mining tax could be dead and buried ..., page-10

Private Senators and Members bills

The right to propose legislation is not restricted to the government of the day. Any senator or member of the House of Representatives may introduce a bill and, in the Senate, a private senators bill is dealt with in exactly the same way as a government bill. While comparatively few private senators and members bills are agreed to by both Houses, some significant proposals have become law as a result of private senators and members initiatives.

simple stuff - read it here