Chapter 16

Crushed ore is melted at high temperatures to separate impurities from molten metal during

• open-pit mining

• hydrothermal solution mining

• smelting

• dredging

Stream placers often occur

• in empty riverbeds

• at bends in rivers

• where rivers meet lakes

• where sediments are discharged

Which of the following would not be considered an aggregate?

• sea glass

• sand

• gravel

• crushed rock

The process by which land sinks with little to no horizontal movement is known as

• compounding

• quarrying

• reclamation

• subsidence

Minerals are arranged in a regular, repeating geometric pattern of

• atoms

• aggregates

• metals

• evaporites

Which of the following is NOT a method of subsurface mining?

• room-and-pillar mining

• long wall mining

• solution mining

• open-pit mining

From whom must mining companies obtain permits before mining a site?

• state and federal agencies

• federal agencies only

• local government only

• a bonding company

Gangue minerals

• are valued for thier rarity and durability

• have no commercial value

• are the most difficult of all materials to mine

• are native elements

Which of the following is NOT one of the ways that ore minerals may form?

• flooding of empty stream beds and rivers

• cooling of magma

• circulation of hydrothermal solutions through rocks

• evaporation of water that contains salts

Reclamation is the process of

• removing coal from a subsurface seam

• extracting ore minerals from gangue minerals

• returning land to its original, or better condition after mining operations have been completed

• protecting the habitats of local wildlife