ASTM D7256/D7256M-08 PDF

Full title and description

Standard Practice for Mechanical Collection and Within-System Preparation of a Gross Sample of Coal from Moving Streams — designated ASTM D7256/D7256M-08. The practice describes procedures for mechanically collecting gross samples from moving coal streams and for within-system preparation (reduction and division) of those gross samples so they are suitable for subsequent laboratory analysis and classification.

Abstract

ASTM D7256/D7256M-08 provides recommended mechanical sampling procedures for moving streams of coal, including increment collection methods (time- or mass-based), falling-stream and cutter samplers, and within-system sample reduction and division techniques. The standard is intended to ensure representative gross samples for further preparation and testing under established sampling classifications.

General information

• Status: Withdrawn — replaced by ASTM D7430 (mechanical sampling of coal).
• Publication date: April 15, 2008 (designation D7256/D7256M-08).
• Publisher: ASTM International (American Society for Testing and Materials).
• ICS / categories: Coals — ICS code 73.040 (coal sampling and related methods).
• Edition / version: D7256/D7256M-08 (2008 edition).
• Number of pages: 6 pages (brief practice format).

Scope

The practice covers mechanical collection of gross samples from moving streams of coal under sampling classifications (I‑B‑1 and I‑B‑2 per Practice D2234/D2234M) and the within-system reduction and division of those gross samples using mechanical sampling-system components. It addresses procedures by coal size and preparation condition (for example, raw coal or mechanically cleaned coal) and gives guidance on increment spacing (systematic or random) and sampler design to minimize bias. The practice does not cover every safety consideration related to sampling operations.

Key topics and requirements

• Definitions and classification references for gross sampling (ties to Practice D2234/D2234M).
• Requirements for increment collection from moving streams: systematic or random spacing, time- and mass‑based increment distribution.
• Sampler types and design considerations (falling-stream cutters, falling-stream samplers) and recommended motion/velocity to avoid selective rejection or contamination.
• Within-system sample preparation: reduction and division methods to produce working samples from the gross sample.
• Unit systems: both SI and inch‑pound units are provided (each system to be used independently).
• Advisory notes on sample representativeness, planning of sampling operations, and safety responsibilities for users.

Typical use and users

This practice was intended for use by coal producers, power plants, coke and coal traders, laboratories performing coal analysis, designers and installers of mechanical sampling systems, and regulators interested in standardized, repeatable sampling procedures for moving coal streams. It supports procurement, quality control, valuation, and environmental/emissions testing workflows that depend on representative coal samples.

Related standards

Key related documents include Practice D2234/D2234M (classification of sampling and sampling plans), Practice D2013/D2013M (further sample preparation for petrographic analysis), and the consolidated Standard Practice for Mechanical Sampling of Coal, ASTM D7430 (which incorporates and replaces D7256/D7256M along with several other sampling practices). Other historically associated practices include D4916, D4702, and D6518 which are addressed in the D7430 consolidation.

Keywords

coal sampling; mechanical sampling; gross sample; moving stream; falling-stream sampler; increment; sample reduction; sample division; D7256; D7256/D7256M; coal quality; representative sampling.

FAQ

Q: What is this standard?

A: ASTM D7256/D7256M-08 is a brief practice describing mechanical collection and within‑system preparation of a gross sample of coal from moving streams (designation published in 2008).

Q: What does it cover?

A: It covers procedures for collecting increments from moving coal streams, sampler design considerations (for example falling‑stream cutters), systematic and random increment spacing, and methods for reducing and dividing gross samples within the sampling system so they can be prepared for laboratory analysis.

Q: Who typically uses it?

A: Coal producers, utilities, traders, laboratories, sampling equipment suppliers, and regulatory or inspection bodies that require standardized mechanical sampling methods to produce representative coal samples.

Q: Is it current or superseded?

A: It has been withdrawn and was replaced by the consolidated practice ASTM D7430 (Mechanical Sampling of Coal). The ASTM record indicates D7256/D7256M was withdrawn and superseded by D7430; users should refer to the current D7430 edition for up‑to‑date, consolidated sampling requirements.

Q: Is it part of a series?

A: D7256/D7256M was one of several ASTM sampling practices for coal; its content was incorporated into the multi‑part D7430 practice (which combines the scopes of D7256/D7256M, D4916, D4702, and D6518).

Q: What are the key keywords?

A: Representative sampling, gross sample, moving stream, mechanical sampler, increment collection, sample reduction, falling‑stream cutter, coal sampling.