1-3 Formation and Mining of MineralsObjectives:

1. Describe the environments in which minerals form.

2. Compare and contrast the different types of mining.

Formation of Minerals

• The environment determines minerals properties.

• Types:

evaporating saltwater, limestones, metamorphism, hot-water solution, pegmatites, plutons

Evaporating Saltwater Minerals

• Form when a body of salt water dries up.

• Halite• Gypsum

Limestone Minerals

• Form when surface and ground water carry dissolved minerals into lakes and seas.

• Calcite• Dolomite

Metamorphic Minerals

• Form when heat and pressure changes the structure of existing minerals

• Garnet• Magnetite

Hot-water Solution Minerals

• Form when water heated by magma dissolves metals and other minerals into a solution. These crystallize when the water evaporates.

• Gold• Sulfur

Pegmatite Minerals

• Tear shaped bodies of magma take a long time to cool – therefore they form large crystals.

• Tourmaline• Topaz

Pluton Minerals

• Magma that is close to the surface, but far enough underground that it is well insulated and cools slowly.

• Quartz• Mica

Mining

• Ore – a mineral deposit large enough to be mined for profit.

Surface Mining

• The removal of minerals or other materials at or near Earth’s surface.

• Open pit mines• Quarries• Strip mines• Copper and aluminum

are mined this way.

Deep Mining

• The removal of minerals or other materials from deep within the earth.

• Diamonds and coal are commonly mined this way.

Value of Minerals

• Gems – minerals that are very rare and attractive. They are admired for their beauty rather than their usefulness.

Metals – from mineral ores – chalcopyrite (copper), galena (lead), beryl (beryllium), chromite (chromium)

Responsible Mining

• Reclamation – returns a mined area to its natural state after mining is complete. It has been required since the 1970’s and has improved on the habitat of many animals and plants.