From flint to the industrial revolution in 2 years: rebuilding civilization (after a zombie apocalypse)

The world has collapsed in a zombie apocalypse. You and a band of 500 other people (around 200 of whom are able-bodied) have escaped to a safe haven somewhere, and are tasked with rebuilding civilisation. There are still people outside in the real world, but if the zombies find out about your existence, and when they get to your location, they will attempt to destroy you.

Day 1

You don't know where you are, what date it is, or the time of the day. You start with nothing but your intellect, knowledge and observation. And some flint and pyrite, because come on.

It's sunny. The sun isn't directly up, but close. The ground is partly covered in snow, but there are some green trees, and partly-frozen freshwater lakes. The cold is pretty bad. You can tell that the temperature is at most -10 C.

• Tasks: protect from cold, avoid dehydration, avoid hunger.

It will probably take 30 minutes to get everything in order and have people listen to your directions. Use the flint and pyrite to start a few dozen fires and torches. You guess from the position of the sun that it's noon and the cold's about to get worse. You'll want some animal skins, but you'll need to make tools to kill some bears or whatever. You want to boil the lake water before drinking it, but you'll need a basic pot.

You can make a stone tip within half an hour, but you'll need rope to fasten it to a stick to make it a stone-tipped spear. Making a rope is easy, since you have plenty of sources of plant fibre. You can also use the stone tips to chisel out a basic pot from a rock. Boil some water and keep hydrated and warm. It's fine, you can drink boiling water.

So in 2 hours after landing, you have weapons and a pot. You can now hunt. You find mooses. Two mice (mooses) should be sufficient to feed 500 people, and you can use their skins as warm clothing  -- you might have to pass the skins around a bit, but congratulations -- you managed to survive the night.

• Inventory: fire, torch, stone spear, rope, spear, basic pot, boiled water, meat, animal-skin cloth

Days 2-4

Based on the fauna you've seen, atmospheric temperature and the fact that you had a night, you realise that you're in the Northern hemisphere, although quite a bit south of the arctic circle -- probably in Canada or Siberia. From the positioning of the sun and from the temperature, you figure you're just after the winter solstice. You also have the directions figured out approximately.

• Tasks: protect people and items from animals and elements, improve tools

It would help to start by developing some more simple tools, like: stone axe, stone shovel, bow and arrow, basket, which are already within our technological capability. We also need better pots, which are easy to make (separate soil, mix some sand into wet clay, shape it and fire it in a closed environment, like a kiln).

For residence, it might initially be better to create a dug-out to quickly house such a large number of people.

It's time for some division of labour.

• Division of labour: hunters (~14%), builders (~16%), lumberjacks (~20%) | artisans (~10%), maintainers (~40%)

(The tasks before the "|" are restricted on basis of physical capacity.)

The maintainers do tasks like providing fresh water supply, making and maintaining fires, cooking, cleaning, nursing injuries. The artisans make and repair tools (especially arrows) and pots, process carcasses for meat and clothing, and tailor. The artisans and maintainers should be observed by a trustworthy superintendent.

The hunters should also start surveying the lands they visit to create a mental map of the area, of the animals, plants, stones and other materials in the area, etc. Perhaps start thinking of temporary simple sources for stuff like writing material, ink, etc. before the perfected industrial products are developed. It's also important to look out for potential future locations to build mines.

The builders should find an area with a suitable geology and start digging a dug-out, on some land with relief to prevent getting flooded.

Obtaining wood has other positive effects -- you're also clearing out the forest for later agriculture.

Bones should also be stored, and bone weapons of the existing tools should be crafted and experimented with to find the best tools for each job.

• Inventory: fire, torch, rope, stone/bone tools (spear, axe, shovel), wood, basket, kiln, pot, dug-out, bow and arrow, boiled water, meat, animal-skin cloth 

You've probably had a few deaths at this point from animal attacks, human conflict and perhaps even from disease or accidental injuries. Remember to worry about hygiene, particularly dental hygiene. You would also certainly have had some crime by now. Build a small vertical prison (from which someone must be pulled out or climb out of) somewhere in the dug-out. A few hunters should take shifts as prison officers (to imprison people and guard prisons).

Days 5-15

You urgently need some plant-based food, and your hunters have hopefully identified something edible growing in the wild. You have been able to find some fruits (berries), and trees that you can get some syrup from.

But we really need to reduce the dependence on hunting and gathering to free people for productive urban tasks, which will be the first step towards an industrial civilisation. But agriculture remains far away, as there are no grains and cereals in the vicinity.

• Tasks: diversify food sources, start long-distance exploration

You know that there are cereals in the South. You've already figured out if you're in Canada or Russia (based on the flora and fauna you've found) -- if you're in Canada, you can find maize and sunflower from Southward expedition; if you're in Russia or Northern Europe, you can find millet, barley, wheat and hemp from Southward expedition. If you're in South America, you can find quinoa and plenty of other crops from Northward expedition.

The only problem is: going there on foot will take months. Fortunately, wherever you are, you can probably easily find wild horses, which will allow you to complete such an expedition in a week.

So let's prepare for the journey. You need to tame some horses, of course, and stock up some food for people and horses. They'll also need ropes to leash their horses, flint and pyrite and pots to boil water in (and to carry grain back in). Send a trusted superintendent with the explorers to make sure they don't wander off or decide to not return.

You should also look into expanding your food sources into the aquatic realm. Spear-fishing and net fishing are the most practical options at the moment, but it will be helpful to make a raft, which you can do with logs and rope.

At this point, your hunters (and explorers) should really have identified locations to build important mines and quarries: clay pits, limestone quarries, iron ore mines.

• Division of labour: explorers (~10%), hunters (~14%), lumberjacks (~20%) | gatherers (~20%), fishermen (~10%), artisans (~10%), maintainers (~16%)
• Inventory: fire, torch, rope, stone/bone tools (spear, axe, shovel), wood, basket, pot, dug-out, bow and arrow, boiled water, meat, animal-skin cloth, raft, net, fish, fruit, syrup, tamed horses, grains

Your explorers are back! In just a fortnight, you passed through the entire paleolithic phase of human history.

Days 16-135

It's the agricultural revolution! Well, at least if you have sunflower, barley or wheat. Remember to plough and irrigate your fields.

• Tasks: sow seeds, capture animals for farming, mine metals, build a city 

With all the forest-clearing, you probably have a lot of edible animals frolicking on your lands. Great, have the hunters capture them -- but to capture them, you need to build a fence from wood and stone.

We definitely need to improve our tools. The main advances here will be the use of bricks and the mining of metal. Making fired bricks is easy, and can be made from firing a mixture of clay and sand in a kiln. 

But we also need mortar -- lime mortar is probably the best you can do for now. Limestone is abundant (10% of sedimentary rocks are limestone, and cave systems are full of it) -- build a limestone quarry, mine some limestone (calcium carbonate) and heat it in a kiln to produce lime (calcium oxide).  A mixture of lime and sand in water gives you the lime mortar you need.

Iron is perhaps the most "complicated" metal to use, nonetheless its ores are much more common than the copper and tin required to make bronze. Since you have unlimited knowledge, smelting it is not an issue. You'll have to look out for "banded iron formations", the most common source of iron ore, specifically magnetite and hematite. 

You'll need to add charcoal to your bloomery to keep temperatures high, which also has the nice effect of carbonating your iron. Charcoal can be made by burning dry wood in the absence of oxygen, such as by covering it in clay and stone (so instead of actual combustion, you have a reduction reaction that removes the hydrogen and oxygen from the wood, leaving only carbon).

Then build a bloomery -- a pit or chimney filled with burning iron ore and charcoal. Upon burning, you'll get sponge iron -- a mixture of iron and unwanted material called slag. The sponge iron is then re-heated and hammered, driving out the slag and producing wrought iron. 

Our processes are getting quite complicated, and are best organised by building a city (or proto-city), with dedicated purpose-fit buildings. We can do this with our brick and mortar, and a ladder (which you can make with wood). The hardest part is making a rain-resistant roof. There are many methods here, but the simplest way is to make a wooden framework for the roof and place ceramic tiles on it.

We can also afford some luxuries now, like furniture and ceramic cutlery. These will be made by the craftspeople and carpenters respectively, while the weapon-crafting job is passed on to the smiths.

It's the urbanisation revolution!

All the transportation of resources between your mines and your settlement would benefit from a systematic transportation system. Have your builders level the terrain and pave some roads with brick and mortar. It's also time to reinvent the wheel (you can do this with wood) and make some carts. Perhaps all these carts and ladders and what not would be best made if you used some nails and a hammer.

Here's a summary of the buildings you'll need, classifying your inventory:

• City: 
• Urban buildings -- houses, public building, hospital, prison
• Mines and extraction -- forest, water bodies, farm field, farm pen, horse stable, clay pit, limestone quarry, iron ore mine
• Factories and processing -- butchery, kitchen (including water purification, fire), mud processing, charcoal kiln, masonry and lime kiln, pottery kiln, bloomery, smiths, crafts centre, general repairs, tailor, carpenter
• Storage -- grain and meat storage, water tank, materials reserve, general tool storage, weapon storage, cart shed
• Transportation -- roads, tunnels

(Examples of stuff in the general tool storage: flint and pyrite, rope, ladders, cutlery items, carpentry knives, wheels, nails, hammer. Examples of stuff in the materials reserve: wood, iron, clay)

It's also time to rewrite our division of labour, specialising the artisans to specific tasks. With the advent of plant-based foods, cooking has also become more complicated, and should require separate specialised labour (but they can manage the water-boiling too), so the maintainers just maintain fire. The farms need constant tending to -- for irrigation, feeding animals, applying dung fertilizer to plants, etc.

• Division of labour: explorers (~4%), lumberjacks (~7%), builders (~9.2%), guards (~2%) | gatherers and fishermen (~25%), plant farmers (~5%), animal farmers (~5%), potters (~3%), transportation workers (~6%), iron-smelters (~2%), smiths (~4%), carpenters (~5%) masons (~5%), craftsmen (~5%), butchers (~2%), tailors (~4%), cooks (~3%), nurses (~0.6%), cleaners (~0.4%), fire-maintainers (~0.8%)

The civilisational advancement in this phase is incredible and actually quite rapid, but our reliance on gathering places a heavy strain on our labour pool (we especially need more builders).

For example: with all these reserves and supply chains to care about, we really need to start recording and documenting. But making paper will need mills to grind wood, and so on.

But all this is about to change with your first harvest.

Days 135-720

With 125 people freed from gathering and fishing (fishing is no longer a necessity either, as you now have plenty of diversity in food), you are ready to systematise your supply chains. You also note that maintaining a complicated supply chain comes with a serious issue of incentives, where a few nodes slacking off disrupts the entire system. You need to privatise services and allow some primitive market to set incentives.

You also begin to observe that our small population places a serious strain on your ability to make things -- certainly, you cannot build an industrial civilisation with this population. We really want an industrial civilisation -- we want things like electricity, cars, computers, modern medicine. We want to shorten the workday and allow people to transition into more interesting jobs. You will need immigration, but making contact with the outside world remains dangerous. You need to prepare.

• Tasks: organise your supply chains (mills, paper, ink, records, clocks, cats, evaporative refrigeration), improve materials and systems (steel, cement, mechanization), prepare for contact (defense)

It's the iron age/classical age. You may argue that we already entered the iron age in the last phase, but with the exception of the use of iron, it was pretty much a bronze age civilization until now.

Before anything else, we need to make sure the grain we've harvested stays until the next harvest. If you have rats, domesticate some cats. If heat is a concern for storage, make an evaporative cooler (self-explanatory).

To be able to make and maintain records, you need paper and ink. The easiest way to make ink is to mix charcoal ash with water.

To make paper, you should best institute a pulp mill -- a factory to grind wood into fibres. The technology of a mill is used for a whole variety of applications, such as grain processing (so you can now cook bread) Once you have a pulp mill, the pulp just needs to be thinned and drained on a mesh, then pressed and dried.

An improved version of a chimney bloomery can be created by adding paper bellows to blow air to remove impurities during the process. You should also experiment with different levels of carbon content in the product to perfect your steel-making.

Institute a few superintendents to the factories to maintain stock quantities and demand estimates to allow flexible allocation of labour and resources.

Clocks, which will be useful for improving efficiency with regards to the workforce, can be made easily in the form of sundials.

Your construction material needs serious updating -- it's basically in the neolithic age. Have your explorers visit some volcanic areas for various volcanic deposits -- some of them will turn out to be pozzolans -- mixing these with calcium hydroxide (which you can get from lime and water) gives you lime cement -- which when mixed with sand and gravel gives you concrete, that can be used a mortar. If you need to build anything in water for some reason, add volcanic ash -- this has weird reactions with water which will allow it to set underwater.

Many of your activities can be partly mechanized with water-power -- e.g. mills and bellows. Build a water-wheel -- this is just a wheel you put under flowing or falling water, with hanging cups to capture the water's energy for rotation. It can then be connected to a trip-hammer, which would simplify and reduce labour-dependence in many manufacturing operations.

Defense plan

Let's make a defense plan for your base.

First of all, every commercial building should be equipped with a dug-out shelter with a narrow entrance, from which all the functions of the building can be carried out. These shelters should not replace the existing buildings, as they can act as death traps if blocked or poisoned.

An underground network for the dug-outs is required, but should be difficult to traverse and the network links should be minimal. The idea is that these tunnels should only be used if temporary circumstances make it dangerous to come to the surface. Therefore only factors of production whose supply is required in the short-term should be linked to their factories. Each dug-out should store flat-boulders (both round and flat-based ones) to clog the network if needed.

Homes should not be fitted with individual shelters -- instead, a large communal cave should be prepared with basic residential facilities fitted (you can just the dug-out you prepared when you were starting out, and expand as need be). This is to prevent having too many entrances to the underground network (unconnected private shelters are fine, but it's easier to just escape to a commercial area or the communal home, as the area is still pretty small).

Allow surplus to build up in the storage: your factories will very likely be attacked. This is especially important for your grain storage, as you will not be able to take your fields underground.

Let's consider the three routes that the zombies will attack you from:

• By land

Preparing for the worst, suppose that the zombies have tanks, and massive numbers of soldiers. I suggest a haphazard perimeter of secret land mines around your settlement. 

But these should be the last resort, in that you should be able to disable the attacking forces before they reach this perimeter (because the land mines are not easily replenishable). Build fire-towers around this perimeter to destroy incoming armies with rockets, oil and flamethrowers. Towers should be fitted with supplies of everything needed to sustain your warriors. 

The most reliable way to hijack a tank, however, is to hijack it. So I suggest heavily-armoured warriors with pickaxes to hijack tanks that get through your defenses, then use it against other incoming tanks. 

Any strategic mountain passes should have their boundary mountains converted to fire-towers. 

In case of any penetration, station some firearm-equipped warriors within the city to destroy any intruders.

• By sea

Rig any nearby waters with jagged rocks. The previously mentioned "marine cement" is relevant here.

• By air

Surface-to-air missiles are not really feasible at this stage of development against any reasonably fortified aircraft. Instead, you'll have to focus on fortifying your city. Make your buildings out of steel, and cover them with thick layers of steel wool to absorb impact.

A central watchtower should be instituted to check the progress of your battles.

Training is essential -- train your warriors for aim, matchlock operation, combat and formations in tank-hijacking. Train civilians in emergency protocols such as seeking shelter and blocking pathways.

Consider "wheeled" towers to be able to quickly focus your resources on a spot -- this will be useful if the zombies attempt to pressurize a specific spot of your defense.

So the new technologies we need are:

• Saltpeter: Saltpeter can be mined from your limestone caves, from bat and bird guano. If you are near Chile, the Chilean Atacama desert is a major source of these deposits. It is purified by boiling it with a small amount of water (which dissolves the saltpeter, leaving impurities as residue), then pouring the solution through wood ashes (which contain potassium carbonate, allowing these carbonates to bond with dissolved calcium and magnesium ions and precipitate out), before drying. 
• Sulfur: Your best bet for sulfur is from heating pyrite. If you have salt domes of sulfur in your region, go for them. 
• Gunpowder: A milled mixture (mixed wet, then dried) of saltpeter (75%), charcoal (15%), sulfur (10%). Burning saltpeter is what produces the propulsive power (and it doesn't require much oxygen, because it produces its own when burning), charcoal is the fuel, and sulfur is also a fuel but also reduces the ignition temperature of saltpeter. 
• Land mines: The only reliable way to build a gunpowder landmine is to simply bury patches of gunpowder lightly under the ground and shoot flaming arrows at them. To prevent the powder from getting moist, consider covering it with oil or concrete or something. Do some tests.
• Rockets: These are just gunpowder-powered arrow-launching cannons.
• Matchlocks: Matchlocks are perhaps the best firearm you can equip your warriors with at this stage. They operate via a lever mechanism that lowers a slow match into a constantly lit flame, transmitting it to the gunpowder. 
• Oil: Find crude oil. 

That's it. You are now on the verge of the first industrial revolution. By sending explorers to nearby regions, you should recruit a labour force to build more and larger mines for oil and metals, to mass-produce on assembly lines in factories, and to build larger and more ambitious engineering projects such as power stations and electrical grids. Your growing population will itself create its own demands, such as more housing and food, better sanitary practices and medicine and efficient mechanization of processes with steam and electricity. 

But by now you know the drill.