digger

function empty()
  turtle.dig()
  turtle.select(16)
  turtle.place()
  for i = 1,15 do
    turtle.select(i)
    turtle.drop()
  end
  turtle.select(16)
  turtle.dig()
  turtle.select(1)
end


function mine()
  turtle.dig()
  turtle.digUp()
  turtle.digDown()
  turtle.turnLeft()
  turtle.dig()
  turtle.turnRight()
  turtle.turnRight()
  turtle.dig()
  turtle.turnLeft()
end


function needFuel()
  turtle.dig()
  for i = 1,15 do
    turtle.select(i)
    turtle.refuel()
  end
  fuel = turtle.getFuelLevel()
  if fuel == 0 then
    empty()
    while turtle.getFuelLevel() == 0 do
      turtle.select(16)
      turtle.place()
      turtle.suck()
      turtle.refuel()
      turtle.drop()
      os.sleep(0.1)
    end
  turtle.select(16)
  turtle.dig()
  turtle.select(1)
  end
end

while true do
  if turtle.getItemCount(15) > 0 then
    empty()
  end
  turtle.select(1)
  mine()
  if turtle.getFuelLevel() == 0 then
    needFuel()
  end
  turtle.forward()
end