Claudia Vejrazka

Yes, we have custom tunnel profiles that we then apply to custom tunnel types. I think the issue might be that in the presets for the tunnel types it doesn't maintain the selected custom profile but reverts back to the first standard profile, which is 'square', which then seems to update the drives when saving and closing.

Hi guys, I have noticed in the last version (5.4.3.2) that I seem to have consistent issues with editing airways that exist in multiple stages. The most consistent error is that when I want to remove an airway from that stage that I am currently displaying by unticking the stage box in the edit window it does all kinds of crazy things. Sometimes it refuses to do it completely, sometimes it recreates the airway as unique to that stage but leaves the airway alone in other stages and sometimes it deletes the airway in all other stages and makes it unique to the current one. This sometimes also happens when modifying airways in stages that are not currently displayed, but not as consistent. I also had issues with updating airway cross-sectional profiles in staged models that it would revert back to what it was previously when saving the model and reopening it. I haven't been able to pinpoint what action would cause the model to revert back, after updating a number of times it eventually stuck, but it meant a lot of rework.

Thanks Martin.

sounds good. even if you have one of those tick boxes saying "do no show this message again" like you have with some others.

Hi guys, is there any way I can get rid of this notification when I copy data to the clipboard? It's ok when you have to confirm it only once or twice, but doing it constantly when transferring data from different points gets a bit old. Thanks.

Hi Adrian, For years we used 0.0018Ns2m-8, which was back calculated from the Lift 1 airblast. Later on, when one of our neighbours did actual measurements across two accesses into the cave their measured values were out by a magnitude. We figured out that the muckpile resistance has to be further normalised for the cross-sectional area of the undercut following the square law of mine ventilation based on the Chezy-Darcy relationship.The value we came up with was 0.0203 Ns2/m8 per m at 10,000 m2 undercut area, which is what the Ventsim simulations use. The measurement was probably at a similar general porosity as Lift 1, which was 25% at the time. I agree the actual resistance is locally dependent on varying porosity, so this is more of a global constant. But I always found with my simulations that your worst affected areas are not your footprints themselves, but the main accesses where the air from the whole footprint flows together. So while the model might not be very accurate on a drive by drive basis the error should be a lot smaller in your high velocity areas, same as the normal ventilation modelling really. You never get fantastic correlation in individual drives, but the in and out of the footprint usually work really well. You could also argue that the risk of airblast is the highest in the first years of caving operation, which would mean you would expect similar porosities (at least for porphyry type deposits). I did write a paper for Massmin 2016 about this as well. I can't remember if you did come to that. It's been a while. If you want to have more of a detailed chat, feel free to send me an email: claudia@resolvemining.com.au We really don't know enough about the fundamentals of airblast and have been trying for years to convince people to give me an ore pass that we can fill with different fragmentation rock and do PQ surveys on to get some better ideas, but it would involve significant costs. Hope that helps a bit.