After 25 years of planning and construction, that blast will clear the way for a scheduled 2017 completion of the 57-km-long high-speed and freight rail connection through the Alps.
More than 2,500 workers have toiled to bring this engineering feat to reality, using state-of-the-art technology to carve their way through the hardest minerals known to man.
Where Hannibal had to rely upon elephants to arduously move his armies across the Alps, soon high-speed passenger expresses and heavy-duty freight trains will bypass winding mountain routes by zipping underneath them.
This is not the first triumph of Swiss tunnel technology at St. Gotthard. Back in 1882, the Swiss carved out their first St. Gotthard rail tunnel, and there has been a 17-km-long road tunnel since 1980 - each heralded as a technological marvel.
Not to mention, the St. Gotthard Pass Road of 1830. But when you enter the the yawning maul of the Gotthard Base Tunnel, your heart might just skip a beat - so overwhelming are its dimensions.
Trains will be able to traverse the world's longest rail tunnel at speeds of 270 km an hour.
Indeed, speed and sophisticated engineering are the hallmarks of this project - comparable to the building of the Suez Canal, in its day a similar marvel of transport engineering. The tunnel system, with all its side tunnels and components, encompasses 152 km.
Work is progressing so swiftly that rail service could be inaugurated in 2016, a full year ahead of schedule.
On the downside, seven lives have been lost since the first shovel touched soil. In another nod to the modern age, air-conditioning technology enables the workers to toil in balmy 28 degrees Celsius, as opposed to 40 degrees outside the cooled bubble.
The crews staff 400-metre-long tunnel boring machines with 60 bits on their 10-metre-diameter bore heads, chewing their way through stone with 25-tonne pressure.
Steel nets cover the walls and conveyor belts carry the stone out of the site. In all, 13 million cubic metres of material will be extracted from the mountain - five times the volume of the Great Pyramid and enough to fill a freight train from Zurich to New York.
The final blast is being carried out with surgical precision, with a vertical and horizontal leeway of just one centimetre.
Where the tunnel is already accessible on foot, the view is breathtaking. It is like being in a subterranean palace - albeit one devoid of any adornment whatsoever.
Well beyond the portals, eerie lighting illuminates a scene of monstrous machines and workers in helmets. There is a palpable sense that hundreds of thousands of tonnes of stone are right above your head.
Once the 230 km of rail are laid, 300 passenger and freight trains will roar through the tunnel daily, roughly double the current volume. The trip from Zurich to Milan will take 2 hours and 40 minutes - an hour less than it does now.
Freight trains will also be able to hasten their journey. At up to 160 kmh, freight will double its current transport speed.
The Swiss consistently have elected to send freight by rail through the Alps rather than by road, much like their European neighbours.
While not part of the European Union, Switzerland's tunnels meet the bloc's standards for freight transport.
That has cost the Swiss more than 15 billion euros - money well invested, as the EU Commission anticipates a 75 percent increase in freight traffic in the entire Alpine region.
The New Railway Link Through the Alps (NRLA), also known by its German acronym NEAT, consists of numerous tunnels.
Besides the St. Gotthard Base Tunnel, the Ceneri Base Tunnel is being built in Canton Ticino, in Switzerland's south, with an eye towards a 2019 completion date. And the Loetschberg Base Tunnel is already running at nearly 80 percent capacity.
And now the light at the end of the St. Gotthard Base Tunnel. The first breakthrough is to be carried out in the east bore of the two-bore tunnel - 40 metres apart from each other - joined every 312.5 metres by connecting tunnels.
The final cut is 27 km from the northern portal at the village of Erstfeld in the central Canton Uri, and 30 km from the southern portal at Bodio in Canton Ticino.
It lies 2,500 metres under the summit of Piz Vatgira, a 2,983-metre-hight peak. Already, a small hole has been created through which draft of fresh air rolls into the tunnel.
The opening is a scant 6 centimetre window created in order to lay the cable for live television coverage of the Oct 15 ceremonies.