Field testing for Rosemont mine reclamation

Jeff Conoyer, geologist at Rosemont Copper forwarded a description of a 7-year, $377,000 study they are funding at the University of Arizona to identify best native plants & options for land reclamation. The field test is on private ranch property owned by Rosemont Copper and because it is visible from Rte 83, it has prompted concerns from mine opponents that mining has started. According to the announcement,

Previously, Jeffrey Fehmi, Ph.D., assistant professor in the School of Natural Resources and Environment, and his team evaluated 29 different native species from around the Rosemont site compiled into four seed mixes. The local seed mixes were tested in the University of Arizona greenhouses using three types of soil from the proposed mine site, with several soil amendments and fertilizer combinations, and watered to simulate low, average and high rainfall years. The field testing is to verify these greenhouse results under real-world conditions.

The field testing is the third phase of the project, which will evaluate the established native species seed mix and methods, as they are exposed to the actual environmental conditions of the site. The field testing will involve test plots where numerous reclamation options will be evaluated. These include differences in site preparation (how smooth the surface is at the time of planting) and the use of mulch (none, mulch placed on the soil surface, and mulch incorporated into the soil). These differences in practice will be tested on two soil types expected to be used in the mine reclamation.

Establishing vegetation on the plots will help to hold soil in place and prevent soil erosion and loss while retaining water and air quality. Roots reach down into the soil and bind the soil beneath, while the plant cover helps to intercept the rainfall impact and to allow it to infiltrate the soil.