Mercury Removal from Pressure Oxidation Vent Gas at Twin Creeks Facility

Abstract

Hatch Ltd. recently completed a project to substantially reduce mercury emissions from vent gas at Newmont Mining Corporation’s Twin Creeks refractory gold pressure oxidation facility. The objective of the project was to make each of the two autoclave circuits compliant with recent U.S. federal environmental regulation, per docket EPA–HQ–OAR–2010–0239. The optimal process design was determined through an assessment of various flow sheets and mercury removal technologies. The process was developed around existing constraints imposed by plant operations. Project implementation was supported through process test work, permit development, and process throughput validation. A detailed execution plan, including a 3D layout model, was used to integrate the new equipment into each of the two circuits during their scheduled annual downtime. This paper provides an overview of the process options evaluated, the project execution plan and the corresponding challenges, as well as resulting operational performance.