In mining, overburden (also called waste or spoil) is the material that lies above an area that lends itself to economical exploitation, such as the rock, soil, and ecosystem that lies above a coal seam or ore body. In many mineral industries, like coal industry, in open cast mines, coal can be extracted only after removing layers of soil, stone etc. This soil and stone etc is known as over burden. The removal of this overburden is known as “Over burden Removal” (OBR) and involves heavy cost.
OBR is an important performance parameter as it exposes the coal seam for future production at short notice.
Stripping activity – It is the activity of overburden removal that benefits the identified component of an ore to be mined by the entity.
Standard stripping ratio - the ratio of “overbudern (OB) to be removed” to “the mineral to be produced” during the whole project life. Suppose in an opencast mine, 20 lakh CuM OB will be removed during the life time (suppose 15 years) against the production of 10 lakh Te of coal, the standard stripping ratio will be 2.1