Novo: CEO Rob Humphryson on Mechanical Sorting
“Hi Erik
Apologies for tardiness in replying to the 2nd round of Q&A (received on 21.08.2020) – combination of either being too damned busy or it being inappropriate to comment on some of the questions outside official news release channels for legal reasons. Many of your original questions have been answered in subsequent news release so hopefully those who asked the questions now have their answers.
Thanks for your follow up questions to answer some queries that have come up to you directly or via ceo.ca about the recent sorting release.
The productive capacity of the sorters is important, but its’ not just about the tonnes, it’s a combination of things. Mainly it’s about the % of tonnes per size fraction, the productivity per size fraction and the recovery per size fraction. The news release talks qualitatively about the recovery per size fraction – ‘encouraged by getting halo gold recovered’ and particularly getting as much gold as we did in the -8mm that was never tested at Tomra (where the bottom size fraction used was -6mm). Read the releases referenced in the most recent release and you’ll see the story building to what we see now, precisely as predicted with some prophetic words in the news releases 2 years ago. I think we got the balance right in being patient and allowing the sorter manufacturers time to fully understand what it was they were trying to solve for and let technology catch up as it inevitable would (and has). The recent Steinert tests were not about grade – they were about setting the trial up for success. The cost and time involved to determine a grade was cost and time not well spent given what we already know.
The sorter on order can do well above 300tph. We wanted one that could hit the currently known top of the range of sorting productivities, with feed and discharge capabilities to suit so that we can attempt to measure the top end productivity of each size fraction.
The dirt at comet well seems to fit roughly into thirds :
25-75mm 30%
8-25mm 40%
-8mm 30%
This will change with blasting (maybe weighted towards producing finer fraction) and gentler crushing (weighted towards producing coarser fraction), plus the larger scale digging. Se we won’t know the split of each size fraction until we do a decent scale test. This does not really cause us to lose sleep though.
Productivity ranges (very rough)
25-75mm 80 – 350tph
8-25mm 40 – 120 tph
-8mm 15 – 50 tph – but this is based upon typical experience with typical sorter usage and doesn’t account for our unique nugget / halo situation – could yet be very conservative. We may be able to speed it up by screening out the ‘very fine’ material (say -2mm) and bypass the sorters and so long as we don’t trip any truck tonnage limits it can hitch a ride to Nullagine within the airgaps of the coarser concentrates if it has enough gold in it – and it may well do).
Recovery per size fraction is the key and now we know that we can detect and eject very fine gold across the size fractions and notably in the -8mm size fraction, this gives us great confidence for the work planned in the field in 2021. Often when scaling field trials up there is a loss in performance but we see nothing in this technology that would cause gold loss when scaled up from laboratory testing. The sorters have the processing power to scan up to 4000 objects per second and use up to 185 different parameters on each rock simultaneously and using nested ‘if / then’ functions, pinpoint the targets for ejection. A plausible outcome is that with more material on the belt we may see a dirtier concentrate with more overshoot (material with no gold reporting to concentrate as collateral damage from the air ejections), which we won’t mind so long as we get the lion’s share of the gold. Looking down the track a bit, this is not really a problem and can be easily rectified by running the concentrate through a subsequent sorter to clean it up to reduce the trucking volume if required. The final array of sorters is one of the key outcomes of the trials, so not much point second guessing the outcome, suffice to say that with a simple processing solution of crushing / screening / sorting (no chemicals, no water, no tailings dam, no 3 year approval and construction period), I cannot conceive of anything that would remotely approximate the capital costs of a traditional processing facility. Then throw in the very rapid set up time, the mobility and flexibility of the units, high uptime characteristics, the long life nature of the assets and the low operating costs and it starts to get very interesting. Not sure yet about how the sorters will perform during the wet season and whether or not that could place some sort of seasonal restriction on the operation, but if it does cause issues I think they are manageable – it’s not like we’d have very expensive capital sitting idle (mining fleet excepted) and not like the workforce wouldn’t mind some time off around Christmas / New Year ……. The time could also be used for any maintenance requirements or walking the sorters closer to the centroid of next season’s mining to reduce mine trucking time.
Really important in the recent trials was the involvement of Jason Aleknavicius in a hands on sorting operation role, plus the involvement of two more of our geological exploration team that operate around the West Pilbara. It’s really important for internal understanding and enthusiasm that as many people are positively engaged at the trial status (and I personally ran daily trips down to the testing for office staff so they can get a better understanding whilst the testing is close to home) so that there is not just one project champion. Everyone at Novo knows full well what this can do for us now that we have a processing facility at Nullagine and we can’t wait to get started. Jason is extremely busy maintaining oversight of the IGR 3000 at Egina (his first 3 months with Novo were involved with actually running the plant as one of three crews on a 2 week on 1 week off roster) and he’s also overseeing the re-start of the laboratory at the Golden Eagle Processing Plant at Nullagine, including considering if and how Minanalytical’s Chrysos technology might integrate into the process, plus of course investigating in detail how we will treat the sorter concentrate from the Karratha Project. His work schedule should ramp down in time for the sorting trials after the wet season to allow him to take a hands on role as chief ‘sorter tinkerer’.
The Novo team are very excited about the trials and we think we’re as well prepped as we can be. There’s some drilling planned just prior to the trials – we’ll leave it until then to ensure the information we gain is fresh in everyone’s minds, plus we still need departmental approval (which is much easier to get if the local Aboriginal group has approved the works) and we need to finalise details around treatment of the concentrate at Nullagine.
Hope this helps.
Regards
Rob Humphryson
Chief Executive Officer
Novo Resources Corp”
