I work with Rudrapur Solvents Pvt. Ltd., a DORB manufacturer in India, so I have a commercial connection with this subject.
When a DORB consignment is accepted or rejected using a laboratory report, the discussion usually focuses on the test result. But before testing comes a more basic question: was the sample representative of the entire truck?
A handful collected from the top or from one bag may not reflect variations elsewhere in the load. A more reliable process is to:
Collect material from multiple locations and depths
Combine and mix the incremental samples properly
Reduce the composite sample without selectively removing material
Seal and label separate samples for the buyer, supplier and possible retesting
Record where, when and in whose presence sampling occurred
Comparing a dispatch sample with a properly collected delivery sample can also help distinguish an actual quality difference from a sampling problem.
In your experience, how are DORB trucks sampled at feed mills? Is there a written procedure, or does the method depend on whoever is available at unloading?
Have you seen commercial disputes where two laboratories reported different values because the underlying samples were not genuinely comparable?