Development, reconciliation and visualisation of hang-up frequency and fines entry forecasts at PT Freeport Indonesia

Abstract

Fragmentation production and associated hang-up frequency and fines entry forecasts have been incorporated into the existing PCBC-based production forecasting workflow at PT Freeport Indonesia. These forecasts inform numerous operational aspects including draw scheduling, production planning, cave shape targeting and wet muck hazard management. This paper first describes two key aspects of the workflow that have enabled forecasting of these quantities at the drawpoint-month level for the life-of-mine: 1) block models of expected primary and secondary fragmentation, derived from block models of point load index, cave back stress potential and volumetric vein/fracture intensity measures of vein point load index and 2) an empirical relation between hang-up frequency, draw rate and rock block size and strength, derived from reconciliation of forecast versus measured hang-up frequency at GBC and DMLZ. This is followed by an overview of the forecast outputs and the reconciliation process, which is central to calibration of the methodology and the production of a reliable forecast. This process relies on rapid, accessible and up-to-date visualisation of the forecast and actual data in the form of time-based heat maps and charts, which are also used to communicate the forecast outputs to all stakeholders.