VICKSBURG, Miss. — Researchers from the U.S. Army Engineer Research and Development Center’s (ERDC) Environmental Laboratory are currently assisting the Dominican Republic and its regional government agencies in the hunt for rare earth elements (REE). REEs are specific metallic elements found on the bottom of the periodic table and used in many modern technologies including cell phones, computer hard drives and flat-screen televisions.
The Department of Defense (DoD) in collaboration with the Department of State (DOS) embassy in Santo Domingo, Dominican Republic (DR) sent out an initial request for an Embassy Science Fellowship (ESF). The purpose of the ESF was to provide technical assistance to the DR government – specifically, the Ministry of Energy and Mining (MOEM) and the National Geological Service – in the geochemical exploration and potential exploitation of REEs in remote areas of the DR.
Dr. Mark Chappell, a Senior Scientific Technical Manager at ERDC with substantial expertise in soil geochemistry, responded to the request. He and his fellow team members, Dr. Yoko Slowey, Charles Andros, Christine Young, and Paige Fowler conducted a three-month preliminary study to address two fundamental objectives: determining the distribution areas of REEs throughout a portion of the DR and the amount of REE concentration in each area.
“For the mission, we were stationed on the western edge of the DR along the Haitian border. We worked with MOEM members to explore the highlands of the Pedernales District for REEs,” Chappell said.
The DR discovered they had particularly high and rare elements but needed the resources and expertise to define the size of the areas and the concentrations available to determine if the elements were economically viable to exploit them.
“What makes REEs rare is finding them in concentrations high enough to make mining them economically feasible,” Chappell said.
Only specific types of sensors known as portable x-ray fluorescence technology can be used to detect these elements remotely, without the need for a dedicated laboratory facility. Chappell and his team used handheld x-ray and color sensors to collect data in the DR and then sent samples back to ERDC’s Environmental Laboratory to create a calibration model for predicting REE concentrations through laboratory geochemical studies.
The team also utilized one other alternative for exploration. The Caribbean region of the World possesses soils rich in aluminum which gives it a rusty red color. “There is a correlation between the color of the soil and the REE concentration,” stated Chappell. “We utilized our knowledge of soil geochemistry and the equipment we possess to search for REEs in their mountainous areas.”
The researchers concluded there was a high existence of REEs in the soil throughout the region, increasing the likelihood that the exploitation of these resources would be environmentally sustainable.
Briefings of the researchers’ findings were provided to the President of the DR, as well as a proposal of the next phase which consists of obtaining U.S. Army Corps of Engineers Foreign Assistance funds to perform a deeper exploration of how the REEs can be chemically extracted.
These ERDC researchers demonstrate the global impact of work happening in the Environmental Laboratory at ERDC. “Our expertise in the environment is singular throughout the DoD. No one else has this sort of expertise and can apply it to DoD issues,” Chappell said. “We do this not only from an environmental/regulatory perspective, but from a mission success one as well. That is the strength EL brings to the table.”