Oil pastel an almost impasto effect. Once applied to a surface, the oil pastel pigment can be manipulated with a brush moistened in white spirit, turpentine, linseed oil, or another type of vegetable oil or solvent. Alternatively, the drawing surface can be oiled before drawing or the pastel itself can be dipped in oil. Some of these solvents pose serious health concerns. Oil pastels are considered a fast medium because they are easy to paint with and convenient to carry; for this reason they are often used for sketching, but can also be used for sustained works. Because oil pastels never dry
Narva Oil Plant from the power plants and the separate subsidiary of Eesti Energia was established. The retorting plant consists of two modified Galoter type solid heat carrier retorts (Enefit retort)—both processing 125 tonnes per hour of oil shale. Main products are fuel grade shale oil, raw material for bitumen and antiseptics. The designed annual capacity of the plant is 220,000 tons of shale oil and 60 million cubic meters of retort gas. In May 2009, Eesti Energia announced that it plans to build a new shale oil plant adjacent to the existing plant with processing capacity of 2.26 million tonnes of oil