressive methods of concentration and complex processing of natural and anthropogenic mineral raw materials. Progressive methods of concentration and complex processing of natural and technogenic mineral raw materials : collection of conference proceedings. Almaty : Izdatelstvvo AO «Tsentr nauk o Zemle, metallurgii i obogashcheniya», 2014. pp. 34–38.
5. Dunne R., Levier M., Acar S., Kappes R. Keynote Address: Newmont’s contribution to gold technology. World Gold Conference 2009. Johannesburg : The Southern African Institute of Mining and Metallurgy, 2009. pp. 221–230. Available at: http://www.saimm.co.za/Conferences/WorldGold2009/221-230_Dunne.pdf (accessed: 15.11.2016).
6. Bas A. D., Altinkaya P., Yazici E. Y., Deveci H. Preg-robbing potential of sulphide-bearing gold ores. Proceedings of the XIII^th International Mineral Processing Symposium. Bodrum, 2012. pp. 613–618. Available at: https://www.researchgate.net/publication/234111193_Preg-Robbing_Potential_of_Sulphide-Bearing_Gold_Ores (accessed: 15.11.2016).
7. Adam M., Asamoah R. K., Ofori-Sarpong G., Amankwah R. K. Preg-robbing characteristics of gold ores in Ghana. 3^rd UMaT Biennial International Mining and Mineral Conference. Tarkwa, 2014. pp. 192–196. Available at: https://www.researchgate.net/publication/270339160_Pregrobbing_Characteristics_of_Gold_Ores_in_Ghana (accessed: 15.11.2016).
8. Goodall W. R., Leatham J. D., Scales P. J. A new method for determination of preg-robbing in gold ores. Minerals Engineering. 2005. Vol. 18, No. 12. pp. 1135–1141. Available at: http://www.sciencedirect.com/science/article/pii/S0892687505001664 (accessed: 15.11.2016).
9. Rees K. L., Van Deventer J. S. J. Preg-robbing phenomena in the cyanidation of sulphide gold ores. Hydrometallurgy. 2000. Vol. 58, Iss. 1. pp. 61–80 Available at: http://www.sciencedirect.com/science/article/pii/S0304386X00001316 (accessed: 15.11.2016).
10. Dunne R., Buda K., Hill M., Staunton W., Wardell-Johnston G., Tjandrawan V. Assessment of options for economic processing of preg-robbing gold ores. Transactions of the Institutions of Mining and Metallurgy, Section C: Mineral Processing and Extractive Metallurgy. 2012. Vol. 121(4). pp. 217–223. Available at: https://www.researchrepository.murdoch.edu.au (accessed: 15.11.2016).
11. Hong-ying Yang, Qian Liu, Xiang-ling Song, Jin-kui Dong. Research status of carbonaceous matter in carbonaceous gold ores and bio-oxidation pretreatment. Transactions Nonferrous Metals Society of China. 2013. Vol. 23, Iss. 11. pp. 3405–3411. Available at: https://www.researchgate.net/publication/259520333_Research_status_of_carbonaceous_matter_in_carbonaceous_gold_ores_and_bio-oxidation_pretreatment (accessed: 15.11.2016).
12. Ofori-Sarpong G., Amankwah R. K., Osseo-Asare K. Reduction of preg-robbing by biomodified carbonaceous matter – A proposed mechanism. Minerals Engineering. 2013. Vol. 42. pp. 29–35. Available at: http://www.sciencedirect.com/science/article/pii/S0892687512003834 (accessed: 15.11.2016).
13. Gurman M. A., Aleksandrova T. N., Mamaev Yu. A. Testing of ore of moderate adsorption activity. Izvestiya vysshikh uchebnykh zavedeniy. Gornyy zhurnal. 2011. No. 1. pp. 130–134.
14. Lodeyshchikov V. V. Processing of clayey gold ores on Morro do Ouro factory (Brazil). Zolotodobycha. 2010. No. 5(144). pp. 9–13.
15. Tabatabaei R. H., Nagaraj D. R., Vianna S. M. S. M., Napier-Munn T. J., Gorain B. The effect of nonsulphide gangue minerals on the fl otation of sulphide minerals from Carlin-type gold ores. Minerals Engineering. 2014. Vol. 60. pp. 26–32.
16. Konieczny A., Pawlos W., Krzeminska M., Kaleta R., Kurzydlo P. Еvaluation of organic carbon separation from copper ore by pre-flotation. Physicochemical Problems of Mineral Processing. 2013. Vol. 49(1). pp. 189–201. Available at: http://www.minproc.pwr.wroc.pl/journal/pdf/ppmp49-1.189-201.pdf (accessed: 15.11.2016).
17. Cannon Gold Mine. Wenatchee. Washington. USA. 2013. Available at: http://www.genesbmx.com/cannon-gold-mine (accessed: 15.11.2016).
18. Emelyanov Yu. A., Bogorodskiy A. V. Balikov S. V., Epiforov A. V. The assessment of options for processing refractory fl otation concentrates. Tsvetnye Metally. 2012. No. 8. pp. 10–12.
19. Chistyakov A. A., Kovalev V. N., Galyutin A. Yu., Golikov V. V., Aksenov B. V., Rakhbani R. Jameson Cell pilot-scale fl otation testing at JSC «Albazino Resources» gold recovery plant. Obogashchenie Rud. 2014. No. 4. pp. 23–26.
20. Aleksandrova T. N., Gurman M. A., Litvinova N. M., Bogomyakov R. V. Method of flotation extraction of fine-disperse gold. Patent RF, No. 2452584. Applied: 06.07.2010. Published: 10.06.12. Bulletin No. 16.
21. Gurman M. A. Investigations of roasting of refractory clayey gol-sulfi de concentrates for further hydrometallurgical processing. Progressive methods of concentration and complex processing of natural and anthropogenic mineral raw materials : collection of conference proceedings. Almaty : Izdatelstvo AO «Tsentr nauk o Zemle, metallurgii i obogashcheniya», 2014. pp. 410–412.