Human Interaction with the Rock Cycle Tara Lead and Zinc Mines

Learning Outcome  Identify the ways humans use rocks in Tara Mines  Discuss the impact this has on the Rock Cycle

Mining in Ireland Important economic activity Employs 6000 people Generates over 1 billion euro annually

Lead Valuable Widely used 60% of all lead is used in lead acid batteries Has many other uses; – Plumbing – X-ray gowns – Ammunition – TV & Computer screens (blocks radiation)

Zinc Galvanising steel (prevents rust) Zinc dust & compounds used in; – Cosmetics – Plastics – Paints – Ink

Tara Mines Navan, Co Meath

Formation of Lead & Zinc Rock containing metal is called ore Carboniferous limestone Formation of ore linked to movement of groundwater through the rock Seawater seeped into the rock This was heated by geothermal energy from inside earth As the hot seawater (brine) moved through the planes and joints, it dissolved small amounts of lead and zinc out of the rocks The rich layers of ores within the rocks are called veins

Human Interaction with Rock Cycle in Tara Construct shaft mines Extract ore Disposal of waste products Transport systems

General Info Shaft Mine Europes largest zinc mine 5 th largest zinc mine in the world Uses state of the art, remote control technology and computerised systems Local economy in Navan has benefitted financially

Employment 700 Jobs – Chemists – Environmental Scientists – Miners – Geologists

Mining in Tara Output transported to Norway, Finland & other European countries Lead and zinc ores formed in faulted limestone in Navan, over 350 million years ago Lie 50 – 900 metres below the surface

Extraction Stope and Pillar Large areas (stopes) blasted out and pillars left standing to support them Modern computerised machinery used to bring the ore to the surface

On the Surface Rock crushed into powder Chemically treated Dried to form metal concentrate Then transported to Dublin Port

Further process details Water used is recirculated and reused Sediment is extracted and stored Backfill may be needed in the stopes, cement and water pumped through the boreholes

Process Mill Operates continously 12 hour shifts Highly computerised On-site laboratory –analysis tests on rock samples

Environmental Protection Landscaping to reduce visual impact Wetland areas to treat water Sheep grazing areas Noise and Dust levels constantly monitored Regular reports to the EPA

Spin-Off Effects For every one job in Tara, three indirect jobs are supported. – Eg; Caterers, Accountants, Truck Drivers, Safety Consultants, Metallurgists

Future 2009; Threatened with closure – Demand for zinc to galvanise car bodies fell However continued demand for zinc from China and India Mine life extends past 2015

Keywords Mining Ore Extraction System Environmental Protection

Exam Question ‘People interact with the rock cycle in various ways.’ Examine this statement using an example you have studied.