The National Coal Board Metric Methane Flow Calculator C.Z.E. Orifice Slide Rule is a piece of mining equipment designed for measuring methane flow in coal mines. This specific device is a slide rule used for calculating methane flow in metric units, making it a valuable tool for miners and engineers involved in mining operations. With its focus on mining-related activities, this calculator slide rule is a unique collectable item that showcases the theme of mining and its associated technologies.
