In the past few days, every time Li Yu used the military radio to contact the Big Camphor Tree Base, he would intentionally or unintentionally ask about the fortifications there.

To the east of Gansheng is Min Province, and to the south is Guangdong Province. Both provinces are near the sea and are places where typhoons often make landfall.

However, Gansheng is surrounded by mountains on all sides, with Nanling to the south and the Wuyi Mountain Range to the east. The presence of these mountains should significantly weaken the typhoon's power.

But Li Yu still felt a bit uneasy and was quite concerned about this matter.

Here in Oil City, it is located in the Central Plains, far from the coast, so by the time the typhoon reaches here, much of its moisture should have dissipated.

Li Tie and the others are also making preparations, counting vehicles, and getting ready for the main force to return to the Big Camphor Tree Base.

This time, they cleared out the Motorcycle Gang's hideout, seized their food and ammunition, then found a lot of firearms and vehicles at the Zheng City military district, and combined with the oil produced in Oil City these days, all this needs to be taken back to the Big Camphor Tree Base.

If they relied solely on helicopter transport, with two trips a day, it would probably take one or two months to finish.

So they have to use vehicles to transport everything back.

Altogether, there are over a hundred vehicles of various sizes.

This includes military trucks, tanks, infantry fighting vehicles, armored personnel carriers...

There are also more trucks and cargo trucks scavenged from the Motorcycle Gang's hideout, all loaded with various supplies.

Originally, Li Yu considered transporting the oil directly by helicopter, but found that the oil was too heavy, and the helicopters had too little carrying capacity, only a dozen tons or so, and they were also big oil consumers. If not for the continuous oil production in Oil City, they wouldn't even be able to afford using the helicopters.

On average, one round trip, after deducting the fuel consumption of six or seven tons, would only allow them to bring back a few tons.

The efficiency is too low.

It's convenient to use helicopters for carrying people, but it's somewhat wasteful to use them for transport.

So the best method is still land transport.

........

Time flows like water, slowly passing by.

Four days later.

The trench outside the wall of Oil City has been fully constructed.

The trench turned out to be more complex than they anticipated due to having to account for the terrain's height difference, ensuring that the closer it got to Oil City, the higher it was.

This way, they could utilize the drop to let the oil flow out.

Additionally, the depth of the trench was ten centimeters higher than they originally planned, with the deepest part reaching thirty centimeters and the part closest to Oil City fifteen centimeters.

And the trench is covered with a thin layer of cement, separating it from the soil to prevent oil from seeping into the ground and being wasted.

In the evening.

After distributing the day's food with their collaborators, Old Bi and others announced that there were temporarily no engineering tasks left for them, thus concluding their collaboration with Oil City.

The people were somewhat prepared for this, given that such a large number of them consumed a significant amount of food daily.

However, when the day finally arrived, they still felt a bit disappointed, leading to a sense of confusion about what to do next.

More crucially, they didn't know where to find food after collecting today's share.

Seeing the disappointed expressions on their faces, Old Bi raised his voice and said:

"Although the engineering here is temporarily over, there may be more projects in the future, and I will reach out to everyone at that time.

Additionally, I still have a list of food exchange items here, and you can exchange things based on what's on it. For example, gold, one pound of gold can be exchanged for two pounds of food...."

Gold has always been a hard currency, both before and after the apocalypse.

Due to gold's unique and perfect qualities, it has high corrosion-resistant stability, as well as excellent electrical and thermal conductivity.

Without saying anything else, simply covering cold weapons with a layer of gold gives them a strong anti-corrosion ability.

Sometimes, when they used cold weapons to kill zombies, the fluids from the zombies were somewhat corrosive. Stabbing a zombie's head multiple times, naturally, the higher-quality alloy spears wouldn't be affected, but most other cold weapons would easily corrode from frequent use.

Many collaborators were a bit excited when they heard Old Bi say they could exchange other things for food.

Even though it's hard to find food outside now, other things should still be available.

However, when they heard that one pound of gold could only exchange for two pounds of food, they realized that even exchanging other things wouldn't be easy.....

Before the apocalypse, there were only tens of thousands of tons of gold worldwide, and just one or two thousand tons in national reserves, distributed across various locations.

A large gold and silver jewelry store might have thirty kilograms of gold, which was considered a lot.

Gold was generally calculated by grams, with one pound equaling 500 grams. Who would calculate it by the pound?

According to the pre-apocalypse gold price, a gram of gold was about 500 yuan, and a pound was about 250,000 yuan, whereas the pre-apocalypse food price was 6 yuan per pound.

By comparing pre-apocalypse gold to food, one pound of gold could buy 20 tons of food, but now it could only be exchanged for two pounds of food??!

Aside from gold, the list also included some items they were not familiar with, which came from the needs sent by Old Dong, Kong Shuang, Bai Jie, Zhou Weiguo, An Ya, Meng Yu, and others from the Big Camphor Tree Base.