What is the appropriate method for sampling stockpiles when using power equipment?

• A. Mixing and rolling out the sampling pile
• B. Back-dragging and quadrant sampling
• C. Shoveling only from the outer layer
• D. Sampling only the top layer of the pile

Answer: (B)

The appropriate method for sampling stockpiles when using power equipment involves back-dragging and quadrant sampling. This technique ensures a more representative sample by systematically collecting material from different sections of the stockpile.

Back-dragging allows the operator to remove a layer of material from the surface in a controlled manner using equipment such as a bulldozer or loader. This process helps prevent bias that might occur if sampling is only done from easily accessible areas. Quadrant sampling then divides the stockpile into sections, allowing for samples to be taken from multiple quadrants. This method increases the likelihood of reflecting the true composition of the material in the entire stockpile.

In contrast, mixing and rolling out the sampling pile may not yield a true representation, as it can introduce variation based on the mixing process. Shoveling from the outer layer alone tends to yield samples that may not accurately represent the entirety of the stockpile due to the possibility of surface segregation. Lastly, sampling only the top layer is inadequate since it overlooks the variability that may exist deeper within the stockpile. Thus, the back-dragging and quadrant sampling method provides a more comprehensive and reliable sampling strategy.