Q. David Bowers
Refining Silver
After the assay the bullion passes to the refinery if it should require the operations there performed. It is melted in the refinery and poured out on water. There is a great sputtering for a few moments, and then a result called "the granulations" is perceptible. The solid molten mass has become scattered in particles of many sizes and indescribable shapes. The general appearance is that of the fallen leaves of forest trees which have become crisped up by the frost.
The granulations are then weighed and put into large cauldrons of ironstone china about the size of a barrel. The cauldrons are valued at $100 each, and the men working about them are very careful in their movements lest they should damage or destroy one. The cauldrons are set in rows on a false floor, under which pass steam pipes. Water flows around them to the height of about a foot. A quantity of muriatic acid is then placed in the cauldrons proportionate to the amount of granulations. They are then closed in or surrounded by a tight box or house. Steam is admitted to pipes beneath the false floor, and the steam heats the cauldrons and their contents. The red fumes at the chimney tops are generated in this process. This heating reduces the granulations to a fluid state if they are silver, but gold remains solid in granulations if part gold and part silver. The fluid is drawn off by a siphon and deposited in tanks about 12 feet in diameter which contain a stirring apparatus driven by steam power.
Common salt is then placed in the solution to precipitate the silver. It is deposited as chloride of silver, and the liquid is drawn off through filters and allowed to flow away. The chloride of silver precipitate is about the consistency of a mason's putty coat, and resembles it very closely in other re-spects. The acids are then cleansed out by washings in what is well known as the sweetening process.
Ingots and Strips
When the silver has been obtained in a state as near as possible to absolute purity it is taken to the press room, and by hydraulic pressure compressed into solid circular masses of from 12 to 15 inches in diameter and five inches thick, re-sembling very much the shape of a cheese. The silver is then placed in an oven in iron pans. A fire is raised and the iron and oven are brought to a cherry red color for the purpose only of driving off moisture in the chloride of silver. The least portion of moisture in the crucibles would break them, and the silver would be lost in the ashes. The cakes next go to the melter and are run into bricks. If it goes on the market as bullion, its weight in ounces and its value is stamped upon each brick. If it is to be turned into coin, it is again melted and an alloy of one-tenth copper is put in both for silver and gold, and the whole is then run into ingots.
These are heated and rolled to the proper thickness and width, and the strips are then annealed and whitened. The blanks are next punched and cleansed of the grease from the rollers, and are then sent to the adjusters. Each piece is weighed and if found too heavy a little is filed off the edge; if under weight, it is remelted.
Milling and Striking
From the adjusters the blanks pass to the stamping room. The milling, as it is generally termed, is then put on, but not at all according to the popular idea. If the blacksmith's homely but expressive word of "upsetting" were used instead of milling, there would be but little doubt as to the process.
After it is upset, to raise the ring on the surface, the blank passes under the die. The impression is made on both sides from one blow. The milling is in reality by pressure-squeezing the silver out into the little grooves of the mold. A rule of the coiner's department does not allow an employee to leave it duringthe day until after the accounts are adjusted. From the coiner the money passes to the counter, who with the aid of a counting board, which holds an exact number of pieces, is able to count thousands where a person ordinarily would count only units. The counting board carries just 1,000 silver dollars.
One of the most interesting objects to be seen in the mint is a large balance scale, so nicely adjusted that one may take a hair from the head, split it and place it on one of the scale pans, and the beam will be noticeably deflected.
Only dollars and "twenties" are now being coined, but there is money enough on hand in the mint to make half the town rich. There is more money than can be handled. The reporter noticed the heavy doors for a new vault which is to constructed as a strong place for the excess of coinage. There is $15 million in one vault, $8 million in another, and $6 million in another, besides bullion which will be turned into money as soon as the new vault is completed.