June 13, 2026
North American Coal Operation: Engineering Measurement Confidence for Coal Blending
A recent belt scale installation at a North American coal operation demonstrates why understanding the true performance of an existing weighing system is often the first step towards improving measurement accuracy.
The operation relied on belt scale data to blend different coal grades, believing its legacy system was achieving ±0.25% accuracy. However, CST’s site audit found the system was actually operating with between 9% to 16% error, introducing significant uncertainty into blending decisions and the commercial calculations based on that data.
The assessment also identified the site’s existing tail pulley tachometer as a major contributor to the measurement error. While attention is often focused on the weigh frame, belt speed measurement is equally important—a 1% tachometer error results in a 1% error in the overall belt scale measurement. Understanding how each component contributes to total system performance enabled CST to accurately assess the site’s achievable accuracy.
CST worked closely with the customer to explain the existing system’s limitations, the operational constraints of the application and the engineering decisions behind the proposed solution. The final design included upgrading from a four-idler weigh frame to a five-idler zero-deflection weigh frame and replacing the tachometer with a TD MICRONIC unit better suited to the application’s accuracy requirements. CST also explained how the site’s reclaimer configuration introduced inherent measurement limitations, allowing an achievable accuracy of ±0.35% and a guaranteed system accuracy of ±0.5% to be established.
The result is a belt weighing system the operation can trust, providing reliable measurement data to support coal blending, production reporting and commercial decision-making. More importantly, the project demonstrates CST’s engineering philosophy: understanding the application first, establishing realistic performance expectations and delivering measurement accuracy that is both achievable and verified under real operating conditions.
Planning a new installation or upgrading an existing system? Connect with CST to ensure your belt weighing solution performs reliably beyond day one.