Author 1:
Name & Surname: Evdokimov S. I.
Company: North-Caucasian Mining and Metallurgy Institute (Vladikavkaz, Russia)
Work Position: Assistant Professor
Scientific Degree: Candidate of Engineering Sciences
Contacts: eva-ser@mail.ru

Author 2:
Name & Surname: Evdokimov V. S.
Company: North-Caucasian Mining and Metallurgy Institute (Vladikavkaz, Russia)
Scientific Degree: Postgraduate student

In view of considerable depletion of readily mineable reservoirs of high-grade ore and due to minerals and raw materials shortage, researchers and practitioners become increasingly interested in old tailings (sands) where the content of unrecovered components (beneficiation loss) exceeds cutoff grades in natural mineral deposits. Considerably lower cost of recovery, haulage and primary processing (crushing, grinding) of sands as against ledge ore will most probably balance eventual increase in the expenses connected with processing of lower grade tailings and will ensure overall profitability of marketable products. Minerals (molybdenite, fluorite, calcite) extracted from old tailings and ore at Tyrnyauz Mining-and-Processing Integrated Works have uniform properties, which allows application of the current technologies of wolfram–molybdenum ore processing. Flotation of old tailings yielded rough molybdenum concentrate with the content of 49,55% Mo at the recovery of 0,602% Mo; scheelite concentrate produced from tailings of molybdenum circuit contained 54–55% WO₃ at the recovery of 61,91–62,08% WO₃. One of the alternative circuits for processing of the tailings may be their joint flotation with ore at a ratio of 1:9. It is recommended to use jet flotation system for old tailings: initial slurry is separated into 3 flows, for example (flotation jets), rough concentrate of flow 1 is mixed with initial feed of flow 2, rough concentrate of flow 2 is mixed with initial feed of flow 3, rough concentrate of flow 3 is fed for scavenging. It is efficient to use flotation with heat saturated water steam and air mix. Nonmetallic fraction of re-processing of tailings mixed with lime has chemical composition which is similar to cement clinker, which allows its application in production of construction materials.
This study is based on research findings obtained under project “Unique Identifier of Applied Research and Experimental Developments” RFMEFI57714X0142 supported under Aid Grant Agreement No. 14.577.21.0142 dated as of November 28, 2014.

1. Chanturiya V. A., Vigdergauz V. E., Shrader E. A., Danilchenko L. M., Marchenko T. G., Sarkisova L. M., Kunilova I. V. Progressivnye (ekologicheski znachimye) tekhnologii pererabotki medno-tsinkovogo mineralnogo syrya tekhnogennykh mestorozhdeniy: problemy i resheniya (Innovative (environment-oriented) processing technologies of copper-zinc mineral raw materials of anthropogenic deposits: problems and solutions). Inzhenernaya ekologiya = Engineering ecology. 2004. No. 5. pp. 3–11.
2. Reck B. K., Graedel T. E. Challenges in metal recycling. University, New Haven, CT 06511, USA. Science. 2012. Vol. 337, No. 6095. pp. 690–695.
3. Sedelnikova G. V., Romanchuk A. I., Kim D. Kh., Savari E. E. Sovremennye tekhnologii kompleksnoy pererabotki mineralnogo syrya tsvetnykh i blagorodnykh metallov (Modern technologies of complex processing of mineral raw materials of non-ferrous and noble metals). Sovremennye metody mineralogii v protsessakh kompleksnoy i glubokoy pererabotki mineralnogo syrya : materialy Mezhdunarodnogo soveshchaniya «Plaksinskie chteniya-2012» (Modern mineralogy methods in complex and deep processing of mineral raw materials : Materials of International Meeting “Plaksin Raedings-2012”). Petrozavodsk, September 10–14, 2012. pp. 26–30.
4. Rudnev B. P. Obosnovanie i razrabotka effektivnykh metodov obogashcheniya tekushchikh i lezhalykh khvostov obogashcheniya rud tsvetnykh, blagorodnykh i redkikh metallov : avtoreferat dissertatsii … doktora tekhnicheskikh nauk (Substantiation and development of efficient concentration methods of current and stale concentration tails of non-ferrous, noble and rare metal ores : thesis of inauguration of Dissertation … of Doctor of Engineering Sciences). Moscow : Gintsvetmet, 2004. 162 p.
5. Bian Zhengfu, Miao Xiexing, Shaogang Lei, Chen Shen-en, Wang Wenfeng, Struthers Sue. The challenges of reusing mining and mineral-processing wastes. Science. 2012. Vol. 337, No. 6095. pp. 702–703.
6. Danilkin A. A., Ivanovskiy S. V., Reshetnyak S. P., Semkin S. V., Komyagin A. O. Osnovnye itogi i uroki realizatsii krupnomasshtabnogo proekta osvoeniya tekhnogennogo mestorozhdeniya otkhodov obogatitelnogo proizvodstva (Main results and lessons of realization of large-scale project of mastering of anthropogenic deposit of concentration industry wastes). Gornyi Zhurnal = Mining Journal. 2012. No. 10. pp. 40–44.
7. Kobozev M. A., Simonovskiy A. Ya. Metod izmereniya, eksperimentalnaya ustanovka i rezultaty izmereniya chastoty obrazovaniya puzyrkov para pri kipenii magnitnoy zhidkosti na odinochnom tsentre paroobrazovaniya (Measurement method, experimental apparatus and results of measurement of steam bubble formation frequency during magnetic liquid boiling on a single steam formation center). Zhurnal tekhnicheskoy fiziki = Technical Physics. 2007. Vol. 77, No. 11. pp. 31–38.
8. Panshin A. M., Evdokimov S. I. Rezultaty obogashcheniya rud Olimpiadinskogo mestorozhdeniya po skheme struynoy flotatsii i aeratsii pulpy aerozolem (Results of ore concentration of Olimpiada deposit according to the scheme of stream flotation and aeration of pulp by aerosol). Obogashchenie Rud = Mineral processing. 2011. No. 6. pp. 8–12.
9. Kvitka V. V., Kushakova L. B., Yakovleva E. P. Pererabotka lezhalykh khvostov obogatitelnykh fabrik Vostochnogo Kazakhstana (Processing of stale tails of Eastern Kazakhstan concentration plants). Gornyi Zhurnal = Mining Journal. 2001. No. 9. pp. 57–61.
10. Evdokimov S. I., Datsiev M. S., Podkovyrov I. Yu. Razrabotka novoy skhemy i sposoba flotatsii rud Olimpiadinskogo mestorozhdeniya (Development of new scheme and method of flotation of Olimpiada deposit ores). Izvestiya vuzov. Tsvetnaya metallurgiya = Russian Journal of Non-ferrous Metals. 2014. No. 1. pp. 3–11.
11. Panshin A. M., Evdokimov S. I. Struynaya flotatsiya v usloviyakh spetsialno formiruemogo vysokogo soderzhaniya metallov v iskhodnoy rude (Stream flotation in the conditions of speciallyformed high content of metals in base ore). Obogashchenie Rud = Mineral processing. 2009. No. 5. pp. 6–10.
12. Samatova L. A., Shepeta E. D., Gvozdev V. I. Mineralogo-tekhnologicheskie svoystva i obogashchenie bednykh sheelitovykh rud Primorya (Mineralogical-technological properties and concentration of poor scheelite ores of Primorye). Fiziko-tekhnicheskie problemy razrabotki poleznykh iskopaemykh = Journal of Mining Science. 2012. No. 3. pp. 152–161.
13. Perepelkin K. E., Matveev V. S. Gazovye emulsii (Gas emulsions). Leningrad : Khimiya, 1979. 200 p.
14. Rubinshteyn Yu. B., Filippov Yu. A. Kinetika flotatsii (Flotation kinetics). Moscow : Nedra, 1980. 375 p.
15. Evdokimov S. I., Panshin A. M. Poverkhnostnye sily v protsessakh agregatsii i flotatsii chastits (Surface forces in the processes of aggregation and flotation of particles). Izvestiya vuzov. Tsvetnaya metallurgiya = Russian Journal of Non-ferrous Metals. 2009. No. 3. pp. 7–11.
16. Panshin A. M., Evdokimov S. I., Artemov S. V. Issledovaniya v oblasti flotatsii parovozdushnoy smesyu (Research in steam-air mixture flotation area). Izvestiya vuzov. Tsvetnaya metallurgiya = Russian Journal of Non-ferrous Metals. 2012. No. 1. pp. 3–10.