Which technique is primarily used by a highly experienced operator to detect unmarked pipes through bucket contact?

The correct answer is bucket movement. Highly experienced operators utilize subtle variations in the way they move the bucket to detect unmarked pipes and underground utilities. By carefully manipulating the bucket, operators can feel for resistance or changes in material that may indicate the presence of a buried pipe. This technique requires skill and a deep understanding of how the equipment interacts with different types of ground conditions.

While control, total concentration, and careful digging are certainly important aspects of operating heavy machinery, they do not specifically focus on the technique used to identify hidden utilities like bucket movement does. Control refers to the overall management of the machine’s functions, which is vital for safe operation but not directly related to detecting pipes. Total concentration involves the operator’s mental focus, which supports overall performance but does not define a specific technique for detecting pipes. Careful digging is a good practice to reduce the risk of damage, but it encompasses a broader approach and is not as specific in identifying underground utilities as the strategic movements of the bucket.