When sampling from a stockpile, which option describes how to obtain the sample from the horizontal surface relative to the intersection of horizontal and vertical faces?

• A. From the vertical face far from the intersection
• B. From the horizontal surface as close as possible to the intersection of horizontal and vertical faces
• C. From the center of the horizontal surface only
• D. From the outer surface of the pile

Answer: (B)

The main idea is to get a sample that truly represents the material in the stockpile, not just a biased slice from one spot. Sampling from the horizontal surface as close as possible to where the horizontal and vertical faces meet gives material that has mixed from different parts of the pile and across a cross-section, reducing the effects of surface segregation or edge-only bias. The top surface alone can be segregated, and taking from a distant vertical face or the pile’s center can miss variations within the pile or introduce contamination from the pile’s edge. Sampling near that intersection captures a more representative blend of particle sizes and moisture conditions, making it the best choice for a representative stockpile sample.