Scale and detail of New Orleans Mint Coining Dept. - 1900 0

[RWB]

This table is a Fiscal Year summary of Coining Department operations at New Orleans for 1900 (July 1, 1899-June 30, 1900). Take particular notice of the multiple sources of "waste" gold recovery and the tiny actual loss of metal compared to the legal allowance. Operations at San Francisco and Philadelphia were much larger but all followed the same general metal recovery procedures.

Edited February 25, 2020 by RWB

[Just Bob]

I wish I understood the terms a little better. I assume "sweep" refers to the dust picked up off the floor and recycled, but to what does "grain" refer? And what are "clippings?"

It appears that the loss percentage reported is a typo. It should be .01194 percent. But, that may have been the proper way to write it at the time.

[physics-fan3.14]

The lost 3500 ounces? Where did it go? 

[RWB]

22 hours ago, Just Bob said:

I wish I understood the terms a little better. I assume "sweep" refers to the dust picked up off the floor and recycled, but to what does "grain" refer? And what are "clippings?"

It appears that the loss percentage reported is a typo. It should be .01194 percent. But, that may have been the proper way to write it at the time.

This might help better understand the document.

Terms:

Clipping – metal strip remaining after blanks are cut, also condemned blanks/planchets/coin.

Filing – metal filed off of blanks to reduce weight to standard.

Sweep – metal recovered from used crucibles, aprons, bags, gloves, tools, flux, etc. Ground to dust in  the Mint’s basement using a “Chili Grinder.”

Well Sweep – All wash water (including lavatory hand washing) was pumped to a well. This was cleaned annually and the metal recovered.

Grain – Particles recovered from under the floor grating, edge of crucibles, etc.

[See From Mine to Mint for details and photos of flooring and a grinder.]

 Central part of page under “Delivered in Settlement” can be confusing. Here is the translation:

Follow “Filing Bar No. 1” from left to right. The bar weight was 555.25 ounces, and it assayed at 893 fine. That gives a total pure gold weight of 495.83825 ounces pure – but the table shows “550.93” ounces….What’s wrong? This is the Coining Department and all gold and silver in the department is 900 fine, not 1.000 fine (pure). The numbers in the next to right column are in Standard Gold which is 900 fine.  To get the correct metal weight in Standard Gold we have to divide pure ounce weight by .900, which gives 550.931 ounces.

Per cent wastage is the percent of the legal allowance. The statement value of “11.94” percent is correct except for a rounding error on the last digit – the correct value is 11.95%.

Edited February 26, 2020 by RWB

[Conder101]

On 2/25/2020 at 4:21 PM, physics-fan3.14 said:

The lost 3500 ounces? Where did it go?

Probably up the flue as metal vaporized during melting.  From tim to time they would also disassemble the flues and chimneys to recover precious metals from the soot and and linings of the chimney's.  Sometimes they would also recover it from the roof of the building when it had condensed out of the smoke.

[Just Bob]

13 hours ago, RWB said:

 

Per cent wastage is the percent of the legal allowance. The statement value of “11.94” percent is correct except for a rounding error on the last digit – the correct value is 11.95%.

Got it. I was figuring it as a percentage of the total amount rather than the legal wastage amount.

[kbbpll]

On 2/25/2020 at 2:21 PM, physics-fan3.14 said:

The lost 3500 ounces? Where did it go? 

I too have trouble imagining 220 pounds of silver just going up the chimney. I suppose over the course of a year maybe it's possible, but still, almost a pound per work day. I know they kept close watch and anyone suspected of walking off with coin or metal was dealt with harshly, but seeing that, the temptation must have been enormous. The "wastage" was 5 years' pay for some of those guys.

[RWB]

Silver was more easily lost in refining and precipitation than gold. At New Orleans, a considerable quantity of silver came in as Mexican/Peruvian "cake" which was the compressed residue of mercury amalgamation (see the "patio process" in From Mine to Mint). Recovery was never complete since a little silver was carried off with residual mercury during melting and refining.

[RWB]

17 hours ago, Just Bob said:

Got it. I was figuring it as a percentage of the total amount rather than the legal wastage amount.

FYI - If any Mint officer/Department approached even 50% of the legal wastage, it was cause for a major, very intrusive investigation and suspicion of theft.

[numisport]

On 2/27/2020 at 5:12 PM, RWB said:

Silver was more easily lost in refining and precipitation than gold. At New Orleans, a considerable quantity of silver came in as Mexican/Peruvian "cake" which was the compressed residue of mercury amalgamation (see the "patio process" in From Mine to Mint). Recovery was never complete since a little silver was carried off with residual mercury during melting and refining.

Surprisingly a type of mercury amalgamate was used for dental fillings (I had a couple that are now crowns).

[Conder101]

On 2/27/2020 at 12:29 AM, kbbpll said:

I too have trouble imagining 220 pounds of silver just going up the chimney

It sounds like a lot, but that was out of almost 30 MILLION ounces, a loss of .01%