I highly recommend you look through the text leisurely in preparation for needing other metals that aren't obvious, or not only in one type of vein...
I'll give an example, Sb stibnite, also known as antimony is "hidden" in Tetrahedrite(one type of copper) veins... Any ores you click in the book will take you to the correct page for a vein that contains it... it might just be that the vein has another metal/gem ore as it's main ore.
A vein as noted in Jason's post can contain four different ores.
And just as a side note, Cassiterite Ore, when processed correctly gives more than two times the tin as Tin Ore does, so I urge you to keep it unrefined for after you have at the least a macerator to process it initially