JNTU B.Tech II DEVELOPMENT OF MINERAL DEPOSITS Previous Question Paper (September - 2021 - R18)

Surface mining is employed for mineral deposits located at or near the surface, involving the removal of overburden to extract ore. Underground mining is used for deeper deposits, requiring access via shafts, adits, or inclines to reach the ore body while leaving the overlying strata largely intact.

Key distinctions include:

• Methodology: Surface mining uses open-pit, strip, or quarrying techniques; underground mining utilizes methods like room-and-pillar, block caving, or cut-and-fill.
• Safety and Environment: Surface mining generally offers better ventilation and lower accident rates but causes significant surface disturbance. Underground mining involves higher risks related to roof stability, ventilation, and gas management.
• Cost and Scale: Surface mining typically allows for high-volume, low-cost production with high mechanization. Underground mining is more capital-intensive and selective, often resulting in higher operational costs per tonne.
• Recovery: Surface mining achieves higher recovery rates of the total deposit, whereas underground mining often leaves behind pillars or requires backfilling to maintain structural integrity.

India possesses a diverse and rich mineral resource base distributed across distinct geological belts:

• Peninsular Shield: This region is the primary source of metallic minerals. The Dharwar Craton in Karnataka and the Singhbhum-Odisha-Jharkhand belt are rich in iron ore, manganese, and copper. The Aravalli range in Rajasthan contains lead, zinc, and silver deposits.
• Coal Belts: Major coal deposits are concentrated in the Gondwana basins located along the river valleys of the Damodar, Mahanadi, Son, and Godavari, primarily spanning Jharkhand, West Bengal, Odisha, and Chhattisgarh.
• Tertiary Deposits: These are found in the Himalayan foothills and the northeastern states, containing significant reserves of coal, petroleum, and natural gas.
• Coastal and Sedimentary Basins: The offshore regions, particularly the Mumbai High, are the primary sources of petroleum and natural gas. Coastal areas also host significant deposits of heavy minerals like ilmenite and monazite in beach sands.

The distribution is heavily influenced by the geological age and tectonic history of the Indian plate, with older crystalline rocks hosting metallic ores and sedimentary basins hosting fossil fuels.