1.2.1 Part A describes mechanical sampling procedures for coals (1) by size and condition of preparation (for example, mechanically cleaned coal or raw coal), and (2) by sampling characteristics.

1.2.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

1.3.1 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4.1 Spacing of increments pertains to the kind of interval between increments. Intervals can be defined in quantitative terms, such as units of time or mass, or in terms of position over the lot.

1.4.2 Spacing of Increments for Cross-Belt and Falling Stream Samplers—Cross-belt and falling stream type mechanical sampling systems take increments based on time, either at fixed time intervals or at random times during a fixed time strata. Some falling stream samplers can take increments based on equal mass of coal sampled as determined by scales. The sections of this practice that pertain to cross-belt and falling stream samplers describe procedures for only time-based sampling systems. This time-based inspection guideline will satisfy most criteria for mass-based or combination mass-based and time-based sampling systems. If there are items that are not covered, the inspector should refer to the manufacturer's literature.

1.4.3 Spacing of Increments for Auger Sampling—The spacing of increments collected by auger sampling systems is defined in terms of position over the lot.

1.4.4 It is essential that the inspector have the documentation listed in Section 2 of this practice when conducting an inspection.

1.4.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.5.1 Part D does not purport to define an absolute bias. Bias defined by this practice is the difference between the population mean of the mechanical sampler test results and the accepted reference value.

1.5.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.