Desert similar. They occur in regions where large temperature differences occur between sea and land. Moist warm air rises over the land, deposits its water content and circulates back to sea. Further inland, areas receive very little precipitation. The Thar Desert near the India/Pakistan border is of this type. In some parts of the world, deserts are created by a rain shadow effect. Orographic lift occurs as air masses rise to pass over high ground. In the process they cool and lose much of their moisture by precipitation on the windward slope of the mountain range. When they descend on the
Thar coalfield over more than 9,000 km. comprise around 175 billion tonnes sufficient to meet the country's fuel requirements for centuries. Sindh Engro Coal Mining Company mine's coal from the field. The Thar coalfield is located approximately between Latitudes 24°15'N and 25°45'N and Longitudes 69° 45'E and 70° 45'E in the southern part of Sindh Province in the Survey of Pakistan topo-sheet Nos. 40 L/2,5 and 6. Based on available infrastructure and favourable geology, the Geological Survey of Pakistan selected four blocks near Islamkot for exploration and assessment of coal resources. The blocks with names, area and coordinates are given in Table-1:¬