Date of Defense

12-13-2021

Date of Graduation

12-2021

Department

Geosciences

First Advisor

Daniel Cassidy

Second Advisor

R.V. Krishnamurthy

Abstract

The wealth in the Upper Peninsula of Michigan has been intimately linked with mining, particularly the extraction of iron and copper. Iron was deposited in the Upper Peninsula 1.9 billion years ago (Gogebic and Ranges, 2020), and copper deposits are believed to be 1.1 billion years old (Blakemore et al., 2016). In the Upper Peninsula, mercury occurs naturally in taconite (iron ore) as elemental mercury (Hg0), and within the copper ores as “Mercury copper amalgam” (CuHg). When elemental mercury is released from the ores, it oxidizes in the atmosphere to form inorganic mercury (Hg2+) (Risher, 2003; Gaffney & Marley, 2014). Different forms of inorganic mercury have a different water solubility. For example, HgCl2 is very soluble, and HgS has very low solubility (Risher, 2003). The calculations show that each ton of taconite produces 0.02 g of mercury whereas a ton of chalcocite produces 3.2 g of mercury (Berndt, 2003) & (Kerfoot et al., 2004). The statistics show that the total iron productions between 1950 and 1980 was 408 thousand tons. The total copper production in the same period is 1.6 thousand tons. For 30 years, iron processes consumed approximately 6.1 thousand tons of coal. Chalcocite mining consumed only 12 tons of coal. Coal consumption is positively related to both iron and copper mining (Kerfoot et al., 2018). The total amount of mercury emission from iron mining is proximately 9 kg. The total amount of mercury emission from copper mining is approximately 5 kg. The mass balance finds that the total mercury in lakes sediments ranges between 0.01 to 0.38 kg/yr. In comparison, Where the total mercury in the lake water ranged between 0.01 to 0.28 kg/yr.

Access Setting

Honors Thesis-Open Access

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