Lets solve some problems! Theres a few.

local vars = {}
local Pos = vector.new(0,0,0) --Base Position
local Side = "bottom"
local TargetPos = vector.new(0,0,0) -- Keep Y = 0
local MaxWest = -90
local MaxNorth = -55
local MaxEast = 10
local MaxSouth = 10
local ND = 0
local SD = 0
local Depth = 60
local Direction = "West"
local Drilling = true

if fs.exists("vars") then
local handle_0 = assert(fs.open("vars", "r"), "This maybe a little fucked.")
local input = handle_0.readAll()
handle_0.close()

vars = textutils.unserialize(input)
Pos = vars.pos
TargetPos = vars.targetpos
MaxWest = vars.maxwest
MaxNorth = vars.maxnorth
MaxEast = vars.maxeast
MaxSouth = vars.maxsouth
Direction = vars.direction
Drilling = vars.drilling
end
local function North(int)
print("North: "..int)
for I=1,int do
  Pos = Pos:sub(vector.new(0,0,1))
  redstone.setBundledOutput(Side,0)
  sleep(1.5)
  redstone.setBundledOutput(Side,8)
  sleep(1.5)
  Save()
end
end
local function East(int)
print("East: "..int)
for I=1,int do
  Pos = Pos:add(vector.new(1,0,0))
  redstone.setBundledOutput(Side,0)
  sleep(1.5)
  redstone.setBundledOutput(Side,1)
  sleep(1.5)
  Save()
end
end
local function South(int)
print("South: "..int)
for I=1,int do
  Pos = Pos:sub(vector.new(0,0,1))
  redstone.setBundledOutput(Side,0)
  sleep(1.5)
  redstone.setBundledOutput(Side,4)
  sleep(1.5)
  Save()
end
end
local function West(int)
print("West: "..int)
for I=1,int do
  Pos = Pos:sub(vector.new(1,0,0))
  redstone.setBundledOutput(Side,0)
  sleep(1.5)
  redstone.setBundledOutput(Side,2)
  sleep(1.5)
  Save()
end
end
local function Up(int)
print("Up: "..int)
for I=1,int do
  Pos = Pos:add(vector.new(0,1,0))
  redstone.setBundledOutput(Side,0)
  sleep(1.5)
  redstone.setBundledOutput(Side,16)
  sleep(1.5)
  Save()
end
end
local function Down(int)
print("Down: "..int)
for I=1,int do
  Pos = Pos:sub(vector.new(0,1,0))
  redstone.setBundledOutput(Side,0)
  sleep(1.5)
  redstone.setBundledOutput(Side,32)
  sleep(1.5)
  Save()
  if Pos.y == -6 then --ADJUSTABLE
   redstone.setOutput("top",true)
  end
end
redstone.setOutput("top",false)
end
local function Save()
vars.pos = Pos
vars.targetpos = TargetPos
vars.maxwest = MaxWest
vars.maxnorth = MaxNorth
vars.maxeast = MaxEast
vars.maxsouth = MaxSouth
vars.direction = Direction
vars.drilling = Drilling

local output = textutils.serialize(vars)
local handle_1 = assert(fs.open("vars", "w"), "Shits fucked.")
handle_1.write(output)
handle_1.close()
end
local function Check()
if redstone.getInput("front") then
  return true
else
  return false
end
end
local function MoveToPos(vec)
local x = vec.x
local y = vec.y
local z = vec.z

if y > Pos.y then
  Up(y - Pos.y)
elseif y < Pos.y then
  Down(Pos.y - y)
end

if x > Pos.x then
  East(x - Pos.x)
elseif x < Pos.x then
  West(Pos.x - x)
end

if z > Pos.z then
  South(z - Pos.z)
elseif z < Pos.z then
  North(Pos.z - z)
end
end
local function Mine()
Drilling = true
Save()
Down(Depth)
Drilling = false
Save()
sleep(1.5)
end
if Drilling then
Down(Depth+Pos.y)
Drilling = false
Save()
end
if ((Pos.x ~= TargetPos.x) or (Pos.z ~= TargetPos.z)) and not Drilling then
MoveToPos(TargetPos)
sleep(1.5)
Mine()
end
while true do
if Check() then
  if Check() and (Direction == "West") then
   while Pos.x > MaxWest do
	TargetPos.x = TargetPos.x - 10
	Save()
	MoveToPos(TargetPos)
	sleep(1.5)
	Mine()
   end
   MaxWest = MaxWest - 10
   Direction = "North"
   Save()
  end

  if Check() and (Direction == "North") then
   while Pos.z > MaxNorth do
	ND = Pos.z - MaxNorth
	if ND > 10 then
	 ND = 10
	end
	TargetPos.z = TargetPos.z - ND
	Save()
	MoveToPos(TargetPos)
	sleep(1.5)
	Mine()
   end
   MaxNorth = MaxNorth - 10
   Direction = "East"
   Save()
  end

  if Check() and (Direction == "East") then
   while Pos.x < MaxEast do
	TargetPos.x = TargetPos.x + 10
	Save()
	MoveToPos(TargetPos)
	sleep(1.5)
	Mine()
   end
   MaxEast = MaxEast + 10
   Direction = "South"
   Save()
  end

  if Check() and (Direction == "South") then
   while Pos.z < MaxSouth do
	SD = MaxSouth - Pos.z
	if SD > 10 then
	 SD = 10
	end
	TargetPos.z = TargetPos.z + SD
	Save()
	MoveToPos(TargetPos)
	sleep(1.5)
	Mine()
   end
   MaxSouth = MaxSouth + 10
   Direction = "West"
   Save()
  end
else
  sleep(10)
end
end