RuneScape Classic Wiki
RuneScape Classic Wiki
The main RuneScape Wiki has an article on: Panning tray
The Old School RuneScape Wiki also has an article on Panning tray.

A panning tray is a quest item needed in the Digsite quest. It respawns in the large tent in the southern Digsite. After the player gives a cup of tea to the Digsite guide you'll able to continue progress with the quest and pan for items. Every time the pan is used 5 Mining experience is granted.

Found after searching

See also