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Is the world really running out of sand?

practical.engineering

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Re: Is the world really running out of sand?

#91

Post by emilecantin »

JoeAltmaier wrote: post #89

The whole idea of making your own sand is not sound. It will cost more, perhaps many times more. Seems clear when you think about it: hard to beat the cost of 'natural' sand because you just drive over and load it up. Add any more to that process, it's gonna go up in price. Including crushing rock etc - energy-intensive, then sieving. All add cost over and above, well, just hauling. And vague comments about 'couldn't…

Haven't read the article, but I watched the video. He goes on to say that it's not the full story, and he also does some tests where instead of optimizing for a particular water ratio in the mix, he optimizes for a specific texture when mixed, which is termed "workability". If you keep "workability" constant, you can put much less water in the mix, resulting in a stronger concrete when cured.

Re: Is the world really running out of sand?

#92

Post by ChuckMcM »

rootusrootus wrote: post #20

Every time I watch a practical engineering video I like Grady more and more. Great presenter, interesting videos, great value for the time spent watching. Gets right to the point in the first sentence, and the rest of the video is still worth watching. Add me to the long list of people who heard the bit about desert sand not being suitable for concrete and believed it. I'm happy to be corrected.

I love his book too. I ended up buying a copy for my sister who kept asking me how I knew all their weird details about things like sewer systems :-)

Re: Is the world really running out of sand?

#93

Post by zahlman »

moomin wrote: post #90
diggan wrote: post #13

Earlier quoted context omitted.

> and 70% of the world's supply comes from just one place in North Carolina A quick search seems to say there are more places available for getting that than North Carolina. Is it possible that this specific mine just happens to be the cheapest available right now, but in case they for some reason disappear, there are alternatives everyone would switch to? Or is the situation that if that mine disappears, there is no…

>> and 70% of the world's supply comes from just one place in North Carolina > A quick search seems to say there are more places available for getting that than North Carolina. I mean, I deduced it straight from “70%”.

I'm pretty sure the implied argument is that, while this source currently supplies 70% of the total, we aren't actually dependent on it - i.e. production could be scaled up elsewhere.

Re: Is the world really running out of sand?

#95

Post by samatman »

btown wrote: post #87
havblue wrote: post #78

Earlier quoted context omitted.

Meanwhile, the group "Led Zeppelin" also avoided the ambiguous spelling to prevent people from pronouncing their name "leed zeppelin". You can't win with lead.

Huh, didn't know that! Via https://en.wikipedia.org/wiki/Led_Zeppelin#Formation:_1966%E... : > One account of how the new band's name was chosen held that Moon and Entwistle had suggested that a supergroup with Page and Beck would go down like a "lead balloon", an idiom for being very unsuccessful or unpopular.[21] The group dropped the 'a' in lead at the suggestion of [manager] Peter Grant, so that those unfamiliar…

> And one could be forgiven for thinking that a formation of flying things would necessarily have one member in the lead position.

Indeed. In which case you would have the lead zeppelin, and the led zeppelins.

Re: Is the world really running out of sand?

#96

Post by ChuckMcM »

JoeAltmaier wrote: post #89

The whole idea of making your own sand is not sound. It will cost more, perhaps many times more. Seems clear when you think about it: hard to beat the cost of 'natural' sand because you just drive over and load it up. Add any more to that process, it's gonna go up in price. Including crushing rock etc - energy-intensive, then sieving. All add cost over and above, well, just hauling. And vague comments about 'couldn't…

Did you watch the entire video? I ask because Grady discusses EXACTLY this point.

He explains that the whole 'more expensive' thing is really just noting the actual cost of sand versus ignoring the externalized costs of mining it. When you dig up a river bed there is a cost there that isn't necessarily reflected in the cost of the sand you mined from there, sometimes because that cost is passed on to someone else who has to remediate the site after you mined it (like taxpayers). He empirically points out that different sands need a different water/cement ratio and also points out that the papers on sand use in concrete understand that. The 'bug' seems to be that people just add 'x' water to the mix and if the sand changes they might get different results.

Re: Is the world really running out of sand?

#98

Post by FredPret »

caust1c wrote: post #35

Grady is a hero in engineering reporting and documentaries. I've learned so much about how the world works in other engineering disciplines from Practical Engineering, and often in neglected fields that are losing talent faster than it can be replaced. It gives me hope that teenagers are watching his videos and becoming inspired to go into infrastructure. More than anything, I appreciate his calm and reasoned perspec…

100% - he calmly explains various approaches and their tradeoffs.

He’s not exactly a traditional journalist, but this is what I want the future of journalism to be like. People with subject matter expertise explaining their thing simply and clearly.

Re: Is the world really running out of sand?

#99

Post by FredPret »

lofaszvanitt wrote: post #94

Just like the US debt is about to collapse on pepl and kill the economy, but ... ... it never happens.

Public debt is more like a brake that gets worse and worse really slowly over time.

And then it suddenly explodes - more and more of the budget goes to interest payments instead of procurement.

At one point the government has to borrow to make payments on the debt, and then you’ve got a very bad spiral.

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