Saturday, March 07, 2015

Florence Coke Ovens

I was curious about the history of the Florence Coke Ovens so I did a little Internet research. What I found has led me to believe the “coke ovens” were used to produce charcoal, not coke.

Most of the articles I read indicated that the ovens used mesquite to produce coke but they did not have enough detail or documentation to be as credible as I would have liked. This led me to look into the use of coke for smelting. What I learned is that coke is generally made from coal which is the process most steel mills use today. However, early metal refining companies also used charcoal which is made from wood. Given the abundance of mesquite in the area and the lack of coal, it seems more likely the Florence ovens used mesquite to make charcoal.

Here are excerpts from some articles that you may find interesting:
  • Cochran and the Coke Ovens: Who built them: “On a hillside across the Gila River you can see the bee hived shaped charcoal kilns. Many people associate them with Cochran and call them the coke ovens but they were there before Cochran was built. It is believed that the kilns were built by the Pinal Consolidated Copper Company in 1882 to supply their smelter furnace with charcoal. The site for the kilns was four miles from the smelter. The kilns were built along the Gila River to take advantage of the supply of timber, mostly mesquite which grew on the hill sides and along the river. A newspaper report from that year reported they were paying woodchoppers $2 per cord of wood." 
  • Hotter Than Mesquite: “The Arizona Highways book "Arizona Ghost Towns and Mining Camps" by Philip Varney speculates that the five charcoal kilns were built around 1882 along the Gila River by the Pinal Consolidated Mining Company to turn mesquite into charcoal to be used in the ore smelting process. Charcoal burns hotter and longer than the mesquite wood from which it was derived. Smelters preferred coke, which is derived from coal, because it would burn even hotter and longer than charcoal. The abundance of mesquite in this Gila Valley location was exploited by the mining company in an attempt to obtain economic advantage. It should be pointed out that "Coke Ovens" is a complete misnomer and "Charcoal Kilns" would be most accurate to describe these bee hive structures.”
I’ll leave it up to the erudite readers of this blog to analyze, debate, ponder, question and make the final determination.

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