ISO/PWI 12745

Copper, lead and zinc ores and concentrates — Precision and bias of mass measurement techniques

Scope

ISO 12745:2008 provides guidelines to test for bias over a wide range of mass measurement techniques, to estimate the precision for each technique and to calculate the precision for wet mass when estimated by applying one of those techniques.
The guidelines are based on the application of statistical tests to verify that a mass measurement technique is unbiased, to estimate the variance as the most basic measure for its precision and to check the linearity of a static scale over its working range. Calibration methods and performance tests for compliance with applicable regulations generate test results that can be used to quantify precision and bias for each of these mass measurement techniques and to verify linearity for static weighing devices.
The guidelines apply to mass measurement techniques used to estimate the wet mass for cargoes or shipments of mineral concentrate as the basis for freight and insurance charges and for preliminary payments or for final settlements between trading partners.