Additional Blogs by Members
cancel
Turn on suggestions
Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.
Showing results for 
Search instead for 
Did you mean: 

Uranium Mining

pratik_soni
Participant
‎08-03-2013 1:24 PM
0 Kudos

About Uranium

Uranium is a silvery-white metal, roughly 70% denser than lead and is the only naturally-occurring fissile element on earth. Uranium is more common than tin, about 40 times more common than silver and 500 times more common than gold. It’s found in very low concentrations almost everywhere on earth in soil, rocks, water and even in your own back yard.

Uses of Uranium

  • Nuclear Fuel: Nuclear power provides safe, clean, reliable, and affordable base load electricity and is an important part of the world’s energy mix which currently consists of 13.4% of total fuel consumption. When used as nuclear fuel Uranium is efficient source of energy for generating electricity throughout the world.

  • Other uses:
    • In Medical as Radiotherapy for treatment of cancer and other diseases.
    • For desalination plants, used to make clean drinkable water from seawater.
    • Industrial radiography, gauging applications and mineral analysis.

Nuclear Fuel value chain

There are many steps in the journey from discovery of uranium to its use in generating electricity. The transformation of uranium ore to nuclear fuel, and the reprocessing and long-term management of spent-fuel, is described as the nuclear fuel cycle.

  1. Mining & Milling to produce uranium concentrate known as yellowcake
  2. Refining & Conversion of the concentrated uranium into either uranium dioxide (UO2) for heavy water reactors or gaseous uranium hexafluoride (UF6) for light water reactors
  3. Enrichment, which increases the proportion of the rarer 'fissile' form of uranium, U235, which is the essential component of nuclear fuel
  4. Fuel Manufacture, where the uranium is manufactured into fuel pellets
  5. Electricity Generation, where nuclear fuel is loaded into a reactor and nuclear reactions generate electricity.
  6. Spent Fuel Management, spent nuclear fuel is safely stored as it cools, optionally reprocessed or moved into secure long-term storage.

Uranium Mining

Uranium mining is the process of extraction of uranium ore from the ground. There are different methods used for mining uranium of which In situ leaching method is getting more popular because in situ recovery (ISR) process involves minimal surface environmental disturbance and does not produce waste rock or tailings.

See the video below of In situ mining process.

Milling Process:

After mining uranium ores, they are normally processed by grinding the ore materials to a uniform particle size and then treating the ore to extract the uranium by chemical leaching. The milling process commonly yields dry powder-form material consisting of natural uranium, "yellowcake," which is sold on the uranium market as U3O8.

See the video of how Milling process works.

World Uranium Mining Production (Updated July 2013)

  • About 64 percent of the world's production of uranium from mines is from Kazakhstan, Canada and Australia.
  • An increasing proportion of uranium, now 45%, is produced by in situ leaching.
  • After a decade of falling mine production to 1993, output of uranium has generally risen since then and now meets 86% of demand for power generation.

Occupational Safety in Uranium Mining

The International Commission for Radiological Protection (ICRP) has established recommended standards of protection (both for members of the public and radiation workers) based on three basic principles:

  • Justification: No practice involving exposure to radiation should be adopted unless it produces a net benefit to those exposed or to society generally.
  • Optimization. Radiation doses and risks should be kept as low as reasonably achievable (ALARA),economic and social factors being taken into account.
  • Limitation. The exposure of individuals should be subject to dose or risk limits above which the radiation risk would be deemed unacceptable.

These principles apply to the potential for accidental exposures as well as predictable normal exposures.

In Australia, mining operations are undertaken under the country's Code of Practice and Safety Guide for Radiation Protection and Radioactive Waste Management in Mining and Mineral Processing, administered by state governments (and applying also to mineral sands operations). In Canada, the Canadian Nuclear Safety Commission regulations apply. In other countries there are similar arrangements to set health standards for gamma radiation and radon gas exposure, as well as for ingestion and inhalation of radioactive materials. Standards apply to both workers' and public health.

A number of precautions are taken at a uranium mine to protect the health of workers:

  • Dust is controlled, so as to minimize inhalation of gamma- or alpha-emitting minerals. In practice dust is the main source of radiation exposure in an open cut uranium mine and in the mill area.
  • Radiation exposure of workers in the mine, plant and tailings areas are limited.
  • Radon daughter exposure is minimal in an open cut mine because there is sufficient natural ventilation to remove the radon gas.
  • Strict hygiene standards are imposed on workers handling the uranium oxide concentrate. If it is ingested it has a chemical toxicity similar to that of lead oxide (Both lead and uranium are toxic and affect the kidney. The body progressively eliminates most Pb or U, via the urine). In effect, the same precautions are taken as in a lead smelter, with use of respiratory protection in particular areas identified by air monitoring.

References

Popular Blog Posts