Radioactive mineral deposits

Nuclear radiation has been used for borehole and well analysis, generally referred to as logging. Detecting and measuring the radiation permits an evaluation of the properties of a formation surrounding the borehole and therefore, is used for locating and extracting, for example, radioactive mineral deposits and petroleum. 

Nuclear-physical methods ai e the basic ones in controlling environmental pollution which results from nucleai -power complexes and power plants work. Oil and gas production leads to the extraction of radio nuclides of natural origin in considerable amounts, which later spread from oil-slimes and water wastes in the neighborhoods of oil and gas producing entei prises. Similaidy, toxic and radioactive elements can pollute environment in case of mineral deposits extraction. 

Although the nucleus of the uranium atom is relatively stable, it is radioactive, and will remain that way for many years. The half-life of U-238 is over 4.5 billion years the half-life of U-235 is over 700 million years. (Half-life refers to the amount of time it takes for one half of the radioactive material to undergo radioactive decay, turning into a more stable atom.) Because of uranium radiation, and to a lesser extent other radioactive elements such as radium and radon, uranium mineral deposits emit a finite quantity of radiation that require precautions to protect workers at the mining site. Gamma radiation is the... 

Radiation exposure from both natural and human sources varies widely. Background radiation depends on the local geology and elevation. Areas where radioactive rocks are located close to the surface or where mining has exposed mineral deposits have higher background levels. Higher... 

CaS04 2 H2O) in plasters to decorate their tombs. These two alkaline earths are among the most abundant elements in the Earth s crust (calcium is fifth and magnesium sixth, by mass), and they occur in a wide variety of minerals. Strontium and barium are less abundant but like magnesium and calcium, they commonly occur as sulfates and carbonates in their mineral deposits. Beryllium is fifth in abundance of the alkaline earths and is obtained primarily from the mineral beryl, 863 2(8103)6. All radium isotopes are radioactive (the longest lived isotope is Ra, with a half-life of 1600 years). Pierre and Marie Curie first isolated radium from the uranium ore pitchblende in 1898. Physical properties of the alkaline earths are given in Table 8.4. 

The potential mineral resources of the Transantarctic Mountains, including metallic and radioactive minerals as well as coal in the Beacon Supergroup, were discussed in Section 11.5. We now turn to the Dufek intrusion which contains several important metals Iron, titanium, chromium, vanadium, copper, cobalt, nickel, and members of the platinum group of elements. Although the Dufek intrusion is an attractive target for mineral exploration. Ford (1990) emphasized that no minable deposits of any kind are currently known to exist there. The scientific merits of drilling the Dufek intrusion were discussed in 1979 by the Committee on Eneigy and Natural Resources of the US. Senate, but these discussions were terminated becanse of concern about contamination of the environment. 

The 163-N facility (Figure 3-17) produced high-quality, demineralized makeup water from filtered river water for the major coolant systems of the N Reactor. Demineralized water has virtually all dissolved and suspended matter removed by ion exchange. Demineralized water was used to prevent mineral deposits that would foul piping systems and to limit the generation of radioactive waste through neutron activation of dissolved and suspended matter (DOE-RL 1990). 

The equations governing the age of secondary carbonate deposits stated above assume that all °Th or Pa present in the mineral is formed in situ by radioactive decay of co-precipitated U. Thorium and Pa content at time of formation can often be considered to be negligible in the pure authigenic phase of calcite or aragonite... 

The element revealed itself through spectacular violet-colored flames and several red spectral lines. The metal melts at 38 °C, is very soft, and extremely reactive (burns in air and reacts violently with water). Rubidium is stored under mineral oil. It is suitable as a scavenger (oxygen capture) in vacuum tubes, where it is deposited on the glass as a mirror. It can also be found in photocells and phosphors for screens (for example, for air-traffic controllers. Not physiologically important. The radioactive rubidium-87 is useful for age determination in geochronology (half-life ca. 50 billion years). 

Similar equations can be written for Pb and Pb using their appropriate radioactive parents and decay constants. If t = 0 is taken to represent the time of the formation of the Earth s crust, then these three equations describe the trajectory of the isotopic composition of terrestrial lead from that time. If T is the time elapsed since the formation of the Earth, (i.e., the age of the Earth), and tm is the time before present at which the lead minerals were formed, then, using the assumptions of the Holmes Houtermans model given above, the isotopic composition of a common lead deposit formed tm years ago is given as follows ... 

Large thorium deposits have heen found in many parts of the world. It occurs in minerals thorite, ThSi04, and thorianite, Th02"U02. Thorium also is found in mineral monazite which contains between 3 to 9% Th02. Th02 is the principal source of commercial thorium. Abundance of thorium in earth s crust is estimated at about 9.6 mg/kg. Thorium and uranium are believed to have contributed much of the internal heat of the earth due to their radioactive emanations since earth s formation. 

De Putter, T., Andre, L., Bernard, A., Dupuis, C., Jedwab, J., Nicaise, D. Perruchot, A. 2002. Trace element (Th, U, Pb, REE) behaviour in a cryptokarstic halloysite and kaolinite deposit from Southern Belgium importance of accessory mineral formation for radioactive pollutant trapping. Applied Geochemistry, 17, 1313-1328. 

Radium, similarly to calcium, deposits in bone within those areas where new bone mineral is being formed and also on all bone surfaces. Radium remains in those areas of new bone formation, but the radium deposits on bone surfaces eventually move into the depths of compact bone as new bone matrix is deposited on top of them. In this deposition process, short-lived radium-224 rapidly decays, leaving no radioactivity within bone whereas, long-lived radium-226 remains in the skeleton indefinitely (Rowland 1966). Mays et al. (1975) have demonstrated that the radon to radium ratio in bone increased with time after injection in beagles. 

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