Why do we need to conserve mineral resources?
We need to conserve mineral resources because they are finite and non-renewable. The total volume of workable mineral deposits is an insignificant fraction, i.e., only one per cent of the earth's crust. We are rapidly consuming mineral resources that required millions of years to be created and concentrated.
The geological processes of mineral formation are so slow that the rates of replenishment are infinitely small in comparison to the present rates of consumption. Rich mineral deposits are our country's extremely valuable but short-lived possessions.
Continued extraction of ores leads to increasing costs as mineral extraction comes from greater depths along with decrease in quality. Since industry and agriculture have a strong dependence on mineral deposits, we must use them in a planned and sustainable manner through improved technologies, recycling of metals, and using scrap metals and substitutes.
Explanation
This answer addresses all key reasons mentioned in the NCERT textbook context: (1) Minerals are finite and non-renewable with only 1% of earth's crust being workable deposits, (2) They take millions of years to form and replenishment rates are negligible compared to consumption, (3) They are valuable but short-lived possessions, (4) Continued extraction becomes costlier with depth and quality reduction, and (5) Industry and agriculture depend heavily on them. The answer also briefly mentions conservation methods like recycling and using substitutes as stated in the context.