Improving Kiln Efficiency and Copper Smelter Reliability Through Real Time Moisture Control
Copper | Open Pit Mine | Moisture Management
How a leading copper producer tapped into material intelligence to improve the efficiency of their kiln and smelter process
BACKGROUND
In copper smelting, moisture control is essential for maintaining safe, efficient and predictable kiln performance. Feed material entering the kiln must remain within a narrow moisture range. Excess moisture reduces thermal efficiency, increases residence time and restricts throughput, while material that is insufficiently dried after the kiln can cause handling issues, blockages and inconsistent downstream flow. At a major copper operation in North Queensland, operators required real time moisture visibility at both the kiln feed and discharge points, supported by additional upstream monitoring at the mine to stabilise moisture variability before material reached the smelter.
THE CHALLENGE
The smelting circuit faced persistent moisture variability driven by changes in ore source, underground humidity, seasonal weather and the natural presence of “wet face” and “dry face” domains within the mine. These fluctuations had a direct impact on kiln performance. When wetter material entered the kiln, drying cycles were extended and additional thermal energy was required. At this smelter, the typical process moisture for concentrate feed is around 7 to 8 percent, however pre kiln moisture was observed to rise to approximately 10.5 percent during periods of variability. This additional 2.5 percent moisture equates to roughly 30 kilograms of extra water per dry tonne of feed, requiring approximately 0.08 GJ per dry tonne of additional energy to evaporate. At normal feed rates, this translated to an extra 12–14 GJ of thermal energy per hour, representing an additional operating cost of approximately $50,000 to $100,000 per month. While the process could tolerate higher moisture, this excess drying demand consumed thermal capacity, reduced overall efficiency and increased fuel usage. Conversely, when material was insufficiently dried, operators experienced downstream handling issues and inconsistent product flow.
Without continuous measurement, smelter personnel relied on lagging laboratory results and visual assessments, limiting their ability to respond in real time and increasing the likelihood of reactive adjustments. The operation required a moisture monitoring system that could measure continuously, integrate with existing controls and deliver laboratory-equivalent accuracy across both the mine and smelter.
The MoistScan delivered up to $600,000–$1.2 million per year in avoided energy costs by reducing excess drying demand caused by elevated feed moisture.
THE SOLUTION
RTI deployed four MoistScan microwave moisture analysers across the copper operation. Two analysers were installed at the smelter, with one positioned before the kiln to measure incoming moisture and the second located on the discharge conveyor to confirm kiln drying performance. The remaining two units were installed at the mine, providing early insight into moisture variation across different underground moisture domains. This combination allowed the site to track moisture from the source through to the smelting process.
The calibration results demonstrated high accuracy and stability. One smelter unit achieved an RMSD of 0.3 percent after recalibration, confirming close alignment with laboratory results, while another improved from 1.73 percent to 0.6 percent, reinforcing the analyser’s performance across different moisture conditions. By integrating MoistScan data into the smelter’s control system, operators gained reliable real time visibility of moisture trends. This allowed kiln operators to regulate drying conditions proactively, respond to spikes in incoming moisture and verify that kiln discharge material consistently met target levels.
IMPLEMENTATION & DISCOVERY
RTI’s service team worked across both underground and surface operations to gather representative calibration samples. Underground analysers were calibrated using belt cuts and spot samples collected from a range of moisture zones. At the smelter, calibration involved targeted sampling and cross-checks against laboratory assays to ensure accuracy across the full operating range.
During implementation, operators discovered strong correlations between moisture spikes at the kiln feed and material sourced from wetter underground domains. Real time discharge monitoring also proved valuable for confirming drying performance before issues escalated. These insights enabled more stable kiln operation, fewer reactive adjustments and greater confidence in downstream material handling. Operators quickly adopted MoistScan data as a primary reference for decision-making due to its proven alignment with laboratory measurements.
THE RESULTS
The introduction of real time moisture analysis delivered measurable improvements across kiln performance, energy efficiency and material consistency.
Improved Kiln Efficiency: More stable feed moisture reduced thermal variability and improved overall drying efficiency within the kiln.
Predictable Drying Performance: Continuous monitoring of kiln discharge moisture allowed operators to confirm effective drying and respond quickly to deviations.
Reduced Energy Consumption: By limiting pre kiln moisture excursions from 10.5 percent back toward the target 7 to 8 percent range, the site avoided evaporating approximately 30 kg of excess water per dry tonne, reducing drying demand by 12–14 GJ of thermal energy per hour.
Lower Operating Costs: Reduced excess drying translated into an estimated $50,000 to $100,000 per month in avoided energy costs, based on typical industrial energy pricing.
Reduced Risk of Over or Under Drying: Real time moisture insight minimised downstream handling issues, improving material flow consistency.
High Accuracy: Calibration achieved strong alignment with laboratory samples, with RMSD values of 0.3 percent and 0.6 percent confirming reliable performance.
More Consistent Smelter Feed Quality: Early detection of moisture variation from underground moisture domains helped stabilise feed conditions entering the smelter.
By implementing RTI’s AllScan, the operation eliminated waste and took full control of ore quality.
INDUSTRY IMPLICATIONS & FUTURE APPLICATIONS
This project demonstrates how continuous moisture analysis can improve smelter stability, drying consistency and overall process predictability across copper operations.
Kiln feed optimisation using real time visibility to stabilise drying requirements.
Automated drying control by integrating MoistScan data into burner and airflow regulation.
Underground moisture domain monitoring to reduce variability before material reaches the surface.
Processing plant integration to maintain consistent moisture levels during crushing, screening and conveying.
CONCLUSION
By implementing MoistScan technology across both the mine and smelter, this copper operation achieved precise, real time moisture control at every critical stage of production. The improved accuracy and responsiveness delivered stable kiln performance, reduced energy demand and more consistent downstream material flow. With MoistScan providing reliable moisture insight from underground operations through to final drying, the site strengthened operational reliability and improved process efficiency, supported by Real Time Insights & Operational Certainty.