Download How Minerals Are Mined and Processed

Page 200-201
 Small amounts of different minerals are found in most rocks
 Minerals can be found in large amounts (high concentrations) or
deposits. When minerals are found in deposits it allows minerals to be
mined and can be profitable
 Rock that contains a valuable mineral is called ore
o High-grade ore contains rich concentrations of a mineral making
it the most profitable to mine
Searching for Deposits
 Some geologists spend their whole life searching for valuable minerals
in which to mine
 Geologists study the Earth’s crust to be able to find new minerals
 Once a deposit has been found the process becomes complicated as it
is often deep underground, being trapped in hard rock
 The miner must decide whether strip mining or underground mining
would be best to extract the mineral
o Strip mining – often used when a mineral deposit is discovered
near the surface. The top layer of soil and rock, called
overburden is removed until the ore is exposed. The ore is then
dug out using large machinery. The overburden may not be
returned after the ore has been removed.
o Underground Mining – Used when the mineral is located deep
underground, and mining directly from the surface is too
expensive. A shaft is dug down into the Earth. Large drills
break up the ore; railcars haul the ore to the shaft. The ore is
then crushed and raised to the surface in cages. This process is
called milling The overburden may be shaped and covered with
topsoil, leaving space for plants to be planted.
Processing the Ore
 All types of ore must be processed to separate unwanted rock from
the mineral
 These process includes using large amounts of water and chemicals
 Liquid wastes are placed in tailings pond – these ponds are very toxic
and measures must be taken to ensure they do not leak
When to Close a Mine
 If the value of the mineral is greater then the expense of extracting
the mineral then the mine will close
 When high-grade ore runs out they will close the mine as low-grade
ore is not profitable to mine
 Expensive to close- mine needs to be returned as closely as possible to
its natural state
Read pp. 200, 201, 204
pp. 201 # 1, 2, 3, 4, 5, 6
Outcome: used for enrichment