The best possible water treatment for the mine in Kolari
In February, 2018, Hannukainen Mining concluded a partnership agreement with Teollisuuden Vesi Oy, which has long experience of treating mine and industrial water, as well as expertise in microbiology. Through the partnership agreement, the planning of water treatment in for the Hannukainen mine now includes world-class water treatment expertise. The goal is to find solutions that reduce the content of harmful substances to the extent that they become insignificant.
The calculations in the environmental permit application, for example, have become more specific as cooperation has begun between Teollisuuden Vesi and Hannukainen Mining.
Water treatment planning is based on the lowest possible clean water usage in the process and water recycling within the concentration plant by means of clarification and
The emissions load of sulphate will be at its highest in very rainy years. In years with little rain, sulphate loads are low. That is why water treatment plans must be taken into account and the environmental effects must be examined in the long run.
”Exposure to sulphate, for example when swimming, does not pose a risk to users of the water system.”
Efficient use of water
The ore mined from the open pits at Hannukainen and Kuervitikko is concentrated at Rautuvaara. The concentration process consists of multi-phase grinding and flotations, magnetic separation, thickening of solids, and filtering of concentrates. Chemicals used in the concentration process include:
- pH regulators
- foaming agents
The desired characteristics for air bubbles transporting minerals in Efficient use of water flotation, is obtained from foaming agents. Collectors make certain minerals stick to air bubbles during flotation and thereby separate them from other solids. Scavengers, for their part, prevent certain minerals from sticking to air bubbles. In addition, the flotation features of different minerals can be affected by adjusting the pH. In addition to the aforementioned chemicals, flocculants are used in the thickening of solid matter.
The process at the concentration plant requires little water from outside the mining area. Most of the water needed is obtained from internal circulation as the excess from the thickening of solids carried out at different stages of the process.
In addition to this internally circulating water, the process takes approximately 100 m3/h of water from the clarification pond, which is mainly water pumped from the open pits. By using only a small amount of water from outside the concentration plant, it is possible to minimise the effects on the surrounding water systems, because this also means that the amount of water removed from the plant can be kept low. All the water removed from the water circulation of the concentration plat is purified.
”All the water removed from the water circulation of the concentration plat is purified.”