Kennecott Eagle Minerals: 21st Century Mining

21st Century Mining

Mining methods in the 21st century need to meet 21st century values about environmental stewardship and social-well-being.

The most significant change in 21st century mining practices is centered on planning. New Rio Tinto mines are designed with closure in mind. This means that we plan our activities beginning with reclamation. Each stage of the planning process considers how the site will be left once mining ends. During permitting and operation, the company maintains a close collaborative working relationship with regulatory agencies to ensure compliance. Careful planning enables us to minimize our foot print while implementing best practice controls in communication, water management, and Brownfield redevelopment.

Communication is critical to a safe operation. At the Eagle mine, wireless routers will be installed at each level, with the main control dispatch center at the surface. A tag reading system will also be installed at critical areas to ensure all persons are accounted for within the mine.

Management of potential Acid Rock Drainage (ARD) is a key priority for the project. Development rock drawn from the underground access tunnel will be stored in a temporary holding area that is double-lined with leak detection and collection systems to prevent potential ARD. In addition, the development rock is mixed with limestone to neutralize the acid potential. Finally, the facility will be covered to prevent precipitation from contacting the rock.

Our surface facility grading plan was designed to separate surface water runoff into two categories: main operation area, and non-contact areas. Storm water runoff from the main operation area is collected in one of two lined contact water basins where it is stored.

All water collected from the temporary development rock storage area, as well as the contact water from the main operation area is routed through a state-of-the-art on-site water treatment plant, which will purify contact water to better than drinking water quality standards. Kennecott’s Humboldt Mill will also have an on-site water treatment plant.

Kennecott’s Humboldt Mill is an existing processing facility known as a Brownfield site. A Brownfield site is property with an environmental legacy. Cleaning up and reinvesting in these properties protects the environment, reduces blight, and takes development pressures off green spaces and working lands. One of the waste streams from a milling process is called tailings. Kennecott will reuse an existing tailings disposal facility located near the mill. The existing facility requires a sub-aqueous disposal method particularly suited to tailings containing sulphides. Sub-aqueous disposal permanently places tailings underwater, preventing oxidation and minimizing environmental issues associated with ARD. Kennecott will also use bottom placement methods to minimize changes to surface water quality.

We hope the information provided here gives you a sense of some of the activities associated with operating a mine today. At Kennecott and Rio Tinto we believe our mining techniques and the environmental controls put in place at our operations are best practice in the industry. We also believe that mining and a healthy environment can co-exist. Technology available today enables us to protect the environment and the outdoor activities our employees and the community enjoy. After all, we live here too.