Ural State Mining University (Ekaterinburg, Russia):
Kozin V. Z., Head of Chair, Doctor of Engineering Sciences, Professor, gmf.dek@ursmu.ru
Komlev A. S., Senior Researcher, Candidate of Engineering Sciences, tails2002@inbox.ru

Irgiredmet (Irkutsk, Russia):
Stupakova E. V., Head of Department

Random errors when testing ores and processing products at concentration plants are established experimentally. The method for determining such errors is based on duplicate testing, when the estimate of the root mean square value of the random error is calculated by the range of parallel analyzes. The practical use of the range of duplicate mass fraction values in assessing random sampling errors for a small number of duplicate analyzes under GOST 14180-80 leads to significant random and probable systematic errors. The main cause of duplicate sampling errors is the low probability of large range occurrences, and therefore, for the actual number of duplicate analyzes (ten according to standard), the experimentally obtained variance estimates are underestimated by 20 % and are additionally characterized by relative random errors in the range from +70 to –40 %. Duplicate testing with a large number of ranges used in the calculation (400–800) leads to correct estimates of the testing errors. The recommendations of testing standards and the methods for establishing the sampling errors at enterprises must be changed either to increase the number of ranges used by one or two orders of magnitude or to replace duplicate testing by direct establishment of variances using the existing theoretical formulas.

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