torch

turtle.select(1)
turtle.refuel()
for i=0,5 do
  turtle.up()
end
while turtle.getItemCount(2) > 0 do
  if turtle.getFuelLevel() == 0 then
    turtle.select(1)
    turtle.refuel()
  end
  for i=0,5 do
    if turtle.detect() then
      turtle.dig()
    end
    turtle.forward()
  end
  count = 0
  while count < 6 do
    if turtle.detectDown() then
      turtle.digDown()
    end
    turtle.down()
    count = count + 1
  end
  turtle.dig()
  turtle.select(2)
  turtle.place(2)
  for i=1,count do
    turtle.up()
  end
end