Hannukainen Mining's goal is to make the Kolari mine as clean as possible
The goal of Hannukainen Mining is to make the Kolari mine as clean as possible. Mine planning is a longterm activity. The operation is based on solutions proven to be safe. During the operations, we will seek to develop new solutions and models that can be productised and used in other mines around the world.
”We test, pilot, study, and develop water treatment for as long as needed to be certain that the discharge water from the mine is not harmful to the environment.”
Mining operations cause all kinds of noises. Noise is caused by blasting, mining, crushing, and traffic. To minimise the environmental impact mining operations cause, we measured the environmental noise and vibrations of the Hannukainen mine and surroundings during the test operations between July 11 and September 14, 2017. Noise monitoring was carried out even before work began, so that the background noise, too, could be taken into account. The effect of mining operations on noise levels in the area was examined on days when blasting took place and the ore was piled at the mine site.
The noise from work done in the mine site, blast signals, and the actual blasting could be clearly heard at measuring point MP1, located closest to the test pit. These sounds were also heard at measuring point MP2, albeit more faintly.
Blasting sounds could be variably heard at measuring points MP3, MP4, and MP5.
At these points, blasting sounds are at times covered by traffic and wind noises. At the other measuring points, the sounds could not be distinguished from ambient noise.
In sum, based on the measurement results, mining operations do not play an important role in the sound levels in the area.
In mining operations, particle emissions tend to be caused by heavy traffic and machinery, mining, loading, and the crushing of ore and waste rock as well as the storage of tailings.
Concentrations of inhaled particles have been measured at Hannukainen and Rautuvaara, using automatic analysers in continuous operation. The purpose of the measurements was to survey basic air quality at the mining sites of Hannukainen and Rautuvaara, before the potential commencement of new mining operations.
With regard to the piles of waste rock, dust emissions will tend to occur in the summer time, because the waste rock is covered in snow in winter. In the summer, dust emissions will be minimised by the adequately coarse size distribution of the material being dumped and through watering. In addition, dust emissions can be minimised so that the part of the waste rock area already finished is landscaped.
Heat will be generated by the blasting, due to which the snow will melt and absorb dust. The amounts of dust created during blasting will be relatively small compared to the overall scale of the mine, and occur for only a short period of time. Their proportion of total dust emissions will be small. The dust reduction measures will be specified in greater detail as the planning work progresses, and during production. At the start of the operation, we will monitor the fallout with dust collectors.
Vibrations were continuously measured at five measuring points. The measurements were performed using 3D vibration gauges. The gauges were installed in the foundations of residential buildings.
The vibration results were in the range between 2.0 and 12 mm/s. Based on the audio data, the vibration was caused in the vicinity of the measuring point by activities related to normal living.
During blasting, the vibration was below 2 mm/s at all the measuring points. The first blast was performed in the test pit VE2, located at a distance of 690 metres from measuring point MP2 and 1,800 metres from measuring point MP12. Other blasts were performed in test pit VE3, located at a distance of 830 metres from measuring point MP2, and 1,600 metres from measuring point MP12.
No vibrations caused by the blasts could be detected in the buildings.
No plans yet exist on the lighting of the Hannukainen mine site or the Rautuvaara concentration plant, so the evaluation of the landscape effects of lighting is based on the assumed intensity and location of the lighting. In areas related to the mining project, there is a need for lighting in the industrial areas and the area being mined around the clock.
Because the lighting is focused on active working areas, little scattered light will occur elsewhere in the surroundings or the sky.
In addition to the mine site and its immediate surroundings, lighting will affect the landscape at night. For example, the lighting in the Rautuvaara and Hannukainen areas, as seen from Yllästunturi, is detected as new light points in the otherwise rather dark landscape.
The lights of the mine do not prevent aurora from being seen in areas with a focus on tourism. This was confirmed at the open pit mine of Boliden Aitik in Gällivare, where mining has been going on for several years.
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.”
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:
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.”