The subsampling method in which the sample is formed into a pile, spread into a disk, divided into four parts and one opposite pair is used as the laboratory sample. What is this method called?

• A. Grab sampling
• B. Coning and quartering
• C. Splitters
• D. Rotational traversing cut

Answer: (B)

Coning and quartering is a subsampling technique used to obtain a representative laboratory sample from a heterogeneous solid. The process starts by forming the material into a cone or pile, then spreading that pile into a wide, flat circular disk. The disk is then divided into four equal parts, and a sample is taken from opposite quarters to form the lab sample. This approach reduces bias from how the material is arranged and helps average out any variation across the pile, giving a sub-sample that better reflects the whole batch.

This method is distinct from grab sampling (which pulls material from a single spot), splitters (which mechanically divide a stream into parts), or rotational traversing cuts (another systematic sampling technique). The described steps specifically match coning and quartering.