Ancient Cement

[nickinCA]

I was up near the middle fork of the american river looking for old tertiary gravels a couple weeks ago and i came across some large pieces of cement loaded with river gravels. I also found some tailings from the drift mines that have been filled in and compared the tailings with the cement they were both loaded with small round quartz pebbles. I have heard about the old miners finding cement with gold in the ancient riverbeds. I did not actually bring back some of the cement to test but i did find some gold in the tailings. Anybody else have expierence with finding old cemented gravels?

 

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[kuger]

All of the Tertiary (SP?)gravels are cemented,miles and miles of them in Calif,gold can be found in any level too!(quartz in them doesnt really mean jack either,it would be uncommon to not find quartz in it)

 

[nickinCA]

thanks kugar but i have found gravels that aren't cemented and these were pretty much just like concrete blocks, but i think the miners dug them out and were going to process them in a mill or something. They looked just like concrete but similar to the uncemented gravels nearby.

 

[kuger]

In Situ they are all cemented(some more than others)when exposed to air it "air slacks",and crumbles,thats what made drift mining the most dangerous mining there is and was....many a mans bone buried in those coyote holes!It sounds like it would be worth while to break those open,and bench test them.Good luck!!

 

[nickinCA]

Interesting thanks. sure wish i took a piece home to crush it

 

[bug]

Heres a pic I took inside a cemented channel. Hand stacked rocks are holding up a section of collapsed roof. This mine was high above the american river also. Very little quartz in the cement flow but was a very rich mine in its day.

 

[mrs.oroblanco]

Dangerous stuff, for sure - Caliche.

Its the exact reason we had to participate in digging out a poor man on his honeymoon. California desert, old mine, lots of rocks stacked on the sides - couple hundred foot adit. He was afraid to go in, so he stayed near the mouth of the adit. He was buried standing up, literally, after he did a little hammering through the caliche (cemented gravels). His new wife (and new widow) came running, screaming incoherently (she forgot they had a 4 x 4), and it is something I never want to do again.


BE CAREFUL IN THOSE FIRST FEW FEET! Not worth the price he paid.Try to save your sampling for when there has been NO precipitation - it dissolves that stuff, but you cannot tell until a wall of cemented dirt falls after your second pick in a small spot. Also, do not do it alone - make sure you have a buddy with you. (outside the tunnel) Every year, in California, at least one or two people are either killed or hurt badly from that stuff.

B