Sampling method for solids

Front

Sampling from Conveyor Belts

Back

Sampling from a conveyor belt is used to get a representative sample from a moving stream of solid material. The key is to cut the entire stream of material as it discharges from the conveyor. This is often done using a cross-belt cutter or a sampling cup that passes horizontally through the falling stream. This method ensures all parts of the material flow are equally likely to be included in the sample, which is vital for getting a representative sample of a changing material, such as ore or coal.

Front

Thiefs

Back

A thief is a specialized sampling tool used to collect a sample from a static pile or container of fine particulate solids, like powders or grains. The tool is a long tube, often with a pointed end, that can be inserted into the material. It has slots or chambers along its length that can be opened and closed to capture material at specific depths.

Front

Auger

Back

An auger is a helical tool used to collect samples from compact, cohesive solids like soil or granular materials in bags or containers.

Front

Sub-sampling Using Coning and Quartering

Back

Coning and quartering is a manual method for reducing the size of a large, bulk solid sample while maintaining its representativeness.

• Procedure: First, you thoroughly mix the large sample and form it into a conical pile. The pile is then flattened into an even, circular cake. This cake is then divided into four equal quadrants using a shovel or a spatula. You then discard two opposite quarters and combine the remaining two. This process is repeated until you achieve a sub-sample of the desired size. While simple and effective for very large samples, it can be prone to human error and particle segregation.

Front

Riffling

Back

Riffling is a more accurate and precise method for sub-sampling than coning and quartering. A riffle splitter (also called a riffle divider) is a device that uses a series of chutes to divide a sample.

• Procedure: The bulk sample is poured into the top of the riffle splitter. The chutes are arranged in alternating directions, randomly distributing the material into two separate collection pans. This process effectively halves the sample size. You repeat this process with one of the new samples until you reach the required amount for analysis. This method minimizes segregation and provides a more statistically representative sub-sample.