Indeed, it was the second one discovered this month.

Via the BBC:  Second Mexico-US drug tunnel found in Tijuana

Police have uncovered a 670m (2,200ft) drug smugglers’ tunnel under the US-Mexico border – the second such discovery this month.

The tunnel links the Mexican city of Tijuana with Otay Mesa in California.

Earlier this month a tunnel equipped with ventilation and lights was found. Local media say the new tunnel may be even be more sophisticated.

Such tunnels are nothing new.  For examples see also: Border Tunnels Remain Unfilled  If We Only Had a Fence….  Oh, and it’s not just the southern border.  See:  Oh, That Border.