Lead Mining

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The state of Wisconsin is known for its dairy products and rich farm land, but what most people don’t know is that in the mid 1800’s Wisconsin was a major iron and lead mining state. The potential for quick reward attracted people to Wisconsin as settlers looked to explore and make money. The cities of Mineral Point, Hardscrabble, New Diggings, Black Jack and Iron Ridge are just a few of the cities in the state of Wisconsin known for their mineral rich soil and successful mines. [1]

Early Mining

Lead Mining has been around for thousands of years. Geologists have been able to date iron ingots found in the Mendip Hills in Great Britain all the way back to AD 49. [2] The earliest lead mining in Wisconsin was mentioned was back in the early to mid 1600’s. It is common thought to most people that modern lead mining didn’t start until the boom in the 1820’s, that assumption would be incorrect. As Wisconsin historical society explains, lead mining dates to 1634 when the Wisconsin & Illinois Indians were visited by the Nicolet. The Native people were superstitious with regards to minerals and made it a point to keep the whereabouts of the precious minerals a secret. It wasn’t until the 1630’s when they made the location of the mines known to the white settlers.

The region shared with the French at that time some three hundred eighty years ago which included parts of Wisconsin, Illinois, Iowa, and Missouri came to be known as one of the “richest lead baring regions in the world.”’. Once this region was made known to the French settlers, the tales of the tracts mineral rich grounds became widespread. It was the French who first introduced firearms and the idea of large-scale hunting to the natives. This made lead more valuable to the natives, not only for use in bullets, but as a “article of traffic” in trade with the settlers. [3] For more information on mining in wisconsin, please see Mining in 19th Century Wisconsin

Modern Lead Mining

Lead Mining is still around some 2000 years after its discovery. Almost all the mines in Wisconsin have since been shut down and decommissioned. There are still some mines operating in the U.S. In 2013 there were 9 active mines, down from 19 on 2000. In 2013 the United states accounted for only 6% (.33mt) of the lead mined in the world. At this point, 91% of lead used in production comes from refineries which produce lead by recycling old batteries and refining it for reuse in other products. In 2013, 1.15Mt (metric Tons) of lead was refined in the United states. The refining is done mostly by battery producers who reuse the lead to produce lead-acid batteries. While lead mining is on the decline, the secondary production and use of lead in products actually increased from 2012 to 2013. [4]

How Lead is Mined

Lead like many other minerals is found underground and through the use of mines, lead ore is taken from the earth for use in products. Lead is actually considered a byproduct of other minerals. There are sixty plus minerals that contain lead, but only 3 of these minerals are considered viable sources to obtain lead; 3 galena, cerussite and anglesite. Lead is also found in conjunction with silver and zinc, but for commercial purposes only those three are used.

The process of extracting lead from these other minerals is a complex process. First lead ore is ground into very fine pieces, smaller than .1mm (comparable to a grain of table salt). Next the lead powder is mixed with water & pine oil. This along with air bubbles and further agitation creates an oily type liquid in which the lead ore sits on the surface. The lead ore is skimmed & filtered to remove water and other toxins. The remaining lead ore is sintered at and extreme temperature (2500 degrees F). this is done to oxidize and further remove any leftover toxins such as Sulphur. The leftover powder is again heated in a blast furnace; the carbon produces molten lead. The molten lead is then cast into lead molds. At this point the lead then goes through several other processes to improve purity. Once the lead is 99% pure, it is cast into lead blocks that can be shipped and used to make other products. [5]

Lead Uses

Lead having been around for thousands of years has been used in a wide array of products. The ancient romans used lead to craft water pipes, as well as a coating for ceramics. The ancient Egyptians used lead as a makeup to darken their eyelids for ceremonies. In the late 1800’ss to early 1900’s lead was used for bullets, paint and other various coatings, grave linings, glasses and pipes. After WWI with the introduction and increased popularity of automobiles which often used lead-acid batteries to start the engine. Along with the use of lead in video display equipment and radiation shielding, lead was also used as an additive to gasoline. These new found uses further added to the increase in demand for lead.

By the 1980’s environmental regulations caused a massive shift away from lead usage. This along with the introduction of more effective alternatives in products such as paint, water pipes, and gasoline. Today, lead is mainly used in batteries, ammunition, casting metals sheet lead and oxides in glass and ceramics. [6]

References

  1. Wisconsin Mines, 2016, Mining artifacts.com, http://www.miningartifacts.org/Wisconsin-Mines.html
  2. Minerals and Mines: The History of Lead, 2011, "British Geological Survey", Accessed April 27, 2017, https://www.bgs.ac.uk/mendips/minerals/Mins_Mines_2.htm
  3. Notes on Early Lead Mining in the Fever River Region, 1853-1913, State Historical Society of Wisconsin (Madison, WI: 1895), accessed May 2, 2017, http://content.wisconsinhistory.org/cdm/ref/collection/tp/id/47255
  4. 2013 Minerals Yearbook, 2015, United States Geographic Survey, Accessed May 1, 2017, https://minerals.usgs.gov/minerals/pubs/commodity/lead/myb1-2013-lead.pdf
  5. Lead Materials-Ore Extraction, 2008, Nuclead, Accessed May 1, 2017, http://www.nuclead.com/leadmaterials.html,
  6. Uses of Lead, 2005, Geology.com, Accessed May 1, 2017, http://geology.com/usgs/lead/,


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