View difference between Paste ID: mFCd7JYg and j7T8hvrt

 local tArgs = { ... }
 if #tArgs ~= 1 then
 	print( "Usage: tunnel <length>" )
 	return
 end
 
 -- Mine in a quarry pattern until we hit something we can't dig
 local length = tonumber( tArgs[1] )
 if length < 1 then
 	print( "Tunnel length must be positive" )
 	return
 end
 
 local depth = length
 local collected = 0
 
 local function collect()
 	collected = collected + 1
 	if math.fmod(collected, 25) == 0 then
 		print( "Mined "..collected.." items." )
 	end
 end
 
 local function tryDig()
 	while turtle.detect() do
 		if turtle.dig() then
 			collect()
 			sleep(0.5)
 		else
 			return false
 		end
 	end
 	return true
 end
 
 local function tryDigUp()
 	while turtle.detectUp() do
 		if turtle.digUp() then
 			collect()
 			sleep(0.5)
 		else
 			return false
 		end
 	end
 	return true
 end
 
 local function refuel()
 	local fuelLevel = turtle.getFuelLevel()
 	if fuelLevel == "unlimited" or fuelLevel > 0 then
 		return
 	end
 
 	local function tryRefuel()
 		for n=1,16 do
 			if turtle.getItemCount(n) > 0 then
 				turtle.select(n)
 				if turtle.refuel(1) then
 					turtle.select(1)
 					return true
 				end
 			end
 		end
 		turtle.select(1)
 		return false
 	end
 
 	if not tryRefuel() then
 		print( "Add more fuel to continue." )
 		while not tryRefuel() do
 			sleep(1)
 		end
 		print( "Resuming Tunnel." )
 	end
 end
 
 local function tryUp()
 	refuel()
 	while not turtle.up() do
 		if turtle.detectUp() then
 			if not tryDigUp() then
 				return false
 			end
 		elseif turtle.attackUp() then
 			collect()
 		else
 			sleep( 0.5 )
 		end
 	end
 	return true
 end
 
 local function tryBack()
         refuel()
         while not turtle.back() do
                 if turtle.detect() then
-			if not tryDigDown() then
+                        if not tryDig() then
                                 return false
                         end
                 elseif turtle.attack() then
                         collect()
                 else
                         sleep( 0.5 )
                 end
         end
         return true
 end
 
 local function tryDown()
 	refuel()
 	while not turtle.down() do
 		if turtle.detectDown() then
 			if not turtle.digDown() then
 				return false
 			end
 		elseif turtle.attackDown() then
 			collect()
 		else
 			sleep( 0.5 )
 		end
 	end
 	return true
 end
 
 local function tryForward()
 	refuel()
 	while not turtle.forward() do
-	turtle.placeDown()
+
-	tryDigUp()
+
-	turtle.turnLeft()
+
-	tryDig()
+
-	tryUp()
+
-        tryDig()
+
-        tryUp()
+
-	tryDig()
+
-	turtle.turnRight()
+
-	turtle.turnRight()
+
-	tryDig()
+
-	tryDown()
+
-	tryDig()
+
-        tryDown()
+
-        tryDig()
+
-	turtle.turnLeft()
+
         tryDigUp()
         turtle.turnLeft()
         for x1=1,7 do
 		tryDig()
         	tryUp()
 	end
         turtle.turnRight()
         turtle.turnRight()
         tryForward()
 	for x2=1,7 do
        		tryDig()
         	tryDown()
         end
         tryBack()
         turtle.turnLeft()
 
 	if n<length then
 		tryDig()
 		if not tryForward() then
 			print( "Aborting Tunnel." )
 			break
 		end
 	else
 		print( "Tunnel complete." )
 	end
 
 end
 
 
 print( "Returning to start..." )
 
 -- Return to where we started
 turtle.turnLeft()
 turtle.turnLeft()
 tryUp()
 j = 0
 while depth > 1 do
 	if tryForward() then
 		depth = depth - 1
   j = j+1
    if j == 5 then
     turtle.select(15)
     turtle.placeDown()
    end
 	else
 		turtle.dig()
 	end
 end
 tryDown()
 turtle.turnRight()
 turtle.turnRight()
 
 
 print( "Tunnel complete." )
 print( "Mined "..collected.." items total." )