VERDE HERITAGE 1927: CLARKDALE; New Concentrator Recovers Elusive Ores.
"Just one year ago the embryo of a building designed to house the concentration plant of the United Verde Copper Company at Clarkdale, poked its nose skyward as another monument to mining men. Today that plant is completed, and although not operating to full capacity, its product in the form of valuable ore is streaming on an endless belt toward other steps leading to the production of pure copper. This new process, redeeming as it does, precious metals that were lost for many years is the realization of the dreams of those mining pioneers who 'knew it was there but didn't know how to get it.'"
"At the present time only one of the concentration floatation plants is in operation. Another unit is now under construction and will be placed in operation early next month, according to Chief Engineer J. E. Lanning. This single unit is treating 450 tons of ore per day with the possibility of a greater production with the completion of minor changes now under way."
"The total capacity for the two units is estimated at 1200 tons of ore per day. The concentration plant is employing 26 operators who will also operate the other unit upon its opening in May. The simplicity and efficiency of these plants enables a minimum of hands for successful operation thus the arrangement for a non-enlarged crew when production soars."
"WASTE IS TAILINGS: The fundamental idea of concentration and floatation is to deliver the waste material to the tailings dump instead of the slag dump. The process not only puts great tonnage of waste material on the tailings dump but improves smeltering conditions because a more easily handled product is supplied to the furnaces."
"The installation at the Clarkdale smelter is synonymous to general progression of all big producers; not only in copper but in lead, zinc and other complex ores. The history of all mining camps is parallel in that they usually begin working high grade ore and later, due to higher mechanical and metallurgical processes they utilize the lower grade ores and return profit."
"'This process of concentration or the recovery of low grade ore at the smelter is not designated to increase our production of copper,' said Chief Engineer Lanning, 'but instead it is an important economical factor in our operation.'"
"'At the present time many low-grade properties are being worked as the result of the development of the concentrator, that had never been exploited prior to this time. Many cases in the Lake Superior region show a tremendous profit by retreating the tailings of previous workings from values which were not recovered with old processes.'"
"MECHANICAL PROCESS: Concentration at the Clarkdale smelter is no more than a mechanical means employed to separate, as completely as possible, the metal-bearing mineral from the non-metallic, worthless substances, or even to separate two or more minerals, worthless when mixed with the ore, but valuable when separated. The concentration and floatation process differs from the smelting process in that it is purely mechanical in nature while smelting involves chemical activity."
"'These marvelous new methods, new machinery and new processes have made possible the recovery of metals from lower grade ores,' said Mr. Lanning. 'This has in turn increased the values of the mines and prolonged the prosperity of the community.'"
(Verde Copper News; Jerome; Tuesday, April 19, 1927; page 1.)