The panning tray is a quest item used in the digsite to pan for gold.
Can also be used before the quest if you bribe the Panning guide with a cup of tea.
It is needed in the Digsite Quest to retrieve a special cup, and there is a chance of finding an opal, which is also needed in the quest.
When panning, players can find gold nuggets, an oyster, an uncut opal, an uncut jade, and coins.