Vadose Zone Infiltration Assessment, Numerous Mining Projects
Integral hydrologists and geochemists have conducted numerous studies addressing infiltration and solute transport through the unsaturated zone beneath tailings impoundments, waste rock storage units, and process water land application areas at mining projects throughout Nevada. At the Twin Creeks mine, Integral scientists developed a numerical model of unsaturated zone flow and transport to estimate cyanide flux rates from a tailings impoundment. This model was developed in support of a permit application to expand the tailings facility. Key technical tasks included estimation of moisture movement and cyanide mass flux under existing, proposed, and post-closure conditions. Related laboratory studies evaluated the effectiveness of various oxidants to destroy cyanide and cyano-mercury complexes. These efforts successfully demonstrated that installing wick drains in the tailings would offset the increased seepage and cyanide flux caused by raising the impoundment, and that seepage would drop substantially soon after closure.
At another Nevada mining project, Integral staff evaluated sources of elevated nitrate and metals in groundwater downgradient of a tailings effluent discharge. Field, laboratory, and modeling evaluations demonstrated that subsurface nitrate detected in groundwater originated from dissolution of a natural caliche layer, not from the tailings effluent water.
This project reflects Integral staff experience gained under previous employment.
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