ISO/TC 183/WG 9 - Sampling of copper, lead and zinc concentrates

This document sets out the basic methods for sampling copper, lead, zinc and nickel concentrates from moving streams and stationary lots, including stopped-belt sampling, to provide samples for chemical analysis, physical testing and determination of moisture content, in accordance with the relevant International Standards. Where the concentrates are susceptible to significant oxidation or decomposition, a common sample that is sufficiently representative, i.e. unbiased and sufficiently precise, is used for moisture determination and chemical analysis to eliminate bias (see ISO 10251). Any large agglomerates (>10 mm) present in the primary sample are crushed prior to further sample processing. Sampling of concentrates in slurry form is specifically excluded from this document. Stopped-belt sampling is the reference method for collecting concentrate samples against which mechanical and manual-sampling procedures can be compared. Sampling from moving streams is the preferred method. Both falling-stream and cross-belt samplers are described. Sampling from stationary lots is used only where sampling from moving streams is not possible. The procedures described in this document for sampling from stationary lots only minimize some of the systematic sampling errors.

ISO 11794:2017 sets out the basic methods for sampling particulate material that is mixed with a liquid, usually water, to form a slurry. In industry and in the mining and mineral processing literature, slurry is also referred to as pulp, but this term is not used in ISO 11794:2017. At very high ratios of fine particulate solids to liquids where material assumes a soft plastic form, the mixture is correctly termed as a paste. Sampling of pastes is not covered in ISO 11794:2017. The procedures described in ISO 11794:2017 apply to sampling of particulate materials that are transported in moving streams as slurries, but not pressurized slurries. These streams may fall freely or be confined in pipes, launders, flumes, sluices, spirals or similar channels. Sampling of slurries in stationary situations, such as a settled or even a well-stirred slurry in a holding vessel or dam, is not recommended and is not covered in ISO 11794:2017. ISO 11794:2017 describes procedures that are designed to provide samples representative of the slurry solids and particle-size distribution of the slurry under examination. After draining the slurry sample of fluid and measuring the fluid volume, damp samples of the contained particulate material in the slurry are available for drying (if required) and measurement of one or more characteristics in an unbiased manner and with a known degree of precision. The characteristics are measured by chemical analysis, physical testing or both. The sampling methods described are applicable to slurries that require inspection to verify compliance with product specifications, determination of the value of a characteristic as a basis for settlement between trading partners or estimation of a set of average characteristics and variances that describes a system or procedure. Provided that flow rates are not too high, the reference method against which other sampling procedures are compared is one where the entire stream is diverted into a vessel for a specified time or volume interval. This method corresponds to the stopped-belt method described in ISO 12743.

ISO 11790:2017 sets out recommended practices for the inspection of mechanical sampling systems. It serves as a reference for conformance with applicable International Standards for copper, lead, zinc and nickel concentrates. ISO 11790:2017 covers general considerations, including precision, quality variation, bias, establishment of inspection systems and inspection procedures.

ISO 13543:2016 specifies the method for determining the mass of contained metal in a lot, based on the wet mass, moisture content and dry basis metal content of the lot. The procedure for estimating the variance and confidence intervals for the mass of contained metal is also specified.

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.

ISO 10251:2006 specifies methods for the determination of moisture content of a lot of copper, lead, zinc or nickel concentrate, defined as the percentage mass loss of the moisture test portion under the conditions of drying specified in this document. ISO 10251:2006 is not applicable to drying samples used for determination of volatile elements such as mercury and sulfur.

ISO 12744:2006 specifies methods for checking the precision of primary sampling, sample processing, chemical analysis, physical testing and determination of moisture content of copper, lead, zinc and nickel concentrates being carried out in accordance with the methods specified in ISO 12743, expressed in terms of standard deviations.

ISO 13292:2006 specifies methods for checking whether there is any bias in the sampling of copper, lead, zinc and nickel concentrates, where the sampling is carried out in accordance with the methods specified in ISO 12743. These methods can also be used for comparing alternative sampling regimes, checking whether there is any bias in sample processing and for checking possible significant differences in sampling at different places, e.g. at loading and discharge points, or the analysis of exchange samples.

This document sets out the basic methods for sampling copper, lead, zinc and nickel concentrates from moving streams and stationary lots, including stopped-belt sampling, to provide samples for chemical analysis, physical testing and determination of moisture content, in accordance with the relevant International Standards. Where the concentrates are susceptible to significant oxidation or decomposition, a common sample that is sufficiently representative, i.e. unbiased and sufficiently precise, is used for moisture determination and chemical analysis to eliminate bias (see ISO 10251). Any large agglomerates (>10 mm) present in the primary sample are crushed prior to further sample processing. Sampling of concentrates in slurry form is specifically excluded from this document. Stopped-belt sampling is the reference method for collecting concentrate samples against which mechanical and manual-sampling procedures can be compared. Sampling from moving streams is the preferred method. Both falling-stream and cross-belt samplers are described. Sampling from stationary lots is used only where sampling from moving streams is not possible. The procedures described in this document, for sampling from stationary lots, only minimize some of the systematic sampling errors.

ISO 11794:2010 sets out the basic methods for sampling particulate material that is mixed with a liquid, usually water, to form a slurry. In industry and in the mining and mineral processing literature, slurry is also referred to as pulp, but this term is not used in ISO 11794:2010. At very high ratios of fine particulate solids to liquids where material assumes a soft plastic form, the mixture is correctly termed as a paste. Sampling of pastes is not covered in ISO 11794:2010. The procedures described in ISO 11794:2010 apply to sampling of particulate materials that are transported in moving streams as slurries, but not pressurized slurries. These streams may fall freely or be confined in pipes, launders, flumes, sluices, spirals or similar channels. Sampling of slurries in stationary situations, such as a settled or even a well-stirred slurry in a holding vessel or dam, is not recommended and is not covered in ISO 11794:2010. ISO 11794:2010 describes procedures that are designed to provide samples representative of the slurry solids and particle-size distribution of the slurry under examination. After draining the slurry sample of fluid and measuring the fluid volume, damp samples of the contained particulate material in the slurry are available for drying (if required) and measurement of one or more characteristics in an unbiased manner and with a known degree of precision. The characteristics are measured by chemical analysis, physical testing or both. The sampling methods described are applicable to slurries that require inspection to verify compliance with product specifications, determination of the value of a characteristic as a basis for settlement between trading partners or estimation of a set of average characteristics and variances that describes a system or procedure.

ISO 11790:2010 sets out recommended practices for the inspection of mechanical sampling systems. It serves as a reference for conformance with applicable International Standards for copper, lead, zinc and nickel concentrates. ISO 11790:2010 covers general considerations, including precision, quality variation, bias, establishment of inspection systems and inspection procedures.

ISO 12743:2006 sets out the basic methods for sampling copper, lead, zinc and nickel concentrates from moving streams and stationary lots, including stopped-belt sampling, to provide samples for chemical analysis, physical testing and determination of moisture content, in accordance with the relevant International Standards.