Seeing this situation, Lin Feng couldn't help frowning. The rock in front of him was so hard, he hadn't expected it before.

After carefully observing the rocks in front of him, Lin Feng found that it was indeed a little different from what he had dug before.

The stones he had dug before were all cyan, but the rocks in front of him were blue and silver. Touching it with his hand, Lin Feng felt a coolness coming from the stone.

At this time, Lin Feng noticed that the energy fluctuations around him were almost twice as much as before. Although it was still relatively weak, as a level 7 cultivator, he could indeed detect it.

In a fit of rage, he increased the injection of energy in his hand, and Lin Feng operated the electric pickaxe towards the rock in front of him.

"Dang!"

When the pickaxe hits the rock in front of it, it not only fails to shake off a piece of rubble, but shatters the pickaxe directly.

It's so hard!

Seeing the scene in front of him, Lin Feng couldn't help but open his mouth wide.

Although the electric pickaxe is said to be an ordinary wall demolition tool, it is specially designed for this kind of work, and its pickaxe head is made of professional materials. It's not indestructible, but it's also very hard.

And the pickaxe shattered directly after hitting the rock in front of him, which means that the rock is too hard.

Lin Feng touched the rocks on the walls on both sides with his hands, and found that it was different from the one in front of him, it was still the kind of stone he had dug before.

Could it be that a particularly hard rock in front of you is blocking the way? Lin Feng said secretly in his heart.

Back at the entrance of the cave, Lin Feng retrieved the two pickaxes again, and then returned to the small hole he had dug again.

Changing to a pickaxe, Lin Feng dug towards the wall next to him. A large amount of rubble fell from the wall, and Lin Feng wanted to bypass this solid rock.

But an hour passed, and Lin Feng finally found to his chagrin that this seemed to be more than just a solid rock in front of him. He spared a full ten meters and found that no matter where he started digging, he would eventually encounter the same hard rock as before when he had advanced to a certain point.

Lin Feng found that the kind of hard rock that was exposed at the ten meters he was circling seemed to be connected together. The surface is smooth and hard, with no faults at all.

Could it be that this is a separate wall? Such an idea suddenly popped into Lin Feng's mind.

In his original world, the underground vaults of some banks were designed this way. The vault was built underground and surrounded by heavy walls made of hard steel and other materials. It would be impossible for some robbers to dig a hole in the ground to get to the vault and steal money, they would not be able to penetrate the hard outer wall of the vault.

And the scene in front of him was a bit like the kind of vault in Lin Feng's previous life, except that it was not made of metal, but a solid stone.

Thinking of this, Lin Feng wanted to know more and more what was behind this hard wall. Now Lin Feng had a feeling that the hard stone in front of him was not naturally formed, but artificially made.

Because of the continuous excavation of a width of ten meters, Lin Feng could easily see the barrier in front of him, which was about ten meters wide and more than one person high.

Lin Feng found that on the surface of the huge stone in front of him, in addition to being very smooth, there were also some traces left by human tools. There are some small scratches on the top of the wall, which should have been left by the machine.

And Lin Feng experimented with the electric pickaxe in his hand to touch the stone in front of him, but he didn't leave the slightest trace. That means that these lines were not caused by him, but have been left behind a long time ago.

However, Lin Feng didn't want to give up like this, he had been digging here for seven days, and he couldn't give up because of a hard barrier. If there is really anything good in it, it may be seized by those in the mountain forces. Lin Feng wanted to enter the mountain before they discovered this secret.

Putting down the electric pickaxe in his hand, Lin Feng took out the Xuantie bayonet from the supermarket from his waist before. The bayonet is said to be made of black iron, so it is also very sharp.

Carrying sixty percent of the energy in his body, Lin Feng injected it into the dark iron bayonet in his hand. Without hesitation, Lin Feng slashed towards the rock in front of him with his knife.

"Boom!"

Under Lin Feng's powerful energy, several pieces of gravel were chopped down on the rock in front of him.

Looking at the Xuantie bayonet in his hand, Lin Feng found that there was no damage on the blade.

It seems that this weapon is still good, Lin Feng said secretly in his heart.

Since the Xuantie bayonet was able to chop the rock in front of him, Lin Feng no longer hesitated at the moment and continued to slash towards the rock in front of him.

"Bang ......"

As Lin Feng went down with a knife, gravel continued to fall from the rocks in front of him.

However, the rock was extremely hard, and it took an hour to cut the rock to the extent that it was one meter thick. It can be seen that the hardness of the rock is so hard that if it were to be changed, Lin Feng would be able to move forward a distance of nearly ten meters in an hour.

Since it had an effect on the rock in front of him, Lin Feng couldn't give up. Time passed little by little, and Lin Feng kept slashing the rock in front of him with a dark iron bayonet.

With each meter he advanced, Lin Feng felt that the energy fluctuations around him increased by one point. With such an effect, Lin Feng continued to carry out this work without stopping.

Another seven days passed, and during those seven days, the rats raised their demands on those who caught them. In a week, the depth of the hole dug by the others reached almost a hundred meters, but Lin Feng encountered the hard rock after digging for a thousand meters. For seven days, Lin Feng had only penetrated less than a hundred meters.

But despite this, Lin Feng's speed of digging hard rock was no worse than the speed at which ordinary people could dig holes. At this rate, other ordinary people will probably be able to hit that kind of hard rock if they dig for another two months.

However, they are all ordinary people, and electric pickaxes have no effect on hard rock. It is estimated that by then, it will be time for the mountain forces to use their cultivators.

But even then, they might not be able to dig hard rocks like Lin Feng, and the dark iron bayonet in Lin Feng's hand was something that was not available in this world. As for whether some other weapons had any effect on hard rock, Lin Feng didn't know.

On the eighth day, Lin Feng returned to his small cave as always, and he had been digging holes for half a month. After going a hundred meters deep into the hard rock, Lin Feng felt that the energy fluctuations around him were very active.

On this day, Lin Feng used the dark iron bayonet in his hand to slash the hard rock in front of him as usual, but with a sudden knife, Lin Feng stopped the movement of his hand.

Originally, he felt the strength of the feedback in his hand relax, but the next scene he saw surprised Lin Feng.

The hard rock in front of him was actually cut out of a small hole by Lin Feng, and a ray of light shone out of the hole. (To be continued.) )