Load on waterbodies clearly below permit quota

Environmental monitoring of the mine continued in accordance with the approved, extensive monitoring programme. The amount of stored water was brought to the target level, and the load on waterbodies released into the environment decreased compared to the previous year.

During 2017, the amount of water stored at Terrafame’s site was brought down to the target level of 1–3 million cubic metres, and the storage of water no longer posed a major risk. The amount of purified water released from the site totalled approximately 5.3 million cubic metres, which is approximately 4.3 million cubic metres less than in the previous year.

All the water discharged from the site was released north into the Oulujoki watercourse area. Thus, no water was discharged into the Vuoksi watercourse area. Most of the water was released via a discharge pipe into Lake Nuasjärvi. In May, around 0.4 million cubic metres of water was also released via Latosuo into the north-bound discharge route.

As in previous years, the substance concentrations of water discharged into water bodies were low and clearly below permit levels, apart from individual exceptions. A clear deviation occurred in water treatment when the aluminium content of discharge water increased in late autumn. The aluminium permit level was exceeded in October and November due to disruption at the central water treatment plant. The plant’s operating parameters were modified, and the aluminium content returned to its normal level for the remainder of the year.
 

Amount of water stored at the site, 1 September 2015–31 December 2017.

 

Average concentrations of purified water released from Terrafame’s site in 2016 and 2017.

 

In 2017, according to confirmed analysis results, the sulphate load resulting from purified water released from the site was 10,468 tonnes, which was about one third less than the maximum amount permissible by the environmental permit. Particularly positive is the fact that the total sulphate load decreased by more than 7,000 tonnes from the previous year.

The most exceptional situation in water management occurred in August in the separate waste rock area (KL2) under construction east of the open pit. In a disruption caused by human error, metallic water flowed into the Pirttipuro route for about 24 hours, resulting in an extra nickel load of about 100 kilogrammes. The metallic water was directed into the purification process as soon as the situation had been registered. Additional water samples were drawn from Pirttipuro and Talvijoki and, based on them, environmental impact was limited to a short period.


Loading on water bodies resulting from the operations

Discharge pipe

Loading
2017
Discharged
(m3)
Copper
(kg)
Manganese
(kg)
Nickel
(kg)
Zinc
(kg)
Sulphate
(t)
Sodium
(t)
January 329,855 0.3 422.9 20.4 25.2 1,043.1 151.0
February 325,261 0.5 348.6 17.7 21.1 803.0 116.7
March 192,927 0.2 216.0 8.8 10.1 496.3 104.7  
April 49,661 0.1 46.6 1.1 2.2 194.9 61.1  
May 519,091 0.5 419.4 19.3 18.4 1,226.0 413.6  
June 708,005 0.8 223.1 17.0 19.5 1,098.1 254.2  
July 692,779 0.8 94.7 11.5 11.9 1,002.6 201.6  
August 220,350 0.2 49.8 7.5 14.3 411.3 91.2  
September 546,058 0.5 115.3 12.1 21.9 1,026.3 181.4  
October 703,730 0.7 113.0 11.2 16.9 1,407.0 230.8  
November 112,316 0.1 160.2 1.7 2.0 237.0 48.1  
December 523,573 0.9 773.7 13.0 18.0 992.7 176.0  
Total 4,923,605 5.7 2 983.4 141.3 181.5 9,974.5 2,030.2
Permit limit (43/2015/1)   100.0 20,000.0 350.0 525.0 15,000.0 4,000.0
               
Between 15 March – 5 May the discharge pipe was used only as much as was necessary to keep the pipe free of ice.
Water was not discharged from the mine area between 6 – 13 August.
 

Old discharge routes

Loading
2017
Discharged
(m3)
Copper
(kg)
Manganese
(kg)
Nickel
(kg)
Zinc
(kg)
Sulphate
(t)
Sodium
(t)
South 0 0 0 0 0 0 0
North
(8–30 May)
355,772 0.4 249.4 18.3 26.9 493.2 119.4
Total 355,772 0.4 249.4 18.3 26.9 493.2 119.4
Permit limit (52/2013/1)   150.0 2,600.0 250.0 300.0 1,300.0 650.0
               

Total

Loading
2017
Discharged
(m3)
Copper
(kg)
Manganese
(kg)
Nickel
(kg)
Zinc
(kg)
Sulphate
(t)
Sodium
(t)
Discharge pipe and old routes 5,279,377 6.1 3,232.8 159.6 208.4 10,467.7 2,149.6  

The condition of the lakes below the site in line with expectations

The impact of purified water was visible during 2017 in Lake Nuasjärvi mainly as increased electrical conductivity and concentrations of sulphate, manganese and sodium in the basins closest to the discharge pipe. The lake’s seasonal overturns extended to the entire mass of water during both the spring and autumn overturns, and discharge water did not prevent normal operation of the lake.

In the small watercourse areas of the old discharge routes on both the Oulujoki and Vuoksi side, the situation remained either unchanged or improved slightly. Lake Salminen and Lake Kalliojärvi in the Oulujoki watercourse area route have continued to be stratified. The sulphate concentration in Lake Kolmisoppi and Lake Jormasjärvi is gradually decreasing, thanks to the decrease in the sulphate load on old routes. During 2017, Terrafame released no water into the Vuoksi watercourse area. Thus, a reduction in sulphate concentration continued to be visible in the water route. Lake Kivijärvi, part of the Vuoksi watercourse area, has stratified basins as a result of operations from years ago, but in some of the shallower basins, water circulation has occurred.

Impact on groundwater under close scrutiny

Terrafame has an extensive groundwater monitoring programme, the goal of which is to gain information on the surface level and quality of groundwater. There are 24 rock groundwater pipes and eight earth groundwater pipes pertaining to the monitoring programme in the mining concession area.

Furthermore, the monitoring programme has eight domestic water wells in the vicinity of the mining concession area. In addition, the quality of groundwater is observed through one domestic water well and through two wells in connection to water intake plant in the Nuasjärvi impact area.

In February 2017, Terrafame submitted a report to the supervisory authority on the groundwater in the primary leaching area and the neighbouring area of the Kortelampi dam, as well as the measures to minimise environmental impact. According to the report, there are observable changes in the quality of groundwater resulting from industrial activity in the areas examined. Groundwater impact was monitored more rigorously during the year under review and improvements were made to the protective structures of the leaching solution collection system in the primary leaching area.

Dust impact slightly less than in the previous year

Mining operations and ore crushing always cause a certain amount of dust impact. This is monitored by measuring the amount of particles emitted into the atmosphere, and by fallout surveillance, which is used to monitor the amount and quality of solids deposited from the atmosphere onto the production area and its vicinity. The metals production plant also produces air emissions, which are monitored by measuring the concentrations of metal, hydrogen sulphide and sulphur dioxide in air emissions.

Efforts were made to reduce dust impact by, for example, watering roads in the production areas. According to surveillance results from 2017, the dust impact of operations was at its highest at the mining site, whereas dust fallout outside the mining site was clearly lower, and slightly less in 2017 than in the previous year.

The permit limits of air emissions were tightened during 2017. Hydrogen sulphide measurements at the metals production plant fell below the environmental permit limit value. The particulate concentration in ore fine crushing, as well as the particulate and sulphur dioxide concentrations of heat production, were exceeded once during the year. Ore production replicate measurements were, however, below the limit value of 5 milligrammes per cubic metre (mg/m3).

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