Lecture 19: Mining

industrial minerals

a subclass of ore deposits

solid material extracted from ground for purposes other than energy or metal production

Aggregate

broken or unconsolidated rock for foundations

Arklow quarry - dolerite

Cement

mix of limestone with shale/clay heated in kiln, ground to powder

Concrete

mix of cement and aggregate

releases CO2 from limestone → responsible for 8% of anthropogenic CO2 emissions

Dimension stone

large slabs of rock

Plaster

gypsum and some additives

gypsum

powdered partially dehydrated by heating

mixed with water into paste coated in brown paper = plasterboard

gypsum quarry, Co. Monaghan

Ceramics

firing clay

bricks, pottery, porcelain

heating of soft clay => physical and chemical changes → water lost and grains reconstruct closer together

glass

special ceramic

made of quartz, sodium carbonate, calcium , magnesium, and aluminium oxidesWh

What does the sodium in glass do?

reduced melting point

What do the oxides in glass do?

durability

Environmental problems with mining

mainly from ore minerals

• water pollution

• air pollution

• use of water

• use of energy

Environmental problems at historical mining sites:

Tynagh, Galway & Silvermines, Tipperary 

Zinc and lead mines

• soil heaps that have toxic levels of metals

  • Groundwater contamination

  • Windblow dust

• No remediations until recently

  • hydropump storage at Silvermines

Environmental problems at historical mining sites:

Avoca, Wicklow

underground sulphides of copper and lea mining in 19thC

• acidic water runoff

  • effects on wildlife

Environmental problems at historical mining sites:

Smelting at Norisk, Siberia

nickel and copper smelting

• acid air pollution

Environmental problems at mining sites:

Utah, USA & Tara Mines, Navan

negligible pollution from mining and smelting

Ktone

thousands of tonnes of oil equivalent energy

Energy use of mining and quarrying sector

150ktoe

MtCO₂

Millions of tonnes of CO₂

CO₂ emissions of mining and quarrying sector

0.6 MtCO₂

most is from electricity which can be converted to green

Energy relative to gross value added of Mining and quarrying

12.3%

Global green house gas emissions of:

• iron

• copper

• gold

Iron → hauling and loading

Copper → crushing and grinding

Gold → high emissions despite small amount produced