Minecraft Crashes when i come near to my mining cave.

Hi Mojang and Mega Spud!!! Today i was playing Minecraft in survival in my survival world. When i was playing survival i think i should go to my minning cave where i mine ores, get loots from mineshafts so i called that cave a minning cave so when i decided to come to my minning cave i sprint and started to walk fastly when i come near to my minning cave i crash i just say this happens in beta sometimes and beta is unstable version so i played my world this time i was near to my house and it was raining i say strange raining before crashing it was not raining okay whatever so i started to walk faslty and come to near my minning cave and i crash again and this was happening again and again when i come near to my minning cave. so here is my crash report and please fix this crash and thankyou!!!