and Bond BMWi were measured daily over a twelve-month period. The time-series trend and parity plot both demonstrate a strong correlation between measured mill throughput and model predictions. The JKDWT and SMC Test® form part of a broader methodology rather than serving as simple ore characterisation tests. In addition to correlating with blast fragmentation and SAG mill throughput, ore-specific parameters obtained from these tests are applied in the specific comminution energy benchmarking methodology (Morrell, 2008) and in mathematical models used within the JKSimMet software to predict AG/SAG mill and crusher performance for plant design and optimisation purposes. 1.3 SAG Mill Design During the design of a SABC circuit, SAG and ball mill dimensions and installed power are selected to ensure the circuit can accommodate the expected ore competency while achieving the target grind size and nameplate capacity. Ore competency is characterized by two key attributes: (a) resistance to impact breakage—or competency in AG/SAG milling—as measured by the JKDWT or SMC Test®, and (b) grindability to achieve the final product size in a ball milling circuit—or competency in ball milling—as measured by the Bond Ball Mill Work Index (BMWi). A comprehensive ore characterisation campaign is therefore essential to capture the variability of ore competency for both SAG and ball milling across the deposit. For mill design purposes, representative ore characteristics are commonly taken as the most competent 80th percentile values of both Axb and Bond BMWi (David, 2013). Figure 40 presents the Comminution Footprint, showing Axb values and corresponding Bond BMWi for 261 ore samples from a deposit spanning the life of mine. While a broad trend exists between the two parameters, they are not expected to be strongly correlated, as they represent different breakage attributes of the same ore measured on different size ranges using distinct tests. The 80th percentile ore competency for this Figure 39 – Actual Mill Throughput vs Model Predicted Mill Throughput
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