Gipronikel Institute LLC, Saint Petersburg, Russia:

A. N. Glazatov, Lead Researcher at the Pyrometallurgical Laboratory, Candidate of Technical Sciences, e-mail: glazatovAN@nornik.ru

Medvezhiy Ruchey LLC, Norilsk, Russia:
V. Yu. Lunev, Chief Engineer

MMC Norilsk Nickel, Moscow, Russia:
E. V. Parievskiy, Head of the Science and Technology Directorate, Production Office, Production Department

MMC Norilsk Nickel’s Polar Division, Norilsk, Russia:
E. V. Danchenko, Deputy Head of the Science and Technology Directorate

To validate the result of incoming inspection with regard to the blend of crushed high-grade cupriferous and disseminated ores coming from Oktyabrsky, Taymyrsky and Komsomolsky (Skalistaya mine) pits, a comparative test was conducted to determine the weight fractions of nickel, copper and sulphur. The test was conducted on the sample preparation plant located in the crusher building of Talnakh Concentrator per GOST R ISO 11648-2–2009 by means of minimum-shift sampling. Two separate sampling techniques were used on the functioning conveyors designated as A and B for the purposes of this paper. The techniques include the existing one based on the use of automatic bucket sampler and a technique when a standard sample is collected with a template directly from the conveyor belt that gets stopped once the bucket sampler has activated. The average divergence indicators obtained for samples d Ni , d Cu and d S are situated close to zero and are equal to 0.045; –0.016; 0.042 and 0.047; 0.014; 0.191 wt. % for conveyors A and B, correspondingly. It is demonstrated that all the values in the analyzed samples conform with the normal distribution law. T-test revealed no systematic discrepancies, which proves that there is no difference between the two sampling techniques. It means that the divergence indicators obtained belong to the same general population, and this proves the correctness of the sampling performed and the effectiveness of the existing incoming ore inspection system. Based on the experimental data and per OST 41-08-212–04, allowable error values were determined for Category III techniques. Based on the above values, allowable divergence values were calculated between two test results, with the confidence figure Р = 0.95 (of the repeatability limit). The values are 0.29, 0.33 and 0.82% for nickel, copper and sulphur, respectively.

The authors would like to thank Mr. N. Yu. Enikeev, chief metrologist at Gipronikel Institute, for advisory support; shift supervisors, dispatchers and crusher personnel of Talnakh Concentrator for conducting preparation, commissioning and experimental work, as well as leaders and personnel of the Analytics Directorate for their work with the samples.

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