Improving Kiln Feed Chemistry and Overburden Wasting through Controlled Consistent Quarry Material Mix: A Case Study at Union Bridge Cement Plant

Cement is made by milling clinker with a mix of grinded gypsum. The clinker is produced using a rotary kiln which burns a mixture of limestone, clay, magnesium, silica, and iron with desired atomic percentages. The quarry is the primary source of raw material for the rotary kiln in cement production. The consistency of material feed chemistry, in which the quarry plays a key role, is crucial for optimizing the performance of a rotary kiln. The quarry implemented a six-step methodology that comprised a modified 3D mining software modeling tool, a database computer loop prediction tools, and other tools to improve mining sequencing, optimize raw material usage, and provide consistent chemistry mix material for the kiln. By using overburden as a raw material in the mix, the quarry nearly universally reduces the environmental impact of squandering unwanted material in the quarry. This has a significant environmental impact since it requires less space to manage the overburden waste generated during mining. In addition, raw material usage was optimized for clinker production causing a reduction of 4% in sand usage as raw material, reduction in raw material purchase cost, reducing the variability of kiln feed chemistry, and producing high-quality clinker. The standard deviation of kiln feed LSF was improved by 45 percent, and the variability in kiln feed was reduced by 65 percent.