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View Full Version : OT: gold again being mined at Sutter's Creek, California



tlfamm
12-18-2012, 12:41 PM
http://news.yahoo.com/stream-molten-gold-signals-return-large-scale-underground-051010931.html

" ...
The last of the state's great mines closed because mining gold proved unprofitable after World War II. But with the price of the metal near historic highs, hovering around $1,700 an ounce (28 grams), the California Mother Lode's first large-scale hard rock gold mining operation in a half-century is coming back to life.

Miners are digging again where their forebears once unearthed riches from eight historic mines that honeycomb Sutter Gold Mining Co.'s holdings about 50 miles (80 kilometres) southeast of Sacramento. Last week, mill superintendent Paul Skinner poured the first thin stream of glowing molten gold into a mould."

sasquatch
12-18-2012, 04:37 PM
Interesting.

Northern Ontario is now in a GOLD Boom. Think there are at least 7 mines reopening.
My son is a mechanic at a Huge mine operation that will be in production in Jan./13.
The road into this place is 100 miles long through the bush, and there are 1600 employees there, 1200 building the operation to get it running, and another 400 on site working for contractors that are maintaining the equipment etc.
Employees are in for 14 days straight , (12 hour days,) then back out for 7 days.
A geat place for young guys to go to make some BIG $$$.

Black Forest
12-18-2012, 05:41 PM
He lived here but I don't know if he was born here.

darryl
12-18-2012, 07:26 PM
I hear that you can cast a titanium brick, then cover it with gold and pass it off as a gold bar. As long as the gold never gets used for anything, who would know? :)

Lew Hartswick
12-18-2012, 07:34 PM
I hear that you can cast a titanium brick, then cover it with gold and pass it off as a gold bar. As long as the gold never gets used for anything, who would know? :)
Not if anyone has scale to weigh it. Ti is very much lighter than Au.
...lew...

Machine
12-18-2012, 07:42 PM
I hear that you can cast a titanium brick, then cover it with gold and pass it off as a gold bar. As long as the gold never gets used for anything, who would know? :)

Not titanium (which is very light) - tungsten is what's used.

Machine
12-18-2012, 07:46 PM
Here's a coupla links...

http://www.runtogold.com/2010/03/fake-tungsten-gold-found/

http://3.bp.blogspot.com/-xdAxmbE4fC0/UFyK7sz9SwI/AAAAAAAAJ1A/aaw1rjWM6Xk/s1600/Fake+gold+bar+tungsten.jpg

http://www.nogw.com/images/tungsten-filled-gold-bar.jpg

Lew Hartswick
12-18-2012, 07:47 PM
Not titanium (which is very light) - tungsten is what's used.
That has a bit better chance: W spg. 19.3; Au spg 18.88 It would take a
decent scale and volume measure to tell that. :-)
...lew...

Duffy
12-18-2012, 07:55 PM
Just to be clear, gold is weighed in TROY onces, about 31 grams. Avourdupois(sp?) ounces of everyday commerce equal about 28 grams. At $1700/oz the difference DOES matter!:o

Machine
12-18-2012, 08:05 PM
That has a bit better chance: W spg. 19.3; Au spg 18.88 It would take a
decent scale and volume measure to tell that. :-)
...lew...

Density of gold at room temp = 19.30 gm/cm^3 Density of Tungsten at room temp = 19.25 gm/cm^3

Pretty darned close, that's why it's used.

Black_Moons
12-18-2012, 08:52 PM
I got a better scam.
Apparently you can take mild steel, cover it in gold and pass it off as a drill bit!
http://images.toolstop.co.uk/product/IRW10502585.JPG

Black_Moons
12-18-2012, 08:55 PM
Density of gold at room temp = 19.30 gm/cm^3 Density of Tungsten at room temp = 19.25 gm/cm^3

Pretty darned close, that's why it's used.

I think you got those two swaped?
http://www.engineeringtoolbox.com/metal-alloys-densities-d_50.html says
Gold 19320
Tungsten 19600

And if tungsten is more dense, then an alloy (or just discreat globs) with lighter metal could be used to produce the exact same density as gold.

Grind Hard
12-18-2012, 08:55 PM
I got a better scam.
Apparently you can take mild steel, cover it in gold and pass it off as a drill bit!
http://images.toolstop.co.uk/product/IRW10502585.JPG


My money, TAKE IT. I must have this shiny marvel!

darryl
12-18-2012, 09:22 PM
Sorry, I meant to say tungsten, not titanium. And the gold drill bits- yeah I've been caught in that scam! Had a heck of a time scraping that gold off the fake hss. :)

Tungsten being heavier than gold by a tad- you would just drill out some of the tu, then fill it with aluminum or steel before plating on the gold.

I don't know what truth there may be to that rumor about faking the bars with tungsten, but it certainly could work. Can you imagine the repercussions if a major stash of 'gold' was found to be faked- can you say s--- hits the fan!

Of course there would be some means of discerning this by checking the resonant frequency of the bars. I would imagine that tungsten would have a higher tensile strength than gold, so it should be possible to 'ring' the bars and thus determine a fake.

Duffy
12-18-2012, 11:52 PM
The idea of a gold plated tungsten brick has a certain appeal. However, how are you actually going to do it?
You certainly cant melt and pour it into a mold like a gold ingot. Trying to sinter powdered tungsten into an ingot will probably produce a lower density product than as-cast. Anyway, what kind of sintering press would it take? Buying tungsten block and machining it into an ingot-shaped object would probably be the best bet. Now lets figure out exactly how to gold plate it.
Nobody is going to go to this trouble for ONE ingot! And then there is the problem of a buyer. We have a little business here in Ottawa that sells gold ingots-it is called the Royal Canadian Mint. It buys raw gold, mostly from mining companies, and re-refines it to "five nines" purity. They dont get much walk-in trade!:)

Machine
12-19-2012, 12:39 AM
I think you got those two swaped?
http://www.engineeringtoolbox.com/metal-alloys-densities-d_50.html says
Gold 19320
Tungsten 19600

And if tungsten is more dense, then an alloy (or just discreat globs) with lighter metal could be used to produce the exact same density as gold.

I don't have them swapped. The source you refer to doesn't specify the temperature that a tungsten density of 19600 kg/m^3 applies to. Density varies with temperature due to thermal expansion and contraction. According to wikipedia, the density of tungsten at near room temperature = 19.25 g/cm^3. Room temp of gold is = 19.30 gm/cm^3.

Machine
12-19-2012, 12:47 AM
The idea of a gold plated tungsten brick has a certain appeal. However, how are you actually going to do it?
You certainly cant melt and pour it into a mold like a gold ingot. Trying to sinter powdered tungsten into an ingot will probably produce a lower density product than as-cast. Anyway, what kind of sintering press would it take? Buying tungsten block and machining it into an ingot-shaped object would probably be the best bet. Now lets figure out exactly how to gold plate it.
Nobody is going to go to this trouble for ONE ingot! And then there is the problem of a buyer. We have a little business here in Ottawa that sells gold ingots-it is called the Royal Canadian Mint. It buys raw gold, mostly from mining companies, and re-refines it to "five nines" purity. They dont get much walk-in trade!:)

A tungsten core, armor piercing 20mm-30mm cannon slug wrapped in a gold covering would make a dandy anti-tank weapon. Denser than depleted uranium, with a super hard penetrator core and a soft malleable outer shroud to smoothly go through rifling in a barrel. Mount it in an attack airplane and call it the Au-10. ;)

Optics Curmudgeon
12-19-2012, 01:07 AM
Armor piercing shells made for large caliber seacoast guns had a hard steel core with a soft steel "cap" that served as a sort of lubricant to ease its passage through the target's armor.

SteveF
12-19-2012, 07:54 AM
Armor piercing shells made for large caliber seacoast guns had a hard steel core with a soft steel "cap" that served as a sort of lubricant to ease its passage through the target's armor.

Not really a lubricant, more of a shock absorber to lessen the impact and chance that the hard steel core would shatter.

Steve

Lew Hartswick
12-19-2012, 09:17 AM
I don't have them swapped. The source you refer to doesn't specify the temperature that a tungsten density of 19600 kg/m^3 applies to. Density varies with temperature due to thermal expansion and contraction. According to wikipedia, the density of tungsten at near room temperature = 19.25 g/cm^3. Room temp of gold is = 19.30 gm/cm^3.

I think both of you guys had better look in REAL source for things like this.
" Would you employ a butcher to do surgery?"
The CRC "Handbook of Chemistry and Physics" ( the "bible" for this sort of information)
Has the following: Gold Au sp. gr. 18.88 at 20 deg C
Tungsten W sp. gr. 19.3 at 20 deg C
As far as I'm concerned that is the numbers to take to the bank.
...lew...

Machine
12-19-2012, 09:49 AM
I think both of you guys had better look in REAL source for things like this.
" Would you employ a butcher to do surgery?"
The CRC "Handbook of Chemistry and Physics" ( the "bible" for this sort of information)
Has the following: Gold Au sp. gr. 18.88 at 20 deg C
Tungsten W sp. gr. 19.3 at 20 deg C
As far as I'm concerned that is the numbers to take to the bank.
...lew...

I agree there seems to be a bit of "variety" out there for these densities. I checked in several sources though, seems like the consensus is around the numbers I provided. The National Institute of Standards and Technology (NIST) government website sets the density of Gold at 19.32 g/cm^3 and Tungsten at 19.3 g/cm^3, although they don't provide temperatures. I would assume whatever temperature they're using is at least consistently applicable.

http://physics.nist.gov/cgi-bin/Star/compos.pl?mode=text&matno=074

http://physics.nist.gov/cgi-bin/Star/compos.pl?matno=079

Barrington
12-19-2012, 10:09 AM
The CRC "Handbook of Chemistry and Physics" ( the "bible" for this sort of information)
Has the following: Gold Au sp. gr. 18.88 at 20 deg C
Tungsten W sp. gr. 19.3 at 20 deg C

:confused: From the CRC "Handbook of Chemistry and Physics" (88th edition):-

Gold (Sanskrit Jval; Anglo-Saxon gold), Au (L. aurum, gold);
at. wt. 196.966569(4); at. no. 79; m.p. 1064.18C; b.p. 2856C;
sp. gr. ~19.3 (20C); valence 1 or 3.

Tungsten (Swedish, tung sten, heavy stone); also known as wol-
fram (from wolframite, said to be named from wolf rahm or
spumi lupi, because the ore interfered with the smelting of tin
and was supposed to devour the tin), W; at. wt. 183.84(1); at.
no. 74; m.p. 3422C; b.p. 5555C; sp. gr. 19.3 (20C); valence 2,
3, 4, 5, or 6.

????

Cheers

.

Lew Hartswick
12-19-2012, 11:11 AM
By gosh they may have changed it. But it does have an ~ in your edition. Mine is quite a bit older but doesn't have a ~ in it. I wonder what is going on here???
...lew...

Barrington
12-19-2012, 12:20 PM
An interesting point which may explain why there's no definitive answer (from later in the same source):-

"The specific gravity of gold has been found to vary considerably depending on temperature, how the metal is precipitated, and cold-worked."

Cheers

.