In PE if on your world (server) you have a beach x2, a mountain and lots of rivers, then this is the cheat for you. Firstly, follow one of your rivers (i always take a bed just in case) and when you find a beach that goes inland, follow the beach. If the beach does not lead into a mountain (and i mean INTO the mountain) then go back to the river and find another beach, but if the beach does go into the mountain, mine into the mountain, this took me about 4-5 minecraft days (thats why take bed) and also take about 20 wooden pickaxes or 10 stone or 13 gold or 3 iron or 2 diamond. In the centre of the mountain you will find a long shaft. On the walls of the shaft there will be loads of minecart rails. If not find a bigger mountain. If this cheat does not work, i am sorry but do not know at this very second the solution, i will soon find out.