They decide to investigate, both to pursue the mystery of the symbol and because the planet contains useful minerals.

We surveyed it when we first came up here, and though there were a lot of useful minerals we decided against prospecting further.

They have plenty of power, there may be useful minerals in the area - and we know that the Chinese are the experts on synthetic-food production.

Most of the useful minerals that could be mined by primitive means were long since exhausted.

As I said, we've sent expeditions everywhere to collect and classify all the rocks they can, in the hope of finding useful minerals.

Owing to its rarity, huttonite is not an industrially useful mineral.

After 1949 geological exploration discovered deposits of more than 130 useful minerals.

Geological surveying provides the location of useful minerals and such information could be used to benefit the country's mining industry.

They are miners who especially like to dig up "sun's blood" (gold) and other useful and beautiful minerals.

When they died, their carcasses were not corrupt, and contained useful minerals in small but quantifiable amounts.