Why are natural resources not evenly distributed around the surface?

[Hivoyer]

Is there an exact reason for the non-uniformness or is it all just random?I mean in the early stages of Earth's development when It was still hot, shouldn't all types of substances have spread more or less evenly?

 

[Gannet]

Simply Geomorphology from erosion (Appalachians used to be higher than the Rockies but were eroded away creating the Atlantic Coastal Plain; Glaciers scoured the Earth surface, precipitation creating runoff into rivers which move sediment from their mountain headwaters and distribute along it way to finally the ocean. Therefore, in a nutshell it is completely random in nature.

 

[SteamKing]

You don't want stuff distributed too evenly.

The more evenly a substance is spread, the harder and costlier it is to collect. The oceans, for example, contain many tons of all different kinds of minerals dissolved in the water, even gold and silver. However, because everything is dissolved and spread throughout the oceans, it is uneconomical, if not impossible, to extract these minerals.

 

[256bits]

You will have to do some investigative research of each mineral to find out how it comes to be that "concentrated" deposits can be found for each.

I googled geological formation of uranium and this site gives a general description of some processes.
http://www.physics.ohio-state.edu/~wilkins/energy/Companion/E19.4.pdf.xpdf

Bear in mind that concentrated does not mean that that the ore or mineral is there ready to be scooped up in great quantities or mined with little difficulty, although in xome cases that is possible such as with salt mining. Potash mining for example in Saskatchewan, Canada removes the pure substance from a layer several thousand feet below the surface. The layer can be a few feet thick or a few hundred. Of course they will mine on the thicker parts of the layer where it is most pure.

A gold mine on the other hand may produce tailings of several tons to obtain just a single ounce of gold. But that can vary - you might be lucky enough to hit lucky payday if you ever see a thin seam of gold layered between undisturbed sedimentary layers of rock.

Oil and other energy resources are deposits from organisms living several millions years ago and sedimentary layers have built up over top from back then to now, so digging or drilling down is needed.

Pearls form from mollusks of which the oyster is the preferred find.

Other gemstones form by mostly some sort of chemical action. Diamonds, for example, need high heat and pressure for formation and that means way below the Earth's surface. A good place to look then might be around an ancient volcano that brought them to the surface.

Lastly, as you probably know, water is found in lakes and rivers on the surface and "mined" from subterranean deposits below the surface. Aquifiers and the water table could be key words here. The oceans contain a vast supply of water, but due to its high mineral and organic content some processing is done before obtaining that of a useable quality.

Etcetera