Well, this is hard to explain in a simple way. Different metals get concentrated by geological processes in different ways, and the geology of an area is pretty much the "why" for what particular minerals will be concentrated enough to make an ore deposit worthy of mining for a given metal.
Because of that, there is a bit of "metals are where you find them" problem, and some metals are found in very high concentrations in certain areas of the world and are essentially non-existent in ore form elsewhere. As with oil (same general idea that geology is why it is found where it is found), some countries have a lot of metal resources, and some do not. Certain large countries such as the US, Canada, and Russia have a lot of mineral resources simply because they have so much land area, so ores are found within the country even if those ores are generally only concentrated in certain parts of the country.
But the simple answer to your question is that all metals are mined: it is all dug from the ground somewhere. We dig them from the ground when the ground has a high enough concentration and a large enough total mass to make the mining effort pay (we can make money doing the job). I mean, you and I most certainly have gold (or almost any metal, truly) in our yard, for example, but the concentrations are so small that there is no point in digging it. It would cost way more to get it and purify for use than the value you could recover. Not worth the effort.