When did Miri Airport open?

I’m really curious about this. When did Lutong Airport (WMLU) close down and when did Miri Airport (MYY/WBGR) (the very old one, no aircond one) started operation?

http://en.wikipedia.org/wiki/Miri_Airport
http://en.wikipedia.org/wiki/Lutong_Airport

Actual date, don’t know but all the basic info’s you can find it above links.