Mineral resources are non-renewable. Every effort should be made to mine both high-and low-grade ores and utilise those precious resources fully, scientists and mineral experts who participated at a recently held three-day symposium here recommended. “At every mine site, the low-grade ores and minerals, which are many times more than the high-grade ones, have to be upgraded and the wastes should be utilised for backfilling the mined areas or other purposes,” they said.