Simurk, The Pits of Iron Dust

Simurk is a town through some mountains, in a desert. It links to various interesting places, but isn't really a 'frontier' town. Dusty donkeys carrying buckets of slag and rock are driven here and there, and the winds blow dust from the mines everywhere.

Veil+turban is referred to as a  tagelmust or a litham

They have big open strip mines with descending layers that get darker and weirder as you descend because of course they do. Simurk has been digging for a very, very long time.

The most prominent pit is huge. A village could be dropped down it, and that's exactly what the people of Simurk did.  The first two layers are farmland- protected from the winds of the desert by ducking below them, and fueled by animal dung and terrible, terrible soil in which very hardy plants eke out a living. These farms do not feed Simurk, they only flavor imported foods. Bitter spices and ornamental desert flowers are all that can survive on the levels of the mines.

The third layer is Lower Simurk. Contrary to what you may think, this is the richest and most fashionable district- nobility and merchant princes of Simurk are happy to live here- they are close to the riches of the earth, there is plenty of shade from the glaring sun, and roving bandits and monsters from the desert typically just bully the lower-class citizens who live above ground rather than descend into the pit.

Then, there are TWO pits within this pit, descending 4 more layers. Why are there two pits?

1. The owners of the great pit were once one family, but jealous heirs refused to rule jointly and split the pit down the middle, one mining on one side and the other on the... other.
2. Originally, there was only ever going to be one pit. But they dug up something atrocious, sealed it away/made an infernal pact with it/ignored it and started over on the other side.
3. One pit ran dry of resources and was abandoned to become a scummy underhive.
4. One pit hit groundwater, and is now a revered source of water. Or a wretched sewer.
5. One pit started being used as an easy place to bury people but now mining can't continue due to all the tombs that crowded out the mines. Some mine illegally within the tombs though...
6. No real reason, that's just how the digging turned out due to the buildings of nobles getting in the way of full excavation. 

Most pits have at least one bridge every two layers or so. They are as wide as a street and frequently have

1. Vendors hawking food, drugs, sex, and other temptations to tired miners and anyone else
2. Thieves out to snag choice bits of ore from exhausted and distracted miners
3. Pressgangers out to snag slave labor for shady merchants
4. Toll collectors who have a legal right to 1% value of items crossing from one side to another 
5. Mine inspectors on the lookout for bad construction or shady murderhobos
6. Workers on strike due to some horrible occurrence or other in the mines

 Lesser bridges of rattling wooden planks are less common, as it's hard to push a mine cart across such a bridge, but these rickety suspension bridges do exist in  the lesser pits but have far fewer  ancillary characters lurking about.
As for products and plothooks and people of Simurk (presented in ghastly organization for your displeasure)

1. Simurk Steel- Reliable, sturdy blades of quality ore. They do 2d3 or 2d4 damage instead of swingier d6 or d8, though unless you have a trustworthy buyer, you may get a poor quality version that does 2d2 or 2d3 for d6 or d8 weapons.
2. Kohl-Eyes- Men and women with blood like ice and way too much dark eyeshadow can be hired from the mines to perform all manner of despicable acts like assassination, tomb-robbing, extortion, marriage, etc. +1 Morale compared to regular hirelings, but -1 Morals. Also less talkative and fun and more stoically sinister then the average no good henchman.
3. The Hanging Prisons- Rather than use any of the hundreds of dank corridors the mines provide, the preferred form of imprisonment is to dangle criminals in iron cages from the sides of bridges for public shaming and agoraphobia. For a fee, they can be hauled up by burly bridge-guards and talked to or even bailed out. A good place to throw NPCs who haven't been seen in a while.
4.  The Worm Oubliettes- But those hundreds of dank corridors DO sometimes have a prison cell at the end, or a simple hole with a prisoner at the bottom, where the deeply unfortunate are kept in pitch black cells to rot and choke on mine dust. The logistics of a prison break could be quite an adventure with all the ascending and descending.
5. Nightshaded Tea-House- A classy establishment where the tea is rich, bitter, and occasionally poisoned, just to keep the riff-raff out without having to inflate prices. Those with appropriate antidotes or just a gambling attitude may have meetings with assassins, necromancers, and other unsavory but well-mannered individuals who will likely be in a position to propose, fund or assist 'business ventures' of highly illegal nature.
6. Dowsing Oracles- Provided you are looking for places to dig for water or ore, you can hire a blind oracle to tap around with a wiggly stick and provide valuable dowsing services. Their prices are sky-high, but for the right hidden treasure, it just might be worth it.
7. Freelance Mine Inspectors Needed- Those answering want ads can be sent into dangerous forgotten mine tunnels to update records on the state of the mines. See 'What's Wrong With This Tunnel' for examples of what excitement awaits. Rewards vary.
8. Helldiver Owl- Small canaries are sometimes kept in cages to provide valuable warnings about bad air in mines. Falcons can be trained to aid in hunting small game and perhaps even warfare. Helldiver Owls are supposed to fill both niches in the mines of Simurk, and while they aren't trained to attack humans, they are trained to extinguish light sources and fetch small objects and hoot in alarm if set to watch over sleeping people. They're not easy to manage and cost a small fortune, but hey.
9. Simurk Lost and Found- In addition to retrieving people's camel-keys that fell off a bridge to lower mine levels, Simurk Lost and Found rewards people for turning in lost items, and sells these lost items to the rightful owner if possible and to anyone with gold if profitable. Definitely a law-abiding organization and not a cheeky den of thieves.
10. Gravers- under the disguise of being freelance miners, Gravers can supply treasure maps to suspected tombs full of treasure. Sometimes these 'tombs' are 'residential houses' but it's all a matter of how you look at it, eh? Gravers sell great pickaxes and tortoises.
11. Shaders- In Simurk, it can be very fashionable to have a veritable shield-wall of people with umbrellas keeping the sun, wind, and sand off of you. Having people accomplish this with KITES is even more fashionable, and as such there are kites and umbrellas that are works of art, valuable in their own right, and a sure sign of wealth is an approaching phalanx of embroidered silk umbrellas advancing across a bridge, or a fleet of kites blocking out the sun, all likely decorated with paintings of landscapes, animals, etc that, when properly viewed as a whole, depict the face of the shaded one. Kites blown by the wind can be the subject of frenzied treasure hunts. 
12. Crystal Fountain- Normally dry, this fountain is activated via slaves pumping away in the depths of  Simurk. Anyone is welcome to gather up their friends and search for the pumps, but the journey to them is quite perilous due to the mechanism being in an old abandoned mine. It is quite beautiful when active, and reaction rolls are made at +1 near it when it is active. It is a famous spot for proposing marriage, making peace treaties, and other portentous events.

SO WHAT'S WRONG WITH THIS TUNNEL(1d6, +1 per depth)

1. It's just totally devoid of anything valuable to mine and coming here was a waste of torches.
2. Some low-income citizens live here.
3. Some citizens were buried here, possibly with grave goods.
4. It's a collapsing mess. Going in means you'll probably have your exit cut off and have to delve deeper to escape.
5. It's full of poisonous vermin like snakes, scorpions, etc. Or maybe some burrowing monster.
6. It was a tunnel dug by criminals to access a merchant's basement.
7. It's a Worm Oubliette and the prisoner is so top secret even being here is probably punishable by death. May or may not be a Man in an Iron Mask.
8. It's a criminal hideout and they aren't pleased at their secret being out.
9. It's full of bad air and probably dead people. Poison, slow asphyxiation, or explosions possible
10. Some rich dude was buried here and despite making a whole tomb of the thing, was forgotten 
11. Tunneled into an inevitable forgotten cursed dungeon/cave system of inhuman precursors
12. Dug up something REAL BAD

REAL BAD THINGS (That aren't mega monsters. I wrote up like 3 and decided they were terrible. I don't think this is much of an improvement)

1. Wishful Ring- A simple golden ring inscribed with god-runes that anyone, even the illiterate, even the blind, can read. The ring reads 'Tell Me What You Want.' Grants the wearer's spoken wish, then teleports to the finger of a random person within 100 miles. Can absolutely be re-used if you catch it again. Everything in creation may war in pursuit.
2. The Midas Well- Ominous rumbling and rushes of molten gold flow, first slowly, but eventually building up to a continuous geyser a hundred feet high. Over the next few days the entire pit fills with gold. Gold rains from the sky as it spews forth. It'll have formed a mountain in a few months. Gold becomes worthless and economies crumble. Empires will fall if something isn't done about this.
3. Ancient crypt full of plague spirits/rats/zombies. What plague? THE plague.
4.  Hella Cursed Mega Doom Sword
5.  Ancient Ifrit who grants you three wishes and will grant them in ways most likely to destroy the world
   
6. An ancient book of unreadable script, illustrations of heroic figures and monsters, and arcane numerology. Until this cursed artifact is destroyed, your campaign must be run in GURPS 4th edition

If you don't have the rules for GURPS just roll a 3d6 instead of a d20 and demand combat rounds be 1 second long and strive for realistic limits on what can be accomplished in one second

WHAT ELSE CAN YOU DO WITH SIMURK
One thing you could do is ruin it. Turn it into a sprawling megadungeon infested with monsters that it's terribly easy to descend deeper into. You could half-ruin it and make it a warzone between dead from the crypts and the remaining living cowering in their houses. Or between an invading army on the surface and the curious defensive position of the Simurks being literally 'holed up.' Or between an awoken dragon from the depths, coiling and huge.

You can change the theme from sand and mines to flowing waterfalls and elegant trees in a network of sinkholes, or make it a sulfurous caldera of geysers and hot springs. You could have Simurk be in contact with underground civilizations from the veins of the earth.

You can sell the players a giant hole in the ground and see what they do with it and then shout 'No, [playername], you ARE the dungeonmaster' at some point.