Martinez Mine Mill

Martinez mine and mill are located in the Martinez Canyon by way of the Box Canyon.  To visit the site 4 WD vehicles are needed with an approach from northeast of Florence, AZ.

There were numerous mining claims in the Martinez Canyon dating back to the 1880s.  The main minerals at the sites contained silver, lead, zinc, gold, and some copper.  The Martinez mine which had a high lead and low silver ratio has been developed approximately 900 feet long to a depth of 200 feet on an incline.  The Martinez Mill is fairly well preserved with much equipment still in place, although it is hard to tell the functions of various pieces.  The mining claims have been abandoned since the 1950s and is now part of BLM land.  The trestle over the valley may have been used to transport the ore from the mine on the opposite side.

19th century mining methods depended upon finding various minerals on the surface or with some digging in following a vein of the ore.  Quartz deposits were sought because they may have contained gold and silver. Towards the end of the 1890s compress air drills may have been used to break rock close to the ore vein.  The various ore pieces were hand picked from the waste rock for further processing at the mill.  Various types of stamping mills which were steel cylinders powered by steam were used to crush the rock to a very fine dust.  A stamp mill was not in evidence at the Martinez Mill, but there was an air compressor.

To concentrate and recover gold when present as free metal particles of gold and silver, the finely ground particles were washed over tables with baffles so that the heavy silver and gold particles sank to the bottom.  Other metals such as lead and copper could also be concentrated in this manner.  A final treatment with a thin layer of mercury caused the gold to be made into an amalgam.  At the beginning of the 20th century, ore deposits were becoming more complex and the mercury method gave way to using solutions of sodium or potassium cyanide which dissolves the gold.  It is hard to discern if these methods were used at Martinez.

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