Icmj trip Monday

[Goldwasher]

Hangtown and I made the trip to Iowa Hill Monday. Cool spot never been there nice drive. I skipped going to Auburn first and we misjudged the caravan timing so we missed it and showed up when they were meeting in the parking area. The Prez. of the Gold Hounds GAVE a 3 dwt nugget to the fella who had traveled the farthest...he got a semi teasing BOO HISS...he was from RUSSIA! They separated everyone by detector brand Steve H. was there I wanted to try and say hi and shake is hand but, I never ran into him. They pretty much opened up the whole claim to people so they could see what they could get. And told people where they could/should scrape and had some piles and water sources for guys to hi-bank if they wanted. They had just scraped new bedrock and gravel. I asked if we had our own gear where to set up. One of the guys took me over past where the fresh bedrock was and showed me a spot that had been showing color.Basically at the head of the old diggings on bedrock at the face of the old washed wall. I'm sure this is the area Gravelwasher got his piece the other day. We could have chose to work a pile they provided but, the chance to dig at the bottom of the pit in virgin ground in a more separated area was hard to pass up. We were right next to the area where a lady, it may have been "Dee" that Ray Mills wrote about in this months journal( it looked like her at least) was pulling pieces out of the cemented gravel on bedrock. Not sure how many but, she got a few. There was an old drift tunnel right by us and we were cleaning bedrock and getting into some very old cemented gravel too. I walked around to the other hi-bankers no one was really boasting about there finds, the people scraping and panning weren't showing to much either. There were a few noticeable detector finds heard a hoot every once in a while I don't think anyone found any lunkers. John scraped broke and dug and I fed the mean green machine. No chance to sample really so we just looked for a good area near found gold. We ended up with a good pile of cleaned gravel and a little bit of color...give me a week in that pit and it would be a different story Kudos to the owner for letting a bunch of derelicts run amuck on his claim....

 

[Oakview2]

Color me jealous

 

[Aufisher]

Nicely done gentleman! Pretty fascinating geology and mining history!

 

[Lotus Geologist]

Pretty much the same experience as us on Friday (even gave a 3pwt nugget to a woman from Germany!)... Ran about 50-60 buckets of virgin cemented gravel that I dug myself through the high banker... Back breaking load of work! Did a couple quick checks of the mats and a sample pan of the concentrates and I doubt we got more than a gram. I still have to do a thorough clean up so I could be wrong. I've been getting more than that out of 5-6 pans when crevacing on the SFA.

Gonna hit a new section of river by kayak on Friday!

L.G.

 

[Lotus Geologist]

One comment... I was VERY surprised at the very VERY small amount of black sand caught in the box... I was so baffled that I ran some test pans with the same results... Hardly any black sands! I was getting my gravel from right off the top of the slate bedrock... Wondering if maybe the iron oxides had basically all oxidized away... That might account for the very high degree of cementation of these auriferous Tertiary gravels.

What do you think Goldwasher? Paging Clay Diggins too!

L.G.

 

[Campngolf]

Good lookin' pan. Caravan schmaravan. You showed up when it counted.

 

[Hangtowndiggins]

Awesome event, great experience, good people and gold! Thanks again Goldwasher, It was a excellent day to remember
Goldwasher feeding the hog and our nice little pile of washed rock
I dug exposed and cleaned this bedrock, also dug a good little hole down against the face into cemented tertiary gravels and we got a little gold. Ran my GBpro around where I dug and tailings after but no luck

 

[Goldwasher]

The most fines were coming from blonde/yellow sands really really fine. Light sands you are supposed to avoid due to their supposed lack of color. I was actually thinking today about that and if you sampled the pit and found " more" black sand would you find" more" gold. Now I have a geologist askin' me questions....... The deposit is what? 13 million years old at least? If there is black sand and it oxidizes and turns to Ma' Nature brand cement does the sand lose color and weight? The cobble and cement that John was breaking into and giving me to run was purple, burgundy and peacockish...it seemed like we were starting to increase our quartz level. The cons had a significant amount of white sand hanging out with the black sands that were there and the fly poop. There was a lot of mica in the cemented matrix...huge teaser as when it is behind moving water it kind of loses its sparkly property and glows more like gold. Every so often I would reach into the hopper and grab a glowing piece. The cement was full of it. I saw the owner a few times , I was hoping he would come our way so I could ask a few questions. No real idea about the channels direction and its local characteristics. On our claim there is very little black sand and zero tertiary or inter-volcanic deposits. On Weber creek in Placerville and out in Grizzly Flat we got a ridiculous amount of black sand..and mercury. On the American too. and the Consumnes. Any time I have dug material with ancient gravel influence I get varied gold. Monday we got gold that had red on it and some that was so yellow it may almost be electrum. The interesting thing to me is when I look at that wall I don't see eons of deposits I see a few seasons at most....what do you think lotus?

 

[Hangtowndiggins]

 

[Goldwasher]

Hangtown did all the hard work. I just threw some stuff in every few seconds and played in the spray!!!

 

[Lotus Geologist]

I agree about the history of that exposd wall of gravels... Those remaining gravels appears to be large event beds... Flood deposits in the ancient river beds that for many reasons were never scoured away to be later replaced with younger gravels.

I think the cemented matrix contains more gold than what we extracted with the high banker... We definately had balls of cemented sands and pebbles make it all the way through the system. I am soaking a couple buckets of pay dirt and will try crushing the cemented sands today and see what I get. This material was sampled directly on top of bedrock, still cemented in place.

In the absence of black sand, there was a notable patina of Fe/Mg oxides on the quartz pebbles and cobbles... I imagine the same is on some of the gold.

Will report back after I mess with the material I brought out a bit more.

L.G.

 

[Hangtowndiggins]

Hangtown did all the hard work. I just threw some stuff in every few seconds and played in the spray!!!

Well hey at least you can blame my digging for the take being a bit on the skimp side lol... See what happens when you leave the pick and shovel work to me?..

 

[Aufisher]

Crush and quench time!

 

[bug]

Those ancient antediluvian type, white quartz channels, generally have very little black magnetite sand. The iron in them seems to have come from sulfides and not the lode stone magnetite. Just my observations..

 

[Clay Diggins]

One comment... I was VERY surprised at the very VERY small amount of black sand caught in the box... I was so baffled that I ran some test pans with the same results... Hardly any black sands! I was getting my gravel from right off the top of the slate bedrock... Wondering if maybe the iron oxides had basically all oxidized away... That might account for the very high degree of cementation of these auriferous Tertiary gravels.

What do you think Goldwasher? Paging Clay Diggins too!

L.G.

Just a couple of thoughts Lotus.

First off the gold was not found throughout the Tertiary channels. These were river beds and just like river beds today the gold was deposited in pockets and streaks. Add in a few dozen million years of compression, heating, twisting and shearing and where you find the heaviest pockets is anyone's guess. The bottom could very well have ended up on the side or the top. Gold is truly where you find it. Most of those gravels should not be expected to have pockets of gold.

If the black sands did contain significant Fe and it had decomposed it would be seen as limonite, staining the cement in yellows and oranges. It can't be repeated enough here that black sands are often found associated with gold in alluvial deposits but black sands are not an indicator of gold itself. Every wash in the desert southwest has black sand but few have gold.

The fact that gold and black sands are often found together is the same reason garnets or sapphires are sometimes found with gold - specific gravity. When mineral materials have an opportunity to physically sort themselves the "heavies" find their way to the lowest levels. It doesn't matter that there were no black minerals when that happens, gold will still find it's way to the bottom of the sorted heap. Remember you are prospecting for gold, don't get caught up in expecting the same heavies as other places you have prospected.

You say the gravel was "cemented". Do you mean that the area between the cobbles was as tough and dense as cement? That's what I would expect from unmined Tertiary river gravels in the Iowa hill area. That stuff is really tough and without power tools, or at least two guys working a star drill I wouldn't expect to dig and process 50 buckets in a full day.

Here is what I would expect to see as "cemented" gravels in that area. Anything less and I would have to say you were working tailings that had re-consolidated themselves by mechanical and chemical action. Photo, and find, courtesy of Digger Bob.

 

[Lotus Geologist]

Some of the cemented gravels indeed looked like that (albeit without the visible gold)... and were a pain to bust up with the sledge and breaker bar... to get the fifty buckts we did cheat and run some of the over burden, plus some material from a pile that the owner believes was stockpiled by the last claim owner and never run.

L.G.