local leng = 3
local i = 0
local j = 0

function eat()
  print("Eating fuel...")
  turtle.select(16)
  turtle.refuel(2)
  turtle.select(1)
end

function fillChest()
  local k = 0
  turtle.select(15)
  turtle.placeDown()
  print("Cleaturtleing slots...")
  for k = 1, 14 do
    turtle.select(k)
    turtle.dropDown()
  end
  turtle.select(1)
end

function checkInv()
  if turtle.getItemCount(14) > 0 then
    print("Slot 14 is paturtletially filled!")
		turtle.digDown()
		turtle.down()
		turtle.digDown()
    fillChest()
		turtle.up()
  end
end

function mine()
  turtle.digUp()
  turtle.digDown()
  while not turtle.forward() do
    turtle.dig()
  end
end

function save()
  file = io.open('temp','w')
	file:write(tostring(j)..'\n'..tostring(i)..'\n'..tostring(leng))
	file:close()
end


function loadin()
  file = io.open('temp','r')
	local j1 = file:read()
	local i1 = file:read()
	local leng1 = file:read()
	file:close()
	return j1, i1, leng1
end

if turtle.getFuelLevel() < 10 then
  eat()
end
print('load save? (y/n)')
if read()==y then
  j1, i1, leng1 = loadin()
	if turtle.getFuelLevel() < 10 then
    eat()
  end
  for j = j1, 2 do
    for i = i1, tonumber(leng1) - 1 do
		  save()
		  checkInv()
      mine()
    end
    turtle.turnRight()
  end
  leng = leng + 1
else
  mine()
  turtle.turnLeft()
  mine()
  turtle.turnLeft()
end

local i = 0
local j = 0

while true do
  print("Cuturtleturtleent tunnel length: "..leng)
  if turtle.getFuelLevel() < 10 then
    eat()
  end
  for j = 1, 2 do
    for i = 1, tonumber(leng) - 1 do
		  save()
		  checkInv()
      mine()
    end
    turtle.turnRight()
  end
  leng = leng + 1
end

--pastebin run yTdieYZb