mine

emptyInv = function()
  while(1) do
    if not turtle.detectUp() then
      turtle.up()
    else
      local steps = 0
      turtle.turnRight()
      turtle.turnRight()
      while(1) do
        if not turtle.detect() then
          turtle.forward()
          steps = steps + 1
        else
          for i = 1,16,1 do
            turtle.select(i)
            turtle.dropUp()
          end
          break
        end
      end
      turtle.turnRight()
      turtle.turnRight()
      for j = 1,(steps+1),1 do
        turtle.forward()
      end
      break
    end
  end
end
local arg = {...}
emptyInv()
for i = 1,arg[1],1 do
  while(1) do
    turtle.select(1)
    if turtle.detectDown() and turtle.digDown() then
    elseif not turtle.detectDown() then
    else
      emptyInv()
      break
    end

    if turtle.getItemCount(16) > 0 then
      emptyInv()
    end

    turtle.down()
  end
  while turtle.detect() do
    turtle.dig()
  end
end