What production sampling method requires approval from IDOT before use?

The Bin Discharge sampling method requires approval from IDOT before use because it involves taking samples directly from a stockpile or bin, which can introduce variability based on how the material is distributed or layered within the storage unit. This method can lead to non-representative samples if not conducted properly, making it essential that the procedure is outlined and approved by IDOT to ensure that the sampling meets specific standards and protocols. This oversight helps maintain quality control in the production of aggregates and ensures compliance with the established guidelines for testing.

In contrast, other sampling methods like Continuous Sampling, Random Sampling, and Composite Sampling have established procedures that may not require individual approval, as they typically follow more standardized practices for collecting representative samples.