Exploratory Research Projects

The goal of this research is to develop biodegradable and effective eco-friendly materials for advanced dust control in mining industries. The materials under development are composed of synthetic polymer surfactants and natural cellulosic binders. When sprayed on dust-generating surfaces such as hard rock mine tailings, these materials stabilize the surface by molecular interactions between polymers and dust particles. In a test against a commercial dust suppressant product, these eco-friendly materials increased dust suppression by 85%. The research is focused on further enhancement of the dust-controlling capacity of these materials by replacing the synthetic polymer surfactants with biosurfactants developed by Dr. Raina Maier’s research group. Results thus far have shown that the biosurfactants demonstrate comparable dust controlling capacity when compared to the synthetic surfactants. The dust-suppressing capacity of these materials is being evaluated for both rock and coal particulates using tests based on an US EPA air quality index of “good” against wind speeds of 30 m/s (i.e., 67 mph) or more.

Number of students trained through this project: 1 postdoc and 2 graduate students

In efforts to reduce the knowledge gap and “unveil” environmental regulations, the goal of this project is to make selected environmental legislation and permitting processes that are applied to resource extraction activities accessible in plain language and in multiple media formats. Dr. Ramírez-Andreotta will work with CESM industry partners and select three major resource extraction policies and their associated state permitting processes and generate translational products in English and Spanish.

We are investigating a plant-based solution for the removal and re-use of metal(loids) from dryland ecosystems. This work has two interlinked aims. First, we will maximize the efficiency of metal phytoextraction through manipulation of the rhizospheric microbiome of (hyper)accumulator plants that are adapted to the arid US Southwest (University of Arizona - UA team). Second, we will utilize the resulting metal-enriched plant biomass in high-value catalytic reactions to create new metal-based eco-catalysts (ChimEco laboratory - CNRS team). The research is conducted using metal-contaminated mine tailings from the US Southwest. This region is a major producer of non-fuel minerals and has extensive metalliferous mine tailings sites of different ages, composition, and metal concentrations. Our pioneering work focuses on Zn, Mn, and Cu, which are important micronutrients for plant growth, but also major industrial pollutants of the terrestrial and aquatic environment. This innovative approach of this project has the potential to remediate metal-contaminated soils sustainably and profitably.

Number of students trained through the project: 6 (4 undergraduate, 2 graduate students)

Mine revegetation efforts in the Southwest are frequently challenged by the rapid encroachment of early successional plant species such as desert broom (Baccharis sarothroides). These species, although native, can impede the establishment of more desirable plant species. The effects of desert broom on the surrounding above- and belowground communities will be quantified to determine the benefits or hazards of desert broom in ecosystem regeneration during mine waste reclamation. Specifically, abiotic sensors are installed to measure soil moisture, soil temperature, and humidity underneath desert broom canopies and outside of the canopy. Additional other factors to be monitored both inside and outside the plant canopy include seedling density and identification, soil chemistry and microbial community composition. Soil biotic and abiotic properties will be compared to undisturbed native soils from surrounding ecosystems. Using these data, the effects of desert broom on the abiotic and biotic components of the local environment can be assessed and used to inform future management and reclamation efforts on hard rock mines.

Number of students trained through this project: 1 (graduate student)

Uranium mining in the U.S. Southwest has left thousands of legacy mining sites with uranium-contaminated soils. These soils are polluting adjacent water and land resources that, in turn, pose serious threats to human and environmental health. Uranium is also a challenge for modern mining operations as it is often present as a contaminant in mineral processing activities targeting other metals. In addition to uranium, rare earth elements (REE) are also often found as contaminants in coal and some hard-rock mining operations. There is interest in developing alternative REE sources domestically due to the importance of REE to consumer electronics, renewable energy technologies, and national defense.

Through Phase I Small Business Innovation Research grants, UArizona in collaboration with industry partner, GlycoSurf, has demonstrated two technologies capable of the selective removal of uranium and REE from complex mining solutions using rhamnolipid and other bioinspired surfactants: ion flotation and adsorbent materials. Matching funding from CESM is supporting this Phase II project wherein UArizona’s objective is to demonstrate the commercial potential of these technologies for reclaiming mining-impacted waters by:

1. Up-scaling reactor size,
2. Developing treatment processes for continuous flow operations and testing, and
3. Testing novel glycolipid surfactants.

This project aims to provide CESM mining partners with environmentally-friendly technologies suitable for generating new metal resource streams while concurrently reclaiming waters and reducing the environmental impacts of mining operations.

Number of students trained through this project: 4