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D6347 – Standard Test Method Technical Guide
📐 Standard Overview and Scope
ASTM D6347/D6347M – 05 (Reapproved 2018) defines the standard test method for determining the bulk density of stockpiled coal using instrumentation that measures the relative backscatter of nuclear gamma radiation throughout the depth of the stockpile under test. This procedure is applicable to all ranks of coal.
The standard explicitly requires that values stated in either SI units or inch-pound units be regarded separately as standard. The values in each system are not exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.
⚠️ Safety Warning: The nuclear backscatter equipment uses radioactive materials, which may be hazardous to the health of users unless proper precautions are taken. It is the responsibility of the user to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
⚙️ Test Principles and Procedural Requirements
The core principle of this test method involves deploying specialized instrumentation to measure the relative backscatter of nuclear gamma radiation throughout the depth of the coal stockpile. The density is determined as a function of this radiation attenuation, creating a comprehensive depth density profile.
Proper density determination involves an understanding of the physical characteristics of the coal types and the stockpiling facilities. Close adherence to the details of the procedures described in this standard is a prerequisite to the objective of this test method, as minor deviations can introduce cumulative errors into the final physical inventory.
💡 Best Practice Tip: Since the physical inventory derived from this method serves as the reference value for comparing and adjusting the book inventory, standardizing data collection protocols and minimizing procedural errors is critical for reliable inventory reconciliation.
| 🟦 Parameter | 📏 Specification | ⚙️ Key Data |
|---|---|---|
| Standard Designation | D6347/D6347M −05 (Reapproved 2018) | Committee D05 on Coal and Coke |
| Test Principle | Nuclear Backscatter Depth Density | Gamma Radiation |
| Applicable Materials | All Ranks of Coal | Lignite to Anthracite |
| Unit Requirements | SI or Inch-Pound Systems | Shall be used independently; shall not be combined |
| Data Integration | Physical Inventory (Tons) | Density Data × Volume (per D6172) |
📊 Data Integration and Inventory Reconciliation
Data obtained from the density of coal stockpiles using this test method is combined with volume determinations performed per Test Method D6172 to complete the physical inventory of total tons. This comprehensive physical inventory is then compared to the book inventory to determine the accumulation of measurement differences that have occurred since the last physical inventory.
This reconciliation process is fundamental for inventory control. The physical inventory serves as the definitive reference value used to compare and adjust the book inventory. The method is designed to introduce the least possible error into the measurement chain, ensuring financial accuracy in coal stockpile management.
| 🟦 Workflow Step | 📐 Process | 🎯 Associated Standard |
|---|---|---|
| 1. Density Survey | Nuclear Backscatter Depth Density Gauging | D6347 |
| 2. Volume Survey | Contour / Cross Section Photogrammetry | D6172 |
| 3. Calculation | Total Tons = Density × Volume | D6347 Introduction |
| 4. Reconciliation | Physical Inventory vs. Book Inventory Analysis | Company Inventory Procedures |
❓ Frequently Asked Questions
🔍 What is the primary purpose of ASTM D6347?
This standard covers procedures for determining the bulk density of coal using instrumentation that measures the relative backscatter of nuclear gamma radiation throughout the depth of the stockpile under test.
💡 Is this test method applicable to different grades of coal?
Yes, the procedure is specifically applicable to all ranks of coal.
⚡ How must units be reported under this standard?
Values stated in either SI units or inch-pound units are to be regarded separately as standard. The values in each system are not necessarily exact equivalents; therefore, each system shall be used independently, and values from the two systems shall not be combined.
📌 How is the density data from this test method applied?
Data obtained from the density of coal stockpiles is combined with volume determinations per Test Method D6172 to complete the physical inventory of total tons. The book inventory is then compared to this physical inventory to determine measurement differences.