View difference between Paste ID: W86Lp9wu and xwwVsp5s

 -- For some reason the turtle had trouble DLing the last paste
 -- Turtle Excavator w/ EnderChest support
 -- Stop wasting precious fuel by returning to the surface to unload.
 -- Best used with a Chunk Loader Mining Turtle.
 -- Mods Required - EnderStorage, ComputerCraft
 -- Recommended Mods - MiscPeripherals (for the Chunk Loader Turtle ad-on)
 -- Brought to you by Lizarddemon94 and TheCountChuckula
 local tArgs = { ... }
 if #tArgs ~= 1 then
 	print( "Usage: excavate <diameter>" )
 	return
 end
 
 print( "Place your Auto-Sorting Ender Chest" )
 print( "into Slot 1. A small stack of coal" )
 print( "(5-10) into Slot 2." )
 print( "Press any key to continue..." )
 os.pullEvent("char")
 
 -- Mine in a quarry pattern until we hit something we can't dig
 local size = tonumber( tArgs[1] )
 if size < 1 then
 	print( "Excavate diameter must be positive" )
 	return
 end
 
 local depth = 0
 local unloaded = 0
 local collected = 0
 
 local ender = 1
 local fuel = 2
 
 local xPos,zPos = 0,0
 local xDir,zDir = 0,1
 
 local goTo -- Filled in further down
 local refuel -- Filled in further down
 
 local function unload( _bKeepOneFuelStack )
 	print( "Unloading items..." )
  turtle.select(ender)
  turtle.placeUp()
 	for n=3,16 do
 		local nCount = turtle.getItemCount(n)
 		if nCount > 0 then
 			turtle.select(n)
    turtle.dropUp()
   end
   unloaded = unloaded + nCount
  end
  turtle.select(ender)
  turtle.digUp()
 	collected = 0
 	turtle.select(2)
 end
 
 local function returnSupplies()
 	local x,y,z,xd,zd = xPos,depth,zPos,xDir,zDir
 	print( "Emptying slots..." )
 
 	local fuelNeeded = 2*(x+y+z) + 1
 	if not refuel( fuelNeeded ) then
 		unload( true )
 		print( "Waiting for fuel" )
 		while not refuel( fuelNeeded ) do
 			sleep(1)
 		end
 	else
 		unload( true )
 	end
 
 	print( "Resuming mining..." )
 	goTo( x,y,z,xd,zd )
 end
 
 local function collect()
 	local bFull = true
 	local nTotalItems = 0
 	for n=3,16 do
 		local nCount = turtle.getItemCount(n)
 		if nCount == 0 then
 			bFull = false
 		end
 		nTotalItems = nTotalItems + nCount
 	end
 
 	if nTotalItems > collected then
 		collected = nTotalItems
 		if math.fmod(collected + unloaded, 50) == 0 then
 			print( "Mined "..(collected + unloaded).." items." )
 		end
 	end
 
 	if bFull then
 		print( "No empty slots left." )
 		return false
 	end
 	return true
 end
 
 function refuel( ammount )
 	local fuelLevel = turtle.getFuelLevel()
 	if fuelLevel == "unlimited" then
 		return true
 	end
 
 	local needed = ammount or (xPos + zPos + depth + 1)
 	if turtle.getFuelLevel() < needed then
 		local fueled = false
 		for n=2,2 do
 			if turtle.getItemCount(n) > 0 then
 				turtle.select(n)
 				if turtle.refuel(1) then
 					while turtle.getItemCount(n) > 0 and turtle.getFuelLevel() < needed do
 						turtle.refuel(1)
 					end
 					if turtle.getFuelLevel() >= needed then
 						turtle.select(2)
 						return true
 					end
 				end
 			end
 		end
 		turtle.select(2)
 		return false
 	end
 
 	return true
 end
 
 local function tryForwards()
 	if not refuel() then
 		print( "Not enough Fuel" )
 		returnSupplies()
 	end
 
 	while not turtle.forward() do
 		if turtle.detect() then
 			if turtle.dig() then
 				if not collect() then
 					returnSupplies()
 				end
 			else
 				return false
 			end
 		elseif turtle.attack() then
 			if not collect() then
 				returnSupplies()
 			end
 		else
 			sleep( 0.5 )
 		end
 	end
 
 	xPos = xPos + xDir
 	zPos = zPos + zDir
 	return true
 end
 
 local function tryDown()
 	if not refuel() then
 		print( "Not enough Fuel" )
 		returnSupplies()
 	end
 
 	while not turtle.down() do
 		if turtle.detectDown() then
 			if turtle.digDown() then
 				if not collect() then
 					returnSupplies()
 				end
 			else
 				return false
 			end
 		elseif turtle.attackDown() then
 			if not collect() then
 				returnSupplies()
 			end
 		else
 			sleep( 0.5 )
 		end
 	end
 
 	depth = depth + 1
 	if math.fmod( depth, 10 ) == 0 then
 		print( "Descended "..depth.." metres." )
 	end
 
 	return true
 end
 
 local function turnLeft()
 	turtle.turnLeft()
 	xDir, zDir = -zDir, xDir
 end
 
 local function turnRight()
 	turtle.turnRight()
 	xDir, zDir = zDir, -xDir
 end
 
 function goTo( x, y, z, xd, zd )
 	while depth > y do
 		if turtle.up() then
 			depth = depth - 1
 		elseif turtle.digUp() or turtle.attackUp() then
 			collect()
 		else
 			sleep( 0.5 )
 		end
 	end
 
 	if xPos > x then
 		while xDir ~= -1 do
 			turnLeft()
 		end
 		while xPos > x do
 			if turtle.forward() then
 				xPos = xPos - 1
 			elseif turtle.dig() or turtle.attack() then
 				collect()
 			else
 				sleep( 0.5 )
 			end
 		end
 	elseif xPos < x then
 		while xDir ~= 1 do
 			turnLeft()
 		end
 		while xPos < x do
 			if turtle.forward() then
 				xPos = xPos + 1
 			elseif turtle.dig() or turtle.attack() then
 				collect()
 			else
 				sleep( 0.5 )
 			end
 		end
 	end
 
 	if zPos > z then
 		while zDir ~= -1 do
 			turnLeft()
 		end
 		while zPos > z do
 			if turtle.forward() then
 				zPos = zPos - 1
 			elseif turtle.dig() or turtle.attack() then
 				collect()
 			else
 				sleep( 0.5 )
 			end
 		end
 	elseif zPos < z then
 		while zDir ~= 1 do
 			turnLeft()
 		end
 		while zPos < z do
 			if turtle.forward() then
 				zPos = zPos + 1
 			elseif turtle.dig() or turtle.attack() then
 				collect()
 			else
 				sleep( 0.5 )
 			end
 		end
 	end
 
 	while depth < y do
 		if turtle.down() then
 			depth = depth + 1
 		elseif turtle.digDown() or turtle.attackDown() then
 			collect()
 		else
 			sleep( 0.5 )
 		end
 	end
 
 	while zDir ~= zd or xDir ~= xd do
 		turnLeft()
 	end
 end
 
 if not refuel() then
 	print( "Out of Fuel" )
 	return
 end
 
 print( "Excavating..." )
 
 local reseal = false
 turtle.select(1)
 if turtle.digDown() then
 	reseal = true
 end
 
 local alternate = 0
 local done = false
 while not done do
 	for n=1,size do
 		for m=1,size-1 do
 			if not tryForwards() then
 				done = true
 				break
 			end
 		end
 		if done then
 			break
 		end
 		if n<size then
 			if math.fmod(n + alternate,2) == 0 then
 				turnLeft()
 				if not tryForwards() then
 					done = true
 					break
 				end
 				turnLeft()
 			else
 				turnRight()
 				if not tryForwards() then
 					done = true
 					break
 				end
 				turnRight()
 			end
 		end
 	end
 	if done then
 		break
 	end
 
 	if size > 1 then
 		if math.fmod(size,2) == 0 then
 			turnRight()
 		else
 			if alternate == 0 then
 				turnLeft()
 			else
 				turnRight()
 			end
 			alternate = 1 - alternate
 		end
 	end
 
 	if not tryDown() then
 		done = true
 		break
 	end
 end
 
 print( "Returning to surface..." )
 
 -- Return to where we started
 returnSupplies()
 goTo( 0,0,0,0,-1 )
 unload( false )
 goTo( 0,0,0,0,1 )
 
 -- Seal the hole
 if reseal then
 	turtle.placeDown()
 end
 
 print( "Mined "..(collected + unloaded).." items total." )