New Zealand Gold Prospecting & Metal Detecting Forums Archive

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Ben		Posted : Monday, 30 April 2012 1:55:12 PM(UTC)
Rank: Gold Dust Groups: Registered Joined: 3/03/2012(UTC) Posts: 3 Location: Auckland Thanks: 4 times		Me and my mate are pretty new to fossicking. Been having heaps of fun but havent found any gold yet. We made a little 1 meter by 100mm sluice. The riffels are right angels , shaped like a upside down L ,30mm high with the top lip about 30mm. They are at 70mm spacings. We are a bit worried they are to high (just chopped them down from 50mm) and may be just washing any gold over the top. There is allways a reasonable amount of the black sand(magnite?) and quartz left over in the carpet and behind the riffels. Theres just a good chance theres just no gold where we are looking. Weve found a few pieces of some silvery metallic substances so Im guessing it might be working allright.Ill put a few pictures up of of the metallics when i figure out how to. Basically just wondering if the riffels are to big. Weve been powering the water through about 30-50mm above the riffel height. Is this to much water flow for the gold to drop down behind the riffels.Ill try attach a video of the sluice working. Thank you for any of your help, very grateful for any tips

LepreSean		Posted : Monday, 30 April 2012 2:39:53 PM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 8/12/2011(UTC) Posts: 171 Location: Wherever I may roam Thanks: 187 times Was thanked: 130 time(s) in 78 post(s)		Hello Ben sounds like you are on the right track, make sure the gravel gets a chance to run over some exposed carpet or miner moss etc, ideally the riffles take up no more than the bottom third of your box. I see most sluice box's these days the riffles take up the whole box, but I think the carpet helps to slow and catch the fines. It is a bit of trial and error trying to figure out the riffles, but try having them a little closer together with the 'L' on a slight angle, this design is known as 'Hungarian riffles', http://www.mygoldpanning.com/sluiceboxes101.html
		auri sacra fames (accursed hunger for gold)

oroplata		Posted : Monday, 30 April 2012 2:50:31 PM(UTC)
Rank: Gold Ingot Groups: Registered, Moderators Joined: 16/06/2011(UTC) Posts: 1,040 Location: Christchurch Thanks: 23 times Was thanked: 211 time(s) in 152 post(s)		Bring some gravel/ironsands home next time you go, then buy some alluvial gold off trademe (or someone here) and mix it into the gravel. Then set up a test rig and run your mix through it and see what % of the gold you recover. You can do it as many times as you want until you know what water rate/sluice angle gives you the best results. It's what those idjuts on "gold rush" should have done with their first claim. :)
		WWW

overdog		Posted : Monday, 30 April 2012 6:26:19 PM(UTC)
Rank: Gold Ingot Medals: Groups: Registered Joined: 2/03/2010(UTC) Posts: 418 Location: nelson Thanks: 69 times Was thanked: 82 time(s) in 68 post(s)		what Oroplata said. Btw does that idiot on Gold Rush sleep in his hard hat cos he never takes the thing off...

Cleggie		Posted : Monday, 30 April 2012 6:33:20 PM(UTC)
Rank: Gold Nugget Groups: Registered Joined: 24/03/2012(UTC) Posts: 88 Location: Christchurch Thanks: 88 times Was thanked: 59 time(s) in 31 post(s)		Hi Ben, I have been through exactly the same problem and here is my take on it (for better or worse). I think the riffles are too high, I was running my sluice with 20mm high riffles and found the the sluice was glogging up with small stones and gravel and the water flow was unable to clear the riffles. The material behind the riffles should be in a state of agitation and the water flow should carry away all the small stones and light material leaving just the heavies, black sand and gold. http://www.youtube.com/w...bl2w&feature=g-all-u http://www.youtube.com/w...ature=endscreen&NR=1 Here are a couple of videos that may help you understand how riffles work and help you in riffle design for your sluice box. I don't suggest you go out and buy the GoldHog matting as it is expensive. I brought some ribbed rubber matting from Para rubber and glued some 8mm high rubber riffles at 40mm spacings and was impressed with the improvement to the sluice opperation. Cheap and effective. It is important that your gold catching matting come in contact with as much of the slurry you run through your sluice as possible. If your matting becomes glogged up then you are losing gold. Hope that helps.

Ben		Posted : Monday, 30 April 2012 9:26:13 PM(UTC)
Rank: Gold Dust Groups: Registered Joined: 3/03/2012(UTC) Posts: 3 Location: Auckland Thanks: 4 times		Originally Posted by: oroplata Bring some gravel/ironsands home next time you go, then buy some alluvial gold off trademe (or someone here) and mix it into the gravel. Then set up a test rig and run your mix through it and see what % of the gold you recover. You can do it as many times as you want until you know what water rate/sluice angle gives you the best results. It's what those idjuts on "gold rush" should have done with their first claim. :) Thank you for tip. Id be keen to buy some alluvial gold and give it a go if I could buy some from you or anyone else if there out there.

Ben		Posted : Monday, 30 April 2012 9:29:26 PM(UTC)
Rank: Gold Dust Groups: Registered Joined: 3/03/2012(UTC) Posts: 3 Location: Auckland Thanks: 4 times		Originally Posted by: Cleggie Hi Ben, I have been through exactly the same problem and here is my take on it (for better or worse). I think the riffles are too high, I was running my sluice with 20mm high riffles and found the the sluice was glogging up with small stones and gravel and the water flow was unable to clear the riffles. The material behind the riffles should be in a state of agitation and the water flow should carry away all the small stones and light material leaving just the heavies, black sand and gold. http://www.youtube.com/w...bl2w&feature=g-all-u http://www.youtube.com/w...ature=endscreen&NR=1 Here are a couple of videos that may help you understand how riffles work and help you in riffle design for your sluice box. I don't suggest you go out and buy the GoldHog matting as it is expensive. I brought some ribbed rubber matting from Para rubber and glued some 8mm high rubber riffles at 40mm spacings and was impressed with the improvement to the sluice opperation. Cheap and effective. It is important that your gold catching matting come in contact with as much of the slurry you run through your sluice as possible. If your matting becomes glogged up then you are losing gold. Hope that helps. Thank you heaps for you advice,very much appreciated

LepreSean		Posted : Tuesday, 1 May 2012 2:01:43 PM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 8/12/2011(UTC) Posts: 171 Location: Wherever I may roam Thanks: 187 times Was thanked: 130 time(s) in 78 post(s)		If you cant find any Au to use try some lead, scrape off small to large size slivers and use these as an indication of the effectiveness of your set up. Edited by user Tuesday, 1 May 2012 2:40:06 PM(UTC) \| Reason: Not specified
		auri sacra fames (accursed hunger for gold)

Ben		Posted : Tuesday, 1 May 2012 9:20:55 PM(UTC)
Rank: Gold Dust Groups: Registered Joined: 3/03/2012(UTC) Posts: 3 Location: Auckland Thanks: 4 times		Originally Posted by: LepreSean If you cant find any Au to use try some lead, scrape off small to large size slivers and use these as an indication of the effectiveness of your set up. Might have to be the lead option, sounds like a good idea thanks

rob		Posted : Sunday, 24 June 2012 10:24:36 PM(UTC)
Rank: Gold Flake Groups: Registered Joined: 8/09/2011(UTC) Posts: 11 Location: Dunedin Thanks: 8 times Was thanked: 2 time(s) in 2 post(s)		Good info on the lead Sean, Lead shotty pellets are really good as they give a good test - the thin flat pieces of lead will let you know how good the settling rate (therefore the flow) of the box is. Rob

Juggie		Posted : Monday, 25 June 2012 9:56:40 AM(UTC)
Rank: Gold Nugget Groups: Registered Joined: 4/11/2010(UTC) Posts: 32 Location: Wellington Was thanked: 14 time(s) in 9 post(s)		Cheap lead is easy enough to get ... fishing sinkers from Kmart or the Warehouse. Try slivers off a bigger one & some of those "Split Shot" for rounder bits ... try cutting some of the split shots in 1/2 to get "D" shaped pieces. What you don't use can be put into your fishing equipment :)