Stanari lignite has been proven to have low ash and sulphur content and an acceptable heating value for lignites.  Average Stanari lignite quality is given in the following table:

Exploration of coal reserves at the Stanari basin has been done on several occasions, since 1954. The classified Stanari basin lignite reserves according to JORC Code (2004) are as follows:

Area	Proved Reserves (Mt)	Measured Resources (Mt)	Indicated Resources (Mt)
Raškovac field	50.68	15.33	1.29
Ostružnja field	57.27	-	-
Total	107.95	15.33	1.29

The average stripping ratio for the Stanari basin is 4.4 m3/t. The overburden on both Raškovac and Ostružnja coalfields consists of mainly sand and clay materials.

In the Raškovac Coalfield the overburden sequence varies from 25-40 m in thickness. The lignite is constant in thickness, ranging between 10-15m throughout with two interburden layers of soft clay.  The average stripping ratio on Raškovac Coalfield is 2.1 m3/t.

In the Ostružnja Coalfield, the overburden sequence thickens from west to east. The thickness is between 20m and 40m in the west and central parts of the prospective area, and between 50m and 60m in the eastern part.

In the western part of Ostružnja the lignite layer thickness ranges from 5-13 m whereas further east the lignite thickness is 5-8 meters. As in the Raškovac coalfield, the lignite layer is divided by two soft clay interburden layers.

The average stripping ratio on Ostružnja Coalfield is 5.3 m3/t.