The underground city construction site was as busy as ever.
Tang Li had Tang Guo select 3,000 people from the Chinese nationals rescued from City D. They were divided into three shifts, working day and night to excavate earth and stone and install fluid confinement magnetic field equipment.
The excavated earth and stone were dumped in designated areas, separated from the surface soil below.
This separation was necessary because if soil and water were left together, Tang Li could absorb them all into her spatial dimension at once.
This would only fail if her spatial dimension was insufficient, in which case nothing would happen, and she couldn't absorb them.
Therefore, the excavated earth and stone had to be kept separate from the surface soil.
Upon arriving at the underground city construction site, Tang Li had also turned off the surveillance beforehand and had the operators controlling the wireless remote robots and brain-controlled slag trucks go offline.
Tang Li approached the pile of earth that had formed a small mountain and instantly absorbed it all into her spatial dimension.
Wasting no spatial capacity, Tang Li directly removed this earth and stone within her dimension.
Although the energy density of the earth and stone was extremely low, the sheer volume of it was enormous.
Furthermore, this earth and stone was mixed with the corpses or decaying matter of many insects, rats, plant roots, and other flora and fauna. These materials had a relatively high energy density.
Consequently, this pile of excavated underground earth and stone provided Tang Li with a significant amount of spatial energy.
Next, Tang Li went to the construction site's refueling station.
This refueling station was not like a pre-apocalypse gas station with pumps calculating liters and prices. Instead, fuel was directly drawn from oil drums using electric pumps and added to vehicles.
Refueling was done as needed, filling up the tanks.
While Tang Li was away, fuel was also transported remotely by vehicles.
Now, that was no longer necessary.
Tang Li absorbed the empty oil drums from the refueling station into her spatial dimension and then replicated many full ones to replenish the diesel fuel there.
After that, Tang Li took an elevator down into the underground levels.
Since Tang Li's underground city was built using robots and had no living people underground, the necessary environmental conditions for human survival were not provided.
Therefore, before going down, Tang Li took oxygen tanks from her spatial dimension and attached them to her mechanical exoskeleton to ensure her survival underground.
Similarly, the people controlling the wireless remote robots, brain-controlled slag trucks, and engineering mechs underground had also gone offline beforehand.
When Tang Li arrived underground, only the lights were on in the entire underground construction site, along with the sounds of some engineering machinery. All construction had been paused.
Tang Li had avatars underground, and she was very familiar with the underground construction site.
Before arriving, Tang Li had instructed the construction workers to park all faulty machinery in designated locations.
Naturally, there were people responsible for repairing machinery at the construction site.
However, repairing machinery could sometimes be too time-consuming, and Tang Li had prepared many backup machines.
As for the broken machinery, whether it was wireless brain-controlled robots, slag trucks, or engineering mechs, minor issues were repaired. If there were major issues, or if repairs would affect construction progress, they were simply set aside.
Tang Li's purpose for coming underground this time was to retrieve these malfunctioning machines into her spatial dimension and then replicate new ones.
She primarily retrieved those with major problems, and even those with minor issues that were idle would be replaced with new ones.
For Tang Li, even if these machines broke down, absorbing them into her spatial dimension and replicating them resulted in no loss.
With these tasks completed, Tang Li's objectives at the underground city construction site were all fulfilled.
Although she gained some spatial energy when absorbing the earth and stone, she consumed a lot of it when replicating diesel fuel.
Even though this earth and stone was transported from underground by slag trucks that consumed diesel.
However, the energy density of diesel fuel was far greater than that of earth and stone.
In this exchange, Tang Li actually lost some spatial energy.
But as long as the underground city could be built, this expenditure was worthwhile.
Subsequently, until February 24, 343, for four months, Tang Li visited the underground city construction site every few days to perform these tasks.
The specific interval depended on the underground city's diesel consumption and machinery wear and tear.
As long as it didn't delay the construction progress of the underground city.
As for the excavated earth and stone?
The amount excavated in the previous ten-plus days was sufficient for storage, and leaving it for only a few days now was also not a problem.
By February 24, 343, the main structure of the underground city had been completely excavated and was awaiting the arrival of the official underground city modules for installation.
The authorities had not anticipated Tang Li building the underground city so quickly, but they had already prepared underground city modules of various models.
On February 25, Tang Li disguised herself as Boss Li and, braving the north wind, personally drove to Jiangcheng.
She intended to replicate the underground city modules before the meteorite impact and install them underground!