Nugget anomaly ?

[Mgumby16]

This weekend I was out with some friends dredging a section of stream with 2 4" prolines between two old gold mine adits from the 1850.

During our first cleanout my friends 4" has an 18.5 grain nugget sitting right on top. But the rest of the cons had nothing even as big as a 1 grain piece and this includes the other dredge. And for the rest of the weekend all we recovered was very fine gold.

Generally in my experience when you find a nugget it's is generally accompanied by more good chunky gold. But this one wasn't and it's has us a bit baffled. Any thoughts?

Here is some more info it is a small creek maybe only 15 feet from bank to bank and less then 1 ft of water. The historical records say that 1 ounce nuggets were pulled from the stream gravels up stream a short distance from the mine in the 1850s.

 

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[triple d]

I would head up stream and try to find the source. Testing along the way. If there one there is likely more.

 

[BurntBear]

It's possible that the section you were dredging has been dredged before. Any indications?

 

[bug]

Creek gold also tends to be real spotty.

 

[Mgumby16]

TripleD - we plan on eventually sampling our way upstream. And we have already found that there are multiple sources on the creek because I sampled a stretch about 1/2 mile down stream from were we were and the gold was very crystalline almost looked like lode gold.

BurntBear - It was not dredged in the past. It's on private property and I have permission from the owner and he hasn't let anyone else in there. Also it's a 1/2 to 3/4 mile trip to it from the road. Last time that I can find that it was prospected was in the 1890's at which point a 14 pennyweight nugget was found.

Another thing of note is that all the deep areas in the creek have no overburden just exposed bedrock. So I think when this creek floods it seems to blowout the deep areas for some reason.

 

[BurntBear]

Good!

From your description, it sounds like there may be a quick drop in elevation. That's usually where I see areas with no overburden.

 

[KiddoTheMiner]

Creek gold also tends to be real spotty.

i know plenty of productive creeks, i find rivers less productive

 

[Mgumby16]

A lower portion of this creek has been very productive. Pulled 7 grams in 2 short days. With 8 very crystalline 3 to 4 grain nuggets. This section is very close to another source that is separate from the source near the mines.

 

[KevinInColorado]

i know plenty of productive creeks, i find rivers less productive

This is soooo true here in metro Denver too. Around here, some little creeks produce 5-10x the gold of the larger waterways (which were ALL dredged back 100 years or more ago). The creeks are stunningly spotty too as others have mentioned. In one spot recently, I pulled 0.21 grams in an hour and a half or less. Dug another hole 6-8 feet away and got 0.03 grams in a similar amount of time.

Sooo get yourselves up that creek to find the hot spots!

 

[triple d]

Those deep areas. With bedrock if theres cracks the gold could be. Hiding in those cracks if you can reach them. Low pressure area and bedrock a good combo.

 

[BurntBear]

Yup, I think I'd snipe that area.

 

[IMPDLN]

How well are you cleaning out the cracks and crevices in the bedrock? Gold can sink surprisingly deep into seemingly skinny cracks. Blaster nozzles can help get deeper into those cracks, but sometimes you have to scratch and claw into that bedrock to release those chunky pieces. And or maybe that particular section just doesn't have the coarser gold because most of it dropped out above that particular spot. There are no rules and that is why you have to keep sampling as you go. Dennis

 

[Mgumby16]

I was breaking bedrock with the blaster as well as rock hammers and crow bars. Breaking into the bed rock did not seem to increase the amount of gold. There is also a hard pack layer over the bedrock. I need to do more testing to see if the gold is coming from on top of the hard pack or on top of bed rock. The bedrock in this stream almost perfectly resembles the riffles in a sluice box.

I have a lot more testing and sampling ahead of me as I have access to almost 3 miles of this creek as well as a larger river that it runs into.

There's just never enough time. Haha

 

[BurntBear]

It's all a matter of finding where it's trapped now and potentially finding the source!

 

[bedrock bubba]

If it were me, I would go downstream until the creek started to drop its load and level out, and look for the first good gravel deposit. You had said the holes were blown out where you started, so whatever gold left over would be downstream.

The nugget you found was probably a lucky residual nugget that got trapped somehow in a crack. The source could have easily been cleaned out by now, as indicated by no flakes or fines left. This sounds like a worked out lode to me.

Got a topo map of the area, or pics? And what is the base rock, and what intrusives show?

 

[Lanny in AB]

Mgumby,

The responses to your questions come from some pretty solid people, and they sure are packed with a lot of good advice! I've enjoyed reading them.

It's sometimes powerful strange how and where gold gets deposited. I watched a show once where a guy panned a nugget when he was doing some heli-prospecting. He then went back with all kinds of equipment, very expensive indeed, and that nugget was all he ever found!

That's the way it goes sometimes, loner nuggets. It's happened to me before too, and it drives you nuts when you don't find any of their buddies.

All the best,

Lanny

 

[Mgumby16]

Thanks for all the responses! We got out for a day about 1/2 mile below the nugget anomaly spot and above the spot where I pulled 7 grams in two days.

Had good results 3 two to four grain pickers and a little over a gram and half total for about 6 hours of dredging. It's the best creek I've been on yet even with its anomalies.

Bedrock bubba the bedrock is a green chloritic slate with abundant quartz stringers and veins. It takes forever to clean it due to its incredible unevenness, it resembles the rifles in a sluice box but with great irregularities. You can go one way a foot and a crack will open up and drop down 2 feet. There are to many cracks in it to count and I haven't been able to really break into it because there isn't enough flow and we are recircing water.

I have maps but don't want to post them due to it being private property.

Thanks guys!

 

[Reed Lukens]

The nuggets and fines are usually coming from different sources. Whatever side of the creek the nugget was on, search up the hill with a detector to find out if the source is close.