The grade control bottleneck | Tom Guy, Continuous Improvement Manager, OceanaGold Macraes

Grade control samples took 48+ hours under fire assay. That meant dig blocks held up and excavators walking to another area while they waited. Tom Guy, Continuous Improvement Manager at OceanaGold's Macraes mine, on the grade control bottleneck and what changed when PhotonAssay™ went in: same-day turnaround, exploration results in four days instead of months, and enough flexibility that the mining team stopped planning around delays. Tom also covers what the team got wrong about measuring the improvement and the one thing he'd tell other sites to prepare for. Read the full Macraes case study: https://www.photonassay.com/resources... Chapters 0:00 Intro 0:52 Production delays from fire assay 1:32 Evaluating PhotonAssay™ 2:17 Implementing PhotonAssay™ 3:53 Keeping operations moving 5:00 Quantifying the improvements 5:36 Managing the transition 6:28 A change for the industry Definitions CRM - Certified Reference Material  LPG - Liquefied Petroleum Gas  QC team - Quality Control team  RC rig - Reverse Circulation drill rig  HQ / NQ core - Drill core diameters; HQ is the larger, NQ the smaller.  Variability - How much results differ from each other  Representative sample - A sample that represents the larger source material it was taken from  Stopes - The underground voids left after ore is extracted  Headings - Underground tunnels driven forward to access ore  Bench turnover - Completing mining of the current pit level  Cut-off grade - The minimum gold grade at which rock is worth processing as ore  Grab samples - Spot samples taken by hand underground  Upside model - A scenario modelling a larger, longer-life mine  Re-fires - Repeating a fire assay when the first result fails quality checks Tails grade - The small amount of gold left in residue after processing  Dig blocks - Defined volumes of ore released for excavators to mine  Grade control patterns - The planned grid of samples taken to map ore and waste before digging  Core holes - Diamond drill holes producing solid cylindrical core  Ore block - A defined volume of rock classified as ore rather than waste  Mine-to-mill reconciliation - Comparing the grade predicted by the model against what the mill actually recovered  Resource model - The estimate of how much gold is in the ground, reported to market  Aliquot - The portion of the sample actually analysed; 500g with PhotonAssay™ versus 30g with fire assay   Nameplate limit - The machine's rated maximum throughput  Grade control - Sampling during mining to decide what's ore and what's waste  Ore body - The body of mineralised rock being mined