dave wiseman said:
One would think that most of the good gold would be in the quartz cobbles and boulders from the oversize material....
Yes.....& of course.....oversize nuggets too, that just skiped on down & through the rotating trommel screen & out the back of the dredge along with all the waste tailings to end up on the tailings pile.
Hi Guys, Very intereting.. This detecting of these old, in New Zealand, bucket dredge tailings piles, is something I too have ponded over for a while. I think NZ was the birth place of these MONSTERS, in later years, that ravaged the river banks & the alluvial flats. As long as they had water to float in, there was no stopping these rattling, clunking, shreking, moaning & groaning powerfull piles of steel & metal. Only when the gold ran out or there pond of water drained away & broke there backs. The farmers & pastoliasts & public grew to hate them. To the farmer & pastolist they just destroyed the best flat & furtile land leaving in there wake a moon scape of piles of rock & rubble that was only good for breeding rabbits, possums, gorse, broom & briar.
Over time many of these piles have been bulldozed flat & turned back into good useable pasture, at a cost of course. But some have been left in historic reserves so we can be reminded of what they were like. Even as I tap these keys a modern day plant is processing ground besides one such reserve. Whether it is re processing old tailings or just carrying on where the old bucket derdges stopped, I arent sure.
Here is a link to a photo & more informtion about this historic tailings plie reserve for those of you interested enough to have a look.
http://www.centralotagonz.com/Earnscleugh-Dredge-Tailings
I like the idea of hitting these tailings with my biggest coil, a nugget finder 25" mono. Might not be the easiest to swing as the tailings I am sure are going to be difficult ground to clamber about on. Maybe the 24 x 12 elliptical will be better suited. Time will tell. But I think you do have to go for depth as any gold is either going to be big nuggets that went through with the tailing or as Dave said, going to be in with the quartz rocks & boulders. Being heavy it would have sunk in to the piles a bit over the years I am sure, so is going to be down a bit. There isnt going to be any bed rock so I think it is just going to be a metter of getting in there & getting stuck in to it. Maybe starting at the top & working down & around. I am picking there wont be any sort of patten & just randemly scattered & dumped. There may be "patches" where bed rock may have been dredged up with a pocket or crevice of bigger gold that went through the plant & dumped. Here is hoping. I am bound not to be the first to do this, I know I arent, but I will let you know how I do. I am looking at doing this in the new year.
Happy hunting & good luck out there.
JW