question

[JohntaviousWilliams]

Why is quarry/ Construction mud deeper than river mud?

[QUICKSANDMAN]

From what I've gathered its because quarry pits were actually dug out in a deep area so they can fill it with as much sediment as they can after they extract what they are digging for. A river has a lot more variables too it because its always moving and always changing, and it has to have the right type of dirt/clay/sand mix or it just isn't a good sink. Sometimes it'll have a good mix but it isn't soaked in enough so it's all dry.

Pretty much one is pumped full of wet clay and the other depends on nature.

Thats my really brief take on it, I'm sure someone else has some better information than me though.

[HopelesslyStuckGirl]

There is a quarry I know of that I have been to a couple times and have had friends go there often. Also the owner gave a tour of the facility years ago. He explained that there are pits at the quarry that can be up to 20 feet deep due to how they are dug out from the start. The idea is when they filter the sand and the imperfections to get to their finished product, they need deep settling pits to accomplish this.
There are parts of the quarry that have large expanses of pure/perfect waterbed quicksand as a result. And then there are areas, usually in run off spots, that have thick clay and those are like tar pits. The workers call the stuff peanut mud because it resembles thick peanut butter. If it is an active quarry the place is usually infested with really good quicksand. Even if the weather is dry. This is because they pump water into the settling ponds to help with their process. So things are usually pretty soft and saturated. These places can be really dangerous as a result since things are alot deeper and looser.
Quicksand will form differently than in the wild and it behaves differently as well. Also never wear boots/sneakers around this stuff. You won't get out without being dug out since the suction created won't let you pull your feet up and you'll only go down. (Again, tip from the owner). Abandoned quarries over time will harden up and pack in where the quicksand will disappear. They will then overgrow with weeds and be good for only dirt bike riders eventually.

Hope this helps some. The physics behind it are pretty fascinating when you learn how the process works.

[quarrysinker]

There is a quarry I know of that I have been to a couple times and have had friends go there often. Also the owner gave a tour of the facility years ago. He explained that there are pits at the quarry that can be up to 20 feet deep due to how they are dug out from the start. The idea is when they filter the sand and the imperfections to get to their finished product, they need deep settling pits to accomplish this.
There are parts of the quarry that have large expanses of pure/perfect waterbed quicksand as a result. And then there are areas, usually in run off spots, that have thick clay and those are like tar pits. The workers call the stuff peanut mud because it resembles thick peanut butter. If it is an active quarry the place is usually infested with really good quicksand. Even if the weather is dry. This is because they pump water into the settling ponds to help with their process. So things are usually pretty soft and saturated. These places can be really dangerous as a result since things are alot deeper and looser.
Quicksand will form differently than in the wild and it behaves differently as well. Also never wear boots/sneakers around this stuff. You won't get out without being dug out since the suction created won't let you pull your feet up and you'll only go down. (Again, tip from the owner). Abandoned quarries over time will harden up and pack in where the quicksand will disappear. They will then overgrow with weeds and be good for only dirt bike riders eventually.

Hope this helps some. The physics behind it are pretty fascinating when you learn how the process works.

Quite techy indeed, thanks for sharing

[bogbud]

That's a really, really good post from StuckGirl. Well appreciated!

I've something to add about mud at rivers:
When you are inland are in a hilly area you can mostly forget about riverbanks as the waterflow is mostly too fast and any fine sediment is washed away. You need to look in flat areas and when it's near the coast it gets much better. The current has to be as slow as possible so that the fine stuff we need for mudbanks can accumulate. Tides effectively double the amount of sediment as it comes from two sides.
Look out for the banks in curves or secluded bays and the like:

curve.jpg

bay.jpg

There is still lots of trial-and-error involved. Anything between a rock-solid beach and bottomless quickmud and real quicksand is possible.

[beachbum]

There are a bunch of quarries around me that are off limits but I know contain deep mud/quicksand, and I pass by them frequently. Although tidal mud can produce some decent mud/quicksand, the conditions made by the man made quarries can produce all sorts of different types of mud as explained previously in this post. There is no way natural areas can produce the same conditions as digging a deep pit and then pumping sand and water in it.