Gipronikel Institute LLC, Saint Petersburg, Russia:

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

Kola MMC, Monchegorsk, Russia:
M. S. Molodtsev, Chief Engineer at the Mineral Processing Plant
A. M. Kazakov, Supervisor, Quality Control Department, Control and Analysis Centre
L. A. Brazyulis, Supervisor, Mineral Concentration, R&D Department, Control and Analysis Centre

Kola MMC’s Mineral Processing Plant has optimized its product quality control system designed to monitor the mass concentration of non-ferrous metals in the commercial products: i.e. the finished concentrate and the final tailings. Thus, automatic samplers and dividers of Sections 1, 2 and 3 have been made fully conforming with GOST 14180–80; through experiments, variation coefficients have been determined, which were used to specify the homogeneity class for the concentrate and the tailings; operating parameters have been defined for the sampling and sample preparation equipment; through experiments, intermediate precision mean square deviations (S_опр) and intermediate precision limits (R_Lопр) have been determined. Measurement procedures have been developed that were certified by Rosstandart, Russia’s Federal Agency for Technical Control and Metrology.

1. GOST 14180–80. Ores and concentrates of non-ferrous metals. Methods of sampling and preparation of samples for chemical analysis and determination of moisture. Introduced: 01.07.1987.
2. Glazatov A. N., Spitsyn N. K., Kazakov A. M., Novikov M. N., Sokolov S. V. Control of overspills after classification in beneficiation production at “Kola mining metallurgical company”. Tsvetnye Metally. 2010. No. 12. pp. 20–23.
3. Guidelines: I 2-48200234-22/45-02–2015. Mineral processing product sampling and sample preparation. Introduced: 25.08.2015.
4. Measurement procedures: MVI 04-60-138–2009. Mineral processing plant products. Determining the mass concentration of nickel, copper and cobalt by means of X-ray fluorescence spectrometry. Introduced: 30.03.2009.
5. Rumshinskiy L. Z. Mathematical processing of experimental results. Moscow : Nauka, 1971. 192 p.
6. Agekyan T. A. Fundamentals of the error theory for astronomers and physicists. Moscow : Nauka, 1972. 172 p.
7. Novitskiy P. V., Zograf I. A. Measurement error analysis. Leningrad : Energoatomizdat, 1991. 304 p.
8. Broshot S. Sampling for metallurgical research: how the results of the GRG test can be used to assess their level of reliability. Proceedings of the IMPC XXVIII Conference. Quebec, Canada, September 2016. Vol. 1. pp. 612–623.
9. Thompson M., Ramsey M. H. Quality concepts and practice applied to sampling — an exploratory study. Analyst. 1995. Vol. 120. pp. 261–270.
10. ISO 12743:2018. Concentres de cuivre, de plomb, de zinc et de nickel – Procedures d’echantillonnage pour la determination de la teneur en metal et de I’humidite. Published: 15.06.2006.
11. ISO 21748:2017. Guidance for the use of repeatability, reproducibility and trueness estimates in measurement uncertainty evaluation. Published: 04.2017.
12. Ramsey M. H., Ellison S. L. R. Rostron P. Eurachem/EUROLAB/CITAC/Nordtest/AMC Guide: Measurement uncertainty arising from sampling: a guide to methods and approaches. Second Edition, Eurachem, 2019. 109 р.
13. Haolun Shi, Guosheng Yin. Reconnecting p-value and posterior probability under one- and two-sided tests. The American Statistician. 2020. DOI: 10.1080/00031305.2020.1717621.
14. Khalil A., Salahuddin M. W. K., Shafiq M., Hassan S. et al. New advanced outliers detection tests. Communications in Statistics — Theory and Methods. 2020. DOI: 10.1080/03610926.2020.1741630.
15. Wenger K., Less V. A modified Wilcoxon test for change points in long-range dependent time series. Economics Letters. 2020. Vol. 192. DOI: 10.1016/j.econlet.2020.109237.