Last week we introduced you to tailings. Tailings are a part of mining that get a lot of publicity, and managing them responsibly is a key environmental component of our business. While each operation is unique, our approach is to ensure that the environment is protected during and after the operation has closed. Here, we discuss our Tanjianshan tailings facility in more detail.
Tailings are a mixture of solid particles, mostly rock, and water that is left over after the gold extraction process. Tailings must be managed and disposed of safely, so that any impurities do not adversely affect the environment, local communities, or biodiversity in the area.
The tailings management facility at Tanjianshan, China is located about one kilometre downstream from the processing plant. It has a maximum height of about 40 metres, and is double-lined with a geo-membrane layer and a high-density polyethylene liner. These liners ensure no remaining chemicals leach into the soil or groundwater below, and a groundwater collection system is installed beneath the facility to allow any groundwater coming to the surface to drain out to a collection dam.
The tailings facility was designed by an internationally-renowned company and independently checked by a state-owned Chinese engineering company. It was then approved by the state authorities to ensure that international and national standards were met. Construction was supervised by both the original designer and site personnel to make sure it was built as designed. Currently, there are three tailings dams in the facility at Tanjianshan: one under closure, one to be built, and one in operation.
Routine inspections by government authorities, the original designer and site personnel are carried out and recorded to ensure there are no leaks. The tailings facility is operated with zero discharge of any process solids or solutions. Once the tailings material settles (the solids sink and the process solution is left on top), the process solution is collected and reused in the process plant. Groundwater both upstream and downstream of the tailings facility is monitored, and sample results are reported to government authorities. All three of the tailings dams at Tanjianshan have zero non-conformance records – there have been no leaks out of the tailings facility, and the surrounding environment has not been affected.
Tanjianshan’s tailings facility is only one example – Eldorado takes pride in our tailings management practices around the world. In the past year, we’ve had all of our tailings facilities audited by an independent tailings management and stability expert, to triple-check for risks. We are also working towards having all of our operations align with the Mining Association of Canada’s Towards Sustainable Mining Tailings Management protocol.
Did you miss our introduction to what tailings are all about? Check out our tailings management 101.
Find out more about Eldorado’s approach to protecting the environment.
Next week, we’ll tell you about how we’re rehabilitating a tailings facility from a previous mining operation in Greece. Subscribe so you don’t miss it!