slurry pooling Valery and powell

Slurry pooling, excessive accumulation of slurry in the mill, and the associated loss of throughput and grind, are well-recognized on low-speed, single-stage SAG mills. However, it is becoming apparent that a wide range of high-throughput mills also suffers from pooling issues due to factors such as the treatment of less competent ores and excessive pebble porting. This paper presents data from various mills operating in different applications to substantiate the claim that mill throughput is predominantly controlled by discharge capacity. A deeper understanding of these dynamics is critical for enabling higher mill throughput. The study evaluates superficial discharge flow velocities in two SAG mills with differing open area percentages to analyze the effects on slurry discharge restrictions. Testing indicated that modifying discharge parameters can yield a significant throughput increase. Specifically, simulations based on a reference SAG mill model suggested that adjustments in pulp lifter depth and trunnion discharge area could potentially enhance throughput by approximately 20%. Therefore, it is imperative to address these transport limitations to optimize mill performance in high throughput contexts.