Tekkit Turtle NetherTunnel

print("Length")
local length = io.read()
length = tonumber(length)

function makeBridge()
 refuel()
 if turtle.detect() then
  turtle.dig()
 end
 getResource(2,16)
 turtle.placeDown()
 turtle.turnLeft()
 getResource(2,16)
 turtle.place()
 turtle.turnLeft()
 turtle.turnLeft()
 getResource(2,16)
 turtle.place()
 turtle.turnLeft()
 turtle.digUp()
 turtle.up()
 if turtle.detect() then
  turtle.dig()
 end
 getResource(2,16)
 turtle.placeUp()
 turtle.turnLeft()
 getResource(2,16)
 turtle.place()
 turtle.turnLeft()
 turtle.turnLeft()
 getResource(2,16)
 turtle.place()
 turtle.turnLeft()
 turtle.down()
 turtle.forward()
end
function refuel()
 if turtle.getFuelLevel() == 0 then
  print("Fuel Zero")
  if turtle.getItemCount(1) == 0 then
   print("Waiting for Fuel")
   while turtle.getItemCount(1) == 0 do
    sleep(1)
   end
  end
  turtle.select(1)
  turtle.refuel(1)
 end
end

function getResource(min,max)
 local n = min
  while turtle.getItemCount(n) == 0 do
   n = n + 1
   if n > max then
    sleep(1)
    n = min
   end
 end
 turtle.select(n)
end
local d = 0
while d < length do
 d = d + 1
 makeBridge()
end