Mining Fiesta is an Event that occurs when Cole (or in some cases, Foxy or Mayor Jerry) is elected as Mayor. This event occurs during the beginning of Early Summer and Early Autumn on the Calendar, equal to a total of 5 hours and 20 minutes in real time. The event grants players 1.5x Mining XP, double the mining drops, and allows players to collect Refined Minerals from ores. Refined Minerals are fairly common and sell for roughly 20,119 coins on the bazaar, making them decently profitable for early-game players. They are also a good way to level up their Mining skill, which is an important early-game staple, as it allows players to use higher tier Reforge Stones.
There's a chance that Foxy's third perk Extra Event will select this as the yearly additional event.
The first event happened in Year 90 due to the above reason.
During the first few hours of the event, the drop rate of refined minerals was broken and was extremely high, this glitch was fixed later on in the event.
The event time of the Mining Fiesta was changed from the first event. Originally, the previously named National Mining Month occur during the end of Late Summer and the beginning of Early Autumn. Now, it happens at Early Summer and Early Autumn lasting 5 hours and 20 minutes each session.