Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D2013 – Standard Test Method Technical Guide
ASTM D2013/D2013M-24, Standard Practice for Preparing Coal Samples for Analysis, establishes the procedures for the reduction and division of gross or divided coal samples, covering the entire process from the initial gross sample to the individual portions intended for laboratory analysis. This practice is essential for ensuring that the final analytical sample is representative of the original coal lot, minimizing bias and maintaining precision throughout the preparation stages. Originally approved in 1962, this latest edition was approved in October 2024 under the jurisdiction of ASTM Committee D05 on Coal and Coke (Subcommittee D05.23 on Sampling).
🪨 Scope and Coal Group Classification
Section 1 of the practice prescribes distinct reduction and division procedures based on the classification of the coal. The standard defines two principal groups:
- Group A: Coals that have been cleaned in all sizes. These coals benefit from the potential for a smaller retained laboratory sample weight, provided strict variance criteria are satisfied.
- Group B: All other coals, including any coals of unknown origin or treatment history. Unknown coals must always be treated under the more conservative Group B requirements.
The application of Group A sample weight reductions is strictly controlled. The user must demonstrate, using the procedures in Annex A1.2, that the combined sample preparation and analysis variance does not exceed 20 % of the total analysis variance.
🛡️ Safety and Regulatory Compliance: Per Section 1.4 of the standard, it is the responsibility of the user to establish appropriate safety, health, and environmental practices and to determine the applicability of regulatory limitations prior to use. This standard does not purport to address all safety concerns, if any, associated with its use.
⚖️ Sample Weight Requirements and Variance Criteria
A key differentiator between the coal groups is the permissible weight of the laboratory sample. Group A coals allow for a smaller retained sample mass, directly impacting the efficiency of the preparation process, but only if the precision criteria are met.
| 🟦 Feature | 📐 Group A (Cleaned Coals) | 📐 Group B (All Other Coals) |
|---|---|---|
| Coal Description | Cleaned in all sizes | All other coals, including unknown |
| Lab Sample Weight | Smaller weight permitted (subject to A1.2) | Standard weight required |
| Prep & Anal Variance Limit | Must be ≤ 20 % of total analysis variance | Standard variance protocols apply |
💡 Group A Variance Calculation Tip: When seeking the reduced weight allowance for Group A coals, rigorous adherence to the experimental design detailed in Annex A1.2 is mandatory. The calculated variance must definitively prove that the preparation stage does not dominate the overall analysis uncertainty.
🔬 Key Referenced Standards for Sample Preparation
ASTM D2013/D2013M-24 is an integral part of a larger framework of coal standards. The sample preparation procedures rely directly on established methods for gross sample collection, moisture determination, and sieve analysis. The terms used in this practice are further defined in Terminologies D121 and E456.
| 📏 Designation | ⚡ Purpose within D2013/D2013M-24 |
|---|---|
| D2234/D2234M | Practice for Collection of a Gross Sample of Coal |
| D3302/D3302M | Test Method for Total Moisture in Coal |
| D4749 | Test Method for Performing the Sieve Analysis of Coal and Designating Coal Size |
| D7430 | Practice for Mechanical Sampling of Coal |
| E11 | Specification for Woven Wire Test Sieve Cloth and Test Sieves |
❓ Frequently Asked Questions
🔍 What is the classification difference between Group A and Group B coals?
Group A explicitly includes coals that have been cleaned in all sizes. Group B serves as the default classification for all other coals, including any coals with an unknown origin or preparation history (Section 1.2).
💡 What is the key advantage of classifying a coal under Group A?
The primary advantage is the allowance for a smaller weight laboratory sample to be retained. This reduces the physical workload of sample preparation. However, it requires documented justification via Annex A1.2 showing the sample preparation and analysis variance is no more than 20 % of the total analysis variance.
⚡ What are the specific unit requirements for this standard practice?
Section 1.3 explicitly states that values stated in either SI units or inch-pound units are to be regarded separately as standard. Users must select one system and apply it consistently throughout the process. Combining values from both systems is non-conforming with the standard.
📌 Which committee governs this standard and how many division processes are described?
This practice is under the jurisdiction of ASTM Committee D05 on Coal and Coke, specifically Subcommittee D05.23 on Sampling. The Summary of Practice (Section 4) notes that three specific processes of sample division and reduction are covered.