Global sand shortage and rocket mass builds

https://www.equaltimes.org/as-demand-for-it-accelerates#.ZB-szRYpAlQ

Just heard from a permaculturist (Killian O’Brien) that we have a global sand shortage too—along with metals like lithium and cobolt—and in web searching I found the article posted above.

Well, we use a LOT of sand (must be beach or river sand, not desert sand that is too smooth for a lot of industrial uses, and they’re talking about regulating the supply soon) in making concrete and asphalt, so if we didn’t need to drive anywhere and did natural buildings we’d be well ahead.  And the article talks about recycling sand by reusing concrete debris.

I would submit that building a rocket mass heater can be done with less sand not just by stretching the materials with rubble but also plain silt as filler.  It might take longer for everything to settle, and you would probably need to put it in a shelter to dry for a few months before construction, but sand is not infinite.

The article says we extract more sand than fossil fuels even, and it causes lots of problems.  I extracted mine from the quarry across the road, and could have just dug it up from my yard if I had equipment or time, but if I were to redo it now I’d consider supplementing with fill.

The pebble style rocket heater doesn’t need to be solid cob-rubble mix either, how does that stand up to being sat on?

The issue at hand is the "sharp sand" required for making concrete. This is a significant issue, and you are quite right to raise it.

But I respectfully suggest that is not a problem for mass heaters. What has been proposed around here is a compacted thermal mass of clay, silt, sand, gravel, chopped straw, rinsed-out horseshit, and whatever local materials can be bashed together. As long as it's a reasonably contiguous thermal mass, it should work.

My 2c.

I've heard of this issue for some time now, and it would benefit from more people being aware of it.

I've read of places where the sand is being "stolen" where it's put infrastructure like bridges, at risk.

Like anything else humans use, ideally one should try to determine its source. Is it from a local quarry that seems to be reasonably responsibly managed vs being shipped from who knows where under who knows what conditions? Not to mention, using it thoughtfully!

I've been reading a book about earthquakes. It describes a problem of irresponsible builders taking advantage of the need for instant housing following a quake by using "non-sharp" sand in mortar and now these old homes are at greater risk if there's another quake, than buildings built with quality mortar. So not using the right stuff in a situation that *needs* the right stuff is a problem.  Buildings that collapse are a huge environmental waste. Personally, I'd like to see more available research identifying  standards and building techniques that will make sure that any new buildings will withstand more than what Mother Nature currently throws at them - storms have been getting bigger, more people are living in at-risk zones, and we've not tended to teach about these risks in our education systems. We can't ask the critical questions if we don't know to ask them? If all the focus is on tornadoes, we might not think to ask about earthquakes or landslides. Too often it's all about cheap short-term goals, rather than buildings that can last for hundreds of years.

Thanks for replying.  The information I have is that you _do_ need sharp sand (mountain sand, specifically, not river sand or beach sand) for making cob that can have structural integrity (e.g. stand up under a person sitting on it).  I believe that's what it says in the Rocket Mass Heater Builder's Guide by Erica and Ernie.  

It is fairly abundant in my neck of the woods, but it isn't nearly as abundant as desert sand.

Douglas Alpenstock wrote:The issue at hand is the "sharp sand" required for making concrete. This is a significant issue, and you are quite right to raise it.

But I respectfully suggest that is not a problem for mass heaters. What has been proposed around here is a compacted thermal mass of clay, silt, sand, gravel, chopped straw, rinsed-out horseshit, and whatever local materials can be bashed together. As long as it's a reasonably contiguous thermal mass, it should work.

My 2c.

Personally, I would just add more clay to the mix to solidify the mass, since this is what I can source locally. It is mighty close to concrete as long as it stays dry.

But every area is different, with varying local materials, and there may be other considerations at play. Perhaps sharp sand is needed for a finish coat?

Where I live, crushed glass is one alternative to sharp sand but it has its drawbacks.
Crushed glass can be used as a direct replacement to sand in virtually every instance but you have to wear a breathing mask and gloves due to the dust partial's and sharp edges.
It was more popular a few years ago but has not really caught on in a big way, I still see it being used for laying floors but not so much for plastering.
I think the main issue was cost of manufacture, it is easy to crush old bottles but too expensive to regulate the grain size and remove the dust.

Thermal cob, the bulk mass for a bench, I am sure can be made with any kind of sand and other dense materials. Structural cob, the outer few inches of a bench or a bell enclosure, would need to use quality materials for durability. I would include some straw for that; the minuscule decrease in density and conductivity is more than offset by the increased strength.

I'm hoping to make sand from glass bottles in a oversized rock tumbler.
For me this is less about the world running out of sand and more about getting free building material.
It would still require electricity,  but would also be a good match for a solar pv system.

William Bronson wrote:It would still require electricity,  but would also be a good match for a solar pv system.

Particularly at times when you expect to be producing more electricity than you need - such as sunny summer weather - but you've sized your system for cloudier winter weather.

Hello All!

I’ve heard crushed shale is an expectable substitute. We have an abundance of shale on our property and have been wondering how best to crush it ourselves without resorting to industrial equipment. I’m also curious as to the size range that would be ideal for making Cobb. Does anyone else have experience crushing or sieving their own shale?

Thanks!

I haven't heard anything about crushed shale's acceptability as a sand substitute, but the regional bedrock here is shale, and the glaciers ground lots of it into clay and more into sand and gravel sized pieces. My clay bank is an unsorted mix of all of the above, and makes excellent cob as is with no additives. The sand component might not be great for concrete or mortar if separated (not very strong), but it is plenty strong enough for cob.


As for size, I think every size will be helpful depending on the particular cob function. For bulk structural cob, I just pick out stones bigger than a golf ball. For finish cob, I would probably dry and sieve it to remove pieces bigger than 1/8" to 1/4" or so.

William Bronson wrote:I'm hoping to make sand from glass bottles in a oversized rock tumbler.
For me this is less about the world running out of sand and more about getting free building material.
It would still require electricity,  but would also be a good match for a solar pv system.

I have only seen polished material come out of rock tumblers, which seems the opposite of sharp sand.  Do you have a special strategy for breaking the glass as opposed to polishing?  Is there something I don’t yet understand about the process?

Thekla is correct.

Tumbling rounds the edges.

Spent many years running a glassblowing studio and sand has always been an issue there.

For us batching our own glasses, the chemical content other than the quartz was the issue.

I had a lot of experience with tumbling because one of my main products was furnace beads, which have to be tumbled to finish them.

To get "sharp" broken glass you will need some sort of crusher.
One low budget trick for doing that we used in the glass studios was an under the sink garbage disposal, building a stand to keep it upright.
As long as you feed a good bit of water to it while crushing the glass it will last a long time. This has another benefit in taking care of the dust issue. Glass dust is a major health hazard.
You will have to reduce the glass pieces to a size that will fit. Hammer usually.
It does require electricity.
Noisy!

Unfortunately, I don't know of any middle ground between the disposal and an actual ore crusher, which they do make small sizes of but are extremely expensive.
https://www.sepor.com/chipmunk-and-badger-jaw-crushers/

It always pays to look at the recycling programs near you if they process glass. Some crush the glass for more economical transport.

Oh, wow!  Did this hit a long-standing sore spot!  I have been in construction for over 60 years.  I hate to have to tell you, but it is not just sand that is in failing supply.  It is aggregate as a whole.  Certain use cases have required shipping of sand across oceans (really).  Much of the issue, IMHO is the engineers involved in construction.  Story from when I began working with FEMA on disasters.  I was asked to accompany an inspector to a site visit since I was a hydrologist.  My background included excavation, construction, geotechnical soils work and graduate environmental hydrogeology.  When I got to the site, we were reviewing a lock on the Erie Canal located in the Mohawk River.  A small feeder stream, the Schoharie Creek, had created a sand bar immediately below where it entered the much larger Mohawk River.  The bar, after the latest flood, had expanded to where it was causing problems with the lock gates on the upstream side.  Since, at that time, the NY Thruway Authority owned the Canal Corp, there were at least 40 to 50 engineers and official wandering around discussing how much money the State needed to remove the sand bar.  The general consensus came to a federal share (@75%) of about $750,000.00.  I looked at the situation and asked a simple question.  Since the area was moderately mature, construction-wise, aggregate and sand was hard to come by.  Would not a gravel company jump at the opportunity to mine the sand bar since removal was needed anyway?  Dead silence.  A couple of weeks later, I saw the inspector and asking how his project was coming.  His response?  "No project."  They had asked a gravel company if they would like to mine the sand bar for free and had gotten an enthusiastic "Yes!"  No federal or state funding was needed to fix that problem.

Far too often, I have seen engineers build bypass channels for flood water only to create massive sand bars in rivers that then begin to force the river to eat out the opposite bank.  I know of one, financed and managed by the National Resource Conservation Service (NRCS) that continues to create that damage to a living stream.  Every levee and dam placed in a stream tends to create similar problems.  One reason the Corps of Engineers (USACE) has to continually dredge the Mississippi River is that their levees create sedimentation traps that drop washed gravel and clays in areas that then reduce the levees' carrying capacity.  The Rio Grande River silts up regularly due to controlled release of muddy water from upstream dams (only one of dozens of examples I am aware of).  Because there is insufficient flooding to clean the channel, vegetation grows on sediments, forcing future flood water to run, often miles out of the channel.  Of course, when high velocity water hits normal ground, it digs new channels, moving the sediment downstream to create more problems.

I have not even begun to describe the environmentally damaging and unsustainable use of placing sand on beaches.  That job nets the USACE billions annually.

Normal farming eats soil away.  It either blows away or runs off in heavy rains.  Many areas of the midwest that had several yards of topsoil are down to precious feet.  All that material is aggregate that flows down our rivers and into the sea.  While on its journey, it creates one issue after another.  Practices such a permiculture are one of the best defenses, but are still too small to stem the bleeding of our aggregates.  And then someone wants a particular concrete and ships aggregate from some poor area to a richer one.  Yes, the local community is getting work, but at what price?  That aggregate is finite.  Of course some governments allow massive damage.  To build the Three Rivers Gorge in China in an attempt to control flooding on the Yangtze (Yellow) River, they placed explosives and dropped entire gorge walls into the river and built on top of the rubble.  Of course they also relocated over 3 million people, but to the ruling Party, that was a small price to pay.  Of course, massive damage was absorbed by the mighty river, but who cares?

The issue with sand and grinding glass is often silicosis, a disease created when someone breathes in silica dust or ground mica or any other form of micro-silica.  It cuts the lung tissue and makes breathing hard, if not impossible.  Control such dust with sprays of water, use ball mills to grind up sandstone or shale.  Sandstone is the best source of bedrock to turn into sand.  It is composed of sand, thus the name.  Shale is not as useful due to the fact that shale is composed of very fine sand, silt and clay.  

Back in the 50's, cinders from the railroad and coal furnaces was used to make cinder blocks.  It has been found that old cinder block, after 40 to 50 years (far less if exposed to flood waters) will disintegrate and fail as a structural material, who knew?  It was a cheap use for what was considered a waste product and allowed homes to be constructed for the poor or monetarily disadvantaged.  Those homes are now being used by minorities, senior citizens and the disability community - often in flood plains.  Throwaway people in throwaway homes.  But I digress.  Sometimes I know too much and it has to come out.

@RichardHenry thank you for all that information!

This thread helps explain something I have puzzled about.

When we bought an apartment in Istanbul last year, the sellers explained that their family construction business had built the structure. They knew that the sand used was very high quality. This was a selling point as Istanbul sits on a fault line and earthquakes are a major concern.

But because I am ignorant about building construction I did not understand how quality of sand made a difference nor did I even understand what good quality meant for sand.

By the way, if anyone knows anyone here in Türkiye especially near Istanbul who are into urban permaculture please let me know.

Thank you!

I love the idea of using a garbage disposal.
I figured a "light tumbling" might be enough to get sharp sand, but whatever works.
For what it's worth, I think a crusher that is strictly for glass could be fairly simple to build for anyone who can weld.

Joshua Myrvaagnes wrote:

The pebble style rocket heater doesn’t need to be solid cob-rubble mix either, how does that stand up to being sat on?

A pebble style rocket mass heater is created by building a box structure that contains the pebbles so you aren't actually sitting on the pebbles.  Instead you are sitting on a box that is full of them.  As long as the box is strong, which it should be to handle all the weight of the pebbles, then sitting on it is just fine.  I'll sit, stand. lay out on mine all the time!  :)  

In making my pebble style I did still use some cob around the core and manifold, as well as to seal the barrel down, but it was far less cob than a traditional RMH would use.

David Huang wrote:

Joshua Myrvaagnes wrote:

The pebble style rocket heater doesn’t need to be solid cob-rubble mix either, how does that stand up to being sat on?

A pebble style rocket mass heater is created by building a box structure that contains the pebbles so you aren't actually sitting on the pebbles.  Instead you are sitting on a box that is full of them.  As long as the box is strong, which it should be to handle all the weight of the pebbles, then sitting on it is just fine.  I'll sit, stand. lay out on mine all the time!  :)  

In making my pebble style I did still use some cob around the core and manifold, as well as to seal the barrel down, but it was far less cob than a traditional RMH would use.

I also wonder if we aren't dealing with a "The perfect is the enemy of the good." situation here... Where a classic "One tenth the wood of a conventional wood stove." sculpted cob RMH is an ideal, and the pebble-style is slightly less efficient due to all of the tiny air gaps, but still darn good!
There might even be a middle version! A pebble-style enclosure, but filled with a less ideal cob mixture (insert round sand here...). Where the structure and aesthetics are in the enclosure, and the infill requires even less rigorous selection of materials and/or skill (or slightly different skills?) to construct.

I've wondered a similar thing Kenneth.  Though my understanding of traditional cob RMHs and pebble style is that the cob transfers the heat through conduction of the solid mass while the pebble style needs the air gaps because there is a convection factor in play.  Pebble style have air intake vents below the box and out flow up at the top.  I would still think a box structure filled with mass could work, but I think there might be more concerns about what materials to build the box out of so it could potentially handle a higher level of heat directly conducting to it.  When making mine I made sure to get a bit of insulation strategically placed whenever the heat transfer pipes started getting too close to the 2x4s.

Not all rocket mass heaters have to be massive, even though that is what the name implies. The Love Shack on Wheaton Labs has a small, but efficient build design which incorporates a 'cob hat' to increase its mass. See it in action here:
 

Georgia Lenhart wrote:
I’ve heard crushed shale is an expectable substitute. We have an abundance of shale on our property and have been wondering how best to crush it ourselves without resorting to industrial equipment.

Our neighbor has a gravel pit on his land that has shale gravel.  It's not used commercially, just his personal use.  He puts the gravel on his driveway but within a couple of years it turns into a course sand and he has to keep adding new gravel.  I wouldn't think any stone would break down that quickly but it sure looks like he has a sand driveway.