Operator Qualification rules require that each individual complete a performance verification, or a hands-on demonstration, of each task for which he/she is being qualified for. At Touchstone Training and Consulting, all performance verifications are conducted with genuine pipeline equipment and appurtenances.
One of the OQ tasks commonly performed is "Mud Plugging". In the pipeline industry, mud plugs are used during maintenance activities to seal an open-ended section of pipe after the pipeline is isolated and drained. The mud plug acts as a vapor barrier to prevent toxic or flammable vapors from escaping so that work can be completed safely.
Mud plugs are made of API Grade Bentonite, which is an absorbent clay that is purchased in powder form. The bentonite is combined with water to create a mud mixture and formed into small balls (approximately 3 inches in diameter). The mud balls are then installed in a series of rings that are pressed together and smoothed into an even surface. When the adequate length is achieved, the mud plug is tamped from the opening to ensure it is securely installed.
Check out the pictures below. They are of a recent customer performing the hands-on portion for installing a mud plug.