Try this program - looks good, gonna try this meself asap - seems great inhouse!
set disc to zero
tone 1 202 khz
tone 2 0-28 358 khz
tone3 28-end 733 khz
audio resp 4
GB set manually to 2 or 3 above average or run in tracking but this gets a little chattery if GB tracks into 70's
Just listen for clear two way high tones. Some of them might be a little mixed with a bit of low tone overlap but if they are spitty or broken and reading either low numbers or 98 it will be iron. Notching out 98-99 seems to clean up the wanted non-ferrous signals and notching out 0-6 makes the programme a lot quiter as without this you are obviously hearing a lot of low/mid tone iron signals because the audio cannot be set below 200khz and this really needs to go lower so you can hear the iron grunts instead
Hi Neal, I unfortunately can not sign up (cause I'm not British) but I'd like to ask your permission for a good photo. I'dI like to have a stab at getting this into the New Scientist either as a reply to an article, such the recent "Waste not..." march 3, 2012 pg 5 ... or to just to get the visibility as a serious environmental issue that needs to be immediately acted upon. I'd return the article to you, and you can put your name and links to it if you like, just before I send it in.