Useful metals come from Useful metals come from rocks and minerals in the rocks and minerals in the

Earth’s crust.Earth’s crust.

Metals-1-1Image: G. Plumlee, USGS

Mining of metal-bearing Mining of metal-bearing rocks also requires removing rocks also requires removing

less valuable rocks - waste less valuable rocks - waste rocks.rocks.

Metals-1-2Image: Kennecott Utah Copper Co.

Separating metal-Separating metal-bearing minerals from bearing minerals from others produces waste others produces waste

called “tailings”.called “tailings”.

Metals-1-3Image: Kennecott Utah Copper Co.

Environmentally sound Environmentally sound disposal of waste rock and disposal of waste rock and

tailings is needed to protect tailings is needed to protect soil and water resources.soil and water resources.

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Before

AfterImages: Gold Institute, Echo Bay Mines; S. Warren

Environmentally sound Environmentally sound disposal of waste rock and disposal of waste rock and tailings commonly uses soil tailings commonly uses soil covers that prevent erosion covers that prevent erosion and development of acidic and development of acidic

waters (acid rock drainage).waters (acid rock drainage).Revegetated Pile Surface

Compacted consolidated wasterock

Soil Growth Medium

Uncompacted Lime - amended wasterock

12”

12”

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Image: Kennecott Utah Copper Co., DeAtley Design

In some cases, covering In some cases, covering tailings with water prevents tailings with water prevents

acid rock drainage and acid rock drainage and creates valuable habitat.creates valuable habitat.

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Before AfterImages: Kennecott Utah Copper Co.

Historically, mineral processing to Historically, mineral processing to recover metals from minerals recover metals from minerals

emitted large amounts of harmful emitted large amounts of harmful gases and particles to the gases and particles to the

atmosphere.atmosphere.

Metals-1-7Image: Atlantic Richfield Company

Modern facilities to recover metals from minerals use new technology that reduces emissions below those permitted by regulatory agencies.

Acid Mist – 151 Acid Mist – 48 Particulates – 728 Particulates – 400 SO2 - 20,050 SO2 – 982

Discharges at Kennecott smelter in Utah.

Comparison units in metric tonnes.

1992 Modernized (Permitted) Smelter

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Image: Kennecott Utah Copper Co., DeAtley Design

Metals we need can be Metals we need can be provided in provided in

environmentally sound environmentally sound ways.ways.

Metals-1-9Image: Digital Vision