When I copied a world from my iPhone 4 to my iPad 2 half of my mine and about 4 dozen trees I cut down came back, but when I looked in my inv, all the items from mining (iron gold lapis and diamonds) and around 4 stacks of wood logs were still in my inv. I redug my mine and found all the lapis gold iron and diamonds right where I found them but the ones in my inv from before I copied the world were still useable and everything.