Turtle world eater NO ENDERCHEST

-- pastebin get FFpY2V5c worldeater

i = 0
block = "false"
data = "false"
height = 0
---------------------
function bottom() --bottom out to find y level
  height = 0
  while true do
    block,data = turtle.digDown()
      if data == "Unbreakable block detected" then
        break
      end
    while turtle.dig() do
    end
    height = height + 1
    turtle.down()
  end
end
-----------------------
function empty() -- place soryn chest and empty. this function is run after clear()
  while turtle.dig() do
    sleep(.2)
  end
  while turtle.digUp() do
    sleep(.2)
  end
  turtle.turnRight()
  turtle.turnRight()
  while turtle.dig() do
    sleep(.3)
  end
  turtle.select(16)
  turtle.place()
  for i = 1, 14 do
    turtle.select(i)
    turtle.drop()
  end
  turtle.turnRight()
  turtle.turnRight()
  turtle.select(1)
  while turtle.dig() do
    sleep(.2)
  end
  turtle.forward()
  while turtle.dig() do
    sleep(.2)
  end
  turtle.forward()
end

-----------------------
function turtleRefuel()
  if turtle.getFuelLevel() < 5000 then
  for i=1,14 do
    turtle.select(i)
    turtle.refuel()
    turtle.select(1)
  end
  end
end
-----------------------
function lowFuel() -- checks for low fuel and waits if at top of loop
  if turtle.getFuelLevel() < 200 then
  turtle.select(15)
  turtle.refuel(turtle.getItemCount(15)-1)
  turtle.select(1)
  print("WARNING: Low Fuel")
  if yLevel > height then
    print("Waiting for fuel")
    os.pullEvent("turtle_inventory")
  end
  end
end
---------------------
function self()
  turtleRefuel()
  lowFuel()
  lowFuel()
  turtle.getFuelLevel()
end
--------------------
function minerUp() -- bottom to top mining
  for i=1,height do
  while turtle.digUp() do
    sleep(.2)
  end
  while turtle.dig() do
    sleep(.2)
  end
  turtle.up()
  end
end
-------------------
function inventory() -- check for fuel and enderchest
  print("fuel in slot 15")
  print("64x chests in slot 16")
  turtle.dig() --just in case it is placed before a restart
  while turtle.getItemCount(16) == 0 do
    os.pullEvent("turtle_inventory")
  end
end
--------------------
-- Main function
-- start with going to bedrock

inventory()
-- the turtle miner is now ready

while turtle.getItemCount(16) > 1 do
bottom()
self()-- fuel check
empty()-- place chest, empty, "leave" chest, move into postion
  print("Mining Up")
minerUp()
self()-- fuel check
empty()-- place chest, empty, "leave" chest, move into postion
  print("Mining Down")
end