Ann: Appendix 4E and 2017/18 Year Statutory Accounts, page-23

It is sustainable to a degree. If you consistently mine more than is treated in the mill you can use the highest grades from ore. That means mill head grade will always be higher than mined grade with a rising stockpile of lower grade material. Now is dry season, so Troy is able to mine more material now compared to last quarter enhancing the effect. Last quarter was somewhat bad mining-wise but saved by the stockpile.