Bedrock and Gold: The mysteries . . .

[Lanny in AB]

Do you love to chase the gold? Please join me--lots of gold hunting tips, stories of finds (successful and not), and prospecting poetry.

Nugget in the bedrock tip:

I had a visit with a mining buddy this past weekend, and he told me of an epic battle to get a nugget out of the bedrock, and of what he learned from the experience. I thought some of you might like to learn from his mistake.

While out detecting one day, he came across a large sheet of bare bedrock. The bedrock was exposed because the area had been blasted off with a water cannon (a monitor), by the old-timers! It was not fractured bedrock, in fact it was totally smooth.

He was not optimistic at all of the prospects of a nugget. But, for some reason (we've all been there) he decided to swing his detector over that bedrock. After a long time, just as he was about to give up on his crazy hunch, he got a signal, right out of that smooth bedrock.

There was no crevice, no sign of a crevice, nada! So, he had to go all the way back to camp to get a small sledge and a chisel. The signal in the rock intrigued him, but he still wasn't overly optimistic. For those of you that have chased signals in a similar situation, sometimes there's a patch of hot mineralization in the bedrock that sounds off, but this spot, according to him, was sharp and clear right in the middle of the signal, not just a general increase of the threshold like you get when you pass over a hot spot in the bedrock.

Anyway, he made it back to the spot and started to chisel his way into the bedrock. If any of you have tried this, it's an awful job, and you usually wind up with cut knuckles--at the least! Regardless, he kept fighting his way down, busting out chunks of bedrock. He kept checking the hole, and the signal remained very strong.

This only puzzled him all the more as he could clearly see that it was solid bedrock with no sign of any crevice. He finally quit at the end of the day, at a depth of about a foot, but still, nothing in the hole.

An experienced nugget shooting friend dropped by the next morning to see him, and asked him how the hunt was going. My buddy related his tale of the mysterious hole in the bedrock, and told the friend to go over and check it out, and see if he could solve the riddle.

Later in the day, the other nugget hunter returned. In his hand was a fine, fat, sassy nugget. It weighed in at about an ounce and a quarter! After my friend returned his eyeballs to their sockets and zapped his heart to start it again, he asked where the nugget had come from.

Imagine his surprise when he heard it came from the mystery hole!! He asked how deep the other guy had gone into the bedrock to get it. "Well, no deeper" was his reply.

So, here's the rest of the story as to what happened. When the successful nugget hunter got to the bedrock, he scanned the surface got the same strong signal as my buddy. He widened out the hole and scanned again. Still a solid tone. He widened the hole some more so he could get his coil in, and here's the key and the lesson in this story, he got a strong signal off the side of the hole, about six inches down, but set back another inch into the side of the bedrock!!

My unlucky friend, the true discoverer of the gorgeous nugget's resting place had gone deep past the signal while digging his hole!!

Now, of course, a good pinpointer would easily solve this problem. The problem was, my buddy didn't have one, so why would he widen the hole, right? Well, the other guy was the one with more experience, and that's why he did. It was a lot more work, but what a payoff!

So, my buddy's butt is still black and blue from where he kicked himself for the next week or so for having lost such an incredible prize.

Some nugget hunting lessons are harder than others to learn. . . .

All the best,

Lanny


P.S. When in gold country--check the bedrock, regardless of whether it looks likely or not! Mother Nature likes to play games sometimes.

 

[OwenT]

I now see you replied to my thread already. I'll take a look. Thanks!

 

[Lanny in AB]

Owen, hope you had some luck.

This past summer was stinking hot! I went out detecting and it was mostly a zero on the fun scale because of the heat. I did find some gold, but I also dug a ton of trash and lots of bullet lead--anyone that hunts for nuggets knows how tiring digging lead can be as it always sounds sweet like gold.

I spent some time detecting in the Nevada desert in early November and found a lot of the same material as mentioned above around some old gold mines, always interesting to see what the Old-Timers left behind in the way of trash.

The nice thing about Nevada in the fall is that the weather is nice and mild compared to the summertime heat up here in the northern wilds.

All the best,

Lanny

 

[Lanny in AB]

I can't overemphasize how important it is to check exposed bedrock with a metal detector when in known nugget country. The Old-timers did not get all of the gold from previously worked bedrock, whether mined by hand or hydraulically worked.
As gold is heavy, it loves to work its way down into any crack or crevice (I've watched this in real-time while dredging, and disturbed gold reacting to stream flow does a sluggish slide along the bedrock until it hits an opening, and then it disappears right quick!).
As the Old-timers had no electronics to sniff out gold, they missed nuggets--this can't be overemphasized. Over and over again with my detectors, I've captured nuggets from old goldfields that were extensively hand-mined. Moreover, I've detected lots of recently mined bedrock (done with large equipment), and nuggets are constantly being missed, so many in fact that if a lot of nuggets are detected on worked bedrock, the miners will go back and tear up the bedrock again to get the gold until the detectors can't sniff any more out.
Nuggets that are lying relatively flat are quite easy to hear, but the ones that are edge up, they're trouble because of the tiny surface presented to the coil.
Go low and slow on bedrock, really scrub that coil and listen sharply for any variation in the threshold. A lot of nuggets first present that way (not a lot of scream out), they signal only as a disturbance in the threshold. Repeat your coil sweep, hit it again from 90 degrees, turn up your sensitivity if allowable, and make another pass.
To verify a target, scrape, dig, chisel down until either the signal disappears, or the target pops out. (A good thing to remember while using a VLF is that they're designed to find metal, so I've dug and chiseled only to find types of native iron or oxides? *A PI machine is better at ignoring some of the previously mentioned signals.*)
Note: Ironstone will throw off the target ID of gold nuggets, so you really need to work until you expose the target just to be sure. Lots of nuggets don't first present as gold on the ID, sometimes not until you're right on top of them. And, if there's a sizeable chunk of ironstone under/beside/on top of a nugget, your ID will still be off, so dig until you eyeball it.
When detecting bedrock, I always use a one-two punch approach. I hit it first with a high-quality dedicated gold circuit VLF until the bedrock goes quiet, then I hit it again with a high-quality PI. It's amazing what a VLF leaves behind in warm to hot bedrock that a PI will sniff out, plus the PI punches far deeper than the VLF, and many sassy nuggets can't hide from that!

Happy hunting, and all the best,

Lanny

 

[delnorter]

Always a pleasure Lanny.
Mike

 

[Lanny in AB]

Hey Mike, thanks for the note, and it's always great to hear from you.

All the best,
Lanny

 

[Lanny in AB]

High-banker piles or screened dry dirt piles in gold mining country.

About fifteen years ago, I was out in the desert in Arizona with a mining buddy of mine. He was highly experienced in getting that sassy desert gold.
So, as a favor, he took me to a spot where the old-timers had done a ton of dry-washing and it hadn't been beat to death.
There were piles all along the rim of a big gulch, good gold ground or all that work wouldn't have been done.
He told me to walk along the rim and detect the piles, as they were great spots for recovering nuggets that slid off the screens. After a while of finding lots of trash, I headed downslope and then off to an adjacent gulch.
Not long after, he gave me a shout and told me to come back up to the rim. He pointed at a dry-washer pile only a few yards away from where I'd quit, and in his hand he had a beautiful multi-gram desert nugget he'd pulled from the tailings pile.
I could have and should have kicked myself for being so dumb as to wander off after such a great tip to detect where he wanted me to work.
Lesson learned. . . .
Last summer, I found a spot where lots of old-timers had worked around huge boulders where a gigantic glacial dam had burst upstream and spun the gold in behind the big rocks.
There was one giant boulder that had a fresh throw-out pile where someone had dug a hole about six feet deep on one side of the rock. They'd classified the dirt dry to take the screened material to the creek for panning, about half a mile away.
Remembering my spectacular failure of long ago in the desert, I knew I needed to check that throw-out pile. Boom! Two sweeps of the Goldmonster and a big screaming signal. The target had to huge from its sound.
But when I recovered it, there sure was a lot of surface area, but it was one of the flattest nuggets I've ever found, more like a thinly rolled Cornflake. (Is there such a thing as a flake-nugget?)

Nevertheless, that lesson from years ago had me check the pile and recover the gold.

All the best,

Lanny

 

[Lanny in AB]

As a follow-up to my previous post, I'm assuming everyone knows that a boulder on bedrock in prime gold territory works as an amazing gold trap.
While gold dredging, I've watched flakes of gold disturbed while working the gravels off the downstream base of a boulder scoot quickly back under the boulder.
As well, the gold, flakes and nuggets, it's not just found off the downstream base, it's back under the boulder as far as it can travel. And, if there's any cracks or crevices, they can be a real bonanza. Also, depending on variations of stream flow (direction changes during flooding, etc.), there can be pockets of pay on the sides, with gold deposited on the upstream base of the boulder as well. However, it's been my experience that the best pay is on the downstream side and locked underneath there too.
As for boulders dropped from a huge glacial outwash (from a glacial dam bursting) there are some similarities, but some differences too. By finding the general direction the outwash travelled, that's a tell as to where the gold pockets will be, on which side of the boulder. Unlike a regular stream deposit that might leave the gold under, around and deposited on the sides, a dam burst usually leaves the gold on one side only, with any nuggets under that side as well, with scant or no gold, anywhere else.
Just a few thoughts and observations from chasing the gold that I'd like to pass on.

All the best,

Lanny

 

[Chilli]

As a follow-up to my previous post, I'm assuming everyone knows that a boulder on bedrock in prime gold territory works as an amazing gold trap.
While gold dredging, I've watched flakes of gold disturbed while working the gravels off the downstream base of a boulder scoot quickly back under the boulder.
As well, the gold, flakes and nuggets, it's not just found off the downstream base, it's back under the boulder as far as it can travel. And, if there's any cracks or crevices, they can be a real bonanza. Also, depending on variations of stream flow (direction changes during flooding, etc.), there can be pockets of pay on the sides, with gold deposited on the upstream base of the boulder as well. However, it's been my experience that the best pay is on the downstream side and locked underneath there too.
As for boulders dropped from a huge glacial outwash (from a glacial dam bursting) there are some similarities, but some differences too. By finding the general direction the outwash travelled, that's a tell as to where the gold pockets will be, on which side of the boulder. Unlike a regular stream deposit that might leave the gold under, around and deposited on the sides, a dam burst usually leaves the gold on one side only, with any nuggets under that side as well, with scant or no gold, anywhere else.
Just a few thoughts and observations from chasing the gold that I'd like to pass on.

All the best,

Lanny

You are a wealth of gold wisdom Lanny. 👍

 

[Lanny in AB]

A bit more on big boulders and massive chunks of broken bedrock from glacial dam bursts.

There's an area where I've done a bunch of detecting that is a giant debris-field of carnage, surface chaos leftover from a huge glacial dam burst eons ago. The boulders vary in size from bread-loaf to small/medium car size, and the pieces of bedrock from hand-size to garage size, no joke! This debris field carries on for miles, so the force of that ancient event boggles the mind.

With all that force on the loose, any gold was either scooped up or gouged up from where it was resting in ancient gravels, or on or in the bedrock. And any gold travelling with large pieces of rock in such a dam burst outwash would naturally drop when the rock did. (Not only that, in early reports from the area, gold was even found resting on flat areas of huge chunks of bedrock!)

I knew a guy that used heavy-duty hydraulic jacks to push the boulders apart and sometimes was able to push or tip them over so he could detect the exposed virgin gravels underneath, and he did very well.

When heavy items of any size drop from the carrying force of a hydraulic flow, the accompanying gold drops as well, something important to remember when you're out chasing that sassy gold.

All the best,

Lanny