Key mechanisms for successful reclamation
Abstract
The Golden Cross Mine is located on the North Island of New Zealand, at the base of the Coromandel Peninsula, approximately 8 km northwest of Waihi. The project is operated as a Joint Venture with Coeur Gold New Zealand holding 80% and Viking Mining Limited with a 20% interest. The past open-pit and underground gold and silver producer has been in reclamation phase of the operation for approximately 2.5 years and this phase is now nearing completion. Although rehabilitation of the site is a regulatory requirement, the Closure Plan has been enhanced by the ongoing commitment of the Joint Venture to establish a sustainable land use for the site by commissioning engineered facilities designed to last for perpetuity.
The Joint Venture identified six significant design features that were key to successful rehabilitation. These were the controlled placement of acid-generating waste rock into engineered disposal sites; the design and placement of sealing layers over the waste rock disposal sites; the design and construction of diversion drains; the establishment and management of vegetation to protect the rehabilitation layers; a partial capping of the tailings to accelerate consolidation adjacent to the tailings dam embankment, and the implementation of a recovery circuit to recycle cyanide from the tailings prior to disposal.
Another key to success for the project involved genuine consultation with all parties participating in the planning, evaluation, and consenting of the closure process at Golden Cross. The local and regulatory community has been widely represented in the Joint Venture's operating and closure planning throughout the history of the mine. Participants include: Regional and District Councillors and staff members, professional peers reviewers, environmental groups, local residents of the valley, and Iwi.
This overall commitment to the project has resulted in a world-class rehabilitation program for the first modern metal-mine closure in New Zealand and we believe that collectively, the work done at Golden Cross is helping to set a standard for the success of future programs within the extractive industry.