Mining Turtle Strip Mine Program

-- Strip mining turtle program.
-- Luke *********, Ryszard ********. 13/12/12
-- updated by AzrylAero 5/3/2013

--[[fuel must be placed in slot 14,
    mainshaft torches must be placed in slot 15
    tunnel torches must be placed in slot 16.]]

-- Create the function for refueling
function checkFuel()
  if turtle.getFuelLevel() <= 10 then
    turtle.select(14)
    turtle.refuel(1)
    turtle.select(1)
  end --if
end --checkFuel()

-- Create the turnAround function
function turnAround()
  turtle.turnRight()
  turtle.turnRight()
end --turnAround()

-- Go to the next tunnel
function digNext(torchCounter)
   turtle.turnRight()
  turtle.dig()
  turtle.forward()
  turtle.digUp()
  turtle.dig()
  turtle.forward()
  turtle.digUp()
  if torchCounter == 2 then

   turnAround()
   turtle.select(15)
   turtle.place()
   turnAround()
   print("Placing mainshaft torch")
  end
  turtle.turnLeft()
  print("turn Right")
  print("Next Tunnel")
end


--Dig Next End

-- Digs the tunnel for the given length
function tunnel(givenLength)
  local distance = 0
  for index = 1,givenLength do
    turtle.dig()
    if turtle.forward() then
      distance = distance + 1
    end --if
    turtle.digUp()
    turtle.select(1)
    turtle.placeDown()

-- Places a torch every 10 blocks
    if distance == 10 then
      turtle.select(16)
      print("Placing tunnel torch...")
      turnAround()
      turtle.place()
      turnAround()
      distance = 0
      checkFuel()
    end --if
  end --for

-- Sends the turtle back to the start
   turtle.up()
   for index = 1,givenLength do
   turtle.back()
   end --for
   turtle.down()
end --tunnel()

-- Main script
print("Input tunnel length:")
local length = read()
print("Tunnel quantity")
local quantity = read()
local torchNext = 0
print("starting excavation...")
checkFuel()
-- Tunnel loop
  for index=1,quantity do
  if torchNext == 3 then
    torchNext = 0
  end
  tunnel(length)
  checkFuel()
  digNext(torchNext)
  torchNext = torchNext + 1
 end
print("The tunnel(s) has been excavated!")