Block 12: Metal Mine Remediaiton

Question 1

How has mining changed in Britain throughout history?

Answer 1

Bronze Age: pit mining
Roman Britain: hush mining (water flows revealed veins)
Medieval Era: stamp mill mining (water mills power massive hammers)
18th Century: shaft & adit mining
20th Century: mapped industrial expeditions

Question 2

How is acidity generated from mines?

Answer 2

Through oxidative weathering of pyrite, which releases sulphuric acid

Question 3

How are metal ions generated by mines?

Answer 3

Through sulphide weathering

Question 4

Who bears responsibility for metal mine pollution?

Answer 4

No one was held responsible up until 2000, so the Mining Remediation Authority is accountable for clean up
The Water Framework Directive classifies threat levels

Question 5

What are the EQS standards for lead, zinc, & cadmium

Answer 5

Pb: 1.2 µg/L
Zn: 10.9 µg/L
Cd: 0.08 µg/L

Question 6

How does ochre precipitation remove contaminants from waters?

Answer 6

Oxidation in aerated environments converts soluble ferrous iron into insoluble ferric iron, which precipitates out as ochre. Oxidation can also occur in alkaline environments generated by calcite weathering

Question 7

How do vertical flow ponds remove toxic metals?

Answer 7

Discharge filters through reducing compost environments

Question 8

How does lime dosing adjust pH?

Answer 8

Acidic drainage is mixed with lime slurry, which neutralises the H+ concentration

Question 9

What is electrocoagulation & how does it work?

Answer 9

A sacrificial anode releases soluble anions to combine with the contaminant, producing a precipitate that will coagulate into larger particles that can be removed as slush