ISO 11648-2:2001

Overview

ISO 11648-2:2001 - Statistical aspects of sampling from bulk materials - Part 2: Sampling of particulate materials defines statistical methods for taking representative samples of bulk particulate materials (ores, concentrates, coal, powders, granular chemicals, grain) from moving streams and stationary situations. The standard emphasizes dynamic sampling (moving streams) and stopped-belt sampling as the reference method, with the objective of obtaining unbiased measurements of one or more variables (chemical analysis, physical tests) and quantifying the precision of the sampling process. It does not provide acceptance-sampling decision rules.

Key topics and technical requirements

• Sampling models and terminology: Definitions for sample, sampling unit, strata, increments, bias and precision.
• Principles of sampling: One-dimensional dynamic sampling model for conveyor/stream sampling and limitations of three-dimensional static sampling (stockpiles, wagons, silos).
• Sampling schemes: How to establish schemes, choose increment mass, minimize bias, and determine number of increments and gross/sample masses.
• Sampling bases: Mass-basis sampling, time-basis sampling, and stratified random/systematic sampling within fixed intervals.
• Extraction methods: Mechanical and manual sampling from moving streams, stopped-belt sampling, and sampling from stationary situations with recommended implements.
• Sample preparation: Principles, precision and bias control, reduction for moisture, chemical analysis and physical testing.
• Measurement quality: Guidance on precision, bias assessment, packing and marking of samples.
• Informative annexes: Worked examples, sampling implements, sample preparation schemes, particle-size reduction equipment, mixers and dividers.

Applications and practical value

ISO 11648-2 is used to design and evaluate sampling programs where accurate lot characterization is critical:

• Commercial transactions and contract settlements (lot value, lot mean estimation)
• Quality control and compliance testing of bulk particulate materials
• Laboratory and field sampling procedures to reduce systematic errors (bias) and quantify random error (precision)
• Design and validation of sampling equipment (cutters, cross-belt and falling-stream samplers)
  Using the standard helps organizations produce legally and technically defensible samples for chemical analysis and physical tests.

Who should use this standard

• Mining and mineral processing engineers
• Coal and bulk commodity producers and traders
• Grain and agricultural product handlers
• Quality assurance/quality control (QA/QC) professionals and testing laboratories
• Sampling equipment manufacturers and metrologists
• Statisticians involved in sampling design

Related standards

• ISO 11648-1 (General principles)
• ISO 3534 (Statistics vocabulary)
• ISO 5725 series (Accuracy - trueness and precision)
• ISO 565, ISO 3084–3086, ISO 13909 parts, and GUM (Guide to the expression of uncertainty in measurement)