ISO 20904-2020 PDF

Full title and description

ISO 20904:2020 — Hard coal — Sampling of slurries. This International Standard specifies methods for taking representative samples of fine hard coal, coal rejects or tailings (nominal top size < 4 mm) when mixed with water to form a slurry. The standard describes procedures intended to provide samples representative of slurry solids and particle size distribution for subsequent drying, chemical analysis or physical testing.

Abstract

ISO 20904:2020 sets out basic sampling methods for fine coal slurries transported in moving streams (open channels, pipes, launders, chutes, spirals and similar). It excludes sampling of pastes (very high solids/water ratio where material is plastic) and does not cover settled or stationary slurries in tanks, holding vessels or dams. The document describes reference and comparative sampling procedures (including full-stream diversion where feasible), draining and handling of slurry samples to produce damp solid samples for drying and analysis, and is intended for specification verification, trading settlement and estimation of average characteristics and variances.

General information

• Status: Published (International Standard)
• Publication date: 28 February 2020
• Publisher: International Organization for Standardization (ISO)
• ICS / categories: 73.040 (Coal)
• Edition / version: Edition 2, 2020
• Number of pages: 35

Scope

This standard applies to sampling fine hard coal and related solids (nominal top size < 4 mm) when mixed with water to form a flowing slurry. It covers moving stream situations (free-falling streams or streams confined in pipes, launders, chutes, spirals or similar channels) and describes methods to obtain representative samples of the solids and their particle size distribution. Sampling of pastes (very high solids content producing a plastic material) and of stationary or settled slurries in tanks or dams is excluded. The procedures are intended for quality control, contractual verification and establishment of average properties and variances of slurry solids.

Key topics and requirements

• Definition of slurry and exclusion of paste and stationary/settled slurries.
• Requirements for representative sampling of moving slurry streams (nominal top size < 4 mm).
• Reference sampling method: full-stream diversion (stopped-belt / whole-stream collection) where flow rates permit.
• Practical sampling techniques for confined and free-falling slurry streams (pipes, launders, chutes, spirals, etc.).
• Procedures for draining fluid from the collected sample and producing damp solid samples suitable for drying and subsequent chemical/physical testing.
• Guidance on reducing bias and estimating precision (variance) of sampling results for specification verification and trading settlement.
• Requirements for sample handling, containerization and record keeping to preserve representativity.

Typical use and users

Used by coal mine and processing plant technical staff, process engineers, laboratory personnel, quality/inspection teams, trading and contract managers, independent sampling and testing laboratories, and regulatory or environmental monitoring bodies. Typical applications include incoming/outgoing product inspection, tailings and reject monitoring, contractual settlement between buyers and sellers, and process control where slurry composition and particle-size distribution are important.

Related standards

Closely related to other coal sampling and testing standards (for example the ISO/TC 27 series on sampling of coal and coke). The reference (full-stream / stopped-belt) method is aligned with practices described in sampling standards such as ISO 13909 series. National adoptions and identical publications (e.g., BS ISO 20904:2020) and the earlier ISO 20904:2006 edition are also relevant for historical comparison and transitional use.

Keywords

hard coal; slurry sampling; coal tailings; representative sample; sampling procedure; particle size distribution; slurry solids; ISO 20904; QA/QC; trading settlement; sample draining

FAQ

Q: What is this standard?

A: ISO 20904:2020 is an International Standard that specifies methods for sampling fine hard coal and related solid material mixed with water to form slurries, with the aim of obtaining representative samples for analysis and testing.

Q: What does it cover?

A: It covers sampling procedures for moving slurry streams (pipes, launders, chutes, spirals and free-falling streams) for materials with nominal top size < 4 mm. It describes reference and practical sampling methods, sample draining and handling, and guidance on representativity and precision. It excludes pastes and settled or stationary slurries in tanks or dams.

Q: Who typically uses it?

A: Coal producers, processing plants, laboratory technicians, QA/QC teams, independent inspectors, contract managers and environmental/regulatory agencies use this standard for quality control, trading settlement and process monitoring.

Q: Is it current or superseded?

A: This is the second edition published in 2020 and supersedes the 2006 edition. It is published and in force; like all ISO standards it is subject to periodic review (typically every five years).

Q: Is it part of a series?

A: It sits alongside other ISO standards on sampling and testing of coal and coke (ISO/TC 27 work) and makes reference to related sampling methods such as those in the ISO 13909 series. National identical/adopted versions (e.g., BS ISO 20904:2020) may also exist.

Q: What are the key keywords?

A: hard coal, slurry sampling, sampling procedure, representative sample, particle size distribution, tailings, QA/QC, ISO 20904.