September 05, 1897: “THE ELECTRO-CHEMICAL PROCESS – Before closing this article the writer would call attention to the valuable improvements in machinery and processes for treating all kinds of ore made by L. E. Porter of Los Angeles, which processes are now controlled by the Porter Gold and Silver Extraction company of Los Angeles, a corporation recently organized and having an office at No. 1, 132 South Broadway. The Porter processes embrace amalgamation, lixiviation and electrolysis, and all the various chemical elements depending in each case on the character of the ore to be treated. By these proceses lixiviation, precipitation and filtration may occur in one and the same receptacle; but, of course, this would not be the case with every character of ore. All charging and discharging are done by gravity, and slimes are treated very cheaply, rapidly, and always effectually, by the Porter centrifugal filter.”—The Herald
July 1, 1898: “THERE ARE NOW six mills at Garlock. Mr. Henry, of the Henry mill, expects to put in a cyanide process.
Mr. L. E. Porter, of the Porter Gold and Silver Extraction Co., representing Los Angeles capitalists, is also putting in one of their improved cyanide plants.” – Mining and Metallurgical Journal
September 1, 1898; “THE LEWELLYN IRON WORKS AND L. E. PORTER, both of Los Angeles, are putting up a large cyanide process at Garlock to work tailings. It is estimated there are 10,000 tons of tailings there at the different mills, and probably $100,000 will be taken out of them. The capacity of the works will be equal to 60 tons per day.” — Mining and Metallurgical Journal
September 15, 1898: “L. E. PORTER & CO’S., new cyanide process plant, at Garlock, Kern County, will commence operations on 1st of September. The cost of the plant is $7,000, with a capacity of 60 tons daily.
They have 12,000 tons of tailings now waiting to be worked. It is the intention to maintain an assaying, cyanide and metallurgical department. The force employed at present will be 10 men.” — — Mining and Metallurgical Journal
September 23, 1898: “THE NEW CYANIDE PROCESS PLANT lately erected at Garlock, Kern County by Messrs. Porter & Co. of Los Angeles. Is now fairly at work. This plant has a capacity of 60 tons of tailings a day, and there are in the neighborhood of Garlock about twelve thousand tons of tailings to be worked. There are at present ten men employed.” – Los Angeles Daily Times
March 1899: “THIS MILL OWNED BY L. E. PORTER COMPANY was located in the town of Garlock. It had a capacity of sixty tons per day, and was built in the latter part of last year. The first work done by it was on ten thousand ton of tailings bought from the Henry, Garlock, and Pioneer Mills and the Yellow Aster Company, who had a large quantity of tailings at the mills where they formerly had their milling done. They have done some, and intend to do, custom work, as a great deal of the ore near Garlock is base, the mill will likely have all the work it can do, as its location will be the nearest point fore ores from Argus, Slate, and Panamint districts. The company consists of L. E. Porter, John Llewellyn of Los Angeles and H. Curtis of Boston. Mr. Porter is manager of the company and spends most of his time at the mill. He is the inventor of the Porter process, which has many advantages over the old ordinary style cyanide plants. A few of the leading points in its favor are given below:
First, cheapness of plant and economy of operation. The price of plants of various capacities are much cheaper than the ordinary cyanide process. The cost of operating a Porter plant includes chemicals, power for generating electricity, labor, wear and tear and interest on investment, and will ordinarily not exceed one dollar for each ton or ore treated, and sometimes will not be one-third of that amount.
Second, simplicity. No roasting or ores is required. Electricity, in combination with chemical solutions in the Porter Electro-Amalgamating Rotating Barrel,are all the conditions necessary after the ore is pulverized to the proper degree of fineness. The barrel revolves until the pulp, water and chemicals are thoroughly mixed and the entire contents fully charged with the electrical current, and sufficient time given for the precious metals to become precipitated or amalgamated on the plates prepared for that purpose, the usual being six hours. The process is as simple as ordinary amalgamation.
Third, high percentage of extraction. That is extraction varying from 95 to 98 per cent. Comparing the Porter processes to the ordinary cyanide processes, it will be seen that the Porter processes are adapted to nearly every kind of ore, while the ordinary cyanide methods are adaptable only to a certain class of ores.” – McPherson