The parts of a quarry or mine that are being (or has been) worked(noun)
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Use "workings" in a sentence
"For six months I have read with close attention your story of "Frenzied Finance," in _Everybody's Magazine_, and have paid close attention to the manner in which, by pandering to the worst prejudices of the American people, you have endeavored by misstatement of facts to distort the conditions actually existing through what you call the workings of the "System.""
"An understanding of the ribosome's innermost workings is important for a scientific understanding of life."
"The conveyor belt model is an important component of our understanding of the long-term workings of the climate."