The fire-heating and water-quenching method of splitting stone could not be called useless, but it depended on what you compared it to.
If it had been used to build Dujiangyan during the Pre-Qin Period, it would certainly have been advanced. At the very least, it would have been far more powerful than human labor.
But compared with the Han Tribe now, things were different.
Leaving aside the Han Tribe's explosives, even without explosives, directly using Rock Drills to chisel through the stone would probably be faster and cheaper than the fire-heating and water-quenching method.
The fire-heating and water-quenching method required a great deal of firewood, as well as a great deal of time. Without burning the stone for seven or eight hours, how could it possibly be heated until it was scorching hot? If the stone did not reach a high enough temperature, pouring water over it would merely cool it down and accomplish nothing.
So really, this method was not even as good as using explosives. Even Black Powder was far more effective.
Thus, You Fu discussed the matter with Yang Xin and immediately abandoned the fire-heating and water-quenching method.
There was no gunpowder at the construction site for the time being, so they simply used Rock Drills to slowly cut through the stone. Besides, this speed was not much slower than the fire-heating and water-quenching method.
As for gunpowder, You Fu had considered following the example of the Cross-Sea Bridge Construction Site and producing Black Powder themselves, but after thinking it over carefully, he abandoned the idea.
Their situation here was different from that at the Cross-Sea Bridge.
The project over there was a fixed project. The bridge was right there, and it would not move.
The quarrying mountain was also beside the camp and would not move