JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II Year MINING GEOLOGY Previous Question Paper (October - 2020 - R16)

Bauxite is a residual sedimentary rock and the primary ore of aluminum. Its physical properties include a dull, earthy luster, a hardness ranging from 1 to 3 on the Mohs scale, and a specific gravity between 2.0 and 2.5. It typically appears in pisolitic or oolitic structures with colors ranging from reddish-brown to white or gray. Chemically, it is a heterogeneous mixture of aluminum hydroxide minerals, primarily gibbsite (Al(OH)3), boehmite (γ-AlO(OH)), and diaspore (α-AlO(OH)), often associated with impurities like iron oxides, silica, and clay minerals.

Talc is a hydrous magnesium silicate mineral known for its extreme softness. Its physical properties define it as the reference mineral for 1 on the Mohs scale of hardness; it has a greasy or soapy feel, a pearly to waxy luster, and a white to pale green streak. It is translucent to opaque and typically occurs in foliated or massive habits. Chemically, it is represented by the formula Mg3Si4O10(OH)2. It is chemically inert, insoluble in water, and resistant to acids, which makes it highly valuable for industrial applications.