Extraction of Uranium & the environmental impacts 92 238.03 The extraction of uranium and the environmental impacts caused by its extraction!

How? Open pit Underground In-situ leaching (ISL) Uranium resources can be extracted from the ground in three ways: Open pit Underground In-situ leaching (ISL) Uranium resources can be extracted from the ground in three ways: The three methods used for extraction are open pit, underground and in-situ leaching which is also known as ISL.

Open Pit For shallow ore bodies (<400ft) Involves removal of overburden A lot of waste rock removed Greatest environmental impacts (<400ft) Open pit mining, also known as strip mining, is the removal of uneconomic rock to reach the ore beneath it. If the uranium ore lies close to the surface (normally less than 400ft) then it’s usually extracted using an open pit mine. This involves the removal of the overburden (overlying rock)and a lot of waste rock. Open pit mines also have the greatest environmental impacts.

Case Study Jackpile Mine on Laguna Pueblo was once the largest! ≈ 7,868 acres ≈ 25 million tons extracted The Jackpile Mine on Laguna Pueblo was once the worlds largest open pit uranium mine. The mine was approximately 7,868 acres in size. During the 29 years of activity, approximately 25 million tons of uranium were extracted from the mine.

Underground For deeper ore bodies Involves access shafts and tunnels Less waste rock removed Less environmental impacts Where the ore bodies are deeper, underground mining is usually used, involving construction of access shafts and tunnels but with less waste rock removed and less environmental impact compared to open pit mining.

Grade control How is it achieved? Measure radioactivity using a radiometric device Device detects decay products of uranium Grade control is usually achieved by measuring radioactivity using a radiometric device. The device detects associated radioactive minerals which are decay products of the uranium, rather than the uranium itself.

In-situ Leaching For ore bodies which lie in groundwater Groundwater circulated through underground aquifer containing uranium Leaching solution dissolves uranium Dissolved uranium pumped out and recovered as a precipitate Least environmental impacts Some ore bodies lie in groundwater in porous unconsolidated material (such as gravel or sand). These are accessed by dissolving the uranium and pumping it out. This method is known as in-situ leach mining. Weakly acidified groundwater with a lot of oxygen in it is circulated through an enclosed underground aquifer which holds the uranium ore in loose unconsolidated material. The leaching solution dissolves the uranium before being pumped to the surface treatment plant where the uranium is recovered as a precipitate. ISL mining means that uranium minerals are extracted without any major ground disturbance. Therefore where appropriate it is certainly the mining method with the least environmental impacts.