The effectiveness of a milling circuit incorporating a pebble crusher depends on instantaneous performance, run-time, and the consistency with which the required rate and product size are delivered. This paper examines the challenges associated with each of these factors in pebble crushing circuits. In addition to the usual application guidelines for effective crusher operation and performance, pebble crushing is subject to specific conditions which, if unaddressed, can significantly detract from both crusher performance and the effectiveness of the overall milling circuit. Consideration is given not only to the ability to achieve instantaneous process performance targets but also to the need to ensure mechanical reliability. To fully explore and understand these issues, the paper combines the authors’ extensive operational experience with a mechanistic cone crusher model to illustrate and quantify their causes and remedies. Specific aspects examined include trickle feed, choke feed, mass distribution, particle size segregation, and feed size distributions encountered in pebble crusher duties. Beyond instantaneous performance and reliability, many system effectiveness issues stem from time-based variability, including the wear condition of mill discharge grates, pebble ports, and pebble crusher liners. Steady-state snapshots can describe conditions at points during the various cycles, but they do not adequately define the impact of the transition from one operating state to another. Importantly, such transitions are a major cause of performance interruption and therefore productivity loss. The paper investigates the main issues arising from interactions between autogenous and semiautogenous grinding (AG/SAG) mills and pebble crushers, concentrating on the circuit dynamics. A suite of traditional steady-state and advanced dynamic process simulations is used to identify why projected performance is not always realised. The analysis considers feed presentation, operational capabilities, and the substantial variation in process performance that can result from operational strategies at the crusher and across the wider circuit. The steady-state operation assumed in most flow sheet simulations is rarely observed in pebble crushing circuits. Dynamic simulations are used to investigate and quantify the resulting effects on circuit performance, mill stability, and throughput, and to show how these effects can influence the choices made in the design and specification stages of a project. Operational, design and capital options to realise the full throughput uplift potential of a pebble crushing–mill circuit are described and quantified. The paper also discusses how the identified issues and proposed solutions can be applied to milling circuits, together with the implications for more novel options such as high-pressure grinding rolls (HPGR) in pebble crushing duties.