For the production of electricity 4.4 M tons of coal per year is needed. 500 millions kWh is heat production and 4x109 kWh is electricity production per year.
The coal power plant is connected to the active mining area (lignite mine) near the town Velenje (about 20 000 inhabitants). The tailing covers an area of few km2. Three ponds are situated on the area of tailings. The nearby river is not directly connected with the tailings but indirectly through groundwater.
There is a risk for contamination of air and groundwater. People are living a few 100 m away from the area which is a popular recreation area (swimming in the summer and skating in the winter).
The tailing covers 80 ha with about 700000 tons coal ash per year, 60000 tons slag and 350000 tons gypsum per year.

The ecological monitoring programme for solid waste disposal (fly ash and bottom ash, dry and wet residual products from the flue gas de-sulphurisation plant) started in 1996.
The programme includes surface water (the Lake Velenje, its outflowing water - the river Paka) and underground water, water sediments, air suspended particulate, dry and wet deposition of particles, soil and deposited materials, vegetation and food. The results show a limited local environmental impact. The previous high alkalinity of water from the Lake Velenje decreased in recent years due to operation of a new closed water cycle system.
Radiation monitoring around the coal power plant, consisting in measurements of the most important pathways for dose evaluation for civil population, external dose, inhalation of air and ingestion shows that the biggest contributor to the dose is radon with its short-lived daughters. The difference between radon concentration on the depository and in the living area is 5-7 Bq/m3.

The closed coal mine area near Kocevje
This closed mine area is located near the town Kocevje (7 000-10 000 people, SE-Slovenia). It was an open coal mine with brown coal exploited up to 70 m deep. After the closure, the open mine was filled with groundwater and now it is a pond (ca 200 m x 300 m). People are living on the tailings. Fly ash was used for covering areas around houses and also as building material. The main contamination is groundwater and re-suspension. The highest dose is from radon and external radiation.