Limestone, gypsum and rock salt are among Pakistan’s most important non-metallic minerals. They are widely used, relatively bulky and often processed near the extraction site. Their development illustrates how geology, transport cost, industrial demand and environmental management influence mineral industries.

Limestone

Limestone is widespread and is quarried in the Salt Range, Potwar Plateau, northern Punjab, Khyber Pakhtunkhwa, Sindh and Balochistan. Named examples commonly used in O Level courses include Daud Khel, Wah, Dandot, Rohri, Hyderabad/Thatta areas and deposits near cement-producing districts. Exact lists vary, so the important skill is linking broad location to industrial use.

Its most important use is cement manufacture. It is also used as building stone, road aggregate, in lime, chemicals and as a flux in some metallurgical processes. Because limestone is heavy and low in value per tonne, cement plants benefit from being close to quarries.

Gypsum

Gypsum occurs in parts of the Salt Range, Kohat region, Dera Ghazi Khan area, Sibi and other sedimentary basins. It is used in cement to control setting, in plaster and plasterboard, as a soil conditioner and in some chemical products.

Gypsum is usually obtained by quarrying or shallow mining, crushed and transported to cement or building-material plants. Purity, thickness of the deposit and distance to industry affect its value.

Rock salt

The Salt Range contains famous deposits at Khewra, Warcha and Kalabagh. Rock salt is extracted through underground rooms and pillars so that enough rock is left to support the roof. Salt is crushed, graded and purified according to its final use.

Uses include food, preservation, livestock feed, chemicals, soap, textiles and decorative products. Chemical industries use salt as a raw material for products such as caustic soda and chlorine.

Quarrying and underground extraction

Limestone and gypsum are often worked in open quarries. Overburden is removed, rock is drilled and blasted, broken material is loaded and carried to crushers. Rock salt is commonly mined underground through tunnels and chambers. Ventilation, roof support, drainage and safe transport are essential.

Quarrying is cheaper than deep mining where deposits are near the surface, but it produces visible scars, dust, noise and habitat loss. Underground mining has higher capital and safety costs but causes less direct surface removal.

Industrial location and value addition

Cement factories locate near limestone and gypsum because transporting huge quantities of raw rock is costly. They also need fuel or electricity, water, labour, roads or rail and a large market. Salt-processing plants benefit from proximity to mines but higher-value refined products can be transported farther.

An examination answer on location should combine raw material with at least two other factors; raw material alone rarely explains the complete pattern.