Having made up their minds, Lu Zhe and Shen Bing started looking for a suitable place to dig.
Lu Zhe looked around: "First of all, it can't be too far from the camp! Otherwise it would be too tiring to carry things back and forth."
Shen Bing nodded: "You're right. Luckily there are many hills around the campsite, so let's choose from among them." Then she pointed to a gravelly hillside: "Hey, what about over there?"
"Let's go check it out!"
The two walked over to the hillside. Lu Zhe stabbed his paratrooper knife into the ground, dug out a rock, and the surrounding soil also loosened. He scraped around a bit, the mud trickled down.
He shook his head: "Too many pebbles, the soil quality is also unstable. If it collapses, we might get buried."
Next they inspected a small verdant hill. The soil was loose with serious seepage that could also easily collapse!
They also checked out a shale cliff that looked sturdy, but rock layers formed during different periods had uneven toughness and could easily crumble under external forces!
"So the most difficult problem to solve when digging caves is collapse!"
Lu Zhe said somewhat regretfully: "You're right. There's no special structure like the bear cave here. If we insist on digging out a cave, we'd have to install collapse anchors and supports at any time, and build voussoir arches out of bricks and clay, pretty troublesome, and still not necessarily safe."
"Unless we find a similar structure to the bear cave?"
"Not necessarily..."
Lu Zhe noticed the rock mountain near the banyan tree.
It wasn't a mountain formed from piled up rocks, but a single gigantic boulder itself. On three sides it was embedded in the earth slopes overgrown with vegetation, unclear how big it was. Bird droppings on the top allowed lush bushes and moss to grow. Only the 30 meter high southern rock face was exposed.
Lu Zhe walked up to the rock face, placed his hand on it, and information about it streamed into his mind!
"Formed 1.1 billion years ago in the Mesozoic era as granite, main components silicon dioxide, calcium carbonate..."
"Hey Sis Bing, do you know about the Ancient Cliff Dwellings?"
"I know of them but haven't been." Shen Bing stared blankly for a moment.
"Could it be... you want to carve caves out of this rock?"
Lu Zhe slowly turned his head: "Why not?"
Shen Bing was astonished:
"Of course not! This rock is so hard! If you want to carve out a storage room, it would take five, seven, eight years at least to finish!"
Lu Zhe shook his head: "It looks difficult, but actually won't take that long! And once we carve out space here, it'll be like having a fortress! No monkeys, crocodiles, storms or tidal waves can do anything to us."
Shen Bing felt it unbelievable: "Lu Zhe, carving storage rooms out of a cliff face is practically an impossible task for us."
"Why do you say that?"
"The rock face is too hard, and we don't have modern tools, how can we possibly carve it out?"
Lu Zhe smiled: "Were the Ancient Cliff Dwellings carved out by modern people?"
Shen Bing froze!
The Ancient Cliff Dwellings referred to nearly 100,000 square meters of artificially carved caves of varying sizes on a sheer rock face, with over a hundred chambers, an extremely spectacular sight.
The chambers had doors, windows, kang heating beds, stoves, horse mangers, cabinets, chimneys and so on. Some even had anterooms, like modern two or three bedroom units.
"That probably took thousands of artisans several years to complete right?"
"Mobilizing thousands for a few years just to build 100 some civilian houses? I don't think it's very likely!"
Shen Bing thought about it, and felt he had a point.
"Not only the Ancient Cliff Dwellings, there are cliff cave dwellings all over the country. As long as the methods are right, with just one month we can have an extremely sturdy chamber."
Of course Shen Bing knew what it meant if they had a stone house!
Ignore raging gales, fierce birds and beasts, pleasantly cool in summer and warm in winter, clean and easy to keep clean.
"You know how?"
Lu Zhe nodded: "A little!"
"Could it be you're descended from ancient stonemasons?"
"No, there were relevant descriptions in The Why of Everything."
"Lu Zhe, I'm getting more and more curious about your The Why of Everything. When we get back, you definitely have to give me a set!"
"Um... what if it goes out of print?"
"Such a good book, how could it possibly go out of print?"
"Who can say for sure? I think the 16 Character Yin Yang Feng Shui Secret Art is pretty good too, but that still went out of print!"
Shen Bing placed her hands on her hips, widened her eyes, and her chest heaved: "Humph, then lend me your set to read!"
"Oh, is Sis Bing so cute when angry?"
"Cut the crap!"
Lu Zhe nodded: "Sure, I'll definitely look for it properly when I get back!"
"Alright, enough kidding around! Really, how long would it take to carve out a chamber?"
Lu Zhe recalled that a surname Lv stonemason descendant had said on the 10th CCTV documentary that carving out a 20 square meter chamber didn't require very advanced skills. Five stonemasons working for about a month could complete it.
Right now, Lu Zhe's strength was around ten times that of normal people. Just in terms of work efficiency, one of him was worth three or four people, plus the girls' assistance, it shouldn't be worse than five stonemason's efforts. Conservatively, around one and a half months should be about right.
"Including making the tools, around one and a half months."
"Making what tools?"
Lu Zhe thought about it: "The main tools are rivets and iron pry bars, and hammers!"
"We don't have any of those!"
"We don't, but there's no need to worry. These tools are very crude, and can be made completely from what we already have."
"Keep making tools huh?"
"That's right, process the iron ore, smelt iron. And this time, we have so many pull carts. Many pull cart materials can be used to make bellows to improve iron smelting efficiency!"
Everything Lu Zhe said, Shen Bing didn't even dare imagine, yet hearing him state it so matter-of-factly, it was as if it were all a given!
She felt like there was no difficulty in this world that could stump the youth before her.
"Then... start now?"
"Yes, let's start now!"
After finishing speaking, Lu Zhe began making bellows!
It sounded difficult, but was actually very simple if you had the concepts, and everything could be done with materials on hand.
He disassembled some spokes from the bicycle wheels to use as pliers, bending them into 5 cm segments.
He also split twenty or so 40 cm long, 5 cm wide bamboo strips to make the bellows frame.
Second step: he punched holes in the middle of each pair of bamboo strips and strung the spoke segments through to act as a simple bearing.
The two bamboo strips were now fixed together but could still spin freely, forming an "X" shape.
Third step: three "X'"s were joined end to end to form an "XXX" group. Two groups were made.
Fourth step: some sailcloth was torn off and glued onto the two "XXX" groups with tree resin. This formed square cylinders!
Fifth step: the ends were sealed off with bamboo strips, one end made into a handle, the other fitted with plastic boards to make the air outlet and valve!
The two valves had one sitting on the outlet, allowing air to only flow outwards, while one covered the bottom inlet, only allowing inwards airflow.
When pulling, air was sucked in from the bottom inlet. When pushing forwards, the air would be forced out through the outlet into the furnace!