U235 earth dating
Open pit mines require large holes on the surface, larger than the size of the ore deposit, since the walls of the pit must be sloped to prevent collapse.
As a result, the quantity of material that must be removed in order to access the ore may be large.
The splitting of a single U-235 atom can release roughly 200 Me V (million electron volts).
When the uranium atom splits, lots of heat is released, as well as gamma radiation (high-energy photons).
Most of the radioactivity associated with uranium in nature is in fact due to other minerals derived from it by radioactive decay processes, and which are left behind in mining and milling.
There are a number of areas around the world where the concentration of uranium in the ground is sufficiently high that extraction of it for use as nuclear fuel is economically feasible. Both excavation and in situ techniques are used to recover uranium ore. In general, open pit mining is used where deposits are close to the surface and underground mining is used for deep deposits, typically greater than 120 m deep.
It is, for example, found in concentrations of about four parts per million (ppm) in granite, which makes up 60% of the Earth's crust.
In fertilisers, uranium concentration can be as high as 400 ppm (0.04%), and some coal deposits contain uranium at concentrations greater than 100 ppm (0.01%).
The nuclear fuel cycle starts with the mining of uranium and ends with the disposal of nuclear waste.The difference in weight becomes energy and can be calculated using the equation E=mc2.In order for uranium to be suitable for power production in nuclear plants, it has to be enriched so that it contains at least three percent of U-235.It is about 500 times more abundant than gold and about as common as tin.It is present in most rocks and soils as well as in many rivers and in sea water.