Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D4916-04 – Standard Test Method Technical Guide
📐 Specimen Geometry and Types
This practice describes procedures for collecting an increment, partial sample, or gross sample of coal using mechanical augers. The specimen is a columnar sample extracted vertically from stationary loads in railcars, trucks, barges, or stockpiles. The auger increment is the retained portion from one extraction operation. A consignment is a discrete amount of coal, such as a shipment or car load. Reduction and division of the material can be performed by mechanical equipment at the auger, with further processing per Practice D2013.
⚙️ Test Procedure and Speed Selection
The mechanical auger is inserted vertically into the vehicle to extract a columnar sample. The collected coal is placed into sealed containers for storage or processed by on-line equipment like secondary samplers or crushers. The auger operation should be steady to maintain sample integrity. Reduction and division must comply with Practice D2013. The standard emphasizes that values stated in SI units are regarded as the standard.
📊 Key Measured Properties
The standard defines accuracy as the closeness of agreement between an experimental result and the true value, and precision as the capability to obtain reproducible results, expressed by variance or standard error. An unbiased sample is free of bias. These properties are essential for determining the commercial value or quality of the coal. All measurements are affected by chance errors and bias.
| 🟦 Term | 📏 Definition from ASTM D4916-04 |
|---|---|
| Accuracy | Generally, reliability of a sample, measurement, or observation. Specifically, closeness of agreement between experimental result and true value. |
| Auger Increment | The retained portion of one extraction operation of the auger. |
| Consignment | A discrete amount of coal, such as a shipment, car load, unit train, or day’s production. |
| Precision | Capability to obtain reproducible results; chance error expressed by variance, standard error, or multiple of standard error. |
| Unbiased Sample | A sample free of bias. |
Tip: For optimal results, ensure the auger is fully inserted to capture the entire depth of the load, providing a representative columnar sample.
Important: Users must establish appropriate safety and health practices and determine regulatory compliance before using this practice.