Water and effluents management
Water is one of the most valuable natural resources. KGHM Polska Miedź S.A. regularly monitors the quality of ground and surface water in the vicinity of its plants to ensure that the Company’s activities comply with strict environmental standards.
Water is necessary for the production of copper. It is used, among others, for enrichment (flotation) of ore, hydrotransport of waste, and also in the core production line in the smelters. This is shown in the chart below:
Water in the ore enrichment (flotation) process
KGHM Polska Miedź S.A. has three operational underground copper mines, which mine the ore at depths of 400-1200 m. These are: the Lubin Mine Division, the Rudna Mine Division and the Polkowice-Sieroszowice Mine Division. Due to the constant inflow of water from the rock mass into the mines, approximately 60,000 cubic meters of saline mine water is pumped to the surface. Depending on the depth of the ore deposit, water may contain from 0.2 to 140 g/l of Cl- and about 2.8 g/l of SO42 Mine water extracted from deeper parts of the deposit are more salinated, but the volumes are smaller.
On the surface, retention reservoirs are located next to every mine and every ore enrichment plant. They collect rainwater, overflows of cooling water as well as extracted mine water. Water from the reservoirs is pumped into the flotation tailings ponds (in some cases mine water is pumped directly into flotation tailings ponds). As a result, neither mine water nor Effluents are discharged directly into local rivers. At the ore enrichment plants, all water is stored in closed systems and used for hydrotransporting flotation tailings to the Żelazny Most Tailings Storage Facility, where suspended solid particles are sedimented. Water from the Żelazny Most Tailings Storage Facility returns, through a system of decantation towers, to the ore enrichment plants.
Since there is a constant inflow of mine water and rainwater into the system, excess water must be removed. Water from the Żelazny Most Tailings Storage Facility is discharged by gravity through a 20 km long pipeline to the Odra river. The volume and quality of discharged water is closely monitored. The general rule is to keep the concentration of the sum of Cl- and SO42 below 1 g/l in the mixed water of the Odra river below the point of discharge. In practice, the discharged water. volume is controlled based on a formal table, which takes into account the current flow and salinity of the Odra river. The discharge permit also contains other provisions concerning the concentration of dissolved substances and the water flow rate. Water may be discharged only if the flow of the Odra river is greater than 17.5 m3/s and the flow of the discharged decanted water is less than 2 m3/s. The total level of suspended solids in the discharged water must be maintained under 35 mg/dm3. The size of the flotation tailings pond, especially its surface area, makes the sedimentation of tailings very effective and the overall level of suspended solids is usually kept below 35 mg/dm3. However, during windy weather, higher concentrations of suspended solids can be observed, which requires additional treatment. This situation is kept under control through continuous measurements of turbidity of the discharged water. If it is too high then the decanted water is transferred to a nearby effluents treatment plant to reduce the volume of suspended solids. After this treatment, the water is pumped into a pipeline which discharges it into the Odra river.
The Legnica Copper Smelter and Refinery and the Głogów Copper Smelter and Refinery consume significant amounts of water (approximately 11 million m3 per year), which is supplied by Energetyka Sp. z o.o. The company supplies water drawn from the Kaczawa river to the Legnica Copper Smelter and Refinery and from the Odra river to the Głogów Copper Smelter and Refinery.
The water used in production processes is routed back to Energetyka for treatment. Industrial effluents treatment plants operating for the smelters/refineries specialise in the removal of heavy metals, including arsenic, mercury and cadmium compounds, which are especially problematic. The effluents treatment technology relies mainly on neutralisation processes supported by coagulants and flocculants. Because of the high quality of effluents, approximately 30% of the global stream is reused for production processes in the smelters.
Approximately 8 million m3 of the remaining treated effluents are discharged to the Odra river (in the case of the Głogów Smelter and Refinery) and to the Pawłówka stream, which feeds the Kaczawa river (in the case of the Legnica Smelter and Refinery). The process is shown in the diagram below. The table presented under the diagram presents the measures linked to water management in KGHM Polska Miedź S.A. in 2021:
Water in the electrolytic copper production process
Water management by KGHM Polska Miedź S.A. In 2021
| Water withdrawal | [m3] | |
|---|---|---|
| Water withdrawal by source | Surface water (total) | 0 |
| Groundwater (total) | 176,815 | |
| Seawater (total) | 0 | |
| Water withdrawn as a result of operations, e.g. mine water (total) | 29,599,160 | |
| Fresh water (≤1,000 mg/l of total dissolved substances) | 0 | |
| Other water (>1,000 mg/l total dissolved substances) | 29,599,160 | |
| Water from third parties (total) | 12,117,706 | |
| Fresh water (≤1,000 mg/l of total dissolved substances) | 12,117,706 | |
| Other water (>1,000 mg/l total dissolved substances) | 0 | |
| Total water withdrawal | Surface water (total) + groundwater (total) + seawater (total) + post-production water (total) + water from other sources (total) | 41,893,681 |
| Water (effluents) discharge | [m3] | |
| Water (effluents) discharge by destination | Surface water | 27,815,093 |
| Ground and soil | 0 | |
| Sea | 0 | |
| Water provided to third parties | 9,530,140 | |
| Total water (effluents) discharge | Surface water + groundwater + seawater + third party water (total) | 37,345,232 |
| Water (effluents) discharge– fresh and other water | Fresh water (≤1,000 mg/l of total dissolved substances) | 9,614,815 |
| Other water (>1,000 mg/l total dissolved substances) | 27,730,418 | |
| Water consumption | [m3] | |
| Water consumption | Total water consumption | 4,548,449 |