[LUA] Global vector keeps getting reset?

local mineLocation = vector.new(2,0,0)
local location = vector.new(0,0,0)

-- miners start pointing backwards towards their chest.
-- '0' indicates positive x, '1' positive y, '2' negative x, '3' negative y
-- a right turn adds 1 to direction, a left turn subtracts
-- every time direction is modified, it is also normalized to remain between 0 and 3 inclusive
local direction = 2

local toMine = function()
	print("Going to Mine")
	print("Retreiving Mine Location")
        -- THIS ALWAYS PRINTS (0,0,0) --
	print("(" .. mineLocation.x .. "," .. mineLocation.y .. "," .. mineLocation.z .. ")")
	print("")
	tmpVec = mineLocation - location
	
	-- if positive x
	if tmpVec.x > 0 then
		-- face positive x
		while direction ~= 0 do
			right()
		end
                -- move in that direction
		for i=1,tmpVec.x do
			forward()
		end
	end
	-- if negative x
	if tmpVec.x < 0 then
		-- face negative x
		while direction ~= 2 do
			right()
		end
                -- move in that direction
		for i=tmpVec.x,-1 do
			forward()
		end
	end
	
	-- if positive y
	if tmpVec.y > 0 then
		-- face positive y
		while direction ~= 1 do
			right()
		end
                -- move in that direction
		for i=1,tmpVec.y do
			forward()
		end
	end
	--if negative y
	if tmpVec.y < 0 then
		-- face negative y
		while direction ~= 3 do
			right()
		end
                -- move in that direction
		for i=tmpVec.y,-1 do
			forward()
		end
	end
	
	-- if positive z
	if tmpVec.z > 0 then
		for i=1,tmpVec.z do
			down()
		end
	end
        -- if negative z
	if tmpVec.z < 0 then
		for i=tmpVec.z,-1 do
			up()
		end
	end
end

while true do
	if refuel() then
		toMine(mineLocation) -- THIS WORKS FINE AND MOVES TURTLE TO <2,0,0>
		while (turtle.getFuelLevel() > 1600) do
			for j=1,tArgs[2] do -- ROWS
				for i=2,tArgs[1] do -- COLUMNS (-1 from column length as you need to move one less space than you need to dig)
					if turtle.detectDown() then
						turtle.digDown()
					end
					forward()
				end
				turtle.digDown()
				
				if turtle.getItemCount(15) ~= 0 then -- If all slots now have something in them we're pretty full. Might as well empty the inventory.
					mineLocation = location -- THIS IS WHERE I THINK EVERYTHING IS GOING WRONG --
					print("Recording Mine Location")
                                        -- THIS PRINTS THE RIGHT VALUES --
					print("(" .. mineLocation.x .. "," .. mineLocation.y .. "," .. mineLocation.z .. ")")
					print("")
					returnToStart() -- PRACTICALLY THE SAME ALGORITHM AS toMine() BUT DOESN'T TOUCH mineLocation AT ALL --
					refuel()
					toMine()
				end
			end
			returnToCorner()
			down()
		end
	else
		print("Ran out of fuel")
		sleep(120)
	end
end

local naturalizeDirection = function(z)
	dir = direction + z
	if dir > 3 then
		dir = dir % 4
	end
	if dir < 0 then
		dir = dir + 4
	end
	return dir
end

local turnTo = function(d)
    if direction == d then
        return true
    else
        change = d - direction
        if change == 2 or change == -2 then
            right()
            right()
        elseif change == 1 or change == -3 then
            right()
        elseif change == 3 or change == -1 then
            left()
        end
    end
end

local right = function()
	turtle.turnRight()
	direction = naturalizeDirection(1)
end

local left = function()
	turtle.turnLeft()
	direction = naturalizeDirection(-1)
end

local up = function()
	if not turtle.up() then
		return false
	end
	location.z = location.z - 1
	return true
end

local down = function()
	if not turtle.down() then
		return false
	end
	location.z = location.z + 1
	return true
end

local forward = function()
	if turtle.detect() then
		turtle.dig()
	end
	if not turtle.forward() then
		return false
	end
	if direction == 0 then
		location.x = location.x + 1
	elseif direction == 1 then
		location.y = location.y + 1
	elseif direction == 2 then
		location.x = location.x - 1
	elseif direction == 3 then
		location.y = location.y - 1
	end
	return true
end

local back = function()
	if not turtle.back() then
		return false
	end
	if direction == 0 then
		location.x = location.x - 1
	elseif direction == 1 then
		location.y = location.y - 1
	elseif direction == 2 then
		location.x = location.x + 1
	elseif direction == 3 then
		location.y = location.y + 1
	end
	return true
end