Most of the waste that Glencore generates is mineral; it includes tailings, slag and rock. Our assets have rigorous management systems in place to dispose of waste while preventing environmental contamination. We continuously review our waste management processes, and identify and implement opportunities for improvement. We reuse as much waste as possible. For example, we use waste rock to backfill our mines, and fill roads with non‑hazardous tailings.
Dealing with tailings
Our metal and coal assets generate tailings (residues of mineral processing), which are stored in purpose-built tailings storage facilities. These are specially designed ponds filled with tailings and water; over time, the water evaporates while the tailings settle, gradually filling the dam.
At this point, the dam is capped, sealed and rehabilitated. Our tailings facilities are monitored continuously for integrity and structural stability. Flooding and seismic activity are the main natural phenomena that may affect them. Our assets evaluate natural phenomena and incorporate these considerations into their tailings facility designs where relevant.
Safety of tailings facilities
In 2014, we conducted a survey of all Group tailings facilities, supervised by the Board’s HSEC Committee. The survey investigated the key characteristics, risks and controls of our tailings facilities, as well as their design and construction. Glencore’s corporate sustainability team analysed the results and presented the key findings to the HSEC Committee, which requires all surface tailings facilities to undertake an independent inspection no less than every three years.
Our 2016 assurance programme included a review of all priority tailings facilities by subject matter experts. These assessments will be peer reviewed. We have also reviewed and updated the critical controls for tailings facilities in our RiskManager tool, to help our assets develop catastrophic hazard management plans.
We comply with relevant regulatory limits and international standards wherever we operate.
Our metallurgical smelters emit sulphur dioxide (SO2), dust and nitrogen oxide (NOx) as both stack and fugitive emissions. Stack (or point) emissions emanate consistently from a fixed source (such as a smelter furnace), whereas fugitive emissions emanate irregularly from diffuse sources.
Our open-cut mining assets emit dust (also referred to as particulate matter or PM) during excavation and when moving material. We monitor dust levels within affected communities and minimise dust in a number of ways that includes dust suppression, construction of berms to prevent dust travelling to communities, optimising our blasting activities, watering our haul roads and using protective coatings on product and waste storage facilities.