ISO 6153:1989

Overview

ISO 6153:1989 - Chromium ores - Increment sampling specifies standardized methods for taking representative samples of chromium ores at points of dispatch and receipt to determine chemical composition and moisture content. Applicable to both manual and mechanical sampling of natural or processed chromium ores, the standard defines sampling plans, equipment, and procedures (including a hammer-and-shovel method in Annex A) to reduce bias and achieve required precision.

Key topics and requirements

• Purpose and scope
  • Sampling to produce increments, gross samples, sub-samples and test samples suitable for chemical and moisture analysis.
  • Applies to loading/unloading from conveyors, wagons, containers, ships and stockpiles.
• Sampling methods
  • Increment (periodic systematic) sampling, stratified sampling and two-stage sampling for wagons/containers.
  • Manual (shovels, probes, sampling frames) and mechanical (rotary-arc, bucket, cutter-chute) samplers with defined design and operational requirements.
• Equipment and minimum dimensions
  • Tools specified (increment shovels, probes) with dimensional guidance; mechanical samplers must have effective openings at least three times the nominal top size for coarse ores and meet filling/cutter-speed criteria.
• Mass and number of increments
  • Minimum increment mass depends on the nominal top size of the ore (see Table 1 in the standard).
  • The standard provides formulae and tables to calculate the number of increments required based on consignment mass, desired precision and estimated quality variation.
• Quality variation and precision
  • Classification into large or small quality variation; sampling precision and overall precision concepts are defined (with reference to ISO 8542 for precision checks).
  • Procedures to ensure near-uniform increment mass (coefficient of variation < 20%) and to protect samples from contamination.
• General rules
  • Systematic sampling with a random start, protection from contamination, sampling by qualified personnel or authorized devices, and conformance checks for bias (ISO 8541).

Practical applications and users

• Mining and bulk handling companies sampling chromium ore consignments for sale or acceptance testing
• Quality control laboratories and metallurgical analysts determining Cr2O3 content and moisture
• Port operators, commodity traders and inspection agencies responsible for dispute-free dispatch/acceptance
• Equipment manufacturers designing mechanical samplers to meet ISO requirements Using ISO 6153 helps ensure legally and commercially defensible, repeatable sampling results and reduces disputes over ore quality.

Related standards

• ISO 6154 - Chromium ores - Preparation of samples
• ISO 8541 - Methods for checking bias of sampling and sample preparation
• ISO 8542 - Experimental methods for evaluating quality variation and sampling precision
• ISO 565 - Test sieves - nominal sizes

Keywords: ISO 6153, chromium ores, increment sampling, sampling methods, sampling precision, manual sampling, mechanical sampling, sample preparation.