I HAVE to remember to bring food with me when I'm mining underground. I was playing around in Stephen's mine, got as deep as I could and then started line mining. Eventually ran into another giant cave with tons of iron, coal, gold, redstone and lapis. Got about two stacks of coal and redstone, a stack of iron and lapis, and probably 30 gold. Ran into a skeleton and then a zombie and then another skeleton and died. I had no idea how to get back to the mine, let alone where I died, so I lost everything, including a bunch of tools. /sigh