Birdsall-Dreiss lecture series tackles mining lithium and hydrogeology
On October 25, 2018, David F. Boutt of the University of Massachusetts Amherst visited campus to deliver a talk entitled “Water and Lithium – The nexus of hydrogeosciences and green energy in the transition from fossil fuels.” David delivered the talk as a part of the Birdsall-Dreiss distinguished lecturer series. The Birdsall-Dreiss lecture series is sponsored by the Hydrogeology division of the Geological Society of America (GSA). The Birdsall-Dreiss lecture tour series lasts the entire year and spans 58 total institutions. Beloit is the 51st talk that was given this year.
The talk that Boutt gave entitled “Water and Lithium – The nexus of hydrogeosciences and green energy in the transition from fossil fuels,” focused primarily on the process of mining lithium. His talk highlighted the typical association of hydrogeology with more environmental applications, such as monitoring the spread of pollutants through the groundwater. However, with the production of lithium David explained that hydrogeology is able to break the typical mold and find an unlikely pairing with more of an economic geology interest. David’s talk focused primarily on how hydrogeology can be useful to lithium extraction. He also wove the environmental impacts that lithium mining has on the Salar de Atacama, a large salt flat, in Chile.
There are two main ways to extract lithium from the earth for use. Pegmatites, which are the last part of a magma to crystallize often contain an assemblage of various minerals. In order to be considered a pegmatite all the crystals must be at least one centimeter in diameter. Lithium was historically mined from these types of rocks, however they are not as effective as the other method of lithium mining. Most of the lithium that is mined today is done so through so called “continental brines. These brines are typically found in arid areas where there is a higher rate of evaporation than precipitation. The main producers of lithium through this method exist in the Chile, Bolivia and Argentina area.
The production of lithium through this method begins through the water cycle. Rainwater that is rich in lithium rains on the area increasing the concentration of the brine. Meanwhile in the subsurface, lithium is able to be transported by groundwater since it is a very light element. The groundwater that is rich in Li, is discharged at the surface in the basin. In the Salar, the arid environment allows the lithium to crystalize like a salt. This final process of crystallization removes the water and increases the lithium concentration even higher. This perfect blend of processes allow the Salar de Atacama to be a massive producer of lithium compared to traditional processes.
As a part of his talk, Boutt spoke about the environmental implications that this type of mining would have on the area. One of the major issues that Boutt and other researchers have found is they have been unable to find where groundwater recharge occurs for this area. Other researchers who have studied the Outlet Rivers from the Salar, also had a similar issue when they were trying to construct a water budget of the area. The groundwater that is instrumental in the production of the lithium brines also feeds into these outlet rivers. The overall environmental impact that the actual removal of Lithium from the area, has a minimal environmental impact. However it is the pumping of groundwater that would prove troublesome, as it would impact other marginal freshwater systems. Under current mining conditions the lagoons are shrinking which would be exacerbated by further pumping. The locations where groundwater surfaces in the Salar is dynamic and evolves dramatically to create unique environments that are important landscape features to the area. To end his talk Boutt, recommended alternative battery technologies to that of the lithium ion battery.